1 /* $NetBSD: undo.c,v 1.3 1997/07/20 06:35:42 thorpej 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 1.3 1997/07/20 06:35:42 thorpej 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 intialized undo node */ 48 undo_t * 49 push_undo_stack(type, from, to) 50 int type; 51 long from; 52 long to; 53 { 54 undo_t *t; 55 56 #if defined(sun) || defined(NO_REALLOC_NULL) 57 if (ustack == NULL && 58 (ustack = (undo_t *) malloc((usize = USIZE) * sizeof(undo_t))) == NULL) { 59 fprintf(stderr, "%s\n", strerror(errno)); 60 sprintf(errmsg, "out of memory"); 61 return NULL; 62 } 63 #endif 64 t = ustack; 65 if (u_p < usize || 66 (t = (undo_t *) realloc(ustack, (usize += USIZE) * sizeof(undo_t))) != NULL) { 67 ustack = t; 68 ustack[u_p].type = type; 69 ustack[u_p].t = get_addressed_line_node(to); 70 ustack[u_p].h = get_addressed_line_node(from); 71 return ustack + u_p++; 72 } 73 /* out of memory - release undo stack */ 74 fprintf(stderr, "%s\n", strerror(errno)); 75 sprintf(errmsg, "out of memory"); 76 clear_undo_stack(); 77 free(ustack); 78 ustack = NULL; 79 usize = 0; 80 return NULL; 81 } 82 83 84 /* USWAP: swap undo nodes */ 85 #define USWAP(x,y) { \ 86 undo_t utmp; \ 87 utmp = x, x = y, y = utmp; \ 88 } 89 90 91 long u_current_addr = -1; /* if >= 0, undo enabled */ 92 long u_addr_last = -1; /* if >= 0, undo enabled */ 93 94 /* pop_undo_stack: undo last change to the editor buffer */ 95 int 96 pop_undo_stack() 97 { 98 long n; 99 long o_current_addr = current_addr; 100 long o_addr_last = addr_last; 101 102 if (u_current_addr == -1 || u_addr_last == -1) { 103 sprintf(errmsg, "nothing to undo"); 104 return ERR; 105 } else if (u_p) 106 modified = 1; 107 get_addressed_line_node(0); /* this get_addressed_line_node last! */ 108 SPL1(); 109 for (n = u_p; n-- > 0;) { 110 switch(ustack[n].type) { 111 case UADD: 112 REQUE(ustack[n].h->q_back, ustack[n].t->q_forw); 113 break; 114 case UDEL: 115 REQUE(ustack[n].h->q_back, ustack[n].h); 116 REQUE(ustack[n].t, ustack[n].t->q_forw); 117 break; 118 case UMOV: 119 case VMOV: 120 REQUE(ustack[n - 1].h, ustack[n].h->q_forw); 121 REQUE(ustack[n].t->q_back, ustack[n - 1].t); 122 REQUE(ustack[n].h, ustack[n].t); 123 n--; 124 break; 125 default: 126 /*NOTREACHED*/ 127 ; 128 } 129 ustack[n].type ^= 1; 130 } 131 /* reverse undo stack order */ 132 for (n = u_p; n-- > (u_p + 1)/ 2;) 133 USWAP(ustack[n], ustack[u_p - 1 - n]); 134 if (isglobal) 135 clear_active_list(); 136 current_addr = u_current_addr, u_current_addr = o_current_addr; 137 addr_last = u_addr_last, u_addr_last = o_addr_last; 138 SPL0(); 139 return 0; 140 } 141 142 143 /* clear_undo_stack: clear the undo stack */ 144 void 145 clear_undo_stack() 146 { 147 line_t *lp, *ep, *tl; 148 149 while (u_p--) 150 if (ustack[u_p].type == UDEL) { 151 ep = ustack[u_p].t->q_forw; 152 for (lp = ustack[u_p].h; lp != ep; lp = tl) { 153 unmark_line_node(lp); 154 tl = lp->q_forw; 155 free(lp); 156 } 157 } 158 u_p = 0; 159 u_current_addr = current_addr; 160 u_addr_last = addr_last; 161 } 162