diff options
Diffstat (limited to 'deps/node/deps/brotli/c/enc/compress_fragment.c')
| -rw-r--r-- | deps/node/deps/brotli/c/enc/compress_fragment.c | 790 |
1 files changed, 0 insertions, 790 deletions
diff --git a/deps/node/deps/brotli/c/enc/compress_fragment.c b/deps/node/deps/brotli/c/enc/compress_fragment.c deleted file mode 100644 index 9e50b209..00000000 --- a/deps/node/deps/brotli/c/enc/compress_fragment.c +++ /dev/null @@ -1,790 +0,0 @@ -/* Copyright 2015 Google Inc. All Rights Reserved. - - Distributed under MIT license. - See file LICENSE for detail or copy at https://opensource.org/licenses/MIT -*/ - -/* Function for fast encoding of an input fragment, independently from the input - history. This function uses one-pass processing: when we find a backward - match, we immediately emit the corresponding command and literal codes to - the bit stream. - - Adapted from the CompressFragment() function in - https://github.com/google/snappy/blob/master/snappy.cc */ - -#include "./compress_fragment.h" - -#include <string.h> /* memcmp, memcpy, memset */ - -#include "../common/constants.h" -#include "../common/platform.h" -#include <brotli/types.h> -#include "./brotli_bit_stream.h" -#include "./entropy_encode.h" -#include "./fast_log.h" -#include "./find_match_length.h" -#include "./memory.h" -#include "./write_bits.h" - -#if defined(__cplusplus) || defined(c_plusplus) -extern "C" { -#endif - -#define MAX_DISTANCE (long)BROTLI_MAX_BACKWARD_LIMIT(18) - -/* kHashMul32 multiplier has these properties: - * The multiplier must be odd. Otherwise we may lose the highest bit. - * No long streaks of ones or zeros. - * There is no effort to ensure that it is a prime, the oddity is enough - for this use. - * The number has been tuned heuristically against compression benchmarks. */ -static const uint32_t kHashMul32 = 0x1E35A7BD; - -static BROTLI_INLINE uint32_t Hash(const uint8_t* p, size_t shift) { - const uint64_t h = (BROTLI_UNALIGNED_LOAD64LE(p) << 24) * kHashMul32; - return (uint32_t)(h >> shift); -} - -static BROTLI_INLINE uint32_t HashBytesAtOffset( - uint64_t v, int offset, size_t shift) { - BROTLI_DCHECK(offset >= 0); - BROTLI_DCHECK(offset <= 3); - { - const uint64_t h = ((v >> (8 * offset)) << 24) * kHashMul32; - return (uint32_t)(h >> shift); - } -} - -static BROTLI_INLINE BROTLI_BOOL IsMatch(const uint8_t* p1, const uint8_t* p2) { - return TO_BROTLI_BOOL( - BrotliUnalignedRead32(p1) == BrotliUnalignedRead32(p2) && - p1[4] == p2[4]); -} - -/* Builds a literal prefix code into "depths" and "bits" based on the statistics - of the "input" string and stores it into the bit stream. - Note that the prefix code here is built from the pre-LZ77 input, therefore - we can only approximate the statistics of the actual literal stream. - Moreover, for long inputs we build a histogram from a sample of the input - and thus have to assign a non-zero depth for each literal. - Returns estimated compression ratio millibytes/char for encoding given input - with generated code. */ -static size_t BuildAndStoreLiteralPrefixCode(MemoryManager* m, - const uint8_t* input, - const size_t input_size, - uint8_t depths[256], - uint16_t bits[256], - size_t* storage_ix, - uint8_t* storage) { - uint32_t histogram[256] = { 0 }; - size_t histogram_total; - size_t i; - if (input_size < (1 << 15)) { - for (i = 0; i < input_size; ++i) { - ++histogram[input[i]]; - } - histogram_total = input_size; - for (i = 0; i < 256; ++i) { - /* We weigh the first 11 samples with weight 3 to account for the - balancing effect of the LZ77 phase on the histogram. */ - const uint32_t adjust = 2 * BROTLI_MIN(uint32_t, histogram[i], 11u); - histogram[i] += adjust; - histogram_total += adjust; - } - } else { - static const size_t kSampleRate = 29; - for (i = 0; i < input_size; i += kSampleRate) { - ++histogram[input[i]]; - } - histogram_total = (input_size + kSampleRate - 1) / kSampleRate; - for (i = 0; i < 256; ++i) { - /* We add 1 to each population count to avoid 0 bit depths (since this is - only a sample and we don't know if the symbol appears or not), and we - weigh the first 11 samples with weight 3 to account for the balancing - effect of the LZ77 phase on the histogram (more frequent symbols are - more likely to be in backward references instead as literals). */ - const uint32_t adjust = 1 + 2 * BROTLI_MIN(uint32_t, histogram[i], 11u); - histogram[i] += adjust; - histogram_total += adjust; - } - } - BrotliBuildAndStoreHuffmanTreeFast(m, histogram, histogram_total, - /* max_bits = */ 8, - depths, bits, storage_ix, storage); - if (BROTLI_IS_OOM(m)) return 0; - { - size_t literal_ratio = 0; - for (i = 0; i < 256; ++i) { - if (histogram[i]) literal_ratio += histogram[i] * depths[i]; - } - /* Estimated encoding ratio, millibytes per symbol. */ - return (literal_ratio * 125) / histogram_total; - } -} - -/* Builds a command and distance prefix code (each 64 symbols) into "depth" and - "bits" based on "histogram" and stores it into the bit stream. */ -static void BuildAndStoreCommandPrefixCode(const uint32_t histogram[128], - uint8_t depth[128], uint16_t bits[128], size_t* storage_ix, - uint8_t* storage) { - /* Tree size for building a tree over 64 symbols is 2 * 64 + 1. */ - HuffmanTree tree[129]; - uint8_t cmd_depth[BROTLI_NUM_COMMAND_SYMBOLS] = { 0 }; - uint16_t cmd_bits[64]; - - BrotliCreateHuffmanTree(histogram, 64, 15, tree, depth); - BrotliCreateHuffmanTree(&histogram[64], 64, 14, tree, &depth[64]); - /* We have to jump through a few hoops here in order to compute - the command bits because the symbols are in a different order than in - the full alphabet. This looks complicated, but having the symbols - in this order in the command bits saves a few branches in the Emit* - functions. */ - memcpy(cmd_depth, depth, 24); - memcpy(cmd_depth + 24, depth + 40, 8); - memcpy(cmd_depth + 32, depth + 24, 8); - memcpy(cmd_depth + 40, depth + 48, 8); - memcpy(cmd_depth + 48, depth + 32, 8); - memcpy(cmd_depth + 56, depth + 56, 8); - BrotliConvertBitDepthsToSymbols(cmd_depth, 64, cmd_bits); - memcpy(bits, cmd_bits, 48); - memcpy(bits + 24, cmd_bits + 32, 16); - memcpy(bits + 32, cmd_bits + 48, 16); - memcpy(bits + 40, cmd_bits + 24, 16); - memcpy(bits + 48, cmd_bits + 40, 16); - memcpy(bits + 56, cmd_bits + 56, 16); - BrotliConvertBitDepthsToSymbols(&depth[64], 64, &bits[64]); - { - /* Create the bit length array for the full command alphabet. */ - size_t i; - memset(cmd_depth, 0, 64); /* only 64 first values were used */ - memcpy(cmd_depth, depth, 8); - memcpy(cmd_depth + 64, depth + 8, 8); - memcpy(cmd_depth + 128, depth + 16, 8); - memcpy(cmd_depth + 192, depth + 24, 8); - memcpy(cmd_depth + 384, depth + 32, 8); - for (i = 0; i < 8; ++i) { - cmd_depth[128 + 8 * i] = depth[40 + i]; - cmd_depth[256 + 8 * i] = depth[48 + i]; - cmd_depth[448 + 8 * i] = depth[56 + i]; - } - BrotliStoreHuffmanTree( - cmd_depth, BROTLI_NUM_COMMAND_SYMBOLS, tree, storage_ix, storage); - } - BrotliStoreHuffmanTree(&depth[64], 64, tree, storage_ix, storage); -} - -/* REQUIRES: insertlen < 6210 */ -static BROTLI_INLINE void EmitInsertLen(size_t insertlen, - const uint8_t depth[128], - const uint16_t bits[128], - uint32_t histo[128], - size_t* storage_ix, - uint8_t* storage) { - if (insertlen < 6) { - const size_t code = insertlen + 40; - BrotliWriteBits(depth[code], bits[code], storage_ix, storage); - ++histo[code]; - } else if (insertlen < 130) { - const size_t tail = insertlen - 2; - const uint32_t nbits = Log2FloorNonZero(tail) - 1u; - const size_t prefix = tail >> nbits; - const size_t inscode = (nbits << 1) + prefix + 42; - BrotliWriteBits(depth[inscode], bits[inscode], storage_ix, storage); - BrotliWriteBits(nbits, tail - (prefix << nbits), storage_ix, storage); - ++histo[inscode]; - } else if (insertlen < 2114) { - const size_t tail = insertlen - 66; - const uint32_t nbits = Log2FloorNonZero(tail); - const size_t code = nbits + 50; - BrotliWriteBits(depth[code], bits[code], storage_ix, storage); - BrotliWriteBits(nbits, tail - ((size_t)1 << nbits), storage_ix, storage); - ++histo[code]; - } else { - BrotliWriteBits(depth[61], bits[61], storage_ix, storage); - BrotliWriteBits(12, insertlen - 2114, storage_ix, storage); - ++histo[61]; - } -} - -static BROTLI_INLINE void EmitLongInsertLen(size_t insertlen, - const uint8_t depth[128], - const uint16_t bits[128], - uint32_t histo[128], - size_t* storage_ix, - uint8_t* storage) { - if (insertlen < 22594) { - BrotliWriteBits(depth[62], bits[62], storage_ix, storage); - BrotliWriteBits(14, insertlen - 6210, storage_ix, storage); - ++histo[62]; - } else { - BrotliWriteBits(depth[63], bits[63], storage_ix, storage); - BrotliWriteBits(24, insertlen - 22594, storage_ix, storage); - ++histo[63]; - } -} - -static BROTLI_INLINE void EmitCopyLen(size_t copylen, - const uint8_t depth[128], - const uint16_t bits[128], - uint32_t histo[128], - size_t* storage_ix, - uint8_t* storage) { - if (copylen < 10) { - BrotliWriteBits( - depth[copylen + 14], bits[copylen + 14], storage_ix, storage); - ++histo[copylen + 14]; - } else if (copylen < 134) { - const size_t tail = copylen - 6; - const uint32_t nbits = Log2FloorNonZero(tail) - 1u; - const size_t prefix = tail >> nbits; - const size_t code = (nbits << 1) + prefix + 20; - BrotliWriteBits(depth[code], bits[code], storage_ix, storage); - BrotliWriteBits(nbits, tail - (prefix << nbits), storage_ix, storage); - ++histo[code]; - } else if (copylen < 2118) { - const size_t tail = copylen - 70; - const uint32_t nbits = Log2FloorNonZero(tail); - const size_t code = nbits + 28; - BrotliWriteBits(depth[code], bits[code], storage_ix, storage); - BrotliWriteBits(nbits, tail - ((size_t)1 << nbits), storage_ix, storage); - ++histo[code]; - } else { - BrotliWriteBits(depth[39], bits[39], storage_ix, storage); - BrotliWriteBits(24, copylen - 2118, storage_ix, storage); - ++histo[39]; - } -} - -static BROTLI_INLINE void EmitCopyLenLastDistance(size_t copylen, - const uint8_t depth[128], - const uint16_t bits[128], - uint32_t histo[128], - size_t* storage_ix, - uint8_t* storage) { - if (copylen < 12) { - BrotliWriteBits(depth[copylen - 4], bits[copylen - 4], storage_ix, storage); - ++histo[copylen - 4]; - } else if (copylen < 72) { - const size_t tail = copylen - 8; - const uint32_t nbits = Log2FloorNonZero(tail) - 1; - const size_t prefix = tail >> nbits; - const size_t code = (nbits << 1) + prefix + 4; - BrotliWriteBits(depth[code], bits[code], storage_ix, storage); - BrotliWriteBits(nbits, tail - (prefix << nbits), storage_ix, storage); - ++histo[code]; - } else if (copylen < 136) { - const size_t tail = copylen - 8; - const size_t code = (tail >> 5) + 30; - BrotliWriteBits(depth[code], bits[code], storage_ix, storage); - BrotliWriteBits(5, tail & 31, storage_ix, storage); - BrotliWriteBits(depth[64], bits[64], storage_ix, storage); - ++histo[code]; - ++histo[64]; - } else if (copylen < 2120) { - const size_t tail = copylen - 72; - const uint32_t nbits = Log2FloorNonZero(tail); - const size_t code = nbits + 28; - BrotliWriteBits(depth[code], bits[code], storage_ix, storage); - BrotliWriteBits(nbits, tail - ((size_t)1 << nbits), storage_ix, storage); - BrotliWriteBits(depth[64], bits[64], storage_ix, storage); - ++histo[code]; - ++histo[64]; - } else { - BrotliWriteBits(depth[39], bits[39], storage_ix, storage); - BrotliWriteBits(24, copylen - 2120, storage_ix, storage); - BrotliWriteBits(depth[64], bits[64], storage_ix, storage); - ++histo[39]; - ++histo[64]; - } -} - -static BROTLI_INLINE void EmitDistance(size_t distance, - const uint8_t depth[128], - const uint16_t bits[128], - uint32_t histo[128], - size_t* storage_ix, uint8_t* storage) { - const size_t d = distance + 3; - const uint32_t nbits = Log2FloorNonZero(d) - 1u; - const size_t prefix = (d >> nbits) & 1; - const size_t offset = (2 + prefix) << nbits; - const size_t distcode = 2 * (nbits - 1) + prefix + 80; - BrotliWriteBits(depth[distcode], bits[distcode], storage_ix, storage); - BrotliWriteBits(nbits, d - offset, storage_ix, storage); - ++histo[distcode]; -} - -static BROTLI_INLINE void EmitLiterals(const uint8_t* input, const size_t len, - const uint8_t depth[256], - const uint16_t bits[256], - size_t* storage_ix, uint8_t* storage) { - size_t j; - for (j = 0; j < len; j++) { - const uint8_t lit = input[j]; - BrotliWriteBits(depth[lit], bits[lit], storage_ix, storage); - } -} - -/* REQUIRES: len <= 1 << 24. */ -static void BrotliStoreMetaBlockHeader( - size_t len, BROTLI_BOOL is_uncompressed, size_t* storage_ix, - uint8_t* storage) { - size_t nibbles = 6; - /* ISLAST */ - BrotliWriteBits(1, 0, storage_ix, storage); - if (len <= (1U << 16)) { - nibbles = 4; - } else if (len <= (1U << 20)) { - nibbles = 5; - } - BrotliWriteBits(2, nibbles - 4, storage_ix, storage); - BrotliWriteBits(nibbles * 4, len - 1, storage_ix, storage); - /* ISUNCOMPRESSED */ - BrotliWriteBits(1, (uint64_t)is_uncompressed, storage_ix, storage); -} - -static void UpdateBits(size_t n_bits, uint32_t bits, size_t pos, - uint8_t* array) { - while (n_bits > 0) { - size_t byte_pos = pos >> 3; - size_t n_unchanged_bits = pos & 7; - size_t n_changed_bits = BROTLI_MIN(size_t, n_bits, 8 - n_unchanged_bits); - size_t total_bits = n_unchanged_bits + n_changed_bits; - uint32_t mask = - (~((1u << total_bits) - 1u)) | ((1u << n_unchanged_bits) - 1u); - uint32_t unchanged_bits = array[byte_pos] & mask; - uint32_t changed_bits = bits & ((1u << n_changed_bits) - 1u); - array[byte_pos] = - (uint8_t)((changed_bits << n_unchanged_bits) | unchanged_bits); - n_bits -= n_changed_bits; - bits >>= n_changed_bits; - pos += n_changed_bits; - } -} - -static void RewindBitPosition(const size_t new_storage_ix, - size_t* storage_ix, uint8_t* storage) { - const size_t bitpos = new_storage_ix & 7; - const size_t mask = (1u << bitpos) - 1; - storage[new_storage_ix >> 3] &= (uint8_t)mask; - *storage_ix = new_storage_ix; -} - -static BROTLI_BOOL ShouldMergeBlock( - const uint8_t* data, size_t len, const uint8_t* depths) { - size_t histo[256] = { 0 }; - static const size_t kSampleRate = 43; - size_t i; - for (i = 0; i < len; i += kSampleRate) { - ++histo[data[i]]; - } - { - const size_t total = (len + kSampleRate - 1) / kSampleRate; - double r = (FastLog2(total) + 0.5) * (double)total + 200; - for (i = 0; i < 256; ++i) { - r -= (double)histo[i] * (depths[i] + FastLog2(histo[i])); - } - return TO_BROTLI_BOOL(r >= 0.0); - } -} - -/* Acceptable loss for uncompressible speedup is 2% */ -#define MIN_RATIO 980 - -static BROTLI_INLINE BROTLI_BOOL ShouldUseUncompressedMode( - const uint8_t* metablock_start, const uint8_t* next_emit, - const size_t insertlen, const size_t literal_ratio) { - const size_t compressed = (size_t)(next_emit - metablock_start); - if (compressed * 50 > insertlen) { - return BROTLI_FALSE; - } else { - return TO_BROTLI_BOOL(literal_ratio > MIN_RATIO); - } -} - -static void EmitUncompressedMetaBlock(const uint8_t* begin, const uint8_t* end, - const size_t storage_ix_start, - size_t* storage_ix, uint8_t* storage) { - const size_t len = (size_t)(end - begin); - RewindBitPosition(storage_ix_start, storage_ix, storage); - BrotliStoreMetaBlockHeader(len, 1, storage_ix, storage); - *storage_ix = (*storage_ix + 7u) & ~7u; - memcpy(&storage[*storage_ix >> 3], begin, len); - *storage_ix += len << 3; - storage[*storage_ix >> 3] = 0; -} - -static uint32_t kCmdHistoSeed[128] = { - 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 0, 0, 0, 0, -}; - -static BROTLI_INLINE void BrotliCompressFragmentFastImpl( - MemoryManager* m, const uint8_t* input, size_t input_size, - BROTLI_BOOL is_last, int* table, size_t table_bits, uint8_t cmd_depth[128], - uint16_t cmd_bits[128], size_t* cmd_code_numbits, uint8_t* cmd_code, - size_t* storage_ix, uint8_t* storage) { - uint32_t cmd_histo[128]; - const uint8_t* ip_end; - - /* "next_emit" is a pointer to the first byte that is not covered by a - previous copy. Bytes between "next_emit" and the start of the next copy or - the end of the input will be emitted as literal bytes. */ - const uint8_t* next_emit = input; - /* Save the start of the first block for position and distance computations. - */ - const uint8_t* base_ip = input; - - static const size_t kFirstBlockSize = 3 << 15; - static const size_t kMergeBlockSize = 1 << 16; - - const size_t kInputMarginBytes = BROTLI_WINDOW_GAP; - const size_t kMinMatchLen = 5; - - const uint8_t* metablock_start = input; - size_t block_size = BROTLI_MIN(size_t, input_size, kFirstBlockSize); - size_t total_block_size = block_size; - /* Save the bit position of the MLEN field of the meta-block header, so that - we can update it later if we decide to extend this meta-block. */ - size_t mlen_storage_ix = *storage_ix + 3; - - uint8_t lit_depth[256]; - uint16_t lit_bits[256]; - - size_t literal_ratio; - - const uint8_t* ip; - int last_distance; - - const size_t shift = 64u - table_bits; - - BrotliStoreMetaBlockHeader(block_size, 0, storage_ix, storage); - /* No block splits, no contexts. */ - BrotliWriteBits(13, 0, storage_ix, storage); - - literal_ratio = BuildAndStoreLiteralPrefixCode( - m, input, block_size, lit_depth, lit_bits, storage_ix, storage); - if (BROTLI_IS_OOM(m)) return; - - { - /* Store the pre-compressed command and distance prefix codes. */ - size_t i; - for (i = 0; i + 7 < *cmd_code_numbits; i += 8) { - BrotliWriteBits(8, cmd_code[i >> 3], storage_ix, storage); - } - } - BrotliWriteBits(*cmd_code_numbits & 7, cmd_code[*cmd_code_numbits >> 3], - storage_ix, storage); - - emit_commands: - /* Initialize the command and distance histograms. We will gather - statistics of command and distance codes during the processing - of this block and use it to update the command and distance - prefix codes for the next block. */ - memcpy(cmd_histo, kCmdHistoSeed, sizeof(kCmdHistoSeed)); - - /* "ip" is the input pointer. */ - ip = input; - last_distance = -1; - ip_end = input + block_size; - - if (BROTLI_PREDICT_TRUE(block_size >= kInputMarginBytes)) { - /* For the last block, we need to keep a 16 bytes margin so that we can be - sure that all distances are at most window size - 16. - For all other blocks, we only need to keep a margin of 5 bytes so that - we don't go over the block size with a copy. */ - const size_t len_limit = BROTLI_MIN(size_t, block_size - kMinMatchLen, - input_size - kInputMarginBytes); - const uint8_t* ip_limit = input + len_limit; - - uint32_t next_hash; - for (next_hash = Hash(++ip, shift); ; ) { - /* Step 1: Scan forward in the input looking for a 5-byte-long match. - If we get close to exhausting the input then goto emit_remainder. - - Heuristic match skipping: If 32 bytes are scanned with no matches - found, start looking only at every other byte. If 32 more bytes are - scanned, look at every third byte, etc.. When a match is found, - immediately go back to looking at every byte. This is a small loss - (~5% performance, ~0.1% density) for compressible data due to more - bookkeeping, but for non-compressible data (such as JPEG) it's a huge - win since the compressor quickly "realizes" the data is incompressible - and doesn't bother looking for matches everywhere. - - The "skip" variable keeps track of how many bytes there are since the - last match; dividing it by 32 (i.e. right-shifting by five) gives the - number of bytes to move ahead for each iteration. */ - uint32_t skip = 32; - - const uint8_t* next_ip = ip; - const uint8_t* candidate; - BROTLI_DCHECK(next_emit < ip); -trawl: - do { - uint32_t hash = next_hash; - uint32_t bytes_between_hash_lookups = skip++ >> 5; - BROTLI_DCHECK(hash == Hash(next_ip, shift)); - ip = next_ip; - next_ip = ip + bytes_between_hash_lookups; - if (BROTLI_PREDICT_FALSE(next_ip > ip_limit)) { - goto emit_remainder; - } - next_hash = Hash(next_ip, shift); - candidate = ip - last_distance; - if (IsMatch(ip, candidate)) { - if (BROTLI_PREDICT_TRUE(candidate < ip)) { - table[hash] = (int)(ip - base_ip); - break; - } - } - candidate = base_ip + table[hash]; - BROTLI_DCHECK(candidate >= base_ip); - BROTLI_DCHECK(candidate < ip); - - table[hash] = (int)(ip - base_ip); - } while (BROTLI_PREDICT_TRUE(!IsMatch(ip, candidate))); - - /* Check copy distance. If candidate is not feasible, continue search. - Checking is done outside of hot loop to reduce overhead. */ - if (ip - candidate > MAX_DISTANCE) goto trawl; - - /* Step 2: Emit the found match together with the literal bytes from - "next_emit" to the bit stream, and then see if we can find a next match - immediately afterwards. Repeat until we find no match for the input - without emitting some literal bytes. */ - - { - /* We have a 5-byte match at ip, and we need to emit bytes in - [next_emit, ip). */ - const uint8_t* base = ip; - size_t matched = 5 + FindMatchLengthWithLimit( - candidate + 5, ip + 5, (size_t)(ip_end - ip) - 5); - int distance = (int)(base - candidate); /* > 0 */ - size_t insert = (size_t)(base - next_emit); - ip += matched; - BROTLI_DCHECK(0 == memcmp(base, candidate, matched)); - if (BROTLI_PREDICT_TRUE(insert < 6210)) { - EmitInsertLen(insert, cmd_depth, cmd_bits, cmd_histo, - storage_ix, storage); - } else if (ShouldUseUncompressedMode(metablock_start, next_emit, insert, - literal_ratio)) { - EmitUncompressedMetaBlock(metablock_start, base, mlen_storage_ix - 3, - storage_ix, storage); - input_size -= (size_t)(base - input); - input = base; - next_emit = input; - goto next_block; - } else { - EmitLongInsertLen(insert, cmd_depth, cmd_bits, cmd_histo, - storage_ix, storage); - } - EmitLiterals(next_emit, insert, lit_depth, lit_bits, - storage_ix, storage); - if (distance == last_distance) { - BrotliWriteBits(cmd_depth[64], cmd_bits[64], storage_ix, storage); - ++cmd_histo[64]; - } else { - EmitDistance((size_t)distance, cmd_depth, cmd_bits, - cmd_histo, storage_ix, storage); - last_distance = distance; - } - EmitCopyLenLastDistance(matched, cmd_depth, cmd_bits, cmd_histo, - storage_ix, storage); - - next_emit = ip; - if (BROTLI_PREDICT_FALSE(ip >= ip_limit)) { - goto emit_remainder; - } - /* We could immediately start working at ip now, but to improve - compression we first update "table" with the hashes of some positions - within the last copy. */ - { - uint64_t input_bytes = BROTLI_UNALIGNED_LOAD64LE(ip - 3); - uint32_t prev_hash = HashBytesAtOffset(input_bytes, 0, shift); - uint32_t cur_hash = HashBytesAtOffset(input_bytes, 3, shift); - table[prev_hash] = (int)(ip - base_ip - 3); - prev_hash = HashBytesAtOffset(input_bytes, 1, shift); - table[prev_hash] = (int)(ip - base_ip - 2); - prev_hash = HashBytesAtOffset(input_bytes, 2, shift); - table[prev_hash] = (int)(ip - base_ip - 1); - - candidate = base_ip + table[cur_hash]; - table[cur_hash] = (int)(ip - base_ip); - } - } - - while (IsMatch(ip, candidate)) { - /* We have a 5-byte match at ip, and no need to emit any literal bytes - prior to ip. */ - const uint8_t* base = ip; - size_t matched = 5 + FindMatchLengthWithLimit( - candidate + 5, ip + 5, (size_t)(ip_end - ip) - 5); - if (ip - candidate > MAX_DISTANCE) break; - ip += matched; - last_distance = (int)(base - candidate); /* > 0 */ - BROTLI_DCHECK(0 == memcmp(base, candidate, matched)); - EmitCopyLen(matched, cmd_depth, cmd_bits, cmd_histo, - storage_ix, storage); - EmitDistance((size_t)last_distance, cmd_depth, cmd_bits, - cmd_histo, storage_ix, storage); - - next_emit = ip; - if (BROTLI_PREDICT_FALSE(ip >= ip_limit)) { - goto emit_remainder; - } - /* We could immediately start working at ip now, but to improve - compression we first update "table" with the hashes of some positions - within the last copy. */ - { - uint64_t input_bytes = BROTLI_UNALIGNED_LOAD64LE(ip - 3); - uint32_t prev_hash = HashBytesAtOffset(input_bytes, 0, shift); - uint32_t cur_hash = HashBytesAtOffset(input_bytes, 3, shift); - table[prev_hash] = (int)(ip - base_ip - 3); - prev_hash = HashBytesAtOffset(input_bytes, 1, shift); - table[prev_hash] = (int)(ip - base_ip - 2); - prev_hash = HashBytesAtOffset(input_bytes, 2, shift); - table[prev_hash] = (int)(ip - base_ip - 1); - - candidate = base_ip + table[cur_hash]; - table[cur_hash] = (int)(ip - base_ip); - } - } - - next_hash = Hash(++ip, shift); - } - } - - emit_remainder: - BROTLI_DCHECK(next_emit <= ip_end); - input += block_size; - input_size -= block_size; - block_size = BROTLI_MIN(size_t, input_size, kMergeBlockSize); - - /* Decide if we want to continue this meta-block instead of emitting the - last insert-only command. */ - if (input_size > 0 && - total_block_size + block_size <= (1 << 20) && - ShouldMergeBlock(input, block_size, lit_depth)) { - BROTLI_DCHECK(total_block_size > (1 << 16)); - /* Update the size of the current meta-block and continue emitting commands. - We can do this because the current size and the new size both have 5 - nibbles. */ - total_block_size += block_size; - UpdateBits(20, (uint32_t)(total_block_size - 1), mlen_storage_ix, storage); - goto emit_commands; - } - - /* Emit the remaining bytes as literals. */ - if (next_emit < ip_end) { - const size_t insert = (size_t)(ip_end - next_emit); - if (BROTLI_PREDICT_TRUE(insert < 6210)) { - EmitInsertLen(insert, cmd_depth, cmd_bits, cmd_histo, - storage_ix, storage); - EmitLiterals(next_emit, insert, lit_depth, lit_bits, storage_ix, storage); - } else if (ShouldUseUncompressedMode(metablock_start, next_emit, insert, - literal_ratio)) { - EmitUncompressedMetaBlock(metablock_start, ip_end, mlen_storage_ix - 3, - storage_ix, storage); - } else { - EmitLongInsertLen(insert, cmd_depth, cmd_bits, cmd_histo, - storage_ix, storage); - EmitLiterals(next_emit, insert, lit_depth, lit_bits, - storage_ix, storage); - } - } - next_emit = ip_end; - -next_block: - /* If we have more data, write a new meta-block header and prefix codes and - then continue emitting commands. */ - if (input_size > 0) { - metablock_start = input; - block_size = BROTLI_MIN(size_t, input_size, kFirstBlockSize); - total_block_size = block_size; - /* Save the bit position of the MLEN field of the meta-block header, so that - we can update it later if we decide to extend this meta-block. */ - mlen_storage_ix = *storage_ix + 3; - BrotliStoreMetaBlockHeader(block_size, 0, storage_ix, storage); - /* No block splits, no contexts. */ - BrotliWriteBits(13, 0, storage_ix, storage); - literal_ratio = BuildAndStoreLiteralPrefixCode( - m, input, block_size, lit_depth, lit_bits, storage_ix, storage); - if (BROTLI_IS_OOM(m)) return; - BuildAndStoreCommandPrefixCode(cmd_histo, cmd_depth, cmd_bits, - storage_ix, storage); - goto emit_commands; - } - - if (!is_last) { - /* If this is not the last block, update the command and distance prefix - codes for the next block and store the compressed forms. */ - cmd_code[0] = 0; - *cmd_code_numbits = 0; - BuildAndStoreCommandPrefixCode(cmd_histo, cmd_depth, cmd_bits, - cmd_code_numbits, cmd_code); - } -} - -#define FOR_TABLE_BITS_(X) X(9) X(11) X(13) X(15) - -#define BAKE_METHOD_PARAM_(B) \ -static BROTLI_NOINLINE void BrotliCompressFragmentFastImpl ## B( \ - MemoryManager* m, const uint8_t* input, size_t input_size, \ - BROTLI_BOOL is_last, int* table, uint8_t cmd_depth[128], \ - uint16_t cmd_bits[128], size_t* cmd_code_numbits, uint8_t* cmd_code, \ - size_t* storage_ix, uint8_t* storage) { \ - BrotliCompressFragmentFastImpl(m, input, input_size, is_last, table, B, \ - cmd_depth, cmd_bits, cmd_code_numbits, cmd_code, storage_ix, storage); \ -} -FOR_TABLE_BITS_(BAKE_METHOD_PARAM_) -#undef BAKE_METHOD_PARAM_ - -void BrotliCompressFragmentFast( - MemoryManager* m, const uint8_t* input, size_t input_size, - BROTLI_BOOL is_last, int* table, size_t table_size, uint8_t cmd_depth[128], - uint16_t cmd_bits[128], size_t* cmd_code_numbits, uint8_t* cmd_code, - size_t* storage_ix, uint8_t* storage) { - const size_t initial_storage_ix = *storage_ix; - const size_t table_bits = Log2FloorNonZero(table_size); - - if (input_size == 0) { - BROTLI_DCHECK(is_last); - BrotliWriteBits(1, 1, storage_ix, storage); /* islast */ - BrotliWriteBits(1, 1, storage_ix, storage); /* isempty */ - *storage_ix = (*storage_ix + 7u) & ~7u; - return; - } - - switch (table_bits) { -#define CASE_(B) \ - case B: \ - BrotliCompressFragmentFastImpl ## B( \ - m, input, input_size, is_last, table, cmd_depth, cmd_bits, \ - cmd_code_numbits, cmd_code, storage_ix, storage); \ - break; - FOR_TABLE_BITS_(CASE_) -#undef CASE_ - default: BROTLI_DCHECK(0); break; - } - - /* If output is larger than single uncompressed block, rewrite it. */ - if (*storage_ix - initial_storage_ix > 31 + (input_size << 3)) { - EmitUncompressedMetaBlock(input, input + input_size, initial_storage_ix, - storage_ix, storage); - } - - if (is_last) { - BrotliWriteBits(1, 1, storage_ix, storage); /* islast */ - BrotliWriteBits(1, 1, storage_ix, storage); /* isempty */ - *storage_ix = (*storage_ix + 7u) & ~7u; - } -} - -#undef FOR_TABLE_BITS_ - -#if defined(__cplusplus) || defined(c_plusplus) -} /* extern "C" */ -#endif |