# kjs Library API Documentation

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# lookup.cpp

    00001 // -*- c-basic-offset: 2 -*-
    00002 /*
    00003  *  This file is part of the KDE libraries
    00004  *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
    00005  *  Copyright (C) 2003 Apple Computer, Inc.
    00006  *
    00007  *  This library is free software; you can redistribute it and/or
    00008  *  modify it under the terms of the GNU Lesser General Public
    00009  *  License as published by the Free Software Foundation; either
    00010  *  version 2 of the License, or (at your option) any later version.
    00011  *
    00012  *  This library is distributed in the hope that it will be useful,
    00013  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    00015  *  Lesser General Public License for more details.
    00016  *
    00017  *  You should have received a copy of the GNU Lesser General Public
    00018  *  License along with this library; if not, write to the Free Software
    00019  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    00020  *
    00021  */
    00022
    00023 #include <stdio.h>
    00024 #include <string.h>
    00025
    00026 #include "lookup.h"
    00027
    00028 #ifdef HAVE_CONFIG_H
    00029 #include <config.h>
    00030 #endif
    00031
    00032 using namespace KJS;
    00033
    00034 static bool keysMatch(const UChar *c, unsigned len, const char *s)
    00035 {
    00036   for (unsigned i = 0; i != len; i++, c++, s++)
    00037     if (c->uc != (unsigned char)*s)
    00038       return false;
    00039   return *s == 0;
    00040 }
    00041
    00042 const HashEntry* Lookup::findEntry( const struct HashTable *table,
    00043                               const UChar *c, unsigned int len )
    00044 {
    00045 #ifndef NDEBUG
    00046   if (table->type != 2) {
    00047     fprintf(stderr, "KJS: Unknown hash table version.\n");
    00048     return 0;
    00049   }
    00050 #endif
    00051
    00052   int h = hash(c, len) % table->hashSize;
    00053   const HashEntry *e = &table->entries[h];
    00054
    00055   // empty bucket ?
    00056   if (!e->soffset)
    00057     return 0;
    00058
    00059   while(1) {
    00060     // compare strings
    00061     if (keysMatch(c, len, &table->sbase[e->soffset]))
    00062       return e;
    00063     // try next bucket
    00064     if(e->next < 0) break;
    00065
    00066     e = &table->entries[e->next];
    00067   }
    00068
    00069   return 0;
    00070 }
    00071
    00072 const HashEntry* Lookup::findEntry( const struct HashTable *table,
    00073                                 const Identifier &s )
    00074 {
    00075   return findEntry( table, s.data(), s.size() );
    00076 }
    00077
    00078 int Lookup::find(const struct HashTable *table,
    00079          const UChar *c, unsigned int len)
    00080 {
    00081   const HashEntry *entry = findEntry( table, c, len );
    00082   if (entry)
    00083     return entry->value;
    00084   return -1;
    00085 }
    00086
    00087 int Lookup::find(const struct HashTable *table, const Identifier &s)
    00088 {
    00089   return find(table, s.data(), s.size());
    00090 }
    00091
    00092 unsigned int Lookup::hash(const UChar *c, unsigned int len)
    00093 {
    00094   unsigned int val = 0;
    00095   // ignoring higher byte
    00096   for (unsigned int i = 0; i < len; i++, c++)
    00097     val += c->low();
    00098
    00099   return val;
    00100 }
    00101
    00102 unsigned int Lookup::hash(const Identifier &key)
    00103 {
    00104   return hash(key.data(), key.size());
    00105 }
    00106
    00107 unsigned int Lookup::hash(const char *s)
    00108 {
    00109   unsigned int val = 0;
    00110   while (*s)
    00111     val += *s++;
    00112
    00113   return val;
    00114 }

This file is part of the documentation for kjs Library Version 3.4.1.
Documentation copyright © 1996-2004 the KDE developers.
Generated on Sat Jun 11 20:23:06 2005 by doxygen 1.4.1 written by Dimitri van Heesch, © 1997-2003