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Updates to Brotli compression format, decoder and encoder

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This commit contains a batch of changes that were made to the Brotli
compression algorithm in the last month. Most important changes:

   * Fixes to the spec.
   * Change of code length code order.
   * Use a 2-level Huffman lookup table in the decoder.
   * Faster uncompressed meta-block decoding.
   * Optimized encoding of the Huffman code.
   * Detection of UTF-8 input encoding.
   * UTF-8 based literal cost modeling for improved
     backward reference selection.
This commit is contained in:
Zoltan Szabadka
2014-02-14 15:04:23 +01:00
parent dfc5a9f215
commit cbd5cb55f4
16 changed files with 912 additions and 635 deletions
Download Patch File Download Diff File Expand all files Collapse all files
brotli/dec/decode.c
+291 -247
View File
@@ -46,9 +46,14 @@ static const int kNumBlockLengthCodes = 26;
static const int kLiteralContextBits = 6;
static const int kDistanceContextBits = 2;
#define HUFFMAN_TABLE_BITS 8
#define HUFFMAN_TABLE_MASK 0xff
/* This is a rough estimate, not an exact bound. */
#define HUFFMAN_MAX_TABLE_SIZE 2048
#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,
1, 2, 3, 4, 0, 5, 17, 6, 16, 7, 8, 9, 10, 11, 12, 13, 14, 15,
};
#define NUM_DISTANCE_SHORT_CODES 16
@@ -104,36 +109,19 @@ static void DecodeMetaBlockLength(BrotliBitReader* br,
}
/* Decodes the next Huffman code from bit-stream. */
static BROTLI_INLINE int ReadSymbol(const HuffmanTree* tree,
static BROTLI_INLINE int ReadSymbol(const HuffmanCode* table,
BrotliBitReader* br) {
uint32_t bits;
uint32_t bitpos;
int lut_ix;
uint8_t lut_bits;
const HuffmanTreeNode* node = tree->root_;
int nbits;
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];
table += (int)(br->val_ >> br->bit_pos_) & HUFFMAN_TABLE_MASK;
nbits = table->bits - HUFFMAN_TABLE_BITS;
if (nbits > 0) {
br->bit_pos_ += HUFFMAN_TABLE_BITS;
table += table->value;
table += (int)(br->val_ >> br->bit_pos_) & ((1 << nbits) - 1);
}
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_;
br->bit_pos_ += table->bits;
return table->value;
}
static void PrintUcharVector(const uint8_t* v, int len) {
@@ -145,47 +133,34 @@ 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 symbol = 0;
uint8_t prev_code_len = kDefaultCodeLength;
int repeat = 0;
uint8_t repeat_length = 0;
uint8_t repeat_code_len = 0;
int space = 32768;
HuffmanTree tree;
HuffmanCode table[32];
if (!BrotliHuffmanTreeBuildImplicit(&tree, code_length_code_lengths,
CODE_LENGTH_CODES)) {
if (!BrotliBuildHuffmanTable(table, 5,
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;
}
symbol = 0;
while (symbol + repeat < num_symbols && space > 0) {
while (symbol < num_symbols && space > 0) {
const HuffmanCode* p = table;
uint8_t code_len;
if (!BrotliReadMoreInput(br)) {
printf("[ReadHuffmanCodeLengths] Unexpected end of input.\n");
goto End;
}
code_len = (uint8_t)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;
}
return 0;
}
BrotliFillBitWindow(br);
p += (br->val_ >> br->bit_pos_) & 31;
br->bit_pos_ += p->bits;
code_len = (uint8_t)p->value;
if (code_len < kCodeLengthRepeatCode) {
repeat = 0;
code_lengths[symbol++] = code_len;
if (code_len != 0) {
prev_code_len = code_len;
@@ -193,47 +168,46 @@ static int ReadHuffmanCodeLengths(
}
} else {
const int extra_bits = code_len - 14;
int i = repeat;
int old_repeat;
int repeat_delta;
uint8_t new_len = 0;
if (code_len == kCodeLengthRepeatCode) {
new_len = prev_code_len;
}
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 += (int)BrotliReadBits(br, extra_bits) + 3;
if (repeat + symbol > num_symbols) {
goto End;
repeat_delta = repeat - old_repeat;
if (symbol + repeat_delta > num_symbols) {
return 0;
}
if (code_len == kCodeLengthRepeatCode) {
repeat_length = prev_code_len;
for (; i < repeat; ++i) {
space -= 32768 >> repeat_length;
}
} else {
repeat_length = 0;
memset(&code_lengths[symbol], repeat_code_len, (size_t)repeat_delta);
symbol += repeat_delta;
if (repeat_code_len != 0) {
space -= repeat_delta << (15 - repeat_code_len);
}
}
}
if (space != 0) {
printf("[ReadHuffmanCodeLengths] space = %d\n", space);
goto End;
return 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;
memset(&code_lengths[symbol], 0, (size_t)(num_symbols - symbol));
return 1;
}
static int ReadHuffmanCode(int alphabet_size,
HuffmanTree* tree,
HuffmanCode* table,
BrotliBitReader* br) {
int ok = 1;
int table_size = 0;
int simple_code_or_skip;
uint8_t* code_lengths = NULL;
@@ -290,109 +264,49 @@ static int ReadHuffmanCode(int alphabet_size,
int i;
uint8_t code_length_code_lengths[CODE_LENGTH_CODES] = { 0 };
int space = 32;
for (i = simple_code_or_skip;
i < CODE_LENGTH_CODES && space > 0; ++i) {
int code_len_idx = kCodeLengthCodeOrder[i];
uint8_t v = (uint8_t)BrotliReadBits(br, 2);
if (v == 1) {
v = (uint8_t)BrotliReadBits(br, 1);
if (v == 0) {
v = 2;
} else {
v = (uint8_t)BrotliReadBits(br, 1);
if (v == 0) {
v = 1;
} else {
v = 5;
}
}
} else if (v == 2) {
v = 4;
}
/* Static Huffman code for the code length code lengths */
static const HuffmanCode huff[16] = {
{2, 0}, {2, 4}, {2, 3}, {3, 2}, {2, 0}, {2, 4}, {2, 3}, {4, 1},
{2, 0}, {2, 4}, {2, 3}, {3, 2}, {2, 0}, {2, 4}, {2, 3}, {4, 5},
};
for (i = simple_code_or_skip; i < CODE_LENGTH_CODES && space > 0; ++i) {
const int code_len_idx = kCodeLengthCodeOrder[i];
const HuffmanCode* p = huff;
uint8_t v;
BrotliFillBitWindow(br);
p += (br->val_ >> br->bit_pos_) & 15;
br->bit_pos_ += p->bits;
v = (uint8_t)p->value;
code_length_code_lengths[code_len_idx] = v;
BROTLI_LOG_ARRAY_INDEX(code_length_code_lengths, code_len_idx);
if (v != 0) {
space -= (32 >> v);
}
}
ok = ReadHuffmanCodeLengths(code_length_code_lengths, alphabet_size,
code_lengths, br);
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: ");
table_size = BrotliBuildHuffmanTable(table, HUFFMAN_TABLE_BITS,
code_lengths, alphabet_size);
if (table_size == 0) {
printf("[ReadHuffmanCode] BuildHuffmanTable failed: ");
PrintUcharVector(code_lengths, alphabet_size);
}
}
free(code_lengths);
return ok;
return table_size;
}
static int ReadCopyDistance(const HuffmanTree* tree,
int num_direct_codes,
int postfix_bits,
int postfix_mask,
BrotliBitReader* br) {
static BROTLI_INLINE int ReadBlockLength(const HuffmanCode* table,
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 + (int)BrotliReadBits(br, nbits)) << postfix_bits) +
postfix);
}
static int ReadBlockLength(const HuffmanTree* tree, BrotliBitReader* br) {
int code;
int nbits;
code = ReadSymbol(tree, br);
code = ReadSymbol(table, br);
nbits = kBlockLengthPrefixCode[code].nbits;
return kBlockLengthPrefixCode[code].offset + (int)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 += (int)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 += (int)BrotliReadBits(br, copy_extra_bits);
}
}
static int TranslateShortCodes(int code, int* ringbuffer, int index) {
int val;
if (code < NUM_DISTANCE_SHORT_CODES) {
@@ -429,24 +343,22 @@ static void InverseMoveToFrontTransform(uint8_t* v, int v_len) {
typedef struct {
int alphabet_size;
int num_htrees;
HuffmanTree* htrees;
HuffmanCode* codes;
HuffmanCode** htrees;
} HuffmanTreeGroup;
static void HuffmanTreeGroupInit(HuffmanTreeGroup* group, int alphabet_size,
int ntrees) {
int i;
group->alphabet_size = alphabet_size;
group->num_htrees = ntrees;
group->htrees = (HuffmanTree*)malloc(sizeof(HuffmanTree) * (size_t)ntrees);
for (i = 0; i < ntrees; ++i) {
group->htrees[i].root_ = NULL;
}
group->codes = (HuffmanCode*)malloc(
sizeof(HuffmanCode) * (size_t)(ntrees * HUFFMAN_MAX_TABLE_SIZE));
group->htrees = (HuffmanCode**)malloc(sizeof(HuffmanCode*) * (size_t)ntrees);
}
static void HuffmanTreeGroupRelease(HuffmanTreeGroup* group) {
int i;
for (i = 0; i < group->num_htrees; ++i) {
BrotliHuffmanTreeRelease(&group->htrees[i]);
if (group->codes) {
free(group->codes);
}
if (group->htrees) {
free(group->htrees);
@@ -456,8 +368,13 @@ static void HuffmanTreeGroupRelease(HuffmanTreeGroup* group) {
static int HuffmanTreeGroupDecode(HuffmanTreeGroup* group,
BrotliBitReader* br) {
int i;
int table_size;
HuffmanCode* next = group->codes;
for (i = 0; i < group->num_htrees; ++i) {
if (!ReadHuffmanCode(group->alphabet_size, &group->htrees[i], br)) {
group->htrees[i] = next;
table_size = ReadHuffmanCode(group->alphabet_size, next, br);
next += table_size;
if (table_size == 0) {
return 0;
}
}
@@ -469,6 +386,10 @@ static int DecodeContextMap(int context_map_size,
uint8_t** context_map,
BrotliBitReader* br) {
int ok = 1;
int use_rle_for_zeros;
int max_run_length_prefix = 0;
HuffmanCode* table;
int i;
if (!BrotliReadMoreInput(br)) {
printf("[DecodeContextMap] Unexpected end of input.\n");
return 0;
@@ -487,55 +408,54 @@ static int DecodeContextMap(int context_map_size,
return 1;
}
{
HuffmanTree tree_index_htree;
int use_rle_for_zeros = (int)BrotliReadBits(br, 1);
int max_run_length_prefix = 0;
int i;
if (use_rle_for_zeros) {
max_run_length_prefix = (int)BrotliReadBits(br, 4) + 1;
use_rle_for_zeros = (int)BrotliReadBits(br, 1);
if (use_rle_for_zeros) {
max_run_length_prefix = (int)BrotliReadBits(br, 4) + 1;
}
table = (HuffmanCode*)malloc(HUFFMAN_MAX_TABLE_SIZE * sizeof(*table));
if (table == NULL) {
return 0;
}
if (!ReadHuffmanCode(*num_htrees + max_run_length_prefix, table, br)) {
ok = 0;
goto End;
}
for (i = 0; i < context_map_size;) {
int code;
if (!BrotliReadMoreInput(br)) {
printf("[DecodeContextMap] Unexpected end of input.\n");
ok = 0;
goto End;
}
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) {
code = ReadSymbol(table, br);
if (code == 0) {
(*context_map)[i] = 0;
++i;
} else if (code <= max_run_length_prefix) {
int reps = 1 + (1 << code) + (int)BrotliReadBits(br, code);
while (--reps) {
if (i >= context_map_size) {
ok = 0;
goto End;
}
(*context_map)[i] = 0;
++i;
} else if (code <= max_run_length_prefix) {
int reps = 1 + (1 << code) + (int)BrotliReadBits(br, code);
while (--reps) {
if (i >= context_map_size) {
ok = 0;
goto End;
}
(*context_map)[i] = 0;
++i;
}
} else {
(*context_map)[i] = (uint8_t)(code - max_run_length_prefix);
++i;
}
} else {
(*context_map)[i] = (uint8_t)(code - max_run_length_prefix);
++i;
}
End:
BrotliHuffmanTreeRelease(&tree_index_htree);
}
if (BrotliReadBits(br, 1)) {
InverseMoveToFrontTransform(*context_map, context_map_size);
}
End:
free(table);
return ok;
}
static BROTLI_INLINE void DecodeBlockType(const int max_block_type,
const HuffmanTree* trees,
const HuffmanCode* trees,
int tree_type,
int* block_types,
int* ringbuffers,
@@ -543,7 +463,7 @@ static BROTLI_INLINE void DecodeBlockType(const int max_block_type,
BrotliBitReader* br) {
int* ringbuffer = ringbuffers + tree_type * 2;
int* index = indexes + tree_type;
int type_code = ReadSymbol(trees + tree_type, br);
int type_code = ReadSymbol(&trees[tree_type * HUFFMAN_MAX_TABLE_SIZE], br);
int block_type;
if (type_code == 0) {
block_type = ringbuffer[*index & 1];
@@ -608,6 +528,92 @@ static BROTLI_INLINE void IncrementalCopyFastPath(
}
}
int CopyUncompressedBlockToOutput(BrotliOutput output, int len, int pos,
uint8_t* ringbuffer, int ringbuffer_mask,
BrotliBitReader* br) {
const int rb_size = ringbuffer_mask + 1;
uint8_t* ringbuffer_end = ringbuffer + rb_size;
int rb_pos = pos & ringbuffer_mask;
int br_pos = br->pos_ & BROTLI_IBUF_MASK;
int nbytes;
/* For short lengths copy byte-by-byte */
if (len < 8 || br->bit_pos_ + (uint32_t)(len << 3) < br->bit_end_pos_) {
while (len-- > 0) {
if (!BrotliReadMoreInput(br)) {
return 0;
}
ringbuffer[rb_pos++]= (uint8_t)BrotliReadBits(br, 8);
if (rb_pos == rb_size) {
if (BrotliWrite(output, ringbuffer, (size_t)rb_size) < rb_size) {
return 0;
}
rb_pos = 0;
}
}
return 1;
}
if (br->bit_end_pos_ < 64) {
return 0;
}
/* Copy remaining 0-8 bytes from br->val_ to ringbuffer. */
while (br->bit_pos_ < 64) {
ringbuffer[rb_pos] = (uint8_t)(br->val_ >> br->bit_pos_);
br->bit_pos_ += 8;
++rb_pos;
--len;
}
/* Copy remaining bytes from br->buf_ to ringbuffer. */
nbytes = (int)(br->bit_end_pos_ - br->bit_pos_) >> 3;
if (br_pos + nbytes > BROTLI_IBUF_MASK) {
int tail = BROTLI_IBUF_MASK + 1 - br_pos;
memcpy(&ringbuffer[rb_pos], &br->buf_[br_pos], (size_t)tail);
nbytes -= tail;
rb_pos += tail;
len -= tail;
br_pos = 0;
}
memcpy(&ringbuffer[rb_pos], &br->buf_[br_pos], (size_t)nbytes);
rb_pos += nbytes;
len -= nbytes;
/* If we wrote past the logical end of the ringbuffer, copy the tail of the
ringbuffer to its beginning and flush the ringbuffer to the output. */
if (rb_pos >= rb_size) {
if (BrotliWrite(output, ringbuffer, (size_t)rb_size) < rb_size) {
return 0;
}
rb_pos -= rb_size;
memcpy(ringbuffer, ringbuffer_end, (size_t)rb_pos);
}
/* If we have more to copy than the remaining size of the ringbuffer, then we
first fill the ringbuffer from the input and then flush the ringbuffer to
the output */
while (rb_pos + len >= rb_size) {
nbytes = rb_size - rb_pos;
if (BrotliRead(br->input_, &ringbuffer[rb_pos], (size_t)nbytes) < nbytes ||
BrotliWrite(output, ringbuffer, (size_t)rb_size) < nbytes) {
return 0;
}
len -= nbytes;
rb_pos = 0;
}
/* Copy straight from the input onto the ringbuffer. The ringbuffer will be
flushed to the output at a later time. */
if (BrotliRead(br->input_, &ringbuffer[rb_pos], (size_t)len) < len) {
return 0;
}
/* Restore the state of the bit reader. */
BrotliInitBitReader(br, br->input_);
return 1;
}
int BrotliDecompressedSize(size_t encoded_size,
const uint8_t* encoded_buffer,
size_t* decoded_size) {
@@ -662,11 +668,15 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
uint8_t prev_byte1 = 0;
uint8_t prev_byte2 = 0;
HuffmanTreeGroup hgroup[3];
HuffmanCode* block_type_trees = NULL;
HuffmanCode* block_len_trees = NULL;
BrotliBitReader br;
/* 16 bytes would be enough, but we add some more slack for transforms */
/* to work at the end of the ringbuffer. */
static const int kRingBufferWriteAheadSlack = 128;
/* We need the slack region for the following reasons:
- always doing two 8-byte copies for fast backward copying
- transforms
- flushing the input ringbuffer when decoding uncompressed blocks */
static const int kRingBufferWriteAheadSlack = 128 + BROTLI_READ_SIZE;
static const int kMaxDictionaryWordLength = 0;
@@ -688,6 +698,16 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
}
ringbuffer_end = ringbuffer + ringbuffer_size;
if (ok) {
block_type_trees = (HuffmanCode*)malloc(
3 * HUFFMAN_MAX_TABLE_SIZE * sizeof(HuffmanCode));
block_len_trees = (HuffmanCode*)malloc(
3 * HUFFMAN_MAX_TABLE_SIZE * sizeof(HuffmanCode));
if (block_type_trees == NULL || block_len_trees == NULL) {
ok = 0;
}
}
while (!input_end && ok) {
int meta_block_remaining_len = 0;
int is_uncompressed;
@@ -696,8 +716,6 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
int num_block_types[3] = { 1, 1, 1 };
int block_type_rb[6] = { 0, 1, 0, 1, 0, 1 };
int 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;
int distance_postfix_mask;
@@ -716,12 +734,11 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
int context_lookup_offset1 = 0;
int context_lookup_offset2 = 0;
uint8_t context_mode;
HuffmanCode* htree_command;
for (i = 0; i < 3; ++i) {
hgroup[i].num_htrees = 0;
hgroup[i].codes = NULL;
hgroup[i].htrees = NULL;
block_type_trees[i].root_ = NULL;
block_len_trees[i].root_ = NULL;
}
if (!BrotliReadMoreInput(&br)) {
@@ -738,31 +755,25 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
}
if (is_uncompressed) {
BrotliSetBitPos(&br, (br.bit_pos_ + 7) & (uint32_t)(~7UL));
while (meta_block_remaining_len) {
ringbuffer[pos & ringbuffer_mask] = (uint8_t)BrotliReadBits(&br, 8);
if ((pos & ringbuffer_mask) == ringbuffer_mask) {
if (BrotliWrite(output, ringbuffer, (size_t)ringbuffer_size) < 0) {
ok = 0;
goto End;
}
}
++pos;
--meta_block_remaining_len;
}
ok = CopyUncompressedBlockToOutput(output, meta_block_remaining_len, pos,
ringbuffer, ringbuffer_mask, &br);
pos += meta_block_remaining_len;
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)) {
if (!ReadHuffmanCode(num_block_types[i] + 2,
&block_type_trees[i * HUFFMAN_MAX_TABLE_SIZE],
&br) ||
!ReadHuffmanCode(kNumBlockLengthCodes,
&block_len_trees[i * HUFFMAN_MAX_TABLE_SIZE],
&br)) {
ok = 0;
goto End;
}
block_length[i] = ReadBlockLength(&block_len_trees[i], &br);
block_length[i] = ReadBlockLength(
&block_len_trees[i * HUFFMAN_MAX_TABLE_SIZE], &br);
block_type_rb_index[i] = 1;
}
}
@@ -822,8 +833,13 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
context_mode = context_modes[block_type[0]];
context_lookup_offset1 = kContextLookupOffsets[context_mode];
context_lookup_offset2 = kContextLookupOffsets[context_mode + 1];
htree_command = hgroup[1].htrees[0];
while (meta_block_remaining_len > 0) {
int cmd_code;
int range_idx;
int insert_code;
int copy_code;
int insert_length;
int copy_length;
int distance_code;
@@ -841,11 +857,25 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
DecodeBlockType(num_block_types[1],
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] = ReadBlockLength(
&block_len_trees[HUFFMAN_MAX_TABLE_SIZE], &br);
htree_command = hgroup[1].htrees[block_type[1]];
}
--block_length[1];
ReadInsertAndCopy(&hgroup[1].htrees[block_type[1]],
&insert_length, &copy_length, &distance_code, &br);
cmd_code = ReadSymbol(htree_command, &br);
range_idx = cmd_code >> 6;
if (range_idx >= 2) {
range_idx -= 2;
distance_code = -1;
} else {
distance_code = 0;
}
insert_code = kInsertRangeLut[range_idx] + ((cmd_code >> 3) & 7);
copy_code = kCopyRangeLut[range_idx] + (cmd_code & 7);
insert_length = kInsertLengthPrefixCode[insert_code].offset +
(int)BrotliReadBits(&br, kInsertLengthPrefixCode[insert_code].nbits);
copy_length = kCopyLengthPrefixCode[copy_code].offset +
(int)BrotliReadBits(&br, kCopyLengthPrefixCode[copy_code].nbits);
BROTLI_LOG_UINT(insert_length);
BROTLI_LOG_UINT(copy_length);
BROTLI_LOG_UINT(distance_code);
@@ -859,7 +889,7 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
DecodeBlockType(num_block_types[0],
block_type_trees, 0, block_type, block_type_rb,
block_type_rb_index, &br);
block_length[0] = ReadBlockLength(&block_len_trees[0], &br);
block_length[0] = ReadBlockLength(block_len_trees, &br);
context_offset = block_type[0] << kLiteralContextBits;
context_map_slice = context_map + context_offset;
context_mode = context_modes[block_type[0]];
@@ -872,7 +902,7 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
literal_htree_index = context_map_slice[context];
--block_length[0];
prev_byte2 = prev_byte1;
prev_byte1 = (uint8_t)ReadSymbol(&hgroup[0].htrees[literal_htree_index],
prev_byte1 = (uint8_t)ReadSymbol(hgroup[0].htrees[literal_htree_index],
&br);
ringbuffer[pos & ringbuffer_mask] = prev_byte1;
BROTLI_LOG_UINT(literal_htree_index);
@@ -899,7 +929,8 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
DecodeBlockType(num_block_types[2],
block_type_trees, 2, block_type, block_type_rb,
block_type_rb_index, &br);
block_length[2] = ReadBlockLength(&block_len_trees[2], &br);
block_length[2] = ReadBlockLength(
&block_len_trees[2 * HUFFMAN_MAX_TABLE_SIZE], &br);
dist_htree_index = (uint8_t)block_type[2];
dist_context_offset = block_type[2] << kDistanceContextBits;
dist_context_map_slice = dist_context_map + dist_context_offset;
@@ -907,11 +938,20 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
--block_length[2];
context = (uint8_t)(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);
distance_code = ReadSymbol(hgroup[2].htrees[dist_htree_index], &br);
if (distance_code >= num_direct_distance_codes) {
int nbits;
int postfix;
int offset;
distance_code -= num_direct_distance_codes;
postfix = distance_code & distance_postfix_mask;
distance_code >>= distance_postfix_bits;
nbits = (distance_code >> 1) + 1;
offset = ((2 + (distance_code & 1)) << nbits) - 4;
distance_code = num_direct_distance_codes +
((offset + (int)BrotliReadBits(&br, nbits)) <<
distance_postfix_bits) + postfix;
}
}
/* Convert the distance code to the actual distance by possibly looking */
@@ -1004,8 +1044,6 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
}
for (i = 0; i < 3; ++i) {
HuffmanTreeGroupRelease(&hgroup[i]);
BrotliHuffmanTreeRelease(&block_type_trees[i]);
BrotliHuffmanTreeRelease(&block_len_trees[i]);
}
}
@@ -1015,6 +1053,12 @@ int BrotliDecompress(BrotliInput input, BrotliOutput output) {
}
free(ringbuffer);
}
if (block_type_trees != 0) {
free(block_type_trees);
}
if (block_len_trees != 0) {
free(block_len_trees);
}
return ok;
}