Source/modules/encoding/TextDecoder.cpp

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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#include "config.h"

#include "modules/encoding/TextDecoder.h"

#include "bindings/v8/ExceptionState.h"
#include "core/dom/ExceptionCode.h"
#include "wtf/text/TextEncodingRegistry.h"

namespace WebCore {

PassRefPtr<TextDecoder> TextDecoder::create(const String& label, const Dictionary& options, ExceptionState& es)
{
    const String& encodingLabel = label.isNull() ? String("utf-8") : label;

    WTF::TextEncoding encoding(encodingLabel);
    if (!encoding.isValid()) {
        es.throwTypeError();
        return 0;
    }

    bool fatal = false;
    options.get("fatal", fatal);

    return adoptRef(new TextDecoder(encoding.name(), fatal));
}


TextDecoder::TextDecoder(const String& encoding, bool fatal)
    : m_encoding(encoding)
    , m_codec(newTextCodec(m_encoding))
    , m_fatal(fatal)
    , m_bomSeen(false)
{
}

TextDecoder::~TextDecoder()
{
}

String TextDecoder::encoding() const
{
    String name = String(m_encoding.name()).lower();
    // Where possible, encoding aliases should be handled by changes to Chromium's ICU or Blink's WTF.
    // The same codec is used, but WTF maintains a different name/identity for these.
    if (name == "iso-8859-1" || name == "us-ascii")
        return "windows-1252";
    return name;
}

String TextDecoder::decode(ArrayBufferView* input, const Dictionary& options, ExceptionState& es)
{
    bool stream = false;
    options.get("stream", stream);

    const char* start = input ? static_cast<const char*>(input->baseAddress()) : 0;
    size_t length = input ? input->byteLength() : 0;

    bool flush = !stream;

    // FIXME: Not all TextCodec implementations handle |flush| - notably TextCodecUTF16
    // ignores it and never flushes!

    bool sawError = false;
    String s = m_codec->decode(start, length, flush, m_fatal, sawError);

    if (m_fatal && sawError) {
        es.throwDOMException(EncodingError, "The encoded data was not valid.");
        return String();
    }

    if (!m_bomSeen && !s.isEmpty()) {
        m_bomSeen = true;
        String name(m_encoding.name());
        if ((name == "UTF-8" || name == "UTF-16LE" || name == "UTF-16BE") && s[0] == 0xFEFF)
            s.remove(0);
    }

    if (flush)
        m_bomSeen = false;

    return s;
}

} // namespace WebCore