usr/src/usr.sbin/lpr/common_source/printcap.c

/*      printcap.c      1.1     81/05/09        */
/* Copyright (c) 1979 Regents of the University of California */
#define BUFSIZ  512

#include <ctype.h>
/*
 * printcap - routines for dealing with the line printer 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.
 *
 * 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 *pbuf;
char    *pskip();
char    *pgetstr();
char    *pdecode();

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

        pbuf = bp;
        tf = open("/etc/printcap", 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;
                        }
                        *cp++ = c;
                }
                *cp = 0;

                /*
                 * The real work for the match.
                 */
                if (pnamatch(name)) {
                        close(tf);
                        return (1);
                }
        }
}

/*
 * Tnamatch deals with name matching.  The first field of the printcap
 * 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.
 */
pnamatch(np)
        char *np;
{
        register char *Np, *Bp;

        Bp = pbuf;
        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 printcap file in octal.
 */
static char *
pskip(bp)
        register 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.
 */
pgetnum(id)
        char *id;
{
        register int i, base;
        register char *bp = pbuf;

        for (;;) {
                bp = pskip(bp);
                if (*bp == 0)
                        return (-1);
                if (*bp++ != id[0] || *bp == 0 || *bp++ != id[1])
                        continue;
                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.
 */
pgetflag(id)
        char *id;
{
        register char *bp = pbuf;

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

/*
 * 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 *
pgetstr(id, area)
        char *id, **area;
{
        register char *bp = pbuf;

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

/*
 * Tdecode does the grung work to decode the
 * string capability escapes.
 */
static char *
pdecode(str, area)
        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));
                        }
                        break;
                }
                *cp++ = c;
        }
        *cp++ = 0;
        str = *area;
        *area = cp;
        return (str);
}