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f46606843f
libwebp/4619a48fc-1.0.0.patch
Tomas Popela f46606843f Added fix for CVE-2023-4863 
Resolves: RHEL-3855
2023-09-15 14:07:40 +02:00

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diff -up libwebp-1.0.0/src/dec/vp8l_dec.c.old libwebp-1.0.0/src/dec/vp8l_dec.c
--- libwebp-1.0.0/src/dec/vp8l_dec.c.old 2023-09-15 11:07:05.229790896 +0200
+++ libwebp-1.0.0/src/dec/vp8l_dec.c 2023-09-15 10:54:47.046025885 +0200
@@ -253,11 +253,11 @@ static int ReadHuffmanCodeLengths(
int symbol;
int max_symbol;
int prev_code_len = DEFAULT_CODE_LENGTH;
- HuffmanCode table[1 << LENGTHS_TABLE_BITS];
+ HuffmanTables tables;
- if (!VP8LBuildHuffmanTable(table, LENGTHS_TABLE_BITS,
- code_length_code_lengths,
- NUM_CODE_LENGTH_CODES)) {
+ if (!VP8LHuffmanTablesAllocate(1 << LENGTHS_TABLE_BITS, &tables) ||
+ !VP8LBuildHuffmanTable(&tables, LENGTHS_TABLE_BITS,
+ code_length_code_lengths, NUM_CODE_LENGTH_CODES)) {
goto End;
}
@@ -277,7 +277,7 @@ static int ReadHuffmanCodeLengths(
int code_len;
if (max_symbol-- == 0) break;
VP8LFillBitWindow(br);
- p = &table[VP8LPrefetchBits(br) & LENGTHS_TABLE_MASK];
+ p = &tables.curr_segment->start[VP8LPrefetchBits(br) & LENGTHS_TABLE_MASK];
VP8LSetBitPos(br, br->bit_pos_ + p->bits);
code_len = p->value;
if (code_len < kCodeLengthLiterals) {
@@ -300,6 +300,7 @@ static int ReadHuffmanCodeLengths(
ok = 1;
End:
+ VP8LHuffmanTablesDeallocate(&tables);
if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
return ok;
}
@@ -307,7 +308,8 @@ static int ReadHuffmanCodeLengths(
// 'code_lengths' is pre-allocated temporary buffer, used for creating Huffman
// tree.
static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
- int* const code_lengths, HuffmanCode* const table) {
+ int* const code_lengths,
+ HuffmanTables* const table) {
int ok = 0;
int size = 0;
VP8LBitReader* const br = &dec->br_;
@@ -362,12 +364,7 @@ static int ReadHuffmanCodes(VP8LDecoder*
VP8LMetadata* const hdr = &dec->hdr_;
uint32_t* huffman_image = NULL;
HTreeGroup* htree_groups = NULL;
- // When reading htrees, some might be unused, as the format allows it.
- // We will still read them but put them in this htree_group_bogus.
- HTreeGroup htree_group_bogus;
- HuffmanCode* huffman_tables = NULL;
- HuffmanCode* huffman_tables_bogus = NULL;
- HuffmanCode* next = NULL;
+ HuffmanTables* huffman_tables = &hdr->huffman_tables_;
int num_htree_groups = 1;
int num_htree_groups_max = 1;
int max_alphabet_size = 0;
@@ -376,6 +373,10 @@ static int ReadHuffmanCodes(VP8LDecoder*
int* mapping = NULL;
int ok = 0;
+ // Check the table has been 0 initialized (through InitMetadata).
+ assert(huffman_tables->root.start == NULL);
+ assert(huffman_tables->curr_segment == NULL);
+
if (allow_recursion && VP8LReadBits(br, 1)) {
// use meta Huffman codes.
const int huffman_precision = VP8LReadBits(br, 3) + 2;
@@ -418,12 +419,6 @@ static int ReadHuffmanCodes(VP8LDecoder*
if (*mapped_group == -1) *mapped_group = num_htree_groups++;
huffman_image[i] = *mapped_group;
}
- huffman_tables_bogus = (HuffmanCode*)WebPSafeMalloc(
- table_size, sizeof(*huffman_tables_bogus));
- if (huffman_tables_bogus == NULL) {
- dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
- goto Error;
- }
} else {
num_htree_groups = num_htree_groups_max;
}
@@ -444,72 +439,80 @@ static int ReadHuffmanCodes(VP8LDecoder*
code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
sizeof(*code_lengths));
- huffman_tables = (HuffmanCode*)WebPSafeMalloc(num_htree_groups * table_size,
- sizeof(*huffman_tables));
htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
- if (htree_groups == NULL || code_lengths == NULL || huffman_tables == NULL) {
+ if (htree_groups == NULL || code_lengths == NULL ||
+ !VP8LHuffmanTablesAllocate(num_htree_groups * table_size,
+ huffman_tables)) {
dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
goto Error;
}
- next = huffman_tables;
for (i = 0; i < num_htree_groups_max; ++i) {
- // If the index "i" is unused in the Huffman image, read the coefficients
- // but store them to a bogus htree_group.
- const int is_bogus = (mapping != NULL && mapping[i] == -1);
- HTreeGroup* const htree_group =
- is_bogus ? &htree_group_bogus :
- &htree_groups[(mapping == NULL) ? i : mapping[i]];
- HuffmanCode** const htrees = htree_group->htrees;
- HuffmanCode* huffman_tables_i = is_bogus ? huffman_tables_bogus : next;
- int size;
- int total_size = 0;
- int is_trivial_literal = 1;
- int max_bits = 0;
- for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
- int alphabet_size = kAlphabetSize[j];
- htrees[j] = huffman_tables_i;
- if (j == 0 && color_cache_bits > 0) {
- alphabet_size += 1 << color_cache_bits;
- }
- size =
- ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_tables_i);
- if (size == 0) {
- goto Error;
- }
- if (is_trivial_literal && kLiteralMap[j] == 1) {
- is_trivial_literal = (huffman_tables_i->bits == 0);
+ // If the index "i" is unused in the Huffman image, just make sure the
+ // coefficients are valid but do not store them.
+ if (mapping != NULL && mapping[i] == -1) {
+ for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
+ int alphabet_size = kAlphabetSize[j];
+ if (j == 0 && color_cache_bits > 0) {
+ alphabet_size += (1 << color_cache_bits);
+ }
+ // Passing in NULL so that nothing gets filled.
+ if (!ReadHuffmanCode(alphabet_size, dec, code_lengths, NULL)) {
+ goto Error;
+ }
}
- total_size += huffman_tables_i->bits;
- huffman_tables_i += size;
- if (j <= ALPHA) {
- int local_max_bits = code_lengths[0];
- int k;
- for (k = 1; k < alphabet_size; ++k) {
- if (code_lengths[k] > local_max_bits) {
- local_max_bits = code_lengths[k];
+ } else {
+ HTreeGroup* const htree_group =
+ &htree_groups[(mapping == NULL) ? i : mapping[i]];
+ HuffmanCode** const htrees = htree_group->htrees;
+ int size;
+ int total_size = 0;
+ int is_trivial_literal = 1;
+ int max_bits = 0;
+ for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
+ int alphabet_size = kAlphabetSize[j];
+ if (j == 0 && color_cache_bits > 0) {
+ alphabet_size += (1 << color_cache_bits);
+ }
+ size =
+ ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_tables);
+ htrees[j] = huffman_tables->curr_segment->curr_table;
+ if (size == 0) {
+ goto Error;
+ }
+ if (is_trivial_literal && kLiteralMap[j] == 1) {
+ is_trivial_literal = (htrees[j]->bits == 0);
+ }
+ total_size += htrees[j]->bits;
+ huffman_tables->curr_segment->curr_table += size;
+ if (j <= ALPHA) {
+ int local_max_bits = code_lengths[0];
+ int k;
+ for (k = 1; k < alphabet_size; ++k) {
+ if (code_lengths[k] > local_max_bits) {
+ local_max_bits = code_lengths[k];
+ }
}
+ max_bits += local_max_bits;
}
- max_bits += local_max_bits;
}
- }
- if (!is_bogus) next = huffman_tables_i;
- htree_group->is_trivial_literal = is_trivial_literal;
- htree_group->is_trivial_code = 0;
- if (is_trivial_literal) {
- const int red = htrees[RED][0].value;
- const int blue = htrees[BLUE][0].value;
- const int alpha = htrees[ALPHA][0].value;
- htree_group->literal_arb = ((uint32_t)alpha << 24) | (red << 16) | blue;
- if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) {
- htree_group->is_trivial_code = 1;
- htree_group->literal_arb |= htrees[GREEN][0].value << 8;
+ htree_group->is_trivial_literal = is_trivial_literal;
+ htree_group->is_trivial_code = 0;
+ if (is_trivial_literal) {
+ const int red = htrees[RED][0].value;
+ const int blue = htrees[BLUE][0].value;
+ const int alpha = htrees[ALPHA][0].value;
+ htree_group->literal_arb = ((uint32_t)alpha << 24) | (red << 16) | blue;
+ if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) {
+ htree_group->is_trivial_code = 1;
+ htree_group->literal_arb |= htrees[GREEN][0].value << 8;
+ }
}
+ htree_group->use_packed_table =
+ !htree_group->is_trivial_code && (max_bits < HUFFMAN_PACKED_BITS);
+ if (htree_group->use_packed_table) BuildPackedTable(htree_group);
}
- htree_group->use_packed_table =
- !htree_group->is_trivial_code && (max_bits < HUFFMAN_PACKED_BITS);
- if (htree_group->use_packed_table) BuildPackedTable(htree_group);
}
ok = 1;
@@ -517,15 +520,13 @@ static int ReadHuffmanCodes(VP8LDecoder*
hdr->huffman_image_ = huffman_image;
hdr->num_htree_groups_ = num_htree_groups;
hdr->htree_groups_ = htree_groups;
- hdr->huffman_tables_ = huffman_tables;
Error:
WebPSafeFree(code_lengths);
- WebPSafeFree(huffman_tables_bogus);
WebPSafeFree(mapping);
if (!ok) {
WebPSafeFree(huffman_image);
- WebPSafeFree(huffman_tables);
+ VP8LHuffmanTablesDeallocate(huffman_tables);
VP8LHtreeGroupsFree(htree_groups);
}
return ok;
@@ -757,11 +758,11 @@ static WEBP_INLINE HTreeGroup* GetHtreeG
typedef void (*ProcessRowsFunc)(VP8LDecoder* const dec, int row);
-static void ApplyInverseTransforms(VP8LDecoder* const dec, int num_rows,
+static void ApplyInverseTransforms(VP8LDecoder* const dec,
+ int start_row, int num_rows,
const uint32_t* const rows) {
int n = dec->next_transform_;
const int cache_pixs = dec->width_ * num_rows;
- const int start_row = dec->last_row_;
const int end_row = start_row + num_rows;
const uint32_t* rows_in = rows;
uint32_t* const rows_out = dec->argb_cache_;
@@ -792,8 +793,7 @@ static void ProcessRows(VP8LDecoder* con
VP8Io* const io = dec->io_;
uint8_t* rows_data = (uint8_t*)dec->argb_cache_;
const int in_stride = io->width * sizeof(uint32_t); // in unit of RGBA
-
- ApplyInverseTransforms(dec, num_rows, rows);
+ ApplyInverseTransforms(dec, dec->last_row_, num_rows, rows);
if (!SetCropWindow(io, dec->last_row_, row, &rows_data, in_stride)) {
// Nothing to output (this time).
} else {
@@ -951,7 +951,6 @@ static WEBP_INLINE void CopyBlock8b(uint
break;
default:
goto Copy;
- break;
}
CopySmallPattern8b(src, dst, length, pattern);
return;
@@ -1196,6 +1195,7 @@ static int DecodeImageData(VP8LDecoder*
VP8LFillBitWindow(br);
dist_code = GetCopyDistance(dist_symbol, br);
dist = PlaneCodeToDistance(width, dist_code);
+
if (VP8LIsEndOfStream(br)) break;
if (src - data < (ptrdiff_t)dist || src_end - src < (ptrdiff_t)length) {
goto Error;
@@ -1357,7 +1357,7 @@ static void ClearMetadata(VP8LMetadata*
assert(hdr != NULL);
WebPSafeFree(hdr->huffman_image_);
- WebPSafeFree(hdr->huffman_tables_);
+ VP8LHuffmanTablesDeallocate(&hdr->huffman_tables_);
VP8LHtreeGroupsFree(hdr->htree_groups_);
VP8LColorCacheClear(&hdr->color_cache_);
VP8LColorCacheClear(&hdr->saved_color_cache_);
@@ -1556,7 +1556,7 @@ static void ExtractAlphaRows(VP8LDecoder
const int cache_pixs = width * num_rows_to_process;
uint8_t* const dst = output + width * cur_row;
const uint32_t* const src = dec->argb_cache_;
- ApplyInverseTransforms(dec, num_rows_to_process, in);
+ ApplyInverseTransforms(dec, cur_row, num_rows_to_process, in);
WebPExtractGreen(src, dst, cache_pixs);
AlphaApplyFilter(alph_dec,
cur_row, cur_row + num_rows_to_process, dst, width);
@@ -1673,7 +1673,7 @@ int VP8LDecodeImage(VP8LDecoder* const d
// Sanity checks.
if (dec == NULL) return 0;
- assert(dec->hdr_.huffman_tables_ != NULL);
+ assert(dec->hdr_.huffman_tables_.root.start != NULL);
assert(dec->hdr_.htree_groups_ != NULL);
assert(dec->hdr_.num_htree_groups_ > 0);
diff -up libwebp-1.0.0/src/dec/vp8li_dec.h.old libwebp-1.0.0/src/dec/vp8li_dec.h
--- libwebp-1.0.0/src/dec/vp8li_dec.h.old 2023-09-15 11:07:13.032063220 +0200
+++ libwebp-1.0.0/src/dec/vp8li_dec.h 2023-09-15 10:54:47.046025885 +0200
@@ -37,7 +37,7 @@ struct VP8LTransform {
int bits_; // subsampling bits defining transform window.
int xsize_; // transform window X index.
int ysize_; // transform window Y index.
- uint32_t *data_; // transform data.
+ uint32_t* data_; // transform data.
};
typedef struct {
@@ -48,23 +48,23 @@ typedef struct {
int huffman_mask_;
int huffman_subsample_bits_;
int huffman_xsize_;
- uint32_t *huffman_image_;
+ uint32_t* huffman_image_;
int num_htree_groups_;
- HTreeGroup *htree_groups_;
- HuffmanCode *huffman_tables_;
+ HTreeGroup* htree_groups_;
+ HuffmanTables huffman_tables_;
} VP8LMetadata;
typedef struct VP8LDecoder VP8LDecoder;
struct VP8LDecoder {
VP8StatusCode status_;
VP8LDecodeState state_;
- VP8Io *io_;
+ VP8Io* io_;
- const WebPDecBuffer *output_; // shortcut to io->opaque->output
+ const WebPDecBuffer* output_; // shortcut to io->opaque->output
- uint32_t *pixels_; // Internal data: either uint8_t* for alpha
+ uint32_t* pixels_; // Internal data: either uint8_t* for alpha
// or uint32_t* for BGRA.
- uint32_t *argb_cache_; // Scratch buffer for temporary BGRA storage.
+ uint32_t* argb_cache_; // Scratch buffer for temporary BGRA storage.
VP8LBitReader br_;
int incremental_; // if true, incremental decoding is expected
@@ -86,8 +86,8 @@ struct VP8LDecoder {
// or'd bitset storing the transforms types.
uint32_t transforms_seen_;
- uint8_t *rescaler_memory; // Working memory for rescaling work.
- WebPRescaler *rescaler; // Common rescaler for all channels.
+ uint8_t* rescaler_memory; // Working memory for rescaling work.
+ WebPRescaler* rescaler; // Common rescaler for all channels.
};
//------------------------------------------------------------------------------
@@ -132,4 +132,4 @@ void VP8LDelete(VP8LDecoder* const dec);
} // extern "C"
#endif
-#endif /* WEBP_DEC_VP8LI_DEC_H_ */
+#endif // WEBP_DEC_VP8LI_DEC_H_
diff -up libwebp-1.0.0/src/utils/huffman_utils.c.old libwebp-1.0.0/src/utils/huffman_utils.c
--- libwebp-1.0.0/src/utils/huffman_utils.c.old 2018-04-21 05:04:55.000000000 +0200
+++ libwebp-1.0.0/src/utils/huffman_utils.c 2023-09-15 10:54:47.047025920 +0200
@@ -91,7 +91,8 @@ static int BuildHuffmanTable(HuffmanCode
assert(code_lengths_size != 0);
assert(code_lengths != NULL);
- assert(root_table != NULL);
+ assert((root_table != NULL && sorted != NULL) ||
+ (root_table == NULL && sorted == NULL));
assert(root_bits > 0);
// Build histogram of code lengths.
@@ -120,16 +121,22 @@ static int BuildHuffmanTable(HuffmanCode
for (symbol = 0; symbol < code_lengths_size; ++symbol) {
const int symbol_code_length = code_lengths[symbol];
if (code_lengths[symbol] > 0) {
- sorted[offset[symbol_code_length]++] = symbol;
+ if (sorted != NULL) {
+ sorted[offset[symbol_code_length]++] = symbol;
+ } else {
+ offset[symbol_code_length]++;
+ }
}
}
// Special case code with only one value.
if (offset[MAX_ALLOWED_CODE_LENGTH] == 1) {
- HuffmanCode code;
- code.bits = 0;
- code.value = (uint16_t)sorted[0];
- ReplicateValue(table, 1, total_size, code);
+ if (sorted != NULL) {
+ HuffmanCode code;
+ code.bits = 0;
+ code.value = (uint16_t)sorted[0];
+ ReplicateValue(table, 1, total_size, code);
+ }
return total_size;
}
@@ -151,6 +158,7 @@ static int BuildHuffmanTable(HuffmanCode
if (num_open < 0) {
return 0;
}
+ if (root_table == NULL) continue;
for (; count[len] > 0; --count[len]) {
HuffmanCode code;
code.bits = (uint8_t)len;
@@ -172,17 +180,21 @@ static int BuildHuffmanTable(HuffmanCode
for (; count[len] > 0; --count[len]) {
HuffmanCode code;
if ((key & mask) != low) {
- table += table_size;
+ if (root_table != NULL) table += table_size;
table_bits = NextTableBitSize(count, len, root_bits);
table_size = 1 << table_bits;
total_size += table_size;
low = key & mask;
- root_table[low].bits = (uint8_t)(table_bits + root_bits);
- root_table[low].value = (uint16_t)((table - root_table) - low);
+ if (root_table != NULL) {
+ root_table[low].bits = (uint8_t)(table_bits + root_bits);
+ root_table[low].value = (uint16_t)((table - root_table) - low);
+ }
+ }
+ if (root_table != NULL) {
+ code.bits = (uint8_t)(len - root_bits);
+ code.value = (uint16_t)sorted[symbol++];
+ ReplicateValue(&table[key >> root_bits], step, table_size, code);
}
- code.bits = (uint8_t)(len - root_bits);
- code.value = (uint16_t)sorted[symbol++];
- ReplicateValue(&table[key >> root_bits], step, table_size, code);
key = GetNextKey(key, len);
}
}
@@ -202,22 +214,83 @@ static int BuildHuffmanTable(HuffmanCode
((1 << MAX_CACHE_BITS) + NUM_LITERAL_CODES + NUM_LENGTH_CODES)
// Cut-off value for switching between heap and stack allocation.
#define SORTED_SIZE_CUTOFF 512
-int VP8LBuildHuffmanTable(HuffmanCode* const root_table, int root_bits,
+int VP8LBuildHuffmanTable(HuffmanTables* const root_table, int root_bits,
const int code_lengths[], int code_lengths_size) {
- int total_size;
+ const int total_size =
+ BuildHuffmanTable(NULL, root_bits, code_lengths, code_lengths_size, NULL);
assert(code_lengths_size <= MAX_CODE_LENGTHS_SIZE);
+ if (total_size == 0 || root_table == NULL) return total_size;
+
+ if (root_table->curr_segment->curr_table + total_size >=
+ root_table->curr_segment->start + root_table->curr_segment->size) {
+ // If 'root_table' does not have enough memory, allocate a new segment.
+ // The available part of root_table->curr_segment is left unused because we
+ // need a contiguous buffer.
+ const int segment_size = root_table->curr_segment->size;
+ struct HuffmanTablesSegment* next =
+ (HuffmanTablesSegment*)WebPSafeMalloc(1, sizeof(*next));
+ if (next == NULL) return 0;
+ // Fill the new segment.
+ // We need at least 'total_size' but if that value is small, it is better to
+ // allocate a big chunk to prevent more allocations later. 'segment_size' is
+ // therefore chosen (any other arbitrary value could be chosen).
+ next->size = total_size > segment_size ? total_size : segment_size;
+ next->start =
+ (HuffmanCode*)WebPSafeMalloc(next->size, sizeof(*next->start));
+ if (next->start == NULL) {
+ WebPSafeFree(next);
+ return 0;
+ }
+ next->curr_table = next->start;
+ next->next = NULL;
+ // Point to the new segment.
+ root_table->curr_segment->next = next;
+ root_table->curr_segment = next;
+ }
if (code_lengths_size <= SORTED_SIZE_CUTOFF) {
// use local stack-allocated array.
uint16_t sorted[SORTED_SIZE_CUTOFF];
- total_size = BuildHuffmanTable(root_table, root_bits,
- code_lengths, code_lengths_size, sorted);
- } else { // rare case. Use heap allocation.
+ BuildHuffmanTable(root_table->curr_segment->curr_table, root_bits,
+ code_lengths, code_lengths_size, sorted);
+ } else { // rare case. Use heap allocation.
uint16_t* const sorted =
(uint16_t*)WebPSafeMalloc(code_lengths_size, sizeof(*sorted));
if (sorted == NULL) return 0;
- total_size = BuildHuffmanTable(root_table, root_bits,
- code_lengths, code_lengths_size, sorted);
+ BuildHuffmanTable(root_table->curr_segment->curr_table, root_bits,
+ code_lengths, code_lengths_size, sorted);
WebPSafeFree(sorted);
}
return total_size;
}
+
+int VP8LHuffmanTablesAllocate(int size, HuffmanTables* huffman_tables) {
+ // Have 'segment' point to the first segment for now, 'root'.
+ HuffmanTablesSegment* const root = &huffman_tables->root;
+ huffman_tables->curr_segment = root;
+ // Allocate root.
+ root->start = (HuffmanCode*)WebPSafeMalloc(size, sizeof(*root->start));
+ if (root->start == NULL) return 0;
+ root->curr_table = root->start;
+ root->next = NULL;
+ root->size = size;
+ return 1;
+}
+
+void VP8LHuffmanTablesDeallocate(HuffmanTables* const huffman_tables) {
+ HuffmanTablesSegment *current, *next;
+ if (huffman_tables == NULL) return;
+ // Free the root node.
+ current = &huffman_tables->root;
+ next = current->next;
+ WebPSafeFree(current->start);
+ current->start = NULL;
+ current->next = NULL;
+ current = next;
+ // Free the following nodes.
+ while (current != NULL) {
+ next = current->next;
+ WebPSafeFree(current->start);
+ WebPSafeFree(current);
+ current = next;
+ }
+}
diff -up libwebp-1.0.0/src/utils/huffman_utils.h.old libwebp-1.0.0/src/utils/huffman_utils.h
--- libwebp-1.0.0/src/utils/huffman_utils.h.old 2018-04-21 05:04:55.000000000 +0200
+++ libwebp-1.0.0/src/utils/huffman_utils.h 2023-09-15 10:54:47.047025920 +0200
@@ -43,6 +43,29 @@ typedef struct {
// or non-literal symbol otherwise
} HuffmanCode32;
+// Contiguous memory segment of HuffmanCodes.
+typedef struct HuffmanTablesSegment {
+ HuffmanCode* start;
+ // Pointer to where we are writing into the segment. Starts at 'start' and
+ // cannot go beyond 'start' + 'size'.
+ HuffmanCode* curr_table;
+ // Pointer to the next segment in the chain.
+ struct HuffmanTablesSegment* next;
+ int size;
+} HuffmanTablesSegment;
+
+// Chained memory segments of HuffmanCodes.
+typedef struct HuffmanTables {
+ HuffmanTablesSegment root;
+ // Currently processed segment. At first, this is 'root'.
+ HuffmanTablesSegment* curr_segment;
+} HuffmanTables;
+
+// Allocates a HuffmanTables with 'size' contiguous HuffmanCodes. Returns 0 on
+// memory allocation error, 1 otherwise.
+int VP8LHuffmanTablesAllocate(int size, HuffmanTables* huffman_tables);
+void VP8LHuffmanTablesDeallocate(HuffmanTables* const huffman_tables);
+
#define HUFFMAN_PACKED_BITS 6
#define HUFFMAN_PACKED_TABLE_SIZE (1u << HUFFMAN_PACKED_BITS)
@@ -78,7 +101,7 @@ void VP8LHtreeGroupsFree(HTreeGroup* con
// the huffman table.
// Returns built table size or 0 in case of error (invalid tree or
// memory error).
-int VP8LBuildHuffmanTable(HuffmanCode* const root_table, int root_bits,
+int VP8LBuildHuffmanTable(HuffmanTables* const root_table, int root_bits,
const int code_lengths[], int code_lengths_size);
#ifdef __cplusplus
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