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 28 #ifndef lint 29 #if 0 30 static char * const rcsid = "@(#)undo.c,v 1.1 1994/02/01 00:34:44 alm Exp"; 31 #else 32 static char * const rcsid = 33 "$Id: undo.c,v 1.6 1997/02/22 14:03:20 peter Exp $"; 34 #endif 35 #endif /* not lint */ 36 37 #include "ed.h" 38 39 40 #define USIZE 100 /* undo stack size */ 41 undo_t *ustack = NULL; /* undo stack */ 42 long usize = 0; /* stack size variable */ 43 long u_p = 0; /* undo stack pointer */ 44 45 /* push_undo_stack: return pointer to intialized undo node */ 46 undo_t * 47 push_undo_stack(type, from, to) 48 int type; 49 long from; 50 long to; 51 { 52 undo_t *t; 53 54 #if defined(sun) || defined(NO_REALLOC_NULL) 55 if (ustack == NULL && 56 (ustack = (undo_t *) malloc((usize = USIZE) * sizeof(undo_t))) == NULL) { 57 fprintf(stderr, "%s\n", strerror(errno)); 58 sprintf(errmsg, "out of memory"); 59 return NULL; 60 } 61 #endif 62 t = ustack; 63 if (u_p < usize || 64 (t = (undo_t *) realloc(ustack, (usize += USIZE) * sizeof(undo_t))) != NULL) { 65 ustack = t; 66 ustack[u_p].type = type; 67 ustack[u_p].t = get_addressed_line_node(to); 68 ustack[u_p].h = get_addressed_line_node(from); 69 return ustack + u_p++; 70 } 71 /* out of memory - release undo stack */ 72 fprintf(stderr, "%s\n", strerror(errno)); 73 sprintf(errmsg, "out of memory"); 74 clear_undo_stack(); 75 free(ustack); 76 ustack = NULL; 77 usize = 0; 78 return NULL; 79 } 80 81 82 /* USWAP: swap undo nodes */ 83 #define USWAP(x,y) { \ 84 undo_t utmp; \ 85 utmp = x, x = y, y = utmp; \ 86 } 87 88 89 long u_current_addr = -1; /* if >= 0, undo enabled */ 90 long u_addr_last = -1; /* if >= 0, undo enabled */ 91 92 /* pop_undo_stack: undo last change to the editor buffer */ 93 int 94 pop_undo_stack() 95 { 96 long n; 97 long o_current_addr = current_addr; 98 long o_addr_last = addr_last; 99 100 if (u_current_addr == -1 || u_addr_last == -1) { 101 sprintf(errmsg, "nothing to undo"); 102 return ERR; 103 } else if (u_p) 104 modified = 1; 105 get_addressed_line_node(0); /* this get_addressed_line_node last! */ 106 SPL1(); 107 for (n = u_p; n-- > 0;) { 108 switch(ustack[n].type) { 109 case UADD: 110 REQUE(ustack[n].h->q_back, ustack[n].t->q_forw); 111 break; 112 case UDEL: 113 REQUE(ustack[n].h->q_back, ustack[n].h); 114 REQUE(ustack[n].t, ustack[n].t->q_forw); 115 break; 116 case UMOV: 117 case VMOV: 118 REQUE(ustack[n - 1].h, ustack[n].h->q_forw); 119 REQUE(ustack[n].t->q_back, ustack[n - 1].t); 120 REQUE(ustack[n].h, ustack[n].t); 121 n--; 122 break; 123 default: 124 /*NOTREACHED*/ 125 ; 126 } 127 ustack[n].type ^= 1; 128 } 129 /* reverse undo stack order */ 130 for (n = u_p; n-- > (u_p + 1)/ 2;) 131 USWAP(ustack[n], ustack[u_p - 1 - n]); 132 if (isglobal) 133 clear_active_list(); 134 current_addr = u_current_addr, u_current_addr = o_current_addr; 135 addr_last = u_addr_last, u_addr_last = o_addr_last; 136 SPL0(); 137 return 0; 138 } 139 140 141 /* clear_undo_stack: clear the undo stack */ 142 void 143 clear_undo_stack() 144 { 145 line_t *lp, *ep, *tl; 146 147 while (u_p--) 148 if (ustack[u_p].type == UDEL) { 149 ep = ustack[u_p].t->q_forw; 150 for (lp = ustack[u_p].h; lp != ep; lp = tl) { 151 unmark_line_node(lp); 152 tl = lp->q_forw; 153 free(lp); 154 } 155 } 156 u_p = 0; 157 u_current_addr = current_addr; 158 u_addr_last = addr_last; 159 } 160