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

#define BUFSIZ  1024
#define MAXHOP  32      /* max number of tc= indirections */

#include <ctype.h>
#include <locale.h>
#include <string.h>
/*
 * grindcap - routines for dealing with the language definitions data base
 *      (code stolen almost totally from termcap)
 *
 * 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  char *filename;
static  int hopcount;   /* detect infinite loops in termcap, init 0 */
char    *tgetstr();
char    *getenv();

static char *tdecode(char *str, char **area);
static char *tskip(char *bp);
static int tnchktc(void);
static int tnamatch(char *np);

static char     *vgrind_msg;

/*
 * 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, char *name, char *file)
{
        char *cp;
        int c;
        int i = 0, cnt = 0;
        char ibuf[BUFSIZ];
        char *cp2;
        int tf;

        tbuf = bp;
        tf = 0;
        filename = file;
        tf = open(filename, 0);
        if (tf < 0)
                return (-1);
        for (;;) {
                cp = bp;
                for (;;) {
                        if (i == cnt) {
                                cnt = read(tf, ibuf, BUFSIZ);
                                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+BUFSIZ) {
                                vgrind_msg = gettext("Vgrind entry too long\n");
                                write(2, vgrind_msg, strlen(vgrind_msg));
                                break;
                        } else
                                *cp++ = c;
                }
                *cp = 0;

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

/*
 * 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)
{
        char *p, *q;
        char tcname[16];        /* name of similar terminal */
        char tcbuf[BUFSIZ];
        char *holdtbuf = tbuf;
        int l;

        p = tbuf + strlen(tbuf) - 2;    /* before the last colon */
        while (*--p != ':')
                if (p<tbuf) {
                        vgrind_msg = gettext("Bad vgrind entry\n");
                        write(2, vgrind_msg, strlen(vgrind_msg));
                        return (0);
                }
        p++;
        /* p now points to beginning of last field */
        if (p[0] != 't' || p[1] != 'c')
                return(1);
        strcpy(tcname,p+3);
        q = tcname;
        while (q && *q != ':')
                q++;
        *q = 0;
        if (++hopcount > MAXHOP) {
                vgrind_msg = gettext("Infinite tc= loop\n");
                write(2, vgrind_msg, strlen(vgrind_msg));
                return (0);
        }
        if (tgetent(tcbuf, tcname, filename) != 1)
                return(0);
        for (q=tcbuf; *q != ':'; q++)
                ;
        l = p - holdtbuf + strlen(q);
        if (l > BUFSIZ) {
                vgrind_msg = gettext("Vgrind entry too long\n");
                write(2, vgrind_msg, strlen(vgrind_msg));
                q[BUFSIZ - (p-tbuf)] = 0;
        }
        strcpy(p, q+1);
        tbuf = holdtbuf;
        return(1);
}

/*
 * 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(char *np)
{
        char *Np, *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++;
        }
}

/*
 * 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(char *bp)
{

        while (*bp && *bp != ':')
                bp++;
        if (*bp == ':')
                bp++;
        return (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.
 */
static int
tgetnum(char *id)
{
        int i, base;
        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))
                        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)
{
        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)
{
        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(char *str, char **area)
{
        char *cp;
        int c;
        int i;

        cp = *area;
        while (c = *str++) {
            if (c == ':' && *(cp-1) != '\\')
                break;
            *cp++ = c;
        }
        *cp++ = 0;
        str = *area;
        *area = cp;
        return (str);
}