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comparison mupdf-source/thirdparty/libjpeg/wrppm.c @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 /*
2 * wrppm.c
3 *
4 * Copyright (C) 1991-1996, Thomas G. Lane.
5 * Modified 2009-2020 by Guido Vollbeding.
6 * This file is part of the Independent JPEG Group's software.
7 * For conditions of distribution and use, see the accompanying README file.
8 *
9 * This file contains routines to write output images in PPM/PGM format.
10 * The extended 2-byte-per-sample raw PPM/PGM formats are supported.
11 * The PBMPLUS library is NOT required to compile this software
12 * (but it is highly useful as a set of PPM image manipulation programs).
13 *
14 * These routines may need modification for non-Unix environments or
15 * specialized applications. As they stand, they assume output to
16 * an ordinary stdio stream.
17 */
18
19 #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
20
21 #ifdef PPM_SUPPORTED
22
23
24 /*
25 * For 12-bit JPEG data, we either downscale the values to 8 bits
26 * (to write standard byte-per-sample PPM/PGM files), or output
27 * nonstandard word-per-sample PPM/PGM files. Downscaling is done
28 * if PPM_NORAWWORD is defined (this can be done in the Makefile
29 * or in jconfig.h).
30 * (When the core library supports data precision reduction, a cleaner
31 * implementation will be to ask for that instead.)
32 */
33
34 #if BITS_IN_JSAMPLE == 8
35 #define PUTPPMSAMPLE(ptr,v) *ptr++ = (char) (v)
36 #define BYTESPERSAMPLE 1
37 #define PPM_MAXVAL 255
38 #else
39 #ifdef PPM_NORAWWORD
40 #define PUTPPMSAMPLE(ptr,v) *ptr++ = (char) ((v) >> (BITS_IN_JSAMPLE-8))
41 #define BYTESPERSAMPLE 1
42 #define PPM_MAXVAL 255
43 #else
44 /* The word-per-sample format always puts the MSB first. */
45 #define PUTPPMSAMPLE(ptr,v) \
46 { register int val_ = v; \
47 *ptr++ = (char) ((val_ >> 8) & 0xFF); \
48 *ptr++ = (char) (val_ & 0xFF); \
49 }
50 #define BYTESPERSAMPLE 2
51 #define PPM_MAXVAL ((1<<BITS_IN_JSAMPLE)-1)
52 #endif
53 #endif
54
55
56 /*
57 * When JSAMPLE is the same size as char, we can just fwrite() the
58 * decompressed data to the PPM or PGM file. On PCs, in order to make this
59 * work the output buffer must be allocated in near data space, because we are
60 * assuming small-data memory model wherein fwrite() can't reach far memory.
61 * If you need to process very wide images on a PC, you might have to compile
62 * in large-memory model, or else replace fwrite() with a putc() loop ---
63 * which will be much slower.
64 */
65
66
67 /* Private version of data destination object */
68
69 typedef struct {
70 struct djpeg_dest_struct pub; /* public fields */
71
72 /* Usually these two pointers point to the same place: */
73 char *iobuffer; /* fwrite's I/O buffer */
74 JSAMPROW pixrow; /* decompressor output buffer */
75 size_t buffer_width; /* width of I/O buffer */
76 JDIMENSION samples_per_row; /* JSAMPLEs per output row */
77 } ppm_dest_struct;
78
79 typedef ppm_dest_struct * ppm_dest_ptr;
80
81
82 /*
83 * Write some pixel data.
84 * In this module rows_supplied will always be 1.
85 *
86 * put_pixel_rows handles the "normal" 8-bit case where the decompressor
87 * output buffer is physically the same as the fwrite buffer.
88 */
89
90 METHODDEF(void)
91 put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
92 JDIMENSION rows_supplied)
93 {
94 ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
95
96 (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
97 }
98
99
100 /*
101 * This code is used when we have to copy the data and apply a pixel
102 * format translation. Typically this only happens in 12-bit mode.
103 */
104
105 METHODDEF(void)
106 copy_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
107 JDIMENSION rows_supplied)
108 {
109 ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
110 register char * bufferptr;
111 register JSAMPROW ptr;
112 register JDIMENSION col;
113
114 ptr = dest->pixrow;
115 bufferptr = dest->iobuffer;
116 for (col = dest->samples_per_row; col > 0; col--) {
117 PUTPPMSAMPLE(bufferptr, GETJSAMPLE(*ptr++));
118 }
119 (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
120 }
121
122
123 /*
124 * Write some pixel data when color quantization is in effect.
125 * We have to demap the color index values to straight data.
126 */
127
128 METHODDEF(void)
129 put_demapped_rgb (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
130 JDIMENSION rows_supplied)
131 {
132 ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
133 register char * bufferptr;
134 register int pixval;
135 register JSAMPROW ptr;
136 register JSAMPROW color_map0 = cinfo->colormap[0];
137 register JSAMPROW color_map1 = cinfo->colormap[1];
138 register JSAMPROW color_map2 = cinfo->colormap[2];
139 register JDIMENSION col;
140
141 ptr = dest->pixrow;
142 bufferptr = dest->iobuffer;
143 for (col = cinfo->output_width; col > 0; col--) {
144 pixval = GETJSAMPLE(*ptr++);
145 PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map0[pixval]));
146 PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map1[pixval]));
147 PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map2[pixval]));
148 }
149 (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
150 }
151
152 METHODDEF(void)
153 put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
154 JDIMENSION rows_supplied)
155 {
156 ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
157 register char * bufferptr;
158 register JSAMPROW ptr;
159 register JSAMPROW color_map0 = cinfo->colormap[0];
160 register JDIMENSION col;
161
162 ptr = dest->pixrow;
163 bufferptr = dest->iobuffer;
164 for (col = cinfo->output_width; col > 0; col--) {
165 PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map0[GETJSAMPLE(*ptr++)]));
166 }
167 (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
168 }
169
170
171 /*
172 * Startup: write the file header.
173 */
174
175 METHODDEF(void)
176 start_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
177 {
178 /* Emit file header */
179 switch (cinfo->out_color_space) {
180 case JCS_GRAYSCALE:
181 /* emit header for raw PGM format */
182 fprintf(dinfo->output_file, "P5\n%ld %ld\n%d\n",
183 (long) cinfo->output_width, (long) cinfo->output_height,
184 PPM_MAXVAL);
185 break;
186 case JCS_RGB:
187 /* emit header for raw PPM format */
188 fprintf(dinfo->output_file, "P6\n%ld %ld\n%d\n",
189 (long) cinfo->output_width, (long) cinfo->output_height,
190 PPM_MAXVAL);
191 break;
192 default:
193 ERREXIT(cinfo, JERR_PPM_COLORSPACE);
194 }
195 }
196
197
198 /*
199 * Finish up at the end of the file.
200 */
201
202 METHODDEF(void)
203 finish_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
204 {
205 /* Make sure we wrote the output file OK */
206 JFFLUSH(dinfo->output_file);
207 if (JFERROR(dinfo->output_file))
208 ERREXIT(cinfo, JERR_FILE_WRITE);
209 }
210
211
212 /*
213 * The module selection routine for PPM format output.
214 */
215
216 GLOBAL(djpeg_dest_ptr)
217 jinit_write_ppm (j_decompress_ptr cinfo)
218 {
219 ppm_dest_ptr dest;
220
221 /* Create module interface object, fill in method pointers */
222 dest = (ppm_dest_ptr) (*cinfo->mem->alloc_small)
223 ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(ppm_dest_struct));
224 dest->pub.start_output = start_output_ppm;
225 dest->pub.finish_output = finish_output_ppm;
226
227 /* Calculate output image dimensions so we can allocate space */
228 jpeg_calc_output_dimensions(cinfo);
229
230 /* Create physical I/O buffer. Note we make this near on a PC. */
231 dest->samples_per_row = cinfo->output_width * cinfo->out_color_components;
232 dest->buffer_width = dest->samples_per_row * (BYTESPERSAMPLE * SIZEOF(char));
233 dest->iobuffer = (char *) (*cinfo->mem->alloc_small)
234 ((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width);
235
236 if (cinfo->quantize_colors || BITS_IN_JSAMPLE != 8 ||
237 SIZEOF(JSAMPLE) != SIZEOF(char)) {
238 /* When quantizing, we need an output buffer for colormap indexes
239 * that's separate from the physical I/O buffer. We also need a
240 * separate buffer if pixel format translation must take place.
241 */
242 dest->pixrow = (JSAMPROW) (*cinfo->mem->alloc_large)
243 ((j_common_ptr) cinfo, JPOOL_IMAGE, (size_t) cinfo->output_width *
244 (size_t) cinfo->output_components * SIZEOF(JSAMPLE));
245 if (! cinfo->quantize_colors)
246 dest->pub.put_pixel_rows = copy_pixel_rows;
247 else if (cinfo->out_color_space == JCS_GRAYSCALE)
248 dest->pub.put_pixel_rows = put_demapped_gray;
249 else
250 dest->pub.put_pixel_rows = put_demapped_rgb;
251 } else {
252 /* We will fwrite() directly from decompressor output buffer. */
253 /* Cast here implies near->far pointer conversion on PCs */
254 dest->pixrow = (JSAMPROW) dest->iobuffer;
255 dest->pub.put_pixel_rows = put_pixel_rows;
256 }
257 /* Synthesize a JSAMPARRAY pointer structure */
258 dest->pub.buffer = & dest->pixrow;
259 dest->pub.buffer_height = 1;
260
261 return &dest->pub;
262 }
263
264 #endif /* PPM_SUPPORTED */