Source/core/editing/iterators/SearchBuffer.h

/*
 * Copyright (C) 2004, 2006, 2009 Apple 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,
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 */

#ifndef SearchBuffer_h
#define SearchBuffer_h

#include "core/CoreExport.h"
#include "core/editing/EphemeralRange.h"
#include "core/editing/FindOptions.h"
#include "wtf/Allocator.h"
#include "wtf/Vector.h"

namespace blink {

// Buffer that knows how to compare with a search target.
// Keeps enough of the previous text to be able to search in the future, but no
// more. Non-breaking spaces are always equal to normal spaces. Case folding is
// also done if the CaseInsensitive option is specified. Matches are further
// filtered if the AtWordStarts option is specified, although some matches
// inside a word are permitted if TreatMedialCapitalAsWordStart is specified as
// well.
class SearchBuffer {
    STACK_ALLOCATED();
    WTF_MAKE_NONCOPYABLE(SearchBuffer);
public:
    SearchBuffer(const String& target, FindOptions);
    ~SearchBuffer();

    // Returns number of characters appended; guaranteed to be in the range
    // [1, length].
    template<typename CharType>
    void append(const CharType*, size_t length);
    size_t numberOfCharactersJustAppended() const { return m_numberOfCharactersJustAppended; }

    bool needsMoreContext() const;
    void prependContext(const UChar*, size_t length);
    void reachedBreak();

    // Result is the size in characters of what was found.
    // And <startOffset> is the number of characters back to the start of what
    // was found.
    size_t search(size_t& startOffset);
    bool atBreak() const;

private:
    bool isBadMatch(const UChar*, size_t length) const;
    bool isWordStartMatch(size_t start, size_t length) const;

    Vector<UChar> m_target;
    FindOptions m_options;

    Vector<UChar> m_buffer;
    size_t m_overlap;
    size_t m_prefixLength;
    size_t m_numberOfCharactersJustAppended;
    bool m_atBreak;
    bool m_needsMoreContext;

    bool m_targetRequiresKanaWorkaround;
    Vector<UChar> m_normalizedTarget;
    mutable Vector<UChar> m_normalizedMatch;
};

CORE_EXPORT EphemeralRange findPlainText(const EphemeralRange& inputRange, const String&, FindOptions);
CORE_EXPORT EphemeralRangeInComposedTree findPlainText(const EphemeralRangeInComposedTree& inputRange, const String&, FindOptions);

} // namespace blink

#endif // SearchBuffer_h