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      1 /*
      2  * Copyright (C) 2014 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 #include "core/xml/parser/SharedBufferReader.h"
     33 
     34 #include "platform/SharedBuffer.h"
     35 #include "wtf/PassRefPtr.h"
     36 #include "wtf/RefPtr.h"
     37 
     38 #include <algorithm>
     39 #include <cstring>
     40 
     41 namespace blink {
     42 
     43 SharedBufferReader::SharedBufferReader(PassRefPtr<SharedBuffer> buffer)
     44     : m_buffer(buffer)
     45     , m_currentOffset(0)
     46 {
     47 }
     48 
     49 SharedBufferReader::~SharedBufferReader()
     50 {
     51 }
     52 
     53 int SharedBufferReader::readData(char* outputBuffer, unsigned askedToRead)
     54 {
     55     if (!m_buffer || m_currentOffset > m_buffer->size())
     56         return 0;
     57 
     58     unsigned bytesCopied = 0;
     59     unsigned bytesLeft = m_buffer->size() - m_currentOffset;
     60     unsigned lenToCopy = std::min(askedToRead, bytesLeft);
     61 
     62     while (bytesCopied < lenToCopy) {
     63         const char* data;
     64         unsigned segmentSize = m_buffer->getSomeData(data, m_currentOffset);
     65         if (!segmentSize)
     66             break;
     67 
     68         segmentSize = std::min(segmentSize, lenToCopy - bytesCopied);
     69         memcpy(outputBuffer + bytesCopied, data, segmentSize);
     70         bytesCopied += segmentSize;
     71         m_currentOffset += segmentSize;
     72     }
     73 
     74     return bytesCopied;
     75 }
     76 
     77 } // namespace blink
     78