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    /*	$OpenBSD: undo.c,v 1.14 2016/03/22 17:58:28 mmcc Exp $	*/  | 
    
    
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    /*	$NetBSD: undo.c,v 1.2 1995/03/21 09:04:52 cgd Exp $	*/  | 
    
    
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    /* 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 <regex.h>  | 
    
    
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    #include <signal.h>  | 
    
    
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    #include <stdio.h>  | 
    
    
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    #include <stdlib.h>  | 
    
    
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    #include "ed.h"  | 
    
    
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    #define USIZE 100				/* undo stack size */  | 
    
    
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    static undo_t *ustack = NULL;			/* undo stack */  | 
    
    
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    static int usize = 0;				/* stack size variable */  | 
    
    
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    static int 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, int from, int to)  | 
    
    
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    { | 
    
    
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    	undo_t *t;  | 
    
    
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    	t = ustack;  | 
    
    
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    	if (u_p < usize ||  | 
    
    
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    	    (t = reallocarray(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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    	perror(NULL);  | 
    
    
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    	seterrmsg("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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    int u_current_addr = -1;	/* if >= 0, undo enabled */  | 
    
    
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    int 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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    	int n;  | 
    
    
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    	int o_current_addr = current_addr;  | 
    
    
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    	int o_addr_last = addr_last;  | 
    
    
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    	if (u_current_addr == -1 || u_addr_last == -1) { | 
    
    
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    		seterrmsg("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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    }  |