/* Returns log2 of the size of main ring buffer area.
* Allocate at least lgwin + 1 bits for the ring buffer so that the newly
* added block fits there completely and we still get lgwin bits and at least
* read_block_size_bits + 1 bits because the copy tail length needs to be
* smaller than ring-buffer size. */
private static unsafe int ComputeRbBits(BrotliEncoderParams *params_)
{
return(1 + Math.Max(params_->lgwin, params_->lgblock));
}
/* When searching for backward references and have not seen matches for a long
* time, we can skip some match lookups. Unsuccessful match lookups are very
* expensive and this kind of a heuristic speeds up compression quite a lot.
* At first 8 byte strides are taken and every second byte is put to hasher.
* After 4x more literals stride by 16 bytes, every put 4-th byte to hasher.
* Applied only to qualities 2 to 9. */
private static unsafe size_t LiteralSpreeLengthForSparseSearch(
BrotliEncoderParams *params_)
{
return(params_->quality < 9 ? 64 : 512);
}
/* Number of best candidates to evaluate to expand Zopfli chain. */
private static unsafe size_t MaxZopfliCandidates(
BrotliEncoderParams *params_)
{
return(params_->quality <= 10 ? 1 : 5);
}
private static unsafe size_t MaxZopfliLen(BrotliEncoderParams *params_)
{
return(params_->quality <= 10 ?
MAX_ZOPFLI_LEN_QUALITY_10 :
MAX_ZOPFLI_LEN_QUALITY_11);
}
