// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "sky/engine/core/css/parser/MediaQueryInputStream.h"

namespace blink {

MediaQueryInputStream::MediaQueryInputStream(String input)
    : m_offset(0)
    , m_string(input)
{
}

UChar MediaQueryInputStream::peek(unsigned lookaheadOffset)
{
    ASSERT((m_offset + lookaheadOffset) <= maxLength());
    if ((m_offset + lookaheadOffset) >= m_string.length())
        return kEndOfFileMarker;
    return m_string[m_offset + lookaheadOffset];
}

void MediaQueryInputStream::advance(unsigned offset)
{
    ASSERT(m_offset + offset <= maxLength());
    m_offset += offset;
}

void MediaQueryInputStream::pushBack(UChar cc)
{
    --m_offset;
    ASSERT(nextInputChar() == cc);
}

unsigned long long MediaQueryInputStream::getUInt(unsigned start, unsigned end)
{
    ASSERT(start <= end && ((m_offset + end) <= m_string.length()));
    bool isResultOK = false;
    unsigned long long result = 0;
    if (start < end) {
        if (m_string.is8Bit())
            result = charactersToUInt64Strict(m_string.characters8() + m_offset + start, end - start, &isResultOK);
        else
            result = charactersToUInt64Strict(m_string.characters16() + m_offset + start, end - start, &isResultOK);
    }
    return isResultOK ? result : 0;
}

double MediaQueryInputStream::getDouble(unsigned start, unsigned end)
{
    ASSERT(start <= end && ((m_offset + end) <= m_string.length()));
    bool isResultOK = false;
    double result = 0.0;
    if (start < end) {
        if (m_string.is8Bit())
            result = charactersToDouble(m_string.characters8() + m_offset + start, end - start, &isResultOK);
        else
            result = charactersToDouble(m_string.characters16() + m_offset + start, end - start, &isResultOK);
    }
    return isResultOK ? result : 0.0;
}

} // namespace blink