/*

 * Copyright (C) 2008 Google Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#ifndef LinkHash_h

#define LinkHash_h

#include "StringHash.h"

namespace WebCore {

class AtomicString;

class KURL;

typedef uint64_t LinkHash;

// Use the low 32-bits of the 64-bit LinkHash as the key for HashSets.

struct LinkHashHash {

    static unsigned hash(LinkHash key) { return static_cast<unsigned>(key); }

    static bool equal(LinkHash a, LinkHash b) { return a == b; }

    static const bool safeToCompareToEmptyOrDeleted = true;

    // See AlreadyHashed::avoidDeletedValue.

    static unsigned avoidDeletedValue(LinkHash hash64)

    {

        ASSERT(hash64);

        unsigned hash = static_cast<unsigned>(hash64);

        unsigned newHash = hash | (!(hash + 1) << 31);

        ASSERT(newHash);

        ASSERT(newHash != 0xFFFFFFFF);

        return newHash;

    }

};

// Returns the has of the string that will be used for visited link coloring.

LinkHash visitedLinkHash(const UChar* url, unsigned length);

// Resolves the potentially relative URL "attributeURL" relative to the given

// base URL, and returns the hash of the string that will be used for visited

// link coloring. It will return the special value of 0 if attributeURL does not

// look like a relative URL.

LinkHash visitedLinkHash(const KURL& base, const AtomicString& attributeURL);

// Resolves the potentially relative URL "attributeURL" relative to the given

// base URL, and returns the hash of the string that will be used for visited.

// It will return an empty Vector in case of errors.

void visitedURL(const KURL& base, const AtomicString& attributeURL, Vector<UChar, 512>&);

}  // namespace WebCore

#endif  // LinkHash_h