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/*
 * This code contains changes by
 *      Gunnar Ritter, Freiburg i. Br., Germany, 2002. All rights reserved.
 *
 * Conditions 1, 2, and 4 and the no-warranty notice below apply
 * to these changes.
 *
 *
 * Copyright (c) 1980, 1993
 *      The Regents of the University of California.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

#ifndef lint
#ifdef  DOSCCS
static char *sccsid = "@(#)termcap.c    1.7 (gritter) 11/23/04";
#endif
#endif

/* from termcap.c       5.1 (Berkeley) 6/5/85 */

#if 0   /* GR */
#define TCBUFSIZE               1024
#else
#include "libterm.h"
#endif
#define E_TERMCAP       "/etc/termcap"
#define MAXHOP          32      /* max number of tc= indirections */

#include <ctype.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

/*
 * termcap - routines for dealing with the terminal capability data base
 *
 * BUG:         Should use a "last" pointer in tbuf, so that searching
 *              for capabilities alphabetically would not be a n**2/2
 *              process when large numbers of capabilities are given.
 * Note:        If we add a last pointer now we will screw up the
 *              tc capability. We really should compile termcap.
 *
 * Essentially all the work here is scanning and decoding escapes
 * in string capabilities.  We don't use stdio because the editor
 * doesn't, and because living w/o it is not hard.
 */

static  char *tbuf;
static  int hopcount;   /* detect infinite loops in termcap, init 0 */

static int tnamatch(const char *);
static int tnchktc(void);
static char *tskip(register const char *);
static char *tdecode(register char *, char **);

/*
 * Tnamatch deals with name matching.  The first field of the termcap
 * entry is a sequence of names separated by |'s, so we compare
 * against each such name.  The normal : terminator after the last
 * name (before the first field) stops us.
 */
static int
tnamatch(const char *np)
{
        register const char *Np;
        register char *Bp;

        Bp = tbuf;
        if (*Bp == '#')
                return(0);
        for (;;) {
                for (Np = np; *Np && *Bp == *Np; Bp++, Np++)
                        continue;
                if (*Np == 0 && (*Bp == '|' || *Bp == ':' || *Bp == 0))
                        return (1);
                while (*Bp && *Bp != ':' && *Bp != '|')
                        Bp++;
                if (*Bp == 0 || *Bp == ':')
                        return (0);
                Bp++;
        }
}

/*
 * tnchktc: check the last entry, see if it's tc=xxx. If so,
 * recursively find xxx and append that entry (minus the names)
 * to take the place of the tc=xxx entry. This allows termcap
 * entries to say "like an HP2621 but doesn't turn on the labels".
 * Note that this works because of the left to right scan.
 */
static int
tnchktc(void)
{
        register char *p, *q;
        char tcname[16];        /* name of similar terminal */
        char tcbuf[TCBUFSIZE];
        char rmbuf[TCBUFSIZE];
        char *holdtbuf = tbuf, *holdtc;
        int l;

        p = tbuf;
        while (*p) {
                holdtc = p = tskip(p);
                if (!*p)
                        break;
                if (*p++ != 't' || *p == 0 || *p++ != 'c')
                        continue;
                if (*p++ != '=') {
                bad:    write(2, "Bad termcap entry\n", 18);
                        return (0);
                }
                for (q = tcname; *p && *p != ':'; p++) {
                        if (q >= &tcname[sizeof tcname - 1])
                                goto bad;
                        *q++ = *p;
                }
                *q = '\0';
                if (++hopcount > MAXHOP) {
                        write(2, "Infinite tc= loop\n", 18);
                        return (0);
                }
                if (tgetent(tcbuf, tcname) != 1) {
                        hopcount = 0;           /* unwind recursion */
                        return(0);
                }
                hopcount--;
                tbuf = holdtbuf;
                strcpy(rmbuf, &p[1]);
                for (q=tcbuf; *q != ':'; q++)
                        ;
                l = holdtc - holdtbuf + strlen(rmbuf) + strlen(q);
                if (l > TCBUFSIZE) {
                        write(2, "Termcap entry too long\n", 23);
                        break;
                }
                q++;
                for (p = holdtc; *q; q++)
                        *p++ = *q;
                strcpy(p, rmbuf);
                p = holdtc;
        }
        return(1);
}

/*
 * Get an entry for terminal name in buffer bp,
 * from the termcap file.  Parse is very rudimentary;
 * we just notice escaped newlines.
 */
int
tgetent(char *bp, const char *name)
{
        register char *cp;
        register int c;
        register int i = 0, cnt = 0;
        char ibuf[TCBUFSIZE];
        int tf;

        tbuf = bp;
        tf = -1;
#ifndef V6
        cp = getenv("TERMCAP");
        /*
         * TERMCAP can have one of two things in it. It can be the
         * name of a file to use instead of /etc/termcap. In this
         * case it better start with a "/". Or it can be an entry to
         * use so we don't have to read the file. In this case it
         * has to already have the newlines crunched out.
         */
        if (cp && *cp) {
                if (*cp == '/') {
                        tf = open(cp, 0);
                } else {
                        tbuf = cp;
                        c = tnamatch(name);
                        tbuf = bp;
                        if (c) {
                                strcpy(bp,cp);
                                return(tnchktc());
                        }
                }
        }
        if (tf < 0)
                tf = open(E_TERMCAP, 0);
#else
        tf = open(E_TERMCAP, 0);
#endif
        if (tf < 0)
                return (-1);
        for (;;) {
                cp = bp;
                for (;;) {
                        if (i == cnt) {
                                cnt = read(tf, ibuf, TCBUFSIZE);
                                if (cnt <= 0) {
                                        close(tf);
                                        return (0);
                                }
                                i = 0;
                        }
                        c = ibuf[i++];
                        if (c == '\n') {
                                if (cp > bp && cp[-1] == '\\'){
                                        cp--;
                                        continue;
                                }
                                break;
                        }
                        if (cp >= bp+TCBUFSIZE) {
                                write(2,"Termcap entry too long\n", 23);
                                break;
                        } else
                                *cp++ = c;
                }
                *cp = 0;

                /*
                 * The real work for the match.
                 */
                if (tnamatch(name)) {
                        close(tf);
                        return(tnchktc());
                }
        }
}

/*
 * Skip to the next field.  Notice that this is very dumb, not
 * knowing about \: escapes or any such.  If necessary, :'s can be put
 * into the termcap file in octal.
 */
static char *
tskip(register const char *bp)
{

        while (*bp && *bp != ':')
                bp++;
        if (*bp == ':')
                bp++;
        return (char *)bp;
}

/*
 * Return the (numeric) option id.
 * Numeric options look like
 *      li#80
 * i.e. the option string is separated from the numeric value by
 * a # character.  If the option is not found we return -1.
 * Note that we handle octal numbers beginning with 0.
 */
int
tgetnum(char *id)
{
        register int i, base;
        register char *bp = tbuf;

        for (;;) {
                bp = tskip(bp);
                if (*bp == 0)
                        return (-1);
                if (*bp++ != id[0] || *bp == 0 || *bp++ != id[1])
                        continue;
                if (*bp == '@')
                        return(-1);
                if (*bp != '#')
                        continue;
                bp++;
                base = 10;
                if (*bp == '0')
                        base = 8;
                i = 0;
                while (isdigit((*bp & 0377)))
                        i *= base, i += *bp++ - '0';
                return (i);
        }
}

/*
 * Handle a flag option.
 * Flag options are given "naked", i.e. followed by a : or the end
 * of the buffer.  Return 1 if we find the option, or 0 if it is
 * not given.
 */
int
tgetflag(char *id)
{
        register char *bp = tbuf;

        for (;;) {
                bp = tskip(bp);
                if (!*bp)
                        return (0);
                if (*bp++ == id[0] && *bp != 0 && *bp++ == id[1]) {
                        if (!*bp || *bp == ':')
                                return (1);
                        else if (*bp == '@')
                                return(0);
                }
        }
}

/*
 * Get a string valued option.
 * These are given as
 *      cl=^Z
 * Much decoding is done on the strings, and the strings are
 * placed in area, which is a ref parameter which is updated.
 * No checking on area overflow.
 */
char *
tgetstr(char *id, char **area)
{
        register char *bp = tbuf;

        for (;;) {
                bp = tskip(bp);
                if (!*bp)
                        return (0);
                if (*bp++ != id[0] || *bp == 0 || *bp++ != id[1])
                        continue;
                if (*bp == '@')
                        return(0);
                if (*bp != '=')
                        continue;
                bp++;
                return (tdecode(bp, area));
        }
}

/*
 * Tdecode does the grung work to decode the
 * string capability escapes.
 */
static char *
tdecode(register char *str, char **area)
{
        register char *cp;
        register int c;
        register char *dp;
        int i;

        cp = *area;
        while ((c = *str++) && c != ':') {
                switch (c) {

                case '^':
                        c = *str++ & 037;
                        break;

                case '\\':
                        dp = "E\033^^\\\\::n\nr\rt\tb\bf\f";
                        c = *str++;
nextc:
                        if (*dp++ == c) {
                                c = *dp++;
                                break;
                        }
                        dp++;
                        if (*dp)
                                goto nextc;
                        if (isdigit(c)) {
                                c -= '0', i = 2;
                                do
                                        c <<= 3, c |= *str++ - '0';
                                while (--i && isdigit(*str & 0377));
                        }
                        break;
                }
                *cp++ = c;
        }
        *cp++ = 0;
        str = *area;
        *area = cp;
        return (str);
}

/*
*/
static const char sccssl[] = "@(#)libterm.sl    1.7 (gritter) 11/23/04";