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: src/bin/ed/undo.c,v 1.9 1999/08/27 23:14:15 peter Exp $ 29 * $DragonFly: src/bin/ed/undo.c,v 1.3 2003/09/28 14:39:14 hmp Exp $ 30 */ 31 32 #include "ed.h" 33 34 35 #define USIZE 100 /* undo stack size */ 36 undo_t *ustack = NULL; /* undo stack */ 37 long usize = 0; /* stack size variable */ 38 long u_p = 0; /* undo stack pointer */ 39 40 /* push_undo_stack: return pointer to initialized undo node */ 41 undo_t * 42 push_undo_stack(int type, long from, long to) 43 { 44 undo_t *t; 45 46 #if defined(sun) || defined(NO_REALLOC_NULL) 47 if (ustack == NULL && 48 (ustack = (undo_t *) malloc((usize = USIZE) * sizeof(undo_t))) == NULL) { 49 fprintf(stderr, "%s\n", strerror(errno)); 50 sprintf(errmsg, "out of memory"); 51 return NULL; 52 } 53 #endif 54 t = ustack; 55 if (u_p < usize || 56 (t = (undo_t *) realloc(ustack, (usize += USIZE) * sizeof(undo_t))) != NULL) { 57 ustack = t; 58 ustack[u_p].type = type; 59 ustack[u_p].t = get_addressed_line_node(to); 60 ustack[u_p].h = get_addressed_line_node(from); 61 return ustack + u_p++; 62 } 63 /* out of memory - release undo stack */ 64 fprintf(stderr, "%s\n", strerror(errno)); 65 sprintf(errmsg, "out of memory"); 66 clear_undo_stack(); 67 free(ustack); 68 ustack = NULL; 69 usize = 0; 70 return NULL; 71 } 72 73 74 /* USWAP: swap undo nodes */ 75 #define USWAP(x,y) { \ 76 undo_t utmp; \ 77 utmp = x, x = y, y = utmp; \ 78 } 79 80 81 long u_current_addr = -1; /* if >= 0, undo enabled */ 82 long u_addr_last = -1; /* if >= 0, undo enabled */ 83 84 /* pop_undo_stack: undo last change to the editor buffer */ 85 int 86 pop_undo_stack(void) 87 { 88 long n; 89 long o_current_addr = current_addr; 90 long o_addr_last = addr_last; 91 92 if (u_current_addr == -1 || u_addr_last == -1) { 93 sprintf(errmsg, "nothing to undo"); 94 return ERR; 95 } else if (u_p) 96 modified = 1; 97 get_addressed_line_node(0); /* this get_addressed_line_node last! */ 98 SPL1(); 99 for (n = u_p; n-- > 0;) { 100 switch(ustack[n].type) { 101 case UADD: 102 REQUE(ustack[n].h->q_back, ustack[n].t->q_forw); 103 break; 104 case UDEL: 105 REQUE(ustack[n].h->q_back, ustack[n].h); 106 REQUE(ustack[n].t, ustack[n].t->q_forw); 107 break; 108 case UMOV: 109 case VMOV: 110 REQUE(ustack[n - 1].h, ustack[n].h->q_forw); 111 REQUE(ustack[n].t->q_back, ustack[n - 1].t); 112 REQUE(ustack[n].h, ustack[n].t); 113 n--; 114 break; 115 default: 116 /*NOTREACHED*/ 117 ; 118 } 119 ustack[n].type ^= 1; 120 } 121 /* reverse undo stack order */ 122 for (n = u_p; n-- > (u_p + 1)/ 2;) 123 USWAP(ustack[n], ustack[u_p - 1 - n]); 124 if (isglobal) 125 clear_active_list(); 126 current_addr = u_current_addr, u_current_addr = o_current_addr; 127 addr_last = u_addr_last, u_addr_last = o_addr_last; 128 SPL0(); 129 return 0; 130 } 131 132 133 /* clear_undo_stack: clear the undo stack */ 134 void 135 clear_undo_stack(void) 136 { 137 line_t *lp, *ep, *tl; 138 139 while (u_p--) 140 if (ustack[u_p].type == UDEL) { 141 ep = ustack[u_p].t->q_forw; 142 for (lp = ustack[u_p].h; lp != ep; lp = tl) { 143 unmark_line_node(lp); 144 tl = lp->q_forw; 145 free(lp); 146 } 147 } 148 u_p = 0; 149 u_current_addr = current_addr; 150 u_addr_last = addr_last; 151 } 152