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
37namespace blink {
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.
45class BufferedLineReader {
46    WTF_MAKE_NONCOPYABLE(BufferedLineReader);
47public:
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
71private:
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 blink
87
88#endif
89