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IMG_xv.c
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IMG_xv.c
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/*
SDL_image: An example image loading library for use with SDL
Copyright (C) 1997-2009 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
/* This is a XV thumbnail image file loading framework */
#include <stdio.h>
#include <string.h>
#include "SDL_image.h"
#ifdef LOAD_XV
static int get_line(SDL_RWops *src, char *line, int size)
{
while ( size > 0 ) {
if ( SDL_RWread(src, line, 1, 1) <= 0 ) {
return -1;
}
if ( *line == '\r' ) {
continue;
}
if ( *line == '\n' ) {
*line = '\0';
return 0;
}
++line;
--size;
}
/* Out of space for the line */
return -1;
}
static int get_header(SDL_RWops *src, int *w, int *h)
{
char line[1024];
*w = 0;
*h = 0;
/* Check the header magic */
if ( (get_line(src, line, sizeof(line)) < 0) ||
(memcmp(line, "P7 332", 6) != 0) ) {
return -1;
}
/* Read the header */
while ( get_line(src, line, sizeof(line)) == 0 ) {
if ( memcmp(line, "#BUILTIN:", 9) == 0 ) {
/* Builtin image, no data */
break;
}
if ( memcmp(line, "#END_OF_COMMENTS", 16) == 0 ) {
if ( get_line(src, line, sizeof(line)) == 0 ) {
sscanf(line, "%d %d", w, h);
if ( *w >= 0 && *h >= 0 ) {
return 0;
}
}
break;
}
}
/* No image data */
return -1;
}
/* See if an image is contained in a data source */
int IMG_isXV(SDL_RWops *src)
{
int start;
int is_XV;
int w, h;
if ( !src )
return 0;
start = SDL_RWtell(src);
is_XV = 0;
if ( get_header(src, &w, &h) == 0 ) {
is_XV = 1;
}
SDL_RWseek(src, start, SEEK_SET);
return(is_XV);
}
/* Load a XV thumbnail image from an SDL datasource */
SDL_Surface *IMG_LoadXV_RW(SDL_RWops *src)
{
int start;
const char *error = NULL;
SDL_Surface *surface = NULL;
int w, h;
Uint8 *pixels;
if ( !src ) {
/* The error message has been set in SDL_RWFromFile */
return NULL;
}
start = SDL_RWtell(src);
/* Read the header */
if ( get_header(src, &w, &h) < 0 ) {
error = "Unsupported image format";
goto done;
}
/* Create the 3-3-2 indexed palette surface */
surface = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 8, 0xe0, 0x1c, 0x03, 0);
if ( surface == NULL ) {
error = "Out of memory";
goto done;
}
/* Load the image data */
for ( pixels = (Uint8 *)surface->pixels; h > 0; --h ) {
if ( SDL_RWread(src, pixels, w, 1) <= 0 ) {
error = "Couldn't read image data";
goto done;
}
pixels += surface->pitch;
}
done:
if ( error ) {
SDL_RWseek(src, start, SEEK_SET);
if ( surface ) {
SDL_FreeSurface(surface);
surface = NULL;
}
IMG_SetError(error);
}
return surface;
}
#else
/* See if an image is contained in a data source */
int IMG_isXV(SDL_RWops *src)
{
return(0);
}
/* Load a XXX type image from an SDL datasource */
SDL_Surface *IMG_LoadXV_RW(SDL_RWops *src)
{
return(NULL);
}
#endif /* LOAD_XV */