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comparison jpg.c @ 2:bac8ed8d6eb9

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add jpeg coding and test stuff
author Peter Meerwald <pmeerw@pmeerw.net>
date Sun, 08 May 2011 18:22:22 +0200
parents
children e8957085fe8a
comparison
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1:111d4bbce605 2:bac8ed8d6eb9
1 #include <stdlib.h>
2 #include <stdio.h>
3 #include <string.h>
4 #include "jpeglib.h"
5 #include "jerror.h"
6
7 typedef struct {
8 struct jpeg_destination_mgr pub; /* public fields */
9
10 unsigned char ** outbuffer; /* target buffer */
11 unsigned long * outsize;
12 unsigned char * newbuffer; /* newly allocated buffer */
13 JOCTET * buffer; /* start of buffer */
14 size_t bufsize;
15 } mem_dest_mgr;
16
17 typedef mem_dest_mgr * mem_dest_mgr_ptr;
18
19 void init_mem_destination (j_compress_ptr cinfo) {
20 }
21
22 boolean empty_mem_output_buffer(j_compress_ptr cinfo) {
23 size_t nextsize;
24 JOCTET * nextbuffer;
25 mem_dest_mgr_ptr dest = (mem_dest_mgr_ptr) cinfo->dest;
26
27 /* Try to allocate new buffer with double size */
28 nextsize = dest->bufsize * 2;
29 nextbuffer = malloc(nextsize);
30
31 if (nextbuffer == NULL)
32 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
33
34 memcpy(nextbuffer, dest->buffer, dest->bufsize);
35
36 if (dest->newbuffer != NULL)
37 free(dest->newbuffer);
38
39 dest->newbuffer = nextbuffer;
40
41 dest->pub.next_output_byte = nextbuffer + dest->bufsize;
42 dest->pub.free_in_buffer = dest->bufsize;
43
44 dest->buffer = nextbuffer;
45 dest->bufsize = nextsize;
46
47 return TRUE;
48 }
49
50 void term_mem_destination(j_compress_ptr cinfo) {
51 mem_dest_mgr_ptr dest = (mem_dest_mgr_ptr) cinfo->dest;
52
53 *dest->outbuffer = dest->buffer;
54 *dest->outsize = dest->bufsize - dest->pub.free_in_buffer;
55 }
56
57 void jpeg_mem_dest(j_compress_ptr cinfo, unsigned char ** outbuffer, unsigned long * outsize) {
58 mem_dest_mgr_ptr dest;
59
60 if (outbuffer == NULL || outsize == NULL) /* sanity check */
61 ERREXIT(cinfo, JERR_BUFFER_SIZE);
62
63 /* The destination object is made permanent so that multiple JPEG images
64 * can be written to the same buffer without re-executing jpeg_mem_dest.
65 */
66 if (cinfo->dest == NULL) { /* first time for this JPEG object? */
67 cinfo->dest = (struct jpeg_destination_mgr *)
68 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
69 sizeof(mem_dest_mgr));
70 }
71
72 dest = (mem_dest_mgr_ptr) cinfo->dest;
73 dest->pub.init_destination = init_mem_destination;
74 dest->pub.empty_output_buffer = empty_mem_output_buffer;
75 dest->pub.term_destination = term_mem_destination;
76 dest->outbuffer = outbuffer;
77 dest->outsize = outsize;
78 dest->newbuffer = NULL;
79
80 if (*outbuffer == NULL || *outsize == 0) {
81 /* Allocate initial buffer */
82 dest->newbuffer = *outbuffer = malloc(65536);
83 if (dest->newbuffer == NULL)
84 ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
85 *outsize = 65536;
86 }
87
88 dest->pub.next_output_byte = dest->buffer = *outbuffer;
89 dest->pub.free_in_buffer = dest->bufsize = *outsize;
90 }
91
92
93 int build_jpg(JSAMPLE *image_buf, int width, int height) {
94 int scanline;
95 struct jpeg_compress_struct cinfo;
96 struct jpeg_error_mgr jerr;
97
98 cinfo.err = jpeg_std_error(&jerr);
99 jpeg_create_compress(&cinfo);
100
101 unsigned long out_size = 1<<20;
102 unsigned char *out_buf = NULL;
103 jpeg_mem_dest(&cinfo, &out_buf, &out_size);
104
105 cinfo.image_width = width;
106 cinfo.image_height = height;
107 cinfo.input_components = 3;
108 cinfo.in_color_space = JCS_RGB;
109 jpeg_set_defaults(&cinfo);
110
111 jpeg_start_compress(&cinfo, TRUE);
112
113 for (scanline = 0; scanline < height; scanline++) {
114 JSAMPROW *row_ptr;
115 row_ptr = &image_buf[scanline * width];
116 jpeg_write_scanlines(&cinfo, row_ptr, 1);
117 }
118
119 jpeg_finish_compress(&cinfo);
120
121 jpeg_destroy_compress(&cinfo);
122
123 return 0;
124 }

Repositories maintained by Peter Meerwald, pmeerw@pmeerw.net.