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/* Part of CPP library. (Macro hash table support.)
* Copyright (C) 1986, 87, 89, 92, 93, 94, 1995 Free Software Foundation, Inc.
* Written by Per Bothner, 1994.
* Based on CCCP program by by Paul Rubin, June 1986
* Adapted to ANSI C, Richard Stallman, Jan 1987
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
* In other words, you are welcome to use, share and improve this program.
* You are forbidden to forbid anyone else to use, share and improve
* what you give them. Help stamp out software-hoarding! */
#include "cpplib.h"
#include "cpphash.h"
static HASHNODE *hashtab[HASHSIZE];
#include <string.h>
#include <stdlib.h>
#define IS_IDCHAR(ch) is_idchar[(unsigned char)(ch)]
/*
* return hash function on name. must be compatible with the one
* computed a step at a time, elsewhere
*/
int
hashf(const char *name, int len, int hashsize)
{
int r = 0;
while (len--)
r = HASHSTEP(r, *name++);
return MAKE_POS(r) % hashsize;
}
/*
* find the most recent hash node for name name (ending with first
* non-identifier char) installed by install
*
* If LEN is >= 0, it is the length of the name.
* Otherwise, compute the length by scanning the entire name.
*
* If HASH is >= 0, it is the precomputed hash code.
* Otherwise, compute the hash code.
*/
HASHNODE *
cpp_lookup(const char *name, int len, int hash)
{
const char *bp;
HASHNODE *bucket;
if (len < 0)
{
for (bp = name; IS_IDCHAR(*bp); bp++)
;
len = bp - name;
}
if (hash < 0)
hash = hashf(name, len, HASHSIZE);
bucket = hashtab[hash];
while (bucket)
{
if (bucket->length == len
&& strncmp((const char *)bucket->name, name, len) == 0)
return bucket;
bucket = bucket->next;
}
return (HASHNODE *) 0;
}
/*
* Delete a hash node. Some weirdness to free junk from macros.
* More such weirdness will have to be added if you define more hash
* types that need it.
*/
/* Note that the DEFINITION of a macro is removed from the hash table
* but its storage is not freed. This would be a storage leak
* except that it is not reasonable to keep undefining and redefining
* large numbers of macros many times.
* In any case, this is necessary, because a macro can be #undef'd
* in the middle of reading the arguments to a call to it.
* If #undef freed the DEFINITION, that would crash. */
void
delete_macro(HASHNODE * hp)
{
if (hp->prev != NULL)
hp->prev->next = hp->next;
if (hp->next != NULL)
hp->next->prev = hp->prev;
/* make sure that the bucket chain header that
* the deleted guy was on points to the right thing afterwards. */
if (hp == *hp->bucket_hdr)
*hp->bucket_hdr = hp->next;
if (hp->type == T_MACRO)
{
DEFINITION *d = hp->value.defn;
struct reflist *ap, *nextap;
for (ap = d->pattern; ap != NULL; ap = nextap)
{
nextap = ap->next;
free(ap);
}
if (d->nargs >= 0)
free(d->args.argnames);
free(d);
}
free(hp);
}
/*
* install a name in the main hash table, even if it is already there.
* name stops with first non alphanumeric, except leading '#'.
* caller must check against redefinition if that is desired.
* delete_macro () removes things installed by install () in fifo order.
* this is important because of the `defined' special symbol used
* in #if, and also if pushdef/popdef directives are ever implemented.
*
* If LEN is >= 0, it is the length of the name.
* Otherwise, compute the length by scanning the entire name.
*
* If HASH is >= 0, it is the precomputed hash code.
* Otherwise, compute the hash code.
*/
HASHNODE *
install(const char *name, int len, enum node_type type, int ivalue, char *value,
int hash)
{
HASHNODE *hp;
int i, bucket;
const char *p;
if (len < 0)
{
p = name;
while (IS_IDCHAR(*p))
p++;
len = p - name;
}
if (hash < 0)
hash = hashf(name, len, HASHSIZE);
i = sizeof(HASHNODE) + len + 1;
hp = (HASHNODE *) xmalloc(i);
bucket = hash;
hp->bucket_hdr = &hashtab[bucket];
hp->next = hashtab[bucket];
hashtab[bucket] = hp;
hp->prev = NULL;
if (hp->next != NULL)
hp->next->prev = hp;
hp->type = type;
hp->length = len;
if (hp->type == T_CONST)
hp->value.ival = ivalue;
else
hp->value.cpval = value;
hp->name = ((char *)hp) + sizeof(HASHNODE);
memcpy(hp->name, name, len);
hp->name[len] = 0;
return hp;
}
void
cpp_hash_cleanup(cpp_reader * pfile)
{
int i;
pfile = NULL;
for (i = HASHSIZE; --i >= 0;)
{
while (hashtab[i])
delete_macro(hashtab[i]);
}
}
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