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// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
#include "barcode.h"
#include "include/BC_CommonBitSource.h"
CBC_CommonBitSource::CBC_CommonBitSource(CFX_ByteArray* bytes)
{
m_bytes.Copy((*bytes));
m_bitOffset = 0;
m_byteOffset = 0;
}
CBC_CommonBitSource::~CBC_CommonBitSource()
{
}
FX_INT32 CBC_CommonBitSource::ReadBits(FX_INT32 numBits, FX_INT32 &e)
{
if (numBits < 1 || numBits > 32) {
e = BCExceptionIllegalArgument;
return 0;
}
FX_INT32 result = 0;
if (m_bitOffset > 0) {
FX_INT32 bitsLeft = 8 - m_bitOffset;
FX_INT32 toRead = numBits < bitsLeft ? numBits : bitsLeft;
FX_INT32 bitsToNotRead = bitsLeft - toRead;
FX_INT32 mask = (0xff >> (8 - toRead)) << bitsToNotRead;
result = (m_bytes[m_byteOffset] & mask) >> bitsToNotRead;
numBits -= toRead;
m_bitOffset += toRead;
if (m_bitOffset == 8) {
m_bitOffset = 0;
m_byteOffset++;
}
}
if (numBits > 0) {
while(numBits >= 8) {
result = (result << 8) | (m_bytes[m_byteOffset] & 0xff);
m_byteOffset++;
numBits -= 8;
}
if (numBits > 0) {
FX_INT32 bitsToNotRead = 8 - numBits;
FX_INT32 mask = (0xff >> bitsToNotRead) << bitsToNotRead;
result = (result << numBits) | ((m_bytes[m_byteOffset] & mask) >> bitsToNotRead);
m_bitOffset += numBits;
}
}
return result;
}
FX_INT32 CBC_CommonBitSource::Available()
{
return 8 * (m_bytes.GetSize() - m_byteOffset) - m_bitOffset;
}
FX_INT32 CBC_CommonBitSource::getByteOffset()
{
return m_byteOffset;
}
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