1 /* $NetBSD: undo.c,v 1.8 2021/11/02 08:04:20 nia Exp $ */
2
3 /* undo.c: This file contains the undo routines for the ed line editor */
4 /*-
5 * Copyright (c) 1993 Andrew Moore, Talke Studio.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
31 #ifndef lint
32 #if 0
33 static char *rcsid = "@(#)undo.c,v 1.1 1994/02/01 00:34:44 alm Exp";
34 #else
35 __RCSID("$NetBSD: undo.c,v 1.8 2021/11/02 08:04:20 nia Exp $");
36 #endif
37 #endif /* not lint */
38
39 #include "ed.h"
40
41
42 #define USIZE 100 /* undo stack size */
43 undo_t *ustack = NULL; /* undo stack */
44 long usize = 0; /* stack size variable */
45 long u_p = 0; /* undo stack pointer */
46
47 /* push_undo_stack: return pointer to initialized undo node */
48 undo_t *
push_undo_stack(int type,long from,long to)49 push_undo_stack(int type, long from, long to)
50 {
51 int err;
52
53 if (u_p < usize ||
54 (err = reallocarr(&ustack, usize += USIZE, sizeof(undo_t))) == 0) {
55 ustack[u_p].type = type;
56 ustack[u_p].t = get_addressed_line_node(to);
57 ustack[u_p].h = get_addressed_line_node(from);
58 return ustack + u_p++;
59 }
60 /* out of memory - release undo stack */
61 fprintf(stderr, "%s\n", strerror(err));
62 seterrmsg("out of memory");
63 clear_undo_stack();
64 free(ustack);
65 ustack = NULL;
66 usize = 0;
67 return NULL;
68 }
69
70
71 /* USWAP: swap undo nodes */
72 #define USWAP(x,y) { \
73 undo_t utmp; \
74 utmp = x, x = y, y = utmp; \
75 }
76
77
78 long u_current_addr = -1; /* if >= 0, undo enabled */
79 long u_addr_last = -1; /* if >= 0, undo enabled */
80
81 /* pop_undo_stack: undo last change to the editor buffer */
82 int
pop_undo_stack(void)83 pop_undo_stack(void)
84 {
85 long n;
86 long o_current_addr = current_addr;
87 long o_addr_last = addr_last;
88
89 if (u_current_addr == -1 || u_addr_last == -1) {
90 seterrmsg("nothing to undo");
91 return ERR;
92 } else if (u_p)
93 modified = 1;
94 get_addressed_line_node(0); /* this get_addressed_line_node last! */
95 SPL1();
96 for (n = u_p; n-- > 0;) {
97 switch(ustack[n].type) {
98 case UADD:
99 REQUE(ustack[n].h->q_back, ustack[n].t->q_forw);
100 break;
101 case UDEL:
102 REQUE(ustack[n].h->q_back, ustack[n].h);
103 REQUE(ustack[n].t, ustack[n].t->q_forw);
104 break;
105 case UMOV:
106 case VMOV:
107 REQUE(ustack[n - 1].h, ustack[n].h->q_forw);
108 REQUE(ustack[n].t->q_back, ustack[n - 1].t);
109 REQUE(ustack[n].h, ustack[n].t);
110 n--;
111 break;
112 default:
113 /*NOTREACHED*/
114 ;
115 }
116 ustack[n].type ^= 1;
117 }
118 /* reverse undo stack order */
119 for (n = u_p; n-- > (u_p + 1)/ 2;)
120 USWAP(ustack[n], ustack[u_p - 1 - n]);
121 if (isglobal)
122 clear_active_list();
123 current_addr = u_current_addr, u_current_addr = o_current_addr;
124 addr_last = u_addr_last, u_addr_last = o_addr_last;
125 SPL0();
126 return 0;
127 }
128
129
130 /* clear_undo_stack: clear the undo stack */
131 void
clear_undo_stack(void)132 clear_undo_stack(void)
133 {
134 line_t *lp, *ep, *tl;
135
136 while (u_p--)
137 if (ustack[u_p].type == UDEL) {
138 ep = ustack[u_p].t->q_forw;
139 for (lp = ustack[u_p].h; lp != ep; lp = tl) {
140 unmark_line_node(lp);
141 tl = lp->q_forw;
142 free(lp);
143 }
144 }
145 u_p = 0;
146 u_current_addr = current_addr;
147 u_addr_last = addr_last;
148 }
149