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      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/v8/ExceptionState.h"
     36 #include "core/dom/ExceptionCode.h"
     37 #include "wtf/StringExtras.h"
     38 #include "wtf/text/TextEncodingRegistry.h"
     39 
     40 namespace WebCore {
     41 
     42 TextDecoder* TextDecoder::create(const String& label, const Dictionary& options, ExceptionState& exceptionState)
     43 {
     44     const String& encodingLabel = label.isNull() ? String("utf-8") : label;
     45 
     46     WTF::TextEncoding encoding(encodingLabel);
     47     // The replacement encoding is not valid, but the Encoding API also
     48     // rejects aliases of the replacement encoding.
     49     if (!encoding.isValid() || !strcasecmp(encoding.name(), "replacement")) {
     50         exceptionState.throwTypeError("The encoding label provided ('" + encodingLabel + "') is invalid.");
     51         return 0;
     52     }
     53 
     54     bool fatal = false;
     55     options.get("fatal", fatal);
     56 
     57     bool ignoreBOM = false;
     58     options.get("ignoreBOM", ignoreBOM);
     59 
     60     return new TextDecoder(encoding, fatal, ignoreBOM);
     61 }
     62 
     63 
     64 TextDecoder::TextDecoder(const WTF::TextEncoding& encoding, bool fatal, bool ignoreBOM)
     65     : m_encoding(encoding)
     66     , m_codec(newTextCodec(encoding))
     67     , m_fatal(fatal)
     68     , m_ignoreBOM(ignoreBOM)
     69     , m_bomSeen(false)
     70 {
     71 }
     72 
     73 TextDecoder::~TextDecoder()
     74 {
     75 }
     76 
     77 String TextDecoder::encoding() const
     78 {
     79     String name = String(m_encoding.name()).lower();
     80     // Where possible, encoding aliases should be handled by changes to Chromium's ICU or Blink's WTF.
     81     // The same codec is used, but WTF maintains a different name/identity for these.
     82     if (name == "iso-8859-1" || name == "us-ascii")
     83         return "windows-1252";
     84     return name;
     85 }
     86 
     87 String TextDecoder::decode(ArrayBufferView* input, const Dictionary& options, ExceptionState& exceptionState)
     88 {
     89     bool stream = false;
     90     options.get("stream", stream);
     91 
     92     const char* start = input ? static_cast<const char*>(input->baseAddress()) : 0;
     93     size_t length = input ? input->byteLength() : 0;
     94 
     95     WTF::FlushBehavior flush = stream ? WTF::DoNotFlush : WTF::DataEOF;
     96 
     97     bool sawError = false;
     98     String s = m_codec->decode(start, length, flush, m_fatal, sawError);
     99 
    100     if (m_fatal && sawError) {
    101         exceptionState.throwDOMException(EncodingError, "The encoded data was not valid.");
    102         return String();
    103     }
    104 
    105     if (!m_ignoreBOM && !m_bomSeen && !s.isEmpty()) {
    106         m_bomSeen = true;
    107         String name(m_encoding.name());
    108         if ((name == "UTF-8" || name == "UTF-16LE" || name == "UTF-16BE") && s[0] == 0xFEFF)
    109             s.remove(0);
    110     }
    111 
    112     if (flush)
    113         m_bomSeen = false;
    114 
    115     return s;
    116 }
    117 
    118 } // namespace WebCore
    119