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Extract some useful functions around decoding buffer WebPDecParams.

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This is to prepare for incremental decoding.

Change-Id: Ibb1ac6c1f2d10e096c4fbcf0c06bce77b30ca457
This commit is contained in:
Pascal Massimino 2011-03-08 19:23:16 -08:00
parent d5bc05a47b
commit 3e856e2dd6
3 changed files with 162 additions and 83 deletions
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2
src/dec/Makefile.am
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@ -6,7 +6,7 @@ libwebpdecode_la_LDFLAGS = -version-info 0:0:0
libwebpdecodeinclude_HEADERS = ../webp/decode.h ../webp/decode_vp8.h ../webp/types.h
libwebpdecodeincludedir = $(includedir)/webp
noinst_HEADERS = bits.h vp8i.h yuv.h
noinst_HEADERS = bits.h vp8i.h webpi.h yuv.h
noinst_LTLIBRARIES = libwebpdecode.la
# uncomment the following line (and comment the above) if you want

184
src/dec/webp.c
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@ -11,6 +11,7 @@
#include <stdlib.h>
#include "vp8i.h"
#include "webpi.h"
#include "yuv.h"
#if defined(__cplusplus) || defined(c_plusplus)
@ -37,8 +38,8 @@ static inline uint32_t get_le32(const uint8_t* const data) {
}
// If a RIFF container is detected, validate it and skip over it.
static uint32_t CheckRIFFHeader(const uint8_t** data_ptr,
uint32_t *data_size_ptr) {
uint32_t WebPCheckRIFFHeader(const uint8_t** data_ptr,
uint32_t *data_size_ptr) {
uint32_t chunk_size = 0xffffffffu;
if (*data_size_ptr >= 10 + 20 && !memcmp(*data_ptr, "RIFF", 4)) {
if (memcmp(*data_ptr + 8, "WEBP", 4)) {
@ -68,10 +69,6 @@ static uint32_t CheckRIFFHeader(const uint8_t** data_ptr,
//-----------------------------------------------------------------------------
// Fancy upscaling
typedef enum { MODE_RGB = 0, MODE_RGBA = 1,
MODE_BGR = 2, MODE_BGRA = 3,
MODE_YUV = 4 } CSP_MODE;
#ifdef FANCY_UPSCALING
// Given samples laid out in a square as:
@ -153,7 +150,7 @@ void UpscaleLinePair(const uint8_t* top_y, const uint8_t* bottom_y,
const uint8_t* top_u, const uint8_t* top_v,
const uint8_t* cur_u, const uint8_t* cur_v,
uint8_t* top_dst, uint8_t* bottom_dst, int len,
CSP_MODE mode) {
WEBP_CSP_MODE mode) {
if (mode == MODE_RGB) {
UpscaleRgbLinePair(top_y, bottom_y, top_u, top_v, cur_u, cur_v,
top_dst, bottom_dst, len);
@ -178,18 +175,8 @@ void UpscaleLinePair(const uint8_t* top_y, const uint8_t* bottom_y,
//-----------------------------------------------------------------------------
// Main conversion driver.
typedef struct {
uint8_t* output; // rgb(a) or luma
uint8_t *u, *v;
uint8_t *top_y, *top_u, *top_v;
int stride; // rgb(a) stride or luma stride
int u_stride;
int v_stride;
CSP_MODE mode;
} Params;
static int CustomPut(const VP8Io* io) {
Params *p = (Params*)io->opaque;
WebPDecParams *p = (WebPDecParams*)io->opaque;
const int w = io->width;
const int mb_h = io->mb_h;
const int uv_w = (w + 1) / 2;
@ -291,7 +278,7 @@ static int CustomPut(const VP8Io* io) {
static int CustomSetup(VP8Io* io) {
#ifdef FANCY_UPSCALING
Params *p = (Params*)io->opaque;
WebPDecParams *p = (WebPDecParams*)io->opaque;
p->top_y = p->top_u = p->top_v = NULL;
if (p->mode != MODE_YUV) {
const int uv_width = (io->width + 1) >> 1;
@ -309,7 +296,7 @@ static int CustomSetup(VP8Io* io) {
static void CustomTeardown(const VP8Io* io) {
#ifdef FANCY_UPSCALING
Params *p = (Params*)io->opaque;
WebPDecParams *p = (WebPDecParams*)io->opaque;
if (p->top_y) {
free(p->top_y);
p->top_y = p->top_u = p->top_v = NULL;
@ -317,12 +304,84 @@ static void CustomTeardown(const VP8Io* io) {
#endif
}
void WebPInitCustomIo(VP8Io* const io) {
io->put = CustomPut;
io->setup = CustomSetup;
io->teardown = CustomTeardown;
}
//-----------------------------------------------------------------------------
// Init/Check decoding parameters
int WebPInitDecParams(const uint8_t* data, uint32_t data_size, int* width,
int* height, WebPDecParams* const params) {
int w, h, stride;
int uv_size = 0;
int uv_stride = 0;
int size;
uint8_t* output;
WEBP_CSP_MODE mode = params->mode;
if (!WebPGetInfo(data, data_size, &w, &h)) {
return 0;
}
if (width) *width = w;
if (height) *height = h;
// initialize output buffer, now that dimensions are known.
stride = (mode == MODE_RGB || mode == MODE_BGR) ? 3 * w
: (mode == MODE_RGBA || mode == MODE_BGRA) ? 4 * w
: w;
size = stride * h;
if (mode == MODE_YUV) {
uv_stride = (w + 1) / 2;
uv_size = uv_stride * ((h + 1) / 2);
}
output = (uint8_t*)malloc(size + 2 * uv_size);
if (!output) {
return 0;
}
params->output = output;
params->stride = stride;
if (mode == MODE_YUV) {
params->u = output + size;
params->u_stride = uv_stride;
params->v = output + size + uv_size;
params->v_stride = uv_stride;
}
return 1;
}
int WebPCheckDecParams(const VP8Io* io, const WebPDecParams* params,
int output_size, int output_u_size, int output_v_size) {
int ok = 1;
WEBP_CSP_MODE mode = params->mode;
ok &= (params->stride * io->height <= output_size);
if (mode == MODE_RGB || mode == MODE_BGR) {
ok &= (params->stride >= io->width * 3);
} else if (mode == MODE_RGBA || mode == MODE_BGRA) {
ok &= (params->stride >= io->width * 4);
} else {
// some extra checks for U/V
const int u_size = params->u_stride * ((io->height + 1) / 2);
const int v_size = params->v_stride * ((io->height + 1) / 2);
ok &= (params->stride >= io->width);
ok &= (params->u_stride >= (io->width + 1) / 2) &&
(params->v_stride >= (io->width + 1) / 2);
ok &= (u_size <= output_u_size && v_size <= output_v_size);
}
return ok;
}
//-----------------------------------------------------------------------------
// "Into" variants
static uint8_t* DecodeInto(CSP_MODE mode,
static uint8_t* DecodeInto(WEBP_CSP_MODE mode,
const uint8_t* data, uint32_t data_size,
Params* params, int output_size,
WebPDecParams* params, int output_size,
int output_u_size, int output_v_size) {
VP8Decoder* dec = VP8New();
VP8Io io;
@ -338,30 +397,16 @@ static uint8_t* DecodeInto(CSP_MODE mode,
params->mode = mode;
io.opaque = params;
io.put = CustomPut;
io.setup = CustomSetup;
io.teardown = CustomTeardown;
WebPInitCustomIo(&io);
if (!VP8GetHeaders(dec, &io)) {
VP8Delete(dec);
return NULL;
}
// check output buffers
ok &= (params->stride * io.height <= output_size);
if (mode == MODE_RGB || mode == MODE_BGR) {
ok &= (params->stride >= io.width * 3);
} else if (mode == MODE_RGBA || mode == MODE_BGRA) {
ok &= (params->stride >= io.width * 4);
} else {
// some extra checks for U/V
const int u_size = params->u_stride * ((io.height + 1) / 2);
const int v_size = params->v_stride * ((io.height + 1) / 2);
ok &= (params->stride >= io.width);
ok &= (params->u_stride >= (io.width + 1) / 2) &&
(params->v_stride >= (io.width + 1) / 2);
ok &= (u_size <= output_u_size && v_size <= output_v_size);
}
// check output buffers
ok = WebPCheckDecParams(&io, params, output_size,
output_u_size, output_v_size);
if (!ok) {
VP8Delete(dec);
return NULL;
@ -379,7 +424,7 @@ static uint8_t* DecodeInto(CSP_MODE mode,
uint8_t* WebPDecodeRGBInto(const uint8_t* data, uint32_t data_size,
uint8_t* output, int output_size,
int output_stride) {
Params params;
WebPDecParams params;
if (output == NULL) {
return NULL;
@ -393,7 +438,7 @@ uint8_t* WebPDecodeRGBInto(const uint8_t* data, uint32_t data_size,
uint8_t* WebPDecodeRGBAInto(const uint8_t* data, uint32_t data_size,
uint8_t* output, int output_size,
int output_stride) {
Params params;
WebPDecParams params;
if (output == NULL) {
return NULL;
@ -407,7 +452,7 @@ uint8_t* WebPDecodeRGBAInto(const uint8_t* data, uint32_t data_size,
uint8_t* WebPDecodeBGRInto(const uint8_t* data, uint32_t data_size,
uint8_t* output, int output_size,
int output_stride) {
Params params;
WebPDecParams params;
if (output == NULL) {
return NULL;
@ -421,7 +466,7 @@ uint8_t* WebPDecodeBGRInto(const uint8_t* data, uint32_t data_size,
uint8_t* WebPDecodeBGRAInto(const uint8_t* data, uint32_t data_size,
uint8_t* output, int output_size,
int output_stride) {
Params params;
WebPDecParams params;
if (output == NULL) {
return NULL;
@ -436,7 +481,7 @@ uint8_t* WebPDecodeYUVInto(const uint8_t* data, uint32_t data_size,
uint8_t* luma, int luma_size, int luma_stride,
uint8_t* u, int u_size, int u_stride,
uint8_t* v, int v_size, int v_stride) {
Params params;
WebPDecParams params;
if (luma == NULL) {
return NULL;
@ -454,46 +499,21 @@ uint8_t* WebPDecodeYUVInto(const uint8_t* data, uint32_t data_size,
//-----------------------------------------------------------------------------
static uint8_t* Decode(CSP_MODE mode, const uint8_t* data, uint32_t data_size,
int* width, int* height, Params* params_out) {
int w, h, stride;
static uint8_t* Decode(WEBP_CSP_MODE mode, const uint8_t* data,
uint32_t data_size, int* width, int* height,
WebPDecParams* params_out) {
int size = 0;
int uv_size = 0;
int uv_stride = 0;
int size;
uint8_t* output;
Params params = { 0 };
WebPDecParams params = { 0 };
if (!WebPGetInfo(data, data_size, &w, &h)) {
params.mode = mode;
if (!WebPInitDecParams(data, data_size, width, height, &params)) {
return NULL;
}
if (width) *width = w;
if (height) *height = h;
// initialize output buffer, now that dimensions are known.
stride = (mode == MODE_RGB || mode == MODE_BGR) ? 3 * w
: (mode == MODE_RGBA || mode == MODE_BGRA) ? 4 * w
: w;
size = stride * h;
if (mode == MODE_YUV) {
uv_stride = (w + 1) / 2;
uv_size = uv_stride * ((h + 1) / 2);
}
output = (uint8_t*)malloc(size + 2 * uv_size);
if (!output) {
return NULL;
}
params.output = output;
params.stride = stride;
if (mode == MODE_YUV) {
params.u = output + size;
params.u_stride = uv_stride;
params.v = output + size + uv_size;
params.v_stride = uv_stride;
}
if (params_out) *params_out = params;
size = params.stride * (*height);
uv_size = params.u_stride * ((*height + 1) / 2);
return DecodeInto(mode, data, data_size, &params, size, uv_size, uv_size);
}
@ -520,7 +540,7 @@ uint8_t* WebPDecodeBGRA(const uint8_t* data, uint32_t data_size,
uint8_t* WebPDecodeYUV(const uint8_t* data, uint32_t data_size,
int *width, int *height, uint8_t** u, uint8_t** v,
int *stride, int* uv_stride) {
Params params;
WebPDecParams params;
uint8_t* const out = Decode(MODE_YUV, data, data_size,
width, height, &params);
@ -539,7 +559,7 @@ uint8_t* WebPDecodeYUV(const uint8_t* data, uint32_t data_size,
int WebPGetInfo(const uint8_t* data, uint32_t data_size,
int *width, int *height) {
const uint32_t chunk_size = CheckRIFFHeader(&data, &data_size);
const uint32_t chunk_size = WebPCheckRIFFHeader(&data, &data_size);
if (!chunk_size) {
return 0; // unsupported RIFF header
}

59
src/dec/webpi.h Normal file
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@ -0,0 +1,59 @@
// Copyright 2011 Google Inc.
//
// This code is licensed under the same terms as WebM:
// Software License Agreement: http://www.webmproject.org/license/software/
// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
// -----------------------------------------------------------------------------
//
// Internal header: WebP decoding parameters and custom IO on buffer
//
// Author: somnath@google.com (Somnath Banerjee)
#ifndef WEBP_DEC_WEBPI_H
#define WEBP_DEC_WEBPI_H
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
#include "webp/decode_vp8.h"
typedef enum { MODE_RGB = 0, MODE_RGBA = 1,
MODE_BGR = 2, MODE_BGRA = 3,
MODE_YUV = 4 } WEBP_CSP_MODE;
// Decoding output parameters.
typedef struct {
uint8_t* output; // rgb(a) or luma
uint8_t *u, *v;
uint8_t *top_y, *top_u, *top_v;
int stride; // rgb(a) stride or luma stride
int u_stride;
int v_stride;
WEBP_CSP_MODE mode;
} WebPDecParams;
// If a RIFF container is detected, validate it and skip over it. Returns
// VP8 bit-stream size if RIFF header is valid else returns 0
uint32_t WebPCheckRIFFHeader(const uint8_t** data_ptr,
uint32_t *data_size_ptr);
// Initializes VP8Io with custom setup, io and teardown functions
void WebPInitCustomIo(VP8Io* const io);
// Initializes params_out by allocating output buffer and setting the
// stride information. It also outputs width and height information of
// the WebP image. Returns 1 if succeeds.
int WebPInitDecParams(const uint8_t* data, uint32_t data_size, int* width,
int* height, WebPDecParams* const params_out);
// Verifies various size configurations (e.g stride >= width, specified
// output size <= stride * height etc.). Returns 0 if checks fail.
int WebPCheckDecParams(const VP8Io* io, const WebPDecParams* params,
int output_size, int output_u_size, int output_v_size);
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif
#endif // WEBP_DEC_WEBPI_H