IMG_webp.c
author Sam Lantinga <slouken@libsdl.org>
Tue, 21 May 2013 21:24:32 -0700
changeset 368 8a61842d00ce
parent 360 3d002acf103d
child 378 f83e70f2ec6c
permissions -rw-r--r--
Cleaned up whitespace for the 2.0.0 release
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/*
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  SDL_image:  An example image loading library for use with SDL
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  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
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  This software is provided 'as-is', without any express or implied
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  warranty.  In no event will the authors be held liable for any damages
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  arising from the use of this software.
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  Permission is granted to anyone to use this software for any purpose,
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  including commercial applications, and to alter it and redistribute it
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  freely, subject to the following restrictions:
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  1. The origin of this software must not be misrepresented; you must not
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     claim that you wrote the original software. If you use this software
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     in a product, an acknowledgment in the product documentation would be
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     appreciated but is not required.
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  2. Altered source versions must be plainly marked as such, and must not be
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     misrepresented as being the original software.
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  3. This notice may not be removed or altered from any source distribution.
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*/
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/* This is a WEBP image file loading framework */
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#include <stdlib.h>
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#include <stdio.h>
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#include "SDL_image.h"
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#ifdef LOAD_WEBP
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/*=============================================================================
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        File: SDL_webp.c
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     Purpose: A WEBP loader for the SDL library
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    Revision:
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  Created by: Michael Bonfils (Murlock) (26 November 2011)
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              murlock42@gmail.com
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=============================================================================*/
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#include "SDL_endian.h"
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#ifdef macintosh
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#define MACOS
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#endif
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#include <webp/decode.h>
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static struct {
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    int loaded;
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    void *handle;
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    int/*VP8StatuCode*/ (*webp_get_features_internal) (const uint8_t *data, uint32_t data_size, WebPBitstreamFeatures* const features, int decoder_abi_version);
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    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);
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    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);
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} lib;
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#ifdef LOAD_WEBP_DYNAMIC
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int IMG_InitWEBP()
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{
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    if ( lib.loaded == 0 ) {
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        lib.handle = SDL_LoadObject(LOAD_WEBP_DYNAMIC);
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        if ( lib.handle == NULL ) {
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            return -1;
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        }
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        lib.webp_get_features_internal =
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            ( int (*) (const uint8_t *, uint32_t, WebPBitstreamFeatures* const, int) )
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            SDL_LoadFunction(lib.handle, "WebPGetFeaturesInternal" );
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        if ( lib.webp_get_features_internal == NULL ) {
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            SDL_UnloadObject(lib.handle);
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            return -1;
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        }
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        lib.webp_decode_rgb_into =
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            ( uint8_t* (*) (const uint8_t*, uint32_t, uint8_t*, int, int ) )
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            SDL_LoadFunction(lib.handle, "WebPDecodeRGBInto" );
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        if ( lib.webp_decode_rgb_into == NULL ) {
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            SDL_UnloadObject(lib.handle);
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            return -1;
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        }
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        lib.webp_decode_rgba_into =
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            ( uint8_t* (*) (const uint8_t*, uint32_t, uint8_t*, int, int ) )
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            SDL_LoadFunction(lib.handle, "WebPDecodeRGBAInto" );
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        if ( lib.webp_decode_rgba_into == NULL ) {
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            SDL_UnloadObject(lib.handle);
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            return -1;
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        }
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    }
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    ++lib.loaded;
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    return 0;
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}
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void IMG_QuitWEBP()
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{
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    if ( lib.loaded == 0 ) {
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        return;
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    }
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    if ( lib.loaded == 1 ) {
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        SDL_UnloadObject(lib.handle);
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    }
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    --lib.loaded;
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}
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#else
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int IMG_InitWEBP()
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{
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    if ( lib.loaded == 0 ) {
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        lib.webp_get_features_internal = WebPGetFeaturesInternal;
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        lib.webp_decode_rgb_into = WebPDecodeRGBInto;
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        lib.webp_decode_rgba_into = WebPDecodeRGBAInto;
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    }
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    ++lib.loaded;
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    return 0;
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}
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void IMG_QuitWEBP()
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{
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    if ( lib.loaded == 0 ) {
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        return;
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    }
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    if ( lib.loaded == 1 ) {
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    }
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    --lib.loaded;
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}
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#endif /* LOAD_WEBP_DYNAMIC */
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static int webp_getinfo( SDL_RWops *src, int *datasize ) {
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    Sint64 start;
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    int is_WEBP;
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    Uint8 magic[20];
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    if ( !src )
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        return 0;
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    start = SDL_RWtell(src);
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    is_WEBP = 0;
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    if ( SDL_RWread(src, magic, 1, sizeof(magic)) == sizeof(magic) ) {
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        if ( magic[ 0] == 'R' &&
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                     magic[ 1] == 'I' &&
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                     magic[ 2] == 'F' &&
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                     magic[ 3] == 'F' &&
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                                         magic[ 8] == 'W' &&
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                                         magic[ 9] == 'E' &&
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                                         magic[10] == 'B' &&
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                                         magic[11] == 'P' &&
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                                         magic[12] == 'V' &&
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                                         magic[13] == 'P' &&
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                                         magic[14] == '8' &&
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#if WEBP_DECODER_ABI_VERSION < 0x0003 /* old versions don't support WEBPVP8X and WEBPVP8L */
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                                         magic[15] == ' ') {
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#else
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                                         (magic[15] == ' ' || magic[15] == 'X' || magic[15] == 'L')) {
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#endif
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            is_WEBP = 1;
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            if ( datasize ) {
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                *datasize = SDL_RWseek(src, 0, SEEK_END);
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            }
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        }
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    }
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    SDL_RWseek(src, start, RW_SEEK_SET);
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    return(is_WEBP);
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}
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/* See if an image is contained in a data source */
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int IMG_isWEBP(SDL_RWops *src)
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{
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    return webp_getinfo( src, NULL );
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}
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SDL_Surface *IMG_LoadWEBP_RW(SDL_RWops *src)
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{
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    Sint64 start;
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    const char *error = NULL;
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    SDL_Surface *volatile surface = NULL;
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    Uint32 Rmask;
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    Uint32 Gmask;
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    Uint32 Bmask;
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    Uint32 Amask;
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    WebPBitstreamFeatures features;
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    int raw_data_size;
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    uint8_t *raw_data = NULL;
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    int r, s;
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    uint8_t *ret;
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    if ( !src ) {
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        /* The error message has been set in SDL_RWFromFile */
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        return NULL;
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    }
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    start = SDL_RWtell(src);
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    if ( !IMG_Init(IMG_INIT_WEBP) ) {
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        goto error;
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    }
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    raw_data_size = -1;
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    if ( !webp_getinfo( src, &raw_data_size ) ) {
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        error = "Invalid WEBP";
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        goto error;
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    }
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    // seek to start of file
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    SDL_RWseek(src, 0, RW_SEEK_SET );
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    raw_data = (uint8_t*) SDL_malloc( raw_data_size );
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    if ( raw_data == NULL ) {
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        error = "Failed to allocate enought buffer for WEBP";
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        goto error;
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    }
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    r = SDL_RWread(src, raw_data, 1, raw_data_size );
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    if ( r != raw_data_size ) {
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        error = "Failed to read WEBP";
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        goto error;
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    }
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#if 0
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    // extract size of picture, not interesting since we don't know about alpha channel
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    int width = -1, height = -1;
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    if ( !WebPGetInfo( raw_data, raw_data_size, &width, &height ) ) {
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        printf("WebPGetInfo has failed\n" );
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        return NULL;
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    }
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#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";
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        goto error;
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    }
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    /* Check if it's ok !*/
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#if SDL_BYTEORDER == SDL_LIL_ENDIAN
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    Rmask = 0x000000FF;
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    Gmask = 0x0000FF00;
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    Bmask = 0x00FF0000;
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    Amask = (features.has_alpha) ? 0xFF000000 : 0;
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#else
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    s = (features.has_alpha) ? 0 : 8;
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    Rmask = 0xFF000000 >> s;
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    Gmask = 0x00FF0000 >> s;
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    Bmask = 0x0000FF00 >> s;
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    Amask = 0x000000FF >> s;
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#endif
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    surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
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            features.width, features.height,
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            features.has_alpha?32:24, Rmask,Gmask,Bmask,Amask);
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    if ( surface == NULL ) {
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        error = "Failed to allocate SDL_Surface";
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        goto error;
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    }
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    if ( features.has_alpha ) {
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        ret = lib.webp_decode_rgba_into( raw_data, raw_data_size, (uint8_t *)surface->pixels, surface->pitch * surface->h,  surface->pitch );
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    } else {
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        ret = lib.webp_decode_rgb_into( raw_data, raw_data_size, (uint8_t *)surface->pixels, surface->pitch * surface->h,  surface->pitch );
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    }
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    if ( !ret ) {
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        error = "Failed to decode WEBP";
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        goto error;
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    }
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    return surface;
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error:
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    if ( surface ) {
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        SDL_FreeSurface( surface );
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    }
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    if ( raw_data ) {
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        SDL_free( raw_data );
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    }
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    if ( error ) {
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        IMG_SetError( error );
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    }
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    SDL_RWseek(src, start, RW_SEEK_SET);
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    return(NULL);
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}
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#else
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int IMG_InitWEBP()
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{
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    IMG_SetError("WEBP images are not supported");
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    return(-1);
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}
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void IMG_QuitWEBP()
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{
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}
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/* See if an image is contained in a data source */
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int IMG_isWEBP(SDL_RWops *src)
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{
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    return(0);
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}
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/* Load a WEBP type image from an SDL datasource */
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SDL_Surface *IMG_LoadWEBP_RW(SDL_RWops *src)
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{
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    return(NULL);
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}
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#endif /* LOAD_WEBP */