1 /*- 2 * Copyright (c) 1992, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #ifndef lint 9 static char sccsid[] = "@(#)tscroll.c 8.3 (Berkeley) 05/04/94"; 10 #endif /* not lint */ 11 12 #include "curses.h" 13 14 #define MAXRETURNSIZE 64 15 16 /* 17 * Routine to perform scrolling. Derived from tgoto.c in tercamp(3) 18 * library. Cap is a string containing printf type escapes to allow 19 * scrolling. The following escapes are defined for substituting n: 20 * 21 * %d as in printf 22 * %2 like %2d 23 * %3 like %3d 24 * %. gives %c hacking special case characters 25 * %+x like %c but adding x first 26 * 27 * The codes below affect the state but don't use up a value. 28 * 29 * %>xy if value > x add y 30 * %i increments n 31 * %% gives % 32 * %B BCD (2 decimal digits encoded in one byte) 33 * %D Delta Data (backwards bcd) 34 * 35 * all other characters are ``self-inserting''. 36 */ 37 char * 38 __tscroll(cap, n) 39 const char *cap; 40 int n; 41 { 42 static char result[MAXRETURNSIZE]; 43 int c; 44 char *dp; 45 46 if (cap == NULL) 47 goto err; 48 for (dp = result; (c = *cap++) != '\0';) { 49 if (c != '%') { 50 *dp++ = c; 51 continue; 52 } 53 switch (c = *cap++) { 54 case 'n': 55 n ^= 0140; 56 continue; 57 case 'd': 58 if (n < 10) 59 goto one; 60 if (n < 100) 61 goto two; 62 /* FALLTHROUGH */ 63 case '3': 64 *dp++ = (n / 100) | '0'; 65 n %= 100; 66 /* FALLTHROUGH */ 67 case '2': 68 two: *dp++ = n / 10 | '0'; 69 one: *dp++ = n % 10 | '0'; 70 continue; 71 case '>': 72 if (n > *cap++) 73 n += *cap++; 74 else 75 cap++; 76 continue; 77 case '+': 78 n += *cap++; 79 /* FALLTHROUGH */ 80 case '.': 81 *dp++ = n; 82 continue; 83 case 'i': 84 n++; 85 continue; 86 case '%': 87 *dp++ = c; 88 continue; 89 case 'B': 90 n = (n / 10 << 4) + n % 10; 91 continue; 92 case 'D': 93 n = n - 2 * (n % 16); 94 continue; 95 /* 96 * XXX 97 * System V terminfo files have lots of extra gunk. 98 * The only one we've seen in scrolling strings is 99 * %pN, and it seems to work okay if we ignore it. 100 */ 101 case 'p': 102 ++cap; 103 continue; 104 default: 105 goto err; 106 } 107 } 108 *dp = '\0'; 109 return (result); 110 111 err: return("curses: __tscroll failed"); 112 } 113