/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
/*        All Rights Reserved   */

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

#include "sh.h"
#include "sh.tconst.h"

struct Hist Histlist;
int     eventno;

struct Hist *enthist(int, struct wordent *, bool);
void    hfree(struct Hist *);
void    dohist1(struct Hist *, int *, int, int);
void    phist(struct Hist *, int);

/*
 * C shell
 */

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

#ifdef TRACE
        tprintf("TRACE- savehist()\n");
#endif
        /* throw away null lines */
        if (sp->next->word[0] == '\n')
                return;
        cp = value(S_history /*"history"*/);
        if (*cp) {
                tchar *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(int event, struct wordent *lp, bool docopy)
{
        struct Hist *np;

#ifdef TRACE
        tprintf("TRACE- enthist()\n");
#endif
        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);
}

void
hfree(struct Hist *hp)
{
#ifdef TRACE
        tprintf("TRACE- hfree()\n");
#endif

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

void
dohist(tchar **vp)
{
        int n, rflg = 0, hflg = 0;
#ifdef TRACE
        tprintf("TRACE- dohist()\n");
#endif
        if (getn(value(S_history /*"history"*/)) == 0)
                return;
        if (setintr)
                (void) sigsetmask(sigblock(0) & ~sigmask(SIGINT));
        while (*++vp && **vp == '-') {
                tchar *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(S_history /*"history"*/));
        }
        dohist1(Histlist.Hnext, &n, rflg, hflg);
}

void
dohist1(struct Hist *hp, int *np, int rflg, int hflg)
{
        bool print = (*np) > 0;
#ifdef TRACE
        tprintf("TRACE- dohist1()\n");
#endif
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;
}

void
phist(struct Hist *hp, int hflg)
{
#ifdef TRACE
        tprintf("TRACE- phist()\n");
#endif

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