usr.bin/rdist/lookup.c

/*
 * Copyright (c) 1983 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
static char sccsid[] = "@(#)lookup.c    5.5 (Berkeley) 6/1/90";
#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.
 */
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);
}