posttek.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/*
 *
 * posttek - PostScript translator for tektronix 4014 files
 *
 * A program that can be used to translate tektronix 4014 files into PostScript.
 * Most of the code was borrowed from the tektronix 4014 emulator that was written
 * for DMDs. Things have been cleaned up some, but there's still plently that
 * could be done.
 *
 * The PostScript prologue is copied from *prologue before any of the input files
 * are translated. The program expects that the following PostScript procedures
 * are defined in that file:
 *
 *	setup
 *
 *	  mark ... setup -
 *
 *	    Handles special initialization stuff that depends on how the program
 *	    was called. Expects to find a mark followed by key/value pairs on the
 *	    stack. The def operator is applied to each pair up to the mark, then
 *	    the default state is set up.
 *
 *	pagesetup
 *
 *	  page pagesetup -
 *
 *	    Does whatever is needed to set things up for the next page. Expects
 *	    to find the current page number on the stack.
 *
 *	v
 *
 *	  mark dx1 dy1 ... dxn dyn x y v mark
 *
 *	    Draws the vector described by the numbers on the stack. The top two
 *	    numbers are the starting point. The rest are relative displacements
 *	    from the preceeding point. Must make sure we don't put too much on
 *	    the stack!
 *
 *	t
 *
 *	  x y string t -
 *
 *	    Prints the string that's on the top of the stack starting at point
 *	    (x, y).
 *
 *	p
 *
 *	  x y p -
 *
 *	    Marks the point (x, y) with a circle whose radius varies with the
 *	    current intensity setting.
 *
 *	i
 *
 *	  percent focus i -
 *
 *	    Changes the size of the circle used to mark individual points to
 *	    percent of maximum for focused mode (focus=1) or defocused mode
 *	    (focus=0). The implementation leaves much to be desired!
 *
 *	l
 *
 *	  mark array l mark
 *
 *	    Set the line drawing mode according to the description given in array.
 *	    The arrays that describe the different line styles are declared in
 *	    STYLES (file posttek.h). The array really belongs in the prologue!
 *
 *	w
 *
 *	  n w -
 *
 *	    Adjusts the line width for vector drawing. Used to select normal (n=0)
 *	    or defocused (n=1) mode.
 *
 *	f
 *
 *	  size f -
 *
 *	    Changes the size of the font that's used to print characters in alpha
 *	    mode. size is the tektronix character width and is used to choose an
 *	    appropriate point size in the current font.
 *
 *	done
 *
 *	  done
 *
 *	    Makes sure the last page is printed. Only needed when we're printing
 *	    more than one page on each sheet of paper.
 *
 * The default line width is zero, which forces lines to be one pixel wide. That
 * works well on 'write to black' engines but won't be right for 'write to white'
 * engines. The line width can be changed using the -w option, or you can change
 * the initialization of linewidth in the prologue.
 *
 * Many default values, like the magnification and orientation, are defined in 
 * the prologue, which is where they belong. If they're changed (by options), an
 * appropriate definition is made after the prologue is added to the output file.
 * The -P option passes arbitrary PostScript through to the output file. Among
 * other things it can be used to set (or change) values that can't be accessed by
 * other options.
 *
 */

#include <stdio.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 the prologue */
#include "ext.h"			/* external variable definitions */
#include "posttek.h"			/* control codes and other definitions */

char	*optnames = "a:c:f:m:n:o:p:w:x:y:A:C:E:J:L:P:R:DI";

char	*prologue = POSTTEK;		/* default PostScript prologue */
char	*formfile = FORMFILE;		/* stuff for multiple pages per sheet */

int	formsperpage = 1;		/* page images on each piece of paper */
int	copies = 1;			/* and this many copies of each sheet */

int	charheight[] = CHARHEIGHT;	/* height */
int	charwidth[] = CHARWIDTH;	/* and width arrays for tek characters */
int	tekfont = TEKFONT;		/* index into charheight[] and charwidth[] */

char	intensity[] = INTENSITY;	/* special point intensity array */
char	*styles[] = STYLES;		/* description of line styles */
int	linestyle = 0;			/* index into styles[] */
int	linetype = 0;			/* 0 for normal, 1 for defocused */

int	dispmode = ALPHA;		/* current tektronix state */
int	points = 0;			/* points making up the current vector */
int	characters = 0;			/* characters waiting to be printed */
int	pen = UP;			/* just for point plotting */
int	margin = 0;			/* left edge - ALPHA state */

Point	cursor;				/* should be current cursor position */

Fontmap	fontmap[] = FONTMAP;		/* for translating font names */
char	*fontname = "Courier";		/* use this PostScript font */

int	page = 0;			/* page we're working on */
int	printed = 0;			/* printed this many pages */

FILE	*fp_in;				/* read from this file */
FILE	*fp_out = stdout;		/* and write stuff here */
FILE	*fp_acct = NULL;		/* for accounting data */

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

main(agc, agv)

    int		agc;
    char	*agv[];

{

/*
 *
 * A simple program that can be used to translate tektronix 4014 files into
 * PostScript. Most of the code was taken from the DMD tektronix 4014 emulator,
 * although things have been cleaned up some.
 *
 */

    argv = agv;				/* so everyone can use them */
    argc = agc;

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

    init_signals();			/* sets up interrupt handling */
    header();				/* PostScript header comments */
    options();				/* handle the command line options */
    setup();				/* for PostScript */
    arguments();			/* followed by each input file */
    done();				/* print the last page etc. */
    account();				/* job accounting data */

    exit(x_stat);			/* nothing could be wrong */

}   /* End of main */

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

init_signals()

{

/*
 *
 * Make sure we handle interrupts.
 *
 */

    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);
    }   /* End else */

    signal(SIGTERM, interrupt);

}   /* End of init_signals */

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

header()

{

    int		ch;			/* return value from getopt() */
    int		old_optind = optind;	/* for restoring optind - should be 1 */

/*
 *
 * Scans the option list looking for things, like the prologue file, that we need
 * right away but could be changed from the default. Doing things this way is an
 * attempt to conform to Adobe's latest file structuring conventions. In particular
 * they now say there should be nothing executed in the prologue, and they have
 * added two new comments that delimit global initialization calls. Once we know
 * where things really are we write out the job header, follow it by the prologue,
 * and then add the ENDPROLOG and BEGINSETUP comments.
 *
 */

    while ( (ch = getopt(argc, argv, optnames)) != EOF )
	if ( ch == 'L' )
	    prologue = optarg;
	else if ( ch == '?' )
	    error(FATAL, "");

    optind = old_optind;		/* get ready for option scanning */

    fprintf(stdout, "%s", CONFORMING);
    fprintf(stdout, "%s %s\n", VERSION, PROGRAMVERSION);
    fprintf(stdout, "%s %s\n", DOCUMENTFONTS, ATEND);
    fprintf(stdout, "%s %s\n", PAGES, ATEND);
    fprintf(stdout, "%s", ENDCOMMENTS);

    if ( cat(prologue) == FALSE )
	error(FATAL, "can't read %s", prologue);

    fprintf(stdout, "%s", ENDPROLOG);
    fprintf(stdout, "%s", BEGINSETUP);
    fprintf(stdout, "mark\n");

}   /* End of header */

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

options()

{

    int		ch;			/* value returned by getopt() */

/*
 *
 * Reads and processes the command line options. Added the -P option so arbitrary
 * PostScript code can be passed through. Expect it could be useful for changing
 * definitions in the prologue for which options have not been defined.
 *
 */

    while ( (ch = getopt(argc, argv, optnames)) != EOF )  {
	switch ( ch )  {
	    case 'a':			/* aspect ratio */
		    fprintf(stdout, "/aspectratio %s def\n", optarg);
		    break;

	    case 'c':			/* copies */
		    copies = atoi(optarg);
		    fprintf(stdout, "/#copies %s store\n", optarg);
		    break;

	    case 'f':			/* use this PostScript font */
		    fontname = get_font(optarg);
		    fprintf(stdout, "/font /%s def\n", fontname);
		    break;

	    case 'm':			/* magnification */
		    fprintf(stdout, "/magnification %s def\n", optarg);
		    break;

	    case 'n':			/* forms per page */
		    formsperpage = atoi(optarg);
		    fprintf(stdout, "%s %s\n", FORMSPERPAGE, optarg);
		    fprintf(stdout, "/formsperpage %s def\n", optarg);
		    break;

	    case 'o':			/* output page list */
		    out_list(optarg);
		    break;

	    case 'p':			/* landscape or portrait mode */
		    if ( *optarg == 'l' )
			fprintf(stdout, "/landscape true def\n");
		    else fprintf(stdout, "/landscape false def\n");
		    break;

	    case 'w':			/* line width */
		    fprintf(stdout, "/linewidth %s def\n", optarg);
		    break;

	    case 'x':			/* shift horizontally */
		    fprintf(stdout, "/xoffset %s def\n", optarg);
		    break;

	    case 'y':			/* and vertically on the page */
		    fprintf(stdout, "/yoffset %s def\n", optarg);
		    break;

	    case 'A':			/* force job accounting */
	    case 'J':
		    if ( (fp_acct = fopen(optarg, "a")) == NULL )
			error(FATAL, "can't open accounting file %s", optarg);
		    break;

	    case 'C':			/* copy file straight to output */
		    if ( cat(optarg) == FALSE )
			error(FATAL, "can't read %s", optarg);
		    break;

	    case 'E':			/* text font encoding */
		    fontencoding = optarg;
		    break;

	    case 'L':			/* PostScript prologue file */
		    prologue = optarg;
		    break;

	    case 'P':			/* PostScript pass through */
		    fprintf(stdout, "%s\n", optarg);
		    break;

	    case 'R':			/* special global or page level request */
		    saverequest(optarg);
		    break;

	    case 'D':			/* debug flag */
		    debug = ON;
		    break;

	    case 'I':			/* ignore FATAL errors */
		    ignore = ON;
		    break;

	    case '?':			/* don't know the option */
		    error(FATAL, "");
		    break;

	    default:			/* don't know what to do for ch */
		    error(FATAL, "missing case for option %c", ch);
		    break;
	}   /* End switch */
    }	/* End while */

    argc -= optind;
    argv += optind;

}   /* End of options */

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

char *get_font(name)

    char	*name;			/* name the user asked for */

{

    int		i;			/* for looking through fontmap[] */

/*
 *
 * Called from options() to map a user's font name into a legal PostScript name.
 * If the lookup fails *name is returned to the caller. That should let you choose
 * any PostScript font.
 *
 */

    for ( i = 0; fontmap[i].name != NULL; i++ )
	if ( strcmp(name, fontmap[i].name) == 0 )
	    return(fontmap[i].val);

    return(name);

}   /* End of get_font */

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

setup()

{

/*
 *
 * Handles things that must be done after the options are read but before the
 * input files are processed.
 *
 */

    writerequest(0, stdout);		/* global requests eg. manual feed */
    setencoding(fontencoding);
    fprintf(stdout, "setup\n");

    if ( formsperpage > 1 )  {
	if ( cat(formfile) == FALSE )
	    error(FATAL, "can't read %s", formfile);
	fprintf(stdout, "%d setupforms\n", formsperpage);
    }	/* End if */

    fprintf(stdout, "%s", ENDSETUP);

}   /* End of setup */

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

arguments()

{

/*
 *
 * Makes sure all the non-option command line arguments are processed. If we get
 * here and there aren't any arguments left, or if '-' is one of the input files
 * we'll process stdin.
 *
 */

    if ( argc < 1 )
	statemachine(fp_in = stdin);
    else  {				/* at least one argument is left */
	while ( argc > 0 )  {
	    if ( strcmp(*argv, "-") == 0 )
		fp_in = stdin;
	    else if ( (fp_in = fopen(*argv, "r")) == NULL )
		error(FATAL, "can't open %s", *argv);
	    statemachine(fp_in);
	    if ( fp_in != stdin )
		fclose(fp_in);
	    argc--;
	    argv++;
	}   /* End while */
    }   /* End else */

}   /* End of arguments */

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

done()

{

/*
 *
 * Finished with all the input files, so mark the end of the pages with a TRAILER
 * comment, make sure the last page prints, and add things like the PAGES comment
 * that can only be determined after all the input files have been read.
 *
 */

    fprintf(stdout, "%s", TRAILER);
    fprintf(stdout, "done\n");
    fprintf(stdout, "%s %s\n", DOCUMENTFONTS, fontname);
    fprintf(stdout, "%s %d\n", PAGES, printed);

}   /* End of done */

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

account()

{

/*
 *
 * Writes an accounting record to *fp_acct provided it's not NULL. Accounting
 * is requested using the -A or -J options.
 *
 */

    if ( fp_acct != NULL )
	fprintf(fp_acct, " print %d\n copies %d\n", printed, copies);

}   /* End of account */

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

statemachine(fp)

    FILE	*fp;			/* used to set fp_in */

{

/*
 *
 * Controls the translation of the next input file. Tektronix states (dispmode)
 * are typically changed in control() and esc().
 *
 */

    redirect(-1);			/* get ready for the first page */
    formfeed();
    dispmode = RESET;

    while ( 1 )
	switch ( dispmode )  {
	    case RESET:
		    reset();
		    break;

	    case ALPHA:
		    alpha();
		    break;

	    case GIN:
		    gin();
		    break;

	    case GRAPH:
		    graph();
		    break;

	    case POINT:
	    case SPECIALPOINT:
		    point();
		    break;

	    case INCREMENTAL:
		    incremental();
		    break;

	    case EXIT:
		    formfeed();
		    return;
	}   /* End switch */

}   /* End of statemachine */

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

reset()

{

/*
 *
 * Called to reset things, typically only at the beginning of each input file.
 *
 */

    tekfont = -1;
    home();
    setfont(TEKFONT);
    setmode(ALPHA);

}   /* End of reset */

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

alpha()

{

    int		c;			/* next character */
    int		x, y;			/* cursor will be here when we're done */

/*
 *
 * Takes care of printing characters in the current font.
 *
 */

    if ( (c = nextchar()) == OUTMODED )
	return;

    if ( (c < 040) && ((c = control(c)) <= 0) )
	return;

    x = cursor.x;			/* where the cursor is right now */
    y = cursor.y;

    switch ( c )  {
	case DEL:
		return;

	case BS:
		if ((x -= charwidth[tekfont]) < margin)
		    x = TEKXMAX - charwidth[tekfont];
		break;

	case NL:
		y -= charheight[tekfont];
		break;