1 /* 2 * Copyright (C) 1984-2009 Mark Nudelman 3 * 4 * You may distribute under the terms of either the GNU General Public 5 * License or the Less License, as specified in the README file. 6 * 7 * For more information about less, or for information on how to 8 * contact the author, see the README file. 9 */ 10 11 12 /* 13 * Routines to perform bracket matching functions. 14 */ 15 16 #include "less.h" 17 #include "position.h" 18 19 /* 20 * Try to match the n-th open bracket 21 * which appears in the top displayed line (forwdir), 22 * or the n-th close bracket 23 * which appears in the bottom displayed line (!forwdir). 24 * The characters which serve as "open bracket" and 25 * "close bracket" are given. 26 */ 27 public void 28 match_brac(obrac, cbrac, forwdir, n) 29 register int obrac; 30 register int cbrac; 31 int forwdir; 32 int n; 33 { 34 register int c; 35 register int nest; 36 POSITION pos; 37 int (*chget)(); 38 39 extern int ch_forw_get(), ch_back_get(); 40 41 /* 42 * Seek to the line containing the open bracket. 43 * This is either the top or bottom line on the screen, 44 * depending on the type of bracket. 45 */ 46 pos = position((forwdir) ? TOP : BOTTOM); 47 if (pos == NULL_POSITION || ch_seek(pos)) 48 { 49 if (forwdir) 50 error("Nothing in top line", NULL_PARG); 51 else 52 error("Nothing in bottom line", NULL_PARG); 53 return; 54 } 55 56 /* 57 * Look thru the line to find the open bracket to match. 58 */ 59 do 60 { 61 if ((c = ch_forw_get()) == '\n' || c == EOI) 62 { 63 if (forwdir) 64 error("No bracket in top line", NULL_PARG); 65 else 66 error("No bracket in bottom line", NULL_PARG); 67 return; 68 } 69 } while (c != obrac || --n > 0); 70 71 /* 72 * Position the file just "after" the open bracket 73 * (in the direction in which we will be searching). 74 * If searching forward, we are already after the bracket. 75 * If searching backward, skip back over the open bracket. 76 */ 77 if (!forwdir) 78 (void) ch_back_get(); 79 80 /* 81 * Search the file for the matching bracket. 82 */ 83 chget = (forwdir) ? ch_forw_get : ch_back_get; 84 nest = 0; 85 while ((c = (*chget)()) != EOI) 86 { 87 if (c == obrac) 88 nest++; 89 else if (c == cbrac && --nest < 0) 90 { 91 /* 92 * Found the matching bracket. 93 * If searching backward, put it on the top line. 94 * If searching forward, put it on the bottom line. 95 */ 96 jump_line_loc(ch_tell(), forwdir ? -1 : 1); 97 return; 98 } 99 } 100 error("No matching bracket", NULL_PARG); 101 } 102