mirror of
https://github.com/FirebirdSQL/firebird.git
synced 2025-01-24 23:23:03 +01:00
166 lines
3.5 KiB
C++
166 lines
3.5 KiB
C++
/*
|
|
* PROGRAM: JRD access method
|
|
* MODULE: hsh.c
|
|
* DESCRIPTION: Hash table and symbol manager
|
|
*
|
|
* The contents of this file are subject to the Interbase Public
|
|
* License Version 1.0 (the "License"); you may not use this file
|
|
* except in compliance with the License. You may obtain a copy
|
|
* of the License at http://www.Inprise.com/IPL.html
|
|
*
|
|
* Software distributed under the License is distributed on an
|
|
* "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
|
|
* or implied. See the License for the specific language governing
|
|
* rights and limitations under the License.
|
|
*
|
|
* The Original Code was created by Inprise Corporation
|
|
* and its predecessors. Portions created by Inprise Corporation are
|
|
* Copyright (C) Inprise Corporation.
|
|
*
|
|
* All Rights Reserved.
|
|
* Contributor(s): ______________________________________.
|
|
*/
|
|
|
|
#include "firebird.h"
|
|
#include <string.h>
|
|
#include "../jrd/jrd.h"
|
|
#include "../jrd/val.h"
|
|
#include "../jrd/err_proto.h"
|
|
#include "../jrd/sym_proto.h"
|
|
#include "../jrd/thd_proto.h"
|
|
|
|
|
|
extern "C" {
|
|
|
|
|
|
static SSHORT hash_func(SCHAR *);
|
|
|
|
|
|
void SYM_insert(SYM symbol)
|
|
{
|
|
/**************************************
|
|
*
|
|
* S Y M _ i n s e r t
|
|
*
|
|
**************************************
|
|
*
|
|
* Functional description
|
|
* Insert a symbol into the hash table.
|
|
*
|
|
**************************************/
|
|
DBB dbb;
|
|
int h;
|
|
SYM old;
|
|
|
|
dbb = GET_DBB;
|
|
|
|
h = hash_func(symbol->sym_string);
|
|
|
|
for (old = dbb->dbb_hash_table[h]; old; old = old->sym_collision)
|
|
if (!strcmp(symbol->sym_string, old->sym_string)) {
|
|
symbol->sym_homonym = old->sym_homonym;
|
|
old->sym_homonym = symbol;
|
|
return;
|
|
}
|
|
|
|
symbol->sym_collision = dbb->dbb_hash_table[h];
|
|
dbb->dbb_hash_table[h] = symbol;
|
|
}
|
|
|
|
|
|
SYM SYM_lookup(TEXT * string)
|
|
{
|
|
/**************************************
|
|
*
|
|
* S Y M _ l o o k u p
|
|
*
|
|
**************************************
|
|
*
|
|
* Functional description
|
|
* Perform a string lookup against hash table.
|
|
*
|
|
**************************************/
|
|
DBB dbb;
|
|
SYM symbol;
|
|
|
|
dbb = GET_DBB;
|
|
|
|
for (symbol = dbb->dbb_hash_table[hash_func(string)]; symbol;
|
|
symbol = symbol->sym_collision)
|
|
if (!strcmp(string, symbol->sym_string)) return symbol;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
|
|
void SYM_remove(SYM symbol)
|
|
{
|
|
/**************************************
|
|
*
|
|
* S Y M _ r e m o v e
|
|
*
|
|
**************************************
|
|
*
|
|
* Functional description
|
|
* Remove a symbol from the hash table.
|
|
*
|
|
**************************************/
|
|
DBB dbb;
|
|
int h;
|
|
SYM *next, *ptr, homonym;
|
|
|
|
dbb = GET_DBB;
|
|
|
|
h = hash_func(symbol->sym_string);
|
|
|
|
for (next = &dbb->dbb_hash_table[h]; *next;
|
|
next = &(*next)->sym_collision) if (symbol == *next)
|
|
if ( (homonym = symbol->sym_homonym) ) {
|
|
homonym->sym_collision = symbol->sym_collision;
|
|
*next = homonym;
|
|
return;
|
|
}
|
|
else {
|
|
*next = symbol->sym_collision;
|
|
return;
|
|
}
|
|
else
|
|
for (ptr = &(*next)->sym_homonym; *ptr;
|
|
ptr = &(*ptr)->sym_homonym) if (symbol == *ptr) {
|
|
*ptr = symbol->sym_homonym;
|
|
return;
|
|
}
|
|
|
|
BUGCHECK(164); /* msg 164 failed to remove symbol from hash table */
|
|
}
|
|
|
|
|
|
static SSHORT hash_func(SCHAR * string)
|
|
{
|
|
/**************************************
|
|
*
|
|
* h a s h
|
|
*
|
|
**************************************
|
|
*
|
|
* Functional description
|
|
* Returns the hash function of a string.
|
|
*
|
|
**************************************/
|
|
int value;
|
|
SCHAR c;
|
|
|
|
/* It is OK to not Internationalize this function as it is for
|
|
internal optimization of symbol lookup */
|
|
|
|
value = 0;
|
|
|
|
while ( (c = *string++) )
|
|
value = (value << 1) + UPPER7(c);
|
|
|
|
return ((value >= 0) ? value : -value) % HASH_SIZE;
|
|
}
|
|
|
|
|
|
} // extern "C"
|