1 /* undo.c: This file contains the undo routines for the ed line editor */
2 /*-
3 * Copyright (c) 1993 Andrew Moore, Talke Studio.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
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.
14 *
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
25 * SUCH DAMAGE.
26 *
27 * @(#)undo.c,v 1.1 1994/02/01 00:34:44 alm Exp
28 * $FreeBSD: head/bin/ed/undo.c 241720 2012-10-19 05:43:38Z ed $
29 */
30
31 #include "ed.h"
32
33
34 #define USIZE 100 /* undo stack size */
35 static undo_t *ustack = NULL; /* undo stack */
36 static long usize = 0; /* stack size variable */
37 static long u_p = 0; /* undo stack pointer */
38
39 /* push_undo_stack: return pointer to initialized undo node */
40 undo_t *
push_undo_stack(int type,long from,long to)41 push_undo_stack(int type, long from, long to)
42 {
43 undo_t *t;
44
45 #if defined(sun) || defined(NO_REALLOC_NULL)
46 if (ustack == NULL &&
47 (ustack = (undo_t *) malloc((usize = USIZE) * sizeof(undo_t))) == NULL) {
48 fprintf(stderr, "%s\n", strerror(errno));
49 errmsg = "out of memory";
50 return NULL;
51 }
52 #endif
53 t = ustack;
54 if (u_p < usize ||
55 (t = (undo_t *) realloc(ustack, (usize += USIZE) * sizeof(undo_t))) != NULL) {
56 ustack = t;
57 ustack[u_p].type = type;
58 ustack[u_p].t = get_addressed_line_node(to);
59 ustack[u_p].h = get_addressed_line_node(from);
60 return ustack + u_p++;
61 }
62 /* out of memory - release undo stack */
63 fprintf(stderr, "%s\n", strerror(errno));
64 errmsg = "out of memory";
65 clear_undo_stack();
66 free(ustack);
67 ustack = NULL;
68 usize = 0;
69 return NULL;
70 }
71
72
73 /* USWAP: swap undo nodes */
74 #define USWAP(x,y) { \
75 undo_t utmp; \
76 utmp = x, x = y, y = utmp; \
77 }
78
79
80 long u_current_addr = -1; /* if >= 0, undo enabled */
81 long u_addr_last = -1; /* if >= 0, undo enabled */
82
83 /* pop_undo_stack: undo last change to the editor buffer */
84 int
pop_undo_stack(void)85 pop_undo_stack(void)
86 {
87 long n;
88 long o_current_addr = current_addr;
89 long o_addr_last = addr_last;
90
91 if (u_current_addr == -1 || u_addr_last == -1) {
92 errmsg = "nothing to undo";
93 return ERR;
94 } else if (u_p)
95 modified = 1;
96 get_addressed_line_node(0); /* this get_addressed_line_node last! */
97 SPL1();
98 for (n = u_p; n-- > 0;) {
99 switch(ustack[n].type) {
100 case UADD:
101 REQUE(ustack[n].h->q_back, ustack[n].t->q_forw);
102 break;
103 case UDEL:
104 REQUE(ustack[n].h->q_back, ustack[n].h);
105 REQUE(ustack[n].t, ustack[n].t->q_forw);
106 break;
107 case UMOV:
108 case VMOV:
109 REQUE(ustack[n - 1].h, ustack[n].h->q_forw);
110 REQUE(ustack[n].t->q_back, ustack[n - 1].t);
111 REQUE(ustack[n].h, ustack[n].t);
112 n--;
113 break;
114 default:
115 /*NOTREACHED*/
116 ;
117 }
118 ustack[n].type ^= 1;
119 }
120 /* reverse undo stack order */
121 for (n = u_p; n-- > (u_p + 1)/ 2;)
122 USWAP(ustack[n], ustack[u_p - 1 - n]);
123 if (isglobal)
124 clear_active_list();
125 current_addr = u_current_addr, u_current_addr = o_current_addr;
126 addr_last = u_addr_last, u_addr_last = o_addr_last;
127 SPL0();
128 return 0;
129 }
130
131
132 /* clear_undo_stack: clear the undo stack */
133 void
clear_undo_stack(void)134 clear_undo_stack(void)
135 {
136 line_t *lp, *ep, *tl;
137
138 while (u_p--)
139 if (ustack[u_p].type == UDEL) {
140 ep = ustack[u_p].t->q_forw;
141 for (lp = ustack[u_p].h; lp != ep; lp = tl) {
142 unmark_line_node(lp);
143 tl = lp->q_forw;
144 free(lp);
145 }
146 }
147 u_p = 0;
148 u_current_addr = current_addr;
149 u_addr_last = addr_last;
150 }
151