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-rw-r--r--media/libwebp/src/dec/vp8l_dec.c1757
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diff --git a/media/libwebp/src/dec/vp8l_dec.c b/media/libwebp/src/dec/vp8l_dec.c
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+++ b/media/libwebp/src/dec/vp8l_dec.c
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+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// main entry for the decoder
+//
+// Authors: Vikas Arora (vikaas.arora@gmail.com)
+// Jyrki Alakuijala (jyrki@google.com)
+
+#include <stdlib.h>
+
+#include "src/dec/alphai_dec.h"
+#include "src/dec/vp8li_dec.h"
+#include "src/dsp/dsp.h"
+#include "src/dsp/lossless.h"
+#include "src/dsp/lossless_common.h"
+#include "src/dsp/yuv.h"
+#include "src/utils/endian_inl_utils.h"
+#include "src/utils/huffman_utils.h"
+#include "src/utils/utils.h"
+
+#define NUM_ARGB_CACHE_ROWS 16
+
+static const int kCodeLengthLiterals = 16;
+static const int kCodeLengthRepeatCode = 16;
+static const uint8_t kCodeLengthExtraBits[3] = { 2, 3, 7 };
+static const uint8_t kCodeLengthRepeatOffsets[3] = { 3, 3, 11 };
+
+// -----------------------------------------------------------------------------
+// Five Huffman codes are used at each meta code:
+// 1. green + length prefix codes + color cache codes,
+// 2. alpha,
+// 3. red,
+// 4. blue, and,
+// 5. distance prefix codes.
+typedef enum {
+ GREEN = 0,
+ RED = 1,
+ BLUE = 2,
+ ALPHA = 3,
+ DIST = 4
+} HuffIndex;
+
+static const uint16_t kAlphabetSize[HUFFMAN_CODES_PER_META_CODE] = {
+ NUM_LITERAL_CODES + NUM_LENGTH_CODES,
+ NUM_LITERAL_CODES, NUM_LITERAL_CODES, NUM_LITERAL_CODES,
+ NUM_DISTANCE_CODES
+};
+
+static const uint8_t kLiteralMap[HUFFMAN_CODES_PER_META_CODE] = {
+ 0, 1, 1, 1, 0
+};
+
+#define NUM_CODE_LENGTH_CODES 19
+static const uint8_t kCodeLengthCodeOrder[NUM_CODE_LENGTH_CODES] = {
+ 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
+};
+
+#define CODE_TO_PLANE_CODES 120
+static const uint8_t kCodeToPlane[CODE_TO_PLANE_CODES] = {
+ 0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a,
+ 0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a,
+ 0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b,
+ 0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03,
+ 0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c,
+ 0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e,
+ 0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b,
+ 0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f,
+ 0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b,
+ 0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41,
+ 0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f,
+ 0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70
+};
+
+// Memory needed for lookup tables of one Huffman tree group. Red, blue, alpha
+// and distance alphabets are constant (256 for red, blue and alpha, 40 for
+// distance) and lookup table sizes for them in worst case are 630 and 410
+// respectively. Size of green alphabet depends on color cache size and is equal
+// to 256 (green component values) + 24 (length prefix values)
+// + color_cache_size (between 0 and 2048).
+// All values computed for 8-bit first level lookup with Mark Adler's tool:
+// https://github.com/madler/zlib/blob/v1.2.5/examples/enough.c
+#define FIXED_TABLE_SIZE (630 * 3 + 410)
+static const uint16_t kTableSize[12] = {
+ FIXED_TABLE_SIZE + 654,
+ FIXED_TABLE_SIZE + 656,
+ FIXED_TABLE_SIZE + 658,
+ FIXED_TABLE_SIZE + 662,
+ FIXED_TABLE_SIZE + 670,
+ FIXED_TABLE_SIZE + 686,
+ FIXED_TABLE_SIZE + 718,
+ FIXED_TABLE_SIZE + 782,
+ FIXED_TABLE_SIZE + 912,
+ FIXED_TABLE_SIZE + 1168,
+ FIXED_TABLE_SIZE + 1680,
+ FIXED_TABLE_SIZE + 2704
+};
+
+static int DecodeImageStream(int xsize, int ysize,
+ int is_level0,
+ VP8LDecoder* const dec,
+ uint32_t** const decoded_data);
+
+//------------------------------------------------------------------------------
+
+int VP8LCheckSignature(const uint8_t* const data, size_t size) {
+ return (size >= VP8L_FRAME_HEADER_SIZE &&
+ data[0] == VP8L_MAGIC_BYTE &&
+ (data[4] >> 5) == 0); // version
+}
+
+static int ReadImageInfo(VP8LBitReader* const br,
+ int* const width, int* const height,
+ int* const has_alpha) {
+ if (VP8LReadBits(br, 8) != VP8L_MAGIC_BYTE) return 0;
+ *width = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1;
+ *height = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1;
+ *has_alpha = VP8LReadBits(br, 1);
+ if (VP8LReadBits(br, VP8L_VERSION_BITS) != 0) return 0;
+ return !br->eos_;
+}
+
+int VP8LGetInfo(const uint8_t* data, size_t data_size,
+ int* const width, int* const height, int* const has_alpha) {
+ if (data == NULL || data_size < VP8L_FRAME_HEADER_SIZE) {
+ return 0; // not enough data
+ } else if (!VP8LCheckSignature(data, data_size)) {
+ return 0; // bad signature
+ } else {
+ int w, h, a;
+ VP8LBitReader br;
+ VP8LInitBitReader(&br, data, data_size);
+ if (!ReadImageInfo(&br, &w, &h, &a)) {
+ return 0;
+ }
+ if (width != NULL) *width = w;
+ if (height != NULL) *height = h;
+ if (has_alpha != NULL) *has_alpha = a;
+ return 1;
+ }
+}
+
+//------------------------------------------------------------------------------
+
+static WEBP_INLINE int GetCopyDistance(int distance_symbol,
+ VP8LBitReader* const br) {
+ int extra_bits, offset;
+ if (distance_symbol < 4) {
+ return distance_symbol + 1;
+ }
+ extra_bits = (distance_symbol - 2) >> 1;
+ offset = (2 + (distance_symbol & 1)) << extra_bits;
+ return offset + VP8LReadBits(br, extra_bits) + 1;
+}
+
+static WEBP_INLINE int GetCopyLength(int length_symbol,
+ VP8LBitReader* const br) {
+ // Length and distance prefixes are encoded the same way.
+ return GetCopyDistance(length_symbol, br);
+}
+
+static WEBP_INLINE int PlaneCodeToDistance(int xsize, int plane_code) {
+ if (plane_code > CODE_TO_PLANE_CODES) {
+ return plane_code - CODE_TO_PLANE_CODES;
+ } else {
+ const int dist_code = kCodeToPlane[plane_code - 1];
+ const int yoffset = dist_code >> 4;
+ const int xoffset = 8 - (dist_code & 0xf);
+ const int dist = yoffset * xsize + xoffset;
+ return (dist >= 1) ? dist : 1; // dist<1 can happen if xsize is very small
+ }
+}
+
+//------------------------------------------------------------------------------
+// Decodes the next Huffman code from bit-stream.
+// VP8LFillBitWindow(br) needs to be called at minimum every second call
+// to ReadSymbol, in order to pre-fetch enough bits.
+static WEBP_INLINE int ReadSymbol(const HuffmanCode* table,
+ VP8LBitReader* const br) {
+ int nbits;
+ uint32_t val = VP8LPrefetchBits(br);
+ table += val & HUFFMAN_TABLE_MASK;
+ nbits = table->bits - HUFFMAN_TABLE_BITS;
+ if (nbits > 0) {
+ VP8LSetBitPos(br, br->bit_pos_ + HUFFMAN_TABLE_BITS);
+ val = VP8LPrefetchBits(br);
+ table += table->value;
+ table += val & ((1 << nbits) - 1);
+ }
+ VP8LSetBitPos(br, br->bit_pos_ + table->bits);
+ return table->value;
+}
+
+// Reads packed symbol depending on GREEN channel
+#define BITS_SPECIAL_MARKER 0x100 // something large enough (and a bit-mask)
+#define PACKED_NON_LITERAL_CODE 0 // must be < NUM_LITERAL_CODES
+static WEBP_INLINE int ReadPackedSymbols(const HTreeGroup* group,
+ VP8LBitReader* const br,
+ uint32_t* const dst) {
+ const uint32_t val = VP8LPrefetchBits(br) & (HUFFMAN_PACKED_TABLE_SIZE - 1);
+ const HuffmanCode32 code = group->packed_table[val];
+ assert(group->use_packed_table);
+ if (code.bits < BITS_SPECIAL_MARKER) {
+ VP8LSetBitPos(br, br->bit_pos_ + code.bits);
+ *dst = code.value;
+ return PACKED_NON_LITERAL_CODE;
+ } else {
+ VP8LSetBitPos(br, br->bit_pos_ + code.bits - BITS_SPECIAL_MARKER);
+ assert(code.value >= NUM_LITERAL_CODES);
+ return code.value;
+ }
+}
+
+static int AccumulateHCode(HuffmanCode hcode, int shift,
+ HuffmanCode32* const huff) {
+ huff->bits += hcode.bits;
+ huff->value |= (uint32_t)hcode.value << shift;
+ assert(huff->bits <= HUFFMAN_TABLE_BITS);
+ return hcode.bits;
+}
+
+static void BuildPackedTable(HTreeGroup* const htree_group) {
+ uint32_t code;
+ for (code = 0; code < HUFFMAN_PACKED_TABLE_SIZE; ++code) {
+ uint32_t bits = code;
+ HuffmanCode32* const huff = &htree_group->packed_table[bits];
+ HuffmanCode hcode = htree_group->htrees[GREEN][bits];
+ if (hcode.value >= NUM_LITERAL_CODES) {
+ huff->bits = hcode.bits + BITS_SPECIAL_MARKER;
+ huff->value = hcode.value;
+ } else {
+ huff->bits = 0;
+ huff->value = 0;
+ bits >>= AccumulateHCode(hcode, 8, huff);
+ bits >>= AccumulateHCode(htree_group->htrees[RED][bits], 16, huff);
+ bits >>= AccumulateHCode(htree_group->htrees[BLUE][bits], 0, huff);
+ bits >>= AccumulateHCode(htree_group->htrees[ALPHA][bits], 24, huff);
+ (void)bits;
+ }
+ }
+}
+
+static int ReadHuffmanCodeLengths(
+ VP8LDecoder* const dec, const int* const code_length_code_lengths,
+ int num_symbols, int* const code_lengths) {
+ int ok = 0;
+ VP8LBitReader* const br = &dec->br_;
+ int symbol;
+ int max_symbol;
+ int prev_code_len = DEFAULT_CODE_LENGTH;
+ HuffmanTables tables;
+
+ if (!VP8LHuffmanTablesAllocate(1 << LENGTHS_TABLE_BITS, &tables) ||
+ !VP8LBuildHuffmanTable(&tables, LENGTHS_TABLE_BITS,
+ code_length_code_lengths, NUM_CODE_LENGTH_CODES)) {
+ goto End;
+ }
+
+ if (VP8LReadBits(br, 1)) { // use length
+ const int length_nbits = 2 + 2 * VP8LReadBits(br, 3);
+ max_symbol = 2 + VP8LReadBits(br, length_nbits);
+ if (max_symbol > num_symbols) {
+ goto End;
+ }
+ } else {
+ max_symbol = num_symbols;
+ }
+
+ symbol = 0;
+ while (symbol < num_symbols) {
+ const HuffmanCode* p;
+ int code_len;
+ if (max_symbol-- == 0) break;
+ VP8LFillBitWindow(br);
+ 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) {
+ code_lengths[symbol++] = code_len;
+ if (code_len != 0) prev_code_len = code_len;
+ } else {
+ const int use_prev = (code_len == kCodeLengthRepeatCode);
+ const int slot = code_len - kCodeLengthLiterals;
+ const int extra_bits = kCodeLengthExtraBits[slot];
+ const int repeat_offset = kCodeLengthRepeatOffsets[slot];
+ int repeat = VP8LReadBits(br, extra_bits) + repeat_offset;
+ if (symbol + repeat > num_symbols) {
+ goto End;
+ } else {
+ const int length = use_prev ? prev_code_len : 0;
+ while (repeat-- > 0) code_lengths[symbol++] = length;
+ }
+ }
+ }
+ ok = 1;
+
+ End:
+ VP8LHuffmanTablesDeallocate(&tables);
+ if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+ return ok;
+}
+
+// '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,
+ HuffmanTables* const table) {
+ int ok = 0;
+ int size = 0;
+ VP8LBitReader* const br = &dec->br_;
+ const int simple_code = VP8LReadBits(br, 1);
+
+ memset(code_lengths, 0, alphabet_size * sizeof(*code_lengths));
+
+ if (simple_code) { // Read symbols, codes & code lengths directly.
+ const int num_symbols = VP8LReadBits(br, 1) + 1;
+ const int first_symbol_len_code = VP8LReadBits(br, 1);
+ // The first code is either 1 bit or 8 bit code.
+ int symbol = VP8LReadBits(br, (first_symbol_len_code == 0) ? 1 : 8);
+ code_lengths[symbol] = 1;
+ // The second code (if present), is always 8 bits long.
+ if (num_symbols == 2) {
+ symbol = VP8LReadBits(br, 8);
+ code_lengths[symbol] = 1;
+ }
+ ok = 1;
+ } else { // Decode Huffman-coded code lengths.
+ int i;
+ int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 };
+ const int num_codes = VP8LReadBits(br, 4) + 4;
+ if (num_codes > NUM_CODE_LENGTH_CODES) {
+ dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+ return 0;
+ }
+
+ for (i = 0; i < num_codes; ++i) {
+ code_length_code_lengths[kCodeLengthCodeOrder[i]] = VP8LReadBits(br, 3);
+ }
+ ok = ReadHuffmanCodeLengths(dec, code_length_code_lengths, alphabet_size,
+ code_lengths);
+ }
+
+ ok = ok && !br->eos_;
+ if (ok) {
+ size = VP8LBuildHuffmanTable(table, HUFFMAN_TABLE_BITS,
+ code_lengths, alphabet_size);
+ }
+ if (!ok || size == 0) {
+ dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+ return 0;
+ }
+ return size;
+}
+
+static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
+ int color_cache_bits, int allow_recursion) {
+ int i, j;
+ VP8LBitReader* const br = &dec->br_;
+ VP8LMetadata* const hdr = &dec->hdr_;
+ uint32_t* huffman_image = NULL;
+ HTreeGroup* htree_groups = NULL;
+ HuffmanTables* huffman_tables = &hdr->huffman_tables_;
+ int num_htree_groups = 1;
+ int num_htree_groups_max = 1;
+ int max_alphabet_size = 0;
+ int* code_lengths = NULL;
+ const int table_size = kTableSize[color_cache_bits];
+ 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;
+ const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision);
+ const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision);
+ const int huffman_pixs = huffman_xsize * huffman_ysize;
+ if (!DecodeImageStream(huffman_xsize, huffman_ysize, 0, dec,
+ &huffman_image)) {
+ goto Error;
+ }
+ hdr->huffman_subsample_bits_ = huffman_precision;
+ for (i = 0; i < huffman_pixs; ++i) {
+ // The huffman data is stored in red and green bytes.
+ const int group = (huffman_image[i] >> 8) & 0xffff;
+ huffman_image[i] = group;
+ if (group >= num_htree_groups_max) {
+ num_htree_groups_max = group + 1;
+ }
+ }
+ // Check the validity of num_htree_groups_max. If it seems too big, use a
+ // smaller value for later. This will prevent big memory allocations to end
+ // up with a bad bitstream anyway.
+ // The value of 1000 is totally arbitrary. We know that num_htree_groups_max
+ // is smaller than (1 << 16) and should be smaller than the number of pixels
+ // (though the format allows it to be bigger).
+ if (num_htree_groups_max > 1000 || num_htree_groups_max > xsize * ysize) {
+ // Create a mapping from the used indices to the minimal set of used
+ // values [0, num_htree_groups)
+ mapping = (int*)WebPSafeMalloc(num_htree_groups_max, sizeof(*mapping));
+ if (mapping == NULL) {
+ dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ goto Error;
+ }
+ // -1 means a value is unmapped, and therefore unused in the Huffman
+ // image.
+ memset(mapping, 0xff, num_htree_groups_max * sizeof(*mapping));
+ for (num_htree_groups = 0, i = 0; i < huffman_pixs; ++i) {
+ // Get the current mapping for the group and remap the Huffman image.
+ int* const mapped_group = &mapping[huffman_image[i]];
+ if (*mapped_group == -1) *mapped_group = num_htree_groups++;
+ huffman_image[i] = *mapped_group;
+ }
+ } else {
+ num_htree_groups = num_htree_groups_max;
+ }
+ }
+
+ if (br->eos_) goto Error;
+
+ // Find maximum alphabet size for the htree group.
+ 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;
+ }
+ if (max_alphabet_size < alphabet_size) {
+ max_alphabet_size = alphabet_size;
+ }
+ }
+
+ code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
+ sizeof(*code_lengths));
+ htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
+
+ if (htree_groups == NULL || code_lengths == NULL ||
+ !VP8LHuffmanTablesAllocate(num_htree_groups * table_size,
+ huffman_tables)) {
+ dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ goto Error;
+ }
+
+ for (i = 0; i < num_htree_groups_max; ++i) {
+ // 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;
+ }
+ }
+ } 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;
+ }
+ }
+ 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);
+ }
+ }
+ ok = 1;
+
+ // All OK. Finalize pointers.
+ hdr->huffman_image_ = huffman_image;
+ hdr->num_htree_groups_ = num_htree_groups;
+ hdr->htree_groups_ = htree_groups;
+
+ Error:
+ WebPSafeFree(code_lengths);
+ WebPSafeFree(mapping);
+ if (!ok) {
+ WebPSafeFree(huffman_image);
+ VP8LHuffmanTablesDeallocate(huffman_tables);
+ VP8LHtreeGroupsFree(htree_groups);
+ }
+ return ok;
+}
+
+//------------------------------------------------------------------------------
+// Scaling.
+
+#if !defined(WEBP_REDUCE_SIZE)
+static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) {
+ const int num_channels = 4;
+ const int in_width = io->mb_w;
+ const int out_width = io->scaled_width;
+ const int in_height = io->mb_h;
+ const int out_height = io->scaled_height;
+ const uint64_t work_size = 2 * num_channels * (uint64_t)out_width;
+ rescaler_t* work; // Rescaler work area.
+ const uint64_t scaled_data_size = (uint64_t)out_width;
+ uint32_t* scaled_data; // Temporary storage for scaled BGRA data.
+ const uint64_t memory_size = sizeof(*dec->rescaler) +
+ work_size * sizeof(*work) +
+ scaled_data_size * sizeof(*scaled_data);
+ uint8_t* memory = (uint8_t*)WebPSafeMalloc(memory_size, sizeof(*memory));
+ if (memory == NULL) {
+ dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ return 0;
+ }
+ assert(dec->rescaler_memory == NULL);
+ dec->rescaler_memory = memory;
+
+ dec->rescaler = (WebPRescaler*)memory;
+ memory += sizeof(*dec->rescaler);
+ work = (rescaler_t*)memory;
+ memory += work_size * sizeof(*work);
+ scaled_data = (uint32_t*)memory;
+
+ if (!WebPRescalerInit(dec->rescaler, in_width, in_height,
+ (uint8_t*)scaled_data, out_width, out_height,
+ 0, num_channels, work)) {
+ return 0;
+ }
+ return 1;
+}
+#endif // WEBP_REDUCE_SIZE
+
+//------------------------------------------------------------------------------
+// Export to ARGB
+
+#if !defined(WEBP_REDUCE_SIZE)
+
+// We have special "export" function since we need to convert from BGRA
+static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace,
+ int rgba_stride, uint8_t* const rgba) {
+ uint32_t* const src = (uint32_t*)rescaler->dst;
+ uint8_t* dst = rgba;
+ const int dst_width = rescaler->dst_width;
+ int num_lines_out = 0;
+ while (WebPRescalerHasPendingOutput(rescaler)) {
+ WebPRescalerExportRow(rescaler);
+ WebPMultARGBRow(src, dst_width, 1);
+ VP8LConvertFromBGRA(src, dst_width, colorspace, dst);
+ dst += rgba_stride;
+ ++num_lines_out;
+ }
+ return num_lines_out;
+}
+
+// Emit scaled rows.
+static int EmitRescaledRowsRGBA(const VP8LDecoder* const dec,
+ uint8_t* in, int in_stride, int mb_h,
+ uint8_t* const out, int out_stride) {
+ const WEBP_CSP_MODE colorspace = dec->output_->colorspace;
+ int num_lines_in = 0;
+ int num_lines_out = 0;
+ while (num_lines_in < mb_h) {
+ uint8_t* const row_in = in + (uint64_t)num_lines_in * in_stride;
+ uint8_t* const row_out = out + (uint64_t)num_lines_out * out_stride;
+ const int lines_left = mb_h - num_lines_in;
+ const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left);
+ int lines_imported;
+ assert(needed_lines > 0 && needed_lines <= lines_left);
+ WebPMultARGBRows(row_in, in_stride,
+ dec->rescaler->src_width, needed_lines, 0);
+ lines_imported =
+ WebPRescalerImport(dec->rescaler, lines_left, row_in, in_stride);
+ assert(lines_imported == needed_lines);
+ num_lines_in += lines_imported;
+ num_lines_out += Export(dec->rescaler, colorspace, out_stride, row_out);
+ }
+ return num_lines_out;
+}
+
+#endif // WEBP_REDUCE_SIZE
+
+// Emit rows without any scaling.
+static int EmitRows(WEBP_CSP_MODE colorspace,
+ const uint8_t* row_in, int in_stride,
+ int mb_w, int mb_h,
+ uint8_t* const out, int out_stride) {
+ int lines = mb_h;
+ uint8_t* row_out = out;
+ while (lines-- > 0) {
+ VP8LConvertFromBGRA((const uint32_t*)row_in, mb_w, colorspace, row_out);
+ row_in += in_stride;
+ row_out += out_stride;
+ }
+ return mb_h; // Num rows out == num rows in.
+}
+
+//------------------------------------------------------------------------------
+// Export to YUVA
+
+static void ConvertToYUVA(const uint32_t* const src, int width, int y_pos,
+ const WebPDecBuffer* const output) {
+ const WebPYUVABuffer* const buf = &output->u.YUVA;
+
+ // first, the luma plane
+ WebPConvertARGBToY(src, buf->y + y_pos * buf->y_stride, width);
+
+ // then U/V planes
+ {
+ uint8_t* const u = buf->u + (y_pos >> 1) * buf->u_stride;
+ uint8_t* const v = buf->v + (y_pos >> 1) * buf->v_stride;
+ // even lines: store values
+ // odd lines: average with previous values
+ WebPConvertARGBToUV(src, u, v, width, !(y_pos & 1));
+ }
+ // Lastly, store alpha if needed.
+ if (buf->a != NULL) {
+ uint8_t* const a = buf->a + y_pos * buf->a_stride;
+#if defined(WORDS_BIGENDIAN)
+ WebPExtractAlpha((uint8_t*)src + 0, 0, width, 1, a, 0);
+#else
+ WebPExtractAlpha((uint8_t*)src + 3, 0, width, 1, a, 0);
+#endif
+ }
+}
+
+static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) {
+ WebPRescaler* const rescaler = dec->rescaler;
+ uint32_t* const src = (uint32_t*)rescaler->dst;
+ const int dst_width = rescaler->dst_width;
+ int num_lines_out = 0;
+ while (WebPRescalerHasPendingOutput(rescaler)) {
+ WebPRescalerExportRow(rescaler);
+ WebPMultARGBRow(src, dst_width, 1);
+ ConvertToYUVA(src, dst_width, y_pos, dec->output_);
+ ++y_pos;
+ ++num_lines_out;
+ }
+ return num_lines_out;
+}
+
+static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec,
+ uint8_t* in, int in_stride, int mb_h) {
+ int num_lines_in = 0;
+ int y_pos = dec->last_out_row_;
+ while (num_lines_in < mb_h) {
+ const int lines_left = mb_h - num_lines_in;
+ const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left);
+ int lines_imported;
+ WebPMultARGBRows(in, in_stride, dec->rescaler->src_width, needed_lines, 0);
+ lines_imported =
+ WebPRescalerImport(dec->rescaler, lines_left, in, in_stride);
+ assert(lines_imported == needed_lines);
+ num_lines_in += lines_imported;
+ in += needed_lines * in_stride;
+ y_pos += ExportYUVA(dec, y_pos);
+ }
+ return y_pos;
+}
+
+static int EmitRowsYUVA(const VP8LDecoder* const dec,
+ const uint8_t* in, int in_stride,
+ int mb_w, int num_rows) {
+ int y_pos = dec->last_out_row_;
+ while (num_rows-- > 0) {
+ ConvertToYUVA((const uint32_t*)in, mb_w, y_pos, dec->output_);
+ in += in_stride;
+ ++y_pos;
+ }
+ return y_pos;
+}
+
+//------------------------------------------------------------------------------
+// Cropping.
+
+// Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and
+// crop options. Also updates the input data pointer, so that it points to the
+// start of the cropped window. Note that pixels are in ARGB format even if
+// 'in_data' is uint8_t*.
+// Returns true if the crop window is not empty.
+static int SetCropWindow(VP8Io* const io, int y_start, int y_end,
+ uint8_t** const in_data, int pixel_stride) {
+ assert(y_start < y_end);
+ assert(io->crop_left < io->crop_right);
+ if (y_end > io->crop_bottom) {
+ y_end = io->crop_bottom; // make sure we don't overflow on last row.
+ }
+ if (y_start < io->crop_top) {
+ const int delta = io->crop_top - y_start;
+ y_start = io->crop_top;
+ *in_data += delta * pixel_stride;
+ }
+ if (y_start >= y_end) return 0; // Crop window is empty.
+
+ *in_data += io->crop_left * sizeof(uint32_t);
+
+ io->mb_y = y_start - io->crop_top;
+ io->mb_w = io->crop_right - io->crop_left;
+ io->mb_h = y_end - y_start;
+ return 1; // Non-empty crop window.
+}
+
+//------------------------------------------------------------------------------
+
+static WEBP_INLINE int GetMetaIndex(
+ const uint32_t* const image, int xsize, int bits, int x, int y) {
+ if (bits == 0) return 0;
+ return image[xsize * (y >> bits) + (x >> bits)];
+}
+
+static WEBP_INLINE HTreeGroup* GetHtreeGroupForPos(VP8LMetadata* const hdr,
+ int x, int y) {
+ const int meta_index = GetMetaIndex(hdr->huffman_image_, hdr->huffman_xsize_,
+ hdr->huffman_subsample_bits_, x, y);
+ assert(meta_index < hdr->num_htree_groups_);
+ return hdr->htree_groups_ + meta_index;
+}
+
+//------------------------------------------------------------------------------
+// Main loop, with custom row-processing function
+
+typedef void (*ProcessRowsFunc)(VP8LDecoder* const dec, int row);
+
+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 end_row = start_row + num_rows;
+ const uint32_t* rows_in = rows;
+ uint32_t* const rows_out = dec->argb_cache_;
+
+ // Inverse transforms.
+ while (n-- > 0) {
+ VP8LTransform* const transform = &dec->transforms_[n];
+ VP8LInverseTransform(transform, start_row, end_row, rows_in, rows_out);
+ rows_in = rows_out;
+ }
+ if (rows_in != rows_out) {
+ // No transform called, hence just copy.
+ memcpy(rows_out, rows_in, cache_pixs * sizeof(*rows_out));
+ }
+}
+
+// Processes (transforms, scales & color-converts) the rows decoded after the
+// last call.
+static void ProcessRows(VP8LDecoder* const dec, int row) {
+ const uint32_t* const rows = dec->pixels_ + dec->width_ * dec->last_row_;
+ const int num_rows = row - dec->last_row_;
+
+ assert(row <= dec->io_->crop_bottom);
+ // We can't process more than NUM_ARGB_CACHE_ROWS at a time (that's the size
+ // of argb_cache_), but we currently don't need more than that.
+ assert(num_rows <= NUM_ARGB_CACHE_ROWS);
+ if (num_rows > 0) { // Emit output.
+ 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, dec->last_row_, num_rows, rows);
+ if (!SetCropWindow(io, dec->last_row_, row, &rows_data, in_stride)) {
+ // Nothing to output (this time).
+ } else {
+ const WebPDecBuffer* const output = dec->output_;
+ if (WebPIsRGBMode(output->colorspace)) { // convert to RGBA
+ const WebPRGBABuffer* const buf = &output->u.RGBA;
+ uint8_t* const rgba =
+ buf->rgba + (int64_t)dec->last_out_row_ * buf->stride;
+ const int num_rows_out =
+#if !defined(WEBP_REDUCE_SIZE)
+ io->use_scaling ?
+ EmitRescaledRowsRGBA(dec, rows_data, in_stride, io->mb_h,
+ rgba, buf->stride) :
+#endif // WEBP_REDUCE_SIZE
+ EmitRows(output->colorspace, rows_data, in_stride,
+ io->mb_w, io->mb_h, rgba, buf->stride);
+ // Update 'last_out_row_'.
+ dec->last_out_row_ += num_rows_out;
+ } else { // convert to YUVA
+ dec->last_out_row_ = io->use_scaling ?
+ EmitRescaledRowsYUVA(dec, rows_data, in_stride, io->mb_h) :
+ EmitRowsYUVA(dec, rows_data, in_stride, io->mb_w, io->mb_h);
+ }
+ assert(dec->last_out_row_ <= output->height);
+ }
+ }
+
+ // Update 'last_row_'.
+ dec->last_row_ = row;
+ assert(dec->last_row_ <= dec->height_);
+}
+
+// Row-processing for the special case when alpha data contains only one
+// transform (color indexing), and trivial non-green literals.
+static int Is8bOptimizable(const VP8LMetadata* const hdr) {
+ int i;
+ if (hdr->color_cache_size_ > 0) return 0;
+ // When the Huffman tree contains only one symbol, we can skip the
+ // call to ReadSymbol() for red/blue/alpha channels.
+ for (i = 0; i < hdr->num_htree_groups_; ++i) {
+ HuffmanCode** const htrees = hdr->htree_groups_[i].htrees;
+ if (htrees[RED][0].bits > 0) return 0;
+ if (htrees[BLUE][0].bits > 0) return 0;
+ if (htrees[ALPHA][0].bits > 0) return 0;
+ }
+ return 1;
+}
+
+static void AlphaApplyFilter(ALPHDecoder* const alph_dec,
+ int first_row, int last_row,
+ uint8_t* out, int stride) {
+ if (alph_dec->filter_ != WEBP_FILTER_NONE) {
+ int y;
+ const uint8_t* prev_line = alph_dec->prev_line_;
+ assert(WebPUnfilters[alph_dec->filter_] != NULL);
+ for (y = first_row; y < last_row; ++y) {
+ WebPUnfilters[alph_dec->filter_](prev_line, out, out, stride);
+ prev_line = out;
+ out += stride;
+ }
+ alph_dec->prev_line_ = prev_line;
+ }
+}
+
+static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int last_row) {
+ // For vertical and gradient filtering, we need to decode the part above the
+ // crop_top row, in order to have the correct spatial predictors.
+ ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
+ const int top_row =
+ (alph_dec->filter_ == WEBP_FILTER_NONE ||
+ alph_dec->filter_ == WEBP_FILTER_HORIZONTAL) ? dec->io_->crop_top
+ : dec->last_row_;
+ const int first_row = (dec->last_row_ < top_row) ? top_row : dec->last_row_;
+ assert(last_row <= dec->io_->crop_bottom);
+ if (last_row > first_row) {
+ // Special method for paletted alpha data. We only process the cropped area.
+ const int width = dec->io_->width;
+ uint8_t* out = alph_dec->output_ + width * first_row;
+ const uint8_t* const in =
+ (uint8_t*)dec->pixels_ + dec->width_ * first_row;
+ VP8LTransform* const transform = &dec->transforms_[0];
+ assert(dec->next_transform_ == 1);
+ assert(transform->type_ == COLOR_INDEXING_TRANSFORM);
+ VP8LColorIndexInverseTransformAlpha(transform, first_row, last_row,
+ in, out);
+ AlphaApplyFilter(alph_dec, first_row, last_row, out, width);
+ }
+ dec->last_row_ = dec->last_out_row_ = last_row;
+}
+
+//------------------------------------------------------------------------------
+// Helper functions for fast pattern copy (8b and 32b)
+
+// cyclic rotation of pattern word
+static WEBP_INLINE uint32_t Rotate8b(uint32_t V) {
+#if defined(WORDS_BIGENDIAN)
+ return ((V & 0xff000000u) >> 24) | (V << 8);
+#else
+ return ((V & 0xffu) << 24) | (V >> 8);
+#endif
+}
+
+// copy 1, 2 or 4-bytes pattern
+static WEBP_INLINE void CopySmallPattern8b(const uint8_t* src, uint8_t* dst,
+ int length, uint32_t pattern) {
+ int i;
+ // align 'dst' to 4-bytes boundary. Adjust the pattern along the way.
+ while ((uintptr_t)dst & 3) {
+ *dst++ = *src++;
+ pattern = Rotate8b(pattern);
+ --length;
+ }
+ // Copy the pattern 4 bytes at a time.
+ for (i = 0; i < (length >> 2); ++i) {
+ ((uint32_t*)dst)[i] = pattern;
+ }
+ // Finish with left-overs. 'pattern' is still correctly positioned,
+ // so no Rotate8b() call is needed.
+ for (i <<= 2; i < length; ++i) {
+ dst[i] = src[i];
+ }
+}
+
+static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
+ const uint8_t* src = dst - dist;
+ if (length >= 8) {
+ uint32_t pattern = 0;
+ switch (dist) {
+ case 1:
+ pattern = src[0];
+#if defined(__arm__) || defined(_M_ARM) // arm doesn't like multiply that much
+ pattern |= pattern << 8;
+ pattern |= pattern << 16;
+#elif defined(WEBP_USE_MIPS_DSP_R2)
+ __asm__ volatile ("replv.qb %0, %0" : "+r"(pattern));
+#else
+ pattern = 0x01010101u * pattern;
+#endif
+ break;
+ case 2:
+#if !defined(WORDS_BIGENDIAN)
+ memcpy(&pattern, src, sizeof(uint16_t));
+#else
+ pattern = ((uint32_t)src[0] << 8) | src[1];
+#endif
+#if defined(__arm__) || defined(_M_ARM)
+ pattern |= pattern << 16;
+#elif defined(WEBP_USE_MIPS_DSP_R2)
+ __asm__ volatile ("replv.ph %0, %0" : "+r"(pattern));
+#else
+ pattern = 0x00010001u * pattern;
+#endif
+ break;
+ case 4:
+ memcpy(&pattern, src, sizeof(uint32_t));
+ break;
+ default:
+ goto Copy;
+ }
+ CopySmallPattern8b(src, dst, length, pattern);
+ return;
+ }
+ Copy:
+ if (dist >= length) { // no overlap -> use memcpy()
+ memcpy(dst, src, length * sizeof(*dst));
+ } else {
+ int i;
+ for (i = 0; i < length; ++i) dst[i] = src[i];
+ }
+}
+
+// copy pattern of 1 or 2 uint32_t's
+static WEBP_INLINE void CopySmallPattern32b(const uint32_t* src,
+ uint32_t* dst,
+ int length, uint64_t pattern) {
+ int i;
+ if ((uintptr_t)dst & 4) { // Align 'dst' to 8-bytes boundary.
+ *dst++ = *src++;
+ pattern = (pattern >> 32) | (pattern << 32);
+ --length;
+ }
+ assert(0 == ((uintptr_t)dst & 7));
+ for (i = 0; i < (length >> 1); ++i) {
+ ((uint64_t*)dst)[i] = pattern; // Copy the pattern 8 bytes at a time.
+ }
+ if (length & 1) { // Finish with left-over.
+ dst[i << 1] = src[i << 1];
+ }
+}
+
+static WEBP_INLINE void CopyBlock32b(uint32_t* const dst,
+ int dist, int length) {
+ const uint32_t* const src = dst - dist;
+ if (dist <= 2 && length >= 4 && ((uintptr_t)dst & 3) == 0) {
+ uint64_t pattern;
+ if (dist == 1) {
+ pattern = (uint64_t)src[0];
+ pattern |= pattern << 32;
+ } else {
+ memcpy(&pattern, src, sizeof(pattern));
+ }
+ CopySmallPattern32b(src, dst, length, pattern);
+ } else if (dist >= length) { // no overlap
+ memcpy(dst, src, length * sizeof(*dst));
+ } else {
+ int i;
+ for (i = 0; i < length; ++i) dst[i] = src[i];
+ }
+}
+
+//------------------------------------------------------------------------------
+
+static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
+ int width, int height, int last_row) {
+ int ok = 1;
+ int row = dec->last_pixel_ / width;
+ int col = dec->last_pixel_ % width;
+ VP8LBitReader* const br = &dec->br_;
+ VP8LMetadata* const hdr = &dec->hdr_;
+ int pos = dec->last_pixel_; // current position
+ const int end = width * height; // End of data
+ const int last = width * last_row; // Last pixel to decode
+ const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
+ const int mask = hdr->huffman_mask_;
+ const HTreeGroup* htree_group =
+ (pos < last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
+ assert(pos <= end);
+ assert(last_row <= height);
+ assert(Is8bOptimizable(hdr));
+
+ while (!br->eos_ && pos < last) {
+ int code;
+ // Only update when changing tile.
+ if ((col & mask) == 0) {
+ htree_group = GetHtreeGroupForPos(hdr, col, row);
+ }
+ assert(htree_group != NULL);
+ VP8LFillBitWindow(br);
+ code = ReadSymbol(htree_group->htrees[GREEN], br);
+ if (code < NUM_LITERAL_CODES) { // Literal
+ data[pos] = code;
+ ++pos;
+ ++col;
+ if (col >= width) {
+ col = 0;
+ ++row;
+ if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
+ ExtractPalettedAlphaRows(dec, row);
+ }
+ }
+ } else if (code < len_code_limit) { // Backward reference
+ int dist_code, dist;
+ const int length_sym = code - NUM_LITERAL_CODES;
+ const int length = GetCopyLength(length_sym, br);
+ const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br);
+ VP8LFillBitWindow(br);
+ dist_code = GetCopyDistance(dist_symbol, br);
+ dist = PlaneCodeToDistance(width, dist_code);
+ if (pos >= dist && end - pos >= length) {
+ CopyBlock8b(data + pos, dist, length);
+ } else {
+ ok = 0;
+ goto End;
+ }
+ pos += length;
+ col += length;
+ while (col >= width) {
+ col -= width;
+ ++row;
+ if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
+ ExtractPalettedAlphaRows(dec, row);
+ }
+ }
+ if (pos < last && (col & mask)) {
+ htree_group = GetHtreeGroupForPos(hdr, col, row);
+ }
+ } else { // Not reached
+ ok = 0;
+ goto End;
+ }
+ br->eos_ = VP8LIsEndOfStream(br);
+ }
+ // Process the remaining rows corresponding to last row-block.
+ ExtractPalettedAlphaRows(dec, row > last_row ? last_row : row);
+
+ End:
+ br->eos_ = VP8LIsEndOfStream(br);
+ if (!ok || (br->eos_ && pos < end)) {
+ ok = 0;
+ dec->status_ = br->eos_ ? VP8_STATUS_SUSPENDED
+ : VP8_STATUS_BITSTREAM_ERROR;
+ } else {
+ dec->last_pixel_ = pos;
+ }
+ return ok;
+}
+
+static void SaveState(VP8LDecoder* const dec, int last_pixel) {
+ assert(dec->incremental_);
+ dec->saved_br_ = dec->br_;
+ dec->saved_last_pixel_ = last_pixel;
+ if (dec->hdr_.color_cache_size_ > 0) {
+ VP8LColorCacheCopy(&dec->hdr_.color_cache_, &dec->hdr_.saved_color_cache_);
+ }
+}
+
+static void RestoreState(VP8LDecoder* const dec) {
+ assert(dec->br_.eos_);
+ dec->status_ = VP8_STATUS_SUSPENDED;
+ dec->br_ = dec->saved_br_;
+ dec->last_pixel_ = dec->saved_last_pixel_;
+ if (dec->hdr_.color_cache_size_ > 0) {
+ VP8LColorCacheCopy(&dec->hdr_.saved_color_cache_, &dec->hdr_.color_cache_);
+ }
+}
+
+#define SYNC_EVERY_N_ROWS 8 // minimum number of rows between check-points
+static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
+ int width, int height, int last_row,
+ ProcessRowsFunc process_func) {
+ int row = dec->last_pixel_ / width;
+ int col = dec->last_pixel_ % width;
+ VP8LBitReader* const br = &dec->br_;
+ VP8LMetadata* const hdr = &dec->hdr_;
+ uint32_t* src = data + dec->last_pixel_;
+ uint32_t* last_cached = src;
+ uint32_t* const src_end = data + width * height; // End of data
+ uint32_t* const src_last = data + width * last_row; // Last pixel to decode
+ const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
+ const int color_cache_limit = len_code_limit + hdr->color_cache_size_;
+ int next_sync_row = dec->incremental_ ? row : 1 << 24;
+ VP8LColorCache* const color_cache =
+ (hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL;
+ const int mask = hdr->huffman_mask_;
+ const HTreeGroup* htree_group =
+ (src < src_last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
+ assert(dec->last_row_ < last_row);
+ assert(src_last <= src_end);
+
+ while (src < src_last) {
+ int code;
+ if (row >= next_sync_row) {
+ SaveState(dec, (int)(src - data));
+ next_sync_row = row + SYNC_EVERY_N_ROWS;
+ }
+ // Only update when changing tile. Note we could use this test:
+ // if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed
+ // but that's actually slower and needs storing the previous col/row.
+ if ((col & mask) == 0) {
+ htree_group = GetHtreeGroupForPos(hdr, col, row);
+ }
+ assert(htree_group != NULL);
+ if (htree_group->is_trivial_code) {
+ *src = htree_group->literal_arb;
+ goto AdvanceByOne;
+ }
+ VP8LFillBitWindow(br);
+ if (htree_group->use_packed_table) {
+ code = ReadPackedSymbols(htree_group, br, src);
+ if (VP8LIsEndOfStream(br)) break;
+ if (code == PACKED_NON_LITERAL_CODE) goto AdvanceByOne;
+ } else {
+ code = ReadSymbol(htree_group->htrees[GREEN], br);
+ }
+ if (VP8LIsEndOfStream(br)) break;
+ if (code < NUM_LITERAL_CODES) { // Literal
+ if (htree_group->is_trivial_literal) {
+ *src = htree_group->literal_arb | (code << 8);
+ } else {
+ int red, blue, alpha;
+ red = ReadSymbol(htree_group->htrees[RED], br);
+ VP8LFillBitWindow(br);
+ blue = ReadSymbol(htree_group->htrees[BLUE], br);
+ alpha = ReadSymbol(htree_group->htrees[ALPHA], br);
+ if (VP8LIsEndOfStream(br)) break;
+ *src = ((uint32_t)alpha << 24) | (red << 16) | (code << 8) | blue;
+ }
+ AdvanceByOne:
+ ++src;
+ ++col;
+ if (col >= width) {
+ col = 0;
+ ++row;
+ if (process_func != NULL) {
+ if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
+ process_func(dec, row);
+ }
+ }
+ if (color_cache != NULL) {
+ while (last_cached < src) {
+ VP8LColorCacheInsert(color_cache, *last_cached++);
+ }
+ }
+ }
+ } else if (code < len_code_limit) { // Backward reference
+ int dist_code, dist;
+ const int length_sym = code - NUM_LITERAL_CODES;
+ const int length = GetCopyLength(length_sym, br);
+ const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br);
+ 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;
+ } else {
+ CopyBlock32b(src, dist, length);
+ }
+ src += length;
+ col += length;
+ while (col >= width) {
+ col -= width;
+ ++row;
+ if (process_func != NULL) {
+ if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
+ process_func(dec, row);
+ }
+ }
+ }
+ // Because of the check done above (before 'src' was incremented by
+ // 'length'), the following holds true.
+ assert(src <= src_end);
+ if (col & mask) htree_group = GetHtreeGroupForPos(hdr, col, row);
+ if (color_cache != NULL) {
+ while (last_cached < src) {
+ VP8LColorCacheInsert(color_cache, *last_cached++);
+ }
+ }
+ } else if (code < color_cache_limit) { // Color cache
+ const int key = code - len_code_limit;
+ assert(color_cache != NULL);
+ while (last_cached < src) {
+ VP8LColorCacheInsert(color_cache, *last_cached++);
+ }
+ *src = VP8LColorCacheLookup(color_cache, key);
+ goto AdvanceByOne;
+ } else { // Not reached
+ goto Error;
+ }
+ }
+
+ br->eos_ = VP8LIsEndOfStream(br);
+ // In incremental decoding:
+ // br->eos_ && src < src_last: if 'br' reached the end of the buffer and
+ // 'src_last' has not been reached yet, there is not enough data. 'dec' has to
+ // be reset until there is more data.
+ // !br->eos_ && src < src_last: this cannot happen as either the buffer is
+ // fully read, either enough has been read to reach 'src_last'.
+ // src >= src_last: 'src_last' is reached, all is fine. 'src' can actually go
+ // beyond 'src_last' in case the image is cropped and an LZ77 goes further.
+ // The buffer might have been enough or there is some left. 'br->eos_' does
+ // not matter.
+ assert(!dec->incremental_ || (br->eos_ && src < src_last) || src >= src_last);
+ if (dec->incremental_ && br->eos_ && src < src_last) {
+ RestoreState(dec);
+ } else if ((dec->incremental_ && src >= src_last) || !br->eos_) {
+ // Process the remaining rows corresponding to last row-block.
+ if (process_func != NULL) {
+ process_func(dec, row > last_row ? last_row : row);
+ }
+ dec->status_ = VP8_STATUS_OK;
+ dec->last_pixel_ = (int)(src - data); // end-of-scan marker
+ } else {
+ // if not incremental, and we are past the end of buffer (eos_=1), then this
+ // is a real bitstream error.
+ goto Error;
+ }
+ return 1;
+
+ Error:
+ dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+ return 0;
+}
+
+// -----------------------------------------------------------------------------
+// VP8LTransform
+
+static void ClearTransform(VP8LTransform* const transform) {
+ WebPSafeFree(transform->data_);
+ transform->data_ = NULL;
+}
+
+// For security reason, we need to remap the color map to span
+// the total possible bundled values, and not just the num_colors.
+static int ExpandColorMap(int num_colors, VP8LTransform* const transform) {
+ int i;
+ const int final_num_colors = 1 << (8 >> transform->bits_);
+ uint32_t* const new_color_map =
+ (uint32_t*)WebPSafeMalloc((uint64_t)final_num_colors,
+ sizeof(*new_color_map));
+ if (new_color_map == NULL) {
+ return 0;
+ } else {
+ uint8_t* const data = (uint8_t*)transform->data_;
+ uint8_t* const new_data = (uint8_t*)new_color_map;
+ new_color_map[0] = transform->data_[0];
+ for (i = 4; i < 4 * num_colors; ++i) {
+ // Equivalent to VP8LAddPixels(), on a byte-basis.
+ new_data[i] = (data[i] + new_data[i - 4]) & 0xff;
+ }
+ for (; i < 4 * final_num_colors; ++i) {
+ new_data[i] = 0; // black tail.
+ }
+ WebPSafeFree(transform->data_);
+ transform->data_ = new_color_map;
+ }
+ return 1;
+}
+
+static int ReadTransform(int* const xsize, int const* ysize,
+ VP8LDecoder* const dec) {
+ int ok = 1;
+ VP8LBitReader* const br = &dec->br_;
+ VP8LTransform* transform = &dec->transforms_[dec->next_transform_];
+ const VP8LImageTransformType type =
+ (VP8LImageTransformType)VP8LReadBits(br, 2);
+
+ // Each transform type can only be present once in the stream.
+ if (dec->transforms_seen_ & (1U << type)) {
+ return 0; // Already there, let's not accept the second same transform.
+ }
+ dec->transforms_seen_ |= (1U << type);
+
+ transform->type_ = type;
+ transform->xsize_ = *xsize;
+ transform->ysize_ = *ysize;
+ transform->data_ = NULL;
+ ++dec->next_transform_;
+ assert(dec->next_transform_ <= NUM_TRANSFORMS);
+
+ switch (type) {
+ case PREDICTOR_TRANSFORM:
+ case CROSS_COLOR_TRANSFORM:
+ transform->bits_ = VP8LReadBits(br, 3) + 2;
+ ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_,
+ transform->bits_),
+ VP8LSubSampleSize(transform->ysize_,
+ transform->bits_),
+ 0, dec, &transform->data_);
+ break;
+ case COLOR_INDEXING_TRANSFORM: {
+ const int num_colors = VP8LReadBits(br, 8) + 1;
+ const int bits = (num_colors > 16) ? 0
+ : (num_colors > 4) ? 1
+ : (num_colors > 2) ? 2
+ : 3;
+ *xsize = VP8LSubSampleSize(transform->xsize_, bits);
+ transform->bits_ = bits;
+ ok = DecodeImageStream(num_colors, 1, 0, dec, &transform->data_);
+ ok = ok && ExpandColorMap(num_colors, transform);
+ break;
+ }
+ case SUBTRACT_GREEN_TRANSFORM:
+ break;
+ default:
+ assert(0); // can't happen
+ break;
+ }
+
+ return ok;
+}
+
+// -----------------------------------------------------------------------------
+// VP8LMetadata
+
+static void InitMetadata(VP8LMetadata* const hdr) {
+ assert(hdr != NULL);
+ memset(hdr, 0, sizeof(*hdr));
+}
+
+static void ClearMetadata(VP8LMetadata* const hdr) {
+ assert(hdr != NULL);
+
+ WebPSafeFree(hdr->huffman_image_);
+ VP8LHuffmanTablesDeallocate(&hdr->huffman_tables_);
+ VP8LHtreeGroupsFree(hdr->htree_groups_);
+ VP8LColorCacheClear(&hdr->color_cache_);
+ VP8LColorCacheClear(&hdr->saved_color_cache_);
+ InitMetadata(hdr);
+}
+
+// -----------------------------------------------------------------------------
+// VP8LDecoder
+
+VP8LDecoder* VP8LNew(void) {
+ VP8LDecoder* const dec = (VP8LDecoder*)WebPSafeCalloc(1ULL, sizeof(*dec));
+ if (dec == NULL) return NULL;
+ dec->status_ = VP8_STATUS_OK;
+ dec->state_ = READ_DIM;
+
+ VP8LDspInit(); // Init critical function pointers.
+
+ return dec;
+}
+
+void VP8LClear(VP8LDecoder* const dec) {
+ int i;
+ if (dec == NULL) return;
+ ClearMetadata(&dec->hdr_);
+
+ WebPSafeFree(dec->pixels_);
+ dec->pixels_ = NULL;
+ for (i = 0; i < dec->next_transform_; ++i) {
+ ClearTransform(&dec->transforms_[i]);
+ }
+ dec->next_transform_ = 0;
+ dec->transforms_seen_ = 0;
+
+ WebPSafeFree(dec->rescaler_memory);
+ dec->rescaler_memory = NULL;
+
+ dec->output_ = NULL; // leave no trace behind
+}
+
+void VP8LDelete(VP8LDecoder* const dec) {
+ if (dec != NULL) {
+ VP8LClear(dec);
+ WebPSafeFree(dec);
+ }
+}
+
+static void UpdateDecoder(VP8LDecoder* const dec, int width, int height) {
+ VP8LMetadata* const hdr = &dec->hdr_;
+ const int num_bits = hdr->huffman_subsample_bits_;
+ dec->width_ = width;
+ dec->height_ = height;
+
+ hdr->huffman_xsize_ = VP8LSubSampleSize(width, num_bits);
+ hdr->huffman_mask_ = (num_bits == 0) ? ~0 : (1 << num_bits) - 1;
+}
+
+static int DecodeImageStream(int xsize, int ysize,
+ int is_level0,
+ VP8LDecoder* const dec,
+ uint32_t** const decoded_data) {
+ int ok = 1;
+ int transform_xsize = xsize;
+ int transform_ysize = ysize;
+ VP8LBitReader* const br = &dec->br_;
+ VP8LMetadata* const hdr = &dec->hdr_;
+ uint32_t* data = NULL;
+ int color_cache_bits = 0;
+
+ // Read the transforms (may recurse).
+ if (is_level0) {
+ while (ok && VP8LReadBits(br, 1)) {
+ ok = ReadTransform(&transform_xsize, &transform_ysize, dec);
+ }
+ }
+
+ // Color cache
+ if (ok && VP8LReadBits(br, 1)) {
+ color_cache_bits = VP8LReadBits(br, 4);
+ ok = (color_cache_bits >= 1 && color_cache_bits <= MAX_CACHE_BITS);
+ if (!ok) {
+ dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+ goto End;
+ }
+ }
+
+ // Read the Huffman codes (may recurse).
+ ok = ok && ReadHuffmanCodes(dec, transform_xsize, transform_ysize,
+ color_cache_bits, is_level0);
+ if (!ok) {
+ dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+ goto End;
+ }
+
+ // Finish setting up the color-cache
+ if (color_cache_bits > 0) {
+ hdr->color_cache_size_ = 1 << color_cache_bits;
+ if (!VP8LColorCacheInit(&hdr->color_cache_, color_cache_bits)) {
+ dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ ok = 0;
+ goto End;
+ }
+ } else {
+ hdr->color_cache_size_ = 0;
+ }
+ UpdateDecoder(dec, transform_xsize, transform_ysize);
+
+ if (is_level0) { // level 0 complete
+ dec->state_ = READ_HDR;
+ goto End;
+ }
+
+ {
+ const uint64_t total_size = (uint64_t)transform_xsize * transform_ysize;
+ data = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*data));
+ if (data == NULL) {
+ dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ ok = 0;
+ goto End;
+ }
+ }
+
+ // Use the Huffman trees to decode the LZ77 encoded data.
+ ok = DecodeImageData(dec, data, transform_xsize, transform_ysize,
+ transform_ysize, NULL);
+ ok = ok && !br->eos_;
+
+ End:
+ if (!ok) {
+ WebPSafeFree(data);
+ ClearMetadata(hdr);
+ } else {
+ if (decoded_data != NULL) {
+ *decoded_data = data;
+ } else {
+ // We allocate image data in this function only for transforms. At level 0
+ // (that is: not the transforms), we shouldn't have allocated anything.
+ assert(data == NULL);
+ assert(is_level0);
+ }
+ dec->last_pixel_ = 0; // Reset for future DECODE_DATA_FUNC() calls.
+ if (!is_level0) ClearMetadata(hdr); // Clean up temporary data behind.
+ }
+ return ok;
+}
+
+//------------------------------------------------------------------------------
+// Allocate internal buffers dec->pixels_ and dec->argb_cache_.
+static int AllocateInternalBuffers32b(VP8LDecoder* const dec, int final_width) {
+ const uint64_t num_pixels = (uint64_t)dec->width_ * dec->height_;
+ // Scratch buffer corresponding to top-prediction row for transforming the
+ // first row in the row-blocks. Not needed for paletted alpha.
+ const uint64_t cache_top_pixels = (uint16_t)final_width;
+ // Scratch buffer for temporary BGRA storage. Not needed for paletted alpha.
+ const uint64_t cache_pixels = (uint64_t)final_width * NUM_ARGB_CACHE_ROWS;
+ const uint64_t total_num_pixels =
+ num_pixels + cache_top_pixels + cache_pixels;
+
+ assert(dec->width_ <= final_width);
+ dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint32_t));
+ if (dec->pixels_ == NULL) {
+ dec->argb_cache_ = NULL; // for soundness
+ dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ return 0;
+ }
+ dec->argb_cache_ = dec->pixels_ + num_pixels + cache_top_pixels;
+ return 1;
+}
+
+static int AllocateInternalBuffers8b(VP8LDecoder* const dec) {
+ const uint64_t total_num_pixels = (uint64_t)dec->width_ * dec->height_;
+ dec->argb_cache_ = NULL; // for soundness
+ dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint8_t));
+ if (dec->pixels_ == NULL) {
+ dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ return 0;
+ }
+ return 1;
+}
+
+//------------------------------------------------------------------------------
+
+// Special row-processing that only stores the alpha data.
+static void ExtractAlphaRows(VP8LDecoder* const dec, int last_row) {
+ int cur_row = dec->last_row_;
+ int num_rows = last_row - cur_row;
+ const uint32_t* in = dec->pixels_ + dec->width_ * cur_row;
+
+ assert(last_row <= dec->io_->crop_bottom);
+ while (num_rows > 0) {
+ const int num_rows_to_process =
+ (num_rows > NUM_ARGB_CACHE_ROWS) ? NUM_ARGB_CACHE_ROWS : num_rows;
+ // Extract alpha (which is stored in the green plane).
+ ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
+ uint8_t* const output = alph_dec->output_;
+ const int width = dec->io_->width; // the final width (!= dec->width_)
+ 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, 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);
+ num_rows -= num_rows_to_process;
+ in += num_rows_to_process * dec->width_;
+ cur_row += num_rows_to_process;
+ }
+ assert(cur_row == last_row);
+ dec->last_row_ = dec->last_out_row_ = last_row;
+}
+
+int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
+ const uint8_t* const data, size_t data_size) {
+ int ok = 0;
+ VP8LDecoder* dec = VP8LNew();
+
+ if (dec == NULL) return 0;
+
+ assert(alph_dec != NULL);
+
+ dec->width_ = alph_dec->width_;
+ dec->height_ = alph_dec->height_;
+ dec->io_ = &alph_dec->io_;
+ dec->io_->opaque = alph_dec;
+ dec->io_->width = alph_dec->width_;
+ dec->io_->height = alph_dec->height_;
+
+ dec->status_ = VP8_STATUS_OK;
+ VP8LInitBitReader(&dec->br_, data, data_size);
+
+ if (!DecodeImageStream(alph_dec->width_, alph_dec->height_, 1, dec, NULL)) {
+ goto Err;
+ }
+
+ // Special case: if alpha data uses only the color indexing transform and
+ // doesn't use color cache (a frequent case), we will use DecodeAlphaData()
+ // method that only needs allocation of 1 byte per pixel (alpha channel).
+ if (dec->next_transform_ == 1 &&
+ dec->transforms_[0].type_ == COLOR_INDEXING_TRANSFORM &&
+ Is8bOptimizable(&dec->hdr_)) {
+ alph_dec->use_8b_decode_ = 1;
+ ok = AllocateInternalBuffers8b(dec);
+ } else {
+ // Allocate internal buffers (note that dec->width_ may have changed here).
+ alph_dec->use_8b_decode_ = 0;
+ ok = AllocateInternalBuffers32b(dec, alph_dec->width_);
+ }
+
+ if (!ok) goto Err;
+
+ // Only set here, once we are sure it is valid (to avoid thread races).
+ alph_dec->vp8l_dec_ = dec;
+ return 1;
+
+ Err:
+ VP8LDelete(dec);
+ return 0;
+}
+
+int VP8LDecodeAlphaImageStream(ALPHDecoder* const alph_dec, int last_row) {
+ VP8LDecoder* const dec = alph_dec->vp8l_dec_;
+ assert(dec != NULL);
+ assert(last_row <= dec->height_);
+
+ if (dec->last_row_ >= last_row) {
+ return 1; // done
+ }
+
+ if (!alph_dec->use_8b_decode_) WebPInitAlphaProcessing();
+
+ // Decode (with special row processing).
+ return alph_dec->use_8b_decode_ ?
+ DecodeAlphaData(dec, (uint8_t*)dec->pixels_, dec->width_, dec->height_,
+ last_row) :
+ DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
+ last_row, ExtractAlphaRows);
+}
+
+//------------------------------------------------------------------------------
+
+int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) {
+ int width, height, has_alpha;
+
+ if (dec == NULL) return 0;
+ if (io == NULL) {
+ dec->status_ = VP8_STATUS_INVALID_PARAM;
+ return 0;
+ }
+
+ dec->io_ = io;
+ dec->status_ = VP8_STATUS_OK;
+ VP8LInitBitReader(&dec->br_, io->data, io->data_size);
+ if (!ReadImageInfo(&dec->br_, &width, &height, &has_alpha)) {
+ dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+ goto Error;
+ }
+ dec->state_ = READ_DIM;
+ io->width = width;
+ io->height = height;
+
+ if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Error;
+ return 1;
+
+ Error:
+ VP8LClear(dec);
+ assert(dec->status_ != VP8_STATUS_OK);
+ return 0;
+}
+
+int VP8LDecodeImage(VP8LDecoder* const dec) {
+ VP8Io* io = NULL;
+ WebPDecParams* params = NULL;
+
+ if (dec == NULL) return 0;
+
+ assert(dec->hdr_.huffman_tables_.root.start != NULL);
+ assert(dec->hdr_.htree_groups_ != NULL);
+ assert(dec->hdr_.num_htree_groups_ > 0);
+
+ io = dec->io_;
+ assert(io != NULL);
+ params = (WebPDecParams*)io->opaque;
+ assert(params != NULL);
+
+ // Initialization.
+ if (dec->state_ != READ_DATA) {
+ dec->output_ = params->output;
+ assert(dec->output_ != NULL);
+
+ if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) {
+ dec->status_ = VP8_STATUS_INVALID_PARAM;
+ goto Err;
+ }
+
+ if (!AllocateInternalBuffers32b(dec, io->width)) goto Err;
+
+#if !defined(WEBP_REDUCE_SIZE)
+ if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err;
+#else
+ if (io->use_scaling) {
+ dec->status_ = VP8_STATUS_INVALID_PARAM;
+ goto Err;
+ }
+#endif
+ if (io->use_scaling || WebPIsPremultipliedMode(dec->output_->colorspace)) {
+ // need the alpha-multiply functions for premultiplied output or rescaling
+ WebPInitAlphaProcessing();
+ }
+
+ if (!WebPIsRGBMode(dec->output_->colorspace)) {
+ WebPInitConvertARGBToYUV();
+ if (dec->output_->u.YUVA.a != NULL) WebPInitAlphaProcessing();
+ }
+ if (dec->incremental_) {
+ if (dec->hdr_.color_cache_size_ > 0 &&
+ dec->hdr_.saved_color_cache_.colors_ == NULL) {
+ if (!VP8LColorCacheInit(&dec->hdr_.saved_color_cache_,
+ dec->hdr_.color_cache_.hash_bits_)) {
+ dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ goto Err;
+ }
+ }
+ }
+ dec->state_ = READ_DATA;
+ }
+
+ // Decode.
+ if (!DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
+ io->crop_bottom, ProcessRows)) {
+ goto Err;
+ }
+
+ params->last_y = dec->last_out_row_;
+ return 1;
+
+ Err:
+ VP8LClear(dec);
+ assert(dec->status_ != VP8_STATUS_OK);
+ return 0;
+}
+
+//------------------------------------------------------------------------------