Change to the linux kernel coding style
[wmaker-crm.git] / wrlib / jpeg.c
1 /* jpeg.c - load JPEG image from file
2 *
3 * Raster graphics library
4 *
5 * Copyright (c) 1997-2003 Alfredo K. Kojima
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
16 *
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the Free
19 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22 #include <config.h>
23
24 /* Avoid a compiler warning */
25 #undef HAVE_STDLIB_H
26
27 #ifdef USE_JPEG
28
29 #include <stdlib.h>
30 #include <stdio.h>
31 #include <string.h>
32
33 #include <jpeglib.h>
34
35 #include "wraster.h"
36
37 /*
38 * <setjmp.h> is used for the optional error recovery mechanism shown in
39 * the second part of the example.
40 */
41
42 #include <setjmp.h>
43
44 /*
45 * ERROR HANDLING:
46 *
47 * The JPEG library's standard error handler (jerror.c) is divided into
48 * several "methods" which you can override individually. This lets you
49 * adjust the behavior without duplicating a lot of code, which you might
50 * have to update with each future release.
51 *
52 * Our example here shows how to override the "error_exit" method so that
53 * control is returned to the library's caller when a fatal error occurs,
54 * rather than calling exit() as the standard error_exit method does.
55 *
56 * We use C's setjmp/longjmp facility to return control. This means that the
57 * routine which calls the JPEG library must first execute a setjmp() call to
58 * establish the return point. We want the replacement error_exit to do a
59 * longjmp(). But we need to make the setjmp buffer accessible to the
60 * error_exit routine. To do this, we make a private extension of the
61 * standard JPEG error handler object. (If we were using C++, we'd say we
62 * were making a subclass of the regular error handler.)
63 *
64 * Here's the extended error handler struct:
65 */
66
67 struct my_error_mgr {
68 struct jpeg_error_mgr pub; /* "public" fields */
69
70 jmp_buf setjmp_buffer; /* for return to caller */
71 };
72
73 typedef struct my_error_mgr *my_error_ptr;
74
75 /*
76 * Here's the routine that will replace the standard error_exit method:
77 */
78
79 static void my_error_exit(j_common_ptr cinfo)
80 {
81 /* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
82 my_error_ptr myerr = (my_error_ptr) cinfo->err;
83
84 /* Always display the message. */
85 /* We could postpone this until after returning, if we chose. */
86 (*cinfo->err->output_message) (cinfo);
87
88 /* Return control to the setjmp point */
89 longjmp(myerr->setjmp_buffer, 1);
90 }
91
92 RImage *RLoadJPEG(RContext * context, char *file_name, int index)
93 {
94 RImage *image = NULL;
95 struct jpeg_decompress_struct cinfo;
96 int i;
97 unsigned char *ptr;
98 JSAMPROW buffer[1], bptr;
99 FILE *file;
100 /* We use our private extension JPEG error handler.
101 * Note that this struct must live as long as the main JPEG parameter
102 * struct, to avoid dangling-pointer problems.
103 */
104 struct my_error_mgr jerr;
105
106 file = fopen(file_name, "rb");
107 if (!file) {
108 RErrorCode = RERR_OPEN;
109 return NULL;
110 }
111
112 cinfo.err = jpeg_std_error(&jerr.pub);
113 jerr.pub.error_exit = my_error_exit;
114 /* Establish the setjmp return context for my_error_exit to use. */
115 if (setjmp(jerr.setjmp_buffer)) {
116 /* If we get here, the JPEG code has signaled an error.
117 * We need to clean up the JPEG object, close the input file, and return.
118 */
119 jpeg_destroy_decompress(&cinfo);
120 fclose(file);
121 return NULL;
122 }
123
124 jpeg_create_decompress(&cinfo);
125
126 jpeg_stdio_src(&cinfo, file);
127
128 jpeg_read_header(&cinfo, TRUE);
129
130 if (cinfo.image_width < 1 || cinfo.image_height < 1) {
131 RErrorCode = RERR_BADIMAGEFILE;
132 goto bye;
133 }
134
135 bptr = buffer[0] = (JSAMPROW) malloc(cinfo.image_width * cinfo.num_components);
136 if (!buffer[0]) {
137 RErrorCode = RERR_NOMEMORY;
138 goto bye;
139 }
140
141 if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
142 cinfo.out_color_space = JCS_GRAYSCALE;
143 } else
144 cinfo.out_color_space = JCS_RGB;
145 cinfo.quantize_colors = FALSE;
146 cinfo.do_fancy_upsampling = FALSE;
147 cinfo.do_block_smoothing = FALSE;
148 jpeg_calc_output_dimensions(&cinfo);
149
150 if (context->flags.optimize_for_speed)
151 image = RCreateImage(cinfo.image_width, cinfo.image_height, True);
152 else
153 image = RCreateImage(cinfo.image_width, cinfo.image_height, False);
154
155 if (!image) {
156 RErrorCode = RERR_NOMEMORY;
157 goto bye;
158 }
159 jpeg_start_decompress(&cinfo);
160
161 ptr = image->data;
162
163 if (cinfo.out_color_space == JCS_RGB) {
164 if (context->flags.optimize_for_speed) {
165 while (cinfo.output_scanline < cinfo.output_height) {
166 jpeg_read_scanlines(&cinfo, buffer, (JDIMENSION) 1);
167 bptr = buffer[0];
168 for (i = 0; i < cinfo.image_width; i++) {
169 *ptr++ = *bptr++;
170 *ptr++ = *bptr++;
171 *ptr++ = *bptr++;
172 ptr++; /* skip alpha channel */
173 }
174 }
175 } else {
176 while (cinfo.output_scanline < cinfo.output_height) {
177 jpeg_read_scanlines(&cinfo, buffer, (JDIMENSION) 1);
178 bptr = buffer[0];
179 memcpy(ptr, bptr, cinfo.image_width * 3);
180 ptr += cinfo.image_width * 3;
181 }
182 }
183 } else {
184 while (cinfo.output_scanline < cinfo.output_height) {
185 jpeg_read_scanlines(&cinfo, buffer, (JDIMENSION) 1);
186 bptr = buffer[0];
187 for (i = 0; i < cinfo.image_width; i++) {
188 *ptr++ = *bptr;
189 *ptr++ = *bptr;
190 *ptr++ = *bptr++;
191 }
192 }
193 }
194
195 jpeg_finish_decompress(&cinfo);
196
197 bye:
198 jpeg_destroy_decompress(&cinfo);
199
200 fclose(file);
201
202 if (buffer[0])
203 free(buffer[0]);
204
205 return image;
206 }
207
208 #endif /* USE_JPEG */