Why not?
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346
src/cmd/jpg/jpegdump.c
Normal file
346
src/cmd/jpg/jpegdump.c
Normal file
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/* jpeg parser by tom szymanski */
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <math.h>
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#include <ctype.h>
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/* subroutines done by macros */
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#define min(A,B) ((A)<(B) ? (A) : (B))
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#define max(A,B) ((A)>(B) ? (A) : (B))
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#define maxeql(A,B) if (A < (B)) A = (B);
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#define mineql(A,B) if (A > (B)) A = (B);
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#define eatarg0 (argc--, argv++)
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#define arrayLength(A) ((sizeof A)/ (sizeof A[0]))
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FILE *infile;
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char *fname;
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/* Routines to print error messages of varying severity */
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/* externally visible variables */
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int warncnt;
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char *myname;
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void getname (char *arg) {
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/* Save name of invoking program for use by error routines */
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register char *p;
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p = strrchr (arg, '/');
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if (p == NULL)
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myname = arg;
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else
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myname = ++p;
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}
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static void introduction (void) {
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warncnt++;
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fflush (stdout);
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if (myname != NULL)
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fprintf (stderr, "%s: ", myname);
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}
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void warn (char *fmt, ...) {
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va_list args;
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introduction ();
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va_start (args, fmt);
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vfprintf (stderr, fmt, args);
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va_end (args);
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fputc ('\n', stderr);
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fflush (stderr);
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}
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void quit (char *fmt, ...) {
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va_list args;
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introduction ();
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va_start (args, fmt);
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vfprintf (stderr, fmt, args);
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va_end (args);
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fputc ('\n', stderr);
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fflush (stderr);
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exit (1);
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}
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void fatal (char *fmt, ...) {
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va_list args;
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introduction ();
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va_start (args, fmt);
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vfprintf (stderr, fmt, args);
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va_end (args);
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fprintf (stderr, "\nbetter get help!\n");
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fflush (stderr);
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abort ();
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}
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int toption = 0;
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int dqt[16][64];
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int get1 (void) {
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unsigned char x;
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if (fread(&x, 1, 1, infile) == 0)
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quit ("unexpected EOF");
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return x;
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}
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int get2 (void) {
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int x;
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x = get1() << 8;
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return x | get1();
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}
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void eatmarker (int kind) {
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int l, c;
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l = get2();
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printf ("%02x len=%d\n", kind, l);
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for (l -= 2; l > 0; l--)
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get1();
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}
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char *sofName[16] = {
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"Baseline sequential DCT - Huffman coding",
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"Extended sequential DCT - Huffman coding",
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"Progressive DCT - Huffman coding",
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"Lossless - Huffman coding",
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"4 is otherwise used",
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"Sequential DCT - differential Huffman coding",
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"Progressive DCT - differential Huffman coding",
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"Lossless - differential Huffman coding",
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"8 is reserved",
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"Extended Sequential DCT - arithmetic coding",
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"Progressive DCT - arithmetic coding",
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"Lossless - arithmetic coding",
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"c is otherwise used",
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"Sequential DCT - differential arithmetic coding",
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"Progressive DCT - differential arithmetic coding",
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"Lossless - differential arithmetic coding",
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};
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void get_sof (int kind) {
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int i, length, height, width, precision, ncomponents;
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int id, sf, tab;
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length = get2();
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precision = get1();
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height = get2();
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width = get2();
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ncomponents = get1();
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printf ("SOF%d:\t%s\n", kind - 0xc0, sofName[kind - 0xc0]);
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printf ("\t%d wide, %d high, %d deep, %d components\n",
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width, height, precision, ncomponents);
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for (i = 0; i < ncomponents; i++) {
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id = get1();
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sf = get1();
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tab = get1();
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printf ("\tcomponent %d: %d hsample, %d vsample, quantization table %d\n",
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id, sf >> 4, sf & 0xf, tab);
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}
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}
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void get_com (int kind) {
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int l, c;
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l = get2();
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printf ("COM len=%d '", l);
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for (l -= 2; l > 0; l--)
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putchar (c = get1());
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printf ("'\n");
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}
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void get_app (int kind) {
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int l, c, first;
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char buf[6];
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int nbuf, nok;
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l = get2();
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printf ("APP%d len=%d\n", kind - 0xe0, l);
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nbuf = 0;
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nok = 0;
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first = 1;
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/* dump printable strings in comment */
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for (l -= 2; l > 0; l--){
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c = get1();
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if(isprint(c)){
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if(nbuf >= sizeof buf){
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if(!first && nbuf == nok)
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printf(" ");
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printf("%.*s", nbuf, buf);
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nbuf = 0;
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first = 0;
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}
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buf[nbuf++] = c;
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nok++;
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}else{
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if(nok >= sizeof buf)
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if(nbuf > 0)
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printf("%.*s", nbuf, buf);
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nbuf = 0;
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nok = 0;
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}
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}
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if(nok >= sizeof buf)
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if(nbuf > 0){
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if(!first && nbuf == nok)
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printf(" ");
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printf("%.*s", nbuf, buf);
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}
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}
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void get_dac (int kind) {
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eatmarker (kind);
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}
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int get1dqt (void) {
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int t, p, i, *tab;
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t = get1();
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p = t >> 4;
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t = t & 0xf;
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printf ("DQT:\tp = %d, table = %d\n", p, t);
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tab = &dqt[t][0];
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for (i = 0; i < 64; i++)
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tab[i] = p ? get2() : get1();
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if (toption) {
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for (i = 0; i < 64; i++)
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printf ("\t%q[%02d] = %d\n", i, tab[i]);
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}
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return p ? 65 : 129;
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}
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void get_dqt (int kind) {
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int length;
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length = get2() - 2;
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while (length > 0)
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length -= get1dqt();
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}
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int get1dht (void) {
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int l, tcth, p, i, j, v[16], vv[16][256];
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tcth = get1();
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printf ("DHT:\tclass = %d, table = %d\n", tcth >> 4, tcth & 0xf);
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for (i = 0; i < 16; i++)
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v[i] = get1();
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l = 17;
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for (i = 0; i < 16; i++)
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for (j = 0; j < v[i]; j++) {
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vv[i][j] = get1();
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l += 1;
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}
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if (toption) {
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for (i = 0; i < 16; i++)
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printf ("\t%l[%02d] = %d\n", i+1, v[i]);
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for (i = 0; i < 16; i++)
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for (j = 0; j < v[i]; j++)
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printf ("\t%v[%02d,%02d] = %d\n", i+1, j+1, vv[i][j]);
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}
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return l;
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}
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void get_dht (int kind) {
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int length;
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length = get2() - 2;
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while (length > 0)
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length -= get1dht();
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}
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void get_sos (int kind) {
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int i, length, ncomponents, id, dcac, ahal;
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length = get2();
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ncomponents = get1();
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printf ("SOS:\t%d components\n", ncomponents);
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for (i = 0; i < ncomponents; i++) {
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id = get1();
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dcac = get1();
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printf ("\tcomponent %d: %d DC, %d AC\n", id, dcac >> 4, dcac & 0xf);
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}
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printf ("\tstart spectral %d\n", get1());
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printf ("\tend spectral %d\n", get1());
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ahal = get1();
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printf ("\tah = %d, al = %d\n", ahal >> 4, ahal &0xf);
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}
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main (int argc, char *argv[]) {
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int l, stuff, i, j, c;
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while (argc > 1 && argv[1][0] == '-') {
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switch (argv[1][1]) {
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case 't':
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toption = 1;
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break;
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default:
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warn ("bad option '%c'", argv[1][1]);
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}
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eatarg0;
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}
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fname = argv[1];
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infile = fopen (fname, "r");
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if (infile == NULL)
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quit ("can't open %s\n", fname);
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Start:
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// if (get1() != 0xff || get1() != 0xd8)
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// quit ("not JFIF");
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// printf ("SOI\n");
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// get_app (0xe0);
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for (;;) {
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c = get1();
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if (c != 0xff)
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quit ("expected marker, got %2x", c);
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do {
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c = get1();
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} while (c == 0xff);
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marker:
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switch (c) {
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case 0xc0: case 0xc1: case 0xc2: case 0xc3:
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case 0xc5: case 0xc6: case 0xc7:
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case 0xc8: case 0xc9: case 0xca: case 0xcb:
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case 0xcd: case 0xce: case 0xcf:
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get_sof (c);
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break;
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case 0xc4:
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get_dht (c);
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break;
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case 0xcc:
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get_dac (c);
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break;
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case 0xd8:
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printf ("SOI\n");
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break;
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case 0xe0: case 0xe1: case 0xe2: case 0xe3:
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case 0xe4: case 0xe5: case 0xe6: case 0xe7:
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case 0xe8: case 0xe9: case 0xea: case 0xeb:
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case 0xec: case 0xed: case 0xee: case 0xef:
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get_app(c);
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break;
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case 0xda:
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get_sos (c);
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goto newentropy;
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case 0xdb:
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get_dqt (c);
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break;
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case 0xfe:
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get_com (c);
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break;
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case 0xd9:
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printf ("EOI\n");
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if((c=getc(infile)) == EOF)
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exit(0);
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ungetc(c, infile);
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goto Start;
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default:
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eatmarker (c);
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}
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continue;
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newentropy:
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l = stuff = 0;
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entropy:
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while ((c = get1()) != 0xff)
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l += 1;
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while (c == 0xff)
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c = get1();
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if (c == 0) {
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stuff += 1;
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goto entropy;
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}
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printf ("sequence length %d with %d stuffs\n", l, stuff);
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if (0xd0 <= c && c <= 0xd7) {
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printf ("restart %d\n", c - 0xd0);
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goto newentropy;
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}
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goto marker;
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}
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}
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