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1250 lines
46 KiB
C
1250 lines
46 KiB
C
// Copyright 2012 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// main entry for the decoder
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//
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// Authors: Vikas Arora (vikaas.arora@gmail.com)
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// Jyrki Alakuijala (jyrki@google.com)
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#include <stdio.h>
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#include <stdlib.h>
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#include "./vp8li.h"
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#include "../dsp/lossless.h"
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#include "../dsp/yuv.h"
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#include "../utils/huffman.h"
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#include "../utils/utils.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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#define NUM_ARGB_CACHE_ROWS 16
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static const int kCodeLengthLiterals = 16;
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static const int kCodeLengthRepeatCode = 16;
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static const int kCodeLengthExtraBits[3] = { 2, 3, 7 };
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static const int kCodeLengthRepeatOffsets[3] = { 3, 3, 11 };
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// -----------------------------------------------------------------------------
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// Five Huffman codes are used at each meta code:
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// 1. green + length prefix codes + color cache codes,
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// 2. alpha,
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// 3. red,
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// 4. blue, and,
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// 5. distance prefix codes.
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typedef enum {
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GREEN = 0,
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RED = 1,
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BLUE = 2,
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ALPHA = 3,
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DIST = 4
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} HuffIndex;
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static const uint16_t kAlphabetSize[HUFFMAN_CODES_PER_META_CODE] = {
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NUM_LITERAL_CODES + NUM_LENGTH_CODES,
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NUM_LITERAL_CODES, NUM_LITERAL_CODES, NUM_LITERAL_CODES,
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NUM_DISTANCE_CODES
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};
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#define NUM_CODE_LENGTH_CODES 19
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static const uint8_t kCodeLengthCodeOrder[NUM_CODE_LENGTH_CODES] = {
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17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
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};
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#define CODE_TO_PLANE_CODES 120
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static const uint8_t code_to_plane_lut[CODE_TO_PLANE_CODES] = {
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0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a,
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0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a,
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0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b,
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0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03,
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0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c,
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0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e,
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0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b,
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0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f,
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0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b,
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0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41,
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0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f,
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0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70
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};
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static int DecodeImageStream(int xsize, int ysize,
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int is_level0,
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VP8LDecoder* const dec,
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uint32_t** const decoded_data);
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//------------------------------------------------------------------------------
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int VP8LCheckSignature(const uint8_t* const data, size_t size) {
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return (size >= 1) && (data[0] == VP8L_MAGIC_BYTE);
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}
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static int ReadImageInfo(VP8LBitReader* const br,
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int* const width, int* const height,
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int* const has_alpha) {
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const uint8_t signature = VP8LReadBits(br, 8);
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if (!VP8LCheckSignature(&signature, 1)) {
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return 0;
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}
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*width = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1;
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*height = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1;
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*has_alpha = VP8LReadBits(br, 1);
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VP8LReadBits(br, VP8L_VERSION_BITS); // Read/ignore the version number.
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return 1;
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}
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int VP8LGetInfo(const uint8_t* data, size_t data_size,
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int* const width, int* const height, int* const has_alpha) {
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if (data == NULL || data_size < VP8L_FRAME_HEADER_SIZE) {
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return 0; // not enough data
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} else {
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int w, h, a;
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VP8LBitReader br;
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VP8LInitBitReader(&br, data, data_size);
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if (!ReadImageInfo(&br, &w, &h, &a)) {
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return 0;
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}
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if (width != NULL) *width = w;
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if (height != NULL) *height = h;
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if (has_alpha != NULL) *has_alpha = a;
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return 1;
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}
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}
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//------------------------------------------------------------------------------
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static WEBP_INLINE int GetCopyDistance(int distance_symbol,
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VP8LBitReader* const br) {
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int extra_bits, offset;
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if (distance_symbol < 4) {
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return distance_symbol + 1;
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}
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extra_bits = (distance_symbol - 2) >> 1;
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offset = (2 + (distance_symbol & 1)) << extra_bits;
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return offset + VP8LReadBits(br, extra_bits) + 1;
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}
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static WEBP_INLINE int GetCopyLength(int length_symbol,
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VP8LBitReader* const br) {
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// Length and distance prefixes are encoded the same way.
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return GetCopyDistance(length_symbol, br);
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}
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static WEBP_INLINE int PlaneCodeToDistance(int xsize, int plane_code) {
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if (plane_code > CODE_TO_PLANE_CODES) {
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return plane_code - CODE_TO_PLANE_CODES;
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} else {
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const int dist_code = code_to_plane_lut[plane_code - 1];
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const int yoffset = dist_code >> 4;
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const int xoffset = 8 - (dist_code & 0xf);
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const int dist = yoffset * xsize + xoffset;
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return (dist >= 1) ? dist : 1;
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}
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}
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//------------------------------------------------------------------------------
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// Decodes the next Huffman code from bit-stream.
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// FillBitWindow(br) needs to be called at minimum every second call
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// to ReadSymbol, in order to pre-fetch enough bits.
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static WEBP_INLINE int ReadSymbol(const HuffmanTree* tree,
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VP8LBitReader* const br) {
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const HuffmanTreeNode* node = tree->root_;
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int num_bits = 0;
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uint32_t bits = VP8LPrefetchBits(br);
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assert(node != NULL);
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while (!HuffmanTreeNodeIsLeaf(node)) {
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node = HuffmanTreeNextNode(node, bits & 1);
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bits >>= 1;
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++num_bits;
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}
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VP8LDiscardBits(br, num_bits);
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return node->symbol_;
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}
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static int ReadHuffmanCodeLengths(
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VP8LDecoder* const dec, const int* const code_length_code_lengths,
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int num_symbols, int* const code_lengths) {
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int ok = 0;
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VP8LBitReader* const br = &dec->br_;
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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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HuffmanTree tree;
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if (!HuffmanTreeBuildImplicit(&tree, code_length_code_lengths,
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NUM_CODE_LENGTH_CODES)) {
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dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
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return 0;
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}
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if (VP8LReadBits(br, 1)) { // use length
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const int length_nbits = 2 + 2 * VP8LReadBits(br, 3);
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max_symbol = 2 + VP8LReadBits(br, length_nbits);
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if (max_symbol > num_symbols) {
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dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
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goto End;
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}
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} else {
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max_symbol = num_symbols;
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}
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symbol = 0;
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while (symbol < num_symbols) {
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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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code_len = ReadSymbol(&tree, br);
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if (code_len < kCodeLengthLiterals) {
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code_lengths[symbol++] = code_len;
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if (code_len != 0) prev_code_len = code_len;
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} else {
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const int use_prev = (code_len == kCodeLengthRepeatCode);
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const int slot = code_len - kCodeLengthLiterals;
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const int extra_bits = kCodeLengthExtraBits[slot];
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const int repeat_offset = kCodeLengthRepeatOffsets[slot];
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int repeat = VP8LReadBits(br, extra_bits) + repeat_offset;
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if (symbol + repeat > num_symbols) {
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dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
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goto End;
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} else {
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const int length = use_prev ? prev_code_len : 0;
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while (repeat-- > 0) code_lengths[symbol++] = length;
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}
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}
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}
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ok = 1;
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End:
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HuffmanTreeRelease(&tree);
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return ok;
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}
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static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
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HuffmanTree* const tree) {
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int ok = 0;
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VP8LBitReader* const br = &dec->br_;
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const int simple_code = VP8LReadBits(br, 1);
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if (simple_code) { // Read symbols, codes & code lengths directly.
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int symbols[2];
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int codes[2];
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int code_lengths[2];
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const int num_symbols = VP8LReadBits(br, 1) + 1;
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const int first_symbol_len_code = VP8LReadBits(br, 1);
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// The first code is either 1 bit or 8 bit code.
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symbols[0] = VP8LReadBits(br, (first_symbol_len_code == 0) ? 1 : 8);
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codes[0] = 0;
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code_lengths[0] = num_symbols - 1;
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// The second code (if present), is always 8 bit long.
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if (num_symbols == 2) {
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symbols[1] = VP8LReadBits(br, 8);
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codes[1] = 1;
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code_lengths[1] = num_symbols - 1;
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}
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ok = HuffmanTreeBuildExplicit(tree, code_lengths, codes, symbols,
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alphabet_size, num_symbols);
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} else { // Decode Huffman-coded code lengths.
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int* code_lengths = NULL;
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int i;
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int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 };
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const int num_codes = VP8LReadBits(br, 4) + 4;
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if (num_codes > NUM_CODE_LENGTH_CODES) {
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dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
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return 0;
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}
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code_lengths =
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(int*)WebPSafeCalloc((uint64_t)alphabet_size, sizeof(*code_lengths));
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if (code_lengths == NULL) {
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dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
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return 0;
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}
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for (i = 0; i < num_codes; ++i) {
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code_length_code_lengths[kCodeLengthCodeOrder[i]] = VP8LReadBits(br, 3);
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}
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ok = ReadHuffmanCodeLengths(dec, code_length_code_lengths, alphabet_size,
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code_lengths);
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if (ok) {
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ok = HuffmanTreeBuildImplicit(tree, code_lengths, alphabet_size);
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}
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free(code_lengths);
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}
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ok = ok && !br->error_;
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if (!ok) {
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dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
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return 0;
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}
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return 1;
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}
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static void DeleteHtreeGroups(HTreeGroup* htree_groups, int num_htree_groups) {
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if (htree_groups != NULL) {
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int i, j;
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for (i = 0; i < num_htree_groups; ++i) {
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HuffmanTree* const htrees = htree_groups[i].htrees_;
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for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
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HuffmanTreeRelease(&htrees[j]);
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}
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}
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free(htree_groups);
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}
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}
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static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
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int color_cache_bits, int allow_recursion) {
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int i, j;
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VP8LBitReader* const br = &dec->br_;
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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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int num_htree_groups = 1;
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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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const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision);
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const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision);
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const int huffman_pixs = huffman_xsize * huffman_ysize;
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if (!DecodeImageStream(huffman_xsize, huffman_ysize, 0, dec,
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&huffman_image)) {
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dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
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goto Error;
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}
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hdr->huffman_subsample_bits_ = huffman_precision;
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for (i = 0; i < huffman_pixs; ++i) {
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// The huffman data is stored in red and green bytes.
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const int group = (huffman_image[i] >> 8) & 0xffff;
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huffman_image[i] = group;
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if (group >= num_htree_groups) {
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num_htree_groups = group + 1;
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}
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}
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}
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if (br->error_) goto Error;
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assert(num_htree_groups <= 0x10000);
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htree_groups =
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(HTreeGroup*)WebPSafeCalloc((uint64_t)num_htree_groups,
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sizeof(*htree_groups));
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if (htree_groups == NULL) {
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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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for (i = 0; i < num_htree_groups; ++i) {
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HuffmanTree* const htrees = htree_groups[i].htrees_;
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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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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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if (!ReadHuffmanCode(alphabet_size, dec, htrees + j)) goto Error;
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}
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}
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// All OK. Finalize pointers and return.
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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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return 1;
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Error:
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free(huffman_image);
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DeleteHtreeGroups(htree_groups, num_htree_groups);
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return 0;
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}
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//------------------------------------------------------------------------------
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// Scaling.
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static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) {
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const int num_channels = 4;
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const int in_width = io->mb_w;
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const int out_width = io->scaled_width;
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const int in_height = io->mb_h;
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const int out_height = io->scaled_height;
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const uint64_t work_size = 2 * num_channels * (uint64_t)out_width;
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int32_t* work; // Rescaler work area.
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const uint64_t scaled_data_size = num_channels * (uint64_t)out_width;
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uint32_t* scaled_data; // Temporary storage for scaled BGRA data.
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const uint64_t memory_size = sizeof(*dec->rescaler) +
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work_size * sizeof(*work) +
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scaled_data_size * sizeof(*scaled_data);
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uint8_t* memory = (uint8_t*)WebPSafeCalloc(memory_size, sizeof(*memory));
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if (memory == NULL) {
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dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
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return 0;
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}
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assert(dec->rescaler_memory == NULL);
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dec->rescaler_memory = memory;
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dec->rescaler = (WebPRescaler*)memory;
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memory += sizeof(*dec->rescaler);
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work = (int32_t*)memory;
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memory += work_size * sizeof(*work);
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scaled_data = (uint32_t*)memory;
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WebPRescalerInit(dec->rescaler, in_width, in_height, (uint8_t*)scaled_data,
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out_width, out_height, 0, num_channels,
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in_width, out_width, in_height, out_height, work);
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return 1;
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}
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//------------------------------------------------------------------------------
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// Export to ARGB
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// We have special "export" function since we need to convert from BGRA
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static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace,
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int rgba_stride, uint8_t* const rgba) {
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const uint32_t* const src = (const uint32_t*)rescaler->dst;
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const int dst_width = rescaler->dst_width;
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int num_lines_out = 0;
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while (WebPRescalerHasPendingOutput(rescaler)) {
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uint8_t* const dst = rgba + num_lines_out * rgba_stride;
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WebPRescalerExportRow(rescaler);
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VP8LConvertFromBGRA(src, dst_width, colorspace, dst);
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++num_lines_out;
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}
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return num_lines_out;
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}
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// Emit scaled rows.
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static int EmitRescaledRows(const VP8LDecoder* const dec,
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const uint32_t* const data, int in_stride, int mb_h,
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uint8_t* const out, int out_stride) {
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const WEBP_CSP_MODE colorspace = dec->output_->colorspace;
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const uint8_t* const in = (const uint8_t*)data;
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int num_lines_in = 0;
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int num_lines_out = 0;
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while (num_lines_in < mb_h) {
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const uint8_t* const row_in = in + num_lines_in * in_stride;
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uint8_t* const row_out = out + num_lines_out * out_stride;
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num_lines_in += WebPRescalerImport(dec->rescaler, mb_h - num_lines_in,
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row_in, in_stride);
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num_lines_out += Export(dec->rescaler, colorspace, out_stride, row_out);
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}
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return num_lines_out;
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|
}
|
|
|
|
// Emit rows without any scaling.
|
|
static int EmitRows(WEBP_CSP_MODE colorspace,
|
|
const uint32_t* const data, int in_stride,
|
|
int mb_w, int mb_h,
|
|
uint8_t* const out, int out_stride) {
|
|
int lines = mb_h;
|
|
const uint8_t* row_in = (const uint8_t*)data;
|
|
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
|
|
{
|
|
int i;
|
|
uint8_t* const y = buf->y + y_pos * buf->y_stride;
|
|
for (i = 0; i < width; ++i) {
|
|
const uint32_t p = src[i];
|
|
y[i] = VP8RGBToY((p >> 16) & 0xff, (p >> 8) & 0xff, (p >> 0) & 0xff);
|
|
}
|
|
}
|
|
|
|
// 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;
|
|
const int uv_width = width >> 1;
|
|
int i;
|
|
for (i = 0; i < uv_width; ++i) {
|
|
const uint32_t v0 = src[2 * i + 0];
|
|
const uint32_t v1 = src[2 * i + 1];
|
|
// VP8RGBToU/V expects four accumulated pixels. Hence we need to
|
|
// scale r/g/b value by a factor 2. We just shift v0/v1 one bit less.
|
|
const int r = ((v0 >> 15) & 0x1fe) + ((v1 >> 15) & 0x1fe);
|
|
const int g = ((v0 >> 7) & 0x1fe) + ((v1 >> 7) & 0x1fe);
|
|
const int b = ((v0 << 1) & 0x1fe) + ((v1 << 1) & 0x1fe);
|
|
if (!(y_pos & 1)) { // even lines: store values
|
|
u[i] = VP8RGBToU(r, g, b);
|
|
v[i] = VP8RGBToV(r, g, b);
|
|
} else { // odd lines: average with previous values
|
|
const int tmp_u = VP8RGBToU(r, g, b);
|
|
const int tmp_v = VP8RGBToV(r, g, b);
|
|
// Approximated average-of-four. But it's an acceptable diff.
|
|
u[i] = (u[i] + tmp_u + 1) >> 1;
|
|
v[i] = (v[i] + tmp_v + 1) >> 1;
|
|
}
|
|
}
|
|
if (width & 1) { // last pixel
|
|
const uint32_t v0 = src[2 * i + 0];
|
|
const int r = (v0 >> 14) & 0x3fc;
|
|
const int g = (v0 >> 6) & 0x3fc;
|
|
const int b = (v0 << 2) & 0x3fc;
|
|
if (!(y_pos & 1)) { // even lines
|
|
u[i] = VP8RGBToU(r, g, b);
|
|
v[i] = VP8RGBToV(r, g, b);
|
|
} else { // odd lines (note: we could just skip this)
|
|
const int tmp_u = VP8RGBToU(r, g, b);
|
|
const int tmp_v = VP8RGBToV(r, g, b);
|
|
u[i] = (u[i] + tmp_u + 1) >> 1;
|
|
v[i] = (v[i] + tmp_v + 1) >> 1;
|
|
}
|
|
}
|
|
}
|
|
// Lastly, store alpha if needed.
|
|
if (buf->a != NULL) {
|
|
int i;
|
|
uint8_t* const a = buf->a + y_pos * buf->a_stride;
|
|
for (i = 0; i < width; ++i) a[i] = (src[i] >> 24);
|
|
}
|
|
}
|
|
|
|
static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) {
|
|
WebPRescaler* const rescaler = dec->rescaler;
|
|
const uint32_t* const src = (const uint32_t*)rescaler->dst;
|
|
const int dst_width = rescaler->dst_width;
|
|
int num_lines_out = 0;
|
|
while (WebPRescalerHasPendingOutput(rescaler)) {
|
|
WebPRescalerExportRow(rescaler);
|
|
ConvertToYUVA(src, dst_width, y_pos, dec->output_);
|
|
++y_pos;
|
|
++num_lines_out;
|
|
}
|
|
return num_lines_out;
|
|
}
|
|
|
|
static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec,
|
|
const uint32_t* const data,
|
|
int in_stride, int mb_h) {
|
|
const uint8_t* const in = (const uint8_t*)data;
|
|
int num_lines_in = 0;
|
|
int y_pos = dec->last_out_row_;
|
|
while (num_lines_in < mb_h) {
|
|
const uint8_t* const row_in = in + num_lines_in * in_stride;
|
|
num_lines_in += WebPRescalerImport(dec->rescaler, mb_h - num_lines_in,
|
|
row_in, in_stride);
|
|
y_pos += ExportYUVA(dec, y_pos);
|
|
}
|
|
return y_pos;
|
|
}
|
|
|
|
static int EmitRowsYUVA(const VP8LDecoder* const dec,
|
|
const uint32_t* const data, int in_stride,
|
|
int mb_w, int num_rows) {
|
|
int y_pos = dec->last_out_row_;
|
|
const uint8_t* row_in = (const uint8_t*)data;
|
|
while (num_rows-- > 0) {
|
|
ConvertToYUVA((const uint32_t*)row_in, mb_w, y_pos, dec->output_);
|
|
row_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 'pixel_stride' is in units of 'uint32_t' (and not 'bytes).
|
|
// Returns true if the crop window is not empty.
|
|
static int SetCropWindow(VP8Io* const io, int y_start, int y_end,
|
|
const uint32_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 += pixel_stride * delta;
|
|
}
|
|
if (y_start >= y_end) return 0; // Crop window is empty.
|
|
|
|
*in_data += io->crop_left;
|
|
|
|
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 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_;
|
|
|
|
// Inverse transforms.
|
|
// TODO: most transforms only need to operate on the cropped region only.
|
|
memcpy(rows_out, rows_in, cache_pixs * sizeof(*rows_out));
|
|
while (n-- > 0) {
|
|
VP8LTransform* const transform = &dec->transforms_[n];
|
|
VP8LInverseTransform(transform, start_row, end_row, rows_in, rows_out);
|
|
rows_in = rows_out;
|
|
}
|
|
}
|
|
|
|
// Special method for paletted alpha data.
|
|
static void ApplyInverseTransformsAlpha(VP8LDecoder* const dec, int num_rows,
|
|
const uint8_t* const rows) {
|
|
const int start_row = dec->last_row_;
|
|
const int end_row = start_row + num_rows;
|
|
const uint8_t* rows_in = rows;
|
|
uint8_t* rows_out = (uint8_t*)dec->io_->opaque + dec->io_->width * start_row;
|
|
VP8LTransform* const transform = &dec->transforms_[0];
|
|
assert(dec->next_transform_ == 1);
|
|
assert(transform->type_ == COLOR_INDEXING_TRANSFORM);
|
|
VP8LColorIndexInverseTransformAlpha(transform, start_row, end_row, rows_in,
|
|
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_;
|
|
|
|
if (num_rows <= 0) return; // Nothing to be done.
|
|
ApplyInverseTransforms(dec, num_rows, rows);
|
|
|
|
// Emit output.
|
|
{
|
|
VP8Io* const io = dec->io_;
|
|
const uint32_t* rows_data = dec->argb_cache_;
|
|
if (!SetCropWindow(io, dec->last_row_, row, &rows_data, io->width)) {
|
|
// Nothing to output (this time).
|
|
} else {
|
|
const WebPDecBuffer* const output = dec->output_;
|
|
const int in_stride = io->width * sizeof(*rows_data);
|
|
if (output->colorspace < MODE_YUV) { // convert to RGBA
|
|
const WebPRGBABuffer* const buf = &output->u.RGBA;
|
|
uint8_t* const rgba = buf->rgba + dec->last_out_row_ * buf->stride;
|
|
const int num_rows_out = io->use_scaling ?
|
|
EmitRescaledRows(dec, rows_data, in_stride, io->mb_h,
|
|
rgba, buf->stride) :
|
|
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_);
|
|
}
|
|
|
|
#define DECODE_DATA_FUNC(FUNC_NAME, TYPE, STORE_PIXEL) \
|
|
static int FUNC_NAME(VP8LDecoder* const dec, TYPE* const data, int width, \
|
|
int height, ProcessRowsFunc process_func) { \
|
|
int ok = 1; \
|
|
int col = 0, row = 0; \
|
|
VP8LBitReader* const br = &dec->br_; \
|
|
VP8LMetadata* const hdr = &dec->hdr_; \
|
|
HTreeGroup* htree_group = hdr->htree_groups_; \
|
|
TYPE* src = data; \
|
|
TYPE* last_cached = data; \
|
|
TYPE* const src_end = data + width * height; \
|
|
const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES; \
|
|
const int color_cache_limit = len_code_limit + hdr->color_cache_size_; \
|
|
VP8LColorCache* const color_cache = \
|
|
(hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL; \
|
|
const int mask = hdr->huffman_mask_; \
|
|
assert(htree_group != NULL); \
|
|
while (!br->eos_ && src < src_end) { \
|
|
int code; \
|
|
/* 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); \
|
|
} \
|
|
VP8LFillBitWindow(br); \
|
|
code = ReadSymbol(&htree_group->htrees_[GREEN], br); \
|
|
if (code < NUM_LITERAL_CODES) { /* Literal*/ \
|
|
int red, green, blue, alpha; \
|
|
red = ReadSymbol(&htree_group->htrees_[RED], br); \
|
|
green = code; \
|
|
VP8LFillBitWindow(br); \
|
|
blue = ReadSymbol(&htree_group->htrees_[BLUE], br); \
|
|
alpha = ReadSymbol(&htree_group->htrees_[ALPHA], br); \
|
|
*src = STORE_PIXEL(alpha, red, green, blue); \
|
|
AdvanceByOne: \
|
|
++src; \
|
|
++col; \
|
|
if (col >= width) { \
|
|
col = 0; \
|
|
++row; \
|
|
if ((process_func != NULL) && (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 (src - data < dist || src_end - src < length) { \
|
|
ok = 0; \
|
|
goto End; \
|
|
} \
|
|
{ \
|
|
int i; \
|
|
for (i = 0; i < length; ++i) src[i] = src[i - dist]; \
|
|
src += length; \
|
|
} \
|
|
col += length; \
|
|
while (col >= width) { \
|
|
col -= width; \
|
|
++row; \
|
|
if ((process_func != NULL) && (row % NUM_ARGB_CACHE_ROWS == 0)) { \
|
|
process_func(dec, row); \
|
|
} \
|
|
} \
|
|
if (src < src_end) { \
|
|
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 */ \
|
|
ok = 0; \
|
|
goto End; \
|
|
} \
|
|
ok = !br->error_; \
|
|
if (!ok) goto End; \
|
|
} \
|
|
/* Process the remaining rows corresponding to last row-block. */ \
|
|
if (process_func != NULL) process_func(dec, row); \
|
|
End: \
|
|
if (br->error_ || !ok || (br->eos_ && src < src_end)) { \
|
|
ok = 0; \
|
|
dec->status_ = \
|
|
(!br->eos_) ? VP8_STATUS_BITSTREAM_ERROR : VP8_STATUS_SUSPENDED; \
|
|
} else if (src == src_end) { \
|
|
dec->state_ = READ_DATA; \
|
|
} \
|
|
return ok; \
|
|
}
|
|
|
|
static WEBP_INLINE uint32_t GetARGBPixel(int alpha, int red, int green,
|
|
int blue) {
|
|
return (alpha << 24) | (red << 16) | (green << 8) | blue;
|
|
}
|
|
|
|
static WEBP_INLINE uint8_t GetAlphaPixel(int alpha, int red, int green,
|
|
int blue) {
|
|
(void)alpha;
|
|
(void)red;
|
|
(void)blue;
|
|
return green; // Alpha value is stored in green channel.
|
|
}
|
|
|
|
DECODE_DATA_FUNC(DecodeImageData, uint32_t, GetARGBPixel)
|
|
DECODE_DATA_FUNC(DecodeAlphaData, uint8_t, GetAlphaPixel)
|
|
|
|
#undef DECODE_DATA_FUNC
|
|
|
|
// -----------------------------------------------------------------------------
|
|
// VP8LTransform
|
|
|
|
static void ClearTransform(VP8LTransform* const transform) {
|
|
free(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 AddPixelEq(), 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.
|
|
free(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:
|
|
break;
|
|
default:
|
|
assert(0); // can't happen
|
|
break;
|
|
}
|
|
|
|
return ok;
|
|
}
|
|
|
|
// -----------------------------------------------------------------------------
|
|
// VP8LMetadata
|
|
|
|
static void InitMetadata(VP8LMetadata* const hdr) {
|
|
assert(hdr);
|
|
memset(hdr, 0, sizeof(*hdr));
|
|
}
|
|
|
|
static void ClearMetadata(VP8LMetadata* const hdr) {
|
|
assert(hdr);
|
|
|
|
free(hdr->huffman_image_);
|
|
DeleteHtreeGroups(hdr->htree_groups_, hdr->num_htree_groups_);
|
|
VP8LColorCacheClear(&hdr->color_cache_);
|
|
InitMetadata(hdr);
|
|
}
|
|
|
|
// -----------------------------------------------------------------------------
|
|
// VP8LDecoder
|
|
|
|
VP8LDecoder* VP8LNew(void) {
|
|
VP8LDecoder* const dec = (VP8LDecoder*)calloc(1, sizeof(*dec));
|
|
if (dec == NULL) return NULL;
|
|
dec->status_ = VP8_STATUS_OK;
|
|
dec->action_ = READ_DIM;
|
|
dec->state_ = READ_DIM;
|
|
return dec;
|
|
}
|
|
|
|
void VP8LClear(VP8LDecoder* const dec) {
|
|
int i;
|
|
if (dec == NULL) return;
|
|
ClearMetadata(&dec->hdr_);
|
|
|
|
free(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;
|
|
|
|
free(dec->rescaler_memory);
|
|
dec->rescaler_memory = NULL;
|
|
|
|
dec->output_ = NULL; // leave no trace behind
|
|
}
|
|
|
|
void VP8LDelete(VP8LDecoder* const dec) {
|
|
if (dec != NULL) {
|
|
VP8LClear(dec);
|
|
free(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, NULL);
|
|
ok = ok && !br->error_;
|
|
|
|
End:
|
|
|
|
if (!ok) {
|
|
free(data);
|
|
ClearMetadata(hdr);
|
|
// If not enough data (br.eos_) resulted in BIT_STREAM_ERROR, update the
|
|
// status appropriately.
|
|
if (dec->status_ == VP8_STATUS_BITSTREAM_ERROR && dec->br_.eos_) {
|
|
dec->status_ = VP8_STATUS_SUSPENDED;
|
|
}
|
|
} 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);
|
|
}
|
|
if (!is_level0) ClearMetadata(hdr); // Clean up temporary data behind.
|
|
}
|
|
return ok;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Allocate internal buffers dec->pixels_ and dec->argb_cache_.
|
|
static int AllocateInternalBuffers(VP8LDecoder* const dec, int final_width,
|
|
size_t bytes_per_pixel) {
|
|
const int argb_cache_needed = (bytes_per_pixel == sizeof(uint32_t));
|
|
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 =
|
|
argb_cache_needed ? (uint16_t)final_width : 0ULL;
|
|
// Scratch buffer for temporary BGRA storage. Not needed for paletted alpha.
|
|
const uint64_t cache_pixels =
|
|
argb_cache_needed ? (uint64_t)final_width * NUM_ARGB_CACHE_ROWS : 0ULL;
|
|
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, bytes_per_pixel);
|
|
if (dec->pixels_ == NULL) {
|
|
dec->argb_cache_ = NULL; // for sanity check
|
|
dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
|
|
return 0;
|
|
}
|
|
dec->argb_cache_ =
|
|
argb_cache_needed ? dec->pixels_ + num_pixels + cache_top_pixels : NULL;
|
|
return 1;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
|
|
// Special row-processing that only stores the alpha data.
|
|
static void ExtractAlphaRows(VP8LDecoder* const dec, int row) {
|
|
const int num_rows = row - dec->last_row_;
|
|
const uint32_t* const in = dec->pixels_ + dec->width_ * dec->last_row_;
|
|
|
|
if (num_rows <= 0) return; // Nothing to be done.
|
|
ApplyInverseTransforms(dec, num_rows, in);
|
|
|
|
// Extract alpha (which is stored in the green plane).
|
|
{
|
|
const int width = dec->io_->width; // the final width (!= dec->width_)
|
|
const int cache_pixs = width * num_rows;
|
|
uint8_t* const dst = (uint8_t*)dec->io_->opaque + width * dec->last_row_;
|
|
const uint32_t* const src = dec->argb_cache_;
|
|
int i;
|
|
for (i = 0; i < cache_pixs; ++i) dst[i] = (src[i] >> 8) & 0xff;
|
|
}
|
|
dec->last_row_ = dec->last_out_row_ = row;
|
|
}
|
|
|
|
// Row-processing for the special case when alpha data contains only one
|
|
// transform: color indexing.
|
|
static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int row) {
|
|
const int num_rows = row - dec->last_row_;
|
|
const uint8_t* const in =
|
|
(uint8_t*)dec->pixels_ + dec->width_ * dec->last_row_;
|
|
if (num_rows <= 0) return; // Nothing to be done.
|
|
ApplyInverseTransformsAlpha(dec, num_rows, in);
|
|
dec->last_row_ = dec->last_out_row_ = row;
|
|
}
|
|
|
|
int VP8LDecodeAlphaImageStream(int width, int height, const uint8_t* const data,
|
|
size_t data_size, uint8_t* const output) {
|
|
VP8Io io;
|
|
int ok = 0;
|
|
VP8LDecoder* const dec = VP8LNew();
|
|
size_t bytes_per_pixel = sizeof(uint32_t); // Default: BGRA mode.
|
|
if (dec == NULL) return 0;
|
|
|
|
dec->width_ = width;
|
|
dec->height_ = height;
|
|
dec->io_ = &io;
|
|
|
|
VP8InitIo(&io);
|
|
WebPInitCustomIo(NULL, &io); // Just a sanity Init. io won't be used.
|
|
io.opaque = output;
|
|
io.width = width;
|
|
io.height = height;
|
|
|
|
dec->status_ = VP8_STATUS_OK;
|
|
VP8LInitBitReader(&dec->br_, data, data_size);
|
|
|
|
dec->action_ = READ_HDR;
|
|
if (!DecodeImageStream(width, 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 &&
|
|
dec->hdr_.color_cache_size_ == 0) {
|
|
bytes_per_pixel = sizeof(uint8_t);
|
|
}
|
|
|
|
// Allocate internal buffers (note that dec->width_ may have changed here).
|
|
if (!AllocateInternalBuffers(dec, width, bytes_per_pixel)) goto Err;
|
|
|
|
// Decode (with special row processing).
|
|
dec->action_ = READ_DATA;
|
|
ok = (bytes_per_pixel == sizeof(uint8_t)) ?
|
|
DecodeAlphaData(dec, (uint8_t*)dec->pixels_, dec->width_, dec->height_,
|
|
ExtractPalettedAlphaRows) :
|
|
DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
|
|
ExtractAlphaRows);
|
|
|
|
Err:
|
|
VP8LDelete(dec);
|
|
return ok;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
|
|
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;
|
|
|
|
dec->action_ = READ_HDR;
|
|
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) {
|
|
const size_t bytes_per_pixel = sizeof(uint32_t);
|
|
VP8Io* io = NULL;
|
|
WebPDecParams* params = NULL;
|
|
|
|
// Sanity checks.
|
|
if (dec == NULL) return 0;
|
|
|
|
io = dec->io_;
|
|
assert(io != NULL);
|
|
params = (WebPDecParams*)io->opaque;
|
|
assert(params != NULL);
|
|
dec->output_ = params->output;
|
|
assert(dec->output_ != NULL);
|
|
|
|
// Initialization.
|
|
if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) {
|
|
dec->status_ = VP8_STATUS_INVALID_PARAM;
|
|
goto Err;
|
|
}
|
|
|
|
if (!AllocateInternalBuffers(dec, io->width, bytes_per_pixel)) goto Err;
|
|
|
|
if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err;
|
|
|
|
// Decode.
|
|
dec->action_ = READ_DATA;
|
|
if (!DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
|
|
ProcessRows)) {
|
|
goto Err;
|
|
}
|
|
|
|
// Cleanup.
|
|
params->last_y = dec->last_out_row_;
|
|
VP8LClear(dec);
|
|
return 1;
|
|
|
|
Err:
|
|
VP8LClear(dec);
|
|
assert(dec->status_ != VP8_STATUS_OK);
|
|
return 0;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
|
|
#if defined(__cplusplus) || defined(c_plusplus)
|
|
} // extern "C"
|
|
#endif
|