Python2/PyMuPDF: mupdf-source/thirdparty/brotli/c/dec/decode.c comparison

comparison mupdf-source/thirdparty/brotli/c/dec/decode.c @ 2:b50eed0cc0ef upstream

ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.

author	Franz Glasner <fzglas.hg@dom66.de>
date	Mon, 15 Sep 2025 11:43:07 +0200
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children

comparison

equal deleted inserted replaced

-:1d09e1dec1d9
+:b50eed0cc0ef
+/* 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/shared_dictionary_internal.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:
+255 prefix + 32 base + 255 suffix */
+static const brotli_reg_t kRingBufferWriteAheadSlack = 542;
+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, size_t consumed_input) {
+s->error_code = (int)e;
+s->used_input += consumed_input;
+if ((s->buffer_length != 0) && (s->br.next_in == s->br.last_in)) {
+/* If internal buffer is depleted at last, reset it. */
+s->buffer_length = 0;
+}
+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) {
+brotli_reg_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 = (17u + n) & 63u;
+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 = (8u + n) & 63u;
+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, brotli_reg_t* value) {
+brotli_reg_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 = ((brotli_reg_t)1U << *value) + bits;
+s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE;
+return BROTLI_DECODER_SUCCESS;
+default:
+return
+BROTLI_FAILURE(BROTLI_DECODER_ERROR_UNREACHABLE);  /* COV_NF_LINE */
+}
+}
+/* Decodes a metablock length and flags by reading 2 - 31 bits. */
+static BrotliDecoderErrorCode BROTLI_NOINLINE DecodeMetaBlockLength(
+BrotliDecoderState* s, BrotliBitReader* br) {
+brotli_reg_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);  /* COV_NF_LINE */
+}
+}
+}
+/* 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 brotli_reg_t DecodeSymbol(brotli_reg_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) {
+brotli_reg_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 brotli_reg_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, brotli_reg_t* result) {
+brotli_reg_t val;
+brotli_reg_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 = 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, brotli_reg_t* result) {
+brotli_reg_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,
+brotli_reg_t* bits,
+brotli_reg_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 brotli_reg_t ReadPreloadedSymbol(const HuffmanCode* table,
+BrotliBitReader* br,
+brotli_reg_t* bits,
+brotli_reg_t* value) {
+brotli_reg_t result = *value;
+if (BROTLI_PREDICT_FALSE(*bits > HUFFMAN_TABLE_BITS)) {
+brotli_reg_t val = BrotliGet16BitsUnmasked(br);
+const HuffmanCode* ext = table + (val & HUFFMAN_TABLE_MASK) + *value;
+brotli_reg_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;
+}
+/* Reads up to limit symbols from br and copies them into ringbuffer,
+starting from pos. Caller must ensure that there is enough space
+for the write. Returns the amount of symbols actually copied. */
+static BROTLI_INLINE int BrotliCopyPreloadedSymbolsToU8(const HuffmanCode* table,
+BrotliBitReader* br,
+brotli_reg_t* bits,
+brotli_reg_t* value,
+uint8_t* ringbuffer,
+int pos,
+const int limit) {
+/* Calculate range where CheckInputAmount is always true.
+Start with the number of bytes we can read. */
+int64_t new_lim = br->guard_in - br->next_in;
+/* Convert to bits, since sybmols use variable number of bits. */
+new_lim *= 8;
+/* At most 15 bits per symbol, so this is safe. */
+new_lim /= 15;
+const int kMaximalOverread = 4;
+int pos_limit = limit;
+int copies = 0;
+if ((new_lim - kMaximalOverread) <= limit) {
+// Safe cast, since new_lim is already < num_steps
+pos_limit = (int)(new_lim - kMaximalOverread);
+}
+if (pos_limit < 0) {
+pos_limit = 0;
+}
+copies = pos_limit;
+pos_limit += pos;
+/* Fast path, caller made sure it is safe to write,
+we verified that is is safe to read. */
+for (; pos < pos_limit; pos++) {
+BROTLI_DCHECK(BrotliCheckInputAmount(br));
+ringbuffer[pos] = (uint8_t)ReadPreloadedSymbol(table, br, bits, value);
+BROTLI_LOG_ARRAY_INDEX(ringbuffer, pos);
+}
+/* Do the remainder, caller made sure it is safe to write,
+we need to bverify that it is safe to read. */
+while (BrotliCheckInputAmount(br) && copies < limit) {
+ringbuffer[pos] = (uint8_t)ReadPreloadedSymbol(table, br, bits, value);
+BROTLI_LOG_ARRAY_INDEX(ringbuffer, pos);
+pos++;
+copies++;
+}
+return copies;
+}
+static BROTLI_INLINE brotli_reg_t Log2Floor(brotli_reg_t x) {
+brotli_reg_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(
+brotli_reg_t alphabet_size_max, brotli_reg_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;
+brotli_reg_t max_bits = Log2Floor(alphabet_size_max - 1);
+brotli_reg_t i = h->sub_loop_counter;
+brotli_reg_t num_symbols = h->symbol;
+while (i <= num_symbols) {
+brotli_reg_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) {
+brotli_reg_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(brotli_reg_t code_len,
+brotli_reg_t* symbol, brotli_reg_t* repeat, brotli_reg_t* space,
+brotli_reg_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(brotli_reg_t code_len,
+brotli_reg_t repeat_delta, brotli_reg_t alphabet_size, brotli_reg_t* symbol,
+brotli_reg_t* repeat, brotli_reg_t* space, brotli_reg_t* prev_code_len,
+brotli_reg_t* repeat_code_len, uint16_t* symbol_lists,
+uint16_t* code_length_histo, int* next_symbol) {
+brotli_reg_t old_repeat;
+brotli_reg_t extra_bits = 3;  /* for BROTLI_REPEAT_ZERO_CODE_LENGTH */
+brotli_reg_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) {
+brotli_reg_t 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(
+brotli_reg_t alphabet_size, BrotliDecoderState* s) {
+BrotliBitReader* br = &s->br;
+BrotliMetablockHeaderArena* h = &s->arena.header;
+brotli_reg_t symbol = h->symbol;
+brotli_reg_t repeat = h->repeat;
+brotli_reg_t space = h->space;
+brotli_reg_t prev_code_len = h->prev_code_len;
+brotli_reg_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;
+brotli_reg_t code_len;
+BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(p);
+if (!BrotliCheckInputAmount(br)) {
+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 */
+brotli_reg_t extra_bits =
+(code_len == BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) ? 2 : 3;
+brotli_reg_t repeat_delta =
+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(
+brotli_reg_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;
+brotli_reg_t code_len;
+brotli_reg_t available_bits;
+brotli_reg_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 */
+brotli_reg_t extra_bits = code_len - 14U;
+brotli_reg_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;
+brotli_reg_t num_codes = h->repeat;
+brotli_reg_t space = h->space;
+brotli_reg_t i = h->sub_loop_counter;
+for (; i < BROTLI_CODE_LENGTH_CODES; ++i) {
+const uint8_t code_len_idx = kCodeLengthCodeOrder[i];
+brotli_reg_t ix;
+brotli_reg_t v;
+if (BROTLI_PREDICT_FALSE(!BrotliSafeGetBits(br, 4, &ix))) {
+brotli_reg_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(brotli_reg_t alphabet_size_max,
+brotli_reg_t alphabet_size_limit,
+HuffmanCode* table,
+brotli_reg_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: {
+brotli_reg_t table_size;
+if (h->symbol == 3) {
+brotli_reg_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,
+(uint32_t)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: {
+brotli_reg_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: {
+brotli_reg_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);  /* COV_NF_LINE */
+}
+}
+}
+/* Decodes a block length by reading 3..39 bits. */
+static BROTLI_INLINE brotli_reg_t ReadBlockLength(const HuffmanCode* table,
+BrotliBitReader* br) {
+brotli_reg_t code;
+brotli_reg_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, brotli_reg_t* result, const HuffmanCode* table,
+BrotliBitReader* br) {
+brotli_reg_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;
+}
+{
+brotli_reg_t bits;
+brotli_reg_t nbits = _kBrotliPrefixCodeRanges[index].nbits;
+brotli_reg_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, brotli_reg_t v_len, BrotliDecoderState* state) {
+/* Reinitialize elements that could have been changed. */
+brotli_reg_t i = 1;
+brotli_reg_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) {
+brotli_reg_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(brotli_reg_t context_map_size,
+brotli_reg_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: {
+brotli_reg_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: {
+brotli_reg_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: {
+brotli_reg_t context_index = h->context_index;
+brotli_reg_t max_run_length_prefix = h->max_run_length_prefix;
+uint8_t* context_map = *context_map_arg;
+brotli_reg_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. */
+{
+brotli_reg_t reps;
+if (!BrotliSafeReadBits(br, code, &reps)) {
+h->code = code;
+h->context_index = context_index;
+return BROTLI_DECODER_NEEDS_MORE_INPUT;
+}
+reps += (brotli_reg_t)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: {
+brotli_reg_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);  /* COV_NF_LINE */
+}
+}
+/* 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) {
+brotli_reg_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;
+brotli_reg_t* ringbuffer = &s->block_type_rb[tree_type * 2];
+brotli_reg_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);) {
+/* NOLINTNEXTLINE(bugprone-macro-repeated-side-effects) */
+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;
+brotli_reg_t block_type = s->block_type_rb[1];
+brotli_reg_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
+SkipMetadataBlock(BrotliDecoderState* s) {
+BrotliBitReader* br = &s->br;
+int nbytes;
+if (s->meta_block_remaining_len == 0) {
+return BROTLI_DECODER_SUCCESS;
+}
+BROTLI_DCHECK((BrotliGetAvailableBits(br) & 7) == 0);
+/* Drain accumulator. */
+if (BrotliGetAvailableBits(br) >= 8) {
+uint8_t buffer[8];
+nbytes = (int)(BrotliGetAvailableBits(br)) >> 3;
+BROTLI_DCHECK(nbytes <= 8);
+if (nbytes > s->meta_block_remaining_len) {
+nbytes = s->meta_block_remaining_len;
+}
+BrotliCopyBytes(buffer, br, (size_t)nbytes);
+if (s->metadata_chunk_func) {
+s->metadata_chunk_func(s->metadata_callback_opaque, buffer,
+(size_t)nbytes);
+}
+s->meta_block_remaining_len -= nbytes;
+if (s->meta_block_remaining_len == 0) {
+return BROTLI_DECODER_SUCCESS;
+}
+}
+/* Direct access to metadata is possible. */
+nbytes = (int)BrotliGetRemainingBytes(br);
+if (nbytes > s->meta_block_remaining_len) {
+nbytes = s->meta_block_remaining_len;
+}
+if (nbytes > 0) {
+if (s->metadata_chunk_func) {
+s->metadata_chunk_func(s->metadata_callback_opaque, br->next_in,
+(size_t)nbytes);
+}
+BrotliDropBytes(br, (size_t)nbytes);
+s->meta_block_remaining_len -= nbytes;
+if (s->meta_block_remaining_len == 0) {
+return BROTLI_DECODER_SUCCESS;
+}
+}
+BROTLI_DCHECK(BrotliGetRemainingBytes(br) == 0);
+return BROTLI_DECODER_NEEDS_MORE_INPUT;
+}
+static BrotliDecoderErrorCode BROTLI_NOINLINE CopyUncompressedBlockToOutput(
+size_t* available_out, uint8_t** next_out, size_t* total_out,
+BrotliDecoderState* s) {
+/* TODO(eustas): 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 */
+}
+static BROTLI_BOOL AttachCompoundDictionary(
+BrotliDecoderState* state, const uint8_t* data, size_t size) {
+BrotliDecoderCompoundDictionary* addon = state->compound_dictionary;
+if (state->state != BROTLI_STATE_UNINITED) return BROTLI_FALSE;
+if (!addon) {
+addon = (BrotliDecoderCompoundDictionary*)BROTLI_DECODER_ALLOC(
+state, sizeof(BrotliDecoderCompoundDictionary));
+if (!addon) return BROTLI_FALSE;
+addon->num_chunks = 0;
+addon->total_size = 0;
+addon->br_length = 0;
+addon->br_copied = 0;
+addon->block_bits = -1;
+addon->chunk_offsets[0] = 0;
+state->compound_dictionary = addon;
+}
+if (addon->num_chunks == 15) return BROTLI_FALSE;
+addon->chunks[addon->num_chunks] = data;
+addon->num_chunks++;
+addon->total_size += (int)size;
+addon->chunk_offsets[addon->num_chunks] = addon->total_size;
+return BROTLI_TRUE;
+}
+static void EnsureCoumpoundDictionaryInitialized(BrotliDecoderState* state) {
+BrotliDecoderCompoundDictionary* addon = state->compound_dictionary;
+/* 256 = (1 << 8) slots in block map. */
+int block_bits = 8;
+int cursor = 0;
+int index = 0;
+if (addon->block_bits != -1) return;
+while (((addon->total_size - 1) >> block_bits) != 0) block_bits++;
+block_bits -= 8;
+addon->block_bits = block_bits;
+while (cursor < addon->total_size) {
+while (addon->chunk_offsets[index + 1] < cursor) index++;
+addon->block_map[cursor >> block_bits] = (uint8_t)index;
+cursor += 1 << block_bits;
+}
+}
+static BROTLI_BOOL InitializeCompoundDictionaryCopy(BrotliDecoderState* s,
+int address, int length) {
+BrotliDecoderCompoundDictionary* addon = s->compound_dictionary;
+int index;
+EnsureCoumpoundDictionaryInitialized(s);
+index = addon->block_map[address >> addon->block_bits];
+while (address >= addon->chunk_offsets[index + 1]) index++;
+if (addon->total_size < address + length) return BROTLI_FALSE;
+/* 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 -= length;
+addon->br_index = index;
+addon->br_offset = address - addon->chunk_offsets[index];
+addon->br_length = length;
+addon->br_copied = 0;
+return BROTLI_TRUE;
+}
+static int GetCompoundDictionarySize(BrotliDecoderState* s) {
+return s->compound_dictionary ? s->compound_dictionary->total_size : 0;
+}
+static int CopyFromCompoundDictionary(BrotliDecoderState* s, int pos) {
+BrotliDecoderCompoundDictionary* addon = s->compound_dictionary;
+int orig_pos = pos;
+while (addon->br_length != addon->br_copied) {
+uint8_t* copy_dst = &s->ringbuffer[pos];
+const uint8_t* copy_src =
+addon->chunks[addon->br_index] + addon->br_offset;
+int space = s->ringbuffer_size - pos;
+int rem_chunk_length = (addon->chunk_offsets[addon->br_index + 1] -
+addon->chunk_offsets[addon->br_index]) - addon->br_offset;
+int length = addon->br_length - addon->br_copied;
+if (length > rem_chunk_length) length = rem_chunk_length;
+if (length > space) length = space;
+memcpy(copy_dst, copy_src, (size_t)length);
+pos += length;
+addon->br_offset += length;
+addon->br_copied += length;
+if (length == rem_chunk_length) {
+addon->br_index++;
+addon->br_offset = 0;
+}
+if (pos == s->ringbuffer_size) break;
+}
+return pos - orig_pos;
+}
+BROTLI_BOOL BrotliDecoderAttachDictionary(
+BrotliDecoderState* state, BrotliSharedDictionaryType type,
+size_t data_size, const uint8_t data[BROTLI_ARRAY_PARAM(data_size)]) {
+brotli_reg_t i;
+brotli_reg_t num_prefix_before = state->dictionary->num_prefix;
+if (state->state != BROTLI_STATE_UNINITED) return BROTLI_FALSE;
+if (!BrotliSharedDictionaryAttach(state->dictionary, type, data_size, data)) {
+return BROTLI_FALSE;
+}
+for (i = num_prefix_before; i < state->dictionary->num_prefix; i++) {
+if (!AttachCompoundDictionary(
+state, state->dictionary->prefix[i],
+state->dictionary->prefix_size[i])) {
+return BROTLI_FALSE;
+}
+}
+return BROTLI_TRUE;
+}
+/* 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]) {
+brotli_reg_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, brotli_reg_t n_bits, brotli_reg_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, brotli_reg_t n_bits, brotli_reg_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;
+brotli_reg_t npostfix = s->distance_postfix_bits;
+brotli_reg_t ndirect = s->num_direct_distance_codes;
+brotli_reg_t alphabet_size_limit = s->distance_hgroup.alphabet_size_limit;
+brotli_reg_t postfix = (brotli_reg_t)1u << npostfix;
+brotli_reg_t j;
+brotli_reg_t bits = 1;
+brotli_reg_t half = 0;
+/* Skip short codes. */
+brotli_reg_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) {
+brotli_reg_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;
+brotli_reg_t code;
+brotli_reg_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) {
+brotli_reg_t cmd_code;
+brotli_reg_t insert_len_extra = 0;
+brotli_reg_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) {
+if (safe) {
+return BROTLI_TRUE;
+}
+return BrotliCheckInputAmount(br);
+}
+#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;
+int compound_dictionary_size = GetCompoundDictionarySize(s);
+if (!CheckInputAmount(safe, br)) {
+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);  /* COV_NF_LINE */
+}
+CommandBegin:
+if (safe) {
+s->state = BROTLI_STATE_COMMAND_BEGIN;
+}
+if (!CheckInputAmount(safe, br)) {
+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) {
+brotli_reg_t bits;
+brotli_reg_t value;
+PreloadSymbol(safe, s->literal_htree, br, &bits, &value);
+if (!safe) {
+// This is a hottest part of the decode, so we copy the loop below
+// and optimize it by calculating the number of steps where all checks
+// evaluate to false (ringbuffer size/block size/input size).
+// Since all checks are loop invariant, we just need to find
+// minimal number of iterations for a simple loop, and run
+// the full version for the remainder.
+int num_steps = i - 1;
+if (num_steps > 0 && ((brotli_reg_t)(num_steps) > s->block_length[0])) {
+// Safe cast, since block_length < steps
+num_steps = (int)s->block_length[0];
+}
+if (s->ringbuffer_size >= pos &&
+(s->ringbuffer_size - pos) <= num_steps) {
+num_steps = s->ringbuffer_size - pos - 1;
+}
+if (num_steps < 0) {
+num_steps = 0;
+}
+num_steps = BrotliCopyPreloadedSymbolsToU8(s->literal_htree, br, &bits,
+&value, s->ringbuffer, pos,
+num_steps);
+pos += num_steps;
+s->block_length[0] -= (brotli_reg_t)num_steps;
+i -= num_steps;
+do {
+if (!CheckInputAmount(safe, br)) {
+s->state = BROTLI_STATE_COMMAND_INNER;
+result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+goto saveStateAndReturn;
+}
+if (BROTLI_PREDICT_FALSE(s->block_length[0] == 0)) {
+goto NextLiteralBlock;
+}
+BrotliCopyPreloadedSymbolsToU8(s->literal_htree, br, &bits, &value,
+s->ringbuffer, pos, 1);
+--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 { /* safe */
+do {
+if (BROTLI_PREDICT_FALSE(s->block_length[0] == 0)) {
+goto NextLiteralBlock;
+}
+brotli_reg_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)) {
+s->state = BROTLI_STATE_COMMAND_INNER;
+result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+goto saveStateAndReturn;
+}
+if (BROTLI_PREDICT_FALSE(s->block_length[0] == 0)) {
+goto NextLiteralBlock;
+}
+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 {
+brotli_reg_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 (s->distance_code - s->max_distance - 1 < compound_dictionary_size) {
+int address = compound_dictionary_size -
+(s->distance_code - s->max_distance);
+if (!InitializeCompoundDictionaryCopy(s, address, i)) {
+return BROTLI_FAILURE(BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY);
+}
+pos += CopyFromCompoundDictionary(s, pos);
+if (pos >= s->ringbuffer_size) {
+s->state = BROTLI_STATE_COMMAND_POST_WRITE_1;
+goto saveStateAndReturn;
+}
+} else if (i >= SHARED_BROTLI_MIN_DICTIONARY_WORD_LENGTH &&
+i <= SHARED_BROTLI_MAX_DICTIONARY_WORD_LENGTH) {
+uint8_t p1 = s->ringbuffer[(pos - 1) & s->ringbuffer_mask];
+uint8_t p2 = s->ringbuffer[(pos - 2) & s->ringbuffer_mask];
+uint8_t dict_id = s->dictionary->context_based ?
+s->dictionary->context_map[BROTLI_CONTEXT(p1, p2, s->context_lookup)]
+: 0;
+const BrotliDictionary* words = s->dictionary->words[dict_id];
+const BrotliTransforms* transforms = s->dictionary->transforms[dict_id];
+int offset = (int)words->offsets_by_length[i];
+brotli_reg_t shift = words->size_bits_by_length[i];
+int address =
+s->distance_code - s->max_distance - 1 - compound_dictionary_size;
+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 the distance is out of bound, select a next static dictionary if
+there exist multiple. */
+if ((transform_idx >= (int)transforms->num_transforms ||
+words->size_bits_by_length[i] == 0) &&
+s->dictionary->num_dictionaries > 1) {
+uint8_t dict_id2;
+int dist_remaining = address -
+(int)(((1u << shift) & ~1u)) * (int)transforms->num_transforms;
+for (dict_id2 = 0; dict_id2 < s->dictionary->num_dictionaries;
+dict_id2++) {
+const BrotliDictionary* words2 = s->dictionary->words[dict_id2];
+if (dict_id2 != dict_id && words2->size_bits_by_length[i] != 0) {
+const BrotliTransforms* transforms2 =
+s->dictionary->transforms[dict_id2];
+brotli_reg_t shift2 = words2->size_bits_by_length[i];
+int num = (int)((1u << shift2) & ~1u) *
+(int)transforms2->num_transforms;
+if (dist_remaining < num) {
+dict_id = dict_id2;
+words = words2;
+transforms = transforms2;
+address = dist_remaining;
+shift = shift2;
+mask = (int)BitMask(shift);
+word_idx = address & mask;
+transform_idx = address >> shift;
+offset = (int)words->offsets_by_length[i] + word_idx * i;
+break;
+}
+dist_remaining -= num;
+}
+}
+}
+if (BROTLI_PREDICT_FALSE(words->size_bits_by_length[i] == 0)) {
+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);
+}
+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]));
+if (len == 0 && s->distance_code <= 120) {
+BROTLI_LOG(("Invalid length-0 dictionary word after transform\n"));
+return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_TRANSFORM);
+}
+}
+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;
+}
+NextLiteralBlock:
+BROTLI_SAFE(DecodeLiteralBlockSwitch(s));
+goto CommandInner;
+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[BROTLI_ARRAY_PARAM(encoded_size)],
+size_t* decoded_size,
+uint8_t decoded_buffer[BROTLI_ARRAY_PARAM(*decoded_size)]) {
+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;
+size_t input_size = *available_in;
+#define BROTLI_SAVE_ERROR_CODE(code) \
+SaveErrorCode(s, (code), input_size - *available_in)
+/* 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 BROTLI_SAVE_ERROR_CODE(
+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. */
+BrotliBitReaderSetInput(br, *next_in, *available_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;
+BrotliBitReaderSetInput(br, &s->buffer.u8[0], s->buffer_length);
+}
+/* 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->next_in == br->last_in) {
+/* 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;
+BrotliBitReaderSetInput(br, *next_in, *available_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;
+BROTLI_DCHECK(s->buffer_length < 8);
+s->buffer.u8[s->buffer_length] = **next_in;
+s->buffer_length++;
+BrotliBitReaderSetInput(br, &s->buffer.u8[0], 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 = BrotliBitReaderGetAvailIn(br);
+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 = BrotliBitReaderGetAvailIn(br);
+*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: {
+brotli_reg_t bits;
+if (!BrotliSafeReadBits(br, 6, &bits)) {
+result = BROTLI_DECODER_NEEDS_MORE_INPUT;
+break;
+}
+s->window_bits = bits & 63u;
+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;
+if (s->metadata_start_func) {
+s->metadata_start_func(s->metadata_callback_opaque,
+(size_t)s->meta_block_remaining_len);
+}
+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: {
+brotli_reg_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: {
+brotli_reg_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:
+result = SkipMetadataBlock(s);
+if (result != BROTLI_DECODER_SUCCESS) {
+break;
+}
+s->state = BROTLI_STATE_METABLOCK_DONE;
+break;
+case BROTLI_STATE_METABLOCK_HEADER_2: {
+brotli_reg_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: {
+brotli_reg_t npostfix = s->distance_postfix_bits;
+brotli_reg_t ndirect = s->num_direct_distance_codes;
+brotli_reg_t distance_alphabet_size_max = BROTLI_DISTANCE_ALPHABET_SIZE(
+npostfix, ndirect, BROTLI_MAX_DISTANCE_BITS);
+brotli_reg_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, (uint32_t)npostfix,
+(uint32_t)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 BROTLI_SAVE_ERROR_CODE(
+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 BROTLI_SAVE_ERROR_CODE(BROTLI_FAILURE(
+BROTLI_DECODER_ERROR_UNREACHABLE));  /* COV_NF_LINE */
+}
+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) {
+BrotliDecoderCompoundDictionary* addon = s->compound_dictionary;
+if (addon && (addon->br_length != addon->br_copied)) {
+s->pos += CopyFromCompoundDictionary(s, s->pos);
+if (s->pos >= s->ringbuffer_size) continue;
+}
+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 = BrotliBitReaderGetAvailIn(br);
+*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 BROTLI_SAVE_ERROR_CODE(result);
+}
+}
+return BROTLI_SAVE_ERROR_CODE(result);
+#undef BROTLI_SAVE_ERROR_CODE
+}
+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, 0);
+*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 #PREFIX #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(void) {
+return BROTLI_VERSION;
+}
+void BrotliDecoderSetMetadataCallbacks(
+BrotliDecoderState* state,
+brotli_decoder_metadata_start_func start_func,
+brotli_decoder_metadata_chunk_func chunk_func, void* opaque) {
+state->metadata_start_func = start_func;
+state->metadata_chunk_func = chunk_func;
+state->metadata_callback_opaque = opaque;
+}
+/* Escalate internal functions visibility; for testing purposes only. */
+#if defined(BROTLI_TEST)
+BROTLI_BOOL SafeReadSymbolForTest(
+const HuffmanCode*, BrotliBitReader*, brotli_reg_t*);
+BROTLI_BOOL SafeReadSymbolForTest(
+const HuffmanCode* table, BrotliBitReader* br, brotli_reg_t* result) {
+return SafeReadSymbol(table, br, result);
+}
+void InverseMoveToFrontTransformForTest(
+uint8_t*, brotli_reg_t, BrotliDecoderState*);
+void InverseMoveToFrontTransformForTest(
+uint8_t* v, brotli_reg_t l, BrotliDecoderState* s) {
+InverseMoveToFrontTransform(v, l, s);
+}
+#endif
+#if defined(__cplusplus) || defined(c_plusplus)
+}  /* extern "C" */
+#endif

Mercurial > hgrepos > Python2 > PyMuPDF

comparison mupdf-source/thirdparty/brotli/c/dec/decode.c @ 2:b50eed0cc0ef upstream