Digest-xxHash

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ext/xxHash/README.md  view on Meta::CPAN

- `XXH_SIZE_OPT`: `0`: default, optimize for speed
                  `1`: default for `-Os` and `-Oz`: disables some speed hacks for size optimization
                  `2`: makes code as small as possible, performance may cry

#### Build modifiers specific for XXH3
- `XXH_VECTOR` : manually select a vector instruction set (default: auto-selected at compilation time). Available instruction sets are `XXH_SCALAR`, `XXH_SSE2`, `XXH_AVX2`, `XXH_AVX512`, `XXH_NEON` and `XXH_VSX`. Compiler may require additional flags...
- `XXH_PREFETCH_DIST` : select prefetching distance. For close-to-metal adaptation to specific hardware platforms. XXH3 only.
- `XXH_NO_PREFETCH` : disable prefetching. Some platforms or situations may perform better without prefetching. XXH3 only.

#### Build modifiers for `xxhsum` CLI
- `XXH_1ST_SPEED_TARGET` : select an initial speed target, expressed in MB/s, for the first speed test in benchmark mode. Benchmark will adjust the target at subsequent iterations, but the first test is made "blindly" by targeting this speed. Current...

#### Makefile variables
When compiling the Command Line Interface `xxhsum` using `make`, the following environment variables can also be set :
- `DISPATCH=1` : use `xxh_x86dispatch.c`, select at runtime between `scalar`, `sse2`, `avx2` or `avx512` instruction set. This option is only valid for `x86`/`x64` systems. It is enabled by default when target `x86`/`x64` is detected. It can be force...
- `LIBXXH_DISPATCH=1` : same idea, implemented a runtime vector extension detector, but within `libxxhash`. This parameter is disabled by default. When enabled (only valid for `x86`/`x64` systems), new symbols published in `xxh_x86dispatch.h` become ...
- `NODE_JS=1` : When compiling `xxhsum` for Node.js with Emscripten, this links the `NODERAWFS` library for unrestricted filesystem access and patches `isatty` to make the command line utility correctly detect the terminal. This does make the binary ...

### Building xxHash - Using vcpkg

You can download and install xxHash using the [vcpkg](https://github.com/Microsoft/vcpkg) dependency manager:

ext/xxHash/cli/xsum_bench.c  view on Meta::CPAN

             *
             * For example, on a Core 2 Duo (without any sort of Turbo Boost),
             * the imprecise timer caused peculiar results like so:
             *
             *    XXH3_64b                   4800.0 MB/s // conveniently even
             *    XXH3_64b unaligned         4800.0 MB/s
             *    XXH3_64b seeded            9600.0 MB/s // magical 2x speedup?!
             *    XXH3_64b seeded unaligned  4800.0 MB/s
             *
             * If we sense a suspiciously low number of ticks, we increase the
             * iterations until we can get something meaningful.
             */
            if (nbTicks < TIMELOOP_MIN) {
                /* Not enough time spent in benchmarking, risk of rounding bias */
                if (nbTicks == 0) { /* faster than resolution timer */
                    nbh_perIteration *= 100;
                } else {
                    /*
                     * update nbh_perIteration so that the next round lasts
                     * approximately 1 second.
                     */

ext/xxHash/cli/xsum_bench.h  view on Meta::CPAN

 * You can contact the author at:
 *   - xxHash homepage: https://www.xxhash.com
 *   - xxHash source repository: https://github.com/Cyan4973/xxHash
 */

#ifndef XSUM_BENCH_H
#define XSUM_BENCH_H

#include <stddef.h>  /* size_t */

#define NBLOOPS_DEFAULT    3    /* Default number of benchmark iterations */

extern int const g_nbTestFunctions;
extern char g_testIDs[];  /* size : g_nbTestFunctions */
extern const char k_testIDs_default[];
extern int g_nbIterations;

int XSUM_benchInternal(size_t keySize);
int XSUM_benchFiles(const char* fileNamesTable[], int nbFiles);

ext/xxHash/cli/xxhsum.1  view on Meta::CPAN

.TP
\fB\-b#\fR
Specify ID of variant to be tested\. Multiple variants can be selected, separated by a \',\' comma\.
.
.TP
\fB\-B\fR\fIBLOCKSIZE\fR
Only useful for benchmark mode (\fB\-b\fR)\. See \fIEXAMPLES\fR for details\. \fIBLOCKSIZE\fR specifies benchmark mode\'s test data block size in bytes\. Default value is 102400
.
.TP
\fB\-i\fR\fIITERATIONS\fR
Only useful for benchmark mode (\fB\-b\fR)\. See \fIEXAMPLES\fR for details\. \fIITERATIONS\fR specifies number of iterations in benchmark\. Single iteration lasts approximately 1000 milliseconds\. Default value is 3
.
.SH "EXIT STATUS"
\fBxxhsum\fR exit \fB0\fR on success, \fB1\fR if at least one file couldn\'t be read or doesn\'t have the same checksum as the \fB\-c\fR option\.
.
.SH "EXAMPLES"
Output xxHash (64bit) checksum values of specific files to standard output
.
.IP "" 4
.
.nf

ext/xxHash/cli/xxhsum.1.md  view on Meta::CPAN

  Specify ID of variant to be tested.
  Multiple variants can be selected, separated by a ',' comma.

* `-B`*BLOCKSIZE*:
  Only useful for benchmark mode (`-b`). See *EXAMPLES* for details.
  <BLOCKSIZE> specifies benchmark mode's test data block size in bytes.
  Default value is 102400

* `-i`*ITERATIONS*:
  Only useful for benchmark mode (`-b`). See *EXAMPLES* for details.
  <ITERATIONS> specifies number of iterations in benchmark. Single iteration
  lasts approximately 1000 milliseconds. Default value is 3

EXIT STATUS
-----------

`xxhsum` exit `0` on success, `1` if at least one file couldn't be read or
doesn't have the same checksum as the `-c` option.

EXAMPLES
--------