dvi.c

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/*
 * (c) Copyright 1993 by Panagiotis Tsirigotis
 * All rights reserved.  The file named COPYRIGHT specifies the terms 
 * and conditions for redistribution.
 */

static char RCSid[] = "dvi.c,v 1.5 1994/12/20 20:05:15 hardy Exp";

#include <ctype.h>
#include <string.h>

#include "sio.h"

#include "defs.h"


static int get_file_char(fdp)
int *fdp;
{
	return (next_char(*fdp));
}

PRIVATE int get_num(fd, c)
int fd;
int c;
{
	int num = NUM(c);

	for (;;) {
		NEXT_CHAR(fd, c);
		if (c == SIO_EOF)
			error("Unexpected end of file while reading number\n");

		if (isdigit(c)) {
			num *= 10;
			num += NUM(c);
		} else if (isalpha(c))
			error("Unexpected character terminating number: '%c'\n", c);
		else if (c == SPACE || c == NEWLINE)
			break;
		else {
			PUTBACK(fd, c);
			break;
		}
	}
	return (num);
}

/*
 * This function is called for lines starting with '%'
 */
PRIVATE int check_for_new_page(fd)
int fd;
{
	char *line;
	char *page_id = "Page:";
	int id_len = strlen(page_id);
	int new_page = FALSE;
	void start_paragraph();

	while (line = Srdline(fd)) {
		if (line[0] != '%') {
			Sundo(fd, SIO_UNDO_LINE);
			break;
		}
		line_count++;
		if (line[1] != '%')
			continue;
		if (strncmp(&line[2], page_id, id_len) == 0) {
			if (!new_page)
				start_paragraph();
			new_page = TRUE;
		}
	}
	return (new_page);
}


void dvi_process(fd)
int fd;
{
	int c;
	int num;
	int output_string = FALSE;
	int last_cmd = SPACE;
	token_e last_token = TOK_OTHER;
	void process_string();
	void skip_until();
	void skip_bracket();
	void decode_string();

	for (;;) {
		NEXT_CHAR(fd, c);
		if (c == SIO_EOF)
			break;

		if (c == '%') {
			skip_until(fd, NEWLINE);
			last_token = TOK_OTHER;
			continue;
		}
		if (c == SPACE)
			continue;

		if (c == NEWLINE) {
			/*
			 * Peek at the next character to check if it is a line beginning 
			 * with '%%'
			 */
			NEXT_CHAR(fd, c);
			if (c == SIO_EOF)
				break;
			PUTBACK(fd, c);

			if (c != '%')
				continue;

			if (check_for_new_page(fd))
				output_string = FALSE;
			last_token = TOK_OTHER;
			continue;
		}
		if (c == SLASH) {
			for (;;) {
				NEXT_CHAR(fd, c);
				if (c == SIO_EOF)
					error("Reached EOF reading literal\n");
				if (!isalnum(c)) {
					PUTBACK(fd, c);
					break;
				}
			}
			last_token = TOK_OTHER;
			continue;
		}
		/*
		 * This piece of code has been commented out because I have found
		 * valid Postscript files that contain an unbalanced number of '['.
		 * Specifically, this is what was found:
		 *
		 *              81[31 52[28 3[31 19 22 25 31 1[28 31 47 16 2[16 31 28 19 25
		 *
		 * The reason may be that the '[' between numbers has a different
		 * meaning but I could not find such a reference in the
		 * Postscript Language Reference Manual
		 *
		 if ( c == OPEN_BRACKET )
		 {
		 skip_bracket( fd, OPEN_BRACKET, CLOSED_BRACKET ) ;
		 last_token = TOK_OTHER ;
		 continue ;
		 }
		 *
		 */

		if (c == OPEN_CURLY_BRACKET) {
			skip_bracket(fd, OPEN_CURLY_BRACKET, CLOSED_CURLY_BRACKET);
			last_token = TOK_OTHER;
			continue;
		}
		if (c == LESS_THAN) {
			skip_until(fd, GREATER_THAN);
			last_token = TOK_OTHER;
			continue;
		}
		if (c == OPEN_PAREN) {
			decode_string(get_file_char, (void *) &fd);
			output_string = TRUE;
			last_token = TOK_STRING;
			continue;
		}
		if (c == MINUS) {
			/*
			 * Check for a negative number
			 */
			NEXT_CHAR(fd, c);
			if (!isdigit(c)) {
				PUTBACK(fd, c);
				continue;
			}
			num = -get_num(fd, c);
			last_token = TOK_NUMBER;
			continue;
		}
		if (isdigit(c)) {
			num = get_num(fd, c);

			/*
			 * Check if we got 2 number tokens in a row
			 */
			if (last_token == TOK_NUMBER) {
				/*
				 * We got an (x,y) pair denoting the beginning of a line.
				 * Do a line-feed if the last output was a string
				 */
				if (output_string) {
					printout(NEWLINE);
					output_string = FALSE;
				}
			}
			last_token = TOK_NUMBER;
			continue;
		}
		if (isalpha(c)) {
			char letter_buf[16];
			int li = 0;	/* letter buf index */
			int n_letters = 0;

			letter_buf[li++] = c;
			n_letters++;

			for (;;) {
				NEXT_CHAR(fd, c);
				if (c == SIO_EOF)
					break;
				if (!isalnum(c)) {
					PUTBACK(fd, c);
					break;
				}
				letter_buf[li++] = c;
				li %= sizeof(letter_buf);
				n_letters++;
			}

         if (n_letters > 2) {
#ifdef REMOVE_DVI_PLOTS
            extern char *Srdline();
            char *lineptr;
            if (strncmp(letter_buf, "bplot", n_letters) == 0) {
               /*
                * found the beginning of a plot - skip it (else we output
                * lots of lines with nothing by '.' on it)
                */
                for (;;) {
                   lineptr = Srdline(fd);
                   if (lineptr == NULL)
                      break;
	           if (strcmp(lineptr, "eplot") == 0)
                      break;
                }
            }
#endif /* REMOVE_DVI_PLOTS */
            /* ignore others */
            last_token = TOK_OTHER;
            continue;
         }
         /*
          * We have a command: identify it
          */
         switch (letter_buf[0]) {
         case 'l':
         case 'm':
         case 'n':
			case 'o':
			case 'p':
			case 'q':
			case 'r':
			case 's':
			case 't':
				break;	/* command requires no action */

			default:
				if (output_string) {
					int print_space = FALSE;

					switch (last_token) {
					case TOK_NUMBER:
						if (num >= 0)
							print_space = TRUE;
						break;

					case TOK_CMD:
						if (last_cmd != 'p')
							print_space = TRUE;
						break;

					default:
						print_space = TRUE;
					}

					if (print_space) {
						printout(SPACE);
						output_string = FALSE;
					}
				}
			}
			last_cmd = letter_buf[0];
			last_token = TOK_CMD;
		}
	}
}