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lookup.c

/*
 * 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
#if 0
static char sccsid[] = "@(#)lookup.c      8.1 (Berkeley) 6/9/93";
#endif
static const char rcsid[] =
  "$FreeBSD$";
#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 = NULL;

      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[BUFSIZ];

      if (debug)
            printf("lookup(%s, %d, %p)\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)snprintf(buf, sizeof(buf),
                            "%s redefined", name);
                        yyerror(buf);
                  }
            }
            return(s->s_value);
      }

      if (action == LOOKUP) {
            (void)snprintf(buf, sizeof(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);
}

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