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      1 /*
      2  * Copyright (C) 2013, Opera Software ASA. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef BufferedLineReader_h
     32 #define BufferedLineReader_h
     33 
     34 #include "platform/text/SegmentedString.h"
     35 #include "wtf/text/StringBuilder.h"
     36 
     37 namespace WebCore {
     38 
     39 // Line collection helper for the WebVTT Parser.
     40 //
     41 // Converts a stream of data (== a sequence of Strings) into a set of
     42 // lines. CR, LR or CRLF are considered linebreaks. Normalizes NULs (U+0000)
     43 // to 'REPLACEMENT CHARACTER' (U+FFFD) and does not return the linebreaks as
     44 // part of the result.
     45 class BufferedLineReader {
     46     WTF_MAKE_NONCOPYABLE(BufferedLineReader);
     47 public:
     48     BufferedLineReader()
     49         : m_endOfStream(false)
     50         , m_maybeSkipLF(false) { }
     51 
     52     // Append data to the internal buffer.
     53     void append(const String& data)
     54     {
     55         ASSERT(!m_endOfStream);
     56         m_buffer.append(SegmentedString(data));
     57     }
     58 
     59     // Indicate that no more data will be appended. This will cause any
     60     // potentially "unterminated" line to be returned from getLine.
     61     void setEndOfStream() { m_endOfStream = true; }
     62 
     63     // Attempt to read a line from the internal buffer (fed via append).
     64     // If successful, true is returned and |line| is set to the line that was
     65     // read. If no line could be read false is returned.
     66     bool getLine(String& line);
     67 
     68     // Returns true if EOS has been reached proper.
     69     bool isAtEndOfStream() const { return m_endOfStream && m_buffer.isEmpty(); }
     70 
     71 private:
     72     // Consume the next character the buffer if it is the character |c|.
     73     void scanCharacter(UChar c)
     74     {
     75         ASSERT(!m_buffer.isEmpty());
     76         if (m_buffer.currentChar() == c)
     77             m_buffer.advance();
     78     }
     79 
     80     SegmentedString m_buffer;
     81     StringBuilder m_lineBuffer;
     82     bool m_endOfStream;
     83     bool m_maybeSkipLF;
     84 };
     85 
     86 } // namespace WebCore
     87 
     88 #endif
     89