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// Copyright 2011 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.
// -----------------------------------------------------------------------------
//
// Incremental decoding
//
// Author: somnath@google.com (Somnath Banerjee)
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "src/dec/alphai_dec.h"
#include "src/dec/vp8_dec.h"
#include "src/dec/vp8i_dec.h"
#include "src/dec/vp8li_dec.h"
#include "src/dec/webpi_dec.h"
#include "src/utils/bit_reader_utils.h"
#include "src/utils/thread_utils.h"
#include "src/utils/utils.h"
#include "src/webp/decode.h"
#include "src/webp/format_constants.h"
#include "src/webp/types.h"
// In append mode, buffer allocations increase as multiples of this value.
// Needs to be a power of 2.
#define CHUNK_SIZE 4096
#define MAX_MB_SIZE 4096
//------------------------------------------------------------------------------
// Data structures for memory and states
// Decoding states. State normally flows as:
// WEBP_HEADER->VP8_HEADER->VP8_PARTS0->VP8_DATA->DONE for a lossy image, and
// WEBP_HEADER->VP8L_HEADER->VP8L_DATA->DONE for a lossless image.
// If there is any error the decoder goes into state ERROR.
typedef enum {
STATE_WEBP_HEADER, // All the data before that of the VP8/VP8L chunk.
STATE_VP8_HEADER, // The VP8 Frame header (within the VP8 chunk).
STATE_VP8_PARTS0,
STATE_VP8_DATA,
STATE_VP8L_HEADER,
STATE_VP8L_DATA,
STATE_DONE,
STATE_ERROR
} DecState;
// Operating state for the MemBuffer
typedef enum {
MEM_MODE_NONE = 0,
MEM_MODE_APPEND,
MEM_MODE_MAP
} MemBufferMode;
// storage for partition #0 and partial data (in a rolling fashion)
typedef struct {
MemBufferMode mode; // Operation mode
size_t start; // start location of the data to be decoded
size_t end; // end location
size_t buf_size; // size of the allocated buffer
uint8_t* buf; // We don't own this buffer in case WebPIUpdate()
size_t part0_size; // size of partition #0
const uint8_t* part0_buf; // buffer to store partition #0
} MemBuffer;
struct WebPIDecoder {
DecState state; // current decoding state
WebPDecParams params; // Params to store output info
int is_lossless; // for down-casting 'dec'.
void* dec; // either a VP8Decoder or a VP8LDecoder instance
VP8Io io;
MemBuffer mem; // input memory buffer.
WebPDecBuffer output; // output buffer (when no external one is supplied,
// or if the external one has slow-memory)
WebPDecBuffer* final_output; // Slow-memory output to copy to eventually.
size_t chunk_size; // Compressed VP8/VP8L size extracted from Header.
int last_mb_y; // last row reached for intra-mode decoding
};
// MB context to restore in case VP8DecodeMB() fails
typedef struct {
VP8MB left;
VP8MB info;
VP8BitReader token_br;
} MBContext;
//------------------------------------------------------------------------------
// MemBuffer: incoming data handling
static WEBP_INLINE size_t MemDataSize(const MemBuffer* mem) {
return (mem->end - mem->start);
}
// Check if we need to preserve the compressed alpha data, as it may not have
// been decoded yet.
static int NeedCompressedAlpha(const WebPIDecoder* const idec) {
if (idec->state == STATE_WEBP_HEADER) {
// We haven't parsed the headers yet, so we don't know whether the image is
// lossy or lossless. This also means that we haven't parsed the ALPH chunk.
return 0;
}
if (idec->is_lossless) {
return 0; // ALPH chunk is not present for lossless images.
} else {
const VP8Decoder* const dec = (VP8Decoder*)idec->dec;
assert(dec != NULL); // Must be true as idec->state != STATE_WEBP_HEADER.
return (dec->alpha_data != NULL) && !dec->is_alpha_decoded;
}
}
static void DoRemap(WebPIDecoder* const idec, ptrdiff_t offset) {
MemBuffer* const mem = &idec->mem;
const uint8_t* const new_base = mem->buf + mem->start;
// note: for VP8, setting up idec->io is only really needed at the beginning
// of the decoding, till partition #0 is complete.
idec->io.data = new_base;
idec->io.data_size = MemDataSize(mem);
if (idec->dec != NULL) {
if (!idec->is_lossless) {
VP8Decoder* const dec = (VP8Decoder*)idec->dec;
const uint32_t last_part = dec->num_parts_minus_one;
if (offset != 0) {
uint32_t p;
for (p = 0; p <= last_part; ++p) {
VP8RemapBitReader(dec->parts + p, offset);
}
// Remap partition #0 data pointer to new offset, but only in MAP
// mode (in APPEND mode, partition #0 is copied into a fixed memory).
if (mem->mode == MEM_MODE_MAP) {
VP8RemapBitReader(&dec->br, offset);
}
}
{
const uint8_t* const last_start = dec->parts[last_part].buf;
// 'last_start' will be NULL when 'idec->state' is < STATE_VP8_PARTS0
// and through a portion of that state (when there isn't enough data to
// parse the partitions). The bitreader is only used meaningfully when
// there is enough data to begin parsing partition 0.
if (last_start != NULL) {
VP8BitReaderSetBuffer(&dec->parts[last_part], last_start,
mem->buf + mem->end - last_start);
}
}
if (NeedCompressedAlpha(idec)) {
ALPHDecoder* const alph_dec = dec->alph_dec;
dec->alpha_data += offset;
if (alph_dec != NULL && alph_dec->vp8l_dec != NULL) {
if (alph_dec->method == ALPHA_LOSSLESS_COMPRESSION) {
VP8LDecoder* const alph_vp8l_dec = alph_dec->vp8l_dec;
assert(dec->alpha_data_size >= ALPHA_HEADER_LEN);
VP8LBitReaderSetBuffer(&alph_vp8l_dec->br,
dec->alpha_data + ALPHA_HEADER_LEN,
dec->alpha_data_size - ALPHA_HEADER_LEN);
} else { // alph_dec->method == ALPHA_NO_COMPRESSION
// Nothing special to do in this case.
}
}
}
} else { // Resize lossless bitreader
VP8LDecoder* const dec = (VP8LDecoder*)idec->dec;
VP8LBitReaderSetBuffer(&dec->br, new_base, MemDataSize(mem));
}
}
}
// Appends data to the end of MemBuffer->buf. It expands the allocated memory
// size if required and also updates VP8BitReader's if new memory is allocated.
WEBP_NODISCARD static int AppendToMemBuffer(WebPIDecoder* const idec,
const uint8_t* const data,
size_t data_size) {
VP8Decoder* const dec = (VP8Decoder*)idec->dec;
MemBuffer* const mem = &idec->mem;
const int need_compressed_alpha = NeedCompressedAlpha(idec);
const uint8_t* const old_start =
(mem->buf == NULL) ? NULL : mem->buf + mem->start;
const uint8_t* const old_base =
need_compressed_alpha ? dec->alpha_data : old_start;
assert(mem->buf != NULL || mem->start == 0);
assert(mem->mode == MEM_MODE_APPEND);
if (data_size > MAX_CHUNK_PAYLOAD) {
// security safeguard: trying to allocate more than what the format
// allows for a chunk should be considered a smoke smell.
return 0;
}
if (mem->end + data_size > mem->buf_size) { // Need some free memory
const size_t new_mem_start = old_start - old_base;
const size_t current_size = MemDataSize(mem) + new_mem_start;
const uint64_t new_size = (uint64_t)current_size + data_size;
const uint64_t extra_size = (new_size + CHUNK_SIZE - 1) & ~(CHUNK_SIZE - 1);
uint8_t* const new_buf =
(uint8_t*)WebPSafeMalloc(extra_size, sizeof(*new_buf));
if (new_buf == NULL) return 0;
if (old_base != NULL) memcpy(new_buf, old_base, current_size);
WebPSafeFree(mem->buf);
mem->buf = new_buf;
mem->buf_size = (size_t)extra_size;
mem->start = new_mem_start;
mem->end = current_size;
}
assert(mem->buf != NULL);
memcpy(mem->buf + mem->end, data, data_size);
mem->end += data_size;
assert(mem->end <= mem->buf_size);
DoRemap(idec, mem->buf + mem->start - old_start);
return 1;
}
WEBP_NODISCARD static int RemapMemBuffer(WebPIDecoder* const idec,
const uint8_t* const data,
size_t data_size) {
MemBuffer* const mem = &idec->mem;
const uint8_t* const old_buf = mem->buf;
const uint8_t* const old_start =
(old_buf == NULL) ? NULL : old_buf + mem->start;
assert(old_buf != NULL || mem->start == 0);
assert(mem->mode == MEM_MODE_MAP);
if (data_size < mem->buf_size) return 0; // can't remap to a shorter buffer!
mem->buf = (uint8_t*)data;
mem->end = mem->buf_size = data_size;
DoRemap(idec, mem->buf + mem->start - old_start);
return 1;
}
static void InitMemBuffer(MemBuffer* const mem) {
mem->mode = MEM_MODE_NONE;
mem->buf = NULL;
mem->buf_size = 0;
mem->part0_buf = NULL;
mem->part0_size = 0;
}
static void ClearMemBuffer(MemBuffer* const mem) {
assert(mem);
if (mem->mode == MEM_MODE_APPEND) {
WebPSafeFree(mem->buf);
WebPSafeFree((void*)mem->part0_buf);
}
}
WEBP_NODISCARD static int CheckMemBufferMode(MemBuffer* const mem,
MemBufferMode expected) {
if (mem->mode == MEM_MODE_NONE) {
mem->mode = expected; // switch to the expected mode
} else if (mem->mode != expected) {
return 0; // we mixed the modes => error
}
assert(mem->mode == expected); // mode is ok
return 1;
}
// To be called last.
WEBP_NODISCARD static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) {
const WebPDecoderOptions* const options = idec->params.options;
WebPDecBuffer* const output = idec->params.output;
idec->state = STATE_DONE;
if (options != NULL && options->flip) {
const VP8StatusCode status = WebPFlipBuffer(output);
if (status != VP8_STATUS_OK) return status;
}
if (idec->final_output != NULL) {
const VP8StatusCode status = WebPCopyDecBufferPixels(
output, idec->final_output); // do the slow-copy
WebPFreeDecBuffer(&idec->output);
if (status != VP8_STATUS_OK) return status;
*output = *idec->final_output;
idec->final_output = NULL;
}
return VP8_STATUS_OK;
}
//------------------------------------------------------------------------------
// Macroblock-decoding contexts
static void SaveContext(const VP8Decoder* dec, const VP8BitReader* token_br,
MBContext* const context) {
context->left = dec->mb_info[-1];
context->info = dec->mb_info[dec->mb_x];
context->token_br = *token_br;
}
static void RestoreContext(const MBContext* context, VP8Decoder* const dec,
VP8BitReader* const token_br) {
dec->mb_info[-1] = context->left;
dec->mb_info[dec->mb_x] = context->info;
*token_br = context->token_br;
}
//------------------------------------------------------------------------------
static VP8StatusCode IDecError(WebPIDecoder* const idec, VP8StatusCode error) {
if (idec->state == STATE_VP8_DATA) {
// Synchronize the thread, clean-up and check for errors.
(void)VP8ExitCritical((VP8Decoder*)idec->dec, &idec->io);
}
idec->state = STATE_ERROR;
return error;
}
static void ChangeState(WebPIDecoder* const idec, DecState new_state,
size_t consumed_bytes) {
MemBuffer* const mem = &idec->mem;
idec->state = new_state;
mem->start += consumed_bytes;
assert(mem->start <= mem->end);
idec->io.data = mem->buf + mem->start;
idec->io.data_size = MemDataSize(mem);
}
// Headers
static VP8StatusCode DecodeWebPHeaders(WebPIDecoder* const idec) {
MemBuffer* const mem = &idec->mem;
const uint8_t* data = mem->buf + mem->start;
size_t curr_size = MemDataSize(mem);
VP8StatusCode status;
WebPHeaderStructure headers;
headers.data = data;
headers.data_size = curr_size;
headers.have_all_data = 0;
status = WebPParseHeaders(&headers);
if (status == VP8_STATUS_NOT_ENOUGH_DATA) {
return VP8_STATUS_SUSPENDED; // We haven't found a VP8 chunk yet.
} else if (status != VP8_STATUS_OK) {
return IDecError(idec, status);
}
idec->chunk_size = headers.compressed_size;
idec->is_lossless = headers.is_lossless;
if (!idec->is_lossless) {
VP8Decoder* const dec = VP8New();
if (dec == NULL) {
return VP8_STATUS_OUT_OF_MEMORY;
}
dec->incremental = 1;
idec->dec = dec;
dec->alpha_data = headers.alpha_data;
dec->alpha_data_size = headers.alpha_data_size;
ChangeState(idec, STATE_VP8_HEADER, headers.offset);
} else {
VP8LDecoder* const dec = VP8LNew();
if (dec == NULL) {
return VP8_STATUS_OUT_OF_MEMORY;
}
idec->dec = dec;
ChangeState(idec, STATE_VP8L_HEADER, headers.offset);
}
return VP8_STATUS_OK;
}
static VP8StatusCode DecodeVP8FrameHeader(WebPIDecoder* const idec) {
const uint8_t* data = idec->mem.buf + idec->mem.start;
const size_t curr_size = MemDataSize(&idec->mem);
int width, height;
uint32_t bits;
if (curr_size < VP8_FRAME_HEADER_SIZE) {
// Not enough data bytes to extract VP8 Frame Header.
return VP8_STATUS_SUSPENDED;
}
if (!VP8GetInfo(data, curr_size, idec->chunk_size, &width, &height)) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
bits = data[0] | (data[1] << 8) | (data[2] << 16);
idec->mem.part0_size = (bits >> 5) + VP8_FRAME_HEADER_SIZE;
idec->io.data = data;
idec->io.data_size = curr_size;
idec->state = STATE_VP8_PARTS0;
return VP8_STATUS_OK;
}
// Partition #0
static VP8StatusCode CopyParts0Data(WebPIDecoder* const idec) {
VP8Decoder* const dec = (VP8Decoder*)idec->dec;
VP8BitReader* const br = &dec->br;
const size_t part_size = br->buf_end - br->buf;
MemBuffer* const mem = &idec->mem;
assert(!idec->is_lossless);
assert(mem->part0_buf == NULL);
// the following is a format limitation, no need for runtime check:
assert(part_size <= mem->part0_size);
if (part_size == 0) { // can't have zero-size partition #0
return VP8_STATUS_BITSTREAM_ERROR;
}
if (mem->mode == MEM_MODE_APPEND) {
// We copy and grab ownership of the partition #0 data.
uint8_t* const part0_buf = (uint8_t*)WebPSafeMalloc(1ULL, part_size);
if (part0_buf == NULL) {
return VP8_STATUS_OUT_OF_MEMORY;
}
memcpy(part0_buf, br->buf, part_size);
mem->part0_buf = part0_buf;
VP8BitReaderSetBuffer(br, part0_buf, part_size);
} else {
// Else: just keep pointers to the partition #0's data in dec->br.
}
mem->start += part_size;
return VP8_STATUS_OK;
}
static VP8StatusCode DecodePartition0(WebPIDecoder* const idec) {
VP8Decoder* const dec = (VP8Decoder*)idec->dec;
VP8Io* const io = &idec->io;
const WebPDecParams* const params = &idec->params;
WebPDecBuffer* const output = params->output;
// Wait till we have enough data for the whole partition #0
if (MemDataSize(&idec->mem) < idec->mem.part0_size) {
return VP8_STATUS_SUSPENDED;
}
if (!VP8GetHeaders(dec, io)) {
const VP8StatusCode status = dec->status;
if (status == VP8_STATUS_SUSPENDED ||
status == VP8_STATUS_NOT_ENOUGH_DATA) {
// treating NOT_ENOUGH_DATA as SUSPENDED state
return VP8_STATUS_SUSPENDED;
}
return IDecError(idec, status);
}
// Allocate/Verify output buffer now
dec->status = WebPAllocateDecBuffer(io->width, io->height, params->options,
output);
if (dec->status != VP8_STATUS_OK) {
return IDecError(idec, dec->status);
}
// This change must be done before calling VP8InitFrame()
dec->mt_method = VP8GetThreadMethod(params->options, NULL,
io->width, io->height);
VP8InitDithering(params->options, dec);
dec->status = CopyParts0Data(idec);
if (dec->status != VP8_STATUS_OK) {
return IDecError(idec, dec->status);
}
// Finish setting up the decoding parameters. Will call io->setup().
if (VP8EnterCritical(dec, io) != VP8_STATUS_OK) {
return IDecError(idec, dec->status);
}
// Note: past this point, teardown() must always be called
// in case of error.
idec->state = STATE_VP8_DATA;
// Allocate memory and prepare everything.
if (!VP8InitFrame(dec, io)) {
return IDecError(idec, dec->status);
}
return VP8_STATUS_OK;
}
// Remaining partitions
static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) {
VP8Decoder* const dec = (VP8Decoder*)idec->dec;
VP8Io* const io = &idec->io;
// Make sure partition #0 has been read before, to set dec to ready.
if (!dec->ready) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
for (; dec->mb_y < dec->mb_h; ++dec->mb_y) {
if (idec->last_mb_y != dec->mb_y) {
if (!VP8ParseIntraModeRow(&dec->br, dec)) {
// note: normally, error shouldn't occur since we already have the whole
// partition0 available here in DecodeRemaining(). Reaching EOF while
// reading intra modes really means a BITSTREAM_ERROR.
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
idec->last_mb_y = dec->mb_y;
}
for (; dec->mb_x < dec->mb_w; ++dec->mb_x) {
VP8BitReader* const token_br =
&dec->parts[dec->mb_y & dec->num_parts_minus_one];
MBContext context;
SaveContext(dec, token_br, &context);
if (!VP8DecodeMB(dec, token_br)) {
// We shouldn't fail when MAX_MB data was available
if (dec->num_parts_minus_one == 0 &&
MemDataSize(&idec->mem) > MAX_MB_SIZE) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
// Synchronize the threads.
if (dec->mt_method > 0) {
if (!WebPGetWorkerInterface()->Sync(&dec->worker)) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
}
RestoreContext(&context, dec, token_br);
return VP8_STATUS_SUSPENDED;
}
// Release buffer only if there is only one partition
if (dec->num_parts_minus_one == 0) {
idec->mem.start = token_br->buf - idec->mem.buf;
assert(idec->mem.start <= idec->mem.end);
}
}
VP8InitScanline(dec); // Prepare for next scanline
// Reconstruct, filter and emit the row.
if (!VP8ProcessRow(dec, io)) {
return IDecError(idec, VP8_STATUS_USER_ABORT);
}
}
// Synchronize the thread and check for errors.
if (!VP8ExitCritical(dec, io)) {
idec->state = STATE_ERROR; // prevent re-entry in IDecError
return IDecError(idec, VP8_STATUS_USER_ABORT);
}
dec->ready = 0;
return FinishDecoding(idec);
}
static VP8StatusCode ErrorStatusLossless(WebPIDecoder* const idec,
VP8StatusCode status) {
if (status == VP8_STATUS_SUSPENDED || status == VP8_STATUS_NOT_ENOUGH_DATA) {
return VP8_STATUS_SUSPENDED;
}
return IDecError(idec, status);
}
static VP8StatusCode DecodeVP8LHeader(WebPIDecoder* const idec) {
VP8Io* const io = &idec->io;
VP8LDecoder* const dec = (VP8LDecoder*)idec->dec;
const WebPDecParams* const params = &idec->params;
WebPDecBuffer* const output = params->output;
size_t curr_size = MemDataSize(&idec->mem);
assert(idec->is_lossless);
// Wait until there's enough data for decoding header.
if (curr_size < (idec->chunk_size >> 3)) {
dec->status = VP8_STATUS_SUSPENDED;
return ErrorStatusLossless(idec, dec->status);
}
if (!VP8LDecodeHeader(dec, io)) {
if (dec->status == VP8_STATUS_BITSTREAM_ERROR &&
curr_size < idec->chunk_size) {
dec->status = VP8_STATUS_SUSPENDED;
}
return ErrorStatusLossless(idec, dec->status);
}
// Allocate/verify output buffer now.
dec->status = WebPAllocateDecBuffer(io->width, io->height, params->options,
output);
if (dec->status != VP8_STATUS_OK) {
return IDecError(idec, dec->status);
}
idec->state = STATE_VP8L_DATA;
return VP8_STATUS_OK;
}
static VP8StatusCode DecodeVP8LData(WebPIDecoder* const idec) {
VP8LDecoder* const dec = (VP8LDecoder*)idec->dec;
const size_t curr_size = MemDataSize(&idec->mem);
assert(idec->is_lossless);
// Switch to incremental decoding if we don't have all the bytes available.
dec->incremental = (curr_size < idec->chunk_size);
if (!VP8LDecodeImage(dec)) {
return ErrorStatusLossless(idec, dec->status);
}
assert(dec->status == VP8_STATUS_OK || dec->status == VP8_STATUS_SUSPENDED);
return (dec->status == VP8_STATUS_SUSPENDED) ? dec->status
: FinishDecoding(idec);
}
// Main decoding loop
static VP8StatusCode IDecode(WebPIDecoder* idec) {
VP8StatusCode status = VP8_STATUS_SUSPENDED;
if (idec->state == STATE_WEBP_HEADER) {
status = DecodeWebPHeaders(idec);
} else {
if (idec->dec == NULL) {
return VP8_STATUS_SUSPENDED; // can't continue if we have no decoder.
}
}
if (idec->state == STATE_VP8_HEADER) {
status = DecodeVP8FrameHeader(idec);
}
if (idec->state == STATE_VP8_PARTS0) {
status = DecodePartition0(idec);
}
if (idec->state == STATE_VP8_DATA) {
const VP8Decoder* const dec = (VP8Decoder*)idec->dec;
if (dec == NULL) {
return VP8_STATUS_SUSPENDED; // can't continue if we have no decoder.
}
status = DecodeRemaining(idec);
}
if (idec->state == STATE_VP8L_HEADER) {
status = DecodeVP8LHeader(idec);
}
if (idec->state == STATE_VP8L_DATA) {
status = DecodeVP8LData(idec);
}
return status;
}
//------------------------------------------------------------------------------
// Internal constructor
WEBP_NODISCARD static WebPIDecoder* NewDecoder(
WebPDecBuffer* const output_buffer,
const WebPBitstreamFeatures* const features) {
WebPIDecoder* idec = (WebPIDecoder*)WebPSafeCalloc(1ULL, sizeof(*idec));
if (idec == NULL) {
return NULL;
}
idec->state = STATE_WEBP_HEADER;
idec->chunk_size = 0;
idec->last_mb_y = -1;
InitMemBuffer(&idec->mem);
if (!WebPInitDecBuffer(&idec->output) || !VP8InitIo(&idec->io)) {
WebPSafeFree(idec);
return NULL;
}
WebPResetDecParams(&idec->params);
if (output_buffer == NULL || WebPAvoidSlowMemory(output_buffer, features)) {
idec->params.output = &idec->output;
idec->final_output = output_buffer;
if (output_buffer != NULL) {
idec->params.output->colorspace = output_buffer->colorspace;
}
} else {
idec->params.output = output_buffer;
idec->final_output = NULL;
}
WebPInitCustomIo(&idec->params, &idec->io); // Plug the I/O functions.
return idec;
}
//------------------------------------------------------------------------------
// Public functions
WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) {
return NewDecoder(output_buffer, NULL);
}
WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size,
WebPDecoderConfig* config) {
WebPIDecoder* idec;
WebPBitstreamFeatures tmp_features;
WebPBitstreamFeatures* const features =
(config == NULL) ? &tmp_features : &config->input;
memset(&tmp_features, 0, sizeof(tmp_features));
// Parse the bitstream's features, if requested:
if (data != NULL && data_size > 0) {
if (WebPGetFeatures(data, data_size, features) != VP8_STATUS_OK) {
return NULL;
}
}
// Create an instance of the incremental decoder
idec = (config != NULL) ? NewDecoder(&config->output, features)
: NewDecoder(NULL, features);
if (idec == NULL) {
return NULL;
}
// Finish initialization
if (config != NULL) {
idec->params.options = &config->options;
}
return idec;
}
void WebPIDelete(WebPIDecoder* idec) {
if (idec == NULL) return;
if (idec->dec != NULL) {
if (!idec->is_lossless) {
if (idec->state == STATE_VP8_DATA) {
// Synchronize the thread, clean-up and check for errors.
// TODO(vrabaud) do we care about the return result?
(void)VP8ExitCritical((VP8Decoder*)idec->dec, &idec->io);
}
VP8Delete((VP8Decoder*)idec->dec);
} else {
VP8LDelete((VP8LDecoder*)idec->dec);
}
}
ClearMemBuffer(&idec->mem);
WebPFreeDecBuffer(&idec->output);
WebPSafeFree(idec);
}
//------------------------------------------------------------------------------
// Wrapper toward WebPINewDecoder
WebPIDecoder* WebPINewRGB(WEBP_CSP_MODE csp, uint8_t* output_buffer,
size_t output_buffer_size, int output_stride) {
const int is_external_memory = (output_buffer != NULL) ? 1 : 0;
WebPIDecoder* idec;
if (csp >= MODE_YUV) return NULL;
if (is_external_memory == 0) { // Overwrite parameters to sane values.
output_buffer_size = 0;
output_stride = 0;
} else { // A buffer was passed. Validate the other params.
if (output_stride == 0 || output_buffer_size == 0) {
return NULL; // invalid parameter.
}
}
idec = WebPINewDecoder(NULL);
if (idec == NULL) return NULL;
idec->output.colorspace = csp;
idec->output.is_external_memory = is_external_memory;
idec->output.u.RGBA.rgba = output_buffer;
idec->output.u.RGBA.stride = output_stride;
idec->output.u.RGBA.size = output_buffer_size;
return idec;
}
WebPIDecoder* WebPINewYUVA(uint8_t* luma, size_t luma_size, int luma_stride,
uint8_t* u, size_t u_size, int u_stride,
uint8_t* v, size_t v_size, int v_stride,
uint8_t* a, size_t a_size, int a_stride) {
const int is_external_memory = (luma != NULL) ? 1 : 0;
WebPIDecoder* idec;
WEBP_CSP_MODE colorspace;
if (is_external_memory == 0) { // Overwrite parameters to sane values.
luma_size = u_size = v_size = a_size = 0;
luma_stride = u_stride = v_stride = a_stride = 0;
u = v = a = NULL;
colorspace = MODE_YUVA;
} else { // A luma buffer was passed. Validate the other parameters.
if (u == NULL || v == NULL) return NULL;
if (luma_size == 0 || u_size == 0 || v_size == 0) return NULL;
if (luma_stride == 0 || u_stride == 0 || v_stride == 0) return NULL;
if (a != NULL) {
if (a_size == 0 || a_stride == 0) return NULL;
}
colorspace = (a == NULL) ? MODE_YUV : MODE_YUVA;
}
idec = WebPINewDecoder(NULL);
if (idec == NULL) return NULL;
idec->output.colorspace = colorspace;
idec->output.is_external_memory = is_external_memory;
idec->output.u.YUVA.y = luma;
idec->output.u.YUVA.y_stride = luma_stride;
idec->output.u.YUVA.y_size = luma_size;
idec->output.u.YUVA.u = u;
idec->output.u.YUVA.u_stride = u_stride;
idec->output.u.YUVA.u_size = u_size;
idec->output.u.YUVA.v = v;
idec->output.u.YUVA.v_stride = v_stride;
idec->output.u.YUVA.v_size = v_size;
idec->output.u.YUVA.a = a;
idec->output.u.YUVA.a_stride = a_stride;
idec->output.u.YUVA.a_size = a_size;
return idec;
}
WebPIDecoder* WebPINewYUV(uint8_t* luma, size_t luma_size, int luma_stride,
uint8_t* u, size_t u_size, int u_stride,
uint8_t* v, size_t v_size, int v_stride) {
return WebPINewYUVA(luma, luma_size, luma_stride,
u, u_size, u_stride,
v, v_size, v_stride,
NULL, 0, 0);
}
//------------------------------------------------------------------------------
static VP8StatusCode IDecCheckStatus(const WebPIDecoder* const idec) {
assert(idec);
if (idec->state == STATE_ERROR) {
return VP8_STATUS_BITSTREAM_ERROR;
}
if (idec->state == STATE_DONE) {
return VP8_STATUS_OK;
}
return VP8_STATUS_SUSPENDED;
}
VP8StatusCode WebPIAppend(WebPIDecoder* idec,
const uint8_t* data, size_t data_size) {
VP8StatusCode status;
if (idec == NULL || data == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
status = IDecCheckStatus(idec);
if (status != VP8_STATUS_SUSPENDED) {
return status;
}
// Check mixed calls between RemapMemBuffer and AppendToMemBuffer.
if (!CheckMemBufferMode(&idec->mem, MEM_MODE_APPEND)) {
return VP8_STATUS_INVALID_PARAM;
}
// Append data to memory buffer
if (!AppendToMemBuffer(idec, data, data_size)) {
return VP8_STATUS_OUT_OF_MEMORY;
}
return IDecode(idec);
}
VP8StatusCode WebPIUpdate(WebPIDecoder* idec,
const uint8_t* data, size_t data_size) {
VP8StatusCode status;
if (idec == NULL || data == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
status = IDecCheckStatus(idec);
if (status != VP8_STATUS_SUSPENDED) {
return status;
}
// Check mixed calls between RemapMemBuffer and AppendToMemBuffer.
if (!CheckMemBufferMode(&idec->mem, MEM_MODE_MAP)) {
return VP8_STATUS_INVALID_PARAM;
}
// Make the memory buffer point to the new buffer
if (!RemapMemBuffer(idec, data, data_size)) {
return VP8_STATUS_INVALID_PARAM;
}
return IDecode(idec);
}
//------------------------------------------------------------------------------
static const WebPDecBuffer* GetOutputBuffer(const WebPIDecoder* const idec) {
if (idec == NULL || idec->dec == NULL) {
return NULL;
}
if (idec->state <= STATE_VP8_PARTS0) {
return NULL;
}
if (idec->final_output != NULL) {
return NULL; // not yet slow-copied
}
return idec->params.output;
}
const WebPDecBuffer* WebPIDecodedArea(const WebPIDecoder* idec,
int* left, int* top,
int* width, int* height) {
const WebPDecBuffer* const src = GetOutputBuffer(idec);
if (left != NULL) *left = 0;
if (top != NULL) *top = 0;
if (src != NULL) {
if (width != NULL) *width = src->width;
if (height != NULL) *height = idec->params.last_y;
} else {
if (width != NULL) *width = 0;
if (height != NULL) *height = 0;
}
return src;
}
WEBP_NODISCARD uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int* last_y,
int* width, int* height, int* stride) {
const WebPDecBuffer* const src = GetOutputBuffer(idec);
if (src == NULL) return NULL;
if (src->colorspace >= MODE_YUV) {
return NULL;
}
if (last_y != NULL) *last_y = idec->params.last_y;
if (width != NULL) *width = src->width;
if (height != NULL) *height = src->height;
if (stride != NULL) *stride = src->u.RGBA.stride;
return src->u.RGBA.rgba;
}
WEBP_NODISCARD uint8_t* WebPIDecGetYUVA(const WebPIDecoder* idec, int* last_y,
uint8_t** u, uint8_t** v, uint8_t** a,
int* width, int* height, int* stride,
int* uv_stride, int* a_stride) {
const WebPDecBuffer* const src = GetOutputBuffer(idec);
if (src == NULL) return NULL;
if (src->colorspace < MODE_YUV) {
return NULL;
}
if (last_y != NULL) *last_y = idec->params.last_y;
if (u != NULL) *u = src->u.YUVA.u;
if (v != NULL) *v = src->u.YUVA.v;
if (a != NULL) *a = src->u.YUVA.a;
if (width != NULL) *width = src->width;
if (height != NULL) *height = src->height;
if (stride != NULL) *stride = src->u.YUVA.y_stride;
if (uv_stride != NULL) *uv_stride = src->u.YUVA.u_stride;
if (a_stride != NULL) *a_stride = src->u.YUVA.a_stride;
return src->u.YUVA.y;
}
int WebPISetIOHooks(WebPIDecoder* const idec,
VP8IoPutHook put,
VP8IoSetupHook setup,
VP8IoTeardownHook teardown,
void* user_data) {
if (idec == NULL || idec->state > STATE_WEBP_HEADER) {
return 0;
}
idec->io.put = put;
idec->io.setup = setup;
idec->io.teardown = teardown;
idec->io.opaque = user_data;
return 1;
}