1 /* $OpenBSD: undo.c,v 1.14 2016/03/22 17:58:28 mmcc Exp $ */
2 /* $NetBSD: undo.c,v 1.2 1995/03/21 09:04:52 cgd Exp $ */
3
4 /* undo.c: This file contains the undo routines for the ed line editor */
5 /*-
6 * Copyright (c) 1993 Andrew Moore, Talke Studio.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <regex.h>
32 #include <signal.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35
36 #include "ed.h"
37
38 #define USIZE 100 /* undo stack size */
39 static undo_t *ustack = NULL; /* undo stack */
40 static int usize = 0; /* stack size variable */
41 static int u_p = 0; /* undo stack pointer */
42
43 /* push_undo_stack: return pointer to initialized undo node */
44 undo_t *
push_undo_stack(int type,int from,int to)45 push_undo_stack(int type, int from, int to)
46 {
47 undo_t *t;
48
49 t = ustack;
50 if (u_p < usize ||
51 (t = reallocarray(ustack, (usize += USIZE), sizeof(undo_t))) != NULL) {
52 ustack = t;
53 ustack[u_p].type = type;
54 ustack[u_p].t = get_addressed_line_node(to);
55 ustack[u_p].h = get_addressed_line_node(from);
56 return ustack + u_p++;
57 }
58 /* out of memory - release undo stack */
59 perror(NULL);
60 seterrmsg("out of memory");
61 clear_undo_stack();
62 free(ustack);
63 ustack = NULL;
64 usize = 0;
65 return NULL;
66 }
67
68
69 /* USWAP: swap undo nodes */
70 #define USWAP(x,y) { \
71 undo_t utmp; \
72 utmp = x, x = y, y = utmp; \
73 }
74
75
76 int u_current_addr = -1; /* if >= 0, undo enabled */
77 int u_addr_last = -1; /* if >= 0, undo enabled */
78
79 /* pop_undo_stack: undo last change to the editor buffer */
80 int
pop_undo_stack(void)81 pop_undo_stack(void)
82 {
83 int n;
84 int o_current_addr = current_addr;
85 int o_addr_last = addr_last;
86
87 if (u_current_addr == -1 || u_addr_last == -1) {
88 seterrmsg("nothing to undo");
89 return ERR;
90 } else if (u_p)
91 modified = 1;
92 get_addressed_line_node(0); /* this get_addressed_line_node last! */
93 SPL1();
94 for (n = u_p; n-- > 0;) {
95 switch(ustack[n].type) {
96 case UADD:
97 REQUE(ustack[n].h->q_back, ustack[n].t->q_forw);
98 break;
99 case UDEL:
100 REQUE(ustack[n].h->q_back, ustack[n].h);
101 REQUE(ustack[n].t, ustack[n].t->q_forw);
102 break;
103 case UMOV:
104 case VMOV:
105 REQUE(ustack[n - 1].h, ustack[n].h->q_forw);
106 REQUE(ustack[n].t->q_back, ustack[n - 1].t);
107 REQUE(ustack[n].h, ustack[n].t);
108 n--;
109 break;
110 default:
111 /*NOTREACHED*/
112 ;
113 }
114 ustack[n].type ^= 1;
115 }
116 /* reverse undo stack order */
117 for (n = u_p; n-- > (u_p + 1)/ 2;)
118 USWAP(ustack[n], ustack[u_p - 1 - n]);
119 if (isglobal)
120 clear_active_list();
121 current_addr = u_current_addr, u_current_addr = o_current_addr;
122 addr_last = u_addr_last, u_addr_last = o_addr_last;
123 SPL0();
124 return 0;
125 }
126
127
128 /* clear_undo_stack: clear the undo stack */
129 void
clear_undo_stack(void)130 clear_undo_stack(void)
131 {
132 line_t *lp, *ep, *tl;
133
134 while (u_p--)
135 if (ustack[u_p].type == UDEL) {
136 ep = ustack[u_p].t->q_forw;
137 for (lp = ustack[u_p].h; lp != ep; lp = tl) {
138 unmark_line_node(lp);
139 tl = lp->q_forw;
140 free(lp);
141 }
142 }
143 u_p = 0;
144 u_current_addr = current_addr;
145 u_addr_last = addr_last;
146 }
147