X-Git-Url: https://git.saurik.com/apple/javascriptcore.git/blobdiff_plain/1df5f87f1309a8daa30dabdee855f48ae40d14ab..6fe7ccc865dc7d7541b93c5bcaf6368d2c98a174:/wtf/text/StringHash.h diff --git a/wtf/text/StringHash.h b/wtf/text/StringHash.h deleted file mode 100644 index c47c1d8..0000000 --- a/wtf/text/StringHash.h +++ /dev/null @@ -1,190 +0,0 @@ -/* - * Copyright (C) 2006, 2007, 2008 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 "AtomicString.h" -#include "WTFString.h" -#include -#include -#include -#include - -namespace WTF { - - // The hash() functions on StringHash and CaseFoldingHash do not support - // null strings. get(), contains(), and add() on HashMap - // 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 bool equal(const StringImpl* a, const StringImpl* b) - { - if (a == b) - return true; - if (!a || !b) - return false; - - unsigned aLength = a->length(); - unsigned bLength = b->length(); - if (aLength != bLength) - return false; - - // FIXME: perhaps we should have a more abstract macro that indicates when - // going 4 bytes at a time is unsafe -#if CPU(ARM) || CPU(SH4) || CPU(MIPS) - const UChar* aChars = a->characters(); - const UChar* bChars = b->characters(); - for (unsigned i = 0; i != aLength; ++i) { - if (*aChars++ != *bChars++) - return false; - } - return true; -#else - /* Do it 4-bytes-at-a-time on architectures where it's safe */ - const uint32_t* aChars = reinterpret_cast(a->characters()); - const uint32_t* bChars = reinterpret_cast(b->characters()); - - unsigned halfLength = aLength >> 1; - for (unsigned i = 0; i != halfLength; ++i) - if (*aChars++ != *bChars++) - return false; - - if (aLength & 1 && *reinterpret_cast(aChars) != *reinterpret_cast(bChars)) - return false; - - return true; -#endif - } - - static unsigned hash(const RefPtr& key) { return key->hash(); } - static bool equal(const RefPtr& a, const RefPtr& 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 static inline UChar foldCase(T ch) - { - return WTF::Unicode::foldCase(ch); - } - - static unsigned hash(const UChar* data, unsigned length) - { - return StringHasher::computeHash >(data, length); - } - - static unsigned hash(StringImpl* str) - { - return hash(str->characters(), str->length()); - } - - static unsigned hash(const char* data, unsigned length) - { - return StringHasher::computeHash >(data, length); - } - - static bool equal(const StringImpl* a, const StringImpl* b) - { - if (a == b) - return true; - if (!a || !b) - return false; - unsigned length = a->length(); - if (length != b->length()) - return false; - return WTF::Unicode::umemcasecmp(a->characters(), b->characters(), length) == 0; - } - - static unsigned hash(const RefPtr& key) - { - return hash(key.get()); - } - - static bool equal(const RefPtr& a, const RefPtr& 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 { - 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; - } - }; - - template<> struct HashTraits : SimpleClassHashTraits { }; - -} - -using WTF::StringHash; -using WTF::CaseFoldingHash; -using WTF::AlreadyHashed; - -#endif