gno/bin/less/brac.c
gdr-ftp 784e3de7cd Initial checkin of aroff, binprint, center, less, ls, make, makemake,
passwd, ps, purge, shutdown, stty, upper, and vi.  These sources are
for the versions of the utils shipped with GNO v2.0.4.
1998-03-09 08:30:21 +00:00

95 lines
2.1 KiB
C

/*
* Routines to perform bracket matching functions.
*/
#pragma noroot
#include "less.h"
#include "position.h"
#ifdef _ORCAC_
segment "LoadSegONE";
#endif
/*
* 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 ((c = ch_forw_get()) == '\r' || 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);
}