mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
synced 2024-09-08 02:22:16 +00:00
360 lines
14 KiB
Diff
360 lines
14 KiB
Diff
![]() |
From 20ceff7eb3ccb679bd299f3d481309e10cbf2616 Mon Sep 17 00:00:00 2001
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From: Vincent Rabaud <vrabaud@google.com>
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Date: Thu, 7 Sep 2023 21:16:03 +0200
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Subject: [PATCH] Fix OOB write in BuildHuffmanTable.
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First, BuildHuffmanTable is called to check if the data is valid.
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If it is and the table is not big enough, more memory is allocated.
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This will make sure that valid (but unoptimized because of unbalanced
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codes) streams are still decodable.
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Bug: chromium:1479274
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Change-Id: I31c36dbf3aa78d35ecf38706b50464fd3d375741
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(cherry picked from commit 902bc9190331343b2017211debcec8d2ab87e17a)
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(cherry picked from commit 2af26267cdfcb63a88e5c74a85927a12d6ca1d76)
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---
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src/dec/vp8l_dec.c | 46 ++++++++++---------
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src/dec/vp8li_dec.h | 2 +-
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src/utils/huffman_utils.c | 97 +++++++++++++++++++++++++++++++--------
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src/utils/huffman_utils.h | 27 +++++++++--
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4 files changed, 129 insertions(+), 43 deletions(-)
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diff --git a/src/dec/vp8l_dec.c b/src/dec/vp8l_dec.c
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index 2d603b4379..09a0eeccf1 100644
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--- a/src/dec/vp8l_dec.c
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+++ b/src/dec/vp8l_dec.c
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@@ -253,11 +253,11 @@ static int ReadHuffmanCodeLengths(
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int symbol;
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int max_symbol;
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int prev_code_len = DEFAULT_CODE_LENGTH;
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- HuffmanCode table[1 << LENGTHS_TABLE_BITS];
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+ HuffmanTables tables;
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- if (!VP8LBuildHuffmanTable(table, LENGTHS_TABLE_BITS,
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- code_length_code_lengths,
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- NUM_CODE_LENGTH_CODES)) {
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+ if (!VP8LHuffmanTablesAllocate(1 << LENGTHS_TABLE_BITS, &tables) ||
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+ !VP8LBuildHuffmanTable(&tables, LENGTHS_TABLE_BITS,
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+ code_length_code_lengths, NUM_CODE_LENGTH_CODES)) {
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goto End;
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}
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@@ -277,7 +277,7 @@ static int ReadHuffmanCodeLengths(
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int code_len;
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if (max_symbol-- == 0) break;
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VP8LFillBitWindow(br);
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- p = &table[VP8LPrefetchBits(br) & LENGTHS_TABLE_MASK];
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+ p = &tables.curr_segment->start[VP8LPrefetchBits(br) & LENGTHS_TABLE_MASK];
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VP8LSetBitPos(br, br->bit_pos_ + p->bits);
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code_len = p->value;
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if (code_len < kCodeLengthLiterals) {
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@@ -300,6 +300,7 @@ static int ReadHuffmanCodeLengths(
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ok = 1;
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End:
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+ VP8LHuffmanTablesDeallocate(&tables);
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if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
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return ok;
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}
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@@ -307,7 +308,8 @@ static int ReadHuffmanCodeLengths(
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// 'code_lengths' is pre-allocated temporary buffer, used for creating Huffman
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// tree.
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static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
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- int* const code_lengths, HuffmanCode* const table) {
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+ int* const code_lengths,
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+ HuffmanTables* const table) {
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int ok = 0;
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int size = 0;
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VP8LBitReader* const br = &dec->br_;
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@@ -362,8 +364,7 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
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VP8LMetadata* const hdr = &dec->hdr_;
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uint32_t* huffman_image = NULL;
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HTreeGroup* htree_groups = NULL;
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- HuffmanCode* huffman_tables = NULL;
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- HuffmanCode* huffman_table = NULL;
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+ HuffmanTables* huffman_tables = &hdr->huffman_tables_;
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int num_htree_groups = 1;
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int num_htree_groups_max = 1;
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int max_alphabet_size = 0;
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@@ -372,6 +373,10 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
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int* mapping = NULL;
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int ok = 0;
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+ // Check the table has been 0 initialized (through InitMetadata).
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+ assert(huffman_tables->root.start == NULL);
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+ assert(huffman_tables->curr_segment == NULL);
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+
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if (allow_recursion && VP8LReadBits(br, 1)) {
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// use meta Huffman codes.
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const int huffman_precision = VP8LReadBits(br, 3) + 2;
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@@ -434,16 +439,15 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
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code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
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sizeof(*code_lengths));
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- huffman_tables = (HuffmanCode*)WebPSafeMalloc(num_htree_groups * table_size,
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- sizeof(*huffman_tables));
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htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
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- if (htree_groups == NULL || code_lengths == NULL || huffman_tables == NULL) {
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+ if (htree_groups == NULL || code_lengths == NULL ||
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+ !VP8LHuffmanTablesAllocate(num_htree_groups * table_size,
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+ huffman_tables)) {
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dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
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goto Error;
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}
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- huffman_table = huffman_tables;
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for (i = 0; i < num_htree_groups_max; ++i) {
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// If the index "i" is unused in the Huffman image, just make sure the
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// coefficients are valid but do not store them.
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@@ -468,19 +472,20 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
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int max_bits = 0;
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for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
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int alphabet_size = kAlphabetSize[j];
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- htrees[j] = huffman_table;
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if (j == 0 && color_cache_bits > 0) {
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alphabet_size += (1 << color_cache_bits);
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}
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- size = ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_table);
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+ size =
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+ ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_tables);
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+ htrees[j] = huffman_tables->curr_segment->curr_table;
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if (size == 0) {
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goto Error;
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}
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if (is_trivial_literal && kLiteralMap[j] == 1) {
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- is_trivial_literal = (huffman_table->bits == 0);
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+ is_trivial_literal = (htrees[j]->bits == 0);
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}
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- total_size += huffman_table->bits;
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- huffman_table += size;
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+ total_size += htrees[j]->bits;
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+ huffman_tables->curr_segment->curr_table += size;
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if (j <= ALPHA) {
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int local_max_bits = code_lengths[0];
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int k;
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@@ -515,14 +520,13 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
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hdr->huffman_image_ = huffman_image;
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hdr->num_htree_groups_ = num_htree_groups;
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hdr->htree_groups_ = htree_groups;
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- hdr->huffman_tables_ = huffman_tables;
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Error:
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WebPSafeFree(code_lengths);
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WebPSafeFree(mapping);
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if (!ok) {
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WebPSafeFree(huffman_image);
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- WebPSafeFree(huffman_tables);
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+ VP8LHuffmanTablesDeallocate(huffman_tables);
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VP8LHtreeGroupsFree(htree_groups);
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}
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return ok;
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@@ -1353,7 +1357,7 @@ static void ClearMetadata(VP8LMetadata* const hdr) {
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assert(hdr != NULL);
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WebPSafeFree(hdr->huffman_image_);
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- WebPSafeFree(hdr->huffman_tables_);
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+ VP8LHuffmanTablesDeallocate(&hdr->huffman_tables_);
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VP8LHtreeGroupsFree(hdr->htree_groups_);
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VP8LColorCacheClear(&hdr->color_cache_);
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VP8LColorCacheClear(&hdr->saved_color_cache_);
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@@ -1669,7 +1673,7 @@ int VP8LDecodeImage(VP8LDecoder* const dec) {
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// Sanity checks.
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if (dec == NULL) return 0;
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- assert(dec->hdr_.huffman_tables_ != NULL);
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+ assert(dec->hdr_.huffman_tables_.root.start != NULL);
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assert(dec->hdr_.htree_groups_ != NULL);
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assert(dec->hdr_.num_htree_groups_ > 0);
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diff --git a/src/dec/vp8li_dec.h b/src/dec/vp8li_dec.h
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index 72b2e86120..32540a4b88 100644
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--- a/src/dec/vp8li_dec.h
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+++ b/src/dec/vp8li_dec.h
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@@ -51,7 +51,7 @@ typedef struct {
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uint32_t* huffman_image_;
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int num_htree_groups_;
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HTreeGroup* htree_groups_;
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- HuffmanCode* huffman_tables_;
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+ HuffmanTables huffman_tables_;
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} VP8LMetadata;
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typedef struct VP8LDecoder VP8LDecoder;
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diff --git a/src/utils/huffman_utils.c b/src/utils/huffman_utils.c
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index 0cba0fbb7d..9efd6283ac 100644
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--- a/src/utils/huffman_utils.c
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+++ b/src/utils/huffman_utils.c
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@@ -177,21 +177,24 @@ static int BuildHuffmanTable(HuffmanCode* const root_table, int root_bits,
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if (num_open < 0) {
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return 0;
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}
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- if (root_table == NULL) continue;
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for (; count[len] > 0; --count[len]) {
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HuffmanCode code;
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if ((key & mask) != low) {
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- table += table_size;
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+ if (root_table != NULL) table += table_size;
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table_bits = NextTableBitSize(count, len, root_bits);
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table_size = 1 << table_bits;
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total_size += table_size;
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low = key & mask;
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- root_table[low].bits = (uint8_t)(table_bits + root_bits);
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- root_table[low].value = (uint16_t)((table - root_table) - low);
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+ if (root_table != NULL) {
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+ root_table[low].bits = (uint8_t)(table_bits + root_bits);
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+ root_table[low].value = (uint16_t)((table - root_table) - low);
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+ }
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+ }
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+ if (root_table != NULL) {
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+ code.bits = (uint8_t)(len - root_bits);
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+ code.value = (uint16_t)sorted[symbol++];
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+ ReplicateValue(&table[key >> root_bits], step, table_size, code);
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}
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- code.bits = (uint8_t)(len - root_bits);
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- code.value = (uint16_t)sorted[symbol++];
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- ReplicateValue(&table[key >> root_bits], step, table_size, code);
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key = GetNextKey(key, len);
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}
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}
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@@ -211,25 +214,83 @@ static int BuildHuffmanTable(HuffmanCode* const root_table, int root_bits,
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((1 << MAX_CACHE_BITS) + NUM_LITERAL_CODES + NUM_LENGTH_CODES)
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// Cut-off value for switching between heap and stack allocation.
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#define SORTED_SIZE_CUTOFF 512
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-int VP8LBuildHuffmanTable(HuffmanCode* const root_table, int root_bits,
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+int VP8LBuildHuffmanTable(HuffmanTables* const root_table, int root_bits,
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const int code_lengths[], int code_lengths_size) {
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- int total_size;
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+ const int total_size =
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+ BuildHuffmanTable(NULL, root_bits, code_lengths, code_lengths_size, NULL);
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assert(code_lengths_size <= MAX_CODE_LENGTHS_SIZE);
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- if (root_table == NULL) {
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- total_size = BuildHuffmanTable(NULL, root_bits,
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- code_lengths, code_lengths_size, NULL);
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- } else if (code_lengths_size <= SORTED_SIZE_CUTOFF) {
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+ if (total_size == 0 || root_table == NULL) return total_size;
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+
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+ if (root_table->curr_segment->curr_table + total_size >=
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+ root_table->curr_segment->start + root_table->curr_segment->size) {
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+ // If 'root_table' does not have enough memory, allocate a new segment.
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+ // The available part of root_table->curr_segment is left unused because we
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+ // need a contiguous buffer.
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+ const int segment_size = root_table->curr_segment->size;
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+ struct HuffmanTablesSegment* next =
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+ (HuffmanTablesSegment*)WebPSafeMalloc(1, sizeof(*next));
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+ if (next == NULL) return 0;
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+ // Fill the new segment.
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+ // We need at least 'total_size' but if that value is small, it is better to
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+ // allocate a big chunk to prevent more allocations later. 'segment_size' is
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+ // therefore chosen (any other arbitrary value could be chosen).
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+ next->size = total_size > segment_size ? total_size : segment_size;
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+ next->start =
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+ (HuffmanCode*)WebPSafeMalloc(next->size, sizeof(*next->start));
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+ if (next->start == NULL) {
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+ WebPSafeFree(next);
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+ return 0;
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+ }
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+ next->curr_table = next->start;
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+ next->next = NULL;
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+ // Point to the new segment.
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+ root_table->curr_segment->next = next;
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+ root_table->curr_segment = next;
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+ }
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+ if (code_lengths_size <= SORTED_SIZE_CUTOFF) {
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// use local stack-allocated array.
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uint16_t sorted[SORTED_SIZE_CUTOFF];
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- total_size = BuildHuffmanTable(root_table, root_bits,
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- code_lengths, code_lengths_size, sorted);
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- } else { // rare case. Use heap allocation.
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+ BuildHuffmanTable(root_table->curr_segment->curr_table, root_bits,
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+ code_lengths, code_lengths_size, sorted);
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+ } else { // rare case. Use heap allocation.
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uint16_t* const sorted =
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(uint16_t*)WebPSafeMalloc(code_lengths_size, sizeof(*sorted));
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if (sorted == NULL) return 0;
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- total_size = BuildHuffmanTable(root_table, root_bits,
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- code_lengths, code_lengths_size, sorted);
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+ BuildHuffmanTable(root_table->curr_segment->curr_table, root_bits,
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+ code_lengths, code_lengths_size, sorted);
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WebPSafeFree(sorted);
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}
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return total_size;
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}
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+
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+int VP8LHuffmanTablesAllocate(int size, HuffmanTables* huffman_tables) {
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+ // Have 'segment' point to the first segment for now, 'root'.
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+ HuffmanTablesSegment* const root = &huffman_tables->root;
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+ huffman_tables->curr_segment = root;
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+ // Allocate root.
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+ root->start = (HuffmanCode*)WebPSafeMalloc(size, sizeof(*root->start));
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+ if (root->start == NULL) return 0;
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+ root->curr_table = root->start;
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+ root->next = NULL;
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+ root->size = size;
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+ return 1;
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+}
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+
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+void VP8LHuffmanTablesDeallocate(HuffmanTables* const huffman_tables) {
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+ HuffmanTablesSegment *current, *next;
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+ if (huffman_tables == NULL) return;
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+ // Free the root node.
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+ current = &huffman_tables->root;
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+ next = current->next;
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+ WebPSafeFree(current->start);
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+ current->start = NULL;
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+ current->next = NULL;
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+ current = next;
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+ // Free the following nodes.
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+ while (current != NULL) {
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+ next = current->next;
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+ WebPSafeFree(current->start);
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+ WebPSafeFree(current);
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+ current = next;
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+ }
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+}
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diff --git a/src/utils/huffman_utils.h b/src/utils/huffman_utils.h
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index 13b7ad1ac4..98415c5328 100644
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--- a/src/utils/huffman_utils.h
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+++ b/src/utils/huffman_utils.h
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@@ -43,6 +43,29 @@ typedef struct {
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// or non-literal symbol otherwise
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} HuffmanCode32;
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+// Contiguous memory segment of HuffmanCodes.
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+typedef struct HuffmanTablesSegment {
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+ HuffmanCode* start;
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+ // Pointer to where we are writing into the segment. Starts at 'start' and
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+ // cannot go beyond 'start' + 'size'.
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+ HuffmanCode* curr_table;
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+ // Pointer to the next segment in the chain.
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+ struct HuffmanTablesSegment* next;
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+ int size;
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+} HuffmanTablesSegment;
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+
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+// Chained memory segments of HuffmanCodes.
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+typedef struct HuffmanTables {
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+ HuffmanTablesSegment root;
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+ // Currently processed segment. At first, this is 'root'.
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+ HuffmanTablesSegment* curr_segment;
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+} HuffmanTables;
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+
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+// Allocates a HuffmanTables with 'size' contiguous HuffmanCodes. Returns 0 on
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+// memory allocation error, 1 otherwise.
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+int VP8LHuffmanTablesAllocate(int size, HuffmanTables* huffman_tables);
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+void VP8LHuffmanTablesDeallocate(HuffmanTables* const huffman_tables);
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+
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#define HUFFMAN_PACKED_BITS 6
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#define HUFFMAN_PACKED_TABLE_SIZE (1u << HUFFMAN_PACKED_BITS)
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@@ -78,9 +101,7 @@ void VP8LHtreeGroupsFree(HTreeGroup* const htree_groups);
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// the huffman table.
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// Returns built table size or 0 in case of error (invalid tree or
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// memory error).
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-// If root_table is NULL, it returns 0 if a lookup cannot be built, something
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-// > 0 otherwise (but not the table size).
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-int VP8LBuildHuffmanTable(HuffmanCode* const root_table, int root_bits,
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+int VP8LBuildHuffmanTable(HuffmanTables* const root_table, int root_bits,
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const int code_lengths[], int code_lengths_size);
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#ifdef __cplusplus
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