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