106 lines
2.6 KiB
C++
106 lines
2.6 KiB
C++
/*
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Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License, version 2.0, for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/* SIMPLE HASH TABLE. Maps a null-terminated string to a pointer.
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Creates and manages its own copy of the string.
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*/
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#include <stdio.h>
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#include <string.h>
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template<typename T> class LookupTable {
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public:
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int elements;
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bool do_free_values;
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LookupTable(int sz = 128) :
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elements(0),
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do_free_values(false),
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size(sz),
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symtab(new Entry *[sz])
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{
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for(int i = 0 ; i < size ; i++)
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symtab[i] = 0;
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}
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~LookupTable() {
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for(int i = 0 ; i < size ; i++) {
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Entry *sym = symtab[i];
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while(sym) {
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if(do_free_values) free((void *) sym->value);
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Entry *next = sym->next;
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delete sym;
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sym = next;
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}
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}
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delete[] symtab;
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}
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T * find(const char *name) {
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Uint32 h = do_hash(name) % size;
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for(Entry *sym = symtab[h] ; sym != 0 ; sym = sym->next)
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if(strcmp(name, sym->key) == 0)
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return sym->value;
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return 0;
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}
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void insert(const char *name, T * value) {
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Uint32 h = do_hash(name) % size;
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Entry *sym = new Entry(name, value);
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sym->next = symtab[h];
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symtab[h] = sym;
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elements++;
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}
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private:
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class Entry {
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public:
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char *key;
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T * value;
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Entry *next;
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Entry(const char *name, T * val) {
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key = strdup(name);
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value = val;
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}
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~Entry() {
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free(key);
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}
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};
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int size;
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Entry ** symtab;
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Uint32 do_hash(const char *string) {
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Uint32 h = 0;
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for(const char *s = string; *s != 0; s++) h = 37 * h + *s;
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return h;
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}
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};
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