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