| // Copyright 2013 Google Inc. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include "./bit_reader.h" |
| #include "./context.h" |
| #include "./decode.h" |
| #include "./huffman.h" |
| #include "./prefix.h" |
| #include "./safe_malloc.h" |
| |
| #if defined(__cplusplus) || defined(c_plusplus) |
| extern "C" { |
| #endif |
| |
| #ifdef BROTLI_DECODE_DEBUG |
| #define BROTLI_LOG_UINT(name) \ |
| printf("[%s] %s = %lu\n", __func__, #name, (unsigned long)(name)) |
| #define BROTLI_LOG_ARRAY_INDEX(array_name, idx) \ |
| printf("[%s] %s[%lu] = %lu\n", __func__, #array_name, \ |
| (unsigned long)(idx), (unsigned long)array_name[idx]) |
| #else |
| #define BROTLI_LOG_UINT(name) |
| #define BROTLI_LOG_ARRAY_INDEX(array_name, idx) |
| #endif |
| |
| static const int kDefaultCodeLength = 8; |
| static const int kCodeLengthRepeatCode = 16; |
| static const int kNumLiteralCodes = 256; |
| static const int kNumInsertAndCopyCodes = 704; |
| static const int kNumBlockLengthCodes = 26; |
| static const int kLiteralContextBits = 6; |
| static const int kDistanceContextBits = 2; |
| |
| #define CODE_LENGTH_CODES 18 |
| static const uint8_t kCodeLengthCodeOrder[CODE_LENGTH_CODES] = { |
| 1, 2, 3, 4, 0, 17, 5, 6, 16, 7, 8, 9, 10, 11, 12, 13, 14, 15, |
| }; |
| |
| #define NUM_DISTANCE_SHORT_CODES 16 |
| static const int kDistanceShortCodeIndexOffset[NUM_DISTANCE_SHORT_CODES] = { |
| 3, 2, 1, 0, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2 |
| }; |
| |
| static const int kDistanceShortCodeValueOffset[NUM_DISTANCE_SHORT_CODES] = { |
| 0, 0, 0, 0, -1, 1, -2, 2, -3, 3, -1, 1, -2, 2, -3, 3 |
| }; |
| |
| static BROTLI_INLINE int DecodeWindowBits(BrotliBitReader* br) { |
| if (BrotliReadBits(br, 1)) { |
| return 17 + BrotliReadBits(br, 3); |
| } else { |
| return 16; |
| } |
| } |
| |
| // Decodes a number in the range [0..255], by reading 1 - 11 bits. |
| static BROTLI_INLINE int DecodeVarLenUint8(BrotliBitReader* br) { |
| if (BrotliReadBits(br, 1)) { |
| int nbits = BrotliReadBits(br, 3); |
| if (nbits == 0) { |
| return 1; |
| } else { |
| return BrotliReadBits(br, nbits) + (1 << nbits); |
| } |
| } |
| return 0; |
| } |
| |
| static void DecodeMetaBlockLength(BrotliBitReader* br, |
| size_t* meta_block_length, |
| int* input_end, |
| int* is_uncompressed) { |
| int size_nibbles; |
| int i; |
| *input_end = BrotliReadBits(br, 1); |
| *meta_block_length = 0; |
| *is_uncompressed = 0; |
| if (*input_end && BrotliReadBits(br, 1)) { |
| return; |
| } |
| size_nibbles = BrotliReadBits(br, 2) + 4; |
| for (i = 0; i < size_nibbles; ++i) { |
| *meta_block_length |= BrotliReadBits(br, 4) << (i * 4); |
| } |
| ++(*meta_block_length); |
| if (!*input_end) { |
| *is_uncompressed = BrotliReadBits(br, 1); |
| } |
| } |
| |
| // Decodes the next Huffman code from bit-stream. |
| static BROTLI_INLINE int ReadSymbol(const HuffmanTree* tree, |
| BrotliBitReader* br) { |
| uint32_t bits; |
| int bitpos; |
| int lut_ix; |
| int lut_bits; |
| const HuffmanTreeNode* node = tree->root_; |
| BrotliFillBitWindow(br); |
| bits = BrotliPrefetchBits(br); |
| bitpos = br->bit_pos_; |
| // Check if we find the bit combination from the Huffman lookup table. |
| lut_ix = bits & (HUFF_LUT - 1); |
| lut_bits = tree->lut_bits_[lut_ix]; |
| if (lut_bits <= HUFF_LUT_BITS) { |
| BrotliSetBitPos(br, bitpos + lut_bits); |
| return tree->lut_symbol_[lut_ix]; |
| } |
| node += tree->lut_jump_[lut_ix]; |
| bitpos += HUFF_LUT_BITS; |
| bits >>= HUFF_LUT_BITS; |
| |
| // Decode the value from a binary tree. |
| assert(node != NULL); |
| do { |
| node = HuffmanTreeNextNode(node, bits & 1); |
| bits >>= 1; |
| ++bitpos; |
| } while (HuffmanTreeNodeIsNotLeaf(node)); |
| BrotliSetBitPos(br, bitpos); |
| return node->symbol_; |
| } |
| |
| static void PrintUcharVector(const uint8_t* v, int len) { |
| while (len-- > 0) printf(" %d", *v++); |
| printf("\n"); |
| } |
| |
| static int ReadHuffmanCodeLengths( |
| const uint8_t* code_length_code_lengths, |
| int num_symbols, uint8_t* code_lengths, |
| BrotliBitReader* br) { |
| int ok = 0; |
| int symbol; |
| int max_symbol; |
| int decode_number_of_code_length_codes; |
| int prev_code_len = kDefaultCodeLength; |
| int repeat = 0; |
| int repeat_length = 0; |
| HuffmanTree tree; |
| |
| if (!BrotliHuffmanTreeBuildImplicit(&tree, code_length_code_lengths, |
| CODE_LENGTH_CODES)) { |
| printf("[ReadHuffmanCodeLengths] Building code length tree failed: "); |
| PrintUcharVector(code_length_code_lengths, CODE_LENGTH_CODES); |
| return 0; |
| } |
| |
| if (!BrotliReadMoreInput(br)) { |
| printf("[ReadHuffmanCodeLengths] Unexpected end of input.\n"); |
| return 0; |
| } |
| decode_number_of_code_length_codes = BrotliReadBits(br, 1); |
| BROTLI_LOG_UINT(decode_number_of_code_length_codes); |
| if (decode_number_of_code_length_codes) { |
| if (BrotliReadBits(br, 1)) { |
| max_symbol = 68 + BrotliReadBits(br, 7); |
| } else { |
| max_symbol = 4 + BrotliReadBits(br, 6); |
| } |
| if (max_symbol > num_symbols) { |
| printf("[ReadHuffmanCodeLengths] max_symbol > num_symbols (%d vs %d)\n", |
| max_symbol, num_symbols); |
| goto End; |
| } |
| } else { |
| max_symbol = num_symbols; |
| } |
| BROTLI_LOG_UINT(max_symbol); |
| |
| symbol = 0; |
| while (symbol + repeat < num_symbols) { |
| int code_len; |
| if (max_symbol-- == 0) break; |
| if (!BrotliReadMoreInput(br)) { |
| printf("[ReadHuffmanCodeLengths] Unexpected end of input.\n"); |
| goto End; |
| } |
| code_len = ReadSymbol(&tree, br); |
| BROTLI_LOG_UINT(symbol); |
| BROTLI_LOG_UINT(repeat); |
| BROTLI_LOG_UINT(repeat_length); |
| BROTLI_LOG_UINT(code_len); |
| if ((code_len < kCodeLengthRepeatCode) || |
| (code_len == kCodeLengthRepeatCode && repeat_length == 0) || |
| (code_len > kCodeLengthRepeatCode && repeat_length > 0)) { |
| while (repeat > 0) { |
| code_lengths[symbol++] = repeat_length; |
| --repeat; |
| } |
| } |
| if (code_len < kCodeLengthRepeatCode) { |
| code_lengths[symbol++] = code_len; |
| if (code_len != 0) prev_code_len = code_len; |
| } else { |
| const int extra_bits = code_len - 14; |
| if (repeat > 0) { |
| repeat -= 2; |
| repeat <<= extra_bits; |
| } |
| repeat += BrotliReadBits(br, extra_bits) + 3; |
| repeat_length = (code_len == kCodeLengthRepeatCode ? prev_code_len : 0); |
| } |
| } |
| if (symbol + repeat > num_symbols) { |
| printf("[ReadHuffmanCodeLengths] symbol + repeat > num_symbols " |
| "(%d + %d vs %d)\n", symbol, repeat, num_symbols); |
| goto End; |
| } |
| while (repeat-- > 0) code_lengths[symbol++] = repeat_length; |
| while (symbol < num_symbols) code_lengths[symbol++] = 0; |
| ok = 1; |
| |
| End: |
| BrotliHuffmanTreeRelease(&tree); |
| return ok; |
| } |
| |
| static int ReadHuffmanCode(int alphabet_size, |
| HuffmanTree* tree, |
| BrotliBitReader* br) { |
| int ok = 1; |
| int simple_code; |
| uint8_t* code_lengths = NULL; |
| |
| code_lengths = |
| (uint8_t*)BrotliSafeMalloc((uint64_t)alphabet_size, |
| sizeof(*code_lengths)); |
| if (code_lengths == NULL) { |
| return 0; |
| } |
| if (!BrotliReadMoreInput(br)) { |
| printf("[ReadHuffmanCode] Unexpected end of input.\n"); |
| return 0; |
| } |
| simple_code = BrotliReadBits(br, 1); |
| BROTLI_LOG_UINT(simple_code); |
| if (simple_code) { // Read symbols, codes & code lengths directly. |
| int i; |
| int max_bits_counter = alphabet_size - 1; |
| int max_bits = 0; |
| int symbols[4] = { 0 }; |
| const int num_symbols = BrotliReadBits(br, 2) + 1; |
| while (max_bits_counter) { |
| max_bits_counter >>= 1; |
| ++max_bits; |
| } |
| memset(code_lengths, 0, alphabet_size); |
| for (i = 0; i < num_symbols; ++i) { |
| symbols[i] = BrotliReadBits(br, max_bits); |
| code_lengths[symbols[i]] = 2; |
| } |
| code_lengths[symbols[0]] = 1; |
| switch (num_symbols) { |
| case 1: |
| case 3: |
| break; |
| case 2: |
| code_lengths[symbols[1]] = 1; |
| break; |
| case 4: |
| if (BrotliReadBits(br, 1)) { |
| code_lengths[symbols[2]] = 3; |
| code_lengths[symbols[3]] = 3; |
| } else { |
| code_lengths[symbols[0]] = 2; |
| } |
| break; |
| } |
| BROTLI_LOG_UINT(num_symbols); |
| } else { // Decode Huffman-coded code lengths. |
| int i; |
| uint8_t code_length_code_lengths[CODE_LENGTH_CODES] = { 0 }; |
| const int num_codes = BrotliReadBits(br, 4) + 3; |
| BROTLI_LOG_UINT(num_codes); |
| if (num_codes > CODE_LENGTH_CODES) { |
| return 0; |
| } |
| for (i = BrotliReadBits(br, 1) * 2; i < num_codes; ++i) { |
| int code_len_idx = kCodeLengthCodeOrder[i]; |
| int v = BrotliReadBits(br, 2); |
| if (v == 1) { |
| v = BrotliReadBits(br, 1); |
| if (v == 0) { |
| v = 2; |
| } else { |
| v = BrotliReadBits(br, 1); |
| if (v == 0) { |
| v = 1; |
| } else { |
| v = 5; |
| } |
| } |
| } else if (v == 2) { |
| v = 4; |
| } |
| code_length_code_lengths[code_len_idx] = v; |
| BROTLI_LOG_ARRAY_INDEX(code_length_code_lengths, code_len_idx); |
| } |
| ok = ReadHuffmanCodeLengths(code_length_code_lengths, alphabet_size, |
| code_lengths, br); |
| } |
| if (ok) { |
| ok = BrotliHuffmanTreeBuildImplicit(tree, code_lengths, alphabet_size); |
| if (!ok) { |
| printf("[ReadHuffmanCode] HuffmanTreeBuildImplicit failed: "); |
| PrintUcharVector(code_lengths, alphabet_size); |
| } |
| } |
| free(code_lengths); |
| return ok; |
| } |
| |
| static int ReadCopyDistance(const HuffmanTree* tree, |
| int num_direct_codes, |
| int postfix_bits, |
| uint32_t postfix_mask, |
| BrotliBitReader* br) { |
| int code; |
| int nbits; |
| int postfix; |
| int offset; |
| code = ReadSymbol(tree, br); |
| if (code < num_direct_codes) { |
| return code; |
| } |
| code -= num_direct_codes; |
| postfix = code & postfix_mask; |
| code >>= postfix_bits; |
| nbits = (code >> 1) + 1; |
| offset = ((2 + (code & 1)) << nbits) - 4; |
| return (num_direct_codes + |
| ((offset + BrotliReadBits(br, nbits)) << postfix_bits) + |
| postfix); |
| } |
| |
| static int ReadBlockLength(const HuffmanTree* tree, BrotliBitReader* br) { |
| int code; |
| int nbits; |
| code = ReadSymbol(tree, br); |
| nbits = kBlockLengthPrefixCode[code].nbits; |
| return kBlockLengthPrefixCode[code].offset + BrotliReadBits(br, nbits); |
| } |
| |
| static void ReadInsertAndCopy(const HuffmanTree* tree, |
| int* insert_len, |
| int* copy_len, |
| int* copy_dist, |
| BrotliBitReader* br) { |
| int code; |
| int range_idx; |
| int insert_code; |
| int insert_extra_bits; |
| int copy_code; |
| int copy_extra_bits; |
| code = ReadSymbol(tree, br); |
| range_idx = code >> 6; |
| if (range_idx >= 2) { |
| range_idx -= 2; |
| *copy_dist = -1; |
| } else { |
| *copy_dist = 0; |
| } |
| insert_code = kInsertRangeLut[range_idx] + ((code >> 3) & 7); |
| copy_code = kCopyRangeLut[range_idx] + (code & 7); |
| *insert_len = kInsertLengthPrefixCode[insert_code].offset; |
| insert_extra_bits = kInsertLengthPrefixCode[insert_code].nbits; |
| if (insert_extra_bits > 0) { |
| *insert_len += BrotliReadBits(br, insert_extra_bits); |
| } |
| *copy_len = kCopyLengthPrefixCode[copy_code].offset; |
| copy_extra_bits = kCopyLengthPrefixCode[copy_code].nbits; |
| if (copy_extra_bits > 0) { |
| *copy_len += BrotliReadBits(br, copy_extra_bits); |
| } |
| } |
| |
| static int TranslateShortCodes(int code, int* ringbuffer, size_t index) { |
| int val; |
| if (code < NUM_DISTANCE_SHORT_CODES) { |
| index += kDistanceShortCodeIndexOffset[code]; |
| index &= 3; |
| val = ringbuffer[index] + kDistanceShortCodeValueOffset[code]; |
| } else { |
| val = code - NUM_DISTANCE_SHORT_CODES + 1; |
| } |
| return val; |
| } |
| |
| static void MoveToFront(uint8_t* v, uint8_t index) { |
| uint8_t value = v[index]; |
| uint8_t i = index; |
| for (; i; --i) v[i] = v[i - 1]; |
| v[0] = value; |
| } |
| |
| static void InverseMoveToFrontTransform(uint8_t* v, int v_len) { |
| uint8_t mtf[256]; |
| int i; |
| for (i = 0; i < 256; ++i) { |
| mtf[i] = i; |
| } |
| for (i = 0; i < v_len; ++i) { |
| uint8_t index = v[i]; |
| v[i] = mtf[index]; |
| if (index) MoveToFront(mtf, index); |
| } |
| } |
| |
| // Contains a collection of huffman trees with the same alphabet size. |
| typedef struct { |
| int alphabet_size; |
| int num_htrees; |
| HuffmanTree* htrees; |
| } HuffmanTreeGroup; |
| |
| static void HuffmanTreeGroupInit(HuffmanTreeGroup* group, int alphabet_size, |
| int ntrees) { |
| group->alphabet_size = alphabet_size; |
| group->num_htrees = ntrees; |
| group->htrees = (HuffmanTree*)malloc(sizeof(HuffmanTree) * ntrees); |
| } |
| |
| static void HuffmanTreeGroupRelease(HuffmanTreeGroup* group) { |
| int i; |
| for (i = 0; i < group->num_htrees; ++i) { |
| BrotliHuffmanTreeRelease(&group->htrees[i]); |
| } |
| free(group->htrees); |
| } |
| |
| static int HuffmanTreeGroupDecode(HuffmanTreeGroup* group, |
| BrotliBitReader* br) { |
| int i; |
| for (i = 0; i < group->num_htrees; ++i) { |
| if (!ReadHuffmanCode(group->alphabet_size, &group->htrees[i], br)) { |
| return 0; |
| } |
| } |
| return 1; |
| } |
| |
| static int DecodeContextMap(int context_map_size, |
| int* num_htrees, |
| uint8_t** context_map, |
| BrotliBitReader* br) { |
| int ok = 1; |
| if (!BrotliReadMoreInput(br)) { |
| printf("[DecodeContextMap] Unexpected end of input.\n"); |
| return 0; |
| } |
| *num_htrees = DecodeVarLenUint8(br) + 1; |
| |
| BROTLI_LOG_UINT(context_map_size); |
| BROTLI_LOG_UINT(*num_htrees); |
| |
| *context_map = (uint8_t*)malloc(context_map_size); |
| if (*num_htrees <= 1) { |
| memset(*context_map, 0, context_map_size); |
| return 1; |
| } |
| |
| { |
| HuffmanTree tree_index_htree; |
| int use_rle_for_zeros = BrotliReadBits(br, 1); |
| int max_run_length_prefix = 0; |
| int i; |
| if (use_rle_for_zeros) { |
| max_run_length_prefix = BrotliReadBits(br, 4) + 1; |
| } |
| if (!ReadHuffmanCode(*num_htrees + max_run_length_prefix, |
| &tree_index_htree, br)) { |
| return 0; |
| } |
| for (i = 0; i < context_map_size;) { |
| int code; |
| if (!BrotliReadMoreInput(br)) { |
| printf("[DecodeContextMap] Unexpected end of input.\n"); |
| ok = 0; |
| goto End; |
| } |
| code = ReadSymbol(&tree_index_htree, br); |
| if (code == 0) { |
| (*context_map)[i] = 0; |
| ++i; |
| } else if (code <= max_run_length_prefix) { |
| int reps = 1 + (1 << code) + BrotliReadBits(br, code); |
| while (--reps) { |
| (*context_map)[i] = 0; |
| ++i; |
| } |
| } else { |
| (*context_map)[i] = code - max_run_length_prefix; |
| ++i; |
| } |
| } |
| End: |
| BrotliHuffmanTreeRelease(&tree_index_htree); |
| } |
| if (BrotliReadBits(br, 1)) { |
| InverseMoveToFrontTransform(*context_map, context_map_size); |
| } |
| return ok; |
| } |
| |
| static BROTLI_INLINE void DecodeBlockType(const HuffmanTree* trees, |
| int tree_type, |
| int* block_types, |
| int* ringbuffers, |
| size_t* indexes, |
| BrotliBitReader* br) { |
| int* ringbuffer = ringbuffers + tree_type * 2; |
| size_t* index = indexes + tree_type; |
| int type_code = ReadSymbol(trees + tree_type, br); |
| int block_type; |
| if (type_code == 0) { |
| block_type = ringbuffer[*index & 1]; |
| } else if (type_code == 1) { |
| block_type = ringbuffer[(*index - 1) & 1] + 1; |
| } else { |
| block_type = type_code - 2; |
| } |
| block_types[tree_type] = block_type; |
| ringbuffer[(*index) & 1] = block_type; |
| ++(*index); |
| } |
| |
| // Copy len bytes from src to dst. It can write up to ten extra bytes |
| // after the end of the copy. |
| // |
| // The main part of this loop is a simple copy of eight bytes at a time until |
| // we've copied (at least) the requested amount of bytes. However, if dst and |
| // src are less than eight bytes apart (indicating a repeating pattern of |
| // length < 8), we first need to expand the pattern in order to get the correct |
| // results. For instance, if the buffer looks like this, with the eight-byte |
| // <src> and <dst> patterns marked as intervals: |
| // |
| // abxxxxxxxxxxxx |
| // [------] src |
| // [------] dst |
| // |
| // a single eight-byte copy from <src> to <dst> will repeat the pattern once, |
| // after which we can move <dst> two bytes without moving <src>: |
| // |
| // ababxxxxxxxxxx |
| // [------] src |
| // [------] dst |
| // |
| // and repeat the exercise until the two no longer overlap. |
| // |
| // This allows us to do very well in the special case of one single byte |
| // repeated many times, without taking a big hit for more general cases. |
| // |
| // The worst case of extra writing past the end of the match occurs when |
| // dst - src == 1 and len == 1; the last copy will read from byte positions |
| // [0..7] and write to [4..11], whereas it was only supposed to write to |
| // position 1. Thus, ten excess bytes. |
| static BROTLI_INLINE void IncrementalCopyFastPath( |
| uint8_t* dst, const uint8_t* src, int len) { |
| if (src < dst) { |
| while (dst - src < 8) { |
| UNALIGNED_COPY64(dst, src); |
| len -= dst - src; |
| dst += dst - src; |
| } |
| } |
| while (len > 0) { |
| UNALIGNED_COPY64(dst, src); |
| src += 8; |
| dst += 8; |
| len -= 8; |
| } |
| } |
| |
| int BrotliDecompressedSize(size_t encoded_size, |
| const uint8_t* encoded_buffer, |
| size_t* decoded_size) { |
| BrotliMemInput memin; |
| BrotliInput input = BrotliInitMemInput(encoded_buffer, encoded_size, &memin); |
| BrotliBitReader br; |
| size_t meta_block_len; |
| int input_end; |
| int is_uncompressed; |
| if (!BrotliInitBitReader(&br, input)) { |
| return 0; |
| } |
| DecodeWindowBits(&br); |
| DecodeMetaBlockLength(&br, &meta_block_len, &input_end, &is_uncompressed); |
| if (!input_end) { |
| return 0; |
| } |
| *decoded_size = meta_block_len; |
| return 1; |
| } |
| |
| int BrotliDecompressBuffer(size_t encoded_size, |
| const uint8_t* encoded_buffer, |
| size_t* decoded_size, |
| uint8_t* decoded_buffer) { |
| BrotliMemInput memin; |
| BrotliInput in = BrotliInitMemInput(encoded_buffer, encoded_size, &memin); |
| BrotliMemOutput mout; |
| BrotliOutput out = BrotliInitMemOutput(decoded_buffer, *decoded_size, &mout); |
| int success = BrotliDecompress(in, out); |
| *decoded_size = mout.pos; |
| return success; |
| } |
| |
| int BrotliDecompress(BrotliInput input, BrotliOutput output) { |
| int ok = 1; |
| int i; |
| size_t pos = 0; |
| int input_end = 0; |
| int window_bits = 0; |
| size_t max_backward_distance; |
| size_t ringbuffer_size; |
| size_t ringbuffer_mask; |
| uint8_t* ringbuffer; |
| uint8_t* ringbuffer_end; |
| // This ring buffer holds a few past copy distances that will be used by |
| // some special distance codes. |
| int dist_rb[4] = { 16, 15, 11, 4 }; |
| size_t dist_rb_idx = 0; |
| // The previous 2 bytes used for context. |
| uint8_t prev_byte1 = 0; |
| uint8_t prev_byte2 = 0; |
| HuffmanTreeGroup hgroup[3]; |
| BrotliBitReader br; |
| |
| static const int kRingBufferWriteAheadSlack = 16; |
| |
| static const int kMaxDictionaryWordLength = 0; |
| |
| if (!BrotliInitBitReader(&br, input)) { |
| return 0; |
| } |
| |
| // Decode window size. |
| window_bits = DecodeWindowBits(&br); |
| max_backward_distance = (1ULL << window_bits) - 16; |
| |
| ringbuffer_size = 1ULL << window_bits; |
| ringbuffer_mask = ringbuffer_size - 1; |
| ringbuffer = (uint8_t*)malloc(ringbuffer_size + |
| kRingBufferWriteAheadSlack + |
| kMaxDictionaryWordLength); |
| ringbuffer_end = ringbuffer + ringbuffer_size; |
| |
| while (!input_end && ok) { |
| size_t meta_block_len = 0; |
| size_t meta_block_end_pos; |
| int is_uncompressed; |
| uint32_t block_length[3] = { 1 << 28, 1 << 28, 1 << 28 }; |
| int block_type[3] = { 0 }; |
| int num_block_types[3] = { 1, 1, 1 }; |
| int block_type_rb[6] = { 0, 1, 0, 1, 0, 1 }; |
| size_t block_type_rb_index[3] = { 0 }; |
| HuffmanTree block_type_trees[3]; |
| HuffmanTree block_len_trees[3]; |
| int distance_postfix_bits; |
| int num_direct_distance_codes; |
| uint32_t distance_postfix_mask; |
| int num_distance_codes; |
| uint8_t* context_map = NULL; |
| uint8_t* context_modes = NULL; |
| int num_literal_htrees; |
| uint8_t* dist_context_map = NULL; |
| int num_dist_htrees; |
| int context_offset = 0; |
| uint8_t* context_map_slice = NULL; |
| uint8_t literal_htree_index = 0; |
| int dist_context_offset = 0; |
| uint8_t* dist_context_map_slice = NULL; |
| uint8_t dist_htree_index = 0; |
| int context_lookup_offset1 = 0; |
| int context_lookup_offset2 = 0; |
| uint8_t context_mode; |
| |
| for (i = 0; i < 3; ++i) { |
| hgroup[i].num_htrees = 0; |
| hgroup[i].htrees = NULL; |
| block_type_trees[i].root_ = NULL; |
| block_len_trees[i].root_ = NULL; |
| } |
| |
| if (!BrotliReadMoreInput(&br)) { |
| printf("[BrotliDecompress] Unexpected end of input.\n"); |
| ok = 0; |
| goto End; |
| } |
| BROTLI_LOG_UINT(pos); |
| DecodeMetaBlockLength(&br, &meta_block_len, &input_end, &is_uncompressed); |
| BROTLI_LOG_UINT(meta_block_len); |
| if (meta_block_len == 0) { |
| goto End; |
| } |
| meta_block_end_pos = pos + meta_block_len; |
| if (is_uncompressed) { |
| BrotliSetBitPos(&br, (br.bit_pos_ + 7) & ~7); |
| for (; pos < meta_block_end_pos; ++pos) { |
| ringbuffer[pos & ringbuffer_mask] = BrotliReadBits(&br, 8); |
| if ((pos & ringbuffer_mask) == ringbuffer_mask) { |
| if (BrotliWrite(output, ringbuffer, ringbuffer_size) < 0) { |
| ok = 0; |
| goto End; |
| } |
| } |
| } |
| goto End; |
| } |
| for (i = 0; i < 3; ++i) { |
| block_type_trees[i].root_ = NULL; |
| block_len_trees[i].root_ = NULL; |
| num_block_types[i] = DecodeVarLenUint8(&br) + 1; |
| if (num_block_types[i] >= 2) { |
| if (!ReadHuffmanCode( |
| num_block_types[i] + 2, &block_type_trees[i], &br) || |
| !ReadHuffmanCode(kNumBlockLengthCodes, &block_len_trees[i], &br)) { |
| ok = 0; |
| goto End; |
| } |
| block_length[i] = ReadBlockLength(&block_len_trees[i], &br); |
| block_type_rb_index[i] = 1; |
| } |
| } |
| |
| BROTLI_LOG_UINT(num_block_types[0]); |
| BROTLI_LOG_UINT(num_block_types[1]); |
| BROTLI_LOG_UINT(num_block_types[2]); |
| BROTLI_LOG_UINT(block_length[0]); |
| BROTLI_LOG_UINT(block_length[1]); |
| BROTLI_LOG_UINT(block_length[2]); |
| |
| if (!BrotliReadMoreInput(&br)) { |
| printf("[BrotliDecompress] Unexpected end of input.\n"); |
| ok = 0; |
| goto End; |
| } |
| distance_postfix_bits = BrotliReadBits(&br, 2); |
| num_direct_distance_codes = NUM_DISTANCE_SHORT_CODES + |
| (BrotliReadBits(&br, 4) << distance_postfix_bits); |
| distance_postfix_mask = (1 << distance_postfix_bits) - 1; |
| num_distance_codes = (num_direct_distance_codes + |
| (48 << distance_postfix_bits)); |
| context_modes = (uint8_t*)malloc(num_block_types[0]); |
| for (i = 0; i < num_block_types[0]; ++i) { |
| context_modes[i] = BrotliReadBits(&br, 2) << 1; |
| BROTLI_LOG_ARRAY_INDEX(context_modes, i); |
| } |
| BROTLI_LOG_UINT(num_direct_distance_codes); |
| BROTLI_LOG_UINT(distance_postfix_bits); |
| |
| if (!DecodeContextMap(num_block_types[0] << kLiteralContextBits, |
| &num_literal_htrees, &context_map, &br) || |
| !DecodeContextMap(num_block_types[2] << kDistanceContextBits, |
| &num_dist_htrees, &dist_context_map, &br)) { |
| ok = 0; |
| goto End; |
| } |
| |
| HuffmanTreeGroupInit(&hgroup[0], kNumLiteralCodes, num_literal_htrees); |
| HuffmanTreeGroupInit(&hgroup[1], kNumInsertAndCopyCodes, |
| num_block_types[1]); |
| HuffmanTreeGroupInit(&hgroup[2], num_distance_codes, num_dist_htrees); |
| |
| for (i = 0; i < 3; ++i) { |
| if (!HuffmanTreeGroupDecode(&hgroup[i], &br)) { |
| ok = 0; |
| goto End; |
| } |
| } |
| |
| context_map_slice = context_map; |
| dist_context_map_slice = dist_context_map; |
| context_mode = context_modes[block_type[0]]; |
| context_lookup_offset1 = kContextLookupOffsets[context_mode]; |
| context_lookup_offset2 = kContextLookupOffsets[context_mode + 1]; |
| |
| while (pos < meta_block_end_pos) { |
| int insert_length; |
| int copy_length; |
| int distance_code; |
| int distance; |
| size_t max_distance; |
| uint8_t context; |
| int j; |
| const uint8_t* copy_src; |
| uint8_t* copy_dst; |
| if (!BrotliReadMoreInput(&br)) { |
| printf("[BrotliDecompress] Unexpected end of input.\n"); |
| ok = 0; |
| goto End; |
| } |
| if (block_length[1] == 0) { |
| DecodeBlockType(block_type_trees, 1, block_type, block_type_rb, |
| block_type_rb_index, &br); |
| block_length[1] = ReadBlockLength(&block_len_trees[1], &br); |
| } |
| --block_length[1]; |
| ReadInsertAndCopy(&hgroup[1].htrees[block_type[1]], |
| &insert_length, ©_length, &distance_code, &br); |
| BROTLI_LOG_UINT(insert_length); |
| BROTLI_LOG_UINT(copy_length); |
| BROTLI_LOG_UINT(distance_code); |
| for (j = 0; j < insert_length; ++j) { |
| if (!BrotliReadMoreInput(&br)) { |
| printf("[BrotliDecompress] Unexpected end of input.\n"); |
| ok = 0; |
| goto End; |
| } |
| if (block_length[0] == 0) { |
| DecodeBlockType(block_type_trees, 0, block_type, block_type_rb, |
| block_type_rb_index, &br); |
| block_length[0] = ReadBlockLength(&block_len_trees[0], &br); |
| context_offset = block_type[0] << kLiteralContextBits; |
| context_map_slice = context_map + context_offset; |
| context_mode = context_modes[block_type[0]]; |
| context_lookup_offset1 = kContextLookupOffsets[context_mode]; |
| context_lookup_offset2 = kContextLookupOffsets[context_mode + 1]; |
| } |
| context = (kContextLookup[context_lookup_offset1 + prev_byte1] | |
| kContextLookup[context_lookup_offset2 + prev_byte2]); |
| BROTLI_LOG_UINT(context); |
| literal_htree_index = context_map_slice[context]; |
| --block_length[0]; |
| prev_byte2 = prev_byte1; |
| prev_byte1 = ReadSymbol(&hgroup[0].htrees[literal_htree_index], &br); |
| ringbuffer[pos & ringbuffer_mask] = prev_byte1; |
| BROTLI_LOG_UINT(literal_htree_index); |
| BROTLI_LOG_ARRAY_INDEX(ringbuffer, pos & ringbuffer_mask); |
| if ((pos & ringbuffer_mask) == ringbuffer_mask) { |
| if (BrotliWrite(output, ringbuffer, ringbuffer_size) < 0) { |
| ok = 0; |
| goto End; |
| } |
| } |
| ++pos; |
| } |
| if (pos == meta_block_end_pos) break; |
| |
| if (distance_code < 0) { |
| uint8_t context; |
| if (!BrotliReadMoreInput(&br)) { |
| printf("[BrotliDecompress] Unexpected end of input.\n"); |
| ok = 0; |
| goto End; |
| } |
| if (block_length[2] == 0) { |
| DecodeBlockType(block_type_trees, 2, block_type, block_type_rb, |
| block_type_rb_index, &br); |
| block_length[2] = ReadBlockLength(&block_len_trees[2], &br); |
| dist_htree_index = block_type[2]; |
| dist_context_offset = block_type[2] << kDistanceContextBits; |
| dist_context_map_slice = dist_context_map + dist_context_offset; |
| } |
| --block_length[2]; |
| context = copy_length > 4 ? 3 : copy_length - 2; |
| dist_htree_index = dist_context_map_slice[context]; |
| distance_code = ReadCopyDistance(&hgroup[2].htrees[dist_htree_index], |
| num_direct_distance_codes, |
| distance_postfix_bits, |
| distance_postfix_mask, |
| &br); |
| } |
| |
| // Convert the distance code to the actual distance by possibly looking |
| // up past distnaces from the ringbuffer. |
| distance = TranslateShortCodes(distance_code, dist_rb, dist_rb_idx); |
| if (distance_code > 0) { |
| dist_rb[dist_rb_idx & 3] = distance; |
| ++dist_rb_idx; |
| } |
| BROTLI_LOG_UINT(distance); |
| |
| max_distance = max_backward_distance; |
| if (pos < max_distance) { |
| max_distance = pos; |
| } |
| |
| copy_dst = &ringbuffer[pos & ringbuffer_mask]; |
| |
| if ((size_t)distance > max_distance) { |
| printf("Invalid backward reference. pos: %lu distance: %d " |
| "len: %d end: %lu\n", (unsigned long)pos, distance, copy_length, |
| (unsigned long)meta_block_end_pos); |
| ok = 0; |
| goto End; |
| } else { |
| if (pos + copy_length > meta_block_end_pos) { |
| printf("Invalid backward reference. pos: %lu distance: %d " |
| "len: %d end: %lu\n", (unsigned long)pos, distance, |
| copy_length, (unsigned long)meta_block_end_pos); |
| ok = 0; |
| goto End; |
| } |
| |
| copy_src = &ringbuffer[(pos - distance) & ringbuffer_mask]; |
| |
| #if (defined(__x86_64__) || defined(_M_X64)) |
| if (copy_src + copy_length <= ringbuffer_end && |
| copy_dst + copy_length < ringbuffer_end) { |
| if (copy_length <= 16 && distance >= 8) { |
| UNALIGNED_COPY64(copy_dst, copy_src); |
| UNALIGNED_COPY64(copy_dst + 8, copy_src + 8); |
| } else { |
| IncrementalCopyFastPath(copy_dst, copy_src, copy_length); |
| } |
| pos += copy_length; |
| copy_length = 0; |
| } |
| #endif |
| |
| for (j = 0; j < copy_length; ++j) { |
| ringbuffer[pos & ringbuffer_mask] = |
| ringbuffer[(pos - distance) & ringbuffer_mask]; |
| if ((pos & ringbuffer_mask) == ringbuffer_mask) { |
| if (BrotliWrite(output, ringbuffer, ringbuffer_size) < 0) { |
| ok = 0; |
| goto End; |
| } |
| } |
| ++pos; |
| } |
| } |
| |
| // When we get here, we must have inserted at least one literal and made |
| // a copy of at least length two, therefore accessing the last 2 bytes is |
| // valid. |
| prev_byte1 = ringbuffer[(pos - 1) & ringbuffer_mask]; |
| prev_byte2 = ringbuffer[(pos - 2) & ringbuffer_mask]; |
| } |
| End: |
| free(context_modes); |
| free(context_map); |
| free(dist_context_map); |
| for (i = 0; i < 3; ++i) { |
| HuffmanTreeGroupRelease(&hgroup[i]); |
| BrotliHuffmanTreeRelease(&block_type_trees[i]); |
| BrotliHuffmanTreeRelease(&block_len_trees[i]); |
| } |
| } |
| |
| if (BrotliWrite(output, ringbuffer, pos & ringbuffer_mask) < 0) { |
| ok = 0; |
| } |
| free(ringbuffer); |
| return ok; |
| } |
| |
| #if defined(__cplusplus) || defined(c_plusplus) |
| } // extern "C" |
| #endif |
