bin/ed/undo.c

   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 *
  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
  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
 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 }