Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

152 lines (137 sloc) 4.403 kb
/* 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.
*
* @(#)undo.c,v 1.1 1994/02/01 00:34:44 alm Exp
* $FreeBSD: src/bin/ed/undo.c,v 1.12 2002/06/30 05:13:53 obrien Exp $
* $DragonFly: src/bin/ed/undo.c,v 1.4 2007/04/06 23:36:54 pavalos Exp $
*/
#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 initialized undo node */
undo_t *
push_undo_stack(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));
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));
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(void)
{
long n;
long o_current_addr = current_addr;
long o_addr_last = addr_last;
if (u_current_addr == -1 || u_addr_last == -1) {
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(void)
{
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;
}
Jump to Line
Something went wrong with that request. Please try again.