1 /* 2 * Copyright (C) 2012 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 #ifndef WTF_StreamBuffer_h 32 #define WTF_StreamBuffer_h 33 34 #include "wtf/Deque.h" 35 #include "wtf/PassOwnPtr.h" 36 37 namespace WTF { 38 39 template <typename T, size_t BlockSize> class StreamBuffer { 40 private: 41 typedef Vector<T> Block; 42 public: StreamBuffer()43 StreamBuffer() 44 : m_size(0) 45 , m_readOffset(0) 46 { 47 } 48 ~StreamBuffer()49 ~StreamBuffer() 50 { 51 } 52 isEmpty()53 bool isEmpty() const { return !size(); } 54 append(const T * data,size_t size)55 void append(const T* data, size_t size) 56 { 57 if (!size) 58 return; 59 60 m_size += size; 61 while (size) { 62 if (!m_buffer.size() || m_buffer.last()->size() == BlockSize) 63 m_buffer.append(adoptPtr(new Block)); 64 size_t appendSize = std::min(BlockSize - m_buffer.last()->size(), size); 65 m_buffer.last()->append(data, appendSize); 66 data += appendSize; 67 size -= appendSize; 68 } 69 } 70 71 // This function consume data in the fist block. 72 // Specified size must be less than over equal to firstBlockSize(). consume(size_t size)73 void consume(size_t size) 74 { 75 ASSERT(m_size >= size); 76 if (!m_size) 77 return; 78 79 ASSERT(m_buffer.size() > 0); 80 ASSERT(m_readOffset + size <= m_buffer.first()->size()); 81 m_readOffset += size; 82 m_size -= size; 83 if (m_readOffset >= m_buffer.first()->size()) { 84 m_readOffset = 0; 85 m_buffer.removeFirst(); 86 } 87 } 88 size()89 size_t size() const { return m_size; } 90 firstBlockData()91 const T* firstBlockData() const 92 { 93 if (!m_size) 94 return 0; 95 ASSERT(m_buffer.size() > 0); 96 return &m_buffer.first()->data()[m_readOffset]; 97 } 98 firstBlockSize()99 size_t firstBlockSize() const 100 { 101 if (!m_size) 102 return 0; 103 ASSERT(m_buffer.size() > 0); 104 return m_buffer.first()->size() - m_readOffset; 105 } 106 107 private: 108 size_t m_size; 109 size_t m_readOffset; 110 Deque<OwnPtr<Block> > m_buffer; 111 }; 112 113 } // namespace WTF 114 115 using WTF::StreamBuffer; 116 117 #endif // WTF_StreamBuffer_h 118