Move Source/WTF/wtf to Source/wtf

Source/WTF/wtf/text/StringHash.h

-/*
- * Copyright (C) 2006, 2007, 2008, 2012, 2013 Apple Inc. All rights reserved
- * Copyright (C) Research In Motion Limited 2009. All rights reserved.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public License
- * along with this library; see the file COPYING.LIB.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- *
- */
-
-#ifndef StringHash_h
-#define StringHash_h
-
-#include <wtf/text/AtomicString.h>
-#include <wtf/HashTraits.h>
-#include <wtf/StringHasher.h>
-
-namespace WTF {
-
-    inline bool HashTraits<String>::isEmptyValue(const String& value)
-    {
-        return value.isNull();
-    }
-
-    // The hash() functions on StringHash and CaseFoldingHash do not support
-    // null strings. get(), contains(), and add() on HashMap<String,..., StringHash>
-    // cause a null-pointer dereference when passed null strings.
-
-    // FIXME: We should really figure out a way to put the computeHash function that's
-    // currently a member function of StringImpl into this file so we can be a little
-    // closer to having all the nearly-identical hash functions in one place.
-
-    struct StringHash {
-        static unsigned hash(StringImpl* key) { return key->hash(); }
-        static inline bool equal(const StringImpl* a, const StringImpl* b)
-        {
-            return equalNonNull(a, b);
-        }
-
-        static unsigned hash(const RefPtr<StringImpl>& key) { return key->hash(); }
-        static bool equal(const RefPtr<StringImpl>& a, const RefPtr<StringImpl>& b)
-        {
-            return equal(a.get(), b.get());
-        }
-
-        static unsigned hash(const String& key) { return key.impl()->hash(); }
-        static bool equal(const String& a, const String& b)
-        {
-            return equal(a.impl(), b.impl());
-        }
-
-        static const bool safeToCompareToEmptyOrDeleted = false;
-    };
-
-    class CaseFoldingHash {
-    public:
-        template<typename T> static inline UChar foldCase(T ch)
-        {
-            return WTF::Unicode::foldCase(ch);
-        }
-
-        static unsigned hash(const UChar* data, unsigned length)
-        {
-            return StringHasher::computeHashAndMaskTop8Bits<UChar, foldCase<UChar> >(data, length);
-        }
-
-        static unsigned hash(StringImpl* str)
-        {
-            if (str->is8Bit())
-                return hash(str->characters8(), str->length());
-            return hash(str->characters16(), str->length());
-        }
-
-        static unsigned hash(const LChar* data, unsigned length)
-        {
-            return StringHasher::computeHashAndMaskTop8Bits<LChar, foldCase<LChar> >(data, length);
-        }
-
-        static inline unsigned hash(const char* data, unsigned length)
-        {
-            return CaseFoldingHash::hash(reinterpret_cast<const LChar*>(data), length);
-        }
-        
-        static inline bool equal(const StringImpl* a, const StringImpl* b)
-        {
-            return equalIgnoringCaseNonNull(a, b);
-        }
-
-        static unsigned hash(const RefPtr<StringImpl>& key) 
-        {
-            return hash(key.get());
-        }
-
-        static bool equal(const RefPtr<StringImpl>& a, const RefPtr<StringImpl>& b)
-        {
-            return equal(a.get(), b.get());
-        }
-
-        static unsigned hash(const String& key)
-        {
-            return hash(key.impl());
-        }
-        static unsigned hash(const AtomicString& key)
-        {
-            return hash(key.impl());
-        }
-        static bool equal(const String& a, const String& b)
-        {
-            return equal(a.impl(), b.impl());
-        }
-        static bool equal(const AtomicString& a, const AtomicString& b)
-        {
-            return (a == b) || equal(a.impl(), b.impl());
-        }
-
-        static const bool safeToCompareToEmptyOrDeleted = false;
-    };
-
-    // This hash can be used in cases where the key is a hash of a string, but we don't
-    // want to store the string. It's not really specific to string hashing, but all our
-    // current uses of it are for strings.
-    struct AlreadyHashed : IntHash<unsigned> {
-        static unsigned hash(unsigned key) { return key; }
-
-        // To use a hash value as a key for a hash table, we need to eliminate the
-        // "deleted" value, which is negative one. That could be done by changing
-        // the string hash function to never generate negative one, but this works
-        // and is still relatively efficient.
-        static unsigned avoidDeletedValue(unsigned hash)
-        {
-            ASSERT(hash);
-            unsigned newHash = hash | (!(hash + 1) << 31);
-            ASSERT(newHash);
-            ASSERT(newHash != 0xFFFFFFFF);
-            return newHash;
-        }
-    };
-
-}
-
-using WTF::AlreadyHashed;
-using WTF::CaseFoldingHash;
-using WTF::StringHash;
-
-#endif