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

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• Hash : b3f26b9e
  Author :
  Date : 2017-07-19T15:07:41
  

  Add a zero-filled scratch buffer to Context.
  
  We need this in a few places for handling resource init.
  Centralize this in the context so we don't have to recreate
  and re-fill a large zero buffer.
  
  BUG=angleproject:2107
  
  Change-Id: Icf9ce417e7ee3498f03e47741dfff89e81b49519
  Reviewed-on: https://chromium-review.googlesource.com/576057
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  Commit-Queue: Jamie Madill <jmadill@chromium.org>
  

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• src/common/MemoryBuffer.h

• //
  // Copyright (c) 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.
  //
  
  #ifndef COMMON_MEMORYBUFFER_H_
  #define COMMON_MEMORYBUFFER_H_
  
  #include "common/Optional.h"
  #include "common/angleutils.h"
  
  #include <stdint.h>
  #include <cstddef>
  
  namespace angle
  {
  
  class MemoryBuffer final : NonCopyable
  {
    public:
      MemoryBuffer();
      ~MemoryBuffer();
  
      MemoryBuffer(MemoryBuffer &&other);
      MemoryBuffer &operator=(MemoryBuffer &&other);
  
      bool resize(size_t size);
      size_t size() const;
      bool empty() const { return mSize == 0; }
  
      const uint8_t *data() const;
      uint8_t *data();
  
      void fill(uint8_t datum);
  
    private:
      size_t mSize;
      uint8_t *mData;
  };
  
  class ScratchBuffer final : NonCopyable
  {
    public:
      // If we request a scratch buffer requesting a smaller size this many times, release and
      // recreate the scratch buffer. This ensures we don't have a degenerate case where we are stuck
      // hogging memory.
      ScratchBuffer(uint32_t lifetime);
      ~ScratchBuffer();
  
      // Returns true with a memory buffer of the requested size, or false on failure.
      bool get(size_t requestedSize, MemoryBuffer **memoryBufferOut);
  
      // Same as get, but ensures new values are initialized to a fixed constant.
      bool getInitialized(size_t requestedSize, MemoryBuffer **memoryBufferOut, uint8_t initValue);
  
      // Ticks the release counter for the scratch buffer. Also done implicitly in get().
      void tick();
  
      void clear();
  
    private:
      bool getImpl(size_t requestedSize, MemoryBuffer **memoryBufferOut, Optional<uint8_t> initValue);
  
      const uint32_t mLifetime;
      uint32_t mResetCounter;
      MemoryBuffer mScratchMemory;
  };
  
  }  // namespace angle
  
  #endif  // COMMON_MEMORYBUFFER_H_
  

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