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