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