IMG_webp.c
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SDL_image: An example image loading library for use with SDL
Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
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*/
/* This is a WEBP image file loading framework */
#include <stdlib.h>
#include <stdio.h>
#include "SDL_image.h"
#ifdef LOAD_WEBP
/*=============================================================================
File: SDL_webp.c
Purpose: A WEBP loader for the SDL library
Revision:
Created by: Michael Bonfils (Murlock) (26 November 2011)
murlock42@gmail.com
=============================================================================*/
#include "SDL_endian.h"
#ifdef macintosh
#define MACOS
#endif
#include <webp/decode.h>
static struct {
int loaded;
void *handle;
int/*VP8StatuCode*/ (*webp_get_features_internal) (const uint8_t *data, uint32_t data_size, WebPBitstreamFeatures* const features, int decoder_abi_version);
uint8_t* (*webp_decode_rgb_into) (const uint8_t* data, uint32_t data_size, uint8_t* output_buffer, int output_buffer_size, int output_stride);
uint8_t* (*webp_decode_rgba_into) (const uint8_t* data, uint32_t data_size, uint8_t* output_buffer, int output_buffer_size, int output_stride);
} lib;
#ifdef LOAD_WEBP_DYNAMIC
int IMG_InitWEBP()
{
if ( lib.loaded == 0 ) {
lib.handle = SDL_LoadObject(LOAD_WEBP_DYNAMIC);
if ( lib.handle == NULL ) {
return -1;
}
lib.webp_get_features_internal =
( int (*) (const uint8_t *, uint32_t, WebPBitstreamFeatures* const, int) )
SDL_LoadFunction(lib.handle, "WebPGetFeaturesInternal" );
if ( lib.webp_get_features_internal == NULL ) {
SDL_UnloadObject(lib.handle);
return -1;
}
lib.webp_decode_rgb_into =
( uint8_t* (*) (const uint8_t*, uint32_t, uint8_t*, int, int ) )
SDL_LoadFunction(lib.handle, "WebPDecodeRGBInto" );
if ( lib.webp_decode_rgb_into == NULL ) {
SDL_UnloadObject(lib.handle);
return -1;
}
lib.webp_decode_rgba_into =
( uint8_t* (*) (const uint8_t*, uint32_t, uint8_t*, int, int ) )
SDL_LoadFunction(lib.handle, "WebPDecodeRGBInto" );
if ( lib.webp_decode_rgba_into == NULL ) {
SDL_UnloadObject(lib.handle);
return -1;
}
}
++lib.loaded;
return 0;
}
void IMG_QuitWEBP()
{
if ( lib.loaded == 0 ) {
return;
}
if ( lib.loaded == 1 ) {
SDL_UnloadObject(lib.handle);
}
--lib.loaded;
}
#else
int IMG_InitWEBP()
{
if ( lib.loaded == 0 ) {
lib.webp_get_features_internal = WebPGetFeaturesInternal;
lib.webp_decode_rgb_into = WebPDecodeRGBInto;
lib.webp_decode_rgba_into = WebPDecodeRGBAInto;
}
++lib.loaded;
return 0;
}
void IMG_QuitWEBP()
{
if ( lib.loaded == 0 ) {
return;
}
if ( lib.loaded == 1 ) {
}
--lib.loaded;
}
#endif /* LOAD_WEBP_DYNAMIC */
static int webp_getinfo( SDL_RWops *src, int *datasize ) {
int start;
int is_WEBP;
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int data;
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Uint8 magic[20];
if ( !src )
return 0;
start = SDL_RWtell(src);
is_WEBP = 0;
if ( SDL_RWread(src, magic, 1, sizeof(magic)) == sizeof(magic) ) {
if ( magic[ 0] == 'R' &&
magic[ 1] == 'I' &&
magic[ 2] == 'F' &&
magic[ 3] == 'F' &&
magic[ 8] == 'W' &&
magic[ 9] == 'E' &&
magic[10] == 'B' &&
magic[11] == 'P' &&
magic[12] == 'V' &&
magic[13] == 'P' &&
magic[14] == '8' &&
magic[15] == ' ' ) {
is_WEBP = 1;
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data = magic[16] | magic[17]<<8 | magic[18]<<16 | magic[19]<<24;
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if ( datasize )
*datasize = data;
}
}
SDL_RWseek(src, start, RW_SEEK_SET);
return(is_WEBP);
}
/* See if an image is contained in a data source */
int IMG_isWEBP(SDL_RWops *src)
{
return webp_getinfo( src, NULL );
}
SDL_Surface *IMG_LoadWEBP_RW(SDL_RWops *src)
{
int start;
const char *error = NULL;
SDL_Surface *volatile surface = NULL;
Uint32 Rmask;
Uint32 Gmask;
Uint32 Bmask;
Uint32 Amask;
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WebPBitstreamFeatures features;
int raw_data_size;
uint8_t *raw_data;
int r;
uint8_t *ret;
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if ( !src ) {
/* The error message has been set in SDL_RWFromFile */
return NULL;
}
start = SDL_RWtell(src);
if ( !IMG_Init(IMG_INIT_WEBP) ) {
goto error;
}
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raw_data_size = -1;
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if ( !webp_getinfo( src, &raw_data_size ) ) {
error = "Invalid WEBP";
goto error;
}
// skip header
SDL_RWseek(src, start+20, RW_SEEK_SET );
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raw_data = (uint8_t*) malloc( raw_data_size );
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if ( raw_data == NULL ) {
error = "Failed to allocate enought buffer for WEBP";
goto error;
}
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r = SDL_RWread(src, raw_data, 1, raw_data_size );
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if ( r != raw_data_size ) {
error = "Failed to read WEBP";
goto error;
}
#if 0
// extract size of picture, not interesting since we don't know about alpha channel
int width = -1, height = -1;
if ( !WebPGetInfo( raw_data, raw_data_size, &width, &height ) ) {
printf("WebPGetInfo has failed\n" );
return NULL;
}
#endif
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if ( lib.webp_get_features_internal( raw_data, raw_data_size, &features, WEBP_DECODER_ABI_VERSION ) != VP8_STATUS_OK ) {
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error = "WebPGetFeatures has failed";
return NULL;
}
/* Check if it's ok !*/
Rmask = 0x000000FF;
Gmask = 0x0000FF00;
Bmask = 0x00FF0000;
Amask = features.has_alpha?0xFF000001:0;
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surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
features.width, features.height,
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features.has_alpha?32:24, Rmask,Gmask,Bmask,Amask);
if ( surface == NULL ) {
error = "Failed to allocate SDL_Surface";
goto error;
}
if ( features.has_alpha ) {
ret = lib.webp_decode_rgba_into( raw_data, raw_data_size, surface->pixels, surface->pitch * surface->h, surface->pitch );
} else {
ret = lib.webp_decode_rgb_into( raw_data, raw_data_size, surface->pixels, surface->pitch * surface->h, surface->pitch );
}
if ( !ret ) {
error = "Failed to decode WEBP";
goto error;
}
return surface;
error:
if ( surface ) {
SDL_FreeSurface( surface );
}
if ( raw_data ) {
free( raw_data );
}
if ( error ) {
IMG_SetError( error );
}
SDL_RWseek(src, start, RW_SEEK_SET);
return(NULL);
}
#else
int IMG_InitWEBP()
{
IMG_SetError("WEBP images are not supported");
return(-1);
}
void IMG_QuitWEBP()
{
}
/* See if an image is contained in a data source */
int IMG_isWEBP(SDL_RWops *src)
{
return(0);
}
/* Load a WEBP type image from an SDL datasource */
SDL_Surface *IMG_LoadWEBP_RW(SDL_RWops *src)
{
return(NULL);
}
#endif /* LOAD_WEBP */