Return to brac.c CVS log

Up to [local] / src / usr.bin / less

Annotation of src/usr.bin/less/brac.c, Revision 1.6

1.1       etheisen    1: /*
1.6     ! shadchin    2:  * Copyright (C) 1984-2012  Mark Nudelman
1.1       etheisen    3:  *
1.4       millert     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.
1.1       etheisen    6:  *
1.6     ! shadchin    7:  * For more information, see the README file.
1.1       etheisen    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:  */
                     26:        public void
                     27: match_brac(obrac, cbrac, forwdir, n)
1.4       millert    28:        register int obrac;
                     29:        register int cbrac;
1.1       etheisen   30:        int forwdir;
                     31:        int n;
                     32: {
1.4       millert    33:        register int c;
                     34:        register int nest;
1.1       etheisen   35:        POSITION pos;
                     36:        int (*chget)();
                     37:
                     38:        extern int ch_forw_get(), ch_back_get();
                     39:
                     40:        /*
                     41:         * Seek to the line containing the open bracket.
                     42:         * This is either the top or bottom line on the screen,
                     43:         * depending on the type of bracket.
                     44:         */
                     45:        pos = position((forwdir) ? TOP : BOTTOM);
                     46:        if (pos == NULL_POSITION || ch_seek(pos))
                     47:        {
                     48:                if (forwdir)
                     49:                        error("Nothing in top line", NULL_PARG);
                     50:                else
                     51:                        error("Nothing in bottom line", NULL_PARG);
                     52:                return;
                     53:        }
                     54:
                     55:        /*
                     56:         * Look thru the line to find the open bracket to match.
                     57:         */
                     58:        do
                     59:        {
                     60:                if ((c = ch_forw_get()) == '\n' || c == EOI)
                     61:                {
                     62:                        if (forwdir)
                     63:                                error("No bracket in top line", NULL_PARG);
                     64:                        else
                     65:                                error("No bracket in bottom line", NULL_PARG);
                     66:                        return;
                     67:                }
                     68:        } while (c != obrac || --n > 0);
                     69:
                     70:        /*
                     71:         * Position the file just "after" the open bracket
                     72:         * (in the direction in which we will be searching).
                     73:         * If searching forward, we are already after the bracket.
                     74:         * If searching backward, skip back over the open bracket.
                     75:         */
                     76:        if (!forwdir)
                     77:                (void) ch_back_get();
                     78:
                     79:        /*
                     80:         * Search the file for the matching bracket.
                     81:         */
                     82:        chget = (forwdir) ? ch_forw_get : ch_back_get;
                     83:        nest = 0;
                     84:        while ((c = (*chget)()) != EOI)
                     85:        {
                     86:                if (c == obrac)
                     87:                        nest++;
                     88:                else if (c == cbrac && --nest < 0)
                     89:                {
                     90:                        /*
                     91:                         * Found the matching bracket.
                     92:                         * If searching backward, put it on the top line.
                     93:                         * If searching forward, put it on the bottom line.
                     94:                         */
                     95:                        jump_line_loc(ch_tell(), forwdir ? -1 : 1);
                     96:                        return;
                     97:                }
                     98:        }
                     99:        error("No matching bracket", NULL_PARG);
                    100: }