1 \/*
2 * jpegdump_main.cpp -- dump a JPEG stream
3 * by pts@math.bme.hu at Tue Jun 4 13:19:00 CEST 2002
4 */
5
6
7 /* Structure of a typical JPEG file:
8 (D8:SOI) (E0:APP0) (FE:COM)? (DB:DQT)*2 (C0:SOF0) (C4:DHT)*4 (DA:SOS)
9 ... (D9:EOI)
10 */
11
12 #ifdef __GNUC__
13 #ifndef __clang__
14 #pragma implementation
15 #endif
16 #endif
17
18 #include "config2.h"
19 #include <stdio.h>
20
21 #if OBJDEP
22 #warning PROVIDES: jpegdump_main
23 #endif
24
25 typedef slen_t dimen_t;
26 static const unsigned char
27 CS_UNKNOWN=0, /* error/unspecified */
28 CS_GRAYSCALE=1, /* monochrome */
29 CS_RGB=2, /* red/green/blue */
30 CS_YCbCr=3, /* Y/Cb/Cr (also known as YUV) */
31 CS_CMYK=4, /* C/M/Y/K */
32 CS_YCCK=5, /* Y/Cb/Cr/K */
33 CS_Indexed_RGB=12;
34
35
36 /* --- The following code is based on standard/image.c from PHP4 */
37
38 /* some defines for the different JPEG block types */
39 #define M_SOF0 0xC0 /* Start Of Frame N */
40 #define M_SOF1 0xC1 /* N indicates which compression process */
41 #define M_SOF2 0xC2 /* Only SOF0-SOF2 are now in common use */
42 #define M_SOF3 0xC3
43 #define M_SOF5 0xC5 /* NB: codes C4 and CC are NOT SOF markers */
44 #define M_SOF6 0xC6
45 #define M_SOF7 0xC7
46 #define M_SOF9 0xC9
47 #define M_SOF10 0xCA
48 #define M_SOF11 0xCB
49 #define M_SOF13 0xCD
50 #define M_SOF14 0xCE
51 #define M_SOF15 0xCF
52 #define M_SOI 0xD8
53 #define M_EOI 0xD9 /* End Of Image (end of datastream) */
54 #define M_SOS 0xDA /* Start Of Scan (begins compressed data) */
55 #define M_COM 0xFE /* comment */
56 #define M_DQT 0xDB /* QuantTables */
57 #define M_DHT 0xC4 /* HuffTables */
58 #define M_APP0 0xe0
59 #define M_APP1 0xe1
60 #define M_APP2 0xe2
61 #define M_APP3 0xe3
62 #define M_APP4 0xe4
63 #define M_APP5 0xe5
64 #define M_APP6 0xe6
65 #define M_APP7 0xe7
66 #define M_APP8 0xe8
67 #define M_APP9 0xe9
68 #define M_APP10 0xea
69 #define M_APP11 0xeb
70 #define M_APP12 0xec
71 #define M_APP13 0xed
72 #define M_APP14 0xee
73 #define M_APP15 0xef
74
75
jai_read2(FILE * fp)76 static unsigned short jai_read2(FILE *fp) {
77 unsigned char a[ 2 ];
78
79 /* just return 0 if we hit the end-of-file */
80 if (fread(a,sizeof(a),1,fp) != 1) return 0;
81
82 return (((unsigned short) a[ 0 ]) << 8) + ((unsigned short) a[ 1 ]);
83 }
84
jai_next_marker(FILE * fp)85 static unsigned int jai_next_marker(FILE *fp)
86 /* get next marker byte from file */
87 {
88 int c;
89
90 /* skip unimportant stuff */
91
92 c = MACRO_GETC(fp);
93
94 while (c != 0xff) {
95 if ((c = MACRO_GETC(fp)) == EOF)
96 return M_EOI; /* we hit EOF */
97 }
98
99 /* get marker byte, swallowing possible padding */
100 do {
101 if ((c = MACRO_GETC(fp)) == EOF)
102 return M_EOI; /* we hit EOF */
103 } while (c == 0xff);
104
105 // printf("marker=%02X\n", c);
106 return (unsigned int) c;
107 }
108
jai_skip_variable(FILE * fp)109 static void jai_skip_variable(FILE *fp)
110 /* skip over a variable-length block; assumes proper length marker */
111 {
112 unsigned short length;
113
114 printf("%lu: skip variable\n", ftell(fp));
115
116 length = jai_read2(fp);
117 length -= 2; /* length includes itself */
118 if (length>0) {
119 printf("... variable length=%u\n", length);
120 #if 0
121 fseek(fp, (long) length, SEEK_CUR); /* skip the header */
122 #endif
123 while (length--!=0) MACRO_GETC(fp); /* make feof(fp) correct */
124 printf("%lu: skipped variable; feof=%u\n", ftell(fp), feof(fp));
125 }
126 }
127
128 struct gfxinfo {
129 unsigned char bad, bpc, cpp, had_jfif, colortransform, id_rgb;
130 dimen_t height, width;
131 /** Offset of byte just _after_ the first SOF marker (FF C0 or alike)
132 * from the beginning of the file.
133 */
134 slen_t SOF_offs;
135 };
136
137 /** main loop to parse JPEG structure */
jai_handle_jpeg(struct gfxinfo * result,FILE * fp)138 static void jai_handle_jpeg(struct gfxinfo *result, FILE *fp) {
139 unsigned int length, marker;
140 unsigned char had_adobe, id, hvs, qtn;
141
142 result->bad=1; /* signal invalid return value */
143 result->id_rgb=0;
144 result->had_jfif=0;
145 result->colortransform=127; /* no Adobe marker yet */
146 // fseek(fp, 0L, SEEK_SET); /* position file pointer on SOF */
147
148 if (MACRO_GETC(fp) != 0xFF || MACRO_GETC(fp)!=M_SOI) return; /* JPEG header... */
149 printf("2: marker D8 (SOI)\n");
150
151 for (;;) {
152 assert(!feof(fp));
153 printf("... %lu\n", ftell(fp));
154 marker=jai_next_marker(fp);
155 printf("%lu: marker %02X\n", ftell(fp), marker);
156 switch (marker) {
157 case M_SOF0:
158 if (result->bad!=1) { result->bad=4; return; } /* only one M_SOF allowed */
159 result->SOF_offs=ftell(fp);
160 /* handle SOFn block */
161 length=jai_read2(fp);
162 result->bpc = MACRO_GETC(fp);
163 result->height = jai_read2(fp);
164 result->width = jai_read2(fp);
165 result->cpp = MACRO_GETC(fp);
166 if ((length-=8)!=3U*result->cpp) return;
167 if (result->cpp==3) {
168 result->id_rgb =(id=MACRO_GETC(fp)=='R'); hvs=MACRO_GETC(fp); qtn=MACRO_GETC(fp);
169 printf("Comp#1 id=0x%02X h_samp_fact=%u v_samp_fact=%u quant_tbl_no=%u\n",
170 id, hvs>>4, hvs&15, qtn);
171 result->id_rgb&=(id=MACRO_GETC(fp)=='G'); hvs=MACRO_GETC(fp); qtn=MACRO_GETC(fp);
172 printf("Comp#2 id=0x%02X h_samp_fact=%u v_samp_fact=%u quant_tbl_no=%u\n",
173 id, hvs>>4, hvs&15, qtn);
174 result->id_rgb&=(id=MACRO_GETC(fp)=='B'); hvs=MACRO_GETC(fp); qtn=MACRO_GETC(fp);
175 printf("Comp#3 id=0x%02X h_samp_fact=%u v_samp_fact=%u quant_tbl_no=%u\n",
176 id, hvs>>4, hvs&15, qtn);
177 } else while (length--!=0) MACRO_GETC(fp);
178 if (result->cpp!=1 && result->cpp!=3 && result->cpp!=4) {
179 result->bad=5; return;
180 }
181 if (feof(fp)) { result->bad=8; return; }
182 result->bad=2;
183 break;
184 case M_SOF1:
185 case M_SOF2:
186 case M_SOF3:
187 case M_SOF5:
188 case M_SOF6:
189 case M_SOF7:
190 case M_SOF9:
191 case M_SOF10:
192 case M_SOF11:
193 case M_SOF13:
194 case M_SOF14:
195 case M_SOF15:
196 // fprintf(stderr, "SOF%u\n", marker-M_SOF0); assert(0);
197 result->bad=3;
198 return;
199 case M_SOS: /* we are about to hit image data. We're done. */
200 jai_skip_variable(fp); /* anything else isn't interesting */
201 if (feof(fp)) { result->bad=8; return; }
202 if (result->bad==2 && !feof(fp)) result->bad=0;
203 /* Dat: we should really return() here, because the SOS marker is
204 * followed by binary data, not surrounded by markers.
205 */
206 break;
207 case M_EOI: /* end of image or EOF */
208 if (feof(fp)) result->bad=6;
209 else if (MACRO_GETC(fp)!=EOF) result->bad=7;
210 return;
211 case M_APP0: /* JFIF application-specific marker */
212 length=jai_read2(fp);
213 if (length==2+4+1+2+1+2+2+1+1) {
214 result->had_jfif=MACRO_GETC(fp)=='J' && MACRO_GETC(fp)=='F' && MACRO_GETC(fp)=='I' &&
215 MACRO_GETC(fp)=='F' && MACRO_GETC(fp)==0;
216 length-=7;
217 } else length-=2;
218 while (length--!=0) MACRO_GETC(fp);
219 if (feof(fp)) { result->bad=8; return; }
220 break;
221 case M_APP14: /* Adobe application-specific marker */
222 length=jai_read2(fp);
223 if ((length-=2)==5+2+2+2+1) {
224 had_adobe=MACRO_GETC(fp)=='A' && MACRO_GETC(fp)=='d' && MACRO_GETC(fp)=='o' &&
225 MACRO_GETC(fp)=='b' && MACRO_GETC(fp)=='e' && ((unsigned char)MACRO_GETC(fp))>=1;
226 MACRO_GETC(fp); MACRO_GETC(fp); MACRO_GETC(fp); MACRO_GETC(fp); MACRO_GETC(fp);
227 if (had_adobe) result->colortransform=MACRO_GETC(fp);
228 else MACRO_GETC(fp);
229 } else while (length--!=0) MACRO_GETC(fp);
230 if (feof(fp)) { result->bad=8; return; }
231 break;
232 case M_APP1:
233 case M_APP2:
234 case M_APP3:
235 case M_APP4:
236 case M_APP5:
237 case M_APP6:
238 case M_APP7:
239 case M_APP8:
240 case M_APP9:
241 case M_APP10:
242 case M_APP11:
243 case M_APP12:
244 case M_APP13:
245 case M_APP15:
246 /* fall through */
247 default:
248 jai_skip_variable(fp); /* anything else isn't interesting */
249 if (feof(fp)) { result->bad=8; return; }
250 break;
251 } }
252 }
253
254 static char *jai_errors[]={
255 (char*)NULLP,
256 /*1*/ "missing SOF0 marker",
257 /*2*/ "EOF|EOI before SOS", /* "premature EOF", */
258 /*3*/ "not a Baseline JPEG (SOF must be SOF0)",
259 /*4*/ "more SOF0 markers",
260 /*5*/ "bad # components",
261 /*6*/ "EOF before EOI",
262 /*7*/ "extra bytes after EOI",
263 /*8*/ "EOF before end of parametric marker",
264 };
265
main(int argc,char ** argv)266 int main(int argc, char **argv) {
267 struct gfxinfo gi;
268 FILE *f=argc>=2 ? fopen(argv[1], "rb"): stdin;
269 jai_handle_jpeg(&gi, f);
270 if (gi.bad==1) {
271 printf("JAI: Warning: %s.\n", jai_errors[gi.bad]);
272 gi.cpp=1;
273 gi.width=0;
274 gi.height=0;
275 gi.SOF_offs=0;
276 gi.bpc=0;
277 } else if (gi.bad!=0) { printf("JAI: %s.\n", jai_errors[gi.bad]); if (gi.bad!=1) return 1; }
278 unsigned char colorspace;
279 if (gi.cpp==1) {
280 colorspace=CS_GRAYSCALE;
281 } else if (gi.cpp==3) {
282 colorspace=CS_YCbCr;
283 if (gi.had_jfif!=0) ;
284 else if (gi.colortransform==0) colorspace=CS_RGB;
285 else if (gi.colortransform==1) ;
286 else if (gi.colortransform!=127) { printf("JAI: unknown ColorTransform: %u\n", (unsigned)gi.colortransform); return 2; }
287 else if (gi.id_rgb!=0) colorspace=CS_RGB;
288 /* Imp: check for id_ycbcr */
289 else printf("JAI: assuming YCbCr color space\n");
290 } else if (gi.cpp==4) {
291 colorspace=CS_CMYK;
292 if (gi.colortransform==0) ;
293 else if (gi.colortransform==2) colorspace=CS_YCCK;
294 else if (gi.colortransform!=127) { printf("JAI: unknown ColorTransform: %u\n", (unsigned)gi.colortransform); return 2; }
295 } else assert(0);
296 fseek(f, 0L, 2); /* EOF */
297 long flen=ftell(f); /* skip extra bytes after EOI */
298 fclose(f);
299 printf("%lu: flen\n", flen);
300 printf("bpc=%u cpp=%u had_jfif=%u colortransform=%u id_rgb=%u colorspace=%u\n",
301 gi.bpc, gi.cpp, gi.had_jfif, gi.colortransform, gi.id_rgb, colorspace);
302 printf("wd=%u ht=%u SOF_offs=%u\n", gi.width, gi.height, gi.SOF_offs);
303 return 0;
304 }
305
306 /* __EOF__ */
307