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tscroll.c revision 1.3 
      1 /*-
      2  * Copyright (c) 1992, 1993, 1994
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 static char sccsid[] = "@(#)tscroll.c	8.4 (Berkeley) 7/27/94";
     36 #endif /* not lint */
     37 
     38 #include "curses.h"
     39 
     40 #define	MAXRETURNSIZE	64
     41 
     42 /*
     43  * Routine to perform scrolling.  Derived from tgoto.c in tercamp(3)
     44  * library.  Cap is a string containing printf type escapes to allow
     45  * scrolling.  The following escapes are defined for substituting n:
     46  *
     47  *	%d	as in printf
     48  *	%2	like %2d
     49  *	%3	like %3d
     50  *	%.	gives %c hacking special case characters
     51  *	%+x	like %c but adding x first
     52  *
     53  *	The codes below affect the state but don't use up a value.
     54  *
     55  *	%>xy	if value > x add y
     56  *	%i	increments n
     57  *	%%	gives %
     58  *	%B	BCD (2 decimal digits encoded in one byte)
     59  *	%D	Delta Data (backwards bcd)
     60  *
     61  * all other characters are ``self-inserting''.
     62  */
     63 char *
     64 __tscroll(cap, n1, n2)
     65 	const char *cap;
     66 	int n1, n2;
     67 {
     68 	static char result[MAXRETURNSIZE];
     69 	int c, n;
     70 	char *dp;
     71 
     72 	if (cap == NULL)
     73 		goto err;
     74 	for (n = n1, dp = result; (c = *cap++) != '\0';) {
     75 		if (c != '%') {
     76 			*dp++ = c;
     77 			continue;
     78 		}
     79 		switch (c = *cap++) {
     80 		case 'n':
     81 			n ^= 0140;
     82 			continue;
     83 		case 'd':
     84 			if (n < 10)
     85 				goto one;
     86 			if (n < 100)
     87 				goto two;
     88 			/* FALLTHROUGH */
     89 		case '3':
     90 			*dp++ = (n / 100) | '0';
     91 			n %= 100;
     92 			/* FALLTHROUGH */
     93 		case '2':
     94 two:			*dp++ = n / 10 | '0';
     95 one:			*dp++ = n % 10 | '0';
     96 			n = n2;
     97 			continue;
     98 		case '>':
     99 			if (n > *cap++)
    100 				n += *cap++;
    101 			else
    102 				cap++;
    103 			continue;
    104 		case '+':
    105 			n += *cap++;
    106 			/* FALLTHROUGH */
    107 		case '.':
    108 			*dp++ = n;
    109 			continue;
    110 		case 'i':
    111 			n++;
    112 			continue;
    113 		case '%':
    114 			*dp++ = c;
    115 			continue;
    116 		case 'B':
    117 			n = (n / 10 << 4) + n % 10;
    118 			continue;
    119 		case 'D':
    120 			n = n - 2 * (n % 16);
    121 			continue;
    122 		/*
    123 		 * XXX
    124 		 * System V terminfo files have lots of extra gunk.
    125 		 * The only one we've seen in scrolling strings is
    126 		 * %pN, and it seems to work okay if we ignore it.
    127 		 */
    128 		case 'p':
    129 			++cap;
    130 			continue;
    131 		default:
    132 			goto err;
    133 		}
    134 	}
    135 	*dp = '\0';
    136 	return (result);
    137 
    138 err:	return("curses: __tscroll failed");
    139 }
    140