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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 "wtf/typed_arrays/ArrayBufferBuilder.h" | |
| 32 | |
| 33 #include "wtf/Assertions.h" | |
| 34 #include <limits> | |
| 35 | |
| 36 namespace WTF { | |
| 37 | |
| 38 static const int defaultBufferCapacity = 32768; | |
| 39 | |
| 40 ArrayBufferBuilder::ArrayBufferBuilder() | |
| 41 : m_bytesUsed(0), m_variableCapacity(true) { | |
| 42 m_buffer = ArrayBuffer::create(defaultBufferCapacity, 1); | |
| 43 } | |
| 44 | |
| 45 bool ArrayBufferBuilder::expandCapacity(unsigned sizeToIncrease) { | |
| 46 unsigned currentBufferSize = m_buffer->byteLength(); | |
| 47 | |
| 48 // If the size of the buffer exceeds max of unsigned, it can't be grown any | |
| 49 // more. | |
| 50 if (sizeToIncrease > std::numeric_limits<unsigned>::max() - m_bytesUsed) | |
| 51 return false; | |
| 52 | |
| 53 unsigned newBufferSize = m_bytesUsed + sizeToIncrease; | |
| 54 | |
| 55 // Grow exponentially if possible. | |
| 56 unsigned exponentialGrowthNewBufferSize = | |
| 57 std::numeric_limits<unsigned>::max(); | |
| 58 if (currentBufferSize <= std::numeric_limits<unsigned>::max() / 2) | |
| 59 exponentialGrowthNewBufferSize = currentBufferSize * 2; | |
| 60 if (exponentialGrowthNewBufferSize > newBufferSize) | |
| 61 newBufferSize = exponentialGrowthNewBufferSize; | |
| 62 | |
| 63 // Copy existing data in current buffer to new buffer. | |
| 64 RefPtr<ArrayBuffer> newBuffer = ArrayBuffer::create(newBufferSize, 1); | |
| 65 if (!newBuffer) | |
| 66 return false; | |
| 67 | |
| 68 memcpy(newBuffer->data(), m_buffer->data(), m_bytesUsed); | |
| 69 m_buffer = newBuffer; | |
| 70 return true; | |
| 71 } | |
| 72 | |
| 73 unsigned ArrayBufferBuilder::append(const char* data, unsigned length) { | |
| 74 DCHECK_GT(length, 0u); | |
| 75 | |
| 76 unsigned currentBufferSize = m_buffer->byteLength(); | |
| 77 | |
| 78 DCHECK_LE(m_bytesUsed, currentBufferSize); | |
| 79 | |
| 80 unsigned remainingBufferSpace = currentBufferSize - m_bytesUsed; | |
| 81 | |
| 82 unsigned bytesToSave = length; | |
| 83 | |
| 84 if (length > remainingBufferSpace) { | |
| 85 if (m_variableCapacity) { | |
| 86 if (!expandCapacity(length)) | |
| 87 return 0; | |
| 88 } else { | |
| 89 bytesToSave = remainingBufferSpace; | |
| 90 } | |
| 91 } | |
| 92 | |
| 93 memcpy(static_cast<char*>(m_buffer->data()) + m_bytesUsed, data, bytesToSave); | |
| 94 m_bytesUsed += bytesToSave; | |
| 95 | |
| 96 return bytesToSave; | |
| 97 } | |
| 98 | |
| 99 PassRefPtr<ArrayBuffer> ArrayBufferBuilder::toArrayBuffer() { | |
| 100 // Fully used. Return m_buffer as-is. | |
| 101 if (m_buffer->byteLength() == m_bytesUsed) | |
| 102 return m_buffer; | |
| 103 | |
| 104 return m_buffer->slice(0, m_bytesUsed); | |
| 105 } | |
| 106 | |
| 107 String ArrayBufferBuilder::toString() { | |
| 108 return String(static_cast<const char*>(m_buffer->data()), m_bytesUsed); | |
| 109 } | |
| 110 | |
| 111 void ArrayBufferBuilder::shrinkToFit() { | |
| 112 DCHECK_LE(m_bytesUsed, m_buffer->byteLength()); | |
| 113 | |
| 114 if (m_buffer->byteLength() > m_bytesUsed) | |
| 115 m_buffer = m_buffer->slice(0, m_bytesUsed); | |
| 116 } | |
| 117 | |
| 118 } // namespace WTF | |
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Chromium Code Reviews
Issue 2768063003:
Move files in wtf/ to platform/wtf/ (Part 11). (Closed)
