dll/3rdparty/libjpeg/jpegexiforient.c

   1 /*
   2  * jpegexiforient.c
   3  *
   4  * This is a utility program to get and set the Exif Orientation Tag.
   5  * It can be used together with jpegtran in scripts for automatic
   6  * orientation correction of digital camera pictures.
   7  *
   8  * The Exif orientation value gives the orientation of the camera
   9  * relative to the scene when the image was captured.  The relation
  10  * of the '0th row' and '0th column' to visual position is shown as
  11  * below.
  12  *
  13  * Value | 0th Row     | 0th Column
  14  * ------+-------------+-----------
  15  *   1   | top         | left side
  16  *   2   | top         | rigth side
  17  *   3   | bottom      | rigth side
  18  *   4   | bottom      | left side
  19  *   5   | left side   | top
  20  *   6   | right side  | top
  21  *   7   | right side  | bottom
  22  *   8   | left side   | bottom
  23  *
  24  * For convenience, here is what the letter F would look like if it were
  25  * tagged correctly and displayed by a program that ignores the orientation
  26  * tag:
  27  *
  28  *   1        2       3      4         5            6           7          8
  29  *
  30  * 888888  888888      88  88      8888888888  88                  88  8888888888
  31  * 88          88      88  88      88  88      88  88          88  88      88  88
  32  * 8888      8888    8888  8888    88          8888888888  8888888888          88
  33  * 88          88      88  88
  34  * 88          88  888888  888888
  35  *
  36  */
  37
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40
  41 static FILE * myfile;           /* My JPEG file */
  42
  43 static unsigned char exif_data[65536L];
  44
  45 /* Return next input byte, or EOF if no more */
  46 #define NEXTBYTE()  getc(myfile)
  47
  48 /* Error exit handler */
  49 #define ERREXIT(msg)  (exit(0))
  50
  51 /* Read one byte, testing for EOF */
  52 static int
  53 read_1_byte (void)
  54 {
  55   int c;
  56
  57   c = NEXTBYTE();
  58   if (c == EOF)
  59     ERREXIT("Premature EOF in JPEG file");
  60   return c;
  61 }
  62
  63 /* Read 2 bytes, convert to unsigned int */
  64 /* All 2-byte quantities in JPEG markers are MSB first */
  65 static unsigned int
  66 read_2_bytes (void)
  67 {
  68   int c1, c2;
  69
  70   c1 = NEXTBYTE();
  71   if (c1 == EOF)
  72     ERREXIT("Premature EOF in JPEG file");
  73   c2 = NEXTBYTE();
  74   if (c2 == EOF)
  75     ERREXIT("Premature EOF in JPEG file");
  76   return (((unsigned int) c1) << 8) + ((unsigned int) c2);
  77 }
  78
  79 static const char * progname;   /* program name for error messages */
  80
  81 static void
  82 usage (FILE *out)
  83 /* complain about bad command line */
  84 {
  85   fprintf(out, "jpegexiforient reads or writes the Exif Orientation Tag ");
  86   fprintf(out, "in a JPEG Exif file.\n");
  87
  88   fprintf(out, "Usage: %s [switches] jpegfile\n", progname);
  89
  90   fprintf(out, "Switches:\n");
  91   fprintf(out, "  --help     display this help and exit\n");
  92   fprintf(out, "  --version  output version information and exit\n");
  93   fprintf(out, "  -n         Do not output the trailing newline\n");
  94   fprintf(out, "  -1 .. -8   Set orientation value 1 .. 8\n");
  95 }
  96
  97 /*
  98  * The main program.
  99  */
 100
 101 int
 102 main (int argc, char **argv)
 103 {
 104   int n_flag, set_flag;
 105   unsigned int length, i;
 106   int is_motorola; /* Flag for byte order */
 107   unsigned int offset, number_of_tags, tagnum;
 108
 109   progname = argv[0];
 110   if (progname == NULL || progname[0] == 0)
 111     progname = "jpegexiforient";        /* in case C library doesn't provide it */
 112
 113   if (argc < 2) { usage(stderr); return 1; }
 114
 115   n_flag = 0; set_flag = 0;
 116
 117   i = 1;
 118   while (argv[i][0] == '-') {
 119     switch (argv[i][1]) {
 120     case '-':
 121       switch (argv[i][2]) {
 122         case 'h': usage(stdout); return 0;
 123         case 'v': fprintf(stdout,"jpegexiforient\n"); return 0;
 124         }
 125     case 'n':
 126       n_flag = 1;
 127       break;
 128     case '1':
 129     case '2':
 130     case '3':
 131     case '4':
 132     case '5':
 133     case '6':
 134     case '7':
 135     case '8':
 136       set_flag = argv[i][1] - '0';
 137       break;
 138     default:
 139       usage(stderr); return 1;
 140     }
 141     if (++i >= argc) { usage(stderr); return 1; }
 142   }
 143
 144   if (set_flag) {
 145     if ((myfile = fopen(argv[i], "rb+")) == NULL) {
 146       fprintf(stderr, "%s: can't open %s\n", progname, argv[i]);
 147       return 0;
 148     }
 149   } else {
 150     if ((myfile = fopen(argv[i], "rb")) == NULL) {
 151       fprintf(stderr, "%s: can't open %s\n", progname, argv[i]);
 152       return 0;
 153     }
 154   }
 155
 156   /* Read File head, check for JPEG SOI + Exif APP1 */
 157   for (i = 0; i < 4; i++)
 158     exif_data[i] = (unsigned char) read_1_byte();
 159   if (exif_data[0] != 0xFF ||
 160       exif_data[1] != 0xD8 ||
 161       exif_data[2] != 0xFF ||
 162       exif_data[3] != 0xE1)
 163     return 0;
 164
 165   /* Get the marker parameter length count */
 166   length = read_2_bytes();
 167   /* Length includes itself, so must be at least 2 */
 168   /* Following Exif data length must be at least 6 */
 169   if (length < 8)
 170     return 0;
 171   length -= 8;
 172   /* Read Exif head, check for "Exif" */
 173   for (i = 0; i < 6; i++)
 174     exif_data[i] = (unsigned char) read_1_byte();
 175   if (exif_data[0] != 0x45 ||
 176       exif_data[1] != 0x78 ||
 177       exif_data[2] != 0x69 ||
 178       exif_data[3] != 0x66 ||
 179       exif_data[4] != 0 ||
 180       exif_data[5] != 0)
 181     return 0;
 182   /* Read Exif body */
 183   for (i = 0; i < length; i++)
 184     exif_data[i] = (unsigned char) read_1_byte();
 185
 186   if (length < 12) return 0; /* Length of an IFD entry */
 187
 188   /* Discover byte order */
 189   if (exif_data[0] == 0x49 && exif_data[1] == 0x49)
 190     is_motorola = 0;
 191   else if (exif_data[0] == 0x4D && exif_data[1] == 0x4D)
 192     is_motorola = 1;
 193   else
 194     return 0;
 195
 196   /* Check Tag Mark */
 197   if (is_motorola) {
 198     if (exif_data[2] != 0) return 0;
 199     if (exif_data[3] != 0x2A) return 0;
 200   } else {
 201     if (exif_data[3] != 0) return 0;
 202     if (exif_data[2] != 0x2A) return 0;
 203   }
 204
 205   /* Get first IFD offset (offset to IFD0) */
 206   if (is_motorola) {
 207     if (exif_data[4] != 0) return 0;
 208     if (exif_data[5] != 0) return 0;
 209     offset = exif_data[6];
 210     offset <<= 8;
 211     offset += exif_data[7];
 212   } else {
 213     if (exif_data[7] != 0) return 0;
 214     if (exif_data[6] != 0) return 0;
 215     offset = exif_data[5];
 216     offset <<= 8;
 217     offset += exif_data[4];
 218   }
 219   if (offset > length - 2) return 0; /* check end of data segment */
 220
 221   /* Get the number of directory entries contained in this IFD */
 222   if (is_motorola) {
 223     number_of_tags = exif_data[offset];
 224     number_of_tags <<= 8;
 225     number_of_tags += exif_data[offset+1];
 226   } else {
 227     number_of_tags = exif_data[offset+1];
 228     number_of_tags <<= 8;
 229     number_of_tags += exif_data[offset];
 230   }
 231   if (number_of_tags == 0) return 0;
 232   offset += 2;
 233
 234   /* Search for Orientation Tag in IFD0 */
 235   for (;;) {
 236     if (offset > length - 12) return 0; /* check end of data segment */
 237     /* Get Tag number */
 238     if (is_motorola) {
 239       tagnum = exif_data[offset];
 240       tagnum <<= 8;
 241       tagnum += exif_data[offset+1];
 242     } else {
 243       tagnum = exif_data[offset+1];
 244       tagnum <<= 8;
 245       tagnum += exif_data[offset];
 246     }
 247     if (tagnum == 0x0112) break; /* found Orientation Tag */
 248     if (--number_of_tags == 0) return 0;
 249     offset += 12;
 250   }
 251
 252   if (set_flag) {
 253     /* Set the Orientation value */
 254     if (is_motorola) {
 255       exif_data[offset+2] = 0; /* Format = unsigned short (2 octets) */
 256       exif_data[offset+3] = 3;
 257       exif_data[offset+4] = 0; /* Number Of Components = 1 */
 258       exif_data[offset+5] = 0;
 259       exif_data[offset+6] = 0;
 260       exif_data[offset+7] = 1;
 261       exif_data[offset+8] = 0;
 262       exif_data[offset+9] = (unsigned char)set_flag;
 263       exif_data[offset+10] = 0;
 264       exif_data[offset+11] = 0;
 265     } else {
 266       exif_data[offset+2] = 3; /* Format = unsigned short (2 octets) */
 267       exif_data[offset+3] = 0;
 268       exif_data[offset+4] = 1; /* Number Of Components = 1 */
 269       exif_data[offset+5] = 0;
 270       exif_data[offset+6] = 0;
 271       exif_data[offset+7] = 0;
 272       exif_data[offset+8] = (unsigned char)set_flag;
 273       exif_data[offset+9] = 0;
 274       exif_data[offset+10] = 0;
 275       exif_data[offset+11] = 0;
 276     }
 277     fseek(myfile, (4 + 2 + 6 + 2) + offset, SEEK_SET);
 278     fwrite(exif_data + 2 + offset, 1, 10, myfile);
 279   } else {
 280     /* Get the Orientation value */
 281     if (is_motorola) {
 282       if (exif_data[offset+8] != 0) return 0;
 283       set_flag = exif_data[offset+9];
 284     } else {
 285       if (exif_data[offset+9] != 0) return 0;
 286       set_flag = exif_data[offset+8];
 287     }
 288     if (set_flag > 8) return 0;
 289   }
 290
 291   /* Write out Orientation value */
 292   if (n_flag)
 293     printf("%c", '0' + set_flag);
 294   else
 295     printf("%c\n", '0' + set_flag);
 296
 297   /* All done. */
 298   return 0;
 299 }