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// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license_dolphin.txt file included.

#pragma once

#include <cstddef>
#include <vector>

#include "Assert.h"
#include "../types.h"

namespace Common
{
// Everything that needs to generate code should inherit from this.
// You get memory management for free, plus, you can use all emitter functions without
// having to prefix them with gen-> or something similar.
// Example implementation:
// class JIT : public CodeBlock<ARMXEmitter> {}
template <class T>
class CodeBlock : public T
{
private:
  // A privately used function to set the executable RAM space to something invalid.
  // For debugging usefulness it should be used to set the RAM to a host specific breakpoint
  // instruction
  virtual void PoisonMemory() = 0;

protected:
  u8* region = nullptr;
  // Size of region we can use.
  size_t region_size = 0;
  // Original size of the region we allocated.
  size_t total_region_size = 0;

  bool m_is_child = false;
  std::vector<CodeBlock*> m_children;

public:
  CodeBlock() = default;
  virtual ~CodeBlock()
  {
  }
  CodeBlock(const CodeBlock&) = delete;
  CodeBlock& operator=(const CodeBlock&) = delete;
  CodeBlock(CodeBlock&&) = delete;
  CodeBlock& operator=(CodeBlock&&) = delete;

  // Always clear code space with breakpoints, so that if someone accidentally executes
  // uninitialized, it just breaks into the debugger.
  void ClearCodeSpace()
  {
    PoisonMemory();
    ResetCodePtr();
  }

  bool IsInSpace(const u8* ptr) const { return ptr >= region && ptr < (region + region_size); }

  void ResetCodePtr() { T::SetCodePtr(region); }
  size_t GetSpaceLeft() const
  {
    ASSERT(static_cast<size_t>(T::GetCodePtr() - region) < region_size);
    return region_size - (T::GetCodePtr() - region);
  }

  bool IsAlmostFull() const
  {
    // This should be bigger than the biggest block ever.
    return GetSpaceLeft() < 0x10000;
  }

  bool HasChildren() const { return region_size != total_region_size; }
  u8* AllocChildCodeSpace(size_t child_size)
  {
    ASSERT_MSG(DYNA_REC, child_size < GetSpaceLeft(), "Insufficient space for child allocation.");
    u8* child_region = region + region_size - child_size;
    region_size -= child_size;
    return child_region;
  }
  void AddChildCodeSpace(CodeBlock* child, size_t child_size)
  {
    u8* child_region = AllocChildCodeSpace(child_size);
    child->m_is_child = true;
    child->region = child_region;
    child->region_size = child_size;
    child->total_region_size = child_size;
    child->ResetCodePtr();
    m_children.emplace_back(child);
  }
};
}  // namespace Common