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Annotation of src/usr.bin/less/brac.c, Revision 1.1.1.3

1.1       etheisen    1: /*
1.1.1.3 ! shadchin    2:  * Copyright (C) 1984-2011  Mark Nudelman
1.1       etheisen    3:  *
1.1.1.2   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:  *
1.1.1.2   millert     7:  * For more information about less, or for information on how to
                      8:  * contact the author, see the README file.
1.1       etheisen    9:  */
                     10:
                     11:
                     12: /*
                     13:  * Routines to perform bracket matching functions.
                     14:  */
                     15:
                     16: #include "less.h"
                     17: #include "position.h"
                     18:
                     19: /*
                     20:  * Try to match the n-th open bracket
                     21:  *  which appears in the top displayed line (forwdir),
                     22:  * or the n-th close bracket
                     23:  *  which appears in the bottom displayed line (!forwdir).
                     24:  * The characters which serve as "open bracket" and
                     25:  * "close bracket" are given.
                     26:  */
                     27:        public void
                     28: match_brac(obrac, cbrac, forwdir, n)
                     29:        register int obrac;
                     30:        register int cbrac;
                     31:        int forwdir;
                     32:        int n;
                     33: {
                     34:        register int c;
                     35:        register int nest;
                     36:        POSITION pos;
                     37:        int (*chget)();
                     38:
                     39:        extern int ch_forw_get(), ch_back_get();
                     40:
                     41:        /*
                     42:         * Seek to the line containing the open bracket.
                     43:         * This is either the top or bottom line on the screen,
                     44:         * depending on the type of bracket.
                     45:         */
                     46:        pos = position((forwdir) ? TOP : BOTTOM);
                     47:        if (pos == NULL_POSITION || ch_seek(pos))
                     48:        {
                     49:                if (forwdir)
                     50:                        error("Nothing in top line", NULL_PARG);
                     51:                else
                     52:                        error("Nothing in bottom line", NULL_PARG);
                     53:                return;
                     54:        }
                     55:
                     56:        /*
                     57:         * Look thru the line to find the open bracket to match.
                     58:         */
                     59:        do
                     60:        {
                     61:                if ((c = ch_forw_get()) == '\n' || c == EOI)
                     62:                {
                     63:                        if (forwdir)
                     64:                                error("No bracket in top line", NULL_PARG);
                     65:                        else
                     66:                                error("No bracket in bottom line", NULL_PARG);
                     67:                        return;
                     68:                }
                     69:        } while (c != obrac || --n > 0);
                     70:
                     71:        /*
                     72:         * Position the file just "after" the open bracket
                     73:         * (in the direction in which we will be searching).
                     74:         * If searching forward, we are already after the bracket.
                     75:         * If searching backward, skip back over the open bracket.
                     76:         */
                     77:        if (!forwdir)
                     78:                (void) ch_back_get();
                     79:
                     80:        /*
                     81:         * Search the file for the matching bracket.
                     82:         */
                     83:        chget = (forwdir) ? ch_forw_get : ch_back_get;
                     84:        nest = 0;
                     85:        while ((c = (*chget)()) != EOI)
                     86:        {
                     87:                if (c == obrac)
                     88:                        nest++;
                     89:                else if (c == cbrac && --nest < 0)
                     90:                {
                     91:                        /*
                     92:                         * Found the matching bracket.
                     93:                         * If searching backward, put it on the top line.
                     94:                         * If searching forward, put it on the bottom line.
                     95:                         */
                     96:                        jump_line_loc(ch_tell(), forwdir ? -1 : 1);
                     97:                        return;
                     98:                }
                     99:        }
                    100:        error("No matching bracket", NULL_PARG);
                    101: }