1/*
2 * Copyright (C) 1984-2023  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, see the README file.
8 */
9
10
11/*
12 * Routines to perform bracket matching functions.
13 */
14
15#include "less.h"
16#include "position.h"
17
18/*
19 * Try to match the n-th open bracket
20 *  which appears in the top displayed line (forwdir),
21 * or the n-th close bracket
22 *  which appears in the bottom displayed line (!forwdir).
23 * The characters which serve as "open bracket" and
24 * "close bracket" are given.
25 */
26public void match_brac(char obrac, char cbrac, int forwdir, int n)
27{
28	int c;
29	int nest;
30	POSITION pos;
31	int (*chget)();
32
33	extern int ch_forw_get(), ch_back_get();
34
35	/*
36	 * Seek to the line containing the open bracket.
37	 * This is either the top or bottom line on the screen,
38	 * depending on the type of bracket.
39	 */
40	pos = position((forwdir) ? TOP : BOTTOM);
41	if (pos == NULL_POSITION || ch_seek(pos))
42	{
43		if (forwdir)
44			error("Nothing in top line", NULL_PARG);
45		else
46			error("Nothing in bottom line", NULL_PARG);
47		return;
48	}
49
50	/*
51	 * Look thru the line to find the open bracket to match.
52	 */
53	do
54	{
55		if ((c = ch_forw_get()) == '\n' || c == EOI)
56		{
57			if (forwdir)
58				error("No bracket in top line", NULL_PARG);
59			else
60				error("No bracket in bottom line", NULL_PARG);
61			return;
62		}
63	} while (c != obrac || --n > 0);
64
65	/*
66	 * Position the file just "after" the open bracket
67	 * (in the direction in which we will be searching).
68	 * If searching forward, we are already after the bracket.
69	 * If searching backward, skip back over the open bracket.
70	 */
71	if (!forwdir)
72		(void) ch_back_get();
73
74	/*
75	 * Search the file for the matching bracket.
76	 */
77	chget = (forwdir) ? ch_forw_get : ch_back_get;
78	nest = 0;
79	while ((c = (*chget)()) != EOI)
80	{
81		if (c == obrac)
82		{
83			if (nest == INT_MAX)
84				break;
85			nest++;
86		}
87		else if (c == cbrac && --nest < 0)
88		{
89			/*
90			 * Found the matching bracket.
91			 * If searching backward, put it on the top line.
92			 * If searching forward, put it on the bottom line.
93			 */
94			jump_line_loc(ch_tell(), forwdir ? -1 : 1);
95			return;
96		}
97	}
98	error("No matching bracket", NULL_PARG);
99}
100