1 /*
2 SDL_image: An example image loading library for use with SDL
3 Copyright (C) 1997-2019 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 "SDL_image.h"
25
26 #ifdef LOAD_XV
27
get_line(SDL_RWops * src,char * line,int size)28 static int get_line(SDL_RWops *src, char *line, int size)
29 {
30 while ( size > 0 ) {
31 if ( SDL_RWread(src, line, 1, 1) <= 0 ) {
32 return -1;
33 }
34 if ( *line == '\r' ) {
35 continue;
36 }
37 if ( *line == '\n' ) {
38 *line = '\0';
39 return 0;
40 }
41 ++line;
42 --size;
43 }
44 /* Out of space for the line */
45 return -1;
46 }
47
get_header(SDL_RWops * src,int * w,int * h)48 static int get_header(SDL_RWops *src, int *w, int *h)
49 {
50 char line[1024];
51
52 *w = 0;
53 *h = 0;
54
55 /* Check the header magic */
56 if ( (get_line(src, line, sizeof(line)) < 0) ||
57 (SDL_memcmp(line, "P7 332", 6) != 0) ) {
58 return -1;
59 }
60
61 /* Read the header */
62 while ( get_line(src, line, sizeof(line)) == 0 ) {
63 if ( SDL_memcmp(line, "#BUILTIN:", 9) == 0 ) {
64 /* Builtin image, no data */
65 break;
66 }
67 if ( SDL_memcmp(line, "#END_OF_COMMENTS", 16) == 0 ) {
68 if ( get_line(src, line, sizeof(line)) == 0 ) {
69 SDL_sscanf(line, "%d %d", w, h);
70 if ( *w >= 0 && *h >= 0 ) {
71 return 0;
72 }
73 }
74 break;
75 }
76 }
77 /* No image data */
78 return -1;
79 }
80
81 /* See if an image is contained in a data source */
IMG_isXV(SDL_RWops * src)82 int IMG_isXV(SDL_RWops *src)
83 {
84 Sint64 start;
85 int is_XV;
86 int w, h;
87
88 if ( !src )
89 return 0;
90 start = SDL_RWtell(src);
91 is_XV = 0;
92 if ( get_header(src, &w, &h) == 0 ) {
93 is_XV = 1;
94 }
95 SDL_RWseek(src, start, RW_SEEK_SET);
96 return(is_XV);
97 }
98
99 /* Load a XV thumbnail image from an SDL datasource */
IMG_LoadXV_RW(SDL_RWops * src)100 SDL_Surface *IMG_LoadXV_RW(SDL_RWops *src)
101 {
102 Sint64 start;
103 const char *error = NULL;
104 SDL_Surface *surface = NULL;
105 int w, h;
106 Uint8 *pixels;
107
108 if ( !src ) {
109 /* The error message has been set in SDL_RWFromFile */
110 return NULL;
111 }
112 start = SDL_RWtell(src);
113
114 /* Read the header */
115 if ( get_header(src, &w, &h) < 0 ) {
116 error = "Unsupported image format";
117 goto done;
118 }
119
120 /* Create the 3-3-2 indexed palette surface */
121 surface = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 8, 0xe0, 0x1c, 0x03, 0);
122 if ( surface == NULL ) {
123 error = "Out of memory";
124 goto done;
125 }
126
127 /* Load the image data */
128 for ( pixels = (Uint8 *)surface->pixels; h > 0; --h ) {
129 if ( SDL_RWread(src, pixels, w, 1) <= 0 ) {
130 error = "Couldn't read image data";
131 goto done;
132 }
133 pixels += surface->pitch;
134 }
135
136 done:
137 if ( error ) {
138 SDL_RWseek(src, start, RW_SEEK_SET);
139 if ( surface ) {
140 SDL_FreeSurface(surface);
141 surface = NULL;
142 }
143 IMG_SetError("%s", error);
144 }
145 return surface;
146 }
147
148 #else
149
150 /* See if an image is contained in a data source */
IMG_isXV(SDL_RWops * src)151 int IMG_isXV(SDL_RWops *src)
152 {
153 return(0);
154 }
155
156 /* Load a XXX type image from an SDL datasource */
IMG_LoadXV_RW(SDL_RWops * src)157 SDL_Surface *IMG_LoadXV_RW(SDL_RWops *src)
158 {
159 return(NULL);
160 }
161
162 #endif /* LOAD_XV */
163