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brotli/c/include/brotli/encode.h  view on Meta::CPAN

  BROTLI_OPERATION_FINISH = 2,
  /**
   * Emit metadata block to stream.
   *
   * Metadata is opaque to Brotli: neither encoder, nor decoder processes this
   * data or relies on it. It may be used to pass some extra information from
   * encoder client to decoder client without interfering with main data stream.
   *
   * @note Encoder may emit empty metadata blocks internally, to pad encoded
   *       stream to byte boundary.
   *
   * @warning Until emitting metadata is complete client @b SHOULD @b NOT swap,
   *          reduce or extend input stream.
   *
   * @warning The whole content of input buffer is considered to be the content
   *          of metadata block. Do @b NOT @e append metadata to input stream,
   *          before it is depleted with other operations.
   *
   * Stream is soft-flushed before metadata block is emitted. Metadata block
   * @b MUST be no longer than than 16MiB.
   */
  BROTLI_OPERATION_EMIT_METADATA = 3
} BrotliEncoderOperation;

/** Options to be used with ::BrotliEncoderSetParameter. */
typedef enum BrotliEncoderParameter {
  /**
   * Tune encoder for specific input.
   *
   * ::BrotliEncoderMode enumerates all available values.
   */
  BROTLI_PARAM_MODE = 0,
  /**
   * The main compression speed-density lever.
   *
   * The higher the quality, the slower the compression. Range is
   * from ::BROTLI_MIN_QUALITY to ::BROTLI_MAX_QUALITY.
   */
  BROTLI_PARAM_QUALITY = 1,
  /**
   * Recommended sliding LZ77 window size.
   *
   * Encoder may reduce this value, e.g. if input is much smaller than
   * window size.
   *
   * Window size is `(1 << value) - 16`.
   *
   * Range is from ::BROTLI_MIN_WINDOW_BITS to ::BROTLI_MAX_WINDOW_BITS.
   */
  BROTLI_PARAM_LGWIN = 2,
  /**
   * Recommended input block size.
   *
   * Encoder may reduce this value, e.g. if input is much smaller than input
   * block size.
   *
   * Range is from ::BROTLI_MIN_INPUT_BLOCK_BITS to
   * ::BROTLI_MAX_INPUT_BLOCK_BITS.
   *
   * @note Bigger input block size allows better compression, but consumes more
   *       memory. \n The rough formula of memory used for temporary input
   *       storage is `3 << lgBlock`.
   */
  BROTLI_PARAM_LGBLOCK = 3,
  /**
   * Flag that affects usage of "literal context modeling" format feature.
   *
   * This flag is a "decoding-speed vs compression ratio" trade-off.
   */
  BROTLI_PARAM_DISABLE_LITERAL_CONTEXT_MODELING = 4,
  /**
   * Estimated total input size for all ::BrotliEncoderCompressStream calls.
   *
   * The default value is 0, which means that the total input size is unknown.
   */
  BROTLI_PARAM_SIZE_HINT = 5,
  /**
   * Flag that determines if "Large Window Brotli" is used.
   */
  BROTLI_PARAM_LARGE_WINDOW = 6,
  /**
   * Recommended number of postfix bits (NPOSTFIX).
   *
   * Encoder may change this value.
   *
   * Range is from 0 to ::BROTLI_MAX_NPOSTFIX.
   */
  BROTLI_PARAM_NPOSTFIX = 7,
  /**
   * Recommended number of direct distance codes (NDIRECT).
   *
   * Encoder may change this value.
   *
   * Range is from 0 to (15 << NPOSTFIX) in steps of (1 << NPOSTFIX).
   */
  BROTLI_PARAM_NDIRECT = 8
} BrotliEncoderParameter;

/**
 * Opaque structure that holds encoder state.
 *
 * Allocated and initialized with ::BrotliEncoderCreateInstance.
 * Cleaned up and deallocated with ::BrotliEncoderDestroyInstance.
 */
typedef struct BrotliEncoderStateStruct BrotliEncoderState;

/**
 * Sets the specified parameter to the given encoder instance.
 *
 * @param state encoder instance
 * @param param parameter to set
 * @param value new parameter value
 * @returns ::BROTLI_FALSE if parameter is unrecognized, or value is invalid
 * @returns ::BROTLI_FALSE if value of parameter can not be changed at current
 *          encoder state (e.g. when encoding is started, window size might be
 *          already encoded and therefore it is impossible to change it)
 * @returns ::BROTLI_TRUE if value is accepted
 * @warning invalid values might be accepted in case they would not break
 *          encoding process.
 */
BROTLI_ENC_API BROTLI_BOOL BrotliEncoderSetParameter(