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| 1 /* | 1 /* |
| 2 * Copyright (C) 2013 Google Inc. All rights reserved. | 2 * Copyright (C) 2013 Google Inc. All rights reserved. |
| 3 * | 3 * |
| 4 * Redistribution and use in source and binary forms, with or without | 4 * Redistribution and use in source and binary forms, with or without |
| 5 * modification, are permitted provided that the following conditions are | 5 * modification, are permitted provided that the following conditions are |
| 6 * met: | 6 * met: |
| 7 * | 7 * |
| 8 * * Redistributions of source code must retain the above copyright | 8 * * Redistributions of source code must retain the above copyright |
| 9 * notice, this list of conditions and the following disclaimer. | 9 * notice, this list of conditions and the following disclaimer. |
| 10 * * Redistributions in binary form must reproduce the above | 10 * * Redistributions in binary form must reproduce the above |
| (...skipping 21 matching lines...) Expand all Loading... |
| 32 #include "wtf/ArrayBufferBuilder.h" | 32 #include "wtf/ArrayBufferBuilder.h" |
| 33 | 33 |
| 34 #include "wtf/Assertions.h" | 34 #include "wtf/Assertions.h" |
| 35 #include <limits> | 35 #include <limits> |
| 36 | 36 |
| 37 namespace WTF { | 37 namespace WTF { |
| 38 | 38 |
| 39 static const int defaultBufferCapacity = 32768; | 39 static const int defaultBufferCapacity = 32768; |
| 40 | 40 |
| 41 ArrayBufferBuilder::ArrayBufferBuilder() | 41 ArrayBufferBuilder::ArrayBufferBuilder() |
| 42 : m_bytesUsed(0) | 42 : m_bytesUsed(0), m_variableCapacity(true) { |
| 43 , m_variableCapacity(true) | 43 m_buffer = ArrayBuffer::create(defaultBufferCapacity, 1); |
| 44 { | |
| 45 m_buffer = ArrayBuffer::create(defaultBufferCapacity, 1); | |
| 46 } | 44 } |
| 47 | 45 |
| 48 bool ArrayBufferBuilder::expandCapacity(unsigned sizeToIncrease) | 46 bool ArrayBufferBuilder::expandCapacity(unsigned sizeToIncrease) { |
| 49 { | 47 unsigned currentBufferSize = m_buffer->byteLength(); |
| 50 unsigned currentBufferSize = m_buffer->byteLength(); | |
| 51 | 48 |
| 52 // If the size of the buffer exceeds max of unsigned, it can't be grown any | 49 // If the size of the buffer exceeds max of unsigned, it can't be grown any |
| 53 // more. | 50 // more. |
| 54 if (sizeToIncrease > std::numeric_limits<unsigned>::max() - m_bytesUsed) | 51 if (sizeToIncrease > std::numeric_limits<unsigned>::max() - m_bytesUsed) |
| 55 return false; | 52 return false; |
| 56 | 53 |
| 57 unsigned newBufferSize = m_bytesUsed + sizeToIncrease; | 54 unsigned newBufferSize = m_bytesUsed + sizeToIncrease; |
| 58 | 55 |
| 59 // Grow exponentially if possible. | 56 // Grow exponentially if possible. |
| 60 unsigned exponentialGrowthNewBufferSize = std::numeric_limits<unsigned>::max
(); | 57 unsigned exponentialGrowthNewBufferSize = std::numeric_limits<unsigned>::max()
; |
| 61 if (currentBufferSize <= std::numeric_limits<unsigned>::max() / 2) | 58 if (currentBufferSize <= std::numeric_limits<unsigned>::max() / 2) |
| 62 exponentialGrowthNewBufferSize = currentBufferSize * 2; | 59 exponentialGrowthNewBufferSize = currentBufferSize * 2; |
| 63 if (exponentialGrowthNewBufferSize > newBufferSize) | 60 if (exponentialGrowthNewBufferSize > newBufferSize) |
| 64 newBufferSize = exponentialGrowthNewBufferSize; | 61 newBufferSize = exponentialGrowthNewBufferSize; |
| 65 | 62 |
| 66 // Copy existing data in current buffer to new buffer. | 63 // Copy existing data in current buffer to new buffer. |
| 67 RefPtr<ArrayBuffer> newBuffer = ArrayBuffer::create(newBufferSize, 1); | 64 RefPtr<ArrayBuffer> newBuffer = ArrayBuffer::create(newBufferSize, 1); |
| 68 if (!newBuffer) | 65 if (!newBuffer) |
| 69 return false; | 66 return false; |
| 70 | 67 |
| 71 memcpy(newBuffer->data(), m_buffer->data(), m_bytesUsed); | 68 memcpy(newBuffer->data(), m_buffer->data(), m_bytesUsed); |
| 72 m_buffer = newBuffer; | 69 m_buffer = newBuffer; |
| 73 return true; | 70 return true; |
| 74 } | 71 } |
| 75 | 72 |
| 76 unsigned ArrayBufferBuilder::append(const char* data, unsigned length) | 73 unsigned ArrayBufferBuilder::append(const char* data, unsigned length) { |
| 77 { | 74 ASSERT(length > 0); |
| 78 ASSERT(length > 0); | |
| 79 | 75 |
| 80 unsigned currentBufferSize = m_buffer->byteLength(); | 76 unsigned currentBufferSize = m_buffer->byteLength(); |
| 81 | 77 |
| 82 ASSERT(m_bytesUsed <= currentBufferSize); | 78 ASSERT(m_bytesUsed <= currentBufferSize); |
| 83 | 79 |
| 84 unsigned remainingBufferSpace = currentBufferSize - m_bytesUsed; | 80 unsigned remainingBufferSpace = currentBufferSize - m_bytesUsed; |
| 85 | 81 |
| 86 unsigned bytesToSave = length; | 82 unsigned bytesToSave = length; |
| 87 | 83 |
| 88 if (length > remainingBufferSpace) { | 84 if (length > remainingBufferSpace) { |
| 89 if (m_variableCapacity) { | 85 if (m_variableCapacity) { |
| 90 if (!expandCapacity(length)) | 86 if (!expandCapacity(length)) |
| 91 return 0; | 87 return 0; |
| 92 } else { | 88 } else { |
| 93 bytesToSave = remainingBufferSpace; | 89 bytesToSave = remainingBufferSpace; |
| 94 } | |
| 95 } | 90 } |
| 91 } |
| 96 | 92 |
| 97 memcpy(static_cast<char*>(m_buffer->data()) + m_bytesUsed, data, bytesToSave
); | 93 memcpy(static_cast<char*>(m_buffer->data()) + m_bytesUsed, data, bytesToSave); |
| 98 m_bytesUsed += bytesToSave; | 94 m_bytesUsed += bytesToSave; |
| 99 | 95 |
| 100 return bytesToSave; | 96 return bytesToSave; |
| 101 } | 97 } |
| 102 | 98 |
| 103 PassRefPtr<ArrayBuffer> ArrayBufferBuilder::toArrayBuffer() | 99 PassRefPtr<ArrayBuffer> ArrayBufferBuilder::toArrayBuffer() { |
| 104 { | 100 // Fully used. Return m_buffer as-is. |
| 105 // Fully used. Return m_buffer as-is. | 101 if (m_buffer->byteLength() == m_bytesUsed) |
| 106 if (m_buffer->byteLength() == m_bytesUsed) | 102 return m_buffer; |
| 107 return m_buffer; | |
| 108 | 103 |
| 109 return m_buffer->slice(0, m_bytesUsed); | 104 return m_buffer->slice(0, m_bytesUsed); |
| 110 } | 105 } |
| 111 | 106 |
| 112 String ArrayBufferBuilder::toString() | 107 String ArrayBufferBuilder::toString() { |
| 113 { | 108 return String(static_cast<const char*>(m_buffer->data()), m_bytesUsed); |
| 114 return String(static_cast<const char*>(m_buffer->data()), m_bytesUsed); | |
| 115 } | 109 } |
| 116 | 110 |
| 117 void ArrayBufferBuilder::shrinkToFit() | 111 void ArrayBufferBuilder::shrinkToFit() { |
| 118 { | 112 ASSERT(m_bytesUsed <= m_buffer->byteLength()); |
| 119 ASSERT(m_bytesUsed <= m_buffer->byteLength()); | |
| 120 | 113 |
| 121 if (m_buffer->byteLength() > m_bytesUsed) | 114 if (m_buffer->byteLength() > m_bytesUsed) |
| 122 m_buffer = m_buffer->slice(0, m_bytesUsed); | 115 m_buffer = m_buffer->slice(0, m_bytesUsed); |
| 123 } | 116 } |
| 124 | 117 |
| 125 } // namespace WTF | 118 } // namespace WTF |
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