Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2608 insertions, 0 deletions

diff --git a/modules/brotli/dec/decode.c b/modules/brotli/dec/decode.c
new file mode 100644
index 0000000000..ae5a3d3fa3
--- /dev/null
+++ b/modules/brotli/dec/decode.c
@@ -0,0 +1,2608 @@
+/* Copyright 2013 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+#include <brotli/decode.h>
+
+#include <stdlib.h>  /* free, malloc */
+#include <string.h>  /* memcpy, memset */
+
+#include "../common/constants.h"
+#include "../common/context.h"
+#include "../common/dictionary.h"
+#include "../common/platform.h"
+#include "../common/transform.h"
+#include "../common/version.h"
+#include "./bit_reader.h"
+#include "./huffman.h"
+#include "./prefix.h"
+#include "./state.h"
+
+#if defined(BROTLI_TARGET_NEON)
+#include <arm_neon.h>
+#endif
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+#define BROTLI_FAILURE(CODE) (BROTLI_DUMP(), CODE)
+
+#define BROTLI_LOG_UINT(name)                                       \
+  BROTLI_LOG(("[%s] %s = %lu\n", __func__, #name, (unsigned long)(name)))
+#define BROTLI_LOG_ARRAY_INDEX(array_name, idx)                     \
+  BROTLI_LOG(("[%s] %s[%lu] = %lu\n", __func__, #array_name,        \
+         (unsigned long)(idx), (unsigned long)array_name[idx]))
+
+#define HUFFMAN_TABLE_BITS 8U
+#define HUFFMAN_TABLE_MASK 0xFF
+
+/* We need the slack region for the following reasons:
+    - doing up to two 16-byte copies for fast backward copying
+    - inserting transformed dictionary word:
+        5 prefix + 24 base + 8 suffix */
+static const uint32_t kRingBufferWriteAheadSlack = 42;
+
+static const uint8_t kCodeLengthCodeOrder[BROTLI_CODE_LENGTH_CODES] = {
+  1, 2, 3, 4, 0, 5, 17, 6, 16, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+};
+
+/* Static prefix code for the complex code length code lengths. */
+static const uint8_t kCodeLengthPrefixLength[16] = {
+  2, 2, 2, 3, 2, 2, 2, 4, 2, 2, 2, 3, 2, 2, 2, 4,
+};
+
+static const uint8_t kCodeLengthPrefixValue[16] = {
+  0, 4, 3, 2, 0, 4, 3, 1, 0, 4, 3, 2, 0, 4, 3, 5,
+};
+
+BROTLI_BOOL BrotliDecoderSetParameter(
+    BrotliDecoderState* state, BrotliDecoderParameter p, uint32_t value) {
+  if (state->state != BROTLI_STATE_UNINITED) return BROTLI_FALSE;
+  switch (p) {
+    case BROTLI_DECODER_PARAM_DISABLE_RING_BUFFER_REALLOCATION:
+      state->canny_ringbuffer_allocation = !!value ? 0 : 1;
+      return BROTLI_TRUE;
+
+    case BROTLI_DECODER_PARAM_LARGE_WINDOW:
+      state->large_window = TO_BROTLI_BOOL(!!value);
+      return BROTLI_TRUE;
+
+    default: return BROTLI_FALSE;
+  }
+}
+
+BrotliDecoderState* BrotliDecoderCreateInstance(
+    brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque) {
+  BrotliDecoderState* state = 0;
+  if (!alloc_func && !free_func) {
+    state = (BrotliDecoderState*)malloc(sizeof(BrotliDecoderState));
+  } else if (alloc_func && free_func) {
+    state = (BrotliDecoderState*)alloc_func(opaque, sizeof(BrotliDecoderState));
+  }
+  if (state == 0) {
+    BROTLI_DUMP();
+    return 0;
+  }
+  if (!BrotliDecoderStateInit(state, alloc_func, free_func, opaque)) {
+    BROTLI_DUMP();
+    if (!alloc_func && !free_func) {
+      free(state);
+    } else if (alloc_func && free_func) {
+      free_func(opaque, state);
+    }
+    return 0;
+  }
+  return state;
+}
+
+/* Deinitializes and frees BrotliDecoderState instance. */
+void BrotliDecoderDestroyInstance(BrotliDecoderState* state) {
+  if (!state) {
+    return;
+  } else {
+    brotli_free_func free_func = state->free_func;
+    void* opaque = state->memory_manager_opaque;
+    BrotliDecoderStateCleanup(state);
+    free_func(opaque, state);
+  }
+}
+
+/* Saves error code and converts it to BrotliDecoderResult. */
+static BROTLI_NOINLINE BrotliDecoderResult SaveErrorCode(
+    BrotliDecoderState* s, BrotliDecoderErrorCode e) {
+  s->error_code = (int)e;
+  switch (e) {
+    case BROTLI_DECODER_SUCCESS:
+      return BROTLI_DECODER_RESULT_SUCCESS;
+
+    case BROTLI_DECODER_NEEDS_MORE_INPUT:
+      return BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT;
+
+    case BROTLI_DECODER_NEEDS_MORE_OUTPUT:
+      return BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT;
+
+    default:
+      return BROTLI_DECODER_RESULT_ERROR;
+  }
+}
+
+/* Decodes WBITS by reading 1 - 7 bits, or 0x11 for "Large Window Brotli".
+   Precondition: bit-reader accumulator has at least 8 bits. */
+static BrotliDecoderErrorCode DecodeWindowBits(BrotliDecoderState* s,
+                                               BrotliBitReader* br) {
+  uint32_t n;
+  BROTLI_BOOL large_window = s->large_window;
+  s->large_window = BROTLI_FALSE;
+  BrotliTakeBits(br, 1, &n);
+  if (n == 0) {
+    s->window_bits = 16;
+    return BROTLI_DECODER_SUCCESS;
+  }
+  BrotliTakeBits(br, 3, &n);
+  if (n != 0) {
+    s->window_bits = 17 + n;
+    return BROTLI_DECODER_SUCCESS;
+  }
+  BrotliTakeBits(br, 3, &n);
+  if (n == 1) {
+    if (large_window) {
+      BrotliTakeBits(br, 1, &n);
+      if (n == 1) {
+        return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS);
+      }
+      s->large_window = BROTLI_TRUE;
+      return BROTLI_DECODER_SUCCESS;
+    } else {
+      return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS);
+    }
+  }
+  if (n != 0) {
+    s->window_bits = 8 + n;
+    return BROTLI_DECODER_SUCCESS;
+  }
+  s->window_bits = 17;
+  return BROTLI_DECODER_SUCCESS;
+}
+
+static BROTLI_INLINE void memmove16(uint8_t* dst, uint8_t* src) {
+#if defined(BROTLI_TARGET_NEON)
+  vst1q_u8(dst, vld1q_u8(src));
+#else
+  uint32_t buffer[4];
+  memcpy(buffer, src, 16);
+  memcpy(dst, buffer, 16);
+#endif
+}
+
+/* Decodes a number in the range [0..255], by reading 1 - 11 bits. */
+static BROTLI_NOINLINE BrotliDecoderErrorCode DecodeVarLenUint8(
+    BrotliDecoderState* s, BrotliBitReader* br, uint32_t* value) {
+  uint32_t bits;
+  switch (s->substate_decode_uint8) {
+    case BROTLI_STATE_DECODE_UINT8_NONE:
+      if (BROTLI_PREDICT_FALSE(!BrotliSafeReadBits(br, 1, &bits))) {
+        return BROTLI_DECODER_NEEDS_MORE_INPUT;
+      }
+      if (bits == 0) {
+        *value = 0;
+        return BROTLI_DECODER_SUCCESS;
+      }
+    /* Fall through. */
+
+    case BROTLI_STATE_DECODE_UINT8_SHORT:
+      if (BROTLI_PREDICT_FALSE(!BrotliSafeReadBits(br, 3, &bits))) {
+        s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_SHORT;
+        return BROTLI_DECODER_NEEDS_MORE_INPUT;
+      }
+      if (bits == 0) {
+        *value = 1;
+        s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE;
+        return BROTLI_DECODER_SUCCESS;
+      }
+      /* Use output value as a temporary storage. It MUST be persisted. */
+      *value = bits;
+    /* Fall through. */
+
+    case BROTLI_STATE_DECODE_UINT8_LONG:
+      if (BROTLI_PREDICT_FALSE(!BrotliSafeReadBits(br, *value, &bits))) {
+        s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_LONG;
+        return BROTLI_DECODER_NEEDS_MORE_INPUT;
+      }
+      *value = (1U << *value) + bits;
+      s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE;
+      return BROTLI_DECODER_SUCCESS;
+
+    default:
+      return
+          BROTLI_FAILURE(BROTLI_DECODER_ERROR_UNREACHABLE);
+  }
+}
+
+/* Decodes a metablock length and flags by reading 2 - 31 bits. */
+static BrotliDecoderErrorCode BROTLI_NOINLINE DecodeMetaBlockLength(
+    BrotliDecoderState* s, BrotliBitReader* br) {
+  uint32_t bits;
+  int i;
+  for (;;) {
+    switch (s->substate_metablock_header) {
+      case BROTLI_STATE_METABLOCK_HEADER_NONE:
+        if (!BrotliSafeReadBits(br, 1, &bits)) {
+          return BROTLI_DECODER_NEEDS_MORE_INPUT;
+        }
+        s->is_last_metablock = bits ? 1 : 0;
+        s->meta_block_remaining_len = 0;
+        s->is_uncompressed = 0;
+        s->is_metadata = 0;
+        if (!s->is_last_metablock) {
+          s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NIBBLES;
+          break;
+        }
+        s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_EMPTY;
+      /* Fall through. */
+
+      case BROTLI_STATE_METABLOCK_HEADER_EMPTY:
+        if (!BrotliSafeReadBits(br, 1, &bits)) {
+          return BROTLI_DECODER_NEEDS_MORE_INPUT;
+        }
+        if (bits) {
+          s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE;
+          return BROTLI_DECODER_SUCCESS;
+        }
+        s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NIBBLES;
+      /* Fall through. */
+
+      case BROTLI_STATE_METABLOCK_HEADER_NIBBLES:
+        if (!BrotliSafeReadBits(br, 2, &bits)) {
+          return BROTLI_DECODER_NEEDS_MORE_INPUT;
+        }
+        s->size_nibbles = (uint8_t)(bits + 4);
+        s->loop_counter = 0;
+        if (bits == 3) {
+          s->is_metadata = 1;
+          s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_RESERVED;
+          break;
+        }
+        s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_SIZE;
+      /* Fall through. */
+
+      case BROTLI_STATE_METABLOCK_HEADER_SIZE:
+        i = s->loop_counter;
+        for (; i < (int)s->size_nibbles; ++i) {
+          if (!BrotliSafeReadBits(br, 4, &bits)) {
+            s->loop_counter = i;
+            return BROTLI_DECODER_NEEDS_MORE_INPUT;
+          }
+          if (i + 1 == (int)s->size_nibbles && s->size_nibbles > 4 &&
+              bits == 0) {
+            return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_NIBBLE);
+          }
+          s->meta_block_remaining_len |= (int)(bits << (i * 4));
+        }
+        s->substate_metablock_header =
+            BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED;
+      /* Fall through. */
+
+      case BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED:
+        if (!s->is_last_metablock) {
+          if (!BrotliSafeReadBits(br, 1, &bits)) {
+            return BROTLI_DECODER_NEEDS_MORE_INPUT;
+          }
+          s->is_uncompressed = bits ? 1 : 0;
+        }
+        ++s->meta_block_remaining_len;
+        s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE;
+        return BROTLI_DECODER_SUCCESS;
+
+      case BROTLI_STATE_METABLOCK_HEADER_RESERVED:
+        if (!BrotliSafeReadBits(br, 1, &bits)) {
+          return BROTLI_DECODER_NEEDS_MORE_INPUT;
+        }
+        if (bits != 0) {
+          return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_RESERVED);
+        }
+        s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_BYTES;
+      /* Fall through. */
+
+      case BROTLI_STATE_METABLOCK_HEADER_BYTES:
+        if (!BrotliSafeReadBits(br, 2, &bits)) {
+          return BROTLI_DECODER_NEEDS_MORE_INPUT;
+        }
+        if (bits == 0) {
+          s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE;
+          return BROTLI_DECODER_SUCCESS;
+        }
+        s->size_nibbles = (uint8_t)bits;
+        s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_METADATA;
+      /* Fall through. */
+
+      case BROTLI_STATE_METABLOCK_HEADER_METADATA:
+        i = s->loop_counter;
+        for (; i < (int)s->size_nibbles; ++i) {
+          if (!BrotliSafeReadBits(br, 8, &bits)) {
+            s->loop_counter = i;
+            return BROTLI_DECODER_NEEDS_MORE_INPUT;
+          }
+          if (i + 1 == (int)s->size_nibbles && s->size_nibbles > 1 &&
+              bits == 0) {
+            return BROTLI_FAILURE(
+                BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_META_NIBBLE);
+          }
+          s->meta_block_remaining_len |= (int)(bits << (i * 8));
+        }
+        ++s->meta_block_remaining_len;
+        s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE;
+        return BROTLI_DECODER_SUCCESS;
+
+      default:
+        return
+            BROTLI_FAILURE(BROTLI_DECODER_ERROR_UNREACHABLE);
+    }
+  }
+}
+
+/* Decodes the Huffman code.
+   This method doesn't read data from the bit reader, BUT drops the amount of
+   bits that correspond to the decoded symbol.
+   bits MUST contain at least 15 (BROTLI_HUFFMAN_MAX_CODE_LENGTH) valid bits. */
+static BROTLI_INLINE uint32_t DecodeSymbol(uint32_t bits,
+                                           const HuffmanCode* table,
+                                           BrotliBitReader* br) {
+  BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(table);
+  BROTLI_HC_ADJUST_TABLE_INDEX(table, bits & HUFFMAN_TABLE_MASK);
+  if (BROTLI_HC_FAST_LOAD_BITS(table) > HUFFMAN_TABLE_BITS) {
+    uint32_t nbits = BROTLI_HC_FAST_LOAD_BITS(table) - HUFFMAN_TABLE_BITS;
+    BrotliDropBits(br, HUFFMAN_TABLE_BITS);
+    BROTLI_HC_ADJUST_TABLE_INDEX(table,
+        BROTLI_HC_FAST_LOAD_VALUE(table) +
+        ((bits >> HUFFMAN_TABLE_BITS) & BitMask(nbits)));
+  }
+  BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(table));
+  return BROTLI_HC_FAST_LOAD_VALUE(table);
+}
+
+/* Reads and decodes the next Huffman code from bit-stream.
+   This method peeks 16 bits of input and drops 0 - 15 of them. */
+static BROTLI_INLINE uint32_t ReadSymbol(const HuffmanCode* table,
+                                         BrotliBitReader* br) {
+  return DecodeSymbol(BrotliGet16BitsUnmasked(br), table, br);
+}
+
+/* Same as DecodeSymbol, but it is known that there is less than 15 bits of
+   input are currently available. */
+static BROTLI_NOINLINE BROTLI_BOOL SafeDecodeSymbol(
+    const HuffmanCode* table, BrotliBitReader* br, uint32_t* result) {
+  uint32_t val;
+  uint32_t available_bits = BrotliGetAvailableBits(br);
+  BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(table);
+  if (available_bits == 0) {
+    if (BROTLI_HC_FAST_LOAD_BITS(table) == 0) {
+      *result = BROTLI_HC_FAST_LOAD_VALUE(table);
+      return BROTLI_TRUE;
+    }
+    return BROTLI_FALSE;  /* No valid bits at all. */
+  }
+  val = (uint32_t)BrotliGetBitsUnmasked(br);
+  BROTLI_HC_ADJUST_TABLE_INDEX(table, val & HUFFMAN_TABLE_MASK);
+  if (BROTLI_HC_FAST_LOAD_BITS(table) <= HUFFMAN_TABLE_BITS) {
+    if (BROTLI_HC_FAST_LOAD_BITS(table) <= available_bits) {
+      BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(table));
+      *result = BROTLI_HC_FAST_LOAD_VALUE(table);
+      return BROTLI_TRUE;
+    } else {
+      return BROTLI_FALSE;  /* Not enough bits for the first level. */
+    }
+  }
+  if (available_bits <= HUFFMAN_TABLE_BITS) {
+    return BROTLI_FALSE;  /* Not enough bits to move to the second level. */
+  }
+
+  /* Speculatively drop HUFFMAN_TABLE_BITS. */
+  val = (val & BitMask(BROTLI_HC_FAST_LOAD_BITS(table))) >> HUFFMAN_TABLE_BITS;
+  available_bits -= HUFFMAN_TABLE_BITS;
+  BROTLI_HC_ADJUST_TABLE_INDEX(table, BROTLI_HC_FAST_LOAD_VALUE(table) + val);
+  if (available_bits < BROTLI_HC_FAST_LOAD_BITS(table)) {
+    return BROTLI_FALSE;  /* Not enough bits for the second level. */
+  }
+
+  BrotliDropBits(br, HUFFMAN_TABLE_BITS + BROTLI_HC_FAST_LOAD_BITS(table));
+  *result = BROTLI_HC_FAST_LOAD_VALUE(table);
+  return BROTLI_TRUE;
+}
+
+static BROTLI_INLINE BROTLI_BOOL SafeReadSymbol(
+    const HuffmanCode* table, BrotliBitReader* br, uint32_t* result) {
+  uint32_t val;
+  if (BROTLI_PREDICT_TRUE(BrotliSafeGetBits(br, 15, &val))) {
+    *result = DecodeSymbol(val, table, br);
+    return BROTLI_TRUE;
+  }
+  return SafeDecodeSymbol(table, br, result);
+}
+
+/* Makes a look-up in first level Huffman table. Peeks 8 bits. */
+static BROTLI_INLINE void PreloadSymbol(int safe,
+                                        const HuffmanCode* table,
+                                        BrotliBitReader* br,
+                                        uint32_t* bits,
+                                        uint32_t* value) {
+  if (safe) {
+    return;
+  }
+  BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(table);
+  BROTLI_HC_ADJUST_TABLE_INDEX(table, BrotliGetBits(br, HUFFMAN_TABLE_BITS));
+  *bits = BROTLI_HC_FAST_LOAD_BITS(table);
+  *value = BROTLI_HC_FAST_LOAD_VALUE(table);
+}
+
+/* Decodes the next Huffman code using data prepared by PreloadSymbol.
+   Reads 0 - 15 bits. Also peeks 8 following bits. */
+static BROTLI_INLINE uint32_t ReadPreloadedSymbol(const HuffmanCode* table,
+                                                  BrotliBitReader* br,
+                                                  uint32_t* bits,
+                                                  uint32_t* value) {
+  uint32_t result = *value;
+  if (BROTLI_PREDICT_FALSE(*bits > HUFFMAN_TABLE_BITS)) {
+    uint32_t val = BrotliGet16BitsUnmasked(br);
+    const HuffmanCode* ext = table + (val & HUFFMAN_TABLE_MASK) + *value;
+    uint32_t mask = BitMask((*bits - HUFFMAN_TABLE_BITS));
+    BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(ext);
+    BrotliDropBits(br, HUFFMAN_TABLE_BITS);
+    BROTLI_HC_ADJUST_TABLE_INDEX(ext, (val >> HUFFMAN_TABLE_BITS) & mask);
+    BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(ext));
+    result = BROTLI_HC_FAST_LOAD_VALUE(ext);
+  } else {
+    BrotliDropBits(br, *bits);
+  }
+  PreloadSymbol(0, table, br, bits, value);
+  return result;
+}
+
+static BROTLI_INLINE uint32_t Log2Floor(uint32_t x) {
+  uint32_t result = 0;
+  while (x) {
+    x >>= 1;
+    ++result;
+  }
+  return result;
+}
+
+/* Reads (s->symbol + 1) symbols.
+   Totally 1..4 symbols are read, 1..11 bits each.
+   The list of symbols MUST NOT contain duplicates. */
+static BrotliDecoderErrorCode ReadSimpleHuffmanSymbols(
+    uint32_t alphabet_size_max, uint32_t alphabet_size_limit,
+    BrotliDecoderState* s) {
+  /* max_bits == 1..11; symbol == 0..3; 1..44 bits will be read. */
+  BrotliBitReader* br = &s->br;
+  BrotliMetablockHeaderArena* h = &s->arena.header;
+  uint32_t max_bits = Log2Floor(alphabet_size_max - 1);
+  uint32_t i = h->sub_loop_counter;
+  uint32_t num_symbols = h->symbol;
+  while (i <= num_symbols) {
+    uint32_t v;
+    if (BROTLI_PREDICT_FALSE(!BrotliSafeReadBits(br, max_bits, &v))) {
+      h->sub_loop_counter = i;
+      h->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_READ;
+      return BROTLI_DECODER_NEEDS_MORE_INPUT;
+    }
+    if (v >= alphabet_size_limit) {
+      return
+          BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_ALPHABET);
+    }
+    h->symbols_lists_array[i] = (uint16_t)v;
+    BROTLI_LOG_UINT(h->symbols_lists_array[i]);
+    ++i;
+  }
+
+  for (i = 0; i < num_symbols; ++i) {
+    uint32_t k = i + 1;
+    for (; k <= num_symbols; ++k) {
+      if (h->symbols_lists_array[i] == h->symbols_lists_array[k]) {
+        return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_SAME);
+      }
+    }
+  }
+
+  return BROTLI_DECODER_SUCCESS;
+}
+
+/* Process single decoded symbol code length:
+    A) reset the repeat variable
+    B) remember code length (if it is not 0)
+    C) extend corresponding index-chain
+    D) reduce the Huffman space
+    E) update the histogram */
+static BROTLI_INLINE void ProcessSingleCodeLength(uint32_t code_len,
+    uint32_t* symbol, uint32_t* repeat, uint32_t* space,
+    uint32_t* prev_code_len, uint16_t* symbol_lists,
+    uint16_t* code_length_histo, int* next_symbol) {
+  *repeat = 0;
+  if (code_len != 0) {  /* code_len == 1..15 */
+    symbol_lists[next_symbol[code_len]] = (uint16_t)(*symbol);
+    next_symbol[code_len] = (int)(*symbol);
+    *prev_code_len = code_len;
+    *space -= 32768U >> code_len;
+    code_length_histo[code_len]++;
+    BROTLI_LOG(("[ReadHuffmanCode] code_length[%d] = %d\n",
+        (int)*symbol, (int)code_len));
+  }
+  (*symbol)++;
+}
+
+/* Process repeated symbol code length.
+    A) Check if it is the extension of previous repeat sequence; if the decoded
+       value is not BROTLI_REPEAT_PREVIOUS_CODE_LENGTH, then it is a new
+       symbol-skip
+    B) Update repeat variable
+    C) Check if operation is feasible (fits alphabet)
+    D) For each symbol do the same operations as in ProcessSingleCodeLength
+
+   PRECONDITION: code_len == BROTLI_REPEAT_PREVIOUS_CODE_LENGTH or
+                 code_len == BROTLI_REPEAT_ZERO_CODE_LENGTH */
+static BROTLI_INLINE void ProcessRepeatedCodeLength(uint32_t code_len,
+    uint32_t repeat_delta, uint32_t alphabet_size, uint32_t* symbol,
+    uint32_t* repeat, uint32_t* space, uint32_t* prev_code_len,
+    uint32_t* repeat_code_len, uint16_t* symbol_lists,
+    uint16_t* code_length_histo, int* next_symbol) {
+  uint32_t old_repeat;
+  uint32_t extra_bits = 3;  /* for BROTLI_REPEAT_ZERO_CODE_LENGTH */
+  uint32_t new_len = 0;  /* for BROTLI_REPEAT_ZERO_CODE_LENGTH */
+  if (code_len == BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) {
+    new_len = *prev_code_len;
+    extra_bits = 2;
+  }
+  if (*repeat_code_len != new_len) {
+    *repeat = 0;
+    *repeat_code_len = new_len;
+  }
+  old_repeat = *repeat;
+  if (*repeat > 0) {
+    *repeat -= 2;
+    *repeat <<= extra_bits;
+  }
+  *repeat += repeat_delta + 3U;
+  repeat_delta = *repeat - old_repeat;
+  if (*symbol + repeat_delta > alphabet_size) {
+    BROTLI_DUMP();
+    *symbol = alphabet_size;
+    *space = 0xFFFFF;
+    return;
+  }
+  BROTLI_LOG(("[ReadHuffmanCode] code_length[%d..%d] = %d\n",
+      (int)*symbol, (int)(*symbol + repeat_delta - 1), (int)*repeat_code_len));
+  if (*repeat_code_len != 0) {
+    unsigned last = *symbol + repeat_delta;
+    int next = next_symbol[*repeat_code_len];
+    do {
+      symbol_lists[next] = (uint16_t)*symbol;
+      next = (int)*symbol;
+    } while (++(*symbol) != last);
+    next_symbol[*repeat_code_len] = next;
+    *space -= repeat_delta << (15 - *repeat_code_len);
+    code_length_histo[*repeat_code_len] =
+        (uint16_t)(code_length_histo[*repeat_code_len] + repeat_delta);
+  } else {
+    *symbol += repeat_delta;
+  }
+}
+
+/* Reads and decodes symbol codelengths. */
+static BrotliDecoderErrorCode ReadSymbolCodeLengths(
+    uint32_t alphabet_size, BrotliDecoderState* s) {
+  BrotliBitReader* br = &s->br;
+  BrotliMetablockHeaderArena* h = &s->arena.header;
+  uint32_t symbol = h->symbol;
+  uint32_t repeat = h->repeat;
+  uint32_t space = h->space;
+  uint32_t prev_code_len = h->prev_code_len;
+  uint32_t repeat_code_len = h->repeat_code_len;
+  uint16_t* symbol_lists = h->symbol_lists;
+  uint16_t* code_length_histo = h->code_length_histo;
+  int* next_symbol = h->next_symbol;
+  if (!BrotliWarmupBitReader(br)) {
+    return BROTLI_DECODER_NEEDS_MORE_INPUT;
+  }
+  while (symbol < alphabet_size && space > 0) {
+    const HuffmanCode* p = h->table;
+    uint32_t code_len;
+    BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(p);
+    if (!BrotliCheckInputAmount(br, BROTLI_SHORT_FILL_BIT_WINDOW_READ)) {
+      h->symbol = symbol;
+      h->repeat = repeat;
+      h->prev_code_len = prev_code_len;
+      h->repeat_code_len = repeat_code_len;
+      h->space = space;
+      return BROTLI_DECODER_NEEDS_MORE_INPUT;
+    }
+    BrotliFillBitWindow16(br);
+    BROTLI_HC_ADJUST_TABLE_INDEX(p, BrotliGetBitsUnmasked(br) &
+        BitMask(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH));
+    BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(p));  /* Use 1..5 bits. */
+    code_len = BROTLI_HC_FAST_LOAD_VALUE(p);  /* code_len == 0..17 */
+    if (code_len < BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) {
+      ProcessSingleCodeLength(code_len, &symbol, &repeat, &space,
+          &prev_code_len, symbol_lists, code_length_histo, next_symbol);
+    } else {  /* code_len == 16..17, extra_bits == 2..3 */
+      uint32_t extra_bits =
+          (code_len == BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) ? 2 : 3;
+      uint32_t repeat_delta =
+          (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(extra_bits);
+      BrotliDropBits(br, extra_bits);
+      ProcessRepeatedCodeLength(code_len, repeat_delta, alphabet_size,
+          &symbol, &repeat, &space, &prev_code_len, &repeat_code_len,
+          symbol_lists, code_length_histo, next_symbol);
+    }
+  }
+  h->space = space;
+  return BROTLI_DECODER_SUCCESS;
+}
+
+static BrotliDecoderErrorCode SafeReadSymbolCodeLengths(
+    uint32_t alphabet_size, BrotliDecoderState* s) {
+  BrotliBitReader* br = &s->br;
+  BrotliMetablockHeaderArena* h = &s->arena.header;
+  BROTLI_BOOL get_byte = BROTLI_FALSE;
+  while (h->symbol < alphabet_size && h->space > 0) {
+    const HuffmanCode* p = h->table;
+    uint32_t code_len;
+    uint32_t available_bits;
+    uint32_t bits = 0;
+    BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(p);
+    if (get_byte && !BrotliPullByte(br)) return BROTLI_DECODER_NEEDS_MORE_INPUT;
+    get_byte = BROTLI_FALSE;
+    available_bits = BrotliGetAvailableBits(br);
+    if (available_bits != 0) {
+      bits = (uint32_t)BrotliGetBitsUnmasked(br);
+    }
+    BROTLI_HC_ADJUST_TABLE_INDEX(p,
+        bits & BitMask(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH));
+    if (BROTLI_HC_FAST_LOAD_BITS(p) > available_bits) {
+      get_byte = BROTLI_TRUE;
+      continue;
+    }
+    code_len = BROTLI_HC_FAST_LOAD_VALUE(p);  /* code_len == 0..17 */
+    if (code_len < BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) {
+      BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(p));
+      ProcessSingleCodeLength(code_len, &h->symbol, &h->repeat, &h->space,
+          &h->prev_code_len, h->symbol_lists, h->code_length_histo,
+          h->next_symbol);
+    } else {  /* code_len == 16..17, extra_bits == 2..3 */
+      uint32_t extra_bits = code_len - 14U;
+      uint32_t repeat_delta = (bits >> BROTLI_HC_FAST_LOAD_BITS(p)) &
+          BitMask(extra_bits);
+      if (available_bits < BROTLI_HC_FAST_LOAD_BITS(p) + extra_bits) {
+        get_byte = BROTLI_TRUE;
+        continue;
+      }
+      BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(p) + extra_bits);
+      ProcessRepeatedCodeLength(code_len, repeat_delta, alphabet_size,
+          &h->symbol, &h->repeat, &h->space, &h->prev_code_len,
+          &h->repeat_code_len, h->symbol_lists, h->code_length_histo,
+          h->next_symbol);
+    }
+  }
+  return BROTLI_DECODER_SUCCESS;
+}
+
+/* Reads and decodes 15..18 codes using static prefix code.
+   Each code is 2..4 bits long. In total 30..72 bits are used. */
+static BrotliDecoderErrorCode ReadCodeLengthCodeLengths(BrotliDecoderState* s) {
+  BrotliBitReader* br = &s->br;
+  BrotliMetablockHeaderArena* h = &s->arena.header;
+  uint32_t num_codes = h->repeat;
+  unsigned space = h->space;
+  uint32_t i = h->sub_loop_counter;
+  for (; i < BROTLI_CODE_LENGTH_CODES; ++i) {
+    const uint8_t code_len_idx = kCodeLengthCodeOrder[i];
+    uint32_t ix;
+    uint32_t v;
+    if (BROTLI_PREDICT_FALSE(!BrotliSafeGetBits(br, 4, &ix))) {
+      uint32_t available_bits = BrotliGetAvailableBits(br);
+      if (available_bits != 0) {
+        ix = BrotliGetBitsUnmasked(br) & 0xF;
+      } else {
+        ix = 0;
+      }
+      if (kCodeLengthPrefixLength[ix] > available_bits) {
+        h->sub_loop_counter = i;
+        h->repeat = num_codes;
+        h->space = space;
+        h->substate_huffman = BROTLI_STATE_HUFFMAN_COMPLEX;
+        return BROTLI_DECODER_NEEDS_MORE_INPUT;
+      }
+    }
+    v = kCodeLengthPrefixValue[ix];
+    BrotliDropBits(br, kCodeLengthPrefixLength[ix]);
+    h->code_length_code_lengths[code_len_idx] = (uint8_t)v;
+    BROTLI_LOG_ARRAY_INDEX(h->code_length_code_lengths, code_len_idx);
+    if (v != 0) {
+      space = space - (32U >> v);
+      ++num_codes;
+      ++h->code_length_histo[v];
+      if (space - 1U >= 32U) {
+        /* space is 0 or wrapped around. */
+        break;
+      }
+    }
+  }
+  if (!(num_codes == 1 || space == 0)) {
+    return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_CL_SPACE);
+  }
+  return BROTLI_DECODER_SUCCESS;
+}
+
+/* Decodes the Huffman tables.
+   There are 2 scenarios:
+    A) Huffman code contains only few symbols (1..4). Those symbols are read
+       directly; their code lengths are defined by the number of symbols.
+       For this scenario 4 - 49 bits will be read.
+
+    B) 2-phase decoding:
+    B.1) Small Huffman table is decoded; it is specified with code lengths
+         encoded with predefined entropy code. 32 - 74 bits are used.
+    B.2) Decoded table is used to decode code lengths of symbols in resulting
+         Huffman table. In worst case 3520 bits are read. */
+static BrotliDecoderErrorCode ReadHuffmanCode(uint32_t alphabet_size_max,
+                                              uint32_t alphabet_size_limit,
+                                              HuffmanCode* table,
+                                              uint32_t* opt_table_size,
+                                              BrotliDecoderState* s) {
+  BrotliBitReader* br = &s->br;
+  BrotliMetablockHeaderArena* h = &s->arena.header;
+  /* State machine. */
+  for (;;) {
+    switch (h->substate_huffman) {
+      case BROTLI_STATE_HUFFMAN_NONE:
+        if (!BrotliSafeReadBits(br, 2, &h->sub_loop_counter)) {
+          return BROTLI_DECODER_NEEDS_MORE_INPUT;
+        }
+        BROTLI_LOG_UINT(h->sub_loop_counter);
+        /* The value is used as follows:
+           1 for simple code;
+           0 for no skipping, 2 skips 2 code lengths, 3 skips 3 code lengths */
+        if (h->sub_loop_counter != 1) {
+          h->space = 32;
+          h->repeat = 0;  /* num_codes */
+          memset(&h->code_length_histo[0], 0, sizeof(h->code_length_histo[0]) *
+              (BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH + 1));
+          memset(&h->code_length_code_lengths[0], 0,
+              sizeof(h->code_length_code_lengths));
+          h->substate_huffman = BROTLI_STATE_HUFFMAN_COMPLEX;
+          continue;
+        }
+      /* Fall through. */
+
+      case BROTLI_STATE_HUFFMAN_SIMPLE_SIZE:
+        /* Read symbols, codes & code lengths directly. */
+        if (!BrotliSafeReadBits(br, 2, &h->symbol)) {  /* num_symbols */
+          h->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_SIZE;
+          return BROTLI_DECODER_NEEDS_MORE_INPUT;
+        }
+        h->sub_loop_counter = 0;
+      /* Fall through. */
+
+      case BROTLI_STATE_HUFFMAN_SIMPLE_READ: {
+        BrotliDecoderErrorCode result =
+            ReadSimpleHuffmanSymbols(alphabet_size_max, alphabet_size_limit, s);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          return result;
+        }
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_HUFFMAN_SIMPLE_BUILD: {
+        uint32_t table_size;
+        if (h->symbol == 3) {
+          uint32_t bits;
+          if (!BrotliSafeReadBits(br, 1, &bits)) {
+            h->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_BUILD;
+            return BROTLI_DECODER_NEEDS_MORE_INPUT;
+          }
+          h->symbol += bits;
+        }
+        BROTLI_LOG_UINT(h->symbol);
+        table_size = BrotliBuildSimpleHuffmanTable(
+            table, HUFFMAN_TABLE_BITS, h->symbols_lists_array, h->symbol);
+        if (opt_table_size) {
+          *opt_table_size = table_size;
+        }
+        h->substate_huffman = BROTLI_STATE_HUFFMAN_NONE;
+        return BROTLI_DECODER_SUCCESS;
+      }
+
+      /* Decode Huffman-coded code lengths. */
+      case BROTLI_STATE_HUFFMAN_COMPLEX: {
+        uint32_t i;
+        BrotliDecoderErrorCode result = ReadCodeLengthCodeLengths(s);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          return result;
+        }
+        BrotliBuildCodeLengthsHuffmanTable(h->table,
+                                           h->code_length_code_lengths,
+                                           h->code_length_histo);
+        memset(&h->code_length_histo[0], 0, sizeof(h->code_length_histo));
+        for (i = 0; i <= BROTLI_HUFFMAN_MAX_CODE_LENGTH; ++i) {
+          h->next_symbol[i] = (int)i - (BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1);
+          h->symbol_lists[h->next_symbol[i]] = 0xFFFF;
+        }
+
+        h->symbol = 0;
+        h->prev_code_len = BROTLI_INITIAL_REPEATED_CODE_LENGTH;
+        h->repeat = 0;
+        h->repeat_code_len = 0;
+        h->space = 32768;
+        h->substate_huffman = BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS;
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS: {
+        uint32_t table_size;
+        BrotliDecoderErrorCode result = ReadSymbolCodeLengths(
+            alphabet_size_limit, s);
+        if (result == BROTLI_DECODER_NEEDS_MORE_INPUT) {
+          result = SafeReadSymbolCodeLengths(alphabet_size_limit, s);
+        }
+        if (result != BROTLI_DECODER_SUCCESS) {
+          return result;
+        }
+
+        if (h->space != 0) {
+          BROTLI_LOG(("[ReadHuffmanCode] space = %d\n", (int)h->space));
+          return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_HUFFMAN_SPACE);
+        }
+        table_size = BrotliBuildHuffmanTable(
+            table, HUFFMAN_TABLE_BITS, h->symbol_lists, h->code_length_histo);
+        if (opt_table_size) {
+          *opt_table_size = table_size;
+        }
+        h->substate_huffman = BROTLI_STATE_HUFFMAN_NONE;
+        return BROTLI_DECODER_SUCCESS;
+      }
+
+      default:
+        return
+            BROTLI_FAILURE(BROTLI_DECODER_ERROR_UNREACHABLE);
+    }
+  }
+}
+
+/* Decodes a block length by reading 3..39 bits. */
+static BROTLI_INLINE uint32_t ReadBlockLength(const HuffmanCode* table,
+                                              BrotliBitReader* br) {
+  uint32_t code;
+  uint32_t nbits;
+  code = ReadSymbol(table, br);
+  nbits = _kBrotliPrefixCodeRanges[code].nbits;  /* nbits == 2..24 */
+  return _kBrotliPrefixCodeRanges[code].offset + BrotliReadBits24(br, nbits);
+}
+
+/* WARNING: if state is not BROTLI_STATE_READ_BLOCK_LENGTH_NONE, then
+   reading can't be continued with ReadBlockLength. */
+static BROTLI_INLINE BROTLI_BOOL SafeReadBlockLength(
+    BrotliDecoderState* s, uint32_t* result, const HuffmanCode* table,
+    BrotliBitReader* br) {
+  uint32_t index;
+  if (s->substate_read_block_length == BROTLI_STATE_READ_BLOCK_LENGTH_NONE) {
+    if (!SafeReadSymbol(table, br, &index)) {
+      return BROTLI_FALSE;
+    }
+  } else {
+    index = s->block_length_index;
+  }
+  {
+    uint32_t bits;
+    uint32_t nbits = _kBrotliPrefixCodeRanges[index].nbits;
+    uint32_t offset = _kBrotliPrefixCodeRanges[index].offset;
+    if (!BrotliSafeReadBits(br, nbits, &bits)) {
+      s->block_length_index = index;
+      s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_SUFFIX;
+      return BROTLI_FALSE;
+    }
+    *result = offset + bits;
+    s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE;
+    return BROTLI_TRUE;
+  }
+}
+
+/* Transform:
+    1) initialize list L with values 0, 1,... 255
+    2) For each input element X:
+    2.1) let Y = L[X]
+    2.2) remove X-th element from L
+    2.3) prepend Y to L
+    2.4) append Y to output
+
+   In most cases max(Y) <= 7, so most of L remains intact.
+   To reduce the cost of initialization, we reuse L, remember the upper bound
+   of Y values, and reinitialize only first elements in L.
+
+   Most of input values are 0 and 1. To reduce number of branches, we replace
+   inner for loop with do-while. */
+static BROTLI_NOINLINE void InverseMoveToFrontTransform(
+    uint8_t* v, uint32_t v_len, BrotliDecoderState* state) {
+  /* Reinitialize elements that could have been changed. */
+  uint32_t i = 1;
+  uint32_t upper_bound = state->mtf_upper_bound;
+  uint32_t* mtf = &state->mtf[1];  /* Make mtf[-1] addressable. */
+  uint8_t* mtf_u8 = (uint8_t*)mtf;
+  /* Load endian-aware constant. */
+  const uint8_t b0123[4] = {0, 1, 2, 3};
+  uint32_t pattern;
+  memcpy(&pattern, &b0123, 4);
+
+  /* Initialize list using 4 consequent values pattern. */
+  mtf[0] = pattern;
+  do {
+    pattern += 0x04040404;  /* Advance all 4 values by 4. */
+    mtf[i] = pattern;
+    i++;
+  } while (i <= upper_bound);
+
+  /* Transform the input. */
+  upper_bound = 0;
+  for (i = 0; i < v_len; ++i) {
+    int index = v[i];
+    uint8_t value = mtf_u8[index];
+    upper_bound |= v[i];
+    v[i] = value;
+    mtf_u8[-1] = value;
+    do {
+      index--;
+      mtf_u8[index + 1] = mtf_u8[index];
+    } while (index >= 0);
+  }
+  /* Remember amount of elements to be reinitialized. */
+  state->mtf_upper_bound = upper_bound >> 2;
+}
+
+/* Decodes a series of Huffman table using ReadHuffmanCode function. */
+static BrotliDecoderErrorCode HuffmanTreeGroupDecode(
+    HuffmanTreeGroup* group, BrotliDecoderState* s) {
+  BrotliMetablockHeaderArena* h = &s->arena.header;
+  if (h->substate_tree_group != BROTLI_STATE_TREE_GROUP_LOOP) {
+    h->next = group->codes;
+    h->htree_index = 0;
+    h->substate_tree_group = BROTLI_STATE_TREE_GROUP_LOOP;
+  }
+  while (h->htree_index < group->num_htrees) {
+    uint32_t table_size;
+    BrotliDecoderErrorCode result = ReadHuffmanCode(group->alphabet_size_max,
+        group->alphabet_size_limit, h->next, &table_size, s);
+    if (result != BROTLI_DECODER_SUCCESS) return result;
+    group->htrees[h->htree_index] = h->next;
+    h->next += table_size;
+    ++h->htree_index;
+  }
+  h->substate_tree_group = BROTLI_STATE_TREE_GROUP_NONE;
+  return BROTLI_DECODER_SUCCESS;
+}
+
+/* Decodes a context map.
+   Decoding is done in 4 phases:
+    1) Read auxiliary information (6..16 bits) and allocate memory.
+       In case of trivial context map, decoding is finished at this phase.
+    2) Decode Huffman table using ReadHuffmanCode function.
+       This table will be used for reading context map items.
+    3) Read context map items; "0" values could be run-length encoded.
+    4) Optionally, apply InverseMoveToFront transform to the resulting map. */
+static BrotliDecoderErrorCode DecodeContextMap(uint32_t context_map_size,
+                                               uint32_t* num_htrees,
+                                               uint8_t** context_map_arg,
+                                               BrotliDecoderState* s) {
+  BrotliBitReader* br = &s->br;
+  BrotliDecoderErrorCode result = BROTLI_DECODER_SUCCESS;
+  BrotliMetablockHeaderArena* h = &s->arena.header;
+
+  switch ((int)h->substate_context_map) {
+    case BROTLI_STATE_CONTEXT_MAP_NONE:
+      result = DecodeVarLenUint8(s, br, num_htrees);
+      if (result != BROTLI_DECODER_SUCCESS) {
+        return result;
+      }
+      (*num_htrees)++;
+      h->context_index = 0;
+      BROTLI_LOG_UINT(context_map_size);
+      BROTLI_LOG_UINT(*num_htrees);
+      *context_map_arg =
+          (uint8_t*)BROTLI_DECODER_ALLOC(s, (size_t)context_map_size);
+      if (*context_map_arg == 0) {
+        return BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MAP);
+      }
+      if (*num_htrees <= 1) {
+        memset(*context_map_arg, 0, (size_t)context_map_size);
+        return BROTLI_DECODER_SUCCESS;
+      }
+      h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_READ_PREFIX;
+    /* Fall through. */
+
+    case BROTLI_STATE_CONTEXT_MAP_READ_PREFIX: {
+      uint32_t bits;
+      /* In next stage ReadHuffmanCode uses at least 4 bits, so it is safe
+         to peek 4 bits ahead. */
+      if (!BrotliSafeGetBits(br, 5, &bits)) {
+        return BROTLI_DECODER_NEEDS_MORE_INPUT;
+      }
+      if ((bits & 1) != 0) { /* Use RLE for zeros. */
+        h->max_run_length_prefix = (bits >> 1) + 1;
+        BrotliDropBits(br, 5);
+      } else {
+        h->max_run_length_prefix = 0;
+        BrotliDropBits(br, 1);
+      }
+      BROTLI_LOG_UINT(h->max_run_length_prefix);
+      h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_HUFFMAN;
+    }
+    /* Fall through. */
+
+    case BROTLI_STATE_CONTEXT_MAP_HUFFMAN: {
+      uint32_t alphabet_size = *num_htrees + h->max_run_length_prefix;
+      result = ReadHuffmanCode(alphabet_size, alphabet_size,
+                               h->context_map_table, NULL, s);
+      if (result != BROTLI_DECODER_SUCCESS) return result;
+      h->code = 0xFFFF;
+      h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_DECODE;
+    }
+    /* Fall through. */
+
+    case BROTLI_STATE_CONTEXT_MAP_DECODE: {
+      uint32_t context_index = h->context_index;
+      uint32_t max_run_length_prefix = h->max_run_length_prefix;
+      uint8_t* context_map = *context_map_arg;
+      uint32_t code = h->code;
+      BROTLI_BOOL skip_preamble = (code != 0xFFFF);
+      while (context_index < context_map_size || skip_preamble) {
+        if (!skip_preamble) {
+          if (!SafeReadSymbol(h->context_map_table, br, &code)) {
+            h->code = 0xFFFF;
+            h->context_index = context_index;
+            return BROTLI_DECODER_NEEDS_MORE_INPUT;
+          }
+          BROTLI_LOG_UINT(code);
+
+          if (code == 0) {
+            context_map[context_index++] = 0;
+            continue;
+          }
+          if (code > max_run_length_prefix) {
+            context_map[context_index++] =
+                (uint8_t)(code - max_run_length_prefix);
+            continue;
+          }
+        } else {
+          skip_preamble = BROTLI_FALSE;
+        }
+        /* RLE sub-stage. */
+        {
+          uint32_t reps;
+          if (!BrotliSafeReadBits(br, code, &reps)) {
+            h->code = code;
+            h->context_index = context_index;
+            return BROTLI_DECODER_NEEDS_MORE_INPUT;
+          }
+          reps += 1U << code;
+          BROTLI_LOG_UINT(reps);
+          if (context_index + reps > context_map_size) {
+            return
+                BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_CONTEXT_MAP_REPEAT);
+          }
+          do {
+            context_map[context_index++] = 0;
+          } while (--reps);
+        }
+      }
+    }
+    /* Fall through. */
+
+    case BROTLI_STATE_CONTEXT_MAP_TRANSFORM: {
+      uint32_t bits;
+      if (!BrotliSafeReadBits(br, 1, &bits)) {
+        h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_TRANSFORM;
+        return BROTLI_DECODER_NEEDS_MORE_INPUT;
+      }
+      if (bits != 0) {
+        InverseMoveToFrontTransform(*context_map_arg, context_map_size, s);
+      }
+      h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_NONE;
+      return BROTLI_DECODER_SUCCESS;
+    }
+
+    default:
+      return
+          BROTLI_FAILURE(BROTLI_DECODER_ERROR_UNREACHABLE);
+  }
+}
+
+/* Decodes a command or literal and updates block type ring-buffer.
+   Reads 3..54 bits. */
+static BROTLI_INLINE BROTLI_BOOL DecodeBlockTypeAndLength(
+    int safe, BrotliDecoderState* s, int tree_type) {
+  uint32_t max_block_type = s->num_block_types[tree_type];
+  const HuffmanCode* type_tree = &s->block_type_trees[
+      tree_type * BROTLI_HUFFMAN_MAX_SIZE_258];
+  const HuffmanCode* len_tree = &s->block_len_trees[
+      tree_type * BROTLI_HUFFMAN_MAX_SIZE_26];
+  BrotliBitReader* br = &s->br;
+  uint32_t* ringbuffer = &s->block_type_rb[tree_type * 2];
+  uint32_t block_type;
+  if (max_block_type <= 1) {
+    return BROTLI_FALSE;
+  }
+
+  /* Read 0..15 + 3..39 bits. */
+  if (!safe) {
+    block_type = ReadSymbol(type_tree, br);
+    s->block_length[tree_type] = ReadBlockLength(len_tree, br);
+  } else {
+    BrotliBitReaderState memento;
+    BrotliBitReaderSaveState(br, &memento);
+    if (!SafeReadSymbol(type_tree, br, &block_type)) return BROTLI_FALSE;
+    if (!SafeReadBlockLength(s, &s->block_length[tree_type], len_tree, br)) {
+      s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE;
+      BrotliBitReaderRestoreState(br, &memento);
+      return BROTLI_FALSE;
+    }
+  }
+
+  if (block_type == 1) {
+    block_type = ringbuffer[1] + 1;
+  } else if (block_type == 0) {
+    block_type = ringbuffer[0];
+  } else {
+    block_type -= 2;
+  }
+  if (block_type >= max_block_type) {
+    block_type -= max_block_type;
+  }
+  ringbuffer[0] = ringbuffer[1];
+  ringbuffer[1] = block_type;
+  return BROTLI_TRUE;
+}
+
+static BROTLI_INLINE void DetectTrivialLiteralBlockTypes(
+    BrotliDecoderState* s) {
+  size_t i;
+  for (i = 0; i < 8; ++i) s->trivial_literal_contexts[i] = 0;
+  for (i = 0; i < s->num_block_types[0]; i++) {
+    size_t offset = i << BROTLI_LITERAL_CONTEXT_BITS;
+    size_t error = 0;
+    size_t sample = s->context_map[offset];
+    size_t j;
+    for (j = 0; j < (1u << BROTLI_LITERAL_CONTEXT_BITS);) {
+      BROTLI_REPEAT(4, error |= s->context_map[offset + j++] ^ sample;)
+    }
+    if (error == 0) {
+      s->trivial_literal_contexts[i >> 5] |= 1u << (i & 31);
+    }
+  }
+}
+
+static BROTLI_INLINE void PrepareLiteralDecoding(BrotliDecoderState* s) {
+  uint8_t context_mode;
+  size_t trivial;
+  uint32_t block_type = s->block_type_rb[1];
+  uint32_t context_offset = block_type << BROTLI_LITERAL_CONTEXT_BITS;
+  s->context_map_slice = s->context_map + context_offset;
+  trivial = s->trivial_literal_contexts[block_type >> 5];
+  s->trivial_literal_context = (trivial >> (block_type & 31)) & 1;
+  s->literal_htree = s->literal_hgroup.htrees[s->context_map_slice[0]];
+  context_mode = s->context_modes[block_type] & 3;
+  s->context_lookup = BROTLI_CONTEXT_LUT(context_mode);
+}
+
+/* Decodes the block type and updates the state for literal context.
+   Reads 3..54 bits. */
+static BROTLI_INLINE BROTLI_BOOL DecodeLiteralBlockSwitchInternal(
+    int safe, BrotliDecoderState* s) {
+  if (!DecodeBlockTypeAndLength(safe, s, 0)) {
+    return BROTLI_FALSE;
+  }
+  PrepareLiteralDecoding(s);
+  return BROTLI_TRUE;
+}
+
+static void BROTLI_NOINLINE DecodeLiteralBlockSwitch(BrotliDecoderState* s) {
+  DecodeLiteralBlockSwitchInternal(0, s);
+}
+
+static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeLiteralBlockSwitch(
+    BrotliDecoderState* s) {
+  return DecodeLiteralBlockSwitchInternal(1, s);
+}
+
+/* Block switch for insert/copy length.
+   Reads 3..54 bits. */
+static BROTLI_INLINE BROTLI_BOOL DecodeCommandBlockSwitchInternal(
+    int safe, BrotliDecoderState* s) {
+  if (!DecodeBlockTypeAndLength(safe, s, 1)) {
+    return BROTLI_FALSE;
+  }
+  s->htree_command = s->insert_copy_hgroup.htrees[s->block_type_rb[3]];
+  return BROTLI_TRUE;
+}
+
+static void BROTLI_NOINLINE DecodeCommandBlockSwitch(BrotliDecoderState* s) {
+  DecodeCommandBlockSwitchInternal(0, s);
+}
+
+static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeCommandBlockSwitch(
+    BrotliDecoderState* s) {
+  return DecodeCommandBlockSwitchInternal(1, s);
+}
+
+/* Block switch for distance codes.
+   Reads 3..54 bits. */
+static BROTLI_INLINE BROTLI_BOOL DecodeDistanceBlockSwitchInternal(
+    int safe, BrotliDecoderState* s) {
+  if (!DecodeBlockTypeAndLength(safe, s, 2)) {
+    return BROTLI_FALSE;
+  }
+  s->dist_context_map_slice = s->dist_context_map +
+      (s->block_type_rb[5] << BROTLI_DISTANCE_CONTEXT_BITS);
+  s->dist_htree_index = s->dist_context_map_slice[s->distance_context];
+  return BROTLI_TRUE;
+}
+
+static void BROTLI_NOINLINE DecodeDistanceBlockSwitch(BrotliDecoderState* s) {
+  DecodeDistanceBlockSwitchInternal(0, s);
+}
+
+static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeDistanceBlockSwitch(
+    BrotliDecoderState* s) {
+  return DecodeDistanceBlockSwitchInternal(1, s);
+}
+
+static size_t UnwrittenBytes(const BrotliDecoderState* s, BROTLI_BOOL wrap) {
+  size_t pos = wrap && s->pos > s->ringbuffer_size ?
+      (size_t)s->ringbuffer_size : (size_t)(s->pos);
+  size_t partial_pos_rb = (s->rb_roundtrips * (size_t)s->ringbuffer_size) + pos;
+  return partial_pos_rb - s->partial_pos_out;
+}
+
+/* Dumps output.
+   Returns BROTLI_DECODER_NEEDS_MORE_OUTPUT only if there is more output to push
+   and either ring-buffer is as big as window size, or |force| is true. */
+static BrotliDecoderErrorCode BROTLI_NOINLINE WriteRingBuffer(
+    BrotliDecoderState* s, size_t* available_out, uint8_t** next_out,
+    size_t* total_out, BROTLI_BOOL force) {
+  uint8_t* start =
+      s->ringbuffer + (s->partial_pos_out & (size_t)s->ringbuffer_mask);
+  size_t to_write = UnwrittenBytes(s, BROTLI_TRUE);
+  size_t num_written = *available_out;
+  if (num_written > to_write) {
+    num_written = to_write;
+  }
+  if (s->meta_block_remaining_len < 0) {
+    return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_1);
+  }
+  if (next_out && !*next_out) {
+    *next_out = start;
+  } else {
+    if (next_out) {
+      memcpy(*next_out, start, num_written);
+      *next_out += num_written;
+    }
+  }
+  *available_out -= num_written;
+  BROTLI_LOG_UINT(to_write);
+  BROTLI_LOG_UINT(num_written);
+  s->partial_pos_out += num_written;
+  if (total_out) {
+    *total_out = s->partial_pos_out;
+  }
+  if (num_written < to_write) {
+    if (s->ringbuffer_size == (1 << s->window_bits) || force) {
+      return BROTLI_DECODER_NEEDS_MORE_OUTPUT;
+    } else {
+      return BROTLI_DECODER_SUCCESS;
+    }
+  }
+  /* Wrap ring buffer only if it has reached its maximal size. */
+  if (s->ringbuffer_size == (1 << s->window_bits) &&
+      s->pos >= s->ringbuffer_size) {
+    s->pos -= s->ringbuffer_size;
+    s->rb_roundtrips++;
+    s->should_wrap_ringbuffer = (size_t)s->pos != 0 ? 1 : 0;
+  }
+  return BROTLI_DECODER_SUCCESS;
+}
+
+static void BROTLI_NOINLINE WrapRingBuffer(BrotliDecoderState* s) {
+  if (s->should_wrap_ringbuffer) {
+    memcpy(s->ringbuffer, s->ringbuffer_end, (size_t)s->pos);
+    s->should_wrap_ringbuffer = 0;
+  }
+}
+
+/* Allocates ring-buffer.
+
+   s->ringbuffer_size MUST be updated by BrotliCalculateRingBufferSize before
+   this function is called.
+
+   Last two bytes of ring-buffer are initialized to 0, so context calculation
+   could be done uniformly for the first two and all other positions. */
+static BROTLI_BOOL BROTLI_NOINLINE BrotliEnsureRingBuffer(
+    BrotliDecoderState* s) {
+  uint8_t* old_ringbuffer = s->ringbuffer;
+  if (s->ringbuffer_size == s->new_ringbuffer_size) {
+    return BROTLI_TRUE;
+  }
+
+  s->ringbuffer = (uint8_t*)BROTLI_DECODER_ALLOC(s,
+      (size_t)(s->new_ringbuffer_size) + kRingBufferWriteAheadSlack);
+  if (s->ringbuffer == 0) {
+    /* Restore previous value. */
+    s->ringbuffer = old_ringbuffer;
+    return BROTLI_FALSE;
+  }
+  s->ringbuffer[s->new_ringbuffer_size - 2] = 0;
+  s->ringbuffer[s->new_ringbuffer_size - 1] = 0;
+
+  if (!!old_ringbuffer) {
+    memcpy(s->ringbuffer, old_ringbuffer, (size_t)s->pos);
+    BROTLI_DECODER_FREE(s, old_ringbuffer);
+  }
+
+  s->ringbuffer_size = s->new_ringbuffer_size;
+  s->ringbuffer_mask = s->new_ringbuffer_size - 1;
+  s->ringbuffer_end = s->ringbuffer + s->ringbuffer_size;
+
+  return BROTLI_TRUE;
+}
+
+static BrotliDecoderErrorCode BROTLI_NOINLINE CopyUncompressedBlockToOutput(
+    size_t* available_out, uint8_t** next_out, size_t* total_out,
+    BrotliDecoderState* s) {
+  /* TODO: avoid allocation for single uncompressed block. */
+  if (!BrotliEnsureRingBuffer(s)) {
+    return BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_1);
+  }
+
+  /* State machine */
+  for (;;) {
+    switch (s->substate_uncompressed) {
+      case BROTLI_STATE_UNCOMPRESSED_NONE: {
+        int nbytes = (int)BrotliGetRemainingBytes(&s->br);
+        if (nbytes > s->meta_block_remaining_len) {
+          nbytes = s->meta_block_remaining_len;
+        }
+        if (s->pos + nbytes > s->ringbuffer_size) {
+          nbytes = s->ringbuffer_size - s->pos;
+        }
+        /* Copy remaining bytes from s->br.buf_ to ring-buffer. */
+        BrotliCopyBytes(&s->ringbuffer[s->pos], &s->br, (size_t)nbytes);
+        s->pos += nbytes;
+        s->meta_block_remaining_len -= nbytes;
+        if (s->pos < 1 << s->window_bits) {
+          if (s->meta_block_remaining_len == 0) {
+            return BROTLI_DECODER_SUCCESS;
+          }
+          return BROTLI_DECODER_NEEDS_MORE_INPUT;
+        }
+        s->substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_WRITE;
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_UNCOMPRESSED_WRITE: {
+        BrotliDecoderErrorCode result;
+        result = WriteRingBuffer(
+            s, available_out, next_out, total_out, BROTLI_FALSE);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          return result;
+        }
+        if (s->ringbuffer_size == 1 << s->window_bits) {
+          s->max_distance = s->max_backward_distance;
+        }
+        s->substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_NONE;
+        break;
+      }
+    }
+  }
+  BROTLI_DCHECK(0);  /* Unreachable */
+}
+
+/* Calculates the smallest feasible ring buffer.
+
+   If we know the data size is small, do not allocate more ring buffer
+   size than needed to reduce memory usage.
+
+   When this method is called, metablock size and flags MUST be decoded. */
+static void BROTLI_NOINLINE BrotliCalculateRingBufferSize(
+    BrotliDecoderState* s) {
+  int window_size = 1 << s->window_bits;
+  int new_ringbuffer_size = window_size;
+  /* We need at least 2 bytes of ring buffer size to get the last two
+     bytes for context from there */
+  int min_size = s->ringbuffer_size ? s->ringbuffer_size : 1024;
+  int output_size;
+
+  /* If maximum is already reached, no further extension is retired. */
+  if (s->ringbuffer_size == window_size) {
+    return;
+  }
+
+  /* Metadata blocks does not touch ring buffer. */
+  if (s->is_metadata) {
+    return;
+  }
+
+  if (!s->ringbuffer) {
+    output_size = 0;
+  } else {
+    output_size = s->pos;
+  }
+  output_size += s->meta_block_remaining_len;
+  min_size = min_size < output_size ? output_size : min_size;
+
+  if (!!s->canny_ringbuffer_allocation) {
+    /* Reduce ring buffer size to save memory when server is unscrupulous.
+       In worst case memory usage might be 1.5x bigger for a short period of
+       ring buffer reallocation. */
+    while ((new_ringbuffer_size >> 1) >= min_size) {
+      new_ringbuffer_size >>= 1;
+    }
+  }
+
+  s->new_ringbuffer_size = new_ringbuffer_size;
+}
+
+/* Reads 1..256 2-bit context modes. */
+static BrotliDecoderErrorCode ReadContextModes(BrotliDecoderState* s) {
+  BrotliBitReader* br = &s->br;
+  int i = s->loop_counter;
+
+  while (i < (int)s->num_block_types[0]) {
+    uint32_t bits;
+    if (!BrotliSafeReadBits(br, 2, &bits)) {
+      s->loop_counter = i;
+      return BROTLI_DECODER_NEEDS_MORE_INPUT;
+    }
+    s->context_modes[i] = (uint8_t)bits;
+    BROTLI_LOG_ARRAY_INDEX(s->context_modes, i);
+    i++;
+  }
+  return BROTLI_DECODER_SUCCESS;
+}
+
+static BROTLI_INLINE void TakeDistanceFromRingBuffer(BrotliDecoderState* s) {
+  int offset = s->distance_code - 3;
+  if (s->distance_code <= 3) {
+    /* Compensate double distance-ring-buffer roll for dictionary items. */
+    s->distance_context = 1 >> s->distance_code;
+    s->distance_code = s->dist_rb[(s->dist_rb_idx - offset) & 3];
+    s->dist_rb_idx -= s->distance_context;
+  } else {
+    int index_delta = 3;
+    int delta;
+    int base = s->distance_code - 10;
+    if (s->distance_code < 10) {
+      base = s->distance_code - 4;
+    } else {
+      index_delta = 2;
+    }
+    /* Unpack one of six 4-bit values. */
+    delta = ((0x605142 >> (4 * base)) & 0xF) - 3;
+    s->distance_code = s->dist_rb[(s->dist_rb_idx + index_delta) & 0x3] + delta;
+    if (s->distance_code <= 0) {
+      /* A huge distance will cause a BROTLI_FAILURE() soon.
+         This is a little faster than failing here. */
+      s->distance_code = 0x7FFFFFFF;
+    }
+  }
+}
+
+static BROTLI_INLINE BROTLI_BOOL SafeReadBits(
+    BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) {
+  if (n_bits != 0) {
+    return BrotliSafeReadBits(br, n_bits, val);
+  } else {
+    *val = 0;
+    return BROTLI_TRUE;
+  }
+}
+
+static BROTLI_INLINE BROTLI_BOOL SafeReadBits32(
+    BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) {
+  if (n_bits != 0) {
+    return BrotliSafeReadBits32(br, n_bits, val);
+  } else {
+    *val = 0;
+    return BROTLI_TRUE;
+  }
+}
+
+/*
+   RFC 7932 Section 4 with "..." shortenings and "[]" emendations.
+
+   Each distance ... is represented with a pair <distance code, extra bits>...
+   The distance code is encoded using a prefix code... The number of extra bits
+   can be 0..24... Two additional parameters: NPOSTFIX (0..3), and ...
+   NDIRECT (0..120) ... are encoded in the meta-block header...
+
+   The first 16 distance symbols ... reference past distances... ring buffer ...
+   Next NDIRECT distance symbols ... represent distances from 1 to NDIRECT...
+   [For] distance symbols 16 + NDIRECT and greater ... the number of extra bits
+   ... is given by the following formula:
+
+   [ xcode = dcode - NDIRECT - 16 ]
+   ndistbits = 1 + [ xcode ] >> (NPOSTFIX + 1)
+
+   ...
+*/
+
+/*
+   RFC 7932 Section 9.2 with "..." shortenings and "[]" emendations.
+
+   ... to get the actual value of the parameter NDIRECT, left-shift this
+   four-bit number by NPOSTFIX bits ...
+*/
+
+/* Remaining formulas from RFC 7932 Section 4 could be rewritten as following:
+
+     alphabet_size = 16 + NDIRECT + (max_distbits << (NPOSTFIX + 1))
+
+     half = ((xcode >> NPOSTFIX) & 1) << ndistbits
+     postfix = xcode & ((1 << NPOSTFIX) - 1)
+     range_start = 2 * (1 << ndistbits - 1 - 1)
+
+     distance = (range_start + half + extra) << NPOSTFIX + postfix + NDIRECT + 1
+
+   NB: ndistbits >= 1 -> range_start >= 0
+   NB: range_start has factor 2, as the range is covered by 2 "halves"
+   NB: extra -1 offset in range_start formula covers the absence of
+       ndistbits = 0 case
+   NB: when NPOSTFIX = 0, NDIRECT is not greater than 15
+
+   In other words, xcode has the following binary structure - XXXHPPP:
+    - XXX represent the number of extra distance bits
+    - H selects upper / lower range of distances
+    - PPP represent "postfix"
+
+  "Regular" distance encoding has NPOSTFIX = 0; omitting the postfix part
+  simplifies distance calculation.
+
+  Using NPOSTFIX > 0 allows cheaper encoding of regular structures, e.g. where
+  most of distances have the same reminder of division by 2/4/8. For example,
+  the table of int32_t values that come from different sources; if it is likely
+  that 3 highest bytes of values from the same source are the same, then
+  copy distance often looks like 4x + y.
+
+  Distance calculation could be rewritten to:
+
+    ndistbits = NDISTBITS(NDIRECT, NPOSTFIX)[dcode]
+    distance = OFFSET(NDIRECT, NPOSTFIX)[dcode] + extra << NPOSTFIX
+
+  NDISTBITS and OFFSET could be pre-calculated, as NDIRECT and NPOSTFIX could
+  change only once per meta-block.
+*/
+
+/* Calculates distance lookup table.
+   NB: it is possible to have all 64 tables precalculated. */
+static void CalculateDistanceLut(BrotliDecoderState* s) {
+  BrotliMetablockBodyArena* b = &s->arena.body;
+  uint32_t npostfix = s->distance_postfix_bits;
+  uint32_t ndirect = s->num_direct_distance_codes;
+  uint32_t alphabet_size_limit = s->distance_hgroup.alphabet_size_limit;
+  uint32_t postfix = 1u << npostfix;
+  uint32_t j;
+  uint32_t bits = 1;
+  uint32_t half = 0;
+
+  /* Skip short codes. */
+  uint32_t i = BROTLI_NUM_DISTANCE_SHORT_CODES;
+
+  /* Fill direct codes. */
+  for (j = 0; j < ndirect; ++j) {
+    b->dist_extra_bits[i] = 0;
+    b->dist_offset[i] = j + 1;
+    ++i;
+  }
+
+  /* Fill regular distance codes. */
+  while (i < alphabet_size_limit) {
+    uint32_t base = ndirect + ((((2 + half) << bits) - 4) << npostfix) + 1;
+    /* Always fill the complete group. */
+    for (j = 0; j < postfix; ++j) {
+      b->dist_extra_bits[i] = (uint8_t)bits;
+      b->dist_offset[i] = base + j;
+      ++i;
+    }
+    bits = bits + half;
+    half = half ^ 1;
+  }
+}
+
+/* Precondition: s->distance_code < 0. */
+static BROTLI_INLINE BROTLI_BOOL ReadDistanceInternal(
+    int safe, BrotliDecoderState* s, BrotliBitReader* br) {
+  BrotliMetablockBodyArena* b = &s->arena.body;
+  uint32_t code;
+  uint32_t bits;
+  BrotliBitReaderState memento;
+  HuffmanCode* distance_tree = s->distance_hgroup.htrees[s->dist_htree_index];
+  if (!safe) {
+    code = ReadSymbol(distance_tree, br);
+  } else {
+    BrotliBitReaderSaveState(br, &memento);
+    if (!SafeReadSymbol(distance_tree, br, &code)) {
+      return BROTLI_FALSE;
+    }
+  }
+  --s->block_length[2];
+  /* Convert the distance code to the actual distance by possibly
+     looking up past distances from the s->dist_rb. */
+  s->distance_context = 0;
+  if ((code & ~0xFu) == 0) {
+    s->distance_code = (int)code;
+    TakeDistanceFromRingBuffer(s);
+    return BROTLI_TRUE;
+  }
+  if (!safe) {
+    bits = BrotliReadBits32(br, b->dist_extra_bits[code]);
+  } else {
+    if (!SafeReadBits32(br, b->dist_extra_bits[code], &bits)) {
+      ++s->block_length[2];
+      BrotliBitReaderRestoreState(br, &memento);
+      return BROTLI_FALSE;
+    }
+  }
+  s->distance_code =
+      (int)(b->dist_offset[code] + (bits << s->distance_postfix_bits));
+  return BROTLI_TRUE;
+}
+
+static BROTLI_INLINE void ReadDistance(
+    BrotliDecoderState* s, BrotliBitReader* br) {
+  ReadDistanceInternal(0, s, br);
+}
+
+static BROTLI_INLINE BROTLI_BOOL SafeReadDistance(
+    BrotliDecoderState* s, BrotliBitReader* br) {
+  return ReadDistanceInternal(1, s, br);
+}
+
+static BROTLI_INLINE BROTLI_BOOL ReadCommandInternal(
+    int safe, BrotliDecoderState* s, BrotliBitReader* br, int* insert_length) {
+  uint32_t cmd_code;
+  uint32_t insert_len_extra = 0;
+  uint32_t copy_length;
+  CmdLutElement v;
+  BrotliBitReaderState memento;
+  if (!safe) {
+    cmd_code = ReadSymbol(s->htree_command, br);
+  } else {
+    BrotliBitReaderSaveState(br, &memento);
+    if (!SafeReadSymbol(s->htree_command, br, &cmd_code)) {
+      return BROTLI_FALSE;
+    }
+  }
+  v = kCmdLut[cmd_code];
+  s->distance_code = v.distance_code;
+  s->distance_context = v.context;
+  s->dist_htree_index = s->dist_context_map_slice[s->distance_context];
+  *insert_length = v.insert_len_offset;
+  if (!safe) {
+    if (BROTLI_PREDICT_FALSE(v.insert_len_extra_bits != 0)) {
+      insert_len_extra = BrotliReadBits24(br, v.insert_len_extra_bits);
+    }
+    copy_length = BrotliReadBits24(br, v.copy_len_extra_bits);
+  } else {
+    if (!SafeReadBits(br, v.insert_len_extra_bits, &insert_len_extra) ||
+        !SafeReadBits(br, v.copy_len_extra_bits, &copy_length)) {
+      BrotliBitReaderRestoreState(br, &memento);
+      return BROTLI_FALSE;
+    }
+  }
+  s->copy_length = (int)copy_length + v.copy_len_offset;
+  --s->block_length[1];
+  *insert_length += (int)insert_len_extra;
+  return BROTLI_TRUE;
+}
+
+static BROTLI_INLINE void ReadCommand(
+    BrotliDecoderState* s, BrotliBitReader* br, int* insert_length) {
+  ReadCommandInternal(0, s, br, insert_length);
+}
+
+static BROTLI_INLINE BROTLI_BOOL SafeReadCommand(
+    BrotliDecoderState* s, BrotliBitReader* br, int* insert_length) {
+  return ReadCommandInternal(1, s, br, insert_length);
+}
+
+static BROTLI_INLINE BROTLI_BOOL CheckInputAmount(
+    int safe, BrotliBitReader* const br, size_t num) {
+  if (safe) {
+    return BROTLI_TRUE;
+  }
+  return BrotliCheckInputAmount(br, num);
+}
+
+#define BROTLI_SAFE(METHOD)                       \
+  {                                               \
+    if (safe) {                                   \
+      if (!Safe##METHOD) {                        \
+        result = BROTLI_DECODER_NEEDS_MORE_INPUT; \
+        goto saveStateAndReturn;                  \
+      }                                           \
+    } else {                                      \
+      METHOD;                                     \
+    }                                             \
+  }
+
+static BROTLI_INLINE BrotliDecoderErrorCode ProcessCommandsInternal(
+    int safe, BrotliDecoderState* s) {
+  int pos = s->pos;
+  int i = s->loop_counter;
+  BrotliDecoderErrorCode result = BROTLI_DECODER_SUCCESS;
+  BrotliBitReader* br = &s->br;
+
+  if (!CheckInputAmount(safe, br, 28)) {
+    result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+    goto saveStateAndReturn;
+  }
+  if (!safe) {
+    BROTLI_UNUSED(BrotliWarmupBitReader(br));
+  }
+
+  /* Jump into state machine. */
+  if (s->state == BROTLI_STATE_COMMAND_BEGIN) {
+    goto CommandBegin;
+  } else if (s->state == BROTLI_STATE_COMMAND_INNER) {
+    goto CommandInner;
+  } else if (s->state == BROTLI_STATE_COMMAND_POST_DECODE_LITERALS) {
+    goto CommandPostDecodeLiterals;
+  } else if (s->state == BROTLI_STATE_COMMAND_POST_WRAP_COPY) {
+    goto CommandPostWrapCopy;
+  } else {
+    return BROTLI_FAILURE(BROTLI_DECODER_ERROR_UNREACHABLE);
+  }
+
+CommandBegin:
+  if (safe) {
+    s->state = BROTLI_STATE_COMMAND_BEGIN;
+  }
+  if (!CheckInputAmount(safe, br, 28)) {  /* 156 bits + 7 bytes */
+    s->state = BROTLI_STATE_COMMAND_BEGIN;
+    result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+    goto saveStateAndReturn;
+  }
+  if (BROTLI_PREDICT_FALSE(s->block_length[1] == 0)) {
+    BROTLI_SAFE(DecodeCommandBlockSwitch(s));
+    goto CommandBegin;
+  }
+  /* Read the insert/copy length in the command. */
+  BROTLI_SAFE(ReadCommand(s, br, &i));
+  BROTLI_LOG(("[ProcessCommandsInternal] pos = %d insert = %d copy = %d\n",
+              pos, i, s->copy_length));
+  if (i == 0) {
+    goto CommandPostDecodeLiterals;
+  }
+  s->meta_block_remaining_len -= i;
+
+CommandInner:
+  if (safe) {
+    s->state = BROTLI_STATE_COMMAND_INNER;
+  }
+  /* Read the literals in the command. */
+  if (s->trivial_literal_context) {
+    uint32_t bits;
+    uint32_t value;
+    PreloadSymbol(safe, s->literal_htree, br, &bits, &value);
+    do {
+      if (!CheckInputAmount(safe, br, 28)) {  /* 162 bits + 7 bytes */
+        s->state = BROTLI_STATE_COMMAND_INNER;
+        result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+        goto saveStateAndReturn;
+      }
+      if (BROTLI_PREDICT_FALSE(s->block_length[0] == 0)) {
+        BROTLI_SAFE(DecodeLiteralBlockSwitch(s));
+        PreloadSymbol(safe, s->literal_htree, br, &bits, &value);
+        if (!s->trivial_literal_context) goto CommandInner;
+      }
+      if (!safe) {
+        s->ringbuffer[pos] =
+            (uint8_t)ReadPreloadedSymbol(s->literal_htree, br, &bits, &value);
+      } else {
+        uint32_t literal;
+        if (!SafeReadSymbol(s->literal_htree, br, &literal)) {
+          result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+          goto saveStateAndReturn;
+        }
+        s->ringbuffer[pos] = (uint8_t)literal;
+      }
+      --s->block_length[0];
+      BROTLI_LOG_ARRAY_INDEX(s->ringbuffer, pos);
+      ++pos;
+      if (BROTLI_PREDICT_FALSE(pos == s->ringbuffer_size)) {
+        s->state = BROTLI_STATE_COMMAND_INNER_WRITE;
+        --i;
+        goto saveStateAndReturn;
+      }
+    } while (--i != 0);
+  } else {
+    uint8_t p1 = s->ringbuffer[(pos - 1) & s->ringbuffer_mask];
+    uint8_t p2 = s->ringbuffer[(pos - 2) & s->ringbuffer_mask];
+    do {
+      const HuffmanCode* hc;
+      uint8_t context;
+      if (!CheckInputAmount(safe, br, 28)) {  /* 162 bits + 7 bytes */
+        s->state = BROTLI_STATE_COMMAND_INNER;
+        result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+        goto saveStateAndReturn;
+      }
+      if (BROTLI_PREDICT_FALSE(s->block_length[0] == 0)) {
+        BROTLI_SAFE(DecodeLiteralBlockSwitch(s));
+        if (s->trivial_literal_context) goto CommandInner;
+      }
+      context = BROTLI_CONTEXT(p1, p2, s->context_lookup);
+      BROTLI_LOG_UINT(context);
+      hc = s->literal_hgroup.htrees[s->context_map_slice[context]];
+      p2 = p1;
+      if (!safe) {
+        p1 = (uint8_t)ReadSymbol(hc, br);
+      } else {
+        uint32_t literal;
+        if (!SafeReadSymbol(hc, br, &literal)) {
+          result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+          goto saveStateAndReturn;
+        }
+        p1 = (uint8_t)literal;
+      }
+      s->ringbuffer[pos] = p1;
+      --s->block_length[0];
+      BROTLI_LOG_UINT(s->context_map_slice[context]);
+      BROTLI_LOG_ARRAY_INDEX(s->ringbuffer, pos & s->ringbuffer_mask);
+      ++pos;
+      if (BROTLI_PREDICT_FALSE(pos == s->ringbuffer_size)) {
+        s->state = BROTLI_STATE_COMMAND_INNER_WRITE;
+        --i;
+        goto saveStateAndReturn;
+      }
+    } while (--i != 0);
+  }
+  BROTLI_LOG_UINT(s->meta_block_remaining_len);
+  if (BROTLI_PREDICT_FALSE(s->meta_block_remaining_len <= 0)) {
+    s->state = BROTLI_STATE_METABLOCK_DONE;
+    goto saveStateAndReturn;
+  }
+
+CommandPostDecodeLiterals:
+  if (safe) {
+    s->state = BROTLI_STATE_COMMAND_POST_DECODE_LITERALS;
+  }
+  if (s->distance_code >= 0) {
+    /* Implicit distance case. */
+    s->distance_context = s->distance_code ? 0 : 1;
+    --s->dist_rb_idx;
+    s->distance_code = s->dist_rb[s->dist_rb_idx & 3];
+  } else {
+    /* Read distance code in the command, unless it was implicitly zero. */
+    if (BROTLI_PREDICT_FALSE(s->block_length[2] == 0)) {
+      BROTLI_SAFE(DecodeDistanceBlockSwitch(s));
+    }
+    BROTLI_SAFE(ReadDistance(s, br));
+  }
+  BROTLI_LOG(("[ProcessCommandsInternal] pos = %d distance = %d\n",
+              pos, s->distance_code));
+  if (s->max_distance != s->max_backward_distance) {
+    s->max_distance =
+        (pos < s->max_backward_distance) ? pos : s->max_backward_distance;
+  }
+  i = s->copy_length;
+  /* Apply copy of LZ77 back-reference, or static dictionary reference if
+     the distance is larger than the max LZ77 distance */
+  if (s->distance_code > s->max_distance) {
+    /* The maximum allowed distance is BROTLI_MAX_ALLOWED_DISTANCE = 0x7FFFFFFC.
+       With this choice, no signed overflow can occur after decoding
+       a special distance code (e.g., after adding 3 to the last distance). */
+    if (s->distance_code > BROTLI_MAX_ALLOWED_DISTANCE) {
+      BROTLI_LOG(("Invalid backward reference. pos: %d distance: %d "
+          "len: %d bytes left: %d\n",
+          pos, s->distance_code, i, s->meta_block_remaining_len));
+      return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_DISTANCE);
+    }
+    if (i >= BROTLI_MIN_DICTIONARY_WORD_LENGTH &&
+        i <= BROTLI_MAX_DICTIONARY_WORD_LENGTH) {
+      int address = s->distance_code - s->max_distance - 1;
+      const BrotliDictionary* words = s->dictionary;
+      const BrotliTransforms* transforms = s->transforms;
+      int offset = (int)s->dictionary->offsets_by_length[i];
+      uint32_t shift = s->dictionary->size_bits_by_length[i];
+
+      int mask = (int)BitMask(shift);
+      int word_idx = address & mask;
+      int transform_idx = address >> shift;
+      /* Compensate double distance-ring-buffer roll. */
+      s->dist_rb_idx += s->distance_context;
+      offset += word_idx * i;
+      if (BROTLI_PREDICT_FALSE(!words->data)) {
+        return BROTLI_FAILURE(BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET);
+      }
+      if (transform_idx < (int)transforms->num_transforms) {
+        const uint8_t* word = &words->data[offset];
+        int len = i;
+        if (transform_idx == transforms->cutOffTransforms[0]) {
+          memcpy(&s->ringbuffer[pos], word, (size_t)len);
+          BROTLI_LOG(("[ProcessCommandsInternal] dictionary word: [%.*s]\n",
+                      len, word));
+        } else {
+          len = BrotliTransformDictionaryWord(&s->ringbuffer[pos], word, len,
+              transforms, transform_idx);
+          BROTLI_LOG(("[ProcessCommandsInternal] dictionary word: [%.*s],"
+                      " transform_idx = %d, transformed: [%.*s]\n",
+                      i, word, transform_idx, len, &s->ringbuffer[pos]));
+        }
+        pos += len;
+        s->meta_block_remaining_len -= len;
+        if (pos >= s->ringbuffer_size) {
+          s->state = BROTLI_STATE_COMMAND_POST_WRITE_1;
+          goto saveStateAndReturn;
+        }
+      } else {
+        BROTLI_LOG(("Invalid backward reference. pos: %d distance: %d "
+            "len: %d bytes left: %d\n",
+            pos, s->distance_code, i, s->meta_block_remaining_len));
+        return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_TRANSFORM);
+      }
+    } else {
+      BROTLI_LOG(("Invalid backward reference. pos: %d distance: %d "
+          "len: %d bytes left: %d\n",
+          pos, s->distance_code, i, s->meta_block_remaining_len));
+      return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_DICTIONARY);
+    }
+  } else {
+    int src_start = (pos - s->distance_code) & s->ringbuffer_mask;
+    uint8_t* copy_dst = &s->ringbuffer[pos];
+    uint8_t* copy_src = &s->ringbuffer[src_start];
+    int dst_end = pos + i;
+    int src_end = src_start + i;
+    /* Update the recent distances cache. */
+    s->dist_rb[s->dist_rb_idx & 3] = s->distance_code;
+    ++s->dist_rb_idx;
+    s->meta_block_remaining_len -= i;
+    /* There are 32+ bytes of slack in the ring-buffer allocation.
+       Also, we have 16 short codes, that make these 16 bytes irrelevant
+       in the ring-buffer. Let's copy over them as a first guess. */
+    memmove16(copy_dst, copy_src);
+    if (src_end > pos && dst_end > src_start) {
+      /* Regions intersect. */
+      goto CommandPostWrapCopy;
+    }
+    if (dst_end >= s->ringbuffer_size || src_end >= s->ringbuffer_size) {
+      /* At least one region wraps. */
+      goto CommandPostWrapCopy;
+    }
+    pos += i;
+    if (i > 16) {
+      if (i > 32) {
+        memcpy(copy_dst + 16, copy_src + 16, (size_t)(i - 16));
+      } else {
+        /* This branch covers about 45% cases.
+           Fixed size short copy allows more compiler optimizations. */
+        memmove16(copy_dst + 16, copy_src + 16);
+      }
+    }
+  }
+  BROTLI_LOG_UINT(s->meta_block_remaining_len);
+  if (s->meta_block_remaining_len <= 0) {
+    /* Next metablock, if any. */
+    s->state = BROTLI_STATE_METABLOCK_DONE;
+    goto saveStateAndReturn;
+  } else {
+    goto CommandBegin;
+  }
+CommandPostWrapCopy:
+  {
+    int wrap_guard = s->ringbuffer_size - pos;
+    while (--i >= 0) {
+      s->ringbuffer[pos] =
+          s->ringbuffer[(pos - s->distance_code) & s->ringbuffer_mask];
+      ++pos;
+      if (BROTLI_PREDICT_FALSE(--wrap_guard == 0)) {
+        s->state = BROTLI_STATE_COMMAND_POST_WRITE_2;
+        goto saveStateAndReturn;
+      }
+    }
+  }
+  if (s->meta_block_remaining_len <= 0) {
+    /* Next metablock, if any. */
+    s->state = BROTLI_STATE_METABLOCK_DONE;
+    goto saveStateAndReturn;
+  } else {
+    goto CommandBegin;
+  }
+
+saveStateAndReturn:
+  s->pos = pos;
+  s->loop_counter = i;
+  return result;
+}
+
+#undef BROTLI_SAFE
+
+static BROTLI_NOINLINE BrotliDecoderErrorCode ProcessCommands(
+    BrotliDecoderState* s) {
+  return ProcessCommandsInternal(0, s);
+}
+
+static BROTLI_NOINLINE BrotliDecoderErrorCode SafeProcessCommands(
+    BrotliDecoderState* s) {
+  return ProcessCommandsInternal(1, s);
+}
+
+BrotliDecoderResult BrotliDecoderDecompress(
+    size_t encoded_size, const uint8_t* encoded_buffer, size_t* decoded_size,
+    uint8_t* decoded_buffer) {
+  BrotliDecoderState s;
+  BrotliDecoderResult result;
+  size_t total_out = 0;
+  size_t available_in = encoded_size;
+  const uint8_t* next_in = encoded_buffer;
+  size_t available_out = *decoded_size;
+  uint8_t* next_out = decoded_buffer;
+  if (!BrotliDecoderStateInit(&s, 0, 0, 0)) {
+    return BROTLI_DECODER_RESULT_ERROR;
+  }
+  result = BrotliDecoderDecompressStream(
+      &s, &available_in, &next_in, &available_out, &next_out, &total_out);
+  *decoded_size = total_out;
+  BrotliDecoderStateCleanup(&s);
+  if (result != BROTLI_DECODER_RESULT_SUCCESS) {
+    result = BROTLI_DECODER_RESULT_ERROR;
+  }
+  return result;
+}
+
+/* Invariant: input stream is never overconsumed:
+    - invalid input implies that the whole stream is invalid -> any amount of
+      input could be read and discarded
+    - when result is "needs more input", then at least one more byte is REQUIRED
+      to complete decoding; all input data MUST be consumed by decoder, so
+      client could swap the input buffer
+    - when result is "needs more output" decoder MUST ensure that it doesn't
+      hold more than 7 bits in bit reader; this saves client from swapping input
+      buffer ahead of time
+    - when result is "success" decoder MUST return all unused data back to input
+      buffer; this is possible because the invariant is held on enter */
+BrotliDecoderResult BrotliDecoderDecompressStream(
+    BrotliDecoderState* s, size_t* available_in, const uint8_t** next_in,
+    size_t* available_out, uint8_t** next_out, size_t* total_out) {
+  BrotliDecoderErrorCode result = BROTLI_DECODER_SUCCESS;
+  BrotliBitReader* br = &s->br;
+  /* Ensure that |total_out| is set, even if no data will ever be pushed out. */
+  if (total_out) {
+    *total_out = s->partial_pos_out;
+  }
+  /* Do not try to process further in a case of unrecoverable error. */
+  if ((int)s->error_code < 0) {
+    return BROTLI_DECODER_RESULT_ERROR;
+  }
+  if (*available_out && (!next_out || !*next_out)) {
+    return SaveErrorCode(
+        s, BROTLI_FAILURE(BROTLI_DECODER_ERROR_INVALID_ARGUMENTS));
+  }
+  if (!*available_out) next_out = 0;
+  if (s->buffer_length == 0) {  /* Just connect bit reader to input stream. */
+    br->avail_in = *available_in;
+    br->next_in = *next_in;
+  } else {
+    /* At least one byte of input is required. More than one byte of input may
+       be required to complete the transaction -> reading more data must be
+       done in a loop -> do it in a main loop. */
+    result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+    br->next_in = &s->buffer.u8[0];
+  }
+  /* State machine */
+  for (;;) {
+    if (result != BROTLI_DECODER_SUCCESS) {
+      /* Error, needs more input/output. */
+      if (result == BROTLI_DECODER_NEEDS_MORE_INPUT) {
+        if (s->ringbuffer != 0) {  /* Pro-actively push output. */
+          BrotliDecoderErrorCode intermediate_result = WriteRingBuffer(s,
+              available_out, next_out, total_out, BROTLI_TRUE);
+          /* WriteRingBuffer checks s->meta_block_remaining_len validity. */
+          if ((int)intermediate_result < 0) {
+            result = intermediate_result;
+            break;
+          }
+        }
+        if (s->buffer_length != 0) {  /* Used with internal buffer. */
+          if (br->avail_in == 0) {
+            /* Successfully finished read transaction.
+               Accumulator contains less than 8 bits, because internal buffer
+               is expanded byte-by-byte until it is enough to complete read. */
+            s->buffer_length = 0;
+            /* Switch to input stream and restart. */
+            result = BROTLI_DECODER_SUCCESS;
+            br->avail_in = *available_in;
+            br->next_in = *next_in;
+            continue;
+          } else if (*available_in != 0) {
+            /* Not enough data in buffer, but can take one more byte from
+               input stream. */
+            result = BROTLI_DECODER_SUCCESS;
+            s->buffer.u8[s->buffer_length] = **next_in;
+            s->buffer_length++;
+            br->avail_in = s->buffer_length;
+            (*next_in)++;
+            (*available_in)--;
+            /* Retry with more data in buffer. */
+            continue;
+          }
+          /* Can't finish reading and no more input. */
+          break;
+        } else {  /* Input stream doesn't contain enough input. */
+          /* Copy tail to internal buffer and return. */
+          *next_in = br->next_in;
+          *available_in = br->avail_in;
+          while (*available_in) {
+            s->buffer.u8[s->buffer_length] = **next_in;
+            s->buffer_length++;
+            (*next_in)++;
+            (*available_in)--;
+          }
+          break;
+        }
+        /* Unreachable. */
+      }
+
+      /* Fail or needs more output. */
+
+      if (s->buffer_length != 0) {
+        /* Just consumed the buffered input and produced some output. Otherwise
+           it would result in "needs more input". Reset internal buffer. */
+        s->buffer_length = 0;
+      } else {
+        /* Using input stream in last iteration. When decoder switches to input
+           stream it has less than 8 bits in accumulator, so it is safe to
+           return unused accumulator bits there. */
+        BrotliBitReaderUnload(br);
+        *available_in = br->avail_in;
+        *next_in = br->next_in;
+      }
+      break;
+    }
+    switch (s->state) {
+      case BROTLI_STATE_UNINITED:
+        /* Prepare to the first read. */
+        if (!BrotliWarmupBitReader(br)) {
+          result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+          break;
+        }
+        /* Decode window size. */
+        result = DecodeWindowBits(s, br);  /* Reads 1..8 bits. */
+        if (result != BROTLI_DECODER_SUCCESS) {
+          break;
+        }
+        if (s->large_window) {
+          s->state = BROTLI_STATE_LARGE_WINDOW_BITS;
+          break;
+        }
+        s->state = BROTLI_STATE_INITIALIZE;
+        break;
+
+      case BROTLI_STATE_LARGE_WINDOW_BITS:
+        if (!BrotliSafeReadBits(br, 6, &s->window_bits)) {
+          result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+          break;
+        }
+        if (s->window_bits < BROTLI_LARGE_MIN_WBITS ||
+            s->window_bits > BROTLI_LARGE_MAX_WBITS) {
+          result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS);
+          break;
+        }
+        s->state = BROTLI_STATE_INITIALIZE;
+      /* Fall through. */
+
+      case BROTLI_STATE_INITIALIZE:
+        BROTLI_LOG_UINT(s->window_bits);
+        /* Maximum distance, see section 9.1. of the spec. */
+        s->max_backward_distance = (1 << s->window_bits) - BROTLI_WINDOW_GAP;
+
+        /* Allocate memory for both block_type_trees and block_len_trees. */
+        s->block_type_trees = (HuffmanCode*)BROTLI_DECODER_ALLOC(s,
+            sizeof(HuffmanCode) * 3 *
+                (BROTLI_HUFFMAN_MAX_SIZE_258 + BROTLI_HUFFMAN_MAX_SIZE_26));
+        if (s->block_type_trees == 0) {
+          result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_BLOCK_TYPE_TREES);
+          break;
+        }
+        s->block_len_trees =
+            s->block_type_trees + 3 * BROTLI_HUFFMAN_MAX_SIZE_258;
+
+        s->state = BROTLI_STATE_METABLOCK_BEGIN;
+      /* Fall through. */
+
+      case BROTLI_STATE_METABLOCK_BEGIN:
+        BrotliDecoderStateMetablockBegin(s);
+        BROTLI_LOG_UINT(s->pos);
+        s->state = BROTLI_STATE_METABLOCK_HEADER;
+      /* Fall through. */
+
+      case BROTLI_STATE_METABLOCK_HEADER:
+        result = DecodeMetaBlockLength(s, br);  /* Reads 2 - 31 bits. */
+        if (result != BROTLI_DECODER_SUCCESS) {
+          break;
+        }
+        BROTLI_LOG_UINT(s->is_last_metablock);
+        BROTLI_LOG_UINT(s->meta_block_remaining_len);
+        BROTLI_LOG_UINT(s->is_metadata);
+        BROTLI_LOG_UINT(s->is_uncompressed);
+        if (s->is_metadata || s->is_uncompressed) {
+          if (!BrotliJumpToByteBoundary(br)) {
+            result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_PADDING_1);
+            break;
+          }
+        }
+        if (s->is_metadata) {
+          s->state = BROTLI_STATE_METADATA;
+          break;
+        }
+        if (s->meta_block_remaining_len == 0) {
+          s->state = BROTLI_STATE_METABLOCK_DONE;
+          break;
+        }
+        BrotliCalculateRingBufferSize(s);
+        if (s->is_uncompressed) {
+          s->state = BROTLI_STATE_UNCOMPRESSED;
+          break;
+        }
+        s->state = BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_HEADER;
+      /* Fall through. */
+
+      case BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_HEADER: {
+        BrotliMetablockHeaderArena* h = &s->arena.header;
+        s->loop_counter = 0;
+        /* Initialize compressed metablock header arena. */
+        h->sub_loop_counter = 0;
+        /* Make small negative indexes addressable. */
+        h->symbol_lists =
+            &h->symbols_lists_array[BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1];
+        h->substate_huffman = BROTLI_STATE_HUFFMAN_NONE;
+        h->substate_tree_group = BROTLI_STATE_TREE_GROUP_NONE;
+        h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_NONE;
+        s->state = BROTLI_STATE_HUFFMAN_CODE_0;
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_HUFFMAN_CODE_0:
+        if (s->loop_counter >= 3) {
+          s->state = BROTLI_STATE_METABLOCK_HEADER_2;
+          break;
+        }
+        /* Reads 1..11 bits. */
+        result = DecodeVarLenUint8(s, br, &s->num_block_types[s->loop_counter]);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          break;
+        }
+        s->num_block_types[s->loop_counter]++;
+        BROTLI_LOG_UINT(s->num_block_types[s->loop_counter]);
+        if (s->num_block_types[s->loop_counter] < 2) {
+          s->loop_counter++;
+          break;
+        }
+        s->state = BROTLI_STATE_HUFFMAN_CODE_1;
+      /* Fall through. */
+
+      case BROTLI_STATE_HUFFMAN_CODE_1: {
+        uint32_t alphabet_size = s->num_block_types[s->loop_counter] + 2;
+        int tree_offset = s->loop_counter * BROTLI_HUFFMAN_MAX_SIZE_258;
+        result = ReadHuffmanCode(alphabet_size, alphabet_size,
+            &s->block_type_trees[tree_offset], NULL, s);
+        if (result != BROTLI_DECODER_SUCCESS) break;
+        s->state = BROTLI_STATE_HUFFMAN_CODE_2;
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_HUFFMAN_CODE_2: {
+        uint32_t alphabet_size = BROTLI_NUM_BLOCK_LEN_SYMBOLS;
+        int tree_offset = s->loop_counter * BROTLI_HUFFMAN_MAX_SIZE_26;
+        result = ReadHuffmanCode(alphabet_size, alphabet_size,
+            &s->block_len_trees[tree_offset], NULL, s);
+        if (result != BROTLI_DECODER_SUCCESS) break;
+        s->state = BROTLI_STATE_HUFFMAN_CODE_3;
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_HUFFMAN_CODE_3: {
+        int tree_offset = s->loop_counter * BROTLI_HUFFMAN_MAX_SIZE_26;
+        if (!SafeReadBlockLength(s, &s->block_length[s->loop_counter],
+            &s->block_len_trees[tree_offset], br)) {
+          result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+          break;
+        }
+        BROTLI_LOG_UINT(s->block_length[s->loop_counter]);
+        s->loop_counter++;
+        s->state = BROTLI_STATE_HUFFMAN_CODE_0;
+        break;
+      }
+
+      case BROTLI_STATE_UNCOMPRESSED: {
+        result = CopyUncompressedBlockToOutput(
+            available_out, next_out, total_out, s);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          break;
+        }
+        s->state = BROTLI_STATE_METABLOCK_DONE;
+        break;
+      }
+
+      case BROTLI_STATE_METADATA:
+        for (; s->meta_block_remaining_len > 0; --s->meta_block_remaining_len) {
+          uint32_t bits;
+          /* Read one byte and ignore it. */
+          if (!BrotliSafeReadBits(br, 8, &bits)) {
+            result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+            break;
+          }
+        }
+        if (result == BROTLI_DECODER_SUCCESS) {
+          s->state = BROTLI_STATE_METABLOCK_DONE;
+        }
+        break;
+
+      case BROTLI_STATE_METABLOCK_HEADER_2: {
+        uint32_t bits;
+        if (!BrotliSafeReadBits(br, 6, &bits)) {
+          result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+          break;
+        }
+        s->distance_postfix_bits = bits & BitMask(2);
+        bits >>= 2;
+        s->num_direct_distance_codes = bits << s->distance_postfix_bits;
+        BROTLI_LOG_UINT(s->num_direct_distance_codes);
+        BROTLI_LOG_UINT(s->distance_postfix_bits);
+        s->context_modes =
+            (uint8_t*)BROTLI_DECODER_ALLOC(s, (size_t)s->num_block_types[0]);
+        if (s->context_modes == 0) {
+          result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MODES);
+          break;
+        }
+        s->loop_counter = 0;
+        s->state = BROTLI_STATE_CONTEXT_MODES;
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_CONTEXT_MODES:
+        result = ReadContextModes(s);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          break;
+        }
+        s->state = BROTLI_STATE_CONTEXT_MAP_1;
+      /* Fall through. */
+
+      case BROTLI_STATE_CONTEXT_MAP_1:
+        result = DecodeContextMap(
+            s->num_block_types[0] << BROTLI_LITERAL_CONTEXT_BITS,
+            &s->num_literal_htrees, &s->context_map, s);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          break;
+        }
+        DetectTrivialLiteralBlockTypes(s);
+        s->state = BROTLI_STATE_CONTEXT_MAP_2;
+      /* Fall through. */
+
+      case BROTLI_STATE_CONTEXT_MAP_2: {
+        uint32_t npostfix = s->distance_postfix_bits;
+        uint32_t ndirect = s->num_direct_distance_codes;
+        uint32_t distance_alphabet_size_max = BROTLI_DISTANCE_ALPHABET_SIZE(
+            npostfix, ndirect, BROTLI_MAX_DISTANCE_BITS);
+        uint32_t distance_alphabet_size_limit = distance_alphabet_size_max;
+        BROTLI_BOOL allocation_success = BROTLI_TRUE;
+        if (s->large_window) {
+          BrotliDistanceCodeLimit limit = BrotliCalculateDistanceCodeLimit(
+              BROTLI_MAX_ALLOWED_DISTANCE, npostfix, ndirect);
+          distance_alphabet_size_max = BROTLI_DISTANCE_ALPHABET_SIZE(
+              npostfix, ndirect, BROTLI_LARGE_MAX_DISTANCE_BITS);
+          distance_alphabet_size_limit = limit.max_alphabet_size;
+        }
+        result = DecodeContextMap(
+            s->num_block_types[2] << BROTLI_DISTANCE_CONTEXT_BITS,
+            &s->num_dist_htrees, &s->dist_context_map, s);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          break;
+        }
+        allocation_success &= BrotliDecoderHuffmanTreeGroupInit(
+            s, &s->literal_hgroup, BROTLI_NUM_LITERAL_SYMBOLS,
+            BROTLI_NUM_LITERAL_SYMBOLS, s->num_literal_htrees);
+        allocation_success &= BrotliDecoderHuffmanTreeGroupInit(
+            s, &s->insert_copy_hgroup, BROTLI_NUM_COMMAND_SYMBOLS,
+            BROTLI_NUM_COMMAND_SYMBOLS, s->num_block_types[1]);
+        allocation_success &= BrotliDecoderHuffmanTreeGroupInit(
+            s, &s->distance_hgroup, distance_alphabet_size_max,
+            distance_alphabet_size_limit, s->num_dist_htrees);
+        if (!allocation_success) {
+          return SaveErrorCode(s,
+              BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_TREE_GROUPS));
+        }
+        s->loop_counter = 0;
+        s->state = BROTLI_STATE_TREE_GROUP;
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_TREE_GROUP: {
+        HuffmanTreeGroup* hgroup = NULL;
+        switch (s->loop_counter) {
+          case 0: hgroup = &s->literal_hgroup; break;
+          case 1: hgroup = &s->insert_copy_hgroup; break;
+          case 2: hgroup = &s->distance_hgroup; break;
+          default: return SaveErrorCode(s, BROTLI_FAILURE(
+              BROTLI_DECODER_ERROR_UNREACHABLE));
+        }
+        result = HuffmanTreeGroupDecode(hgroup, s);
+        if (result != BROTLI_DECODER_SUCCESS) break;
+        s->loop_counter++;
+        if (s->loop_counter < 3) {
+          break;
+        }
+        s->state = BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_BODY;
+      }
+      /* Fall through. */
+
+      case BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_BODY:
+        PrepareLiteralDecoding(s);
+        s->dist_context_map_slice = s->dist_context_map;
+        s->htree_command = s->insert_copy_hgroup.htrees[0];
+        if (!BrotliEnsureRingBuffer(s)) {
+          result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_2);
+          break;
+        }
+        CalculateDistanceLut(s);
+        s->state = BROTLI_STATE_COMMAND_BEGIN;
+      /* Fall through. */
+
+      case BROTLI_STATE_COMMAND_BEGIN:
+      /* Fall through. */
+      case BROTLI_STATE_COMMAND_INNER:
+      /* Fall through. */
+      case BROTLI_STATE_COMMAND_POST_DECODE_LITERALS:
+      /* Fall through. */
+      case BROTLI_STATE_COMMAND_POST_WRAP_COPY:
+        result = ProcessCommands(s);
+        if (result == BROTLI_DECODER_NEEDS_MORE_INPUT) {
+          result = SafeProcessCommands(s);
+        }
+        break;
+
+      case BROTLI_STATE_COMMAND_INNER_WRITE:
+      /* Fall through. */
+      case BROTLI_STATE_COMMAND_POST_WRITE_1:
+      /* Fall through. */
+      case BROTLI_STATE_COMMAND_POST_WRITE_2:
+        result = WriteRingBuffer(
+            s, available_out, next_out, total_out, BROTLI_FALSE);
+        if (result != BROTLI_DECODER_SUCCESS) {
+          break;
+        }
+        WrapRingBuffer(s);
+        if (s->ringbuffer_size == 1 << s->window_bits) {
+          s->max_distance = s->max_backward_distance;
+        }
+        if (s->state == BROTLI_STATE_COMMAND_POST_WRITE_1) {
+          if (s->meta_block_remaining_len == 0) {
+            /* Next metablock, if any. */
+            s->state = BROTLI_STATE_METABLOCK_DONE;
+          } else {
+            s->state = BROTLI_STATE_COMMAND_BEGIN;
+          }
+          break;
+        } else if (s->state == BROTLI_STATE_COMMAND_POST_WRITE_2) {
+          s->state = BROTLI_STATE_COMMAND_POST_WRAP_COPY;
+        } else {  /* BROTLI_STATE_COMMAND_INNER_WRITE */
+          if (s->loop_counter == 0) {
+            if (s->meta_block_remaining_len == 0) {
+              s->state = BROTLI_STATE_METABLOCK_DONE;
+            } else {
+              s->state = BROTLI_STATE_COMMAND_POST_DECODE_LITERALS;
+            }
+            break;
+          }
+          s->state = BROTLI_STATE_COMMAND_INNER;
+        }
+        break;
+
+      case BROTLI_STATE_METABLOCK_DONE:
+        if (s->meta_block_remaining_len < 0) {
+          result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_2);
+          break;
+        }
+        BrotliDecoderStateCleanupAfterMetablock(s);
+        if (!s->is_last_metablock) {
+          s->state = BROTLI_STATE_METABLOCK_BEGIN;
+          break;
+        }
+        if (!BrotliJumpToByteBoundary(br)) {
+          result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_PADDING_2);
+          break;
+        }
+        if (s->buffer_length == 0) {
+          BrotliBitReaderUnload(br);
+          *available_in = br->avail_in;
+          *next_in = br->next_in;
+        }
+        s->state = BROTLI_STATE_DONE;
+      /* Fall through. */
+
+      case BROTLI_STATE_DONE:
+        if (s->ringbuffer != 0) {
+          result = WriteRingBuffer(
+              s, available_out, next_out, total_out, BROTLI_TRUE);
+          if (result != BROTLI_DECODER_SUCCESS) {
+            break;
+          }
+        }
+        return SaveErrorCode(s, result);
+    }
+  }
+  return SaveErrorCode(s, result);
+}
+
+BROTLI_BOOL BrotliDecoderHasMoreOutput(const BrotliDecoderState* s) {
+  /* After unrecoverable error remaining output is considered nonsensical. */
+  if ((int)s->error_code < 0) {
+    return BROTLI_FALSE;
+  }
+  return TO_BROTLI_BOOL(
+      s->ringbuffer != 0 && UnwrittenBytes(s, BROTLI_FALSE) != 0);
+}
+
+const uint8_t* BrotliDecoderTakeOutput(BrotliDecoderState* s, size_t* size) {
+  uint8_t* result = 0;
+  size_t available_out = *size ? *size : 1u << 24;
+  size_t requested_out = available_out;
+  BrotliDecoderErrorCode status;
+  if ((s->ringbuffer == 0) || ((int)s->error_code < 0)) {
+    *size = 0;
+    return 0;
+  }
+  WrapRingBuffer(s);
+  status = WriteRingBuffer(s, &available_out, &result, 0, BROTLI_TRUE);
+  /* Either WriteRingBuffer returns those "success" codes... */
+  if (status == BROTLI_DECODER_SUCCESS ||
+      status == BROTLI_DECODER_NEEDS_MORE_OUTPUT) {
+    *size = requested_out - available_out;
+  } else {
+    /* ... or stream is broken. Normally this should be caught by
+       BrotliDecoderDecompressStream, this is just a safeguard. */
+    if ((int)status < 0) SaveErrorCode(s, status);
+    *size = 0;
+    result = 0;
+  }
+  return result;
+}
+
+BROTLI_BOOL BrotliDecoderIsUsed(const BrotliDecoderState* s) {
+  return TO_BROTLI_BOOL(s->state != BROTLI_STATE_UNINITED ||
+      BrotliGetAvailableBits(&s->br) != 0);
+}
+
+BROTLI_BOOL BrotliDecoderIsFinished(const BrotliDecoderState* s) {
+  return TO_BROTLI_BOOL(s->state == BROTLI_STATE_DONE) &&
+      !BrotliDecoderHasMoreOutput(s);
+}
+
+BrotliDecoderErrorCode BrotliDecoderGetErrorCode(const BrotliDecoderState* s) {
+  return (BrotliDecoderErrorCode)s->error_code;
+}
+
+const char* BrotliDecoderErrorString(BrotliDecoderErrorCode c) {
+  switch (c) {
+#define BROTLI_ERROR_CODE_CASE_(PREFIX, NAME, CODE) \
+    case BROTLI_DECODER ## PREFIX ## NAME: return #NAME;
+#define BROTLI_NOTHING_
+    BROTLI_DECODER_ERROR_CODES_LIST(BROTLI_ERROR_CODE_CASE_, BROTLI_NOTHING_)
+#undef BROTLI_ERROR_CODE_CASE_
+#undef BROTLI_NOTHING_
+    default: return "INVALID";
+  }
+}
+
+uint32_t BrotliDecoderVersion() {
+  return BROTLI_VERSION;
+}
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}  /* extern "C" */
+#endif