diff options
Diffstat (limited to 'c/enc/command.h')
| -rw-r--r-- | c/enc/command.h | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/c/enc/command.h b/c/enc/command.h index 0526815..6075dfe 100644 --- a/c/enc/command.h +++ b/c/enc/command.h @@ -13,6 +13,7 @@ #include "../common/platform.h" #include <brotli/types.h> #include "./fast_log.h" +#include "./params.h" #include "./prefix.h" #if defined(__cplusplus) || defined(c_plusplus) @@ -116,7 +117,8 @@ typedef struct Command { } Command; /* distance_code is e.g. 0 for same-as-last short code, or 16 for offset 1. */ -static BROTLI_INLINE void InitCommand(Command* self, size_t insertlen, +static BROTLI_INLINE void InitCommand(Command* self, + const BrotliDistanceParams* dist, size_t insertlen, size_t copylen, int copylen_code_delta, size_t distance_code) { /* Don't rely on signed int representation, use honest casts. */ uint32_t delta = (uint8_t)((int8_t)copylen_code_delta); @@ -126,7 +128,8 @@ static BROTLI_INLINE void InitCommand(Command* self, size_t insertlen, npostfix and ndirect were 0, they are only recomputed later after the clustering if needed. */ PrefixEncodeCopyDistance( - distance_code, 0, 0, &self->dist_prefix_, &self->dist_extra_); + distance_code, dist->num_direct_distance_codes, + dist->distance_postfix_bits, &self->dist_prefix_, &self->dist_extra_); GetLengthCode( insertlen, (size_t)((int)copylen + copylen_code_delta), TO_BROTLI_BOOL((self->dist_prefix_ & 0x3FF) == 0), &self->cmd_prefix_); @@ -140,21 +143,24 @@ static BROTLI_INLINE void InitInsertCommand(Command* self, size_t insertlen) { GetLengthCode(insertlen, 4, BROTLI_FALSE, &self->cmd_prefix_); } -static BROTLI_INLINE uint32_t CommandRestoreDistanceCode(const Command* self) { - if ((self->dist_prefix_ & 0x3FF) < BROTLI_NUM_DISTANCE_SHORT_CODES) { +static BROTLI_INLINE uint32_t CommandRestoreDistanceCode( + const Command* self, const BrotliDistanceParams* dist) { + if ((self->dist_prefix_ & 0x3FF) < + BROTLI_NUM_DISTANCE_SHORT_CODES + dist->num_direct_distance_codes) { return self->dist_prefix_ & 0x3FF; } else { + uint32_t dcode = self->dist_prefix_ & 0x3FF; uint32_t nbits = self->dist_prefix_ >> 10; uint32_t extra = self->dist_extra_; - /* It is assumed that the distance was first encoded with NPOSTFIX = 0 and - NDIRECT = 0, so the code itself is of this form: - BROTLI_NUM_DISTANCE_SHORT_CODES + 2 * (nbits - 1) + prefix_bit - Therefore, the following expression results in (2 + prefix_bit). */ - uint32_t prefix = (self->dist_prefix_ & 0x3FF) + 4u - - BROTLI_NUM_DISTANCE_SHORT_CODES - 2u * nbits; - /* Subtract 4 for offset (Chapter 4.) and - increase by BROTLI_NUM_DISTANCE_SHORT_CODES - 1 */ - return (prefix << nbits) + extra + BROTLI_NUM_DISTANCE_SHORT_CODES - 4u; + uint32_t postfix_mask = (1U << dist->distance_postfix_bits) - 1U; + uint32_t hcode = (dcode - dist->num_direct_distance_codes - + BROTLI_NUM_DISTANCE_SHORT_CODES) >> + dist->distance_postfix_bits; + uint32_t lcode = (dcode - dist->num_direct_distance_codes - + BROTLI_NUM_DISTANCE_SHORT_CODES) & postfix_mask; + uint32_t offset = ((2U + (hcode & 1U)) << nbits) - 4U; + return ((offset + extra) << dist->distance_postfix_bits) + lcode + + dist->num_direct_distance_codes + BROTLI_NUM_DISTANCE_SHORT_CODES; } } |