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.

*/

#if !defined(__APPLE__) || defined(SDL_IMAGE_USE_COMMON_BACKEND)

/* This is a JPEG image file loading framework */

#include <stdio.h>

#include "SDL_image.h"

#ifdef LOAD_JPG

#include <jpeglib.h>

typedef JPEG_boolean boolean;

#define TRUE JPEG_TRUE

#define FALSE JPEG_FALSE

#endif

/* Define this for fast loading and not as good image quality */

/*#define FAST_JPEG*/

/* Define this for quicker (but less perfect) JPEG identification */

#define FAST_IS_JPEG

int loaded;

void *handle;

void (*jpeg_calc_output_dimensions) (j_decompress_ptr cinfo);

void (*jpeg_CreateDecompress) (j_decompress_ptr cinfo, int version, size_t structsize);

void (*jpeg_destroy_decompress) (j_decompress_ptr cinfo);

boolean (*jpeg_finish_decompress) (j_decompress_ptr cinfo);

int (*jpeg_read_header) (j_decompress_ptr cinfo, boolean require_image);

JDIMENSION (*jpeg_read_scanlines) (j_decompress_ptr cinfo, JSAMPARRAY scanlines, JDIMENSION max_lines);

boolean (*jpeg_resync_to_restart) (j_decompress_ptr cinfo, int desired);

boolean (*jpeg_start_decompress) (j_decompress_ptr cinfo);

struct jpeg_error_mgr * (*jpeg_std_error) (struct jpeg_error_mgr * err);

} lib;

#ifdef LOAD_JPG_DYNAMIC

if ( lib.loaded == 0 ) {

lib.handle = SDL_LoadObject(LOAD_JPG_DYNAMIC);

if ( lib.handle == NULL ) {

return -1;

}

lib.jpeg_calc_output_dimensions =

(void (*) (j_decompress_ptr))

SDL_LoadFunction(lib.handle, "jpeg_calc_output_dimensions");

if ( lib.jpeg_calc_output_dimensions == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

lib.jpeg_CreateDecompress =

(void (*) (j_decompress_ptr, int, size_t))

SDL_LoadFunction(lib.handle, "jpeg_CreateDecompress");

if ( lib.jpeg_CreateDecompress == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

lib.jpeg_destroy_decompress =

(void (*) (j_decompress_ptr))

SDL_LoadFunction(lib.handle, "jpeg_destroy_decompress");

if ( lib.jpeg_destroy_decompress == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

lib.jpeg_finish_decompress =

(boolean (*) (j_decompress_ptr))

SDL_LoadFunction(lib.handle, "jpeg_finish_decompress");

if ( lib.jpeg_finish_decompress == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

lib.jpeg_read_header =

(int (*) (j_decompress_ptr, boolean))

SDL_LoadFunction(lib.handle, "jpeg_read_header");

if ( lib.jpeg_read_header == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

lib.jpeg_read_scanlines =

(JDIMENSION (*) (j_decompress_ptr, JSAMPARRAY, JDIMENSION))

SDL_LoadFunction(lib.handle, "jpeg_read_scanlines");

if ( lib.jpeg_read_scanlines == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

lib.jpeg_resync_to_restart =

(boolean (*) (j_decompress_ptr, int))

SDL_LoadFunction(lib.handle, "jpeg_resync_to_restart");

if ( lib.jpeg_resync_to_restart == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

lib.jpeg_start_decompress =

(boolean (*) (j_decompress_ptr))

SDL_LoadFunction(lib.handle, "jpeg_start_decompress");

if ( lib.jpeg_start_decompress == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

lib.jpeg_std_error =

(struct jpeg_error_mgr * (*) (struct jpeg_error_mgr *))

SDL_LoadFunction(lib.handle, "jpeg_std_error");

if ( lib.jpeg_std_error == NULL ) {

SDL_UnloadObject(lib.handle);

return -1;

}

}

++lib.loaded;

return 0;

if ( lib.loaded == 0 ) {

return;

}

if ( lib.loaded == 1 ) {

SDL_UnloadObject(lib.handle);

}

--lib.loaded;

}

#else

if ( lib.loaded == 0 ) {

lib.jpeg_calc_output_dimensions = jpeg_calc_output_dimensions;

lib.jpeg_CreateDecompress = jpeg_CreateDecompress;

lib.jpeg_destroy_decompress = jpeg_destroy_decompress;

lib.jpeg_finish_decompress = jpeg_finish_decompress;

lib.jpeg_read_header = jpeg_read_header;

lib.jpeg_read_scanlines = jpeg_read_scanlines;

lib.jpeg_resync_to_restart = jpeg_resync_to_restart;

lib.jpeg_start_decompress = jpeg_start_decompress;

lib.jpeg_std_error = jpeg_std_error;

}

++lib.loaded;

return 0;

if ( lib.loaded == 0 ) {

return;

}

if ( lib.loaded == 1 ) {

}

--lib.loaded;

}

#endif /* LOAD_JPG_DYNAMIC */

/* See if an image is contained in a data source */

int IMG_isJPG(SDL_RWops *src)

{

Sint64 start;

int is_JPG;

int in_scan;

Uint8 magic[4];

/* This detection code is by Steaphan Greene <stea@cs.binghamton.edu> */

/* Blame me, not Sam, if this doesn't work right. */

/* And don't forget to report the problem to the the sdl list too! */

if ( !src )

return 0;

start = SDL_RWtell(src);

is_JPG = 0;

in_scan = 0;

if ( SDL_RWread(src, magic, 2, 1) ) {

if ( (magic[0] == 0xFF) && (magic[1] == 0xD8) ) {

is_JPG = 1;

while (is_JPG == 1) {

if(SDL_RWread(src, magic, 1, 2) != 2) {

is_JPG = 0;

} else if( (magic[0] != 0xFF) && (in_scan == 0) ) {

is_JPG = 0;

} else if( (magic[0] != 0xFF) || (magic[1] == 0xFF) ) {

/* Extra padding in JPEG (legal) */

/* or this is data and we are scanning */

SDL_RWseek(src, -1, RW_SEEK_CUR);

} else if(magic[1] == 0xD9) {

/* Got to end of good JPEG */

break;

} else if( (in_scan == 1) && (magic[1] == 0x00) ) {

/* This is an encoded 0xFF within the data */

} else if( (magic[1] >= 0xD0) && (magic[1] < 0xD9) ) {

/* These have nothing else */

} else if(SDL_RWread(src, magic+2, 1, 2) != 2) {

is_JPG = 0;

} else {

/* Yes, it's big-endian */

Sint64 innerStart;

Uint32 size;

Sint64 end;

innerStart = SDL_RWtell(src);

size = (magic[2] << 8) + magic[3];

end = SDL_RWseek(src, size-2, RW_SEEK_CUR);

if ( end != innerStart + size - 2 ) is_JPG = 0;

if ( magic[1] == 0xDA ) {

/* Now comes the actual JPEG meat */

#ifdef FAST_IS_JPEG

/* Ok, I'm convinced. It is a JPEG. */

break;

/* I'm not convinced. Prove it! */

in_scan = 1;

}

}

}

}

}

SDL_RWseek(src, start, RW_SEEK_SET);

return(is_JPG);

}

SDL_RWops *ctx;

Uint8 buffer[INPUT_BUFFER_SIZE];

} my_source_mgr;

/*

* Initialize source --- called by jpeg_read_header

* before any data is actually read.

*/

/* We don't actually need to do anything */

return;

}

/*

* Fill the input buffer --- called whenever buffer is emptied.

*/

my_source_mgr * src = (my_source_mgr *) cinfo->src;

int nbytes;

nbytes = SDL_RWread(src->ctx, src->buffer, 1, INPUT_BUFFER_SIZE);

if (nbytes <= 0) {

/* Insert a fake EOI marker */

src->buffer[0] = (Uint8) 0xFF;

src->buffer[1] = (Uint8) JPEG_EOI;

nbytes = 2;

}

src->pub.next_input_byte = src->buffer;

src->pub.bytes_in_buffer = nbytes;

return TRUE;

}

/*

* Skip data --- used to skip over a potentially large amount of

* uninteresting data (such as an APPn marker).

*

* Writers of suspendable-input applications must note that skip_input_data

* is not granted the right to give a suspension return. If the skip extends

* beyond the data currently in the buffer, the buffer can be marked empty so

* that the next read will cause a fill_input_buffer call that can suspend.

* Arranging for additional bytes to be discarded before reloading the input

* buffer is the application writer's problem.

*/

my_source_mgr * src = (my_source_mgr *) cinfo->src;

/* Just a dumb implementation for now. Could use fseek() except

* it doesn't work on pipes. Not clear that being smart is worth

* any trouble anyway --- large skips are infrequent.

*/

if (num_bytes > 0) {

while (num_bytes > (long) src->pub.bytes_in_buffer) {

num_bytes -= (long) src->pub.bytes_in_buffer;

(void) src->pub.fill_input_buffer(cinfo);

/* note we assume that fill_input_buffer will never

* return FALSE, so suspension need not be handled.

*/

}

src->pub.next_input_byte += (size_t) num_bytes;

src->pub.bytes_in_buffer -= (size_t) num_bytes;

}

}

/*

* Terminate source --- called by jpeg_finish_decompress

* after all data has been read.

*/

/* We don't actually need to do anything */

return;

}

/*

* Prepare for input from a stdio stream.

* The caller must have already opened the stream, and is responsible

* for closing it after finishing decompression.

*/

{

my_source_mgr *src;

/* The source object and input buffer are made permanent so that a series

* of JPEG images can be read from the same file by calling jpeg_stdio_src

* only before the first one. (If we discarded the buffer at the end of

* one image, we'd likely lose the start of the next one.)

* This makes it unsafe to use this manager and a different source

* manager serially with the same JPEG object. Caveat programmer.

*/

cinfo->src = (struct jpeg_source_mgr *)

(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,

src = (my_source_mgr *) cinfo->src;

}

src = (my_source_mgr *) cinfo->src;

src->pub.init_source = init_source;

src->pub.fill_input_buffer = fill_input_buffer;

src->pub.skip_input_data = skip_input_data;

src->ctx = ctx;

src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */

src->pub.next_input_byte = NULL; /* until buffer loaded */

}

struct jpeg_error_mgr errmgr;

jmp_buf escape;

};

static void my_error_exit(j_common_ptr cinfo)

{

struct my_error_mgr *err = (struct my_error_mgr *)cinfo->err;

longjmp(err->escape, 1);

}

static void output_no_message(j_common_ptr cinfo)

{

}

/* Load a JPEG type image from an SDL datasource */

SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)

{

Sint64 start;

struct jpeg_decompress_struct cinfo;

JSAMPROW rowptr[1];

SDL_Surface *volatile surface = NULL;

struct my_error_mgr jerr;

if ( !src ) {

/* The error message has been set in SDL_RWFromFile */

return NULL;

}

start = SDL_RWtell(src);

if ( !IMG_Init(IMG_INIT_JPG) ) {

return NULL;

}

/* Create a decompression structure and load the JPEG header */

cinfo.err = lib.jpeg_std_error(&jerr.errmgr);

jerr.errmgr.error_exit = my_error_exit;

jerr.errmgr.output_message = output_no_message;

if(setjmp(jerr.escape)) {

/* If we get here, libjpeg found an error */

lib.jpeg_destroy_decompress(&cinfo);

if ( surface != NULL ) {

SDL_FreeSurface(surface);

}

SDL_RWseek(src, start, RW_SEEK_SET);

IMG_SetError("JPEG loading error");

return NULL;

}

lib.jpeg_create_decompress(&cinfo);

jpeg_SDL_RW_src(&cinfo, src);

lib.jpeg_read_header(&cinfo, TRUE);

if(cinfo.num_components == 4) {

/* Set 32-bit Raw output */

cinfo.out_color_space = JCS_CMYK;

cinfo.quantize_colors = FALSE;

lib.jpeg_calc_output_dimensions(&cinfo);

/* Allocate an output surface to hold the image */

surface = SDL_CreateRGBSurface(SDL_SWSURFACE,

cinfo.output_width, cinfo.output_height, 32,

} else {

/* Set 24-bit RGB output */

cinfo.out_color_space = JCS_RGB;

cinfo.quantize_colors = FALSE;

cinfo.scale_num = 1;

cinfo.scale_denom = 1;

cinfo.dct_method = JDCT_FASTEST;

cinfo.do_fancy_upsampling = FALSE;

/* Allocate an output surface to hold the image */

surface = SDL_CreateRGBSurface(SDL_SWSURFACE,

cinfo.output_width, cinfo.output_height, 24,

0);

}

if ( surface == NULL ) {

lib.jpeg_destroy_decompress(&cinfo);

SDL_RWseek(src, start, RW_SEEK_SET);

IMG_SetError("Out of memory");

return NULL;

}

/* Decompress the image */

lib.jpeg_start_decompress(&cinfo);

while ( cinfo.output_scanline < cinfo.output_height ) {

rowptr[0] = (JSAMPROW)(Uint8 *)surface->pixels +

cinfo.output_scanline * surface->pitch;

lib.jpeg_read_scanlines(&cinfo, rowptr, (JDIMENSION) 1);

}

lib.jpeg_finish_decompress(&cinfo);

lib.jpeg_destroy_decompress(&cinfo);

return(surface);

}

#else

int IMG_InitJPG()

{

IMG_SetError("JPEG images are not supported");

return(-1);

}

void IMG_QuitJPG()

{

}

/* See if an image is contained in a data source */

int IMG_isJPG(SDL_RWops *src)

{

}

/* Load a JPEG type image from an SDL datasource */

SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)

{

}

#endif /* LOAD_JPG */

#endif /* !defined(__APPLE__) || defined(SDL_IMAGE_USE_COMMON_BACKEND) */