/* 
 * dvipages.c: print out page info of specified DVI file.
 * 
 *     [1998/03/09] OSHIRO Naoki. Assemble from xdvi.page source.
 *   
 *     $Log:$
 */

static char rcsid[]="$Id:$";

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/stat.h>
#include <setjmp.h>

#define PAGENUM
#define PTEX

#define	OPEN_MODE	"r"
#define	_Xconst	const
#define	NORETURN	volatile

/********************************
 *	 Types and data		*
 *******************************/

#ifndef	EXTERN
#define	EXTERN	extern
#define	INIT(x)
#define	NTINIT(x)
#endif

typedef	unsigned char ubyte;
#define	Boolean	char
#define	True	1
#define	False	0

#define	MAXDIM		32767
/*
 *	pixel_conv is currently used only for converting absolute positions
 *	to pixel values; although normally it should be
 *		((int) ((x) / shrink_factor + (1 << 15) >> 16)),
 *	the rounding is achieved instead by moving the constant 1 << 15 to
 *	PAGE_OFFSET in dvi_draw.c.
 */
#define	pixel_conv(x)		((int) ((x) / shrink_factor >> 16))
#define	pixel_round(x)		((int) ROUNDUP(x, shrink_factor << 16))
#define	spell_conv0(n, f)	((long) (n * f))
#define	spell_conv(n)		spell_conv0(n, dimconv)

/* entries below with the characters 'dvi' in them are actually stored in
   scaled pixel units */

int	current_page;
int	total_pages;
double	dimconv;
int	n_files_left	INIT(32767);	/* for LRU closing of fonts */
time_t	dvi_time;		/* last mod. time for dvi file */
int	page_w, page_h;

/*
 * Table of page offsets in DVI file, indexed by page number - 1.
 * Initialized in prepare_pages().
 */

#ifdef PAGENUM
typedef struct {
    long offset;
    int number;
} PAGE_INDEX;

PAGE_INDEX *page_index;
#else	/* !PAGENUM */
long	*page_offset;
#endif	/* PAGENUM */

#ifndef	BDPI
#define	BDPI	300
#endif

int	pixels_per_inch	NTINIT(BDPI);
int	offset_x, offset_y;
int	unshrunk_paper_w, unshrunk_paper_h;
int	unshrunk_page_w, unshrunk_page_h;
int	density		NTINIT(40);
double	specialConv;

char	*dvi_name	INIT(NULL);
FILE	*dvi_file;				/* user's file */
jmp_buf	dvi_env;	/* mechanism to communicate dvi file errors */

#define one(fp)		((unsigned char) getc(fp))
#define sone(fp)	((long) one(fp))
#define two(fp)		num (fp, 2)
#define stwo(fp)	snum(fp, 2)
#define four(fp)	num (fp, 4)
#define sfour(fp)	snum(fp, 4)

/*
 *	Mnemonics for bytes in dvi file.
 */

#define	SETCHAR0	0
#define	SET1		128
#ifdef	KANJI
#define	SET2		129
#endif	/* KANJI */
#define	SETRULE		132
#define	PUT1		133
#ifdef	KANJI
#define	PUT2		134
#endif	/* KANJI */
#define	PUTRULE		137
#define	NOP		138
#define	BOP		139
#define	EOP		140
#define	PUSH		141
#define	POP		142
#define	RIGHT1		143
#define	RIGHT2		144
#define	RIGHT3		145
#define	RIGHT4		146
#define	W0		147
#define	W1		148
#define	W2		149
#define	W3		150
#define	W4		151
#define	X0		152
#define	X1		153
#define	X2		154
#define	X3		155
#define	X4		156
#define	DOWN1		157
#define	DOWN2		158
#define	DOWN3		159
#define	DOWN4		160
#define	Y0		161
#define	Y1		162
#define	Y2		163
#define	Y3		164
#define	Y4		165
#define	Z0		166
#define	Z1		167
#define	Z2		168
#define	Z3		169
#define	Z4		170
#define	FNTNUM0		171
#define	FNT1		235
#define	FNT2		236
#define	FNT3		237
#define	FNT4		238
#define	XXX1		239
#define	XXX2		240
#define	XXX3		241
#define	XXX4		242
#define	FNTDEF1		243
#define	FNTDEF2		244
#define	FNTDEF3		245
#define	FNTDEF4		246
#define	PRE		247
#define	POST		248
#define	POSTPOST	249
#define	SREFL		250
#define	EREFL		251
#ifdef	PTEX
#define	TDIR	255
#endif	/* KANJI */

#define	TRAILER		223	/* Trailing bytes at end of file */

static	struct stat fstatbuf;

/*
 * DVI preamble and postamble information.
 */
static	char	job_id[300];
static	long	numerator, denominator, magnification;

/*
 * Offset in DVI file of last page, set in read_postamble().
 */
static	long	last_page_offset;

char *
xmalloc(size, why)
	unsigned	size;
	_Xconst char	*why;
{
	char *mem = malloc(size);

	if (mem == NULL) return NULL;
	    
	return mem;
}

unsigned long
num(fp, size)
	register FILE *fp;
	register int size;
{
	register long x = 0;

	while (size--) x = (x << 8) | one(fp);
	return x;
}

long
snum(fp, size)
	register FILE *fp;
	register int size;
{
	register long x;

#ifdef	__STDC__
	x = (signed char) getc(fp);
#else
	x = (unsigned char) getc(fp);
	if (x & 0x80) x -= 0x100;
#endif
	while (--size) x = (x << 8) | one(fp);
	return x;
}

/*
 *      process_preamble reads the information in the preamble and stores
 *      it into global variables for later use.
 */
static	void
process_preamble()
{
	ubyte   k;

	if (one(dvi_file) != PRE) return;
#ifdef PTEX
	k = one(dvi_file);
	if (k != 2 && k != 3)
#else 
	if (one(dvi_file) != 2)
#endif
		return;
	numerator     = four(dvi_file);
	denominator   = four(dvi_file);
	magnification = four(dvi_file);
	dimconv = (((double) numerator * magnification)
		/ ((double) denominator * 1000.));
	dimconv = dimconv * (((long) pixels_per_inch)<<16) / 254000;
	specialConv = pixels_per_inch * magnification / 1000000.0;
	k = one(dvi_file);
	fread(job_id, sizeof(char), (int) k, dvi_file);
	job_id[k] = '\0';
}

/*
 *      find_postamble locates the beginning of the postamble
 *	and leaves the file ready to start reading at that location.
 */
#define	TMPSIZ	516	/* 4 trailer bytes + 512 junk bytes allowed */
static	void
find_postamble()
{
	long	pos;
	ubyte	temp[TMPSIZ];
	ubyte	*p;
	ubyte	*p1;
	ubyte	byte;

	fseek(dvi_file, (long) 0, 2);
	pos = ftell(dvi_file) - TMPSIZ;
	if (pos < 0) pos = 0;
	fseek(dvi_file, pos, 0);
	p = temp + fread((char *) temp, sizeof(char), TMPSIZ, dvi_file);
	for (;;) {
	    p1 = p;
	    while (p1 > temp && *(--p1) != TRAILER) ;
	    p = p1;
	    while (p > temp && *(--p) == TRAILER) ;
	    if (p <= p1 - 4) break;	/* found 4 TRAILER bytes */
	    if (p <= temp) return;
	}
	pos += p - temp;
	byte = *p;
	while (byte == TRAILER) {
	    fseek(dvi_file, --pos, 0);
	    byte = one(dvi_file);
	}
#ifdef PTEX
	if (byte != 2 && byte != 3)
#else
	if (byte != 2)
#endif
	    return;
	fseek(dvi_file, pos - 4, 0);
	fseek(dvi_file, sfour(dvi_file), 0);
}


/*
 *      read_postamble reads the information in the postamble,
 *	storing it into global variables.
 *      It also takes care of reading in all of the pixel files for the fonts
 *      used in the job.
 */
static	void
read_postamble()
{
	ubyte   cmnd;
	struct font	*fontp;
	struct font	**fontpp;

	if (one(dvi_file) != POST)
	    return;
	last_page_offset = four(dvi_file);
	if (numerator != four(dvi_file)
		|| denominator != four(dvi_file)
		|| magnification != four(dvi_file))
	    return;
		/* read largest box height and width */
	unshrunk_page_h = (spell_conv(sfour(dvi_file)) >> 16) + offset_y;
	if (unshrunk_page_h < unshrunk_paper_h)
	    unshrunk_page_h = unshrunk_paper_h;
	unshrunk_page_w = (spell_conv(sfour(dvi_file)) >> 16) + offset_x;
	if (unshrunk_page_w < unshrunk_paper_w)
	    unshrunk_page_w = unshrunk_paper_w;
	(void) two(dvi_file);	/* max stack size */
	total_pages = two(dvi_file);
}

static	void
prepare_pages()
{
	int i;
	     
#ifdef	PAGENUM
	long offset;

	page_index = (PAGE_INDEX *)xmalloc((unsigned)total_pages
					   * sizeof(PAGE_INDEX),
					   "page directory");
	for (offset = last_page_offset, i = total_pages; i > 0; i--) {
	    fseek(dvi_file, offset, 0);
	    if (one(dvi_file) != BOP) {
  		return;
	    }
	    page_index[i-1].offset = offset;
	    page_index[i-1].number = four(dvi_file); /* Read c[0] */
	    fseek(dvi_file, (long)(9*4), 1);
	    offset = four(dvi_file);
	}

#else
	page_offset = (long *) xmalloc((unsigned) total_pages * sizeof(long),
	    "page directory");
	i = total_pages;
	page_offset[--i] = last_page_offset;
	fseek(dvi_file, last_page_offset, 0);
	/*
	 * Follow back pointers through pages in the DVI file,
	 * storing the offsets in the page_offset table.
	 */
	while (i > 0) {
	    fseek(dvi_file, (long) (1+4+(9*4)), 1);
	    fseek(dvi_file, page_offset[--i] = four(dvi_file), 0);
	}
#endif	/* PAGENUM */
}

/*
 *	init_dvi_file is the main subroutine for reading the startup
 *	information from the dvi file.  Returns True on success.
 */

static	Boolean
init_dvi_file()
{
	(void) fstat(fileno(dvi_file), &fstatbuf);
	if (S_ISDIR(fstatbuf.st_mode))
	    return False;
	dvi_time = fstatbuf.st_mtime;
	process_preamble();
	find_postamble();
	read_postamble();
	prepare_pages();
}

/**
 **	open_dvi_file opens the dvi file and calls init_dvi_file() to
 **	initialize it.
 **/

void
open_dvi_file()
{
	char	*errmsg;
	int	n;
	char	*file;

	if ((errmsg = (char *) setjmp(dvi_env)) != NULL) return;

	n = strlen(dvi_name);
	file = dvi_name;

	/*
	 * Try foo.dvi before foo, in case there's an executable foo with
	 * documentation foo.tex.  Unless it already ends with ".dvi".
	 */
	if (n < sizeof(".dvi")
		|| strcmp(dvi_name + n - sizeof(".dvi") + 1, ".dvi") != 0) {
	    dvi_name = xmalloc((unsigned) n + sizeof(".dvi"), "dvi file name");
	    strcpy(dvi_name, file);
	    strcat(dvi_name, ".dvi");
	}
        dvi_file = fopen(dvi_name, OPEN_MODE);
        init_dvi_file();
}

int main(int argc, char **argv)
{
    int i;
    
    argv++;
    dvi_name = *argv;
    open_dvi_file();
    printf("%d", total_pages);
#ifdef PAGENUM
    printf(" ");
    for (i = 0; i<total_pages; i++)
	printf("%d ", page_index[i].number);
#endif
    printf("\n");
}