/* undo.c: This file contains the undo routines for the ed line editor */ /*- * Copyright (c) 1993 Andrew Moore, Talke Studio. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint static char *rcsid = "@(#)$Id: undo.c,v 1.2 1993/12/14 16:19:56 alm Exp $"; #endif /* not lint */ #include "ed.h" #define USIZE 100 /* undo stack size */ undo_t *ustack = NULL; /* undo stack */ long usize = 0; /* stack size variable */ long u_p = 0; /* undo stack pointer */ /* push_undo_stack: return pointer to intialized undo node */ undo_t * push_undo_stack(type, from, to) int type; long from; long to; { undo_t *t; #if defined(sun) || defined(NO_REALLOC_NULL) if (ustack == NULL && (ustack = (undo_t *) malloc((usize = USIZE) * sizeof(undo_t))) == NULL) { fprintf(stderr, "%s\n", strerror(errno)); sprintf(errmsg, "out of memory"); return NULL; } #endif t = ustack; if (u_p < usize || (t = (undo_t *) realloc(ustack, (usize += USIZE) * sizeof(undo_t))) != NULL) { ustack = t; ustack[u_p].type = type; ustack[u_p].t = get_addressed_line_node(to); ustack[u_p].h = get_addressed_line_node(from); return ustack + u_p++; } /* out of memory - release undo stack */ fprintf(stderr, "%s\n", strerror(errno)); sprintf(errmsg, "out of memory"); clear_undo_stack(); free(ustack); ustack = NULL; usize = 0; return NULL; } /* USWAP: swap undo nodes */ #define USWAP(x,y) { \ undo_t utmp; \ utmp = x, x = y, y = utmp; \ } long u_current_addr = -1; /* if >= 0, undo enabled */ long u_addr_last = -1; /* if >= 0, undo enabled */ /* pop_undo_stack: undo last change to the editor buffer */ int pop_undo_stack() { long n; long o_current_addr = current_addr; long o_addr_last = addr_last; if (u_current_addr == -1 || u_addr_last == -1) { sprintf(errmsg, "nothing to undo"); return ERR; } else if (u_p) modified = 1; get_addressed_line_node(0); /* this get_addressed_line_node last! */ SPL1(); for (n = u_p; n-- > 0;) { switch(ustack[n].type) { case UADD: REQUE(ustack[n].h->q_back, ustack[n].t->q_forw); break; case UDEL: REQUE(ustack[n].h->q_back, ustack[n].h); REQUE(ustack[n].t, ustack[n].t->q_forw); break; case UMOV: case VMOV: REQUE(ustack[n - 1].h, ustack[n].h->q_forw); REQUE(ustack[n].t->q_back, ustack[n - 1].t); REQUE(ustack[n].h, ustack[n].t); n--; break; default: /*NOTREACHED*/ ; } ustack[n].type ^= 1; } /* reverse undo stack order */ for (n = u_p; n-- > (u_p + 1)/ 2;) USWAP(ustack[n], ustack[u_p - 1 - n]); if (isglobal) clear_active_list(); current_addr = u_current_addr, u_current_addr = o_current_addr; addr_last = u_addr_last, u_addr_last = o_addr_last; SPL0(); return 0; } /* clear_undo_stack: clear the undo stack */ void clear_undo_stack() { line_t *lp, *ep, *tl; while (u_p--) if (ustack[u_p].type == UDEL) { ep = ustack[u_p].t->q_forw; for (lp = ustack[u_p].h; lp != ep; lp = tl) { unmark_line_node(lp); tl = lp->q_forw; free(lp); } } u_p = 0; u_current_addr = current_addr; u_addr_last = addr_last; }