kc3-lang/angle/src/common/MemoryBuffer.cpp

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• Hash : 9aa6d3da
  Author :
  Date : 2024-04-26T11:34:10
  

  Add trim support to MemoryBuffer
  
  There are usecases where we need a MemoryBuffer to be trimmed to a
  smaller size. In such cases there is no need to perform a resize,
  which would trigger a reallocation. Instead just update
  MemoryBuffer's size.
  
  Bug: angleproject:4722
  Change-Id: I5b6cca121977903ffa7663591eaec62f6ffda97a
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5513269
  Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
  Commit-Queue: mohan maiya <m.maiya@samsung.com>
  

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• src/common/MemoryBuffer.cpp

• //
  // Copyright 2014 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  
  #include "common/MemoryBuffer.h"
  
  #include <algorithm>
  #include <cstdlib>
  
  #include "common/debug.h"
  
  namespace angle
  {
  
  // MemoryBuffer implementation.
  MemoryBuffer::~MemoryBuffer()
  {
      if (mData)
      {
          free(mData);
          mData = nullptr;
      }
  }
  
  bool MemoryBuffer::resize(size_t size)
  {
      if (size == 0)
      {
          if (mData)
          {
              free(mData);
              mData = nullptr;
          }
          mSize = 0;
          return true;
      }
  
      if (size == mSize)
      {
          return true;
      }
  
      // Only reallocate if the size has changed.
      uint8_t *newMemory = static_cast<uint8_t *>(malloc(sizeof(uint8_t) * size));
      if (newMemory == nullptr)
      {
          return false;
      }
  
      if (mData)
      {
          // Copy the intersection of the old data and the new data
          std::copy(mData, mData + std::min(mSize, size), newMemory);
          free(mData);
      }
  
      mData = newMemory;
      mSize = size;
  
      return true;
  }
  
  void MemoryBuffer::trim(size_t size)
  {
      ASSERT(size <= mSize);
      mSize = size;
  }
  
  void MemoryBuffer::fill(uint8_t datum)
  {
      if (!empty())
      {
          std::fill(mData, mData + mSize, datum);
      }
  }
  
  MemoryBuffer::MemoryBuffer(MemoryBuffer &&other) : MemoryBuffer()
  {
      *this = std::move(other);
  }
  
  MemoryBuffer &MemoryBuffer::operator=(MemoryBuffer &&other)
  {
      std::swap(mSize, other.mSize);
      std::swap(mData, other.mData);
      return *this;
  }
  
  namespace
  {
  static constexpr uint32_t kDefaultScratchBufferLifetime = 1000u;
  
  }  // anonymous namespace
  
  // ScratchBuffer implementation.
  ScratchBuffer::ScratchBuffer() : ScratchBuffer(kDefaultScratchBufferLifetime) {}
  
  ScratchBuffer::ScratchBuffer(uint32_t lifetime) : mLifetime(lifetime), mResetCounter(lifetime) {}
  
  ScratchBuffer::~ScratchBuffer() {}
  
  ScratchBuffer::ScratchBuffer(ScratchBuffer &&other)
  {
      *this = std::move(other);
  }
  
  ScratchBuffer &ScratchBuffer::operator=(ScratchBuffer &&other)
  {
      std::swap(mLifetime, other.mLifetime);
      std::swap(mResetCounter, other.mResetCounter);
      std::swap(mScratchMemory, other.mScratchMemory);
      return *this;
  }
  
  bool ScratchBuffer::get(size_t requestedSize, MemoryBuffer **memoryBufferOut)
  {
      return getImpl(requestedSize, memoryBufferOut, Optional<uint8_t>::Invalid());
  }
  
  bool ScratchBuffer::getInitialized(size_t requestedSize,
                                     MemoryBuffer **memoryBufferOut,
                                     uint8_t initValue)
  {
      return getImpl(requestedSize, memoryBufferOut, Optional<uint8_t>(initValue));
  }
  
  bool ScratchBuffer::getImpl(size_t requestedSize,
                              MemoryBuffer **memoryBufferOut,
                              Optional<uint8_t> initValue)
  {
      if (mScratchMemory.size() == requestedSize)
      {
          mResetCounter    = mLifetime;
          *memoryBufferOut = &mScratchMemory;
          return true;
      }
  
      if (mScratchMemory.size() > requestedSize)
      {
          tick();
      }
  
      if (mScratchMemory.size() < requestedSize)
      {
          if (!mScratchMemory.resize(requestedSize))
          {
              return false;
          }
          mResetCounter = mLifetime;
          if (initValue.valid())
          {
              mScratchMemory.fill(initValue.value());
          }
      }
  
      ASSERT(mScratchMemory.size() >= requestedSize);
  
      *memoryBufferOut = &mScratchMemory;
      return true;
  }
  
  void ScratchBuffer::tick()
  {
      if (mResetCounter > 0)
      {
          --mResetCounter;
          if (mResetCounter == 0)
          {
              clear();
          }
      }
  }
  
  void ScratchBuffer::clear()
  {
      mResetCounter = mLifetime;
      if (mScratchMemory.size() > 0)
      {
          mScratchMemory.clear();
      }
  }
  
  }  // namespace angle
  

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