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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:
BufferedLineReader()48     BufferedLineReader()
49         : m_endOfStream(false)
50         , m_maybeSkipLF(false) { }
51 
52     // Append data to the internal buffer.
append(const String & data)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.
setEndOfStream()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.
isAtEndOfStream()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|.
scanCharacter(UChar 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