Il CD di internet/CD.iso/SOURCE/N/TCPIP/NETKIT-B.05/NETKIT-B/NetKit-B-0.05/rdist/lookup.c

C/C++ Source or Header | 1994-03-07 | 4.2 KB | 168 lines

/*
 * Copyright (c) 1983, 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
/* from: static char sccsid[] = "@(#)lookup.c    8.1 (Berkeley) 6/9/93"; */
static char *rcsid = "$Id: lookup.c,v 1.3 1994/03/07 05:05:33 cgd Exp $";
#endif /* not lint */

#include "defs.h"

    /* symbol types */
#define VAR    1
#define CONST    2

struct syment {
    int    s_type;
    char    *s_name;
    struct    namelist *s_value;
    struct    syment *s_next;
};

static struct syment *hashtab[HASHSIZE];

/*
 * Define a variable from a command line argument.
 */
void
define(name)
    char *name;
{
    register char *cp, *s;
    register struct namelist *nl;
    struct namelist *value;

    if (debug)
        printf("define(%s)\n", name);

    cp = index(name, '=');
    if (cp == NULL)
        value = NULL;
    else if (cp[1] == '\0') {
        *cp = '\0';
        value = NULL;
    } else if (cp[1] != '(') {
        *cp++ = '\0';
        value = makenl(cp);
    } else {
        nl = NULL;
        *cp++ = '\0';
        do
            cp++;
        while (*cp == ' ' || *cp == '\t');
        for (s = cp; ; s++) {
            switch (*s) {
            case ')':
                *s = '\0';
            case '\0':
                break;
            case ' ':
            case '\t':
                *s++ = '\0';
                while (*s == ' ' || *s == '\t')
                    s++;
                if (*s == ')')
                    *s = '\0';
                break;
            default:
                continue;
            }
            if (nl == NULL)
                value = nl = makenl(cp);
            else {
                nl->n_next = makenl(cp);
                nl = nl->n_next;
            }
            if (*s == '\0')
                break;
            cp = s;
        }
    }
    (void) lookup(name, REPLACE, value);
}

/*
 * Lookup name in the table and return a pointer to it.
 * LOOKUP - just do lookup, return NULL if not found.
 * INSERT - insert name with value, error if already defined.
 * REPLACE - insert or replace name with value.
 */

struct namelist *
lookup(name, action, value)
    char *name;
    int action;
    struct namelist *value;
{
    register unsigned n;
    register char *cp;
    register struct syment *s;
    char buf[256];

    if (debug)
        printf("lookup(%s, %d, %x)\n", name, action, value);

    n = 0;
    for (cp = name; *cp; )
        n += *cp++;
    n %= HASHSIZE;

    for (s = hashtab[n]; s != NULL; s = s->s_next) {
        if (strcmp(name, s->s_name))
            continue;
        if (action != LOOKUP) {
            if (action != INSERT || s->s_type != CONST) {
                (void)sprintf(buf, "%s redefined", name);
                yyerror(buf);
            }
        }
        return(s->s_value);
    }

    if (action == LOOKUP) {
        (void)sprintf(buf, "%s undefined", name);
        yyerror(buf);
        return(NULL);
    }

    s = ALLOC(syment);
    if (s == NULL)
        fatal("ran out of memory\n");
    s->s_next = hashtab[n];
    hashtab[n] = s;
    s->s_type = action == INSERT ? VAR : CONST;
    s->s_name = name;
    s->s_value = value;
    return(value);
}