1/*
2 * Copyright (C) 2013 Google Inc. 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#include "config.h"
32
33#include "modules/encoding/TextDecoder.h"
34
35#include "bindings/core/v8/ExceptionState.h"
36#include "core/dom/ExceptionCode.h"
37#include "wtf/StringExtras.h"
38#include "wtf/text/TextEncodingRegistry.h"
39
40namespace blink {
41
42TextDecoder* TextDecoder::create(const String& label, const TextDecoderOptions& options, ExceptionState& exceptionState)
43{
44    WTF::TextEncoding encoding(label);
45    // The replacement encoding is not valid, but the Encoding API also
46    // rejects aliases of the replacement encoding.
47    if (!encoding.isValid() || !strcasecmp(encoding.name(), "replacement")) {
48        exceptionState.throwTypeError("The encoding label provided ('" + label + "') is invalid.");
49        return 0;
50    }
51
52    return new TextDecoder(encoding, options.fatal(), options.ignoreBOM());
53}
54
55
56TextDecoder::TextDecoder(const WTF::TextEncoding& encoding, bool fatal, bool ignoreBOM)
57    : m_encoding(encoding)
58    , m_codec(newTextCodec(encoding))
59    , m_fatal(fatal)
60    , m_ignoreBOM(ignoreBOM)
61    , m_bomSeen(false)
62{
63}
64
65TextDecoder::~TextDecoder()
66{
67}
68
69String TextDecoder::encoding() const
70{
71    String name = String(m_encoding.name()).lower();
72    // Where possible, encoding aliases should be handled by changes to Chromium's ICU or Blink's WTF.
73    // The same codec is used, but WTF maintains a different name/identity for these.
74    if (name == "iso-8859-1" || name == "us-ascii")
75        return "windows-1252";
76    return name;
77}
78
79String TextDecoder::decode(ArrayBufferView* input, const TextDecodeOptions& options, ExceptionState& exceptionState)
80{
81    const char* start = input ? static_cast<const char*>(input->baseAddress()) : 0;
82    size_t length = input ? input->byteLength() : 0;
83
84    WTF::FlushBehavior flush = options.stream() ? WTF::DoNotFlush : WTF::DataEOF;
85
86    bool sawError = false;
87    String s = m_codec->decode(start, length, flush, m_fatal, sawError);
88
89    if (m_fatal && sawError) {
90        exceptionState.throwDOMException(EncodingError, "The encoded data was not valid.");
91        return String();
92    }
93
94    if (!m_ignoreBOM && !m_bomSeen && !s.isEmpty()) {
95        m_bomSeen = true;
96        String name(m_encoding.name());
97        if ((name == "UTF-8" || name == "UTF-16LE" || name == "UTF-16BE") && s[0] == 0xFEFF)
98            s.remove(0);
99    }
100
101    if (flush)
102        m_bomSeen = false;
103
104    return s;
105}
106
107String TextDecoder::decode(ExceptionState& exceptionState)
108{
109    TextDecodeOptions* options = TextDecodeOptions::create();
110    return decode(0, *options, exceptionState);
111}
112
113} // namespace blink
114