src/cmd/jpg/jpegdump.c - plan9 - Git at Google

 /* jpeg parser by tom szymanski */
 #include <stddef.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <math.h>
 #include <ctype.h>

 /* subroutines done by macros */
 #define min(A,B)	((A)<(B) ? (A) : (B))
 #define max(A,B)	((A)>(B) ? (A) : (B))
 #define maxeql(A,B)	if (A < (B)) A = (B);
 #define mineql(A,B)	if (A > (B)) A = (B);
 #define eatarg0		(argc--, argv++)
 #define arrayLength(A) ((sizeof A)/ (sizeof A[0]))

 FILE *infile;
 char *fname;

 /* Routines to print error messages of varying severity */

 /* externally visible variables */
 int   warncnt;
 char *myname;

 void getname (char *arg) {
 	/* Save name of invoking program for use by error routines */
 	register char *p;
 	p = strrchr (arg, '/');
 	if (p == NULL)
 		myname = arg;
 	else
 		myname = ++p;
 }

 static void introduction (void) {
 	warncnt++;
 	fflush (stdout);
 	if (myname != NULL)
 		fprintf (stderr, "%s: ", myname);
 }

 void warn (char *fmt, ...) {
 	va_list args;
 	introduction ();
 	va_start (args, fmt);
 	vfprintf (stderr, fmt, args);
 	va_end (args);
 	fputc ('\n', stderr);
 	fflush (stderr);
 }

 void quit (char *fmt, ...) {
 	va_list args;
 	introduction ();
 	va_start (args, fmt);
 	vfprintf (stderr, fmt, args);
 	va_end (args);
 	fputc ('\n', stderr);
 	fflush (stderr);
 	exit (1);
 }

 void fatal (char *fmt, ...) {
 	va_list args;
 	introduction ();
 	va_start (args, fmt);
 	vfprintf (stderr, fmt, args);
 	va_end (args);
 	fprintf (stderr, "\nbetter get help!\n");
 	fflush (stderr);
 	abort ();
 }

 int toption = 0;
 int dqt[16][64];

 int get1 (void) {
 	unsigned char x;
 	if (fread(&x, 1, 1, infile) == 0)
 		quit ("unexpected EOF");
 	return x;
 }

 int get2 (void) {
 	int x;

 	x = get1() << 8;
 	return x | get1();
 }

 void eatmarker (int kind) {
 	int l, c;
 	l = get2();
 	printf ("%02x len=%d\n", kind, l);
 	for (l -= 2; l > 0; l--)
 		get1();
 }

 char *sofName[16] = {
 	"Baseline sequential DCT - Huffman coding",
 	"Extended sequential DCT - Huffman coding",
 	"Progressive DCT - Huffman coding",
 	"Lossless - Huffman coding",
 	"4 is otherwise used",
 	"Sequential DCT - differential Huffman coding",
 	"Progressive DCT - differential Huffman coding",
 	"Lossless - differential Huffman coding",
 	"8 is reserved",
 	"Extended Sequential DCT - arithmetic coding",
 	"Progressive DCT - arithmetic coding",
 	"Lossless - arithmetic coding",
 	"c is otherwise used",
 	"Sequential DCT - differential arithmetic coding",
 	"Progressive DCT - differential arithmetic coding",
 	"Lossless - differential arithmetic coding"
 };

 void get_sof (int kind) {
 	int i, length, height, width, precision, ncomponents;
 	int id, sf, tab;
 	length = get2();
 	precision = get1();
 	height = get2();
 	width = get2();
 	ncomponents = get1();
 	printf ("SOF%d:\t%s\n", kind - 0xc0, sofName[kind - 0xc0]);
 	printf ("\t%d wide, %d high, %d deep, %d components\n",
 		width, height, precision, ncomponents);
 	for (i = 0; i < ncomponents; i++) {
 		id = get1();
 		sf = get1();
 		tab = get1();
 		printf ("\tcomponent %d: %d hsample, %d vsample, quantization table %d\n",
 			id, sf >> 4, sf & 0xf, tab);
 	}
 }

 void get_com (int kind) {
 	int l, c;
 	l = get2();
 	printf ("COM len=%d '", l);
 	for (l -= 2; l > 0; l--)
 		putchar (c = get1());
 	printf ("'\n");
 }

 void get_app (int kind) {
 	int l, c, first;
 	char buf[6];
 	int nbuf, nok;
 	l = get2();
 	printf ("APP%d len=%d\n", kind - 0xe0, l);
 	nbuf = 0;
 	nok = 0;
 	first = 1;
 	/* dump printable strings in comment */
 	for (l -= 2; l > 0; l--){
 		c = get1();
 		if(isprint(c)){
 			if(nbuf >= sizeof buf){
 				if(!first && nbuf == nok)
 					printf(" ");
 				printf("%.*s", nbuf, buf);
 				nbuf = 0;
 				first = 0;
 			}
 			buf[nbuf++] = c;
 			nok++;
 		}else{
 			if(nok >= sizeof buf)
 				if(nbuf > 0)
 					printf("%.*s", nbuf, buf);
 			nbuf = 0;
 			nok = 0;
 		}
 	}
 	if(nok >= sizeof buf)
 		if(nbuf > 0){
 			if(!first && nbuf == nok)
 				printf(" ");
 			printf("%.*s", nbuf, buf);
 		}
 }

 void get_dac (int kind) {
 	eatmarker (kind);
 }

 int get1dqt (void) {
 	int t, p, i, *tab;
 	t = get1();
 	p = t >> 4;
 	t = t & 0xf;
 	printf ("DQT:\tp = %d, table = %d\n", p, t);
 	tab = &dqt[t][0];
 	for (i = 0; i < 64; i++)
 		tab[i] = p ? get2() : get1();
 	if (toption) {
 		for (i = 0; i < 64; i++)
 			printf ("\t%q[%02d] = %d\n", i, tab[i]);
 	}
 	return p ? 65 : 129;
 }

 void get_dqt (int kind) {
 	int length;
 	length = get2() - 2;
 	while (length > 0)
 		length -= get1dqt();
 }

 int get1dht (void) {
 	int l, tcth, p, i, j, v[16], vv[16][256];
 	tcth = get1();
 	printf ("DHT:\tclass = %d, table = %d\n", tcth >> 4, tcth & 0xf);
 	for (i = 0; i < 16; i++)
 		v[i] = get1();
 	l = 17;
 	for (i = 0; i < 16; i++)
 		for (j = 0; j < v[i]; j++) {
 			vv[i][j] = get1();
 			l += 1;
 		}
 	if (toption) {
 		for (i = 0; i < 16; i++)
 			printf ("\t%l[%02d] = %d\n", i+1, v[i]);
 		for (i = 0; i < 16; i++)
 			for (j = 0; j < v[i]; j++)
 				printf ("\t%v[%02d,%02d] = %d\n", i+1, j+1, vv[i][j]);
 	}
 	return l;
 }

 void get_dht (int kind) {
 	int length;
 	length = get2() - 2;
 	while (length > 0)
 		length -= get1dht();
 }

 void get_sos (int kind) {
 	int i, length, ncomponents, id, dcac, ahal;
 	length = get2();
 	ncomponents = get1();
 	printf ("SOS:\t%d components\n", ncomponents);
 	for (i = 0; i < ncomponents; i++) {
 		id = get1();
 		dcac = get1();
 		printf ("\tcomponent %d: %d DC, %d AC\n", id, dcac >> 4, dcac & 0xf);
 	}
 	printf ("\tstart spectral %d\n", get1());
 	printf ("\tend spectral %d\n", get1());
 	ahal = get1();
 	printf ("\tah = %d, al = %d\n", ahal >> 4, ahal &0xf);
 }

 main (int argc, char *argv[]) {
 	int l, stuff, i, j, c;
 	while (argc > 1 && argv[1][0] == '-') {
 		switch (argv[1][1]) {
 		case 't':
 			toption = 1;
 			break;
 		default:
 			warn ("bad option '%c'", argv[1][1]);
 		}
 		eatarg0;
 	}
 	fname = argv[1];
 	infile = fopen (fname, "r");
 	if (infile == NULL)
 		quit ("can't open %s\n", fname);
     Start:
 /*	if (get1() != 0xff || get1() != 0xd8) */
 /*		quit ("not JFIF"); */
 /*	printf ("SOI\n"); */
 /*	get_app (0xe0); */
 	for (;;) {
 		c = get1();
 		if (c != 0xff)
 			quit ("expected marker, got %2x", c);
 		do {
 			c = get1();
 		} while (c == 0xff);
 marker:
 		switch (c) {
 		case 0xc0: case 0xc1: case 0xc2: case 0xc3:
 		case 0xc5: case 0xc6: case 0xc7:
 		case 0xc8: case 0xc9: case 0xca: case 0xcb:
 		case 0xcd: case 0xce: case 0xcf:
 			get_sof (c);
 			break;
 		case 0xc4:
 			get_dht (c);
 			break;
 		case 0xcc:
 			get_dac (c);
 			break;
 		case 0xd8:
 			printf ("SOI\n");
 			break;
 		case 0xe0: case 0xe1: case 0xe2: case 0xe3:
 		case 0xe4: case 0xe5: case 0xe6: case 0xe7:
 		case 0xe8: case 0xe9: case 0xea: case 0xeb:
 		case 0xec: case 0xed: case 0xee: case 0xef:
 			get_app(c);
 			break;
 		case 0xda:
 			get_sos (c);
 			goto newentropy;
 		case 0xdb:
 			get_dqt (c);
 			break;
 		case 0xfe:
 			get_com (c);
 			break;
 		case 0xd9:
 			printf ("EOI\n");
 			if((c=getc(infile)) == EOF)
 				exit(0);
 			ungetc(c, infile);
 			goto Start;
 		default:
 			eatmarker (c);
 		}
 		continue;
 newentropy:
 		l = stuff = 0;
 entropy:
 		while ((c = get1()) != 0xff)
 			l += 1;
 		while (c == 0xff)
 			c = get1();
 		if (c == 0) {
 			stuff += 1;
 			goto entropy;
 		}
 		printf ("sequence length %d with %d stuffs\n", l, stuff);
 		if (0xd0 <= c && c <= 0xd7) {
 			printf ("restart %d\n", c - 0xd0);
 			goto newentropy;
 		}
 		goto marker;
 	}
 }
	/* jpeg parser by tom szymanski */
	#include <stddef.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>
	#include <math.h>
	#include <ctype.h>

	/* subroutines done by macros */
	#define min(A,B) ((A)<(B) ? (A) : (B))
	#define max(A,B) ((A)>(B) ? (A) : (B))
	#define maxeql(A,B) if (A < (B)) A = (B);
	#define mineql(A,B) if (A > (B)) A = (B);
	#define eatarg0 (argc--, argv++)
	#define arrayLength(A) ((sizeof A)/ (sizeof A[0]))

	FILE *infile;
	char *fname;

	/* Routines to print error messages of varying severity */

	/* externally visible variables */
	int warncnt;
	char *myname;

	void getname (char *arg) {
	/* Save name of invoking program for use by error routines */
	register char *p;
	p = strrchr (arg, '/');
	if (p == NULL)
	myname = arg;
	else
	myname = ++p;
	}

	static void introduction (void) {
	warncnt++;
	fflush (stdout);
	if (myname != NULL)
	fprintf (stderr, "%s: ", myname);
	}

	void warn (char *fmt, ...) {
	va_list args;
	introduction ();
	va_start (args, fmt);
	vfprintf (stderr, fmt, args);
	va_end (args);
	fputc ('\n', stderr);
	fflush (stderr);
	}

	void quit (char *fmt, ...) {
	va_list args;
	introduction ();
	va_start (args, fmt);
	vfprintf (stderr, fmt, args);
	va_end (args);
	fputc ('\n', stderr);
	fflush (stderr);
	exit (1);
	}

	void fatal (char *fmt, ...) {
	va_list args;
	introduction ();
	va_start (args, fmt);
	vfprintf (stderr, fmt, args);
	va_end (args);
	fprintf (stderr, "\nbetter get help!\n");
	fflush (stderr);
	abort ();
	}

	int toption = 0;
	int dqt[16][64];

	int get1 (void) {
	unsigned char x;
	if (fread(&x, 1, 1, infile) == 0)
	quit ("unexpected EOF");
	return x;
	}

	int get2 (void) {
	int x;

	x = get1() << 8;
	return x \| get1();
	}

	void eatmarker (int kind) {
	int l, c;
	l = get2();
	printf ("%02x len=%d\n", kind, l);
	for (l -= 2; l > 0; l--)
	get1();
	}

	char *sofName[16] = {
	"Baseline sequential DCT - Huffman coding",
	"Extended sequential DCT - Huffman coding",
	"Progressive DCT - Huffman coding",
	"Lossless - Huffman coding",
	"4 is otherwise used",
	"Sequential DCT - differential Huffman coding",
	"Progressive DCT - differential Huffman coding",
	"Lossless - differential Huffman coding",
	"8 is reserved",
	"Extended Sequential DCT - arithmetic coding",
	"Progressive DCT - arithmetic coding",
	"Lossless - arithmetic coding",
	"c is otherwise used",
	"Sequential DCT - differential arithmetic coding",
	"Progressive DCT - differential arithmetic coding",
	"Lossless - differential arithmetic coding"
	};

	void get_sof (int kind) {
	int i, length, height, width, precision, ncomponents;
	int id, sf, tab;
	length = get2();
	precision = get1();
	height = get2();
	width = get2();
	ncomponents = get1();
	printf ("SOF%d:\t%s\n", kind - 0xc0, sofName[kind - 0xc0]);
	printf ("\t%d wide, %d high, %d deep, %d components\n",
	width, height, precision, ncomponents);
	for (i = 0; i < ncomponents; i++) {
	id = get1();
	sf = get1();
	tab = get1();
	printf ("\tcomponent %d: %d hsample, %d vsample, quantization table %d\n",
	id, sf >> 4, sf & 0xf, tab);
	}
	}

	void get_com (int kind) {
	int l, c;
	l = get2();
	printf ("COM len=%d '", l);
	for (l -= 2; l > 0; l--)
	putchar (c = get1());
	printf ("'\n");
	}

	void get_app (int kind) {
	int l, c, first;
	char buf[6];
	int nbuf, nok;
	l = get2();
	printf ("APP%d len=%d\n", kind - 0xe0, l);
	nbuf = 0;
	nok = 0;
	first = 1;
	/* dump printable strings in comment */
	for (l -= 2; l > 0; l--){
	c = get1();
	if(isprint(c)){
	if(nbuf >= sizeof buf){
	if(!first && nbuf == nok)
	printf(" ");
	printf("%.*s", nbuf, buf);
	nbuf = 0;
	first = 0;
	}
	buf[nbuf++] = c;
	nok++;
	}else{
	if(nok >= sizeof buf)
	if(nbuf > 0)
	printf("%.*s", nbuf, buf);
	nbuf = 0;
	nok = 0;
	}
	}
	if(nok >= sizeof buf)
	if(nbuf > 0){
	if(!first && nbuf == nok)
	printf(" ");
	printf("%.*s", nbuf, buf);
	}
	}

	void get_dac (int kind) {
	eatmarker (kind);
	}

	int get1dqt (void) {
	int t, p, i, *tab;
	t = get1();
	p = t >> 4;
	t = t & 0xf;
	printf ("DQT:\tp = %d, table = %d\n", p, t);
	tab = &dqt[t][0];
	for (i = 0; i < 64; i++)
	tab[i] = p ? get2() : get1();
	if (toption) {
	for (i = 0; i < 64; i++)
	printf ("\t%q[%02d] = %d\n", i, tab[i]);
	}
	return p ? 65 : 129;
	}

	void get_dqt (int kind) {
	int length;
	length = get2() - 2;
	while (length > 0)
	length -= get1dqt();
	}

	int get1dht (void) {
	int l, tcth, p, i, j, v[16], vv[16][256];
	tcth = get1();
	printf ("DHT:\tclass = %d, table = %d\n", tcth >> 4, tcth & 0xf);
	for (i = 0; i < 16; i++)
	v[i] = get1();
	l = 17;
	for (i = 0; i < 16; i++)
	for (j = 0; j < v[i]; j++) {
	vv[i][j] = get1();
	l += 1;
	}
	if (toption) {
	for (i = 0; i < 16; i++)
	printf ("\t%l[%02d] = %d\n", i+1, v[i]);
	for (i = 0; i < 16; i++)
	for (j = 0; j < v[i]; j++)
	printf ("\t%v[%02d,%02d] = %d\n", i+1, j+1, vv[i][j]);
	}
	return l;
	}

	void get_dht (int kind) {
	int length;
	length = get2() - 2;
	while (length > 0)
	length -= get1dht();
	}

	void get_sos (int kind) {
	int i, length, ncomponents, id, dcac, ahal;
	length = get2();
	ncomponents = get1();
	printf ("SOS:\t%d components\n", ncomponents);
	for (i = 0; i < ncomponents; i++) {
	id = get1();
	dcac = get1();
	printf ("\tcomponent %d: %d DC, %d AC\n", id, dcac >> 4, dcac & 0xf);
	}
	printf ("\tstart spectral %d\n", get1());
	printf ("\tend spectral %d\n", get1());
	ahal = get1();
	printf ("\tah = %d, al = %d\n", ahal >> 4, ahal &0xf);
	}

	main (int argc, char *argv[]) {
	int l, stuff, i, j, c;
	while (argc > 1 && argv[1][0] == '-') {
	switch (argv[1][1]) {
	case 't':
	toption = 1;
	break;
	default:
	warn ("bad option '%c'", argv[1][1]);
	}
	eatarg0;
	}
	fname = argv[1];
	infile = fopen (fname, "r");
	if (infile == NULL)
	quit ("can't open %s\n", fname);
	Start:
	/* if (get1() != 0xff \|\| get1() != 0xd8) */
	/* quit ("not JFIF"); */
	/* printf ("SOI\n"); */
	/* get_app (0xe0); */
	for (;;) {
	c = get1();
	if (c != 0xff)
	quit ("expected marker, got %2x", c);
	do {
	c = get1();
	} while (c == 0xff);
	marker:
	switch (c) {
	case 0xc0: case 0xc1: case 0xc2: case 0xc3:
	case 0xc5: case 0xc6: case 0xc7:
	case 0xc8: case 0xc9: case 0xca: case 0xcb:
	case 0xcd: case 0xce: case 0xcf:
	get_sof (c);
	break;
	case 0xc4:
	get_dht (c);
	break;
	case 0xcc:
	get_dac (c);
	break;
	case 0xd8:
	printf ("SOI\n");
	break;
	case 0xe0: case 0xe1: case 0xe2: case 0xe3:
	case 0xe4: case 0xe5: case 0xe6: case 0xe7:
	case 0xe8: case 0xe9: case 0xea: case 0xeb:
	case 0xec: case 0xed: case 0xee: case 0xef:
	get_app(c);
	break;
	case 0xda:
	get_sos (c);
	goto newentropy;
	case 0xdb:
	get_dqt (c);
	break;
	case 0xfe:
	get_com (c);
	break;
	case 0xd9:
	printf ("EOI\n");
	if((c=getc(infile)) == EOF)
	exit(0);
	ungetc(c, infile);
	goto Start;
	default:
	eatmarker (c);
	}
	continue;
	newentropy:
	l = stuff = 0;
	entropy:
	while ((c = get1()) != 0xff)
	l += 1;
	while (c == 0xff)
	c = get1();
	if (c == 0) {
	stuff += 1;
	goto entropy;
	}
	printf ("sequence length %d with %d stuffs\n", l, stuff);
	if (0xd0 <= c && c <= 0xd7) {
	printf ("restart %d\n", c - 0xd0);
	goto newentropy;
	}
	goto marker;
	}
	}