kjs/lookup.cpp

   1 // -*- c-basic-offset: 2 -*-
   2 /*
   3  *  This file is part of the KDE libraries
   4  *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
   5  *  Copyright (C) 2003 Apple Computer, Inc.
   6  *
   7  *  This library is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU Lesser General Public
   9  *  License as published by the Free Software Foundation; either
  10  *  version 2 of the License, or (at your option) any later version.
  11  *
  12  *  This library is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *  Lesser General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Lesser General Public
  18  *  License along with this library; if not, write to the Free Software
  19  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  20  *
  21  */
  22
  23 #include "lookup.h"
  24
  25 #include <config.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28
  29 #include <wtf/Assertions.h>
  30
  31 using namespace KJS;
  32
  33 static inline bool keysMatch(const UChar *c, unsigned len, const char *s)
  34 {
  35   const char* end = s + len;
  36   for (; s != end; c++, s++)
  37     if (c->uc != (unsigned char)*s)
  38       return false;
  39   return *s == 0;
  40 }
  41
  42 static inline const HashEntry* findEntry(const struct HashTable *table, unsigned int hash,
  43                                          const UChar *c, unsigned int len )
  44 {
  45 #ifndef NDEBUG
  46   if (table->type != 2) {
  47     fprintf(stderr, "KJS: Unknown hash table version.\n");
  48     return 0;
  49   }
  50 #endif
  51   ASSERT(table->hashSize != 0);
  52
  53   hash %= table->hashSize;
  54
  55   const HashEntry *e = &table->entries[hash];
  56
  57   // empty bucket ?
  58   if (!e->s)
  59     return 0;
  60
  61   do {
  62     // compare strings
  63     if (keysMatch(c, len, e->s))
  64       return e;
  65
  66     // try next bucket
  67     e = e->next;
  68   } while (e);
  69   return 0;
  70 }
  71
  72 const HashEntry* Lookup::findEntry(const struct HashTable *table,
  73                                    const Identifier &s )
  74 {
  75   const HashEntry* entry = ::findEntry(table, s.ustring().rep()->hash(), s.data(), s.size());
  76   return entry;
  77 }
  78
  79 int Lookup::find(const struct HashTable *table,
  80                  const UChar *c, unsigned int len)
  81 {
  82   const HashEntry *entry = ::findEntry(table, UString::Rep::computeHash(c, len), c, len);
  83   if (entry)
  84     return entry->value;
  85   return -1;
  86 }
  87
  88 int Lookup::find(const struct HashTable *table, const Identifier &s)
  89 {
  90   //printf("looking for:%s\n", s.ascii());
  91   const HashEntry *entry = ::findEntry(table, s.ustring().rep()->hash(), s.data(), s.size());
  92   if (entry)
  93     return entry->value;
  94   return -1;
  95 }