1 /* undo.c: This file contains the undo routines for the ed line editor */
3 * Copyright (c) 1993 Andrew Moore, Talke Studio.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * @(#)undo.c,v 1.1 1994/02/01 00:34:44 alm Exp
28 * $FreeBSD: src/bin/ed/undo.c,v 1.9 1999/08/27 23:14:15 peter Exp $
29 * $DragonFly: src/bin/ed/undo.c,v 1.2 2003/06/17 04:22:50 dillon Exp $
35 #define USIZE 100 /* undo stack size */
36 undo_t *ustack = NULL; /* undo stack */
37 long usize = 0; /* stack size variable */
38 long u_p = 0; /* undo stack pointer */
40 /* push_undo_stack: return pointer to initialized undo node */
42 push_undo_stack(type, from, to)
49 #if defined(sun) || defined(NO_REALLOC_NULL)
51 (ustack = (undo_t *) malloc((usize = USIZE) * sizeof(undo_t))) == NULL) {
52 fprintf(stderr, "%s\n", strerror(errno));
53 sprintf(errmsg, "out of memory");
59 (t = (undo_t *) realloc(ustack, (usize += USIZE) * sizeof(undo_t))) != NULL) {
61 ustack[u_p].type = type;
62 ustack[u_p].t = get_addressed_line_node(to);
63 ustack[u_p].h = get_addressed_line_node(from);
64 return ustack + u_p++;
66 /* out of memory - release undo stack */
67 fprintf(stderr, "%s\n", strerror(errno));
68 sprintf(errmsg, "out of memory");
77 /* USWAP: swap undo nodes */
78 #define USWAP(x,y) { \
80 utmp = x, x = y, y = utmp; \
84 long u_current_addr = -1; /* if >= 0, undo enabled */
85 long u_addr_last = -1; /* if >= 0, undo enabled */
87 /* pop_undo_stack: undo last change to the editor buffer */
92 long o_current_addr = current_addr;
93 long o_addr_last = addr_last;
95 if (u_current_addr == -1 || u_addr_last == -1) {
96 sprintf(errmsg, "nothing to undo");
100 get_addressed_line_node(0); /* this get_addressed_line_node last! */
102 for (n = u_p; n-- > 0;) {
103 switch(ustack[n].type) {
105 REQUE(ustack[n].h->q_back, ustack[n].t->q_forw);
108 REQUE(ustack[n].h->q_back, ustack[n].h);
109 REQUE(ustack[n].t, ustack[n].t->q_forw);
113 REQUE(ustack[n - 1].h, ustack[n].h->q_forw);
114 REQUE(ustack[n].t->q_back, ustack[n - 1].t);
115 REQUE(ustack[n].h, ustack[n].t);
124 /* reverse undo stack order */
125 for (n = u_p; n-- > (u_p + 1)/ 2;)
126 USWAP(ustack[n], ustack[u_p - 1 - n]);
129 current_addr = u_current_addr, u_current_addr = o_current_addr;
130 addr_last = u_addr_last, u_addr_last = o_addr_last;
136 /* clear_undo_stack: clear the undo stack */
140 line_t *lp, *ep, *tl;
143 if (ustack[u_p].type == UDEL) {
144 ep = ustack[u_p].t->q_forw;
145 for (lp = ustack[u_p].h; lp != ep; lp = tl) {
146 unmark_line_node(lp);
152 u_current_addr = current_addr;
153 u_addr_last = addr_last;