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/*
* Copyright (C) 1984-2004 Mark Nudelman
*
* You may distribute under the terms of either the GNU General Public
* License or the Less License, as specified in the README file.
*
* For more information about less, or for information on how to
* contact the author, see the README file.
*/
/*
* Routines to perform bracket matching functions.
*/
#include "less.h"
#include "position.h"
/*
* Try to match the n-th open bracket
* which appears in the top displayed line (forwdir),
* or the n-th close bracket
* which appears in the bottom displayed line (!forwdir).
* The characters which serve as "open bracket" and
* "close bracket" are given.
*/
public void
match_brac(obrac, cbrac, forwdir, n)
register int obrac;
register int cbrac;
int forwdir;
int n;
{
register int c;
register int nest;
POSITION pos;
int (*chget)();
extern int ch_forw_get(), ch_back_get();
/*
* Seek to the line containing the open bracket.
* This is either the top or bottom line on the screen,
* depending on the type of bracket.
*/
pos = position((forwdir) ? TOP : BOTTOM);
if (pos == NULL_POSITION || ch_seek(pos))
{
if (forwdir)
error("Nothing in top line", NULL_PARG);
else
error("Nothing in bottom line", NULL_PARG);
return;
}
/*
* Look thru the line to find the open bracket to match.
*/
do
{
if ((c = ch_forw_get()) == '\n' || c == EOI)
{
if (forwdir)
error("No bracket in top line", NULL_PARG);
else
error("No bracket in bottom line", NULL_PARG);
return;
}
} while (c != obrac || --n > 0);
/*
* Position the file just "after" the open bracket
* (in the direction in which we will be searching).
* If searching forward, we are already after the bracket.
* If searching backward, skip back over the open bracket.
*/
if (!forwdir)
(void) ch_back_get();
/*
* Search the file for the matching bracket.
*/
chget = (forwdir) ? ch_forw_get : ch_back_get;
nest = 0;
while ((c = (*chget)()) != EOI)
{
if (c == obrac)
nest++;
else if (c == cbrac && --nest < 0)
{
/*
* Found the matching bracket.
* If searching backward, put it on the top line.
* If searching forward, put it on the bottom line.
*/
jump_line_loc(ch_tell(), forwdir ? -1 : 1);
return;
}
}
error("No matching bracket", NULL_PARG);
}
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