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