diff options
Diffstat (limited to 'bin/ed/undo.c')
| -rw-r--r-- | bin/ed/undo.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/bin/ed/undo.c b/bin/ed/undo.c new file mode 100644 index 0000000..4291be0 --- /dev/null +++ b/bin/ed/undo.c @@ -0,0 +1,146 @@ +/* $OpenBSD: undo.c,v 1.14 2016/03/22 17:58:28 mmcc Exp $ */ +/* $NetBSD: undo.c,v 1.2 1995/03/21 09:04:52 cgd Exp $ */ + +/* 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. + */ + +#include <regex.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> + +#include "ed.h" + +#define USIZE 100 /* undo stack size */ +static undo_t *ustack = NULL; /* undo stack */ +static int usize = 0; /* stack size variable */ +static int u_p = 0; /* undo stack pointer */ + +/* push_undo_stack: return pointer to initialized undo node */ +undo_t * +push_undo_stack(int type, int from, int to) +{ + undo_t *t; + + t = ustack; + if (u_p < usize || + (t = reallocarray(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 */ + perror(NULL); + seterrmsg("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; \ +} + + +int u_current_addr = -1; /* if >= 0, undo enabled */ +int u_addr_last = -1; /* if >= 0, undo enabled */ + +/* pop_undo_stack: undo last change to the editor buffer */ +int +pop_undo_stack(void) +{ + int n; + int o_current_addr = current_addr; + int o_addr_last = addr_last; + + if (u_current_addr == -1 || u_addr_last == -1) { + seterrmsg("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; +} |