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/*

 * postreverse - reverse the page order in certain PostScript files.

 *

 * Page reversal relies on being able to locate sections of a document using file

 * structuring comments defined by Adobe (ie. the 1.0 and now 2.0 conventions) and

 * a few I've added. Among other things a minimally conforming document, according

 * to the 1.0 conventions,

 *

 *	1) Marks the end of the prologue with an %%EndProlog comment.

 *

 *	2) Starts each page with a %%Page: comment.

 *

 *	3) Marks the end of all the pages %%Trailer comment.

 *

 *	4) Obeys page independence (ie. pages can be arbitrarily rearranged).

 *

 * The most important change (at least for this program) that Adobe made in going

 * from the 1.0 to the 2.0 structuring conventions was in the prologue. They now

 * say the prologue should only define things, and the global initialization that

 * was in the prologue (1.0 conventions) should now come after the %%EndProlog

 * comment but before the first %%Page: comment and be bracketed by %%BeginSetup

 * and %%EndSetup comments. So a document that conforms to Adobe's 2.0 conventions,

 *

 *	1) Marks the end of the prologue (only definitions) with %%EndProlog.

 *

 *	2) Brackets global initialization with %%BeginSetup and %%EndSetup comments

 *	   which come after the prologue but before the first %Page: comment.

 *

 *	3) Starts each page with a %%Page: comment.

 *

 *	4) Marks the end of all the pages with a %%Trailer comment.

 *

 *	5) Obeys page independence.

 *

 * postreverse can handle documents that follow the 1.0 or 2.0 conventions, but has

 * also been extended slightly so it works properly with the translators (primarily

 * dpost) supplied with this package. The page independence requirement has been

 * relaxed some. In particular definitions exported to the global environment from

 * within a page should be bracketed by %%BeginGlobal and %%EndGlobal comments.

 * postreverse pulls them out of each page and inserts them in the setup section

 * of the document, immediately before it writes the %%EndProlog (for version 1.0)

 * or %%EndSetup (for version 2.0) comments.

 *

 * In addition postreverse accepts documents that choose to mark the end of each

 * page with a %%EndPage: comment, which from a translator's point of view is often

 * a more natural approach. Both page boundary comments (ie. Page: and %%EndPage:)

 * are also accepted, but be warned that everything between consecutive %%EndPage:

 * and %%Page: comments will be ignored.

 *

 * So a document that will reverse properly with postreverse,

 *

 *	1) Marks the end of the prologue with %%EndProlog.

 *

 *	2) May have a %%BeginSetup/%%EndSetup comment pair before the first %%Page:

 *	   comment that brackets any global initialization.

 *

 *	3) Marks the start of each page with a %%Page: comment, or the end of each

 *	   page with a %%EndPage: comment. Both page boundary comments are allowed.

 *

 *	4) Marks the end of all the pages with a %%Trailer comment.

 *

 *	5) Obeys page independence or violates it to a rather limited extent and

 *	   marks the violations with %%BeginGlobal and %%EndGlobal comments.

 *

 * If no file arguments are given postreverse copies stdin to a temporary file and

 * then processes that file. That means the input is read three times (rather than

 * two) whenever we handle stdin. That's expensive, and shouldn't be too difficult

 * to fix, but I haven't gotten around to it yet.

 */

#define _BSD_EXTENSION

#define _POSIX_SOURCE

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <signal.h>

#include <sys/types.h>

#include <fcntl.h>

#include "comments.h"			/* PostScript file structuring comments */

#include "gen.h"			/* general purpose definitions */

#include "path.h"			/* for temporary directory */

#include "ext.h"			/* external variable declarations */

#include "postreverse.h"		/* a few special definitions */

int	page = 1;			/* current page number */

int	forms = 1;			/* forms per page in the input file */

char	*temp_dir = TEMPDIR;		/* temp directory for copying stdin */

Pages	pages[1000];			/* byte offsets for all pages */

int	next_page = 0;			/* next page goes here */

long	start;				/* starting offset for next page */

long	endoff = -1;			/* offset where TRAILER was found */

int	noreverse = FALSE;		/* don't reverse pages if TRUE */

char	*endprolog = ENDPROLOG;		/* occasionally changed to ENDSETUP */

double	version = 3.3;			/* of the input file */

int	ignoreversion = FALSE;		/* ignore possible forms.ps problems */

char	buf[2048];			/* line buffer for input file */

FILE	*fp_in;				/* stuff is read from this file */

FILE	*fp_out = stdout;		/* and written here */

main(agc, agv)

    int		agc;

    char	*agv[];

{

/*

 * A simple program that reverses the pages in specially formatted PostScript

 * files. Will work with all the translators in this package, and should handle

 * any document that conforms to Adobe's version 1.0 or 2.0 file structuring

 * conventions. Only one input file is allowed, and it can either be a named (on

 * the command line) file or stdin.

 */

    argc = agc;				/* other routines may want them */

    argv = agv;

    prog_name = argv[0];		/* just for error messages */

    init_signals();			/* sets up interrupt handling */

    options();				/* first get command line options */

    arguments();			/* then process non-option arguments */

    done();				/* and clean things up */

    exit(x_stat);			/* not much could be wrong */

    return 0;

}

init_signals()

{

/*

 * Makes sure we handle interrupts properly.

 */

    if ( signal(SIGINT, interrupt) == SIG_IGN )  {

	signal(SIGINT, SIG_IGN);

	signal(SIGQUIT, SIG_IGN);

	signal(SIGHUP, SIG_IGN);

    } else {

	signal(SIGHUP, interrupt);

	signal(SIGQUIT, interrupt);

    }

    signal(SIGTERM, interrupt);

}

options()

{

    int		ch;			/* return value from getopt() */

    char	*optnames = "n:o:rvT:DI";

    extern char	*optarg;		/* used by getopt() */

    extern int	optind;

/*

 *

 * Reads and processes the command line options. The -r option (ie. the one that

 * turns page reversal off) is really only useful if you want to take dpost output

 * and produce a page independent output file. In that case global definitions

 * made within pages and bracketed by %%BeginGlobal/%%EndGlobal comments will be

 * moved into the prologue or setup section of the document.

 *

 */

    while ( (ch = getopt(argc, argv, optnames)) != EOF )  {

	switch ( ch )  {

	    case 'n':			/* forms per page */

		    if ( (forms = atoi(optarg)) <= 0 )

			error(FATAL, "illegal forms request %s", optarg);

		    break;

	    case 'o':			/* output page list */

		    out_list(optarg);

		    break;

	    case 'r':			/* don't reverse the pages */

		    noreverse = TRUE;

		    break;

	    case 'v':			/* ignore possible forms.ps problems */

		    ignoreversion = TRUE;

		    break;

	    case 'T':			/* temporary file directory */

		    temp_dir = optarg;

		    break;

	    case 'D':			/* debug flag */

		    debug = ON;

		    break;

	    case 'I':			/* ignore FATAL errors */

		    ignore = ON;

		    break;

	    case '?':			/* don't understand the option */

		    error(FATAL, "");

		    break;

	    default:			/* don't know what to do for ch */

		    error(FATAL, "missing case for option %c\n", ch);

		    break;

	}   /* End switch */

    }   /* End while */

    argc -= optind;			/* get ready for non-option args */

    argv += optind;

}   /* End of options */

/*****************************************************************************/

arguments()

{

    char	*name;			/* name of the input file */

/*

 *

 * postreverse only handles one input file at a time, so if there's more than one

 * argument left when we get here we'll quit. If none remain we copy stdin to a

 * temporary file and process that file.

 *

 */

    if ( argc > 1 )			/* can't handle more than one file */

	error(FATAL, "too many arguments");

    if ( argc == 0 )			/* copy stdin to a temporary file */

	name = copystdin();

    else name = *argv;

    if ( (fp_in = fopen(name, "r")) == NULL )

	error(FATAL, "can't open %s", name);

    reverse();

}   /* End of arguments */

/*****************************************************************************/

done()

{

/*

 *

 * Cleans things up after we've finished reversing the pages in the input file.

 * All that's really left to do is remove the temp file, provided we used one.

 *

 */

    if ( temp_file != NULL )

	unlink(temp_file);

}   /* End of done */

/*****************************************************************************/

char *copystdin()

{

    int		fd_out;			/* for the temporary file */

    int		fd_in;			/* for stdin */

    int		count;			/* number of bytes put in buf[] */

/*

 *

 * Copies stdin to a temporary file and returns the pathname of that file to the

 * caller. It's an expensive way of doing things, because it means we end up

 * reading the input file three times - rather than just twice. Could probably be

 * fixed by creating the temporary file on the fly as we read the file the first

 * time.

 *

 */

    if ( (temp_file = tempnam(temp_dir, "post")) == NULL )

	error(FATAL, "can't generate temp file name");

    if ( (fd_out = creat(temp_file, 0660)) == -1 )

	error(FATAL, "can't open %s", temp_file);

    fd_in = fileno(stdin);

    while ( (count = read(fd_in, buf, sizeof(buf))) > 0 )

	if ( write(fd_out, buf, count) != count )

	    error(FATAL, "error writing to %s", temp_file);

    close(fd_out);

    return(temp_file);

}   /* End of copystdin */

/*****************************************************************************/

reverse()

{

/*

 *

 * Begins by looking for the ENDPROLOG comment in the input file. Everything up to

 * that comment is copied to the output file. If the comment isn't found the entire

 * input file is copied and moreprolog() returns FALSE. Otherwise readpages() reads

 * the rest of the input file and remembers (in pages[]) where each page starts and

 * ends. In addition everything bracketed by %%BeginGlobal and %%EndGlobal comments

 * is immediately added to the new prologue (or setup section) and ends up being

 * removed from the individual pages. When readpages() finds the TRAILER comment

 * or gets to the end of the input file we go back to the pages[] array and use

 * the saved offsets to write the pages out in reverse order. Finally everything

 * from the TRAILER comment to the end of the input file is copied to the output

 * file.

 *

 */

    if ( moreprolog(ENDPROLOG) == TRUE )  {

	readpages();

	writepages();

	trailer();

    }	/* End if */

}   /* End of reverse */

/*****************************************************************************/

moreprolog(str)

    char	*str;			/* copy everything up to this string */

{

    int		len;			/* length of FORMSPERPAGE string */

    int		vlen;			/* length of VERSION string */

/*

 *

 * Looks for string *str at the start of a line and copies everything up to that

 * string to the output file. If *str isn't found the entire input file will end

 * up being copied to the output file and FALSE will be returned to the caller.

 * The first call (made from reverse()) looks for ENDPROLOG. Any other call comes

 * from readpages() and will be looking for the ENDSETUP comment.

 * 

 */

    len = strlen(FORMSPERPAGE);

    vlen = strlen(VERSION);

    while ( fgets(buf, sizeof(buf), fp_in) != NULL )  {

	if ( strcmp(buf, str) == 0 )

	    return(TRUE);

	else if ( strncmp(buf, FORMSPERPAGE, len) == 0 )

	    forms = atoi(&buf[len+1]);

	else if ( strncmp(buf, VERSION, vlen) == 0 )

	    version = atof(&buf[vlen+1]);

	fprintf(fp_out, "%s", buf);

    }	/* End while */

    return(FALSE);

}   /* End of moreprolog */

/*****************************************************************************/

readpages()

{

    int		endpagelen;		/* length of ENDPAGE */

    int		pagelen;		/* and PAGE strings */

    int		sawendpage = TRUE;	/* ENDPAGE equivalent marked last page */

    int		gotpage = FALSE;	/* TRUE disables BEGINSETUP stuff */

/*

 *

 * Records starting and ending positions of the requested pages (usually all of

 * them), puts global definitions in the prologue, and remembers where the TRAILER

 * was found.

 *

 * Page boundaries are marked by the strings PAGE, ENDPAGE, or perhaps both.

 * Application programs will normally find one or the other more convenient, so

 * in most cases only one kind of page delimiter will be found in a particular

 * document.

 *

 */

    pages[0].start = ftell(fp_in);	/* first page starts after ENDPROLOG */

    endprolog = ENDPROLOG;

    endpagelen = strlen(ENDPAGE);

    pagelen = strlen(PAGE);

    while ( fgets(buf, sizeof(buf), fp_in) != NULL )

	if ( buf[0] != '%' )

	    continue;

	else if ( strncmp(buf, ENDPAGE, endpagelen) == 0 )  {

	    if ( in_olist(page++) == ON )  {

		pages[next_page].empty = FALSE;

		pages[next_page++].stop = ftell(fp_in);

	    }	/* End if */

	    pages[next_page].start = ftell(fp_in);

	    sawendpage = TRUE;

	    gotpage = TRUE;

	} else if ( strncmp(buf, PAGE, pagelen) == 0 )  {

	    if ( sawendpage == FALSE && in_olist(page++) == ON )  {

		pages[next_page].empty = FALSE;

		pages[next_page++].stop = ftell(fp_in) - strlen(buf);

	    }	/* End if */

	    pages[next_page].start = ftell(fp_in) - strlen(buf);

	    sawendpage = FALSE;

	    gotpage = TRUE;

	} else if ( gotpage == FALSE && strcmp(buf, BEGINSETUP) == 0 )  {

	    fprintf(fp_out, "%s", endprolog);

	    fprintf(fp_out, "%s", BEGINSETUP);

	    moreprolog(ENDSETUP);

	    endprolog = ENDSETUP;

	} else if ( strcmp(buf, BEGINGLOBAL) == 0 )  {

	    moreprolog(ENDGLOBAL);

	} else if ( strcmp(buf, TRAILER) == 0 )  {

	    if ( sawendpage == FALSE )

		pages[next_page++].stop = ftell(fp_in) - strlen(buf);

	    endoff = ftell(fp_in);

	    break;

	}   /* End if */

}   /* End of readpages */

/*****************************************************************************/

writepages()

{

    int		i, j, k;		/* loop indices */

/*

 *

 * Goes through the pages[] array, usually from the bottom up, and writes out all

 * the pages. Documents that print more than one form per page cause things to get

 * a little more complicated. Each physical page has to have its subpages printed

 * in the correct order, and we have to build a few dummy subpages for the last

 * (and now first) sheet of paper, otherwise things will only occasionally work.

 *

 */

    fprintf(fp_out, "%s", endprolog);

    if ( noreverse == FALSE )		/* fill out the first page */

	for ( i = (forms - next_page % forms) % forms; i > 0; i--, next_page++ )

	    pages[next_page].empty = TRUE;

    else forms = next_page;		/* turns reversal off in next loop */

    for ( i = next_page - forms; i >= 0; i -= forms )

	for ( j = i, k = 0; k < forms; j++, k++ )

	    if ( pages[j].empty == TRUE ) {

		if ( ignoreversion == TRUE || version > 3.1 ) {

		    fprintf(fp_out, "%s 0 0\n", PAGE);

		    fprintf(fp_out, "/saveobj save def\n");

		    fprintf(fp_out, "showpage\n");

		    fprintf(fp_out, "saveobj restore\n");

		    fprintf(fp_out, "%s 0 0\n", ENDPAGE);

		} else {

		    fprintf(fp_out, "%s 0 0\n", PAGE);

		    fprintf(fp_out, "save showpage restore\n");

		    fprintf(fp_out, "%s 0 0\n", ENDPAGE);

		}   /* End else */

	    } else copypage(pages[j].start, pages[j].stop);

}   /* End of writepages */

/*****************************************************************************/

copypage(start, stop)

    long	start;			/* starting from this offset */

    long	stop;			/* and ending here */

{

/*

 *

 * Copies the page beginning at offset start and ending at stop to the output

 * file. Global definitions are skipped since they've already been added to the

 * prologue.

 *

 */

    fseek(fp_in, start, 0);

    while ( ftell(fp_in) < stop && fgets(buf, sizeof(buf), fp_in) != NULL )

	if ( buf[0] == '%' && strcmp(buf, BEGINGLOBAL) == 0 )

	    while ( fgets(buf, sizeof(buf), fp_in) != NULL && strcmp(buf, ENDGLOBAL) != 0 ) ;

	else fprintf(fp_out, "%s", buf);

}   /* End of copypage */

/*****************************************************************************/

trailer()

{

/*

 *

 * Makes sure everything from the TRAILER string to EOF is copied to the output

 * file.

 *

 */

    if ( endoff > 0 )  {

	fprintf(fp_out, "%s", TRAILER);

	fseek(fp_in, endoff, 0);

	while ( fgets(buf, sizeof(buf), fp_in) != NULL )

	    fprintf(fp_out, "%s", buf);

    }	/* End if */

}   /* End of trailer */

/*****************************************************************************/