Update brotli to v1.0.0-snapshot.

third_party/brotli/enc/compress_fragment_two_pass.c

+/* 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 <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 "./port.h"
+#include "./write_bits.h"
+
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+/* Same as MaxBackwardLimit(18) */
+#define MAX_DISTANCE ((1 << 18) - BROTLI_WINDOW_GAP)
+
+/* 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_LOAD64(p) << 16) * kHashMul32;
+  return (uint32_t)(h >> shift);
+}
+
+static BROTLI_INLINE uint32_t HashBytesAtOffset(
+    uint64_t v, int offset, size_t shift) {
+  assert(offset >= 0);
+  assert(offset <= 2);
+  {
+    const uint64_t h = ((v >> (8 * offset)) << 16) * kHashMul32;
+    return (uint32_t)(h >> shift);
+  }
+}
+
+static BROTLI_INLINE BROTLI_BOOL IsMatch(const uint8_t* p1, const uint8_t* p2) {
+  return TO_BROTLI_BOOL(
+      BROTLI_UNALIGNED_LOAD32(p1) == BROTLI_UNALIGNED_LOAD32(p2) &&
+      p1[4] == p2[4] &&
+      p1[5] == p2[5]);
+}
+
+/* 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 << 20. */
+static void BrotliStoreMetaBlockHeader(
+    size_t len, BROTLI_BOOL is_uncompressed, size_t* storage_ix,
+    uint8_t* storage) {
+  /* ISLAST */
+  BrotliWriteBits(1, 0, storage_ix, storage);
+  if (len <= (1U << 16)) {
+    /* MNIBBLES is 4 */
+    BrotliWriteBits(2, 0, storage_ix, storage);
+    BrotliWriteBits(16, len - 1, storage_ix, storage);
+  } else {
+    /* MNIBBLES is 5 */
+    BrotliWriteBits(2, 1, storage_ix, storage);
+    BrotliWriteBits(20, 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, 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;
+  const size_t kMinMatchLen = 6;
+
+  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 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;
+
+      assert(next_emit < ip);
+trawl:
+      do {
+        uint32_t hash = next_hash;
+        uint32_t bytes_between_hash_lookups = skip++ >> 5;
+        ip = next_ip;
+        assert(hash == Hash(ip, shift));
+        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];
+        assert(candidate >= base_ip);
+        assert(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", 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 = 6 + FindMatchLengthWithLimit(
+            candidate + 6, ip + 6, (size_t)(ip_end - ip) - 6);
+        int distance = (int)(base - candidate);  /* > 0 */
+        int insert = (int)(base - next_emit);
+        ip += matched;
+        assert(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 = BROTLI_UNALIGNED_LOAD64(ip - 5);
+          uint32_t prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
+          uint32_t cur_hash;
+          table[prev_hash] = (int)(ip - base_ip - 5);
+          prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
+          table[prev_hash] = (int)(ip - base_ip - 4);
+          prev_hash = HashBytesAtOffset(input_bytes, 2, shift);
+          table[prev_hash] = (int)(ip - base_ip - 3);
+          input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 2);
+          cur_hash = HashBytesAtOffset(input_bytes, 2, shift);
+          prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
+          table[prev_hash] = (int)(ip - base_ip - 2);
+          prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
+          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)) {
+        /* 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 = 6 + FindMatchLengthWithLimit(
+            candidate + 6, ip + 6, (size_t)(ip_end - ip) - 6);
+        ip += matched;
+        last_distance = (int)(base - candidate);  /* > 0 */
+        assert(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 = BROTLI_UNALIGNED_LOAD64(ip - 5);
+          uint32_t prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
+          uint32_t cur_hash;
+          table[prev_hash] = (int)(ip - base_ip - 5);
+          prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
+          table[prev_hash] = (int)(ip - base_ip - 4);
+          prev_hash = HashBytesAtOffset(input_bytes, 2, shift);
+          table[prev_hash] = (int)(ip - base_ip - 3);
+          input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 2);
+          cur_hash = HashBytesAtOffset(input_bytes, 2, shift);
+          prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
+          table[prev_hash] = (int)(ip - base_ip - 2);
+          prev_hash = HashBytesAtOffset(input_bytes, 1, 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:
+  assert(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) {
+    ++cmd_histo[commands[i] & 0xff];
+  }
+  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;
+    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 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* storage_ix, uint8_t* storage) {
+  /* Save the start of the first block for position and distance computations.
+  */
+  const uint8_t* base_ip = input;
+
+  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,
+                   &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. */
+      BrotliStoreMetaBlockHeader(block_size, 1, storage_ix, storage);
+      *storage_ix = (*storage_ix + 7u) & ~7u;
+      memcpy(&storage[*storage_ix >> 3], input, block_size);
+      *storage_ix += block_size << 3;
+      storage[*storage_ix >> 3] = 0;
+    }
+    input += block_size;
+    input_size -= block_size;
+  }
+
+  if (is_last) {
+    BrotliWriteBits(1, 1, storage_ix, storage);  /* islast */
+    BrotliWriteBits(1, 1, storage_ix, storage);  /* isempty */
+    *storage_ix = (*storage_ix + 7u) & ~7u;
+  }
+}
+
+#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) {                        \
+  BrotliCompressFragmentTwoPassImpl(m, input, input_size, is_last, command_buf,\
+      literal_buf, table, B, 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 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: assert(0); break;
+  }
+}
+
+#undef FOR_TABLE_BITS_
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}  /* extern "C" */
+#endif