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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 #include "core/platform/graphics/skia/SkiaSharedBufferStream.h"
     33 
     34 #include "third_party/skia/include/core/SkStream.h"
     35 #include "core/platform/SharedBuffer.h"
     36 #include <algorithm>
     37 #include <cstring>
     38 
     39 namespace WebCore {
     40 
     41 size_t SkiaSharedBufferStream::read(void* buffer, size_t bytesRequested)
     42 {
     43     const size_t bytesLeft = m_buffer->size() - m_offset;
     44     const size_t bytesToConsume = std::min(bytesLeft, bytesRequested);
     45 
     46     if (buffer) {
     47         char* byteBuffer = reinterpret_cast<char*>(buffer);
     48         unsigned byteOffset = m_offset;
     49         unsigned bytesLeftToConsume = bytesToConsume;
     50         while (bytesLeftToConsume > 0) {
     51             const char* segment;
     52             unsigned bytesInSegment = m_buffer->getSomeData(segment, byteOffset);
     53             if (!bytesInSegment) {
     54                 unsigned bytesRead = bytesToConsume - bytesLeftToConsume;
     55                 m_offset += bytesRead;
     56                 return bytesRead;
     57             }
     58             unsigned bytesToCopy = std::min(bytesInSegment, bytesLeftToConsume);
     59             std::memcpy(byteBuffer, segment, bytesToCopy);
     60             bytesLeftToConsume -= bytesToCopy;
     61             byteBuffer += bytesToCopy;
     62             byteOffset += bytesToCopy;
     63         }
     64     }
     65     m_offset += bytesToConsume;
     66     return bytesToConsume;
     67 }
     68 
     69 bool SkiaSharedBufferStream::isAtEnd() const
     70 {
     71     return this->getLength() == m_offset;
     72 }
     73 
     74 bool SkiaSharedBufferStream::rewind()
     75 {
     76     m_offset = 0;
     77     return true;
     78 }
     79 
     80 SkiaSharedBufferStream* SkiaSharedBufferStream::duplicate() const
     81 {
     82     return new SkiaSharedBufferStream(m_buffer);
     83 }
     84 
     85 size_t SkiaSharedBufferStream::getPosition() const
     86 {
     87     return m_offset;
     88 }
     89 
     90 bool SkiaSharedBufferStream::seek(size_t position)
     91 {
     92     m_offset = std::min(position, static_cast<size_t>(m_buffer->size()));
     93     return true;
     94 }
     95 
     96 bool SkiaSharedBufferStream::move(long offset)
     97 {
     98     return this->seek(m_offset + offset);
     99 }
    100 
    101 SkiaSharedBufferStream* SkiaSharedBufferStream::fork() const
    102 {
    103     SkiaSharedBufferStream* that = this->duplicate();
    104     that->m_offset = this->m_offset;
    105     return that;
    106 }
    107 
    108 size_t SkiaSharedBufferStream::getLength() const
    109 {
    110     return m_buffer->size();
    111 }
    112 
    113 const void* SkiaSharedBufferStream::getMemoryBase()
    114 {
    115     const char* segment;
    116     unsigned bytesInSegment = m_buffer->getSomeData(segment);
    117     return (bytesInSegment != m_buffer->size()) ? 0 : segment;
    118 }
    119 
    120 }
    121