IMG_xv.c
author Sam Lantinga <slouken@libsdl.org>
Sun, 15 Jun 2014 13:16:42 -0700
changeset 451 48116d511e5d
parent 368 8a61842d00ce
child 486 7bb8af91e887
permissions -rw-r--r--
Fixed format warnings: format not a string literal and no format arguments
     1 /*
     2   SDL_image:  An example image loading library for use with SDL
     3   Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 
    22 /* This is a XV thumbnail image file loading framework */
    23 
    24 #include <stdio.h>
    25 #include <string.h>
    26 
    27 #include "SDL_image.h"
    28 
    29 #ifdef LOAD_XV
    30 
    31 static int get_line(SDL_RWops *src, char *line, int size)
    32 {
    33     while ( size > 0 ) {
    34         if ( SDL_RWread(src, line, 1, 1) <= 0 ) {
    35             return -1;
    36         }
    37         if ( *line == '\r' ) {
    38             continue;
    39         }
    40         if ( *line == '\n' ) {
    41             *line = '\0';
    42             return 0;
    43         }
    44         ++line;
    45         --size;
    46     }
    47     /* Out of space for the line */
    48     return -1;
    49 }
    50 
    51 static int get_header(SDL_RWops *src, int *w, int *h)
    52 {
    53     char line[1024];
    54 
    55     *w = 0;
    56     *h = 0;
    57 
    58     /* Check the header magic */
    59     if ( (get_line(src, line, sizeof(line)) < 0) ||
    60          (SDL_memcmp(line, "P7 332", 6) != 0) ) {
    61         return -1;
    62     }
    63 
    64     /* Read the header */
    65     while ( get_line(src, line, sizeof(line)) == 0 ) {
    66         if ( SDL_memcmp(line, "#BUILTIN:", 9) == 0 ) {
    67             /* Builtin image, no data */
    68             break;
    69         }
    70         if ( SDL_memcmp(line, "#END_OF_COMMENTS", 16) == 0 ) {
    71             if ( get_line(src, line, sizeof(line)) == 0 ) {
    72                 SDL_sscanf(line, "%d %d", w, h);
    73                 if ( *w >= 0 && *h >= 0 ) {
    74                     return 0;
    75                 }
    76             }
    77             break;
    78         }
    79     }
    80     /* No image data */
    81     return -1;
    82 }
    83 
    84 /* See if an image is contained in a data source */
    85 int IMG_isXV(SDL_RWops *src)
    86 {
    87     Sint64 start;
    88     int is_XV;
    89     int w, h;
    90 
    91     if ( !src )
    92         return 0;
    93     start = SDL_RWtell(src);
    94     is_XV = 0;
    95     if ( get_header(src, &w, &h) == 0 ) {
    96         is_XV = 1;
    97     }
    98     SDL_RWseek(src, start, RW_SEEK_SET);
    99     return(is_XV);
   100 }
   101 
   102 /* Load a XV thumbnail image from an SDL datasource */
   103 SDL_Surface *IMG_LoadXV_RW(SDL_RWops *src)
   104 {
   105     Sint64 start;
   106     const char *error = NULL;
   107     SDL_Surface *surface = NULL;
   108     int w, h;
   109     Uint8 *pixels;
   110 
   111     if ( !src ) {
   112         /* The error message has been set in SDL_RWFromFile */
   113         return NULL;
   114     }
   115     start = SDL_RWtell(src);
   116 
   117     /* Read the header */
   118     if ( get_header(src, &w, &h) < 0 ) {
   119         error = "Unsupported image format";
   120         goto done;
   121     }
   122 
   123     /* Create the 3-3-2 indexed palette surface */
   124     surface = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 8, 0xe0, 0x1c, 0x03, 0);
   125     if ( surface == NULL ) {
   126         error = "Out of memory";
   127         goto done;
   128     }
   129 
   130     /* Load the image data */
   131     for ( pixels = (Uint8 *)surface->pixels; h > 0; --h ) {
   132         if ( SDL_RWread(src, pixels, w, 1) <= 0 ) {
   133             error = "Couldn't read image data";
   134             goto done;
   135         }
   136         pixels += surface->pitch;
   137     }
   138 
   139 done:
   140     if ( error ) {
   141         SDL_RWseek(src, start, RW_SEEK_SET);
   142         if ( surface ) {
   143             SDL_FreeSurface(surface);
   144             surface = NULL;
   145         }
   146         IMG_SetError("%s", error);
   147     }
   148     return surface;
   149 }
   150 
   151 #else
   152 
   153 /* See if an image is contained in a data source */
   154 int IMG_isXV(SDL_RWops *src)
   155 {
   156     return(0);
   157 }
   158 
   159 /* Load a XXX type image from an SDL datasource */
   160 SDL_Surface *IMG_LoadXV_RW(SDL_RWops *src)
   161 {
   162     return(NULL);
   163 }
   164 
   165 #endif /* LOAD_XV */