1 /* $NetBSD: undo.c,v 1.6 2014/03/23 05:06:42 dholland 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 1.6 2014/03/23 05:06:42 dholland 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 undo_t *t;
52
53 #if defined(sun) || defined(NO_REALLOC_NULL)
54 if (ustack == NULL &&
55 (ustack = (undo_t *) malloc((usize = USIZE) * sizeof(undo_t))) == NULL) {
56 fprintf(stderr, "%s\n", strerror(errno));
57 seterrmsg("out of memory");
58 return NULL;
59 }
60 #endif
61 t = ustack;
62 if (u_p < usize ||
63 (t = (undo_t *) realloc(ustack, (usize += USIZE) * sizeof(undo_t))) != NULL) {
64 ustack = t;
65 ustack[u_p].type = type;
66 ustack[u_p].t = get_addressed_line_node(to);
67 ustack[u_p].h = get_addressed_line_node(from);
68 return ustack + u_p++;
69 }
70 /* out of memory - release undo stack */
71 fprintf(stderr, "%s\n", strerror(errno));
72 seterrmsg("out of memory");
73 clear_undo_stack();
74 free(ustack);
75 ustack = NULL;
76 usize = 0;
77 return NULL;
78 }
79
80
81 /* USWAP: swap undo nodes */
82 #define USWAP(x,y) { \
83 undo_t utmp; \
84 utmp = x, x = y, y = utmp; \
85 }
86
87
88 long u_current_addr = -1; /* if >= 0, undo enabled */
89 long u_addr_last = -1; /* if >= 0, undo enabled */
90
91 /* pop_undo_stack: undo last change to the editor buffer */
92 int
pop_undo_stack(void)93 pop_undo_stack(void)
94 {
95 long n;
96 long o_current_addr = current_addr;
97 long o_addr_last = addr_last;
98
99 if (u_current_addr == -1 || u_addr_last == -1) {
100 seterrmsg("nothing to undo");
101 return ERR;
102 } else if (u_p)
103 modified = 1;
104 get_addressed_line_node(0); /* this get_addressed_line_node last! */
105 SPL1();
106 for (n = u_p; n-- > 0;) {
107 switch(ustack[n].type) {
108 case UADD:
109 REQUE(ustack[n].h->q_back, ustack[n].t->q_forw);
110 break;
111 case UDEL:
112 REQUE(ustack[n].h->q_back, ustack[n].h);
113 REQUE(ustack[n].t, ustack[n].t->q_forw);
114 break;
115 case UMOV:
116 case VMOV:
117 REQUE(ustack[n - 1].h, ustack[n].h->q_forw);
118 REQUE(ustack[n].t->q_back, ustack[n - 1].t);
119 REQUE(ustack[n].h, ustack[n].t);
120 n--;
121 break;
122 default:
123 /*NOTREACHED*/
124 ;
125 }
126 ustack[n].type ^= 1;
127 }
128 /* reverse undo stack order */
129 for (n = u_p; n-- > (u_p + 1)/ 2;)
130 USWAP(ustack[n], ustack[u_p - 1 - n]);
131 if (isglobal)
132 clear_active_list();
133 current_addr = u_current_addr, u_current_addr = o_current_addr;
134 addr_last = u_addr_last, u_addr_last = o_addr_last;
135 SPL0();
136 return 0;
137 }
138
139
140 /* clear_undo_stack: clear the undo stack */
141 void
clear_undo_stack(void)142 clear_undo_stack(void)
143 {
144 line_t *lp, *ep, *tl;
145
146 while (u_p--)
147 if (ustack[u_p].type == UDEL) {
148 ep = ustack[u_p].t->q_forw;
149 for (lp = ustack[u_p].h; lp != ep; lp = tl) {
150 unmark_line_node(lp);
151 tl = lp->q_forw;
152 free(lp);
153 }
154 }
155 u_p = 0;
156 u_current_addr = current_addr;
157 u_addr_last = addr_last;
158 }
159