Annotation of src/usr.bin/less/brac.c, Revision 1.1.1.1
1.1 etheisen 1: /*
2: * Copyright (c) 1984,1985,1989,1994,1995 Mark Nudelman
3: * 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 in the documentation and/or other materials provided with
12: * the distribution.
13: *
14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
15: * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
18: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
19: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
20: * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
21: * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22: * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
23: * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
24: * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25: */
26:
27:
28: /*
29: * Routines to perform bracket matching functions.
30: */
31:
32: #include "less.h"
33: #include "position.h"
34:
35: /*
36: * Try to match the n-th open bracket
37: * which appears in the top displayed line (forwdir),
38: * or the n-th close bracket
39: * which appears in the bottom displayed line (!forwdir).
40: * The characters which serve as "open bracket" and
41: * "close bracket" are given.
42: */
43: public void
44: match_brac(obrac, cbrac, forwdir, n)
45: register int obrac;
46: register int cbrac;
47: int forwdir;
48: int n;
49: {
50: register int c;
51: register int nest;
52: POSITION pos;
53: int (*chget)();
54:
55: extern int ch_forw_get(), ch_back_get();
56:
57: /*
58: * Seek to the line containing the open bracket.
59: * This is either the top or bottom line on the screen,
60: * depending on the type of bracket.
61: */
62: pos = position((forwdir) ? TOP : BOTTOM);
63: if (pos == NULL_POSITION || ch_seek(pos))
64: {
65: if (forwdir)
66: error("Nothing in top line", NULL_PARG);
67: else
68: error("Nothing in bottom line", NULL_PARG);
69: return;
70: }
71:
72: /*
73: * Look thru the line to find the open bracket to match.
74: */
75: do
76: {
77: if ((c = ch_forw_get()) == '\n' || c == EOI)
78: {
79: if (forwdir)
80: error("No bracket in top line", NULL_PARG);
81: else
82: error("No bracket in bottom line", NULL_PARG);
83: return;
84: }
85: } while (c != obrac || --n > 0);
86:
87: /*
88: * Position the file just "after" the open bracket
89: * (in the direction in which we will be searching).
90: * If searching forward, we are already after the bracket.
91: * If searching backward, skip back over the open bracket.
92: */
93: if (!forwdir)
94: (void) ch_back_get();
95:
96: /*
97: * Search the file for the matching bracket.
98: */
99: chget = (forwdir) ? ch_forw_get : ch_back_get;
100: nest = 0;
101: while ((c = (*chget)()) != EOI)
102: {
103: if (c == obrac)
104: nest++;
105: else if (c == cbrac && --nest < 0)
106: {
107: /*
108: * Found the matching bracket.
109: * If searching backward, put it on the top line.
110: * If searching forward, put it on the bottom line.
111: */
112: jump_line_loc(ch_tell(), forwdir ? -1 : 1);
113: return;
114: }
115: }
116: error("No matching bracket", NULL_PARG);
117: }