diff options
Diffstat (limited to 'deps/node/deps/brotli/c/enc/compress_fragment_two_pass.c')
| -rw-r--r-- | deps/node/deps/brotli/c/enc/compress_fragment_two_pass.c | 645 |
1 files changed, 0 insertions, 645 deletions
diff --git a/deps/node/deps/brotli/c/enc/compress_fragment_two_pass.c b/deps/node/deps/brotli/c/enc/compress_fragment_two_pass.c deleted file mode 100644 index f8a56063..00000000 --- a/deps/node/deps/brotli/c/enc/compress_fragment_two_pass.c +++ /dev/null @@ -1,645 +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 two-pass processing: in the first pass we save - the found backward matches and literal bytes into a buffer, and in the - second pass we emit them into the bit stream using prefix codes built based - on the actual command and literal byte histograms. */ - -#include "./compress_fragment_two_pass.h" - -#include <string.h> /* memcmp, memcpy, memset */ - -#include "../common/constants.h" -#include "../common/platform.h" -#include <brotli/types.h> -#include "./bit_cost.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, size_t length) { - const uint64_t h = - (BROTLI_UNALIGNED_LOAD64LE(p) << ((8 - length) * 8)) * kHashMul32; - return (uint32_t)(h >> shift); -} - -static BROTLI_INLINE uint32_t HashBytesAtOffset(uint64_t v, size_t offset, - size_t shift, size_t length) { - BROTLI_DCHECK(offset <= 8 - length); - { - const uint64_t h = ((v >> (8 * offset)) << ((8 - length) * 8)) * kHashMul32; - return (uint32_t)(h >> shift); - } -} - -static BROTLI_INLINE BROTLI_BOOL IsMatch(const uint8_t* p1, const uint8_t* p2, - size_t length) { - if (BrotliUnalignedRead32(p1) == BrotliUnalignedRead32(p2)) { - if (length == 4) return BROTLI_TRUE; - return TO_BROTLI_BOOL(p1[4] == p2[4] && p1[5] == p2[5]); - } - return BROTLI_FALSE; -} - -/* 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, 24); - memcpy(cmd_depth + 24, depth, 8); - memcpy(cmd_depth + 32, depth + 48, 8); - memcpy(cmd_depth + 40, depth + 8, 8); - memcpy(cmd_depth + 48, depth + 56, 8); - memcpy(cmd_depth + 56, depth + 16, 8); - BrotliConvertBitDepthsToSymbols(cmd_depth, 64, cmd_bits); - memcpy(bits, cmd_bits + 24, 16); - memcpy(bits + 8, cmd_bits + 40, 16); - memcpy(bits + 16, cmd_bits + 56, 16); - memcpy(bits + 24, cmd_bits, 48); - memcpy(bits + 48, cmd_bits + 32, 16); - memcpy(bits + 56, cmd_bits + 48, 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 + 24, 8); - memcpy(cmd_depth + 64, depth + 32, 8); - memcpy(cmd_depth + 128, depth + 40, 8); - memcpy(cmd_depth + 192, depth + 48, 8); - memcpy(cmd_depth + 384, depth + 56, 8); - for (i = 0; i < 8; ++i) { - cmd_depth[128 + 8 * i] = depth[i]; - cmd_depth[256 + 8 * i] = depth[8 + i]; - cmd_depth[448 + 8 * i] = depth[16 + i]; - } - BrotliStoreHuffmanTree( - cmd_depth, BROTLI_NUM_COMMAND_SYMBOLS, tree, storage_ix, storage); - } - BrotliStoreHuffmanTree(&depth[64], 64, tree, storage_ix, storage); -} - -static BROTLI_INLINE void EmitInsertLen( - uint32_t insertlen, uint32_t** commands) { - if (insertlen < 6) { - **commands = insertlen; - } else if (insertlen < 130) { - const uint32_t tail = insertlen - 2; - const uint32_t nbits = Log2FloorNonZero(tail) - 1u; - const uint32_t prefix = tail >> nbits; - const uint32_t inscode = (nbits << 1) + prefix + 2; - const uint32_t extra = tail - (prefix << nbits); - **commands = inscode | (extra << 8); - } else if (insertlen < 2114) { - const uint32_t tail = insertlen - 66; - const uint32_t nbits = Log2FloorNonZero(tail); - const uint32_t code = nbits + 10; - const uint32_t extra = tail - (1u << nbits); - **commands = code | (extra << 8); - } else if (insertlen < 6210) { - const uint32_t extra = insertlen - 2114; - **commands = 21 | (extra << 8); - } else if (insertlen < 22594) { - const uint32_t extra = insertlen - 6210; - **commands = 22 | (extra << 8); - } else { - const uint32_t extra = insertlen - 22594; - **commands = 23 | (extra << 8); - } - ++(*commands); -} - -static BROTLI_INLINE void EmitCopyLen(size_t copylen, uint32_t** commands) { - if (copylen < 10) { - **commands = (uint32_t)(copylen + 38); - } else if (copylen < 134) { - const size_t tail = copylen - 6; - const size_t nbits = Log2FloorNonZero(tail) - 1; - const size_t prefix = tail >> nbits; - const size_t code = (nbits << 1) + prefix + 44; - const size_t extra = tail - (prefix << nbits); - **commands = (uint32_t)(code | (extra << 8)); - } else if (copylen < 2118) { - const size_t tail = copylen - 70; - const size_t nbits = Log2FloorNonZero(tail); - const size_t code = nbits + 52; - const size_t extra = tail - ((size_t)1 << nbits); - **commands = (uint32_t)(code | (extra << 8)); - } else { - const size_t extra = copylen - 2118; - **commands = (uint32_t)(63 | (extra << 8)); - } - ++(*commands); -} - -static BROTLI_INLINE void EmitCopyLenLastDistance( - size_t copylen, uint32_t** commands) { - if (copylen < 12) { - **commands = (uint32_t)(copylen + 20); - ++(*commands); - } else if (copylen < 72) { - const size_t tail = copylen - 8; - const size_t nbits = Log2FloorNonZero(tail) - 1; - const size_t prefix = tail >> nbits; - const size_t code = (nbits << 1) + prefix + 28; - const size_t extra = tail - (prefix << nbits); - **commands = (uint32_t)(code | (extra << 8)); - ++(*commands); - } else if (copylen < 136) { - const size_t tail = copylen - 8; - const size_t code = (tail >> 5) + 54; - const size_t extra = tail & 31; - **commands = (uint32_t)(code | (extra << 8)); - ++(*commands); - **commands = 64; - ++(*commands); - } else if (copylen < 2120) { - const size_t tail = copylen - 72; - const size_t nbits = Log2FloorNonZero(tail); - const size_t code = nbits + 52; - const size_t extra = tail - ((size_t)1 << nbits); - **commands = (uint32_t)(code | (extra << 8)); - ++(*commands); - **commands = 64; - ++(*commands); - } else { - const size_t extra = copylen - 2120; - **commands = (uint32_t)(63 | (extra << 8)); - ++(*commands); - **commands = 64; - ++(*commands); - } -} - -static BROTLI_INLINE void EmitDistance(uint32_t distance, uint32_t** commands) { - uint32_t d = distance + 3; - uint32_t nbits = Log2FloorNonZero(d) - 1; - const uint32_t prefix = (d >> nbits) & 1; - const uint32_t offset = (2 + prefix) << nbits; - const uint32_t distcode = 2 * (nbits - 1) + prefix + 80; - uint32_t extra = d - offset; - **commands = distcode | (extra << 8); - ++(*commands); -} - -/* 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 BROTLI_INLINE void CreateCommands(const uint8_t* input, - size_t block_size, size_t input_size, const uint8_t* base_ip, int* table, - size_t table_bits, size_t min_match, - uint8_t** literals, uint32_t** commands) { - /* "ip" is the input pointer. */ - const uint8_t* ip = input; - const size_t shift = 64u - table_bits; - const uint8_t* ip_end = input + block_size; - /* "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; - - int last_distance = -1; - const size_t kInputMarginBytes = BROTLI_WINDOW_GAP; - - 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 - min_match, - input_size - kInputMarginBytes); - const uint8_t* ip_limit = input + len_limit; - - uint32_t next_hash; - for (next_hash = Hash(++ip, shift, min_match); ; ) { - /* Step 1: Scan forward in the input looking for a 6-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 (ie. 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; - ip = next_ip; - BROTLI_DCHECK(hash == Hash(ip, shift, min_match)); - next_ip = ip + bytes_between_hash_lookups; - if (BROTLI_PREDICT_FALSE(next_ip > ip_limit)) { - goto emit_remainder; - } - next_hash = Hash(next_ip, shift, min_match); - candidate = ip - last_distance; - if (IsMatch(ip, candidate, min_match)) { - 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, min_match))); - - /* 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", 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 6-byte match at ip, and we need to emit bytes in - [next_emit, ip). */ - const uint8_t* base = ip; - size_t matched = min_match + FindMatchLengthWithLimit( - candidate + min_match, ip + min_match, - (size_t)(ip_end - ip) - min_match); - int distance = (int)(base - candidate); /* > 0 */ - int insert = (int)(base - next_emit); - ip += matched; - BROTLI_DCHECK(0 == memcmp(base, candidate, matched)); - EmitInsertLen((uint32_t)insert, commands); - memcpy(*literals, next_emit, (size_t)insert); - *literals += insert; - if (distance == last_distance) { - **commands = 64; - ++(*commands); - } else { - EmitDistance((uint32_t)distance, commands); - last_distance = distance; - } - EmitCopyLenLastDistance(matched, commands); - - 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; - uint32_t cur_hash; - uint32_t prev_hash; - if (min_match == 4) { - input_bytes = BROTLI_UNALIGNED_LOAD64LE(ip - 3); - cur_hash = HashBytesAtOffset(input_bytes, 3, shift, min_match); - prev_hash = HashBytesAtOffset(input_bytes, 0, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 3); - prev_hash = HashBytesAtOffset(input_bytes, 1, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 2); - prev_hash = HashBytesAtOffset(input_bytes, 0, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 1); - } else { - input_bytes = BROTLI_UNALIGNED_LOAD64LE(ip - 5); - prev_hash = HashBytesAtOffset(input_bytes, 0, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 5); - prev_hash = HashBytesAtOffset(input_bytes, 1, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 4); - prev_hash = HashBytesAtOffset(input_bytes, 2, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 3); - input_bytes = BROTLI_UNALIGNED_LOAD64LE(ip - 2); - cur_hash = HashBytesAtOffset(input_bytes, 2, shift, min_match); - prev_hash = HashBytesAtOffset(input_bytes, 0, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 2); - prev_hash = HashBytesAtOffset(input_bytes, 1, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 1); - } - - candidate = base_ip + table[cur_hash]; - table[cur_hash] = (int)(ip - base_ip); - } - } - - while (ip - candidate <= MAX_DISTANCE && - IsMatch(ip, candidate, min_match)) { - /* We have a 6-byte match at ip, and no need to emit any - literal bytes prior to ip. */ - const uint8_t* base = ip; - size_t matched = min_match + FindMatchLengthWithLimit( - candidate + min_match, ip + min_match, - (size_t)(ip_end - ip) - min_match); - ip += matched; - last_distance = (int)(base - candidate); /* > 0 */ - BROTLI_DCHECK(0 == memcmp(base, candidate, matched)); - EmitCopyLen(matched, commands); - EmitDistance((uint32_t)last_distance, commands); - - 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; - uint32_t cur_hash; - uint32_t prev_hash; - if (min_match == 4) { - input_bytes = BROTLI_UNALIGNED_LOAD64LE(ip - 3); - cur_hash = HashBytesAtOffset(input_bytes, 3, shift, min_match); - prev_hash = HashBytesAtOffset(input_bytes, 0, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 3); - prev_hash = HashBytesAtOffset(input_bytes, 1, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 2); - prev_hash = HashBytesAtOffset(input_bytes, 2, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 1); - } else { - input_bytes = BROTLI_UNALIGNED_LOAD64LE(ip - 5); - prev_hash = HashBytesAtOffset(input_bytes, 0, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 5); - prev_hash = HashBytesAtOffset(input_bytes, 1, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 4); - prev_hash = HashBytesAtOffset(input_bytes, 2, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 3); - input_bytes = BROTLI_UNALIGNED_LOAD64LE(ip - 2); - cur_hash = HashBytesAtOffset(input_bytes, 2, shift, min_match); - prev_hash = HashBytesAtOffset(input_bytes, 0, shift, min_match); - table[prev_hash] = (int)(ip - base_ip - 2); - prev_hash = HashBytesAtOffset(input_bytes, 1, shift, min_match); - 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, min_match); - } - } - -emit_remainder: - BROTLI_DCHECK(next_emit <= ip_end); - /* Emit the remaining bytes as literals. */ - if (next_emit < ip_end) { - const uint32_t insert = (uint32_t)(ip_end - next_emit); - EmitInsertLen(insert, commands); - memcpy(*literals, next_emit, insert); - *literals += insert; - } -} - -static void StoreCommands(MemoryManager* m, - const uint8_t* literals, const size_t num_literals, - const uint32_t* commands, const size_t num_commands, - size_t* storage_ix, uint8_t* storage) { - static const uint32_t kNumExtraBits[128] = { - 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 7, 8, 9, 10, 12, 14, 24, - 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, - 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 7, 8, 9, 10, 24, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, - 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, - 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, - }; - static const uint32_t kInsertOffset[24] = { - 0, 1, 2, 3, 4, 5, 6, 8, 10, 14, 18, 26, 34, 50, 66, 98, 130, 194, 322, 578, - 1090, 2114, 6210, 22594, - }; - - uint8_t lit_depths[256]; - uint16_t lit_bits[256]; - uint32_t lit_histo[256] = { 0 }; - uint8_t cmd_depths[128] = { 0 }; - uint16_t cmd_bits[128] = { 0 }; - uint32_t cmd_histo[128] = { 0 }; - size_t i; - for (i = 0; i < num_literals; ++i) { - ++lit_histo[literals[i]]; - } - BrotliBuildAndStoreHuffmanTreeFast(m, lit_histo, num_literals, - /* max_bits = */ 8, - lit_depths, lit_bits, - storage_ix, storage); - if (BROTLI_IS_OOM(m)) return; - - for (i = 0; i < num_commands; ++i) { - const uint32_t code = commands[i] & 0xFF; - BROTLI_DCHECK(code < 128); - ++cmd_histo[code]; - } - cmd_histo[1] += 1; - cmd_histo[2] += 1; - cmd_histo[64] += 1; - cmd_histo[84] += 1; - BuildAndStoreCommandPrefixCode(cmd_histo, cmd_depths, cmd_bits, - storage_ix, storage); - - for (i = 0; i < num_commands; ++i) { - const uint32_t cmd = commands[i]; - const uint32_t code = cmd & 0xFF; - const uint32_t extra = cmd >> 8; - BROTLI_DCHECK(code < 128); - BrotliWriteBits(cmd_depths[code], cmd_bits[code], storage_ix, storage); - BrotliWriteBits(kNumExtraBits[code], extra, storage_ix, storage); - if (code < 24) { - const uint32_t insert = kInsertOffset[code] + extra; - uint32_t j; - for (j = 0; j < insert; ++j) { - const uint8_t lit = *literals; - BrotliWriteBits(lit_depths[lit], lit_bits[lit], storage_ix, storage); - ++literals; - } - } - } -} - -/* Acceptable loss for uncompressible speedup is 2% */ -#define MIN_RATIO 0.98 -#define SAMPLE_RATE 43 - -static BROTLI_BOOL ShouldCompress( - const uint8_t* input, size_t input_size, size_t num_literals) { - double corpus_size = (double)input_size; - if (num_literals < MIN_RATIO * corpus_size) { - return BROTLI_TRUE; - } else { - uint32_t literal_histo[256] = { 0 }; - const double max_total_bit_cost = corpus_size * 8 * MIN_RATIO / SAMPLE_RATE; - size_t i; - for (i = 0; i < input_size; i += SAMPLE_RATE) { - ++literal_histo[input[i]]; - } - return TO_BROTLI_BOOL(BitsEntropy(literal_histo, 256) < max_total_bit_cost); - } -} - -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 void EmitUncompressedMetaBlock(const uint8_t* input, size_t input_size, - size_t* storage_ix, uint8_t* storage) { - BrotliStoreMetaBlockHeader(input_size, 1, storage_ix, storage); - *storage_ix = (*storage_ix + 7u) & ~7u; - memcpy(&storage[*storage_ix >> 3], input, input_size); - *storage_ix += input_size << 3; - storage[*storage_ix >> 3] = 0; -} - -static BROTLI_INLINE void BrotliCompressFragmentTwoPassImpl( - MemoryManager* m, const uint8_t* input, size_t input_size, - BROTLI_BOOL is_last, uint32_t* command_buf, uint8_t* literal_buf, - int* table, size_t table_bits, size_t min_match, - size_t* storage_ix, uint8_t* storage) { - /* Save the start of the first block for position and distance computations. - */ - const uint8_t* base_ip = input; - BROTLI_UNUSED(is_last); - - while (input_size > 0) { - size_t block_size = - BROTLI_MIN(size_t, input_size, kCompressFragmentTwoPassBlockSize); - uint32_t* commands = command_buf; - uint8_t* literals = literal_buf; - size_t num_literals; - CreateCommands(input, block_size, input_size, base_ip, table, - table_bits, min_match, &literals, &commands); - num_literals = (size_t)(literals - literal_buf); - if (ShouldCompress(input, block_size, num_literals)) { - const size_t num_commands = (size_t)(commands - command_buf); - BrotliStoreMetaBlockHeader(block_size, 0, storage_ix, storage); - /* No block splits, no contexts. */ - BrotliWriteBits(13, 0, storage_ix, storage); - StoreCommands(m, literal_buf, num_literals, command_buf, num_commands, - storage_ix, storage); - if (BROTLI_IS_OOM(m)) return; - } else { - /* Since we did not find many backward references and the entropy of - the data is close to 8 bits, we can simply emit an uncompressed block. - This makes compression speed of uncompressible data about 3x faster. */ - EmitUncompressedMetaBlock(input, block_size, storage_ix, storage); - } - input += block_size; - input_size -= block_size; - } -} - -#define FOR_TABLE_BITS_(X) \ - X(8) X(9) X(10) X(11) X(12) X(13) X(14) X(15) X(16) X(17) - -#define BAKE_METHOD_PARAM_(B) \ -static BROTLI_NOINLINE void BrotliCompressFragmentTwoPassImpl ## B( \ - MemoryManager* m, const uint8_t* input, size_t input_size, \ - BROTLI_BOOL is_last, uint32_t* command_buf, uint8_t* literal_buf, \ - int* table, size_t* storage_ix, uint8_t* storage) { \ - size_t min_match = (B <= 15) ? 4 : 6; \ - BrotliCompressFragmentTwoPassImpl(m, input, input_size, is_last, command_buf,\ - literal_buf, table, B, min_match, storage_ix, storage); \ -} -FOR_TABLE_BITS_(BAKE_METHOD_PARAM_) -#undef BAKE_METHOD_PARAM_ - -void BrotliCompressFragmentTwoPass( - MemoryManager* m, const uint8_t* input, size_t input_size, - BROTLI_BOOL is_last, uint32_t* command_buf, uint8_t* literal_buf, - int* table, size_t table_size, size_t* storage_ix, uint8_t* storage) { - const size_t initial_storage_ix = *storage_ix; - const size_t table_bits = Log2FloorNonZero(table_size); - switch (table_bits) { -#define CASE_(B) \ - case B: \ - BrotliCompressFragmentTwoPassImpl ## B( \ - m, input, input_size, is_last, command_buf, \ - literal_buf, table, 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)) { - RewindBitPosition(initial_storage_ix, storage_ix, storage); - EmitUncompressedMetaBlock(input, input_size, 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 |