Compress-Stream-Zstd
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ext/zstd/CHANGELOG view on Meta::CPAN
API : streaming : decompression : changed : automatic implicit reset when chain-decoding new frames without init
API : experimental : added : dictID retrieval functions, and ZSTD_initCStream_srcSize()
API : zbuff : changed : prototypes now generate deprecation warnings
lib : improved : faster decompression speed at ultra compression settings and 32-bits mode
lib : changed : only public ZSTD_ symbols are now exposed
lib : changed : reduced usage of stack memory
lib : fixed : several corner case bugs, by Nick Terrell
cli : new : gzstd, experimental version able to decode .gz files, by Przemyslaw Skibinski
cli : new : preserve file attributes
cli : new : added zstdless and zstdgrep tools
cli : fixed : status displays total amount decoded, even for file consisting of multiple frames (like pzstd)
cli : fixed : zstdcat
zlib_wrapper : added support for gz* functions, by Przemyslaw Skibinski
install : better compatibility with FreeBSD, by Dimitry Andric
source tree : changed : zbuff source files moved to lib/deprecated
v1.1.1 (Nov 2, 2016)
New : command -M#, --memory=, --memlimit=, --memlimit-decompress= to limit allowed memory consumption
New : doc/zstd_manual.html, by Przemyslaw Skibinski
Improved : slightly better compression ratio at --ultra levels (>= 20)
Improved : better memory usage when using streaming compression API, thanks to @Rogier-5 report
ext/zstd/README.md view on Meta::CPAN
Compression Ratio | Compression Speed | Decompression Speed
------------------|-------------------|--------------------
 |  | 
These compression gains are achieved while simultaneously providing _faster_ compression and decompression speeds.
Training works if there is some correlation in a family of small data samples. The more data-specific a dictionary is, the more efficient it is (there is no _universal dictionary_).
Hence, deploying one dictionary per type of data will provide the greatest benefits.
Dictionary gains are mostly effective in the first few KB. Then, the compression algorithm will gradually use previously decoded content to better compress the rest of the file.
### Dictionary compression How To:
1. Create the dictionary
`zstd --train FullPathToTrainingSet/* -o dictionaryName`
2. Compress with dictionary
`zstd -D dictionaryName FILE`
ext/zstd/contrib/linux-kernel/linux_zstd.h view on Meta::CPAN
* @input: Source buffer. `input.pos` is updated to indicate how much data was
* read. Note that it may not consume the entire input, in which case
* `input.pos < input.size`, and it's up to the caller to present
* remaining data again.
*
* The `input` and `output` buffers may be any size. Guaranteed to make some
* forward progress if `input` and `output` are not empty.
* zstd_decompress_stream() will not consume the last byte of the frame until
* the entire frame is flushed.
*
* Return: Returns 0 iff a frame is completely decoded and fully flushed.
* Otherwise returns a hint for the number of bytes to use as the
* input for the next function call or an error, which can be checked
* using zstd_is_error(). The size hint will never load more than the
* frame.
*/
size_t zstd_decompress_stream(zstd_dstream *dstream, zstd_out_buffer *output,
zstd_in_buffer *input);
/* ====== Frame Inspection Functions ====== */
ext/zstd/contrib/pzstd/Pzstd.cpp view on Meta::CPAN
while (status == FileStatus::Continue && !state.errorHolder.hasError()) {
// Make a new input queue that we will put the frames's bytes into.
auto in = std::make_shared<BufferWorkQueue>();
auto inGuard = makeScopeGuard([&] { in->finish(); });
// Make a output queue that decompress will put the decompressed data into
auto out = std::make_shared<BufferWorkQueue>();
size_t frameSize;
{
// Calculate the size of the next frame.
// frameSize is 0 if the frame info can't be decoded.
Buffer buffer(SkippableFrame::kSize);
auto bytesRead = std::fread(buffer.data(), 1, buffer.size(), fd);
totalBytesRead += bytesRead;
status = fileStatus(fd);
if (bytesRead == 0 && status != FileStatus::Continue) {
break;
}
buffer.subtract(buffer.size() - bytesRead);
frameSize = SkippableFrame::tryRead(buffer.range());
in->push(std::move(buffer));
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
/// Decode a single symbol and read in enough bits to refresh the state
static inline u8 HUF_decode_symbol(const HUF_dtable *const dtable,
u16 *const state, const u8 *const src,
i64 *const offset);
/// Read in a full state's worth of bits to initialize it
static inline void HUF_init_state(const HUF_dtable *const dtable,
u16 *const state, const u8 *const src,
i64 *const offset);
/// Decompresses a single Huffman stream, returns the number of bytes decoded.
/// `src_len` must be the exact length of the Huffman-coded block.
static size_t HUF_decompress_1stream(const HUF_dtable *const dtable,
ostream_t *const out, istream_t *const in);
/// Same as previous but decodes 4 streams, formatted as in the Zstandard
/// specification.
/// `src_len` must be the exact length of the Huffman-coded block.
static size_t HUF_decompress_4stream(const HUF_dtable *const dtable,
ostream_t *const out, istream_t *const in);
/// Initialize a Huffman decoding table using the table of bit counts provided
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
static size_t FSE_decompress_interleaved2(const FSE_dtable *const dtable,
ostream_t *const out,
istream_t *const in);
/// Initialize a decoding table using normalized frequencies.
static void FSE_init_dtable(FSE_dtable *const dtable,
const i16 *const norm_freqs, const int num_symbs,
const int accuracy_log);
/// Decode an FSE header as defined in the Zstandard format specification and
/// use the decoded frequencies to initialize a decoding table.
static void FSE_decode_header(FSE_dtable *const dtable, istream_t *const in,
const int max_accuracy_log);
/// Initialize an FSE table that will always return the same symbol and consume
/// 0 bits per symbol, to be used for RLE mode in sequence commands
static void FSE_init_dtable_rle(FSE_dtable *const dtable, const u8 symb);
/// Free the malloc'ed parts of a decoding table
static void FSE_free_dtable(FSE_dtable *const dtable);
/*** END FSE PRIMITIVES ***************/
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
// of retransmitting
HUF_dtable literals_dtable;
FSE_dtable ll_dtable;
FSE_dtable ml_dtable;
FSE_dtable of_dtable;
// The last 3 offsets for the special "repeat offsets".
u64 previous_offsets[3];
} frame_context_t;
/// The decoded contents of a dictionary so that it doesn't have to be repeated
/// for each frame that uses it
struct dictionary_s {
// Entropy tables
HUF_dtable literals_dtable;
FSE_dtable ll_dtable;
FSE_dtable ml_dtable;
FSE_dtable of_dtable;
// Raw content for backreferences
u8 *content;
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
istream_t *const in);
// Decode the literals section of a block
static size_t decode_literals(frame_context_t *const ctx, istream_t *const in,
u8 **const literals);
// Decode the sequences part of a block
static size_t decode_sequences(frame_context_t *const ctx, istream_t *const in,
sequence_command_t **const sequences);
// Execute the decoded sequences on the literals block
static void execute_sequences(frame_context_t *const ctx, ostream_t *const out,
const u8 *const literals,
const size_t literals_len,
const sequence_command_t *const sequences,
const size_t num_sequences);
// Copies literals and returns the total literal length that was copied
static u32 copy_literals(const size_t seq, istream_t *litstream,
ostream_t *const out);
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
HUF_free_dtable(&ctx->literals_dtable);
decode_huf_table(&ctx->literals_dtable, &huf_stream);
} else {
// If the previous Huffman table is being repeated, ensure it exists
if (!ctx->literals_dtable.symbols) {
CORRUPTION();
}
}
size_t symbols_decoded;
if (num_streams == 1) {
symbols_decoded = HUF_decompress_1stream(&ctx->literals_dtable, &lit_stream, &huf_stream);
} else {
symbols_decoded = HUF_decompress_4stream(&ctx->literals_dtable, &lit_stream, &huf_stream);
}
if (symbols_decoded != regenerated_size) {
CORRUPTION();
}
return regenerated_size;
}
// Decode the Huffman table description
static void decode_huf_table(HUF_dtable *const dtable, istream_t *const in) {
// "All literal values from zero (included) to last present one (excluded)
// are represented by Weight with values from 0 to Max_Number_of_Bits."
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
}
}
} else {
// The weights are FSE encoded, decode them before we can construct the
// table
istream_t fse_stream = IO_make_sub_istream(in, header);
ostream_t weight_stream = IO_make_ostream(weights, HUF_MAX_SYMBS);
fse_decode_hufweights(&weight_stream, &fse_stream, &num_symbs);
}
// Construct the table using the decoded weights
HUF_init_dtable_usingweights(dtable, weights, num_symbs);
}
static void fse_decode_hufweights(ostream_t *weights, istream_t *const in,
int *const num_symbs) {
const int MAX_ACCURACY_LOG = 7;
FSE_dtable dtable;
// "An FSE bitstream starts by a header, describing probabilities
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
const size_t len = IO_istream_len(in);
const u8 *const src = IO_get_read_ptr(in, len);
// "After writing the last bit containing information, the compressor writes
// a single 1-bit and then fills the byte with 0-7 0 bits of padding."
const int padding = 8 - highest_set_bit(src[len - 1]);
// The offset starts at the end because FSE streams are read backwards
i64 bit_offset = (i64)(len * 8 - (size_t)padding);
// "The bitstream starts with initial state values, each using the required
// number of bits in their respective accuracy, decoded previously from
// their normalized distribution.
//
// It starts by Literals_Length_State, followed by Offset_State, and finally
// Match_Length_State."
FSE_init_state(&states.ll_table, &states.ll_state, src, &bit_offset);
FSE_init_state(&states.of_table, &states.of_state, src, &bit_offset);
FSE_init_state(&states.ml_table, &states.ml_state, src, &bit_offset);
for (size_t i = 0; i < num_sequences; i++) {
// Decode sequences one by one
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
i64 *const offset) {
// "Each symbol is a code in its own context, which specifies Baseline and
// Number_of_Bits to add. Codes are FSE compressed, and interleaved with raw
// additional bits in the same bitstream."
// Decode symbols, but don't update states
const u8 of_code = FSE_peek_symbol(&states->of_table, states->of_state);
const u8 ll_code = FSE_peek_symbol(&states->ll_table, states->ll_state);
const u8 ml_code = FSE_peek_symbol(&states->ml_table, states->ml_state);
// Offset doesn't need a max value as it's not decoded using a table
if (ll_code > SEQ_MAX_CODES[seq_literal_length] ||
ml_code > SEQ_MAX_CODES[seq_match_length]) {
CORRUPTION();
}
// Read the interleaved bits
sequence_command_t seq;
// "Decoding starts by reading the Number_of_Bits required to decode Offset.
// It then does the same for Match_Length, and then for Literals_Length."
seq.offset = ((u32)1 << of_code) + STREAM_read_bits(src, of_code, offset);
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
while (bit_offset > -dtable->max_bits) {
// Iterate over the stream, decoding one symbol at a time
IO_write_byte(out, HUF_decode_symbol(dtable, &state, src, &bit_offset));
symbols_written++;
}
// "The process continues up to reading the required number of symbols per
// stream. If a bitstream is not entirely and exactly consumed, hence
// reaching exactly its beginning position with all bits consumed, the
// decoding process is considered faulty."
// When all symbols have been decoded, the final state value shouldn't have
// any data from the stream, so it should have "read" dtable->max_bits from
// before the start of `src`
// Therefore `offset`, the edge to start reading new bits at, should be
// dtable->max_bits before the start of the stream
if (bit_offset != -dtable->max_bits) {
CORRUPTION();
}
return symbols_written;
}
static size_t HUF_decompress_4stream(const HUF_dtable *const dtable,
ostream_t *const out, istream_t *const in) {
// "Compressed size is provided explicitly : in the 4-streams variant,
// bitstreams are preceded by 3 unsigned little-endian 16-bits values. Each
// value represents the compressed size of one stream, in order. The last
// stream size is deducted from total compressed size and from previously
// decoded stream sizes"
const size_t csize1 = IO_read_bits(in, 16);
const size_t csize2 = IO_read_bits(in, 16);
const size_t csize3 = IO_read_bits(in, 16);
istream_t in1 = IO_make_sub_istream(in, csize1);
istream_t in2 = IO_make_sub_istream(in, csize2);
istream_t in3 = IO_make_sub_istream(in, csize3);
istream_t in4 = IO_make_sub_istream(in, IO_istream_len(in));
size_t total_output = 0;
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
free(dtable->symbols);
free(dtable->num_bits);
memset(dtable, 0, sizeof(HUF_dtable));
}
/******* END HUFFMAN PRIMITIVES ***********************************************/
/******* FSE PRIMITIVES *******************************************************/
/// For more description of FSE see
/// https://github.com/Cyan4973/FiniteStateEntropy/
/// Allow a symbol to be decoded without updating state
static inline u8 FSE_peek_symbol(const FSE_dtable *const dtable,
const u16 state) {
return dtable->symbols[state];
}
/// Consumes bits from the input and uses the current state to determine the
/// next state
static inline void FSE_update_state(const FSE_dtable *const dtable,
u16 *const state, const u8 *const src,
i64 *const offset) {
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
// Decode until we overflow the stream
// Since we decode in reverse order, overflowing the stream is offset going
// negative
size_t symbols_written = 0;
while (1) {
// "The number of symbols to decode is determined by tracking bitStream
// overflow condition: If updating state after decoding a symbol would
// require more bits than remain in the stream, it is assumed the extra
// bits are 0. Then, the symbols for each of the final states are
// decoded and the process is complete."
IO_write_byte(out, FSE_decode_symbol(dtable, &state1, src, &offset));
symbols_written++;
if (offset < 0) {
// There's still a symbol to decode in state2
IO_write_byte(out, FSE_peek_symbol(dtable, state2));
symbols_written++;
break;
}
IO_write_byte(out, FSE_decode_symbol(dtable, &state2, src, &offset));
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
// over time, decreasing number of bits
dtable->num_bits[i] = (u8)(accuracy_log - highest_set_bit(next_state_desc));
// Baseline increases until the bit threshold is passed, at which point
// it resets to 0
dtable->new_state_base[i] =
((u16)next_state_desc << dtable->num_bits[i]) - size;
}
}
/// Decode an FSE header as defined in the Zstandard format specification and
/// use the decoded frequencies to initialize a decoding table.
static void FSE_decode_header(FSE_dtable *const dtable, istream_t *const in,
const int max_accuracy_log) {
// "An FSE distribution table describes the probabilities of all symbols
// from 0 to the last present one (included) on a normalized scale of 1 <<
// Accuracy_Log .
//
// It's a bitstream which is read forward, in little-endian fashion. It's
// not necessary to know its exact size, since it will be discovered and
// reported by the decoding process.
if (max_accuracy_log > FSE_MAX_ACCURACY_LOG) {
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
}
// "Then follows each symbol value, from 0 to last present one. The number
// of bits used by each field is variable. It depends on :
//
// Remaining probabilities + 1 : example : Presuming an Accuracy_Log of 8,
// and presuming 100 probabilities points have already been distributed, the
// decoder may read any value from 0 to 255 - 100 + 1 == 156 (inclusive).
// Therefore, it must read log2sup(156) == 8 bits.
//
// Value decoded : small values use 1 less bit : example : Presuming values
// from 0 to 156 (inclusive) are possible, 255-156 = 99 values are remaining
// in an 8-bits field. They are used this way : first 99 values (hence from
// 0 to 98) use only 7 bits, values from 99 to 156 use 8 bits. "
i32 remaining = 1 << accuracy_log;
i16 frequencies[FSE_MAX_SYMBS];
int symb = 0;
while (remaining > 0 && symb < FSE_MAX_SYMBS) {
// Log of the number of possible values we could read
ext/zstd/doc/educational_decoder/zstd_decompress.c view on Meta::CPAN
const u16 lower_mask = ((u16)1 << (bits - 1)) - 1;
const u16 threshold = ((u16)1 << bits) - 1 - (remaining + 1);
if ((val & lower_mask) < threshold) {
IO_rewind_bits(in, 1);
val = val & lower_mask;
} else if (val > lower_mask) {
val = val - threshold;
}
// "Probability is obtained from Value decoded by following formula :
// Proba = value - 1"
const i16 proba = (i16)val - 1;
// "It means value 0 becomes negative probability -1. -1 is a special
// probability, which means "less than 1". Its effect on distribution
// table is described in next paragraph. For the purpose of calculating
// cumulated distribution, it counts as one."
remaining -= proba < 0 ? -proba : proba;
frequencies[symb] = proba;
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
__`Data_Block`__
Detailed in [`Blocks`](#blocks).
That’s where compressed data is stored.
__`Content_Checksum`__
An optional 32-bit checksum, only present if `Content_Checksum_flag` is set.
The content checksum is the result
of [xxh64() hash function](https://cyan4973.github.io/xxHash/)
digesting the original (decoded) data as input, and a seed of zero.
The low 4 bytes of the checksum are stored in __little-endian__ format.
### `Frame_Header`
The `Frame_Header` has a variable size, with a minimum of 2 bytes,
and up to 14 bytes depending on optional parameters.
The structure of `Frame_Header` is following:
| `Frame_Header_Descriptor` | [`Window_Descriptor`] | [`Dictionary_ID`] | [`Frame_Content_Size`] |
| ------------------------- | --------------------- | ----------------- | ---------------------- |
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
`DID_Field_Size` is directly derived from value of `Dictionary_ID_flag`.
1 byte can represent an ID 0-255.
2 bytes can represent an ID 0-65535.
4 bytes can represent an ID 0-4294967295.
Format is __little-endian__.
It's allowed to represent a small ID (for example `13`)
with a large 4-bytes dictionary ID, even if it is less efficient.
A value of `0` has same meaning as no `Dictionary_ID`,
in which case the frame may or may not need a dictionary to be decoded,
and the ID of such a dictionary is not specified.
The decoder must know this information by other means.
#### `Frame_Content_Size`
This is the original (uncompressed) size. This information is optional.
`Frame_Content_Size` uses a variable number of bytes, provided by `FCS_Field_Size`.
`FCS_Field_Size` is provided by the value of `Frame_Content_Size_flag`.
`FCS_Field_Size` can be equal to 0 (not present), 1, 2, 4 or 8 bytes.
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
A compressed block consists of 2 sections :
- [Literals Section](#literals-section)
- [Sequences Section](#sequences-section)
The results of the two sections are then combined to produce the decompressed
data in [Sequence Execution](#sequence-execution)
#### Prerequisites
To decode a compressed block, the following elements are necessary :
- Previous decoded data, up to a distance of `Window_Size`,
or beginning of the Frame, whichever is smaller.
- List of "recent offsets" from previous `Compressed_Block`.
- The previous Huffman tree, required by `Treeless_Literals_Block` type
- Previous FSE decoding tables, required by `Repeat_Mode`
for each symbol type (literals lengths, match lengths, offsets)
Note that decoding tables aren't always from the previous `Compressed_Block`.
- Every decoding table can come from a dictionary.
- The Huffman tree comes from the previous `Compressed_Literals_Block`.
Literals Section
----------------
All literals are regrouped in the first part of the block.
They can be decoded first, and then copied during [Sequence Execution],
or they can be decoded on the flow during [Sequence Execution].
Literals can be stored uncompressed or compressed using Huffman prefix codes.
When compressed, a tree description may optionally be present,
followed by 1 or 4 streams.
| `Literals_Section_Header` | [`Huffman_Tree_Description`] | [jumpTable] | Stream1 | [Stream2] | [Stream3] | [Stream4] |
| ------------------------- | ---------------------------- | ----------- | ------- | --------- | --------- | --------- |
### `Literals_Section_Header`
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
That's a technical minimum, but it's not recommended to employ the 4 streams mode
for such a small quantity, that would be wasteful.
A more practical lower bound would be around ~256 bytes.
#### Raw Literals Block
The data in Stream1 is `Regenerated_Size` bytes long,
it contains the raw literals data to be used during [Sequence Execution].
#### RLE Literals Block
Stream1 consists of a single byte which should be repeated `Regenerated_Size` times
to generate the decoded literals.
#### Compressed Literals Block and Treeless Literals Block
Both of these modes contain Huffman encoded data.
For `Treeless_Literals_Block`,
the Huffman table comes from previously compressed literals block,
or from a dictionary.
### `Huffman_Tree_Description`
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
Jump Table is 6 bytes long, and consists of three 2-byte __little-endian__ fields,
describing the compressed sizes of the first three streams.
`Stream4_Size` is computed from `Total_Streams_Size` minus sizes of other streams:
`Stream4_Size = Total_Streams_Size - 6 - Stream1_Size - Stream2_Size - Stream3_Size`.
`Stream4_Size` is necessarily `>= 1`. Therefore,
if `Total_Streams_Size < Stream1_Size + Stream2_Size + Stream3_Size + 6 + 1`,
data is considered corrupted.
Each of these 4 bitstreams is then decoded independently as a Huffman-Coded stream,
as described in [Huffman-Coded Streams](#huffman-coded-streams)
Sequences Section
-----------------
A compressed block is a succession of _sequences_ .
A sequence is a literal copy command, followed by a match copy command.
A literal copy command specifies a length.
It is the number of bytes to be copied (or extracted) from the Literals Section.
A match copy command specifies an offset and a length.
When all _sequences_ are decoded,
if there are literals left in the _literals section_,
these bytes are added at the end of the block.
This is described in more detail in [Sequence Execution](#sequence-execution).
The `Sequences_Section` regroup all symbols required to decode commands.
There are 3 symbol types : literals lengths, offsets and match lengths.
They are encoded together, interleaved, in a single _bitstream_.
The `Sequences_Section` starts by a header,
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
Each symbol is a _code_ in its own context,
which specifies `Baseline` and `Number_of_Bits` to add.
_Codes_ are FSE compressed,
and interleaved with raw additional bits in the same bitstream.
##### Literals length codes
Literals length codes are values ranging from `0` to `35` included.
They define lengths from 0 to 131071 bytes.
The literals length is equal to the decoded `Baseline` plus
the result of reading `Number_of_Bits` bits from the bitstream,
as a __little-endian__ value.
| `Literals_Length_Code` | 0-15 |
| ---------------------- | ---------------------- |
| length | `Literals_Length_Code` |
| `Number_of_Bits` | 0 |
| `Literals_Length_Code` | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 |
| ---------------------- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- |
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
| `Literals_Length_Code` | 32 | 33 | 34 | 35 |
| ---------------------- | ---- | ---- | ---- | ---- |
| `Baseline` | 8192 |16384 |32768 |65536 |
| `Number_of_Bits` | 13 | 14 | 15 | 16 |
##### Match length codes
Match length codes are values ranging from `0` to `52` included.
They define lengths from 3 to 131074 bytes.
The match length is equal to the decoded `Baseline` plus
the result of reading `Number_of_Bits` bits from the bitstream,
as a __little-endian__ value.
| `Match_Length_Code` | 0-31 |
| ------------------- | ----------------------- |
| value | `Match_Length_Code` + 3 |
| `Number_of_Bits` | 0 |
| `Match_Length_Code` | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 |
| ------------------- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- |
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
For more explanation on FSE decoding, see the [FSE section](#fse).
For sequence decoding, a separate state keeps track of each
literal lengths, offsets, and match lengths symbols.
Some FSE primitives are also used.
For more details on the operation of these primitives, see the [FSE section](#fse).
##### Starting states
The bitstream starts with initial FSE state values,
each using the required number of bits in their respective _accuracy_,
decoded previously from their normalized distribution.
It starts by `Literals_Length_State`,
followed by `Offset_State`,
and finally `Match_Length_State`.
Reminder : always keep in mind that all values are read _backward_,
so the 'start' of the bitstream is at the highest position in memory,
immediately before the last `1`-bit for padding.
After decoding the starting states, a single sequence is decoded
`Number_Of_Sequences` times.
These sequences are decoded in order from first to last.
Since the compressor writes the bitstream in the forward direction,
this means the compressor must encode the sequences starting with the last
one and ending with the first.
##### Decoding a sequence
For each of the symbol types, the FSE state can be used to determine the appropriate code.
The code then defines the `Baseline` and `Number_of_Bits` to read for each type.
See the [description of the codes] for how to determine these values.
[description of the codes]: #the-codes-for-literals-lengths-match-lengths-and-offsets
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
it's not possible to use the default distribution to represent it.
```
short offsetCodes_defaultDistribution[29] =
{ 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,-1,-1,-1,-1,-1 };
```
Sequence Execution
------------------
Once literals and sequences have been decoded,
they are combined to produce the decoded content of a block.
Each sequence consists of a tuple of (`literals_length`, `offset_value`, `match_length`),
decoded as described in the [Sequences Section](#sequences-section).
To execute a sequence, first copy `literals_length` bytes
from the decoded literals to the output.
Then `match_length` bytes are copied from previous decoded data.
The offset to copy from is determined by `offset_value`:
if `offset_value > 3`, then the offset is `offset_value - 3`.
If `offset_value` is from 1-3, the offset is a special repeat offset value.
See the [repeat offset](#repeat-offsets) section for how the offset is determined
in this case.
The offset is defined as from the current position, so an offset of 6
and a match length of 3 means that 3 bytes should be copied from 6 bytes back.
Note that all offsets leading to previously decoded data
must be smaller than `Window_Size` defined in `Frame_Header_Descriptor`.
#### Repeat offsets
As seen in [Sequence Execution](#sequence-execution),
the first 3 values define a repeated offset and we will call them
`Repeated_Offset1`, `Repeated_Offset2`, and `Repeated_Offset3`.
They are sorted in recency order, with `Repeated_Offset1` meaning "most recent one".
If `offset_value == 1`, then the offset used is `Repeated_Offset1`, etc.
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
The number of bits used by each field is variable.
It depends on :
- Remaining probabilities + 1 :
__example__ :
Presuming an `Accuracy_Log` of 8,
and presuming 100 probabilities points have already been distributed,
the decoder may read any value from `0` to `256 - 100 + 1 == 157` (inclusive).
Therefore, it must read `log2sup(157) == 8` bits.
- Value decoded : small values use 1 less bit :
__example__ :
Presuming values from 0 to 157 (inclusive) are possible,
255-157 = 98 values are remaining in an 8-bits field.
They are used this way :
first 98 values (hence from 0 to 97) use only 7 bits,
values from 98 to 157 use 8 bits.
This is achieved through this scheme :
| Value read | Value decoded | Number of bits used |
| ---------- | ------------- | ------------------- |
| 0 - 97 | 0 - 97 | 7 |
| 98 - 127 | 98 - 127 | 8 |
| 128 - 225 | 0 - 97 | 7 |
| 226 - 255 | 128 - 157 | 8 |
Symbols probabilities are read one by one, in order.
Probability is obtained from Value decoded by following formula :
`Proba = value - 1`
It means value `0` becomes negative probability `-1`.
`-1` is a special probability, which means "less than 1".
Its effect on distribution table is described in the [next section].
For the purpose of calculating total allocated probability points, it counts as one.
[next section]:#from-normalized-distribution-to-decoding-tables
When a symbol has a __probability__ of `zero`,
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
Any remaining bit within the last byte is just unused.
#### From normalized distribution to decoding tables
The distribution of normalized probabilities is enough
to create a unique decoding table.
It follows the following build rule :
The table has a size of `Table_Size = 1 << Accuracy_Log`.
Each cell describes the symbol decoded,
and instructions to get the next state (`Number_of_Bits` and `Baseline`).
Symbols are scanned in their natural order for "less than 1" probabilities.
Symbols with this probability are being attributed a single cell,
starting from the end of the table and retreating.
These symbols define a full state reset, reading `Accuracy_Log` bits.
Then, all remaining symbols, sorted in natural order, are allocated cells.
Starting from symbol `0` (if it exists), and table position `0`,
each symbol gets allocated as many cells as its probability.
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
position += (tableSize>>1) + (tableSize>>3) + 3;
position &= tableSize-1;
```
A position is skipped if already occupied by a "less than 1" probability symbol.
`position` does not reset between symbols, it simply iterates through
each position in the table, switching to the next symbol when enough
states have been allocated to the current one.
The process guarantees that the table is entirely filled.
Each cell corresponds to a state value, which contains the symbol being decoded.
To add the `Number_of_Bits` and `Baseline` required to retrieve next state,
it's first necessary to sort all occurrences of each symbol in state order.
Lower states will need 1 more bit than higher ones.
The process is repeated for each symbol.
__Example__ :
Presuming a symbol has a probability of 5,
it receives 5 cells, corresponding to 5 state values.
These state values are then sorted in natural order.
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
The first state (`State1`) encodes the even indexed symbols,
and the second (`State2`) encodes the odd indexed symbols.
`State1` is initialized first, and then `State2`, and they take turns
decoding a single symbol and updating their state.
For more details on these FSE operations, see the [FSE section](#fse).
The number of symbols to decode is determined
by tracking bitStream overflow condition:
If updating state after decoding a symbol would require more bits than
remain in the stream, it is assumed that extra bits are 0. Then,
symbols for each of the final states are decoded and the process is complete.
#### Conversion from weights to Huffman prefix codes
All present symbols shall now have a `Weight` value.
It is possible to transform weights into `Number_of_Bits`, using this formula:
```
Number_of_Bits = (Weight>0) ? Max_Number_of_Bits + 1 - Weight : 0
```
Symbols are sorted by `Weight`.
Within same `Weight`, symbols keep natural sequential order.
Symbols with a `Weight` of zero are removed.
Then, starting from lowest `Weight`, prefix codes are distributed in sequential order.
__Example__ :
Let's presume the following list of weights has been decoded :
| Literal | 0 | 1 | 2 | 3 | 4 | 5 |
| -------- | --- | --- | --- | --- | --- | --- |
| `Weight` | 4 | 3 | 2 | 0 | 1 | 1 |
Sorted by weight and then natural sequential order,
it gives the following distribution :
| Literal | 3 | 4 | 5 | 2 | 1 | 0 |
| ---------------- | --- | --- | --- | --- | --- | ---- |
ext/zstd/doc/zstd_compression_format.md view on Meta::CPAN
FSE table for match lengths, and FSE table for literals lengths.
These tables populate the Repeat Stats literals mode and
Repeat distribution mode for sequence decoding.
It's finally followed by 3 offset values, populating recent offsets (instead of using `{1,4,8}`),
stored in order, 4-bytes __little-endian__ each, for a total of 12 bytes.
Each recent offset must have a value <= dictionary content size, and cannot equal 0.
__`Content`__ : The rest of the dictionary is its content.
The content act as a "past" in front of data to compress or decompress,
so it can be referenced in sequence commands.
As long as the amount of data decoded from this frame is less than or
equal to `Window_Size`, sequence commands may specify offsets longer
than the total length of decoded output so far to reference back to the
dictionary, even parts of the dictionary with offsets larger than `Window_Size`.
After the total output has surpassed `Window_Size` however,
this is no longer allowed and the dictionary is no longer accessible.
[compressed blocks]: #the-format-of-compressed_block
If a dictionary is provided by an external source,
it should be loaded with great care, its content considered untrusted.
ext/zstd/doc/zstd_manual.html view on Meta::CPAN
<BR></pre>
<pre><b>typedef ZSTD_CCtx ZSTD_CStream; </b>/**< CCtx and CStream are now effectively same object (>= v1.3.0) */<b>
</b></pre><BR>
<h3>ZSTD_CStream management functions</h3><pre></pre><b><pre>ZSTD_CStream* ZSTD_createCStream(void);
size_t ZSTD_freeCStream(ZSTD_CStream* zcs); </b>/* accept NULL pointer */<b>
</pre></b><BR>
<h3>Streaming compression functions</h3><pre></pre><b><pre>typedef enum {
ZSTD_e_continue=0, </b>/* collect more data, encoder decides when to output compressed result, for optimal compression ratio */<b>
ZSTD_e_flush=1, </b>/* flush any data provided so far,<b>
* it creates (at least) one new block, that can be decoded immediately on reception;
* frame will continue: any future data can still reference previously compressed data, improving compression.
* note : multithreaded compression will block to flush as much output as possible. */
ZSTD_e_end=2 </b>/* flush any remaining data _and_ close current frame.<b>
* note that frame is only closed after compressed data is fully flushed (return value == 0).
* After that point, any additional data starts a new frame.
* note : each frame is independent (does not reference any content from previous frame).
: note : multithreaded compression will block to flush as much output as possible. */
} ZSTD_EndDirective;
</pre></b><BR>
<pre><b>size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
ext/zstd/doc/zstd_manual.html view on Meta::CPAN
ZSTD_DStream objects can be re-used multiple times.
Use ZSTD_initDStream() to start a new decompression operation.
@return : recommended first input size
Alternatively, use advanced API to set specific properties.
Use ZSTD_decompressStream() repetitively to consume your input.
The function will update both `pos` fields.
If `input.pos < input.size`, some input has not been consumed.
It's up to the caller to present again remaining data.
The function tries to flush all data decoded immediately, respecting output buffer size.
If `output.pos < output.size`, decoder has flushed everything it could.
But if `output.pos == output.size`, there might be some data left within internal buffers.,
In which case, call ZSTD_decompressStream() again to flush whatever remains in the buffer.
Note : with no additional input provided, amount of data flushed is necessarily <= ZSTD_BLOCKSIZE_MAX.
@return : 0 when a frame is completely decoded and fully flushed,
or an error code, which can be tested using ZSTD_isError(),
or any other value > 0, which means there is still some decoding or flushing to do to complete current frame :
the return value is a suggested next input size (just a hint for better latency)
that will never request more than the remaining frame size.
<BR></pre>
<pre><b>typedef ZSTD_DCtx ZSTD_DStream; </b>/**< DCtx and DStream are now effectively same object (>= v1.3.0) */<b>
</b></pre><BR>
<h3>ZSTD_DStream management functions</h3><pre></pre><b><pre>ZSTD_DStream* ZSTD_createDStream(void);
ext/zstd/doc/zstd_manual.html view on Meta::CPAN
</b><p> Streaming decompression function.
Call repetitively to consume full input updating it as necessary.
Function will update both input and output `pos` fields exposing current state via these fields:
- `input.pos < input.size`, some input remaining and caller should provide remaining input
on the next call.
- `output.pos < output.size`, decoder finished and flushed all remaining buffers.
- `output.pos == output.size`, potentially uncflushed data present in the internal buffers,
call ZSTD_decompressStream() again to flush remaining data to output.
Note : with no additional input, amount of data flushed <= ZSTD_BLOCKSIZE_MAX.
@return : 0 when a frame is completely decoded and fully flushed,
or an error code, which can be tested using ZSTD_isError(),
or any other value > 0, which means there is some decoding or flushing to do to complete current frame.
</p></pre><BR>
<pre><b>size_t ZSTD_DStreamInSize(void); </b>/*!< recommended size for input buffer */<b>
</b></pre><BR>
<pre><b>size_t ZSTD_DStreamOutSize(void); </b>/*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */<b>
</b></pre><BR>
<a name="Chapter10"></a><h2>Simple dictionary API</h2><pre></pre>
ext/zstd/doc/zstd_manual.html view on Meta::CPAN
</p></pre><BR>
<pre><b>unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict);
</b><p> Provides the dictID of the dictionary loaded into `ddict`.
If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
Non-conformant dictionaries can still be loaded, but as content-only dictionaries.
</p></pre><BR>
<pre><b>unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
</b><p> Provides the dictID required to decompressed the frame stored within `src`.
If @return == 0, the dictID could not be decoded.
This could for one of the following reasons :
- The frame does not require a dictionary to be decoded (most common case).
- The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden piece of information.
Note : this use case also happens when using a non-conformant dictionary.
- `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
- This is not a Zstandard frame.
When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code.
</p></pre><BR>
<a name="Chapter13"></a><h2>Advanced dictionary and prefix API (Requires v1.4.0+)</h2><pre>
This API allows dictionaries to be used with ZSTD_compress2(),
ZSTD_compressStream2(), and ZSTD_decompressDCtx().
Dictionaries are sticky, they remain valid when same context is re-used,
they only reset when the context is reset
with ZSTD_reset_parameters or ZSTD_reset_session_and_parameters.
ext/zstd/doc/zstd_manual.html view on Meta::CPAN
or that previous contiguous segment is large enough to properly handle maximum back-reference distance.
There are multiple ways to guarantee this condition.
The most memory efficient way is to use a round buffer of sufficient size.
Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(),
which can return an error code if required value is too large for current system (in 32-bits mode).
In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one,
up to the moment there is not enough room left in the buffer to guarantee decoding another full block,
which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`.
At which point, decoding can resume from the beginning of the buffer.
Note that already decoded data stored in the buffer should be flushed before being overwritten.
There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory.
Finally, if you control the compression process, you can also ignore all buffer size rules,
as long as the encoder and decoder progress in "lock-step",
aka use exactly the same buffer sizes, break contiguity at the same place, etc.
Once buffers are setup, start decompression, with ZSTD_decompressBegin().
If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict().
Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail.
result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item.
It can also be an error code, which can be tested with ZSTD_isError().
A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
Context can then be reset to start a new decompression.
Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType().
This information is not required to properly decode a frame.
== Special case : skippable frames
Skippable frames allow integration of user-defined data into a flow of concatenated frames.
Skippable frames will be ignored (skipped) by decompressor.
The format of skippable frames is as follows :
ext/zstd/examples/dictionary_decompression.c view on Meta::CPAN
}
/* load dictionary only once */
const char* const dictName = argv[argc-1];
ZSTD_DDict* const dictPtr = createDict_orDie(dictName);
int u;
for (u=1; u<argc-1; u++) decompress(argv[u], dictPtr);
ZSTD_freeDDict(dictPtr);
printf("All %u files correctly decoded (in memory) \n", argc-2);
return 0;
}
ext/zstd/examples/simple_decompression.c view on Meta::CPAN
if (argc!=2) {
printf("wrong arguments\n");
printf("usage:\n");
printf("%s FILE\n", exeName);
return 1;
}
decompress(argv[1]);
printf("%s correctly decoded (in memory). \n", argv[1]);
return 0;
}
ext/zstd/lib/common/entropy_common.c view on Meta::CPAN
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
if (oSize >= hwSize) return ERROR(corruption_detected);
ip += 1;
{ U32 n;
for (n=0; n<oSize; n+=2) {
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
} } }
else { /* header compressed with FSE (normal case) */
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
/* max (hwSize-1) values decoded, as last one is implied */
oSize = FSE_decompress_wksp_bmi2(huffWeight, hwSize-1, ip+1, iSize, 6, workSpace, wkspSize, bmi2);
if (FSE_isError(oSize)) return oSize;
}
/* collect weight stats */
ZSTD_memset(rankStats, 0, (HUF_TABLELOG_MAX + 1) * sizeof(U32));
weightTotal = 0;
{ U32 n; for (n=0; n<oSize; n++) {
if (huffWeight[n] > HUF_TABLELOG_MAX) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
ext/zstd/lib/common/fse.h view on Meta::CPAN
The first thing to do is to init the bitStream.
errorCode = BIT_initDStream(&DStream, srcBuffer, srcSize);
You should then retrieve your initial state(s)
(in reverse flushing order if you have several ones) :
errorCode = FSE_initDState(&DState, &DStream, DTablePtr);
You can then decode your data, symbol after symbol.
For information the maximum number of bits read by FSE_decodeSymbol() is 'tableLog'.
Keep in mind that symbols are decoded in reverse order, like a LIFO stack (last in, first out).
unsigned char symbol = FSE_decodeSymbol(&DState, &DStream);
You can retrieve any bitfield you eventually stored into the bitStream (in reverse order)
Note : maximum allowed nbBits is 25, for 32-bits compatibility
size_t bitField = BIT_readBits(&DStream, nbBits);
All above operations only read from local register (which size depends on size_t).
Refueling the register from memory is manually performed by the reload method.
endSignal = FSE_reloadDStream(&DStream);
BIT_reloadDStream() result tells if there is still some more data to read from DStream.
BIT_DStream_unfinished : there is still some data left into the DStream.
BIT_DStream_endOfBuffer : Dstream reached end of buffer. Its container may no longer be completely filled.
BIT_DStream_completed : Dstream reached its exact end, corresponding in general to decompression completed.
BIT_DStream_tooFar : Dstream went too far. Decompression result is corrupted.
When reaching end of buffer (BIT_DStream_endOfBuffer), progress slowly, notably if you decode multiple symbols per loop,
to properly detect the exact end of stream.
After each decoded symbol, check if DStream is fully consumed using this simple test :
BIT_reloadDStream(&DStream) >= BIT_DStream_completed
When it's done, verify decompression is fully completed, by checking both DStream and the relevant states.
Checking if DStream has reached its end is performed by :
BIT_endOfDStream(&DStream);
Check also the states. There might be some symbols left there, if some high probability ones (>50%) are possible.
FSE_endOfDState(&DState);
*/
ext/zstd/lib/compress/zstd_compress.c view on Meta::CPAN
/* ZSTD_validateSequence() :
* @offCode : is presumed to follow format required by ZSTD_storeSeq()
* @returns a ZSTD error code if sequence is not valid
*/
static size_t
ZSTD_validateSequence(U32 offCode, U32 matchLength, U32 minMatch,
size_t posInSrc, U32 windowLog, size_t dictSize, int useSequenceProducer)
{
U32 const windowSize = 1u << windowLog;
/* posInSrc represents the amount of data the decoder would decode up to this point.
* As long as the amount of data decoded is less than or equal to window size, offsets may be
* larger than the total length of output decoded in order to reference the dict, even larger than
* window size. After output surpasses windowSize, we're limited to windowSize offsets again.
*/
size_t const offsetBound = posInSrc > windowSize ? (size_t)windowSize : posInSrc + (size_t)dictSize;
size_t const matchLenLowerBound = (minMatch == 3 || useSequenceProducer) ? 3 : 4;
RETURN_ERROR_IF(offCode > OFFSET_TO_OFFBASE(offsetBound), externalSequences_invalid, "Offset too large!");
/* Validate maxNbSeq is large enough for the given matchLength and minMatch */
RETURN_ERROR_IF(matchLength < matchLenLowerBound, externalSequences_invalid, "Matchlength too small for the minMatch");
return 0;
}
ext/zstd/lib/decompress/huf_decompress.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX1(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX1(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX1(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX1(op4, &bitD4, oend, dt, dtLog);
/* check */
{ U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endCheck) return ERROR(corruption_detected); }
/* decoded size */
return dstSize;
}
}
#if HUF_NEED_BMI2_FUNCTION
static BMI2_TARGET_ATTRIBUTE
size_t HUF_decompress4X1_usingDTable_internal_bmi2(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable) {
return HUF_decompress4X1_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
ext/zstd/lib/decompress/huf_decompress.c view on Meta::CPAN
segmentEnd += segmentSize;
else
segmentEnd = oend;
FORWARD_IF_ERROR(HUF_initRemainingDStream(&bit, &args, i, segmentEnd), "corruption");
/* Decompress and validate that we've produced exactly the expected length. */
args.op[i] += HUF_decodeStreamX1(args.op[i], &bit, segmentEnd, (HUF_DEltX1 const*)dt, HUF_DECODER_FAST_TABLELOG);
if (args.op[i] != segmentEnd) return ERROR(corruption_detected);
}
}
/* decoded size */
assert(dstSize != 0);
return dstSize;
}
HUF_DGEN(HUF_decompress1X1_usingDTable_internal)
static size_t HUF_decompress4X1_usingDTable_internal(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable, int flags)
{
HUF_DecompressUsingDTableFn fallbackFn = HUF_decompress4X1_usingDTable_internal_default;
ext/zstd/lib/decompress/huf_decompress.c view on Meta::CPAN
BYTE* const oend = ostart + dstSize;
const void* const dtPtr = DTable+1; /* force compiler to not use strict-aliasing */
const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
DTableDesc const dtd = HUF_getDTableDesc(DTable);
HUF_decodeStreamX2(ostart, &bitD, oend, dt, dtd.tableLog);
}
/* check */
if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
/* HUF_decompress4X2_usingDTable_internal_body():
* Conditions:
* @dstSize >= 6
*/
FORCE_INLINE_TEMPLATE size_t
HUF_decompress4X2_usingDTable_internal_body(
void* dst, size_t dstSize,
ext/zstd/lib/decompress/huf_decompress.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
/* check */
{ U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endCheck) return ERROR(corruption_detected); }
/* decoded size */
return dstSize;
}
}
#if HUF_NEED_BMI2_FUNCTION
static BMI2_TARGET_ATTRIBUTE
size_t HUF_decompress4X2_usingDTable_internal_bmi2(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable) {
return HUF_decompress4X2_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
ext/zstd/lib/decompress/huf_decompress.c view on Meta::CPAN
* struggle with codegen with high register pressure.
*/
{
int const index = (int)(bits[3] >> 53);
HUF_DEltX2 const entry = dtable[index];
MEM_write16(op[3], entry.sequence);
bits[3] <<= (entry.nbBits);
op[3] += (entry.length);
}
/* Reload the bistreams. The final bitstream must be reloaded
* after the 5th symbol was decoded.
*/
{
int const ctz = ZSTD_countTrailingZeros64(bits[stream]);
int const nbBits = ctz & 7;
int const nbBytes = ctz >> 3;
ip[stream] -= nbBytes;
bits[stream] = MEM_read64(ip[stream]) | 1;
bits[stream] <<= nbBits;
}
}
ext/zstd/lib/decompress/huf_decompress.c view on Meta::CPAN
segmentEnd += segmentSize;
else
segmentEnd = oend;
FORWARD_IF_ERROR(HUF_initRemainingDStream(&bit, &args, i, segmentEnd), "corruption");
args.op[i] += HUF_decodeStreamX2(args.op[i], &bit, segmentEnd, (HUF_DEltX2 const*)dt, HUF_DECODER_FAST_TABLELOG);
if (args.op[i] != segmentEnd)
return ERROR(corruption_detected);
}
}
/* decoded size */
return dstSize;
}
static size_t HUF_decompress4X2_usingDTable_internal(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable, int flags)
{
HUF_DecompressUsingDTableFn fallbackFn = HUF_decompress4X2_usingDTable_internal_default;
HUF_DecompressFastLoopFn loopFn = HUF_decompress4X2_usingDTable_internal_fast_c_loop;
#if DYNAMIC_BMI2
ext/zstd/lib/decompress/zstd_decompress.c view on Meta::CPAN
if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
RETURN_ERROR_IF(remainingSrcSize < frameHeaderSize+ZSTD_blockHeaderSize,
srcSize_wrong, "");
FORWARD_IF_ERROR( ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize) , "");
ip += frameHeaderSize; remainingSrcSize -= frameHeaderSize;
}
/* Loop on each block */
while (1) {
BYTE* oBlockEnd = oend;
size_t decodedSize;
blockProperties_t blockProperties;
size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSrcSize, &blockProperties);
if (ZSTD_isError(cBlockSize)) return cBlockSize;
ip += ZSTD_blockHeaderSize;
remainingSrcSize -= ZSTD_blockHeaderSize;
RETURN_ERROR_IF(cBlockSize > remainingSrcSize, srcSize_wrong, "");
if (ip >= op && ip < oBlockEnd) {
/* We are decompressing in-place. Limit the output pointer so that we
ext/zstd/lib/decompress/zstd_decompress.c view on Meta::CPAN
* ZSTD_decompressBlock_internal to never write past ip.
*
* See ZSTD_allocateLiteralsBuffer() for reference.
*/
oBlockEnd = op + (ip - op);
}
switch(blockProperties.blockType)
{
case bt_compressed:
decodedSize = ZSTD_decompressBlock_internal(dctx, op, (size_t)(oBlockEnd-op), ip, cBlockSize, /* frame */ 1, not_streaming);
break;
case bt_raw :
/* Use oend instead of oBlockEnd because this function is safe to overlap. It uses memmove. */
decodedSize = ZSTD_copyRawBlock(op, (size_t)(oend-op), ip, cBlockSize);
break;
case bt_rle :
decodedSize = ZSTD_setRleBlock(op, (size_t)(oBlockEnd-op), *ip, blockProperties.origSize);
break;
case bt_reserved :
default:
RETURN_ERROR(corruption_detected, "invalid block type");
}
if (ZSTD_isError(decodedSize)) return decodedSize;
if (dctx->validateChecksum)
XXH64_update(&dctx->xxhState, op, decodedSize);
if (decodedSize != 0)
op += decodedSize;
assert(ip != NULL);
ip += cBlockSize;
remainingSrcSize -= cBlockSize;
if (blockProperties.lastBlock) break;
}
if (dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) {
RETURN_ERROR_IF((U64)(op-ostart) != dctx->fParams.frameContentSize,
corruption_detected, "");
}
ext/zstd/lib/decompress/zstd_decompress.c view on Meta::CPAN
if (ddict) {
dict = ZSTD_DDict_dictContent(ddict);
dictSize = ZSTD_DDict_dictSize(ddict);
}
while (srcSize >= ZSTD_startingInputLength(dctx->format)) {
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
if (ZSTD_isLegacy(src, srcSize)) {
size_t decodedSize;
size_t const frameSize = ZSTD_findFrameCompressedSizeLegacy(src, srcSize);
if (ZSTD_isError(frameSize)) return frameSize;
RETURN_ERROR_IF(dctx->staticSize, memory_allocation,
"legacy support is not compatible with static dctx");
decodedSize = ZSTD_decompressLegacy(dst, dstCapacity, src, frameSize, dict, dictSize);
if (ZSTD_isError(decodedSize)) return decodedSize;
assert(decodedSize <= dstCapacity);
dst = (BYTE*)dst + decodedSize;
dstCapacity -= decodedSize;
src = (const BYTE*)src + frameSize;
srcSize -= frameSize;
continue;
}
#endif
if (srcSize >= 4) {
U32 const magicNumber = MEM_readLE32(src);
ext/zstd/lib/decompress/zstd_decompress.c view on Meta::CPAN
case bt_rle :
rSize = ZSTD_setRleBlock(dst, dstCapacity, *(const BYTE*)src, dctx->rleSize);
dctx->expected = 0; /* Streaming not supported */
break;
case bt_reserved : /* should never happen */
default:
RETURN_ERROR(corruption_detected, "invalid block type");
}
FORWARD_IF_ERROR(rSize, "");
RETURN_ERROR_IF(rSize > dctx->fParams.blockSizeMax, corruption_detected, "Decompressed Block Size Exceeds Maximum");
DEBUGLOG(5, "ZSTD_decompressContinue: decoded size from block : %u", (unsigned)rSize);
dctx->decodedSize += rSize;
if (dctx->validateChecksum) XXH64_update(&dctx->xxhState, dst, rSize);
dctx->previousDstEnd = (char*)dst + rSize;
/* Stay on the same stage until we are finished streaming the block. */
if (dctx->expected > 0) {
return rSize;
}
if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of frame */
DEBUGLOG(4, "ZSTD_decompressContinue: decoded size from frame : %u", (unsigned)dctx->decodedSize);
RETURN_ERROR_IF(
dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN
&& dctx->decodedSize != dctx->fParams.frameContentSize,
corruption_detected, "");
if (dctx->fParams.checksumFlag) { /* another round for frame checksum */
dctx->expected = 4;
dctx->stage = ZSTDds_checkChecksum;
} else {
ZSTD_DCtx_trace_end(dctx, dctx->decodedSize, dctx->processedCSize, /* streaming */ 1);
dctx->expected = 0; /* ends here */
dctx->stage = ZSTDds_getFrameHeaderSize;
}
} else {
dctx->stage = ZSTDds_decodeBlockHeader;
dctx->expected = ZSTD_blockHeaderSize;
}
return rSize;
}
case ZSTDds_checkChecksum:
assert(srcSize == 4); /* guaranteed by dctx->expected */
{
if (dctx->validateChecksum) {
U32 const h32 = (U32)XXH64_digest(&dctx->xxhState);
U32 const check32 = MEM_readLE32(src);
DEBUGLOG(4, "ZSTD_decompressContinue: checksum : calculated %08X :: %08X read", (unsigned)h32, (unsigned)check32);
RETURN_ERROR_IF(check32 != h32, checksum_wrong, "");
}
ZSTD_DCtx_trace_end(dctx, dctx->decodedSize, dctx->processedCSize, /* streaming */ 1);
dctx->expected = 0;
dctx->stage = ZSTDds_getFrameHeaderSize;
return 0;
}
case ZSTDds_decodeSkippableHeader:
assert(src != NULL);
assert(srcSize <= ZSTD_SKIPPABLEHEADERSIZE);
ZSTD_memcpy(dctx->headerBuffer + (ZSTD_SKIPPABLEHEADERSIZE - srcSize), src, srcSize); /* complete skippable header */
dctx->expected = MEM_readLE32(dctx->headerBuffer + ZSTD_FRAMEIDSIZE); /* note : dctx->expected can grow seriously large, beyond local buffer size */
ext/zstd/lib/decompress/zstd_decompress.c view on Meta::CPAN
size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx)
{
assert(dctx != NULL);
#if ZSTD_TRACE
dctx->traceCtx = (ZSTD_trace_decompress_begin != NULL) ? ZSTD_trace_decompress_begin(dctx) : 0;
#endif
dctx->expected = ZSTD_startingInputLength(dctx->format); /* dctx->format must be properly set */
dctx->stage = ZSTDds_getFrameHeaderSize;
dctx->processedCSize = 0;
dctx->decodedSize = 0;
dctx->previousDstEnd = NULL;
dctx->prefixStart = NULL;
dctx->virtualStart = NULL;
dctx->dictEnd = NULL;
dctx->entropy.hufTable[0] = (HUF_DTable)((ZSTD_HUFFDTABLE_CAPACITY_LOG)*0x1000001); /* cover both little and big endian */
dctx->litEntropy = dctx->fseEntropy = 0;
dctx->dictID = 0;
dctx->bType = bt_reserved;
ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue));
ZSTD_memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue)); /* initial repcodes */
ext/zstd/lib/decompress/zstd_decompress.c view on Meta::CPAN
* It can still be loaded, but as a content-only dictionary. */
unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize)
{
if (dictSize < 8) return 0;
if (MEM_readLE32(dict) != ZSTD_MAGIC_DICTIONARY) return 0;
return MEM_readLE32((const char*)dict + ZSTD_FRAMEIDSIZE);
}
/*! ZSTD_getDictID_fromFrame() :
* Provides the dictID required to decompress frame stored within `src`.
* If @return == 0, the dictID could not be decoded.
* This could for one of the following reasons :
* - The frame does not require a dictionary (most common case).
* - The frame was built with dictID intentionally removed.
* Needed dictionary is a hidden piece of information.
* Note : this use case also happens when using a non-conformant dictionary.
* - `srcSize` is too small, and as a result, frame header could not be decoded.
* Note : possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`.
* - This is not a Zstandard frame.
* When identifying the exact failure cause, it's possible to use
* ZSTD_getFrameHeader(), which will provide a more precise error code. */
unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize)
{
ZSTD_frameHeader zfp = { 0, 0, 0, ZSTD_frame, 0, 0, 0, 0, 0 };
size_t const hError = ZSTD_getFrameHeader(&zfp, src, srcSize);
if (ZSTD_isError(hError)) return 0;
return zfp.dictID;
ext/zstd/lib/decompress/zstd_decompress.c view on Meta::CPAN
* and updates the stage and the output buffer state. This call is extracted so it can be
* used both when reading directly from the ZSTD_inBuffer, and in buffered input mode.
* NOTE: You must break after calling this function since the streamStage is modified.
*/
static size_t ZSTD_decompressContinueStream(
ZSTD_DStream* zds, char** op, char* oend,
void const* src, size_t srcSize) {
int const isSkipFrame = ZSTD_isSkipFrame(zds);
if (zds->outBufferMode == ZSTD_bm_buffered) {
size_t const dstSize = isSkipFrame ? 0 : zds->outBuffSize - zds->outStart;
size_t const decodedSize = ZSTD_decompressContinue(zds,
zds->outBuff + zds->outStart, dstSize, src, srcSize);
FORWARD_IF_ERROR(decodedSize, "");
if (!decodedSize && !isSkipFrame) {
zds->streamStage = zdss_read;
} else {
zds->outEnd = zds->outStart + decodedSize;
zds->streamStage = zdss_flush;
}
} else {
/* Write directly into the output buffer */
size_t const dstSize = isSkipFrame ? 0 : (size_t)(oend - *op);
size_t const decodedSize = ZSTD_decompressContinue(zds, *op, dstSize, src, srcSize);
FORWARD_IF_ERROR(decodedSize, "");
*op += decodedSize;
/* Flushing is not needed. */
zds->streamStage = zdss_read;
assert(*op <= oend);
assert(zds->outBufferMode == ZSTD_bm_stable);
}
return 0;
}
size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
{
ext/zstd/lib/decompress/zstd_decompress.c view on Meta::CPAN
zds->noForwardProgress ++;
if (zds->noForwardProgress >= ZSTD_NO_FORWARD_PROGRESS_MAX) {
RETURN_ERROR_IF(op==oend, noForwardProgress_destFull, "");
RETURN_ERROR_IF(ip==iend, noForwardProgress_inputEmpty, "");
assert(0);
}
} else {
zds->noForwardProgress = 0;
}
{ size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zds);
if (!nextSrcSizeHint) { /* frame fully decoded */
if (zds->outEnd == zds->outStart) { /* output fully flushed */
if (zds->hostageByte) {
if (input->pos >= input->size) {
/* can't release hostage (not present) */
zds->streamStage = zdss_read;
return 1;
}
input->pos++; /* release hostage */
} /* zds->hostageByte */
return 0;
ext/zstd/lib/decompress/zstd_decompress_internal.h view on Meta::CPAN
const HUF_DTable* HUFptr;
ZSTD_entropyDTables_t entropy;
U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */
const void* previousDstEnd; /* detect continuity */
const void* prefixStart; /* start of current segment */
const void* virtualStart; /* virtual start of previous segment if it was just before current one */
const void* dictEnd; /* end of previous segment */
size_t expected;
ZSTD_frameHeader fParams;
U64 processedCSize;
U64 decodedSize;
blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
ZSTD_dStage stage;
U32 litEntropy;
U32 fseEntropy;
XXH64_state_t xxhState;
size_t headerSize;
ZSTD_format_e format;
ZSTD_forceIgnoreChecksum_e forceIgnoreChecksum; /* User specified: if == 1, will ignore checksums in compressed frame. Default == 0 */
U32 validateChecksum; /* if == 1, will validate checksum. Is == 1 if (fParams.checksumFlag == 1) and (forceIgnoreChecksum == 0). */
const BYTE* litPtr;
ext/zstd/lib/deprecated/zbuff.h view on Meta::CPAN
#endif /* ZBUFF_DISABLE_DEPRECATE_WARNINGS */
/* *************************************
* Streaming functions
***************************************/
/* This is the easier "buffered" streaming API,
* using an internal buffer to lift all restrictions on user-provided buffers
* which can be any size, any place, for both input and output.
* ZBUFF and ZSTD are 100% interoperable,
* frames created by one can be decoded by the other one */
typedef ZSTD_CStream ZBUFF_CCtx;
ZBUFF_DEPRECATED("use ZSTD_createCStream") ZBUFF_CCtx* ZBUFF_createCCtx(void);
ZBUFF_DEPRECATED("use ZSTD_freeCStream") size_t ZBUFF_freeCCtx(ZBUFF_CCtx* cctx);
ZBUFF_DEPRECATED("use ZSTD_initCStream") size_t ZBUFF_compressInit(ZBUFF_CCtx* cctx, int compressionLevel);
ZBUFF_DEPRECATED("use ZSTD_initCStream_usingDict") size_t ZBUFF_compressInitDictionary(ZBUFF_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel);
ZBUFF_DEPRECATED("use ZSTD_compressStream") size_t ZBUFF_compressContinue(ZBUFF_CCtx* cctx, void* dst, size_t* dstCapacityPtr, const void* src, size_t* srcSizePtr);
ZBUFF_DEPRECATED("use ZSTD_flushStream") size_t ZBUFF_compressFlush(ZBUFF_CCtx* cctx, void* dst, size_t* dstCapacityPtr);
ext/zstd/lib/deprecated/zbuff.h view on Meta::CPAN
* Use ZBUFF_createDCtx() and ZBUFF_freeDCtx() to create/release resources.
* Use ZBUFF_decompressInit() to start a new decompression operation,
* or ZBUFF_decompressInitDictionary() if decompression requires a dictionary.
* Note that ZBUFF_DCtx objects can be re-init multiple times.
*
* Use ZBUFF_decompressContinue() repetitively to consume your input.
* *srcSizePtr and *dstCapacityPtr can be any size.
* The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
* Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
* The content of `dst` will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters, or change `dst`.
* @return : 0 when a frame is completely decoded and fully flushed,
* 1 when there is still some data left within internal buffer to flush,
* >1 when more data is expected, with value being a suggested next input size (it's just a hint, which helps latency),
* or an error code, which can be tested using ZBUFF_isError().
*
* Hint : recommended buffer sizes (not compulsory) : ZBUFF_recommendedDInSize() and ZBUFF_recommendedDOutSize()
* output : ZBUFF_recommendedDOutSize== 128 KB block size is the internal unit, it ensures it's always possible to write a full block when decoded.
* input : ZBUFF_recommendedDInSize == 128KB + 3;
* just follow indications from ZBUFF_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
* *******************************************************************************/
/* *************************************
* Tool functions
***************************************/
ZBUFF_DEPRECATED("use ZSTD_isError") unsigned ZBUFF_isError(size_t errorCode);
ZBUFF_DEPRECATED("use ZSTD_getErrorName") const char* ZBUFF_getErrorName(size_t errorCode);
ext/zstd/lib/legacy/zstd_legacy.h view on Meta::CPAN
case 3 :
(void)legacyContext; (void)output; (void)input;
return ERROR(version_unsupported);
#if (ZSTD_LEGACY_SUPPORT <= 4)
case 4 :
{
ZBUFFv04_DCtx* dctx = (ZBUFFv04_DCtx*) legacyContext;
const void* src = (const char*)input->src + input->pos;
size_t readSize = input->size - input->pos;
void* dst = (char*)output->dst + output->pos;
size_t decodedSize = output->size - output->pos;
size_t const hintSize = ZBUFFv04_decompressContinue(dctx, dst, &decodedSize, src, &readSize);
output->pos += decodedSize;
input->pos += readSize;
return hintSize;
}
#endif
#if (ZSTD_LEGACY_SUPPORT <= 5)
case 5 :
{
ZBUFFv05_DCtx* dctx = (ZBUFFv05_DCtx*) legacyContext;
const void* src = (const char*)input->src + input->pos;
size_t readSize = input->size - input->pos;
void* dst = (char*)output->dst + output->pos;
size_t decodedSize = output->size - output->pos;
size_t const hintSize = ZBUFFv05_decompressContinue(dctx, dst, &decodedSize, src, &readSize);
output->pos += decodedSize;
input->pos += readSize;
return hintSize;
}
#endif
#if (ZSTD_LEGACY_SUPPORT <= 6)
case 6 :
{
ZBUFFv06_DCtx* dctx = (ZBUFFv06_DCtx*) legacyContext;
const void* src = (const char*)input->src + input->pos;
size_t readSize = input->size - input->pos;
void* dst = (char*)output->dst + output->pos;
size_t decodedSize = output->size - output->pos;
size_t const hintSize = ZBUFFv06_decompressContinue(dctx, dst, &decodedSize, src, &readSize);
output->pos += decodedSize;
input->pos += readSize;
return hintSize;
}
#endif
#if (ZSTD_LEGACY_SUPPORT <= 7)
case 7 :
{
ZBUFFv07_DCtx* dctx = (ZBUFFv07_DCtx*) legacyContext;
const void* src = (const char*)input->src + input->pos;
size_t readSize = input->size - input->pos;
void* dst = (char*)output->dst + output->pos;
size_t decodedSize = output->size - output->pos;
size_t const hintSize = ZBUFFv07_decompressContinue(dctx, dst, &decodedSize, src, &readSize);
output->pos += decodedSize;
input->pos += readSize;
return hintSize;
}
#endif
}
}
#if defined (__cplusplus)
}
ext/zstd/lib/legacy/zstd_v01.c view on Meta::CPAN
for (n=0; n<oSize; n+=2)
{
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
}
}
}
else /* header compressed with FSE (normal case) */
{
if (iSize+1 > srcSize) return (size_t)-FSE_ERROR_srcSize_wrong;
oSize = FSE_decompress(huffWeight, HUF_MAX_SYMBOL_VALUE, ip+1, iSize); /* max 255 values decoded, last one is implied */
if (FSE_isError(oSize)) return oSize;
}
/* collect weight stats */
memset(rankVal, 0, sizeof(rankVal));
weightTotal = 0;
for (n=0; n<oSize; n++)
{
if (huffWeight[n] >= HUF_ABSOLUTEMAX_TABLELOG) return (size_t)-FSE_ERROR_corruptionDetected;
rankVal[huffWeight[n]]++;
ext/zstd/lib/legacy/zstd_v01.c view on Meta::CPAN
if (rleSize > 0) {
memset(oend - rleSize, *ip, rleSize);
}
*litStart = oend - rleSize;
*litSize = rleSize;
ip++;
break;
}
case bt_compressed:
{
size_t decodedLitSize = ZSTD_decompressLiterals(ctx, dst, maxDstSize, ip, litcSize);
if (ZSTDv01_isError(decodedLitSize)) return decodedLitSize;
*litStart = oend - decodedLitSize;
*litSize = decodedLitSize;
ip += litcSize;
break;
}
case bt_end:
default:
return ERROR(GENERIC);
}
return ip-istart;
}
ext/zstd/lib/legacy/zstd_v01.h view on Meta::CPAN
***************************************/
size_t ZSTDv01_resetDCtx(ZSTDv01_Dctx* dctx);
size_t ZSTDv01_nextSrcSizeToDecompress(ZSTDv01_Dctx* dctx);
size_t ZSTDv01_decompressContinue(ZSTDv01_Dctx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
/**
Use above functions alternatively.
ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block.
Result is the number of bytes regenerated within 'dst'.
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
*/
/* *************************************
* Prefix - version detection
***************************************/
#define ZSTDv01_magicNumber 0xFD2FB51E /* Big Endian version */
#define ZSTDv01_magicNumberLE 0x1EB52FFD /* Little Endian version */
#if defined (__cplusplus)
ext/zstd/lib/legacy/zstd_v02.c view on Meta::CPAN
* Streaming functions
***************************************/
typedef struct ZSTD_DCtx_s ZSTD_DCtx;
/*
Use above functions alternatively.
ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block.
Result is the number of bytes regenerated within 'dst'.
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
*/
/* *************************************
* Prefix - version detection
***************************************/
#define ZSTD_magicNumber 0xFD2FB522 /* v0.2 (current)*/
#if defined (__cplusplus)
}
ext/zstd/lib/legacy/zstd_v02.c view on Meta::CPAN
for (n=0; n<oSize; n+=2)
{
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
}
}
}
else /* header compressed with FSE (normal case) */
{
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
oSize = FSE_decompress(huffWeight, hwSize-1, ip+1, iSize); /* max (hwSize-1) values decoded, as last one is implied */
if (FSE_isError(oSize)) return oSize;
}
/* collect weight stats */
memset(rankStats, 0, (HUF_ABSOLUTEMAX_TABLELOG + 1) * sizeof(U32));
weightTotal = 0;
for (n=0; n<oSize; n++)
{
if (huffWeight[n] >= HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
ext/zstd/lib/legacy/zstd_v02.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
static size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUF_CREATE_STATIC_DTABLEX2(DTable, HUF_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
size_t errorCode;
ext/zstd/lib/legacy/zstd_v02.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX4(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
static size_t HUF_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUF_CREATE_STATIC_DTABLEX4(DTable, HUF_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
ext/zstd/lib/legacy/zstd_v02.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX6(op1, &bitD1, opStart2, DTable, dtLog);
HUF_decodeStreamX6(op2, &bitD2, opStart3, DTable, dtLog);
HUF_decodeStreamX6(op3, &bitD3, opStart4, DTable, dtLog);
HUF_decodeStreamX6(op4, &bitD4, oend, DTable, dtLog);
/* check */
endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
static size_t HUF_decompress4X6 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUF_CREATE_STATIC_DTABLEX6(DTable, HUF_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
ext/zstd/lib/legacy/zstd_v02.c view on Meta::CPAN
/* Frame Header */
if (srcSize < ZSTD_frameHeaderSize+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
magicNumber = MEM_readLE32(src);
if (magicNumber != ZSTD_magicNumber) return ERROR(prefix_unknown);
ip += ZSTD_frameHeaderSize; remainingSize -= ZSTD_frameHeaderSize;
/* Loop on each block */
while (1)
{
size_t decodedSize=0;
size_t cBlockSize = ZSTD_getcBlockSize(ip, iend-ip, &blockProperties);
if (ZSTD_isError(cBlockSize)) return cBlockSize;
ip += ZSTD_blockHeaderSize;
remainingSize -= ZSTD_blockHeaderSize;
if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
switch(blockProperties.blockType)
{
case bt_compressed:
decodedSize = ZSTD_decompressBlock(ctx, op, oend-op, ip, cBlockSize);
break;
case bt_raw :
decodedSize = ZSTD_copyUncompressedBlock(op, oend-op, ip, cBlockSize);
break;
case bt_rle :
return ERROR(GENERIC); /* not yet supported */
break;
case bt_end :
/* end of frame */
if (remainingSize) return ERROR(srcSize_wrong);
break;
default:
return ERROR(GENERIC); /* impossible */
}
if (cBlockSize == 0) break; /* bt_end */
if (ZSTD_isError(decodedSize)) return decodedSize;
op += decodedSize;
ip += cBlockSize;
remainingSize -= cBlockSize;
}
return op-ostart;
}
static size_t ZSTD_decompress(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
ZSTD_DCtx ctx;
ext/zstd/lib/legacy/zstd_v02.h view on Meta::CPAN
***************************************/
size_t ZSTDv02_resetDCtx(ZSTDv02_Dctx* dctx);
size_t ZSTDv02_nextSrcSizeToDecompress(ZSTDv02_Dctx* dctx);
size_t ZSTDv02_decompressContinue(ZSTDv02_Dctx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
/**
Use above functions alternatively.
ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block.
Result is the number of bytes regenerated within 'dst'.
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
*/
/* *************************************
* Prefix - version detection
***************************************/
#define ZSTDv02_magicNumber 0xFD2FB522 /* v0.2 */
#if defined (__cplusplus)
}
ext/zstd/lib/legacy/zstd_v03.c view on Meta::CPAN
* Streaming functions
***************************************/
typedef struct ZSTD_DCtx_s ZSTD_DCtx;
/*
Use above functions alternatively.
ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block.
Result is the number of bytes regenerated within 'dst'.
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
*/
/* *************************************
* Prefix - version detection
***************************************/
#define ZSTD_magicNumber 0xFD2FB523 /* v0.3 */
#if defined (__cplusplus)
}
ext/zstd/lib/legacy/zstd_v03.c view on Meta::CPAN
for (n=0; n<oSize; n+=2)
{
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
}
}
}
else /* header compressed with FSE (normal case) */
{
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
oSize = FSE_decompress(huffWeight, hwSize-1, ip+1, iSize); /* max (hwSize-1) values decoded, as last one is implied */
if (FSE_isError(oSize)) return oSize;
}
/* collect weight stats */
memset(rankStats, 0, (HUF_ABSOLUTEMAX_TABLELOG + 1) * sizeof(U32));
weightTotal = 0;
for (n=0; n<oSize; n++)
{
if (huffWeight[n] >= HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
ext/zstd/lib/legacy/zstd_v03.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
static size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUF_CREATE_STATIC_DTABLEX2(DTable, HUF_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
size_t errorCode;
ext/zstd/lib/legacy/zstd_v03.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX4(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
static size_t HUF_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUF_CREATE_STATIC_DTABLEX4(DTable, HUF_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
ext/zstd/lib/legacy/zstd_v03.c view on Meta::CPAN
/* Frame Header */
if (srcSize < ZSTD_frameHeaderSize+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
magicNumber = MEM_readLE32(src);
if (magicNumber != ZSTD_magicNumber) return ERROR(prefix_unknown);
ip += ZSTD_frameHeaderSize; remainingSize -= ZSTD_frameHeaderSize;
/* Loop on each block */
while (1)
{
size_t decodedSize=0;
size_t cBlockSize = ZSTD_getcBlockSize(ip, iend-ip, &blockProperties);
if (ZSTD_isError(cBlockSize)) return cBlockSize;
ip += ZSTD_blockHeaderSize;
remainingSize -= ZSTD_blockHeaderSize;
if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
switch(blockProperties.blockType)
{
case bt_compressed:
decodedSize = ZSTD_decompressBlock(ctx, op, oend-op, ip, cBlockSize);
break;
case bt_raw :
decodedSize = ZSTD_copyUncompressedBlock(op, oend-op, ip, cBlockSize);
break;
case bt_rle :
return ERROR(GENERIC); /* not yet supported */
break;
case bt_end :
/* end of frame */
if (remainingSize) return ERROR(srcSize_wrong);
break;
default:
return ERROR(GENERIC); /* impossible */
}
if (cBlockSize == 0) break; /* bt_end */
if (ZSTD_isError(decodedSize)) return decodedSize;
op += decodedSize;
ip += cBlockSize;
remainingSize -= cBlockSize;
}
return op-ostart;
}
static size_t ZSTD_decompress(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
ZSTD_DCtx ctx;
ext/zstd/lib/legacy/zstd_v03.h view on Meta::CPAN
***************************************/
size_t ZSTDv03_resetDCtx(ZSTDv03_Dctx* dctx);
size_t ZSTDv03_nextSrcSizeToDecompress(ZSTDv03_Dctx* dctx);
size_t ZSTDv03_decompressContinue(ZSTDv03_Dctx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
/**
Use above functions alternatively.
ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block.
Result is the number of bytes regenerated within 'dst'.
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
*/
/* *************************************
* Prefix - version detection
***************************************/
#define ZSTDv03_magicNumber 0xFD2FB523 /* v0.3 */
#if defined (__cplusplus)
}
ext/zstd/lib/legacy/zstd_v04.c view on Meta::CPAN
This operation must mimic the compressor behavior, otherwise decompression will fail or be corrupted.
Then it's possible to start decompression.
Use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() requires this exact amount of bytes, or it will fail.
ZSTD_decompressContinue() needs previous data blocks during decompression, up to (1 << windowlog).
They should preferably be located contiguously, prior to current block. Alternatively, a round buffer is also possible.
@result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst'.
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
Context can then be reset to start a new decompression.
*/
#endif /* ZSTD_STATIC_H */
/*
ext/zstd/lib/legacy/zstd_v04.c view on Meta::CPAN
for (n=0; n<oSize; n+=2)
{
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
}
}
}
else /* header compressed with FSE (normal case) */
{
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
oSize = FSE_decompress(huffWeight, hwSize-1, ip+1, iSize); /* max (hwSize-1) values decoded, as last one is implied */
if (FSE_isError(oSize)) return oSize;
}
/* collect weight stats */
memset(rankStats, 0, (HUF_ABSOLUTEMAX_TABLELOG + 1) * sizeof(U32));
weightTotal = 0;
for (n=0; n<oSize; n++)
{
if (huffWeight[n] >= HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
ext/zstd/lib/legacy/zstd_v04.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
static size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUF_CREATE_STATIC_DTABLEX2(DTable, HUF_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
size_t errorCode;
ext/zstd/lib/legacy/zstd_v04.c view on Meta::CPAN
/* finish bitStreams one by one */
HUF_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX4(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
static size_t HUF_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUF_CREATE_STATIC_DTABLEX4(DTable, HUF_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
ext/zstd/lib/legacy/zstd_v04.c view on Meta::CPAN
if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
if (srcSize < frameHeaderSize+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
ip += frameHeaderSize; remainingSize -= frameHeaderSize;
frameHeaderSize = ZSTD_decodeFrameHeader_Part2(ctx, src, frameHeaderSize);
if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
}
/* Loop on each block */
while (1)
{
size_t decodedSize=0;
size_t cBlockSize = ZSTD_getcBlockSize(ip, iend-ip, &blockProperties);
if (ZSTD_isError(cBlockSize)) return cBlockSize;
ip += ZSTD_blockHeaderSize;
remainingSize -= ZSTD_blockHeaderSize;
if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
switch(blockProperties.blockType)
{
case bt_compressed:
decodedSize = ZSTD_decompressBlock_internal(ctx, op, oend-op, ip, cBlockSize);
break;
case bt_raw :
decodedSize = ZSTD_copyRawBlock(op, oend-op, ip, cBlockSize);
break;
case bt_rle :
return ERROR(GENERIC); /* not yet supported */
break;
case bt_end :
/* end of frame */
if (remainingSize) return ERROR(srcSize_wrong);
break;
default:
return ERROR(GENERIC); /* impossible */
}
if (cBlockSize == 0) break; /* bt_end */
if (ZSTD_isError(decodedSize)) return decodedSize;
op += decodedSize;
ip += cBlockSize;
remainingSize -= cBlockSize;
}
return op-ostart;
}
/* ZSTD_errorFrameSizeInfoLegacy() :
assumes `cSize` and `dBound` are _not_ NULL */
static void ZSTD_errorFrameSizeInfoLegacy(size_t* cSize, unsigned long long* dBound, size_t ret)
ext/zstd/lib/legacy/zstd_v04.c view on Meta::CPAN
* Use ZBUFF_createDCtx() and ZBUFF_freeDCtx() to create/release resources.
* Use ZBUFF_decompressInit() to start a new decompression operation.
* ZBUFF_DCtx objects can be reused multiple times.
*
* Use ZBUFF_decompressContinue() repetitively to consume your input.
* *srcSizePtr and *maxDstSizePtr can be any size.
* The function will report how many bytes were read or written by modifying *srcSizePtr and *maxDstSizePtr.
* Note that it may not consume the entire input, in which case it's up to the caller to call again the function with remaining input.
* The content of dst will be overwritten (up to *maxDstSizePtr) at each function call, so save its content if it matters or change dst .
* return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to improve latency)
* or 0 when a frame is completely decoded
* or an error code, which can be tested using ZBUFF_isError().
*
* Hint : recommended buffer sizes (not compulsory)
* output : 128 KB block size is the internal unit, it ensures it's always possible to write a full block when it's decoded.
* input : just follow indications from ZBUFF_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
* **************************************************/
typedef enum { ZBUFFds_init, ZBUFFds_readHeader, ZBUFFds_loadHeader, ZBUFFds_decodeHeader,
ZBUFFds_read, ZBUFFds_load, ZBUFFds_flush } ZBUFF_dStage;
/* *** Resource management *** */
#define ZSTD_frameHeaderSize_max 5 /* too magical, should come from reference */
struct ZBUFFv04_DCtx_s {
ext/zstd/lib/legacy/zstd_v04.c view on Meta::CPAN
size_t neededInSize = ZSTD_nextSrcSizeToDecompress(zbc->zc);
if (neededInSize==0) /* end of frame */
{
zbc->stage = ZBUFFds_init;
notDone = 0;
break;
}
if ((size_t)(iend-ip) >= neededInSize)
{
/* directly decode from src */
size_t decodedSize = ZSTD_decompressContinue(zbc->zc,
zbc->outBuff + zbc->outStart, zbc->outBuffSize - zbc->outStart,
ip, neededInSize);
if (ZSTD_isError(decodedSize)) return decodedSize;
ip += neededInSize;
if (!decodedSize) break; /* this was just a header */
zbc->outEnd = zbc->outStart + decodedSize;
zbc->stage = ZBUFFds_flush;
break;
}
if (ip==iend) { notDone = 0; break; } /* no more input */
zbc->stage = ZBUFFds_load;
}
/* fall-through */
case ZBUFFds_load:
{
size_t neededInSize = ZSTD_nextSrcSizeToDecompress(zbc->zc);
size_t toLoad = neededInSize - zbc->inPos; /* should always be <= remaining space within inBuff */
size_t loadedSize;
if (toLoad > zbc->inBuffSize - zbc->inPos) return ERROR(corruption_detected); /* should never happen */
loadedSize = ZBUFF_limitCopy(zbc->inBuff + zbc->inPos, toLoad, ip, iend-ip);
ip += loadedSize;
zbc->inPos += loadedSize;
if (loadedSize < toLoad) { notDone = 0; break; } /* not enough input, wait for more */
{
size_t decodedSize = ZSTD_decompressContinue(zbc->zc,
zbc->outBuff + zbc->outStart, zbc->outBuffSize - zbc->outStart,
zbc->inBuff, neededInSize);
if (ZSTD_isError(decodedSize)) return decodedSize;
zbc->inPos = 0; /* input is consumed */
if (!decodedSize) { zbc->stage = ZBUFFds_read; break; } /* this was just a header */
zbc->outEnd = zbc->outStart + decodedSize;
zbc->stage = ZBUFFds_flush;
/* ZBUFFds_flush follows */
}
}
/* fall-through */
case ZBUFFds_flush:
{
size_t toFlushSize = zbc->outEnd - zbc->outStart;
size_t flushedSize = ZBUFF_limitCopy(op, oend-op, zbc->outBuff + zbc->outStart, toFlushSize);
op += flushedSize;
ext/zstd/lib/legacy/zstd_v04.h view on Meta::CPAN
***************************************/
size_t ZSTDv04_resetDCtx(ZSTDv04_Dctx* dctx);
size_t ZSTDv04_nextSrcSizeToDecompress(ZSTDv04_Dctx* dctx);
size_t ZSTDv04_decompressContinue(ZSTDv04_Dctx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
/**
Use above functions alternatively.
ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block.
Result is the number of bytes regenerated within 'dst'.
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
*/
/* *************************************
* Buffered Streaming
***************************************/
typedef struct ZBUFFv04_DCtx_s ZBUFFv04_DCtx;
ZBUFFv04_DCtx* ZBUFFv04_createDCtx(void);
size_t ZBUFFv04_freeDCtx(ZBUFFv04_DCtx* dctx);
ext/zstd/lib/legacy/zstd_v04.h view on Meta::CPAN
* Optionally, a reference to a static dictionary can be set, using ZBUFF_decompressWithDictionary()
* It must be the same content as the one set during compression phase.
* Dictionary content must remain accessible during the decompression process.
*
* Use ZBUFF_decompressContinue() repetitively to consume your input.
* *srcSizePtr and *maxDstSizePtr can be any size.
* The function will report how many bytes were read or written by modifying *srcSizePtr and *maxDstSizePtr.
* Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
* The content of dst will be overwritten (up to *maxDstSizePtr) at each function call, so save its content if it matters or change dst.
* @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to improve latency)
* or 0 when a frame is completely decoded
* or an error code, which can be tested using ZBUFF_isError().
*
* Hint : recommended buffer sizes (not compulsory) : ZBUFF_recommendedDInSize / ZBUFF_recommendedDOutSize
* output : ZBUFF_recommendedDOutSize==128 KB block size is the internal unit, it ensures it's always possible to write a full block when it's decoded.
* input : ZBUFF_recommendedDInSize==128Kb+3; just follow indications from ZBUFF_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
* **************************************************/
unsigned ZBUFFv04_isError(size_t errorCode);
const char* ZBUFFv04_getErrorName(size_t errorCode);
/** The below functions provide recommended buffer sizes for Compression or Decompression operations.
* These sizes are not compulsory, they just tend to offer better latency */
size_t ZBUFFv04_recommendedDInSize(void);
size_t ZBUFFv04_recommendedDOutSize(void);
ext/zstd/lib/legacy/zstd_v05.c view on Meta::CPAN
Start decompression, with ZSTDv05_decompressBegin() or ZSTDv05_decompressBegin_usingDict()
Alternatively, you can copy a prepared context, using ZSTDv05_copyDCtx()
Then use ZSTDv05_nextSrcSizeToDecompress() and ZSTDv05_decompressContinue() alternatively.
ZSTDv05_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTDv05_decompressContinue().
ZSTDv05_decompressContinue() requires this exact amount of bytes, or it will fail.
ZSTDv05_decompressContinue() needs previous data blocks during decompression, up to (1 << windowlog).
They should preferably be located contiguously, prior to current block. Alternatively, a round buffer is also possible.
@result of ZSTDv05_decompressContinue() is the number of bytes regenerated within 'dst'.
It can be zero, which is not an error; it just means ZSTDv05_decompressContinue() has decoded some header.
A frame is fully decoded when ZSTDv05_nextSrcSizeToDecompress() returns zero.
Context can then be reset to start a new decompression.
*/
/* **************************************
* Block functions
****************************************/
/*! Block functions produce and decode raw zstd blocks, without frame metadata.
User will have to take in charge required information to regenerate data, such as block sizes.
ext/zstd/lib/legacy/zstd_v05.c view on Meta::CPAN
iSize = ((oSize+1)/2);
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
if (oSize >= hwSize) return ERROR(corruption_detected);
ip += 1;
for (n=0; n<oSize; n+=2) {
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
} } }
else { /* header compressed with FSEv05 (normal case) */
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
oSize = FSEv05_decompress(huffWeight, hwSize-1, ip+1, iSize); /* max (hwSize-1) values decoded, as last one is implied */
if (FSEv05_isError(oSize)) return oSize;
}
/* collect weight stats */
memset(rankStats, 0, (HUFv05_ABSOLUTEMAX_TABLELOG + 1) * sizeof(U32));
weightTotal = 0;
for (n=0; n<oSize; n++) {
if (huffWeight[n] >= HUFv05_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
weightTotal += (1 << huffWeight[n]) >> 1;
ext/zstd/lib/legacy/zstd_v05.c view on Meta::CPAN
/* finish bitStreams one by one */
HUFv05_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
HUFv05_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
HUFv05_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
HUFv05_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BITv05_endOfDStream(&bitD1) & BITv05_endOfDStream(&bitD2) & BITv05_endOfDStream(&bitD3) & BITv05_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
size_t HUFv05_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUFv05_CREATE_STATIC_DTABLEX2(DTable, HUFv05_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
size_t errorCode;
ext/zstd/lib/legacy/zstd_v05.c view on Meta::CPAN
BITv05_DStream_t bitD;
errorCode = BITv05_initDStream(&bitD, istart, cSrcSize);
if (HUFv05_isError(errorCode)) return errorCode;
/* finish bitStreams one by one */
HUFv05_decodeStreamX4(ostart, &bitD, oend, dt, dtLog);
/* check */
if (!BITv05_endOfDStream(&bitD)) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
size_t HUFv05_decompress1X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUFv05_CREATE_STATIC_DTABLEX4(DTable, HUFv05_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
size_t hSize = HUFv05_readDTableX4 (DTable, cSrc, cSrcSize);
if (HUFv05_isError(hSize)) return hSize;
ext/zstd/lib/legacy/zstd_v05.c view on Meta::CPAN
/* finish bitStreams one by one */
HUFv05_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
HUFv05_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
HUFv05_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
HUFv05_decodeStreamX4(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BITv05_endOfDStream(&bitD1) & BITv05_endOfDStream(&bitD2) & BITv05_endOfDStream(&bitD3) & BITv05_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
size_t HUFv05_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUFv05_CREATE_STATIC_DTABLEX4(DTable, HUFv05_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
ext/zstd/lib/legacy/zstd_v05.c view on Meta::CPAN
if (ZSTDv05_isError(frameHeaderSize)) return frameHeaderSize;
if (srcSize < frameHeaderSize+ZSTDv05_blockHeaderSize) return ERROR(srcSize_wrong);
ip += frameHeaderSize; remainingSize -= frameHeaderSize;
frameHeaderSize = ZSTDv05_decodeFrameHeader_Part2(dctx, src, frameHeaderSize);
if (ZSTDv05_isError(frameHeaderSize)) return frameHeaderSize;
}
/* Loop on each block */
while (1)
{
size_t decodedSize=0;
size_t cBlockSize = ZSTDv05_getcBlockSize(ip, iend-ip, &blockProperties);
if (ZSTDv05_isError(cBlockSize)) return cBlockSize;
ip += ZSTDv05_blockHeaderSize;
remainingSize -= ZSTDv05_blockHeaderSize;
if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
switch(blockProperties.blockType)
{
case bt_compressed:
decodedSize = ZSTDv05_decompressBlock_internal(dctx, op, oend-op, ip, cBlockSize);
break;
case bt_raw :
decodedSize = ZSTDv05_copyRawBlock(op, oend-op, ip, cBlockSize);
break;
case bt_rle :
return ERROR(GENERIC); /* not yet supported */
break;
case bt_end :
/* end of frame */
if (remainingSize) return ERROR(srcSize_wrong);
break;
default:
return ERROR(GENERIC); /* impossible */
}
if (cBlockSize == 0) break; /* bt_end */
if (ZSTDv05_isError(decodedSize)) return decodedSize;
op += decodedSize;
ip += cBlockSize;
remainingSize -= cBlockSize;
}
return op-ostart;
}
size_t ZSTDv05_decompress_usingPreparedDCtx(ZSTDv05_DCtx* dctx, const ZSTDv05_DCtx* refDCtx,
void* dst, size_t maxDstSize,
ext/zstd/lib/legacy/zstd_v05.c view on Meta::CPAN
* Use ZBUFFv05_createDCtx() and ZBUFFv05_freeDCtx() to create/release resources.
* Use ZBUFFv05_decompressInit() to start a new decompression operation.
* ZBUFFv05_DCtx objects can be reused multiple times.
*
* Use ZBUFFv05_decompressContinue() repetitively to consume your input.
* *srcSizePtr and *maxDstSizePtr can be any size.
* The function will report how many bytes were read or written by modifying *srcSizePtr and *maxDstSizePtr.
* Note that it may not consume the entire input, in which case it's up to the caller to call again the function with remaining input.
* The content of dst will be overwritten (up to *maxDstSizePtr) at each function call, so save its content if it matters or change dst .
* return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to improve latency)
* or 0 when a frame is completely decoded
* or an error code, which can be tested using ZBUFFv05_isError().
*
* Hint : recommended buffer sizes (not compulsory)
* output : 128 KB block size is the internal unit, it ensures it's always possible to write a full block when it's decoded.
* input : just follow indications from ZBUFFv05_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
* **************************************************/
typedef enum { ZBUFFv05ds_init, ZBUFFv05ds_readHeader, ZBUFFv05ds_loadHeader, ZBUFFv05ds_decodeHeader,
ZBUFFv05ds_read, ZBUFFv05ds_load, ZBUFFv05ds_flush } ZBUFFv05_dStage;
/* *** Resource management *** */
#define ZSTDv05_frameHeaderSize_max 5 /* too magical, should come from reference */
struct ZBUFFv05_DCtx_s {
ext/zstd/lib/legacy/zstd_v05.c view on Meta::CPAN
case ZBUFFv05ds_read:
{
size_t neededInSize = ZSTDv05_nextSrcSizeToDecompress(zbc->zc);
if (neededInSize==0) { /* end of frame */
zbc->stage = ZBUFFv05ds_init;
notDone = 0;
break;
}
if ((size_t)(iend-ip) >= neededInSize) {
/* directly decode from src */
size_t decodedSize = ZSTDv05_decompressContinue(zbc->zc,
zbc->outBuff + zbc->outStart, zbc->outBuffSize - zbc->outStart,
ip, neededInSize);
if (ZSTDv05_isError(decodedSize)) return decodedSize;
ip += neededInSize;
if (!decodedSize) break; /* this was just a header */
zbc->outEnd = zbc->outStart + decodedSize;
zbc->stage = ZBUFFv05ds_flush;
break;
}
if (ip==iend) { notDone = 0; break; } /* no more input */
zbc->stage = ZBUFFv05ds_load;
}
/* fall-through */
case ZBUFFv05ds_load:
{
size_t neededInSize = ZSTDv05_nextSrcSizeToDecompress(zbc->zc);
size_t toLoad = neededInSize - zbc->inPos; /* should always be <= remaining space within inBuff */
size_t loadedSize;
if (toLoad > zbc->inBuffSize - zbc->inPos) return ERROR(corruption_detected); /* should never happen */
loadedSize = ZBUFFv05_limitCopy(zbc->inBuff + zbc->inPos, toLoad, ip, iend-ip);
ip += loadedSize;
zbc->inPos += loadedSize;
if (loadedSize < toLoad) { notDone = 0; break; } /* not enough input, wait for more */
{
size_t decodedSize = ZSTDv05_decompressContinue(zbc->zc,
zbc->outBuff + zbc->outStart, zbc->outBuffSize - zbc->outStart,
zbc->inBuff, neededInSize);
if (ZSTDv05_isError(decodedSize)) return decodedSize;
zbc->inPos = 0; /* input is consumed */
if (!decodedSize) { zbc->stage = ZBUFFv05ds_read; break; } /* this was just a header */
zbc->outEnd = zbc->outStart + decodedSize;
zbc->stage = ZBUFFv05ds_flush;
/* break; */ /* ZBUFFv05ds_flush follows */
}
}
/* fall-through */
case ZBUFFv05ds_flush:
{
size_t toFlushSize = zbc->outEnd - zbc->outStart;
size_t flushedSize = ZBUFFv05_limitCopy(op, oend-op, zbc->outBuff + zbc->outStart, toFlushSize);
op += flushedSize;
ext/zstd/lib/legacy/zstd_v05.h view on Meta::CPAN
* Use ZBUFFv05_decompressInit() to start a new decompression operation,
* or ZBUFFv05_decompressInitDictionary() if decompression requires a dictionary.
* Note that ZBUFFv05_DCtx objects can be reused multiple times.
*
* Use ZBUFFv05_decompressContinue() repetitively to consume your input.
* *srcSizePtr and *dstCapacityPtr can be any size.
* The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
* Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
* The content of @dst will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters or change @dst.
* @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to help latency)
* or 0 when a frame is completely decoded
* or an error code, which can be tested using ZBUFFv05_isError().
*
* Hint : recommended buffer sizes (not compulsory) : ZBUFFv05_recommendedDInSize() / ZBUFFv05_recommendedDOutSize()
* output : ZBUFFv05_recommendedDOutSize==128 KB block size is the internal unit, it ensures it's always possible to write a full block when decoded.
* input : ZBUFFv05_recommendedDInSize==128Kb+3; just follow indications from ZBUFFv05_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
* *******************************************************************************/
/* *************************************
* Tool functions
***************************************/
unsigned ZBUFFv05_isError(size_t errorCode);
const char* ZBUFFv05_getErrorName(size_t errorCode);
ext/zstd/lib/legacy/zstd_v06.c view on Meta::CPAN
Start decompression, with ZSTDv06_decompressBegin() or ZSTDv06_decompressBegin_usingDict().
Alternatively, you can copy a prepared context, using ZSTDv06_copyDCtx().
Then use ZSTDv06_nextSrcSizeToDecompress() and ZSTDv06_decompressContinue() alternatively.
ZSTDv06_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTDv06_decompressContinue().
ZSTDv06_decompressContinue() requires this exact amount of bytes, or it will fail.
ZSTDv06_decompressContinue() needs previous data blocks during decompression, up to (1 << windowlog).
They should preferably be located contiguously, prior to current block. Alternatively, a round buffer is also possible.
@result of ZSTDv06_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity)
It can be zero, which is not an error; it just means ZSTDv06_decompressContinue() has decoded some header.
A frame is fully decoded when ZSTDv06_nextSrcSizeToDecompress() returns zero.
Context can then be reset to start a new decompression.
*/
/* **************************************
* Block functions
****************************************/
/*! Block functions produce and decode raw zstd blocks, without frame metadata.
User will have to take in charge required information to regenerate data, such as compressed and content sizes.
ext/zstd/lib/legacy/zstd_v06.c view on Meta::CPAN
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
if (oSize >= hwSize) return ERROR(corruption_detected);
ip += 1;
{ U32 n;
for (n=0; n<oSize; n+=2) {
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
} } } }
else { /* header compressed with FSE (normal case) */
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
oSize = FSEv06_decompress(huffWeight, hwSize-1, ip+1, iSize); /* max (hwSize-1) values decoded, as last one is implied */
if (FSEv06_isError(oSize)) return oSize;
}
/* collect weight stats */
memset(rankStats, 0, (HUFv06_ABSOLUTEMAX_TABLELOG + 1) * sizeof(U32));
weightTotal = 0;
{ U32 n; for (n=0; n<oSize; n++) {
if (huffWeight[n] >= HUFv06_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
weightTotal += (1 << huffWeight[n]) >> 1;
ext/zstd/lib/legacy/zstd_v06.c view on Meta::CPAN
/* finish bitStreams one by one */
HUFv06_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
HUFv06_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
HUFv06_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
HUFv06_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BITv06_endOfDStream(&bitD1) & BITv06_endOfDStream(&bitD2) & BITv06_endOfDStream(&bitD3) & BITv06_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
size_t HUFv06_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUFv06_CREATE_STATIC_DTABLEX2(DTable, HUFv06_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
ext/zstd/lib/legacy/zstd_v06.c view on Meta::CPAN
BITv06_DStream_t bitD;
{ size_t const errorCode = BITv06_initDStream(&bitD, istart, cSrcSize);
if (HUFv06_isError(errorCode)) return errorCode; }
/* decode */
HUFv06_decodeStreamX4(ostart, &bitD, oend, dt, dtLog);
/* check */
if (!BITv06_endOfDStream(&bitD)) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
size_t HUFv06_decompress1X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUFv06_CREATE_STATIC_DTABLEX4(DTable, HUFv06_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
size_t const hSize = HUFv06_readDTableX4 (DTable, cSrc, cSrcSize);
if (HUFv06_isError(hSize)) return hSize;
ext/zstd/lib/legacy/zstd_v06.c view on Meta::CPAN
/* finish bitStreams one by one */
HUFv06_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
HUFv06_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
HUFv06_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
HUFv06_decodeStreamX4(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BITv06_endOfDStream(&bitD1) & BITv06_endOfDStream(&bitD2) & BITv06_endOfDStream(&bitD3) & BITv06_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
size_t HUFv06_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
{
HUFv06_CREATE_STATIC_DTABLEX4(DTable, HUFv06_MAX_TABLELOG);
const BYTE* ip = (const BYTE*) cSrc;
ext/zstd/lib/legacy/zstd_v06.c view on Meta::CPAN
/* Frame Header */
{ size_t const frameHeaderSize = ZSTDv06_frameHeaderSize(src, ZSTDv06_frameHeaderSize_min);
if (ZSTDv06_isError(frameHeaderSize)) return frameHeaderSize;
if (srcSize < frameHeaderSize+ZSTDv06_blockHeaderSize) return ERROR(srcSize_wrong);
if (ZSTDv06_decodeFrameHeader(dctx, src, frameHeaderSize)) return ERROR(corruption_detected);
ip += frameHeaderSize; remainingSize -= frameHeaderSize;
}
/* Loop on each block */
while (1) {
size_t decodedSize=0;
size_t const cBlockSize = ZSTDv06_getcBlockSize(ip, iend-ip, &blockProperties);
if (ZSTDv06_isError(cBlockSize)) return cBlockSize;
ip += ZSTDv06_blockHeaderSize;
remainingSize -= ZSTDv06_blockHeaderSize;
if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
switch(blockProperties.blockType)
{
case bt_compressed:
decodedSize = ZSTDv06_decompressBlock_internal(dctx, op, oend-op, ip, cBlockSize);
break;
case bt_raw :
decodedSize = ZSTDv06_copyRawBlock(op, oend-op, ip, cBlockSize);
break;
case bt_rle :
return ERROR(GENERIC); /* not yet supported */
break;
case bt_end :
/* end of frame */
if (remainingSize) return ERROR(srcSize_wrong);
break;
default:
return ERROR(GENERIC); /* impossible */
}
if (cBlockSize == 0) break; /* bt_end */
if (ZSTDv06_isError(decodedSize)) return decodedSize;
op += decodedSize;
ip += cBlockSize;
remainingSize -= cBlockSize;
}
return op-ostart;
}
size_t ZSTDv06_decompress_usingPreparedDCtx(ZSTDv06_DCtx* dctx, const ZSTDv06_DCtx* refDCtx,
void* dst, size_t dstCapacity,
ext/zstd/lib/legacy/zstd_v06.c view on Meta::CPAN
* Use ZBUFFv06_decompressInit() to start a new decompression operation,
* or ZBUFFv06_decompressInitDictionary() if decompression requires a dictionary.
* Note that ZBUFFv06_DCtx objects can be re-init multiple times.
*
* Use ZBUFFv06_decompressContinue() repetitively to consume your input.
* *srcSizePtr and *dstCapacityPtr can be any size.
* The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
* Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
* The content of @dst will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters, or change @dst.
* @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to help latency),
* or 0 when a frame is completely decoded,
* or an error code, which can be tested using ZBUFFv06_isError().
*
* Hint : recommended buffer sizes (not compulsory) : ZBUFFv06_recommendedDInSize() and ZBUFFv06_recommendedDOutSize()
* output : ZBUFFv06_recommendedDOutSize==128 KB block size is the internal unit, it ensures it's always possible to write a full block when decoded.
* input : ZBUFFv06_recommendedDInSize == 128KB + 3;
* just follow indications from ZBUFFv06_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
* *******************************************************************************/
typedef enum { ZBUFFds_init, ZBUFFds_loadHeader,
ZBUFFds_read, ZBUFFds_load, ZBUFFds_flush } ZBUFFv06_dStage;
/* *** Resource management *** */
struct ZBUFFv06_DCtx_s {
ZSTDv06_DCtx* zd;
ext/zstd/lib/legacy/zstd_v06.c view on Meta::CPAN
zbd->stage = ZBUFFds_read;
/* fall-through */
case ZBUFFds_read:
{ size_t const neededInSize = ZSTDv06_nextSrcSizeToDecompress(zbd->zd);
if (neededInSize==0) { /* end of frame */
zbd->stage = ZBUFFds_init;
notDone = 0;
break;
}
if ((size_t)(iend-ip) >= neededInSize) { /* decode directly from src */
size_t const decodedSize = ZSTDv06_decompressContinue(zbd->zd,
zbd->outBuff + zbd->outStart, zbd->outBuffSize - zbd->outStart,
ip, neededInSize);
if (ZSTDv06_isError(decodedSize)) return decodedSize;
ip += neededInSize;
if (!decodedSize) break; /* this was just a header */
zbd->outEnd = zbd->outStart + decodedSize;
zbd->stage = ZBUFFds_flush;
break;
}
if (ip==iend) { notDone = 0; break; } /* no more input */
zbd->stage = ZBUFFds_load;
}
/* fall-through */
case ZBUFFds_load:
{ size_t const neededInSize = ZSTDv06_nextSrcSizeToDecompress(zbd->zd);
size_t const toLoad = neededInSize - zbd->inPos; /* should always be <= remaining space within inBuff */
size_t loadedSize;
if (toLoad > zbd->inBuffSize - zbd->inPos) return ERROR(corruption_detected); /* should never happen */
loadedSize = ZBUFFv06_limitCopy(zbd->inBuff + zbd->inPos, toLoad, ip, iend-ip);
ip += loadedSize;
zbd->inPos += loadedSize;
if (loadedSize < toLoad) { notDone = 0; break; } /* not enough input, wait for more */
/* decode loaded input */
{ size_t const decodedSize = ZSTDv06_decompressContinue(zbd->zd,
zbd->outBuff + zbd->outStart, zbd->outBuffSize - zbd->outStart,
zbd->inBuff, neededInSize);
if (ZSTDv06_isError(decodedSize)) return decodedSize;
zbd->inPos = 0; /* input is consumed */
if (!decodedSize) { zbd->stage = ZBUFFds_read; break; } /* this was just a header */
zbd->outEnd = zbd->outStart + decodedSize;
zbd->stage = ZBUFFds_flush;
/* break; */ /* ZBUFFds_flush follows */
}
}
/* fall-through */
case ZBUFFds_flush:
{ size_t const toFlushSize = zbd->outEnd - zbd->outStart;
size_t const flushedSize = ZBUFFv06_limitCopy(op, oend-op, zbd->outBuff + zbd->outStart, toFlushSize);
op += flushedSize;
zbd->outStart += flushedSize;
ext/zstd/lib/legacy/zstd_v06.h view on Meta::CPAN
* Use ZBUFFv06_decompressInit() to start a new decompression operation,
* or ZBUFFv06_decompressInitDictionary() if decompression requires a dictionary.
* Note that ZBUFFv06_DCtx objects can be re-init multiple times.
*
* Use ZBUFFv06_decompressContinue() repetitively to consume your input.
* *srcSizePtr and *dstCapacityPtr can be any size.
* The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
* Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
* The content of `dst` will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters, or change `dst`.
* @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to help latency),
* or 0 when a frame is completely decoded,
* or an error code, which can be tested using ZBUFFv06_isError().
*
* Hint : recommended buffer sizes (not compulsory) : ZBUFFv06_recommendedDInSize() and ZBUFFv06_recommendedDOutSize()
* output : ZBUFFv06_recommendedDOutSize== 128 KB block size is the internal unit, it ensures it's always possible to write a full block when decoded.
* input : ZBUFFv06_recommendedDInSize == 128KB + 3;
* just follow indications from ZBUFFv06_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
* *******************************************************************************/
/* *************************************
* Tool functions
***************************************/
ZSTDLIBv06_API unsigned ZBUFFv06_isError(size_t errorCode);
ZSTDLIBv06_API const char* ZBUFFv06_getErrorName(size_t errorCode);
ext/zstd/lib/legacy/zstd_v07.c view on Meta::CPAN
errorCode, which can be tested using ZSTDv07_isError()
Start decompression, with ZSTDv07_decompressBegin() or ZSTDv07_decompressBegin_usingDict().
Alternatively, you can copy a prepared context, using ZSTDv07_copyDCtx().
Then use ZSTDv07_nextSrcSizeToDecompress() and ZSTDv07_decompressContinue() alternatively.
ZSTDv07_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTDv07_decompressContinue().
ZSTDv07_decompressContinue() requires this exact amount of bytes, or it will fail.
@result of ZSTDv07_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
It can be zero, which is not an error; it just means ZSTDv07_decompressContinue() has decoded some header.
ZSTDv07_decompressContinue() needs previous data blocks during decompression, up to `windowSize`.
They should preferably be located contiguously, prior to current block.
Alternatively, a round buffer of sufficient size is also possible. Sufficient size is determined by frame parameters.
ZSTDv07_decompressContinue() is very sensitive to contiguity,
if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place,
or that previous contiguous segment is large enough to properly handle maximum back-reference.
A frame is fully decoded when ZSTDv07_nextSrcSizeToDecompress() returns zero.
Context can then be reset to start a new decompression.
== Special case : skippable frames ==
Skippable frames allow the integration of user-defined data into a flow of concatenated frames.
Skippable frames will be ignored (skipped) by a decompressor. The format of skippable frame is following:
a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F
b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
c) Frame Content - any content (User Data) of length equal to Frame Size
ext/zstd/lib/legacy/zstd_v07.c view on Meta::CPAN
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
if (oSize >= hwSize) return ERROR(corruption_detected);
ip += 1;
{ U32 n;
for (n=0; n<oSize; n+=2) {
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
} } } }
else { /* header compressed with FSE (normal case) */
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
oSize = FSEv07_decompress(huffWeight, hwSize-1, ip+1, iSize); /* max (hwSize-1) values decoded, as last one is implied */
if (FSEv07_isError(oSize)) return oSize;
}
/* collect weight stats */
memset(rankStats, 0, (HUFv07_TABLELOG_ABSOLUTEMAX + 1) * sizeof(U32));
weightTotal = 0;
{ U32 n; for (n=0; n<oSize; n++) {
if (huffWeight[n] >= HUFv07_TABLELOG_ABSOLUTEMAX) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
weightTotal += (1 << huffWeight[n]) >> 1;
ext/zstd/lib/legacy/zstd_v07.c view on Meta::CPAN
/* finish bitStreams one by one */
HUFv07_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
HUFv07_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
HUFv07_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
HUFv07_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
/* check */
endSignal = BITv07_endOfDStream(&bitD1) & BITv07_endOfDStream(&bitD2) & BITv07_endOfDStream(&bitD3) & BITv07_endOfDStream(&bitD4);
if (!endSignal) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
}
size_t HUFv07_decompress4X2_usingDTable(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUFv07_DTable* DTable)
{
ext/zstd/lib/legacy/zstd_v07.c view on Meta::CPAN
BYTE* const oend = ostart + dstSize;
const void* const dtPtr = DTable+1; /* force compiler to not use strict-aliasing */
const HUFv07_DEltX4* const dt = (const HUFv07_DEltX4*)dtPtr;
DTableDesc const dtd = HUFv07_getDTableDesc(DTable);
HUFv07_decodeStreamX4(ostart, &bitD, oend, dt, dtd.tableLog);
}
/* check */
if (!BITv07_endOfDStream(&bitD)) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
size_t HUFv07_decompress1X4_usingDTable(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUFv07_DTable* DTable)
{
DTableDesc dtd = HUFv07_getDTableDesc(DTable);
if (dtd.tableType != 1) return ERROR(GENERIC);
ext/zstd/lib/legacy/zstd_v07.c view on Meta::CPAN
/* finish bitStreams one by one */
HUFv07_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
HUFv07_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
HUFv07_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
HUFv07_decodeStreamX4(op4, &bitD4, oend, dt, dtLog);
/* check */
{ U32 const endCheck = BITv07_endOfDStream(&bitD1) & BITv07_endOfDStream(&bitD2) & BITv07_endOfDStream(&bitD3) & BITv07_endOfDStream(&bitD4);
if (!endCheck) return ERROR(corruption_detected); }
/* decoded size */
return dstSize;
}
}
size_t HUFv07_decompress4X4_usingDTable(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUFv07_DTable* DTable)
{
ext/zstd/lib/legacy/zstd_v07.c view on Meta::CPAN
/* Frame Header */
{ size_t const frameHeaderSize = ZSTDv07_frameHeaderSize(src, ZSTDv07_frameHeaderSize_min);
if (ZSTDv07_isError(frameHeaderSize)) return frameHeaderSize;
if (srcSize < frameHeaderSize+ZSTDv07_blockHeaderSize) return ERROR(srcSize_wrong);
if (ZSTDv07_decodeFrameHeader(dctx, src, frameHeaderSize)) return ERROR(corruption_detected);
ip += frameHeaderSize; remainingSize -= frameHeaderSize;
}
/* Loop on each block */
while (1) {
size_t decodedSize;
blockProperties_t blockProperties;
size_t const cBlockSize = ZSTDv07_getcBlockSize(ip, iend-ip, &blockProperties);
if (ZSTDv07_isError(cBlockSize)) return cBlockSize;
ip += ZSTDv07_blockHeaderSize;
remainingSize -= ZSTDv07_blockHeaderSize;
if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
switch(blockProperties.blockType)
{
case bt_compressed:
decodedSize = ZSTDv07_decompressBlock_internal(dctx, op, oend-op, ip, cBlockSize);
break;
case bt_raw :
decodedSize = ZSTDv07_copyRawBlock(op, oend-op, ip, cBlockSize);
break;
case bt_rle :
decodedSize = ZSTDv07_generateNxBytes(op, oend-op, *ip, blockProperties.origSize);
break;
case bt_end :
/* end of frame */
if (remainingSize) return ERROR(srcSize_wrong);
decodedSize = 0;
break;
default:
return ERROR(GENERIC); /* impossible */
}
if (blockProperties.blockType == bt_end) break; /* bt_end */
if (ZSTDv07_isError(decodedSize)) return decodedSize;
if (dctx->fParams.checksumFlag) XXH64_update(&dctx->xxhState, op, decodedSize);
op += decodedSize;
ip += cBlockSize;
remainingSize -= cBlockSize;
}
return op-ostart;
}
/*! ZSTDv07_decompress_usingPreparedDCtx() :
* Same as ZSTDv07_decompress_usingDict, but using a reference context `preparedDCtx`, where dictionary has been loaded.
ext/zstd/lib/legacy/zstd_v07.c view on Meta::CPAN
* Use ZBUFFv07_decompressInit() to start a new decompression operation,
* or ZBUFFv07_decompressInitDictionary() if decompression requires a dictionary.
* Note that ZBUFFv07_DCtx objects can be re-init multiple times.
*
* Use ZBUFFv07_decompressContinue() repetitively to consume your input.
* *srcSizePtr and *dstCapacityPtr can be any size.
* The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
* Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
* The content of @dst will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters, or change @dst.
* @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to help latency),
* or 0 when a frame is completely decoded,
* or an error code, which can be tested using ZBUFFv07_isError().
*
* Hint : recommended buffer sizes (not compulsory) : ZBUFFv07_recommendedDInSize() and ZBUFFv07_recommendedDOutSize()
* output : ZBUFFv07_recommendedDOutSize==128 KB block size is the internal unit, it ensures it's always possible to write a full block when decoded.
* input : ZBUFFv07_recommendedDInSize == 128KB + 3;
* just follow indications from ZBUFFv07_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
* *******************************************************************************/
typedef enum { ZBUFFds_init, ZBUFFds_loadHeader,
ZBUFFds_read, ZBUFFds_load, ZBUFFds_flush } ZBUFFv07_dStage;
/* *** Resource management *** */
struct ZBUFFv07_DCtx_s {
ZSTDv07_DCtx* zd;
ext/zstd/lib/legacy/zstd_v07.c view on Meta::CPAN
/* fall-through */
case ZBUFFds_read:
{ size_t const neededInSize = ZSTDv07_nextSrcSizeToDecompress(zbd->zd);
if (neededInSize==0) { /* end of frame */
zbd->stage = ZBUFFds_init;
notDone = 0;
break;
}
if ((size_t)(iend-ip) >= neededInSize) { /* decode directly from src */
const int isSkipFrame = ZSTDv07_isSkipFrame(zbd->zd);
size_t const decodedSize = ZSTDv07_decompressContinue(zbd->zd,
zbd->outBuff + zbd->outStart, (isSkipFrame ? 0 : zbd->outBuffSize - zbd->outStart),
ip, neededInSize);
if (ZSTDv07_isError(decodedSize)) return decodedSize;
ip += neededInSize;
if (!decodedSize && !isSkipFrame) break; /* this was just a header */
zbd->outEnd = zbd->outStart + decodedSize;
zbd->stage = ZBUFFds_flush;
break;
}
if (ip==iend) { notDone = 0; break; } /* no more input */
zbd->stage = ZBUFFds_load;
}
/* fall-through */
case ZBUFFds_load:
{ size_t const neededInSize = ZSTDv07_nextSrcSizeToDecompress(zbd->zd);
size_t const toLoad = neededInSize - zbd->inPos; /* should always be <= remaining space within inBuff */
size_t loadedSize;
if (toLoad > zbd->inBuffSize - zbd->inPos) return ERROR(corruption_detected); /* should never happen */
loadedSize = ZBUFFv07_limitCopy(zbd->inBuff + zbd->inPos, toLoad, ip, iend-ip);
ip += loadedSize;
zbd->inPos += loadedSize;
if (loadedSize < toLoad) { notDone = 0; break; } /* not enough input, wait for more */
/* decode loaded input */
{ const int isSkipFrame = ZSTDv07_isSkipFrame(zbd->zd);
size_t const decodedSize = ZSTDv07_decompressContinue(zbd->zd,
zbd->outBuff + zbd->outStart, zbd->outBuffSize - zbd->outStart,
zbd->inBuff, neededInSize);
if (ZSTDv07_isError(decodedSize)) return decodedSize;
zbd->inPos = 0; /* input is consumed */
if (!decodedSize && !isSkipFrame) { zbd->stage = ZBUFFds_read; break; } /* this was just a header */
zbd->outEnd = zbd->outStart + decodedSize;
zbd->stage = ZBUFFds_flush;
/* break; */
/* pass-through */
}
}
/* fall-through */
case ZBUFFds_flush:
{ size_t const toFlushSize = zbd->outEnd - zbd->outStart;
size_t const flushedSize = ZBUFFv07_limitCopy(op, oend-op, zbd->outBuff + zbd->outStart, toFlushSize);
op += flushedSize;
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