Source/WebCore/html/track/BufferedLineReader.h

/*
 * Copyright (C) 2013, Opera Software ASA. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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 THE COPYRIGHT
 * OWNER 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.
 */

#pragma once

#include "SegmentedString.h"
#include <wtf/text/StringBuilder.h>

namespace WebCore {

// Line collection helper for the WebVTT Parser.
//
// Converts a stream of data (== a sequence of Strings) into a set of
// lines. CR, LR or CRLF are considered line breaks. Normalizes NULs (U+0000)
// to 'REPLACEMENT CHARACTER' (U+FFFD) and does not return the line breaks as
// part of the result.
class BufferedLineReader {
    WTF_MAKE_NONCOPYABLE(BufferedLineReader);
public:
    BufferedLineReader() = default;
    void reset();

    void append(String&& data)
    {
        ASSERT(!m_endOfStream);
        m_buffer.append(WTFMove(data));
    }

    void appendEndOfStream() { m_endOfStream = true; }
    bool isAtEndOfStream() const { return m_endOfStream && m_buffer.isEmpty(); }

    std::optional<String> nextLine();

private:
    SegmentedString m_buffer;
    StringBuilder m_lineBuffer;
    bool m_endOfStream { false };
    bool m_maybeSkipLF { false };
};

inline void BufferedLineReader::reset()
{
    m_buffer.clear();
    m_lineBuffer.clear();
    m_endOfStream = false;
    m_maybeSkipLF = false;
}

} // namespace WebCore