/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley Software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#if	!defined(lint) && defined(DOSCCS)
static char *sccsid = "@(#)sh.hist.c	5.2 (Berkeley) 6/6/85";
#endif

#include "sh.h"

/*
 * C shell
 */

savehist(sp)
	struct wordent *sp;
{
	register struct Hist *hp, *np;
	register int histlen = 0;
	char *cp;

	/* throw away null lines */
	if (sp->next->word[0] == '\n')
		return;
	cp = value("history");
	if (*cp) {
		register char *p = cp;

		while (*p) {
			if (!digit(*p)) {
				histlen = 0;
				break;
			}
			histlen = histlen * 10 + *p++ - '0';
		}
	}
	for (hp = &Histlist; np = hp->Hnext;)
		if (eventno - np->Href >= histlen || histlen == 0)
			hp->Hnext = np->Hnext, hfree(np);
		else
			hp = np;
	(void) enthist(++eventno, sp, 1);
}

struct Hist *
enthist(event, lp, docopy)
	int event;
	register struct wordent *lp;
	bool docopy;
{
	register struct Hist *np;

	np = (struct Hist *) xalloc(sizeof *np);
	np->Hnum = np->Href = event;
	if (docopy)
		copylex(&np->Hlex, lp);
	else {
		np->Hlex.next = lp->next;
		lp->next->prev = &np->Hlex;
		np->Hlex.prev = lp->prev;
		lp->prev->next = &np->Hlex;
	}
	np->Hnext = Histlist.Hnext;
	Histlist.Hnext = np;
	return (np);
}

hfree(hp)
	register struct Hist *hp;
{

	freelex(&hp->Hlex);
	xfree((char *)hp);
}

dohist(vp)
	char **vp;
{
	int n, rflg = 0, hflg = 0;
	if (getn(value("history")) == 0)
		return;
	if (setintr)
		(void) sigsetmask(sigblock(0L) & ~sigmask(SIGINT));
 	while (*++vp && **vp == '-') {
 		char *vp2 = *vp;
 
 		while (*++vp2)
 			switch (*vp2) {
 			case 'h':
 				hflg++;
 				break;
 			case 'r':
 				rflg++;
 				break;
 			case '-':	/* ignore multiple '-'s */
 				break;
 			default:
 				printf("Unknown flag: -%c\n", *vp2);
 				error("Usage: history [-rh] [# number of events]");
			}
	}
	if (*vp)
		n = getn(*vp);
	else {
		n = getn(value("history"));
	}
	dohist1(Histlist.Hnext, &n, rflg, hflg);
}

dohist1(hp, np, rflg, hflg)
	struct Hist *hp;
	int *np, rflg, hflg;
{
	bool print = (*np) > 0;
top:
	if (hp == 0)
		return;
	(*np)--;
	hp->Href++;
	if (rflg == 0) {
		dohist1(hp->Hnext, np, rflg, hflg);
		if (print)
			phist(hp, hflg);
		return;
	}
	if (*np >= 0)
		phist(hp, hflg);
	hp = hp->Hnext;
	goto top;
}

phist(hp, hflg)
	register struct Hist *hp;
	int hflg;
{

	if (hflg == 0)
		printf("%6d\t", hp->Hnum);
	prlex(&hp->Hlex);
}
