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OpenRCT2/src/openrct2/core/MemoryStream.h
2024-12-31 20:30:04 +01:00

121 lines
4.0 KiB
C++

/*****************************************************************************
* Copyright (c) 2014-2025 OpenRCT2 developers
*
* For a complete list of all authors, please refer to contributors.md
* Interested in contributing? Visit https://github.com/OpenRCT2/OpenRCT2
*
* OpenRCT2 is licensed under the GNU General Public License version 3.
*****************************************************************************/
#pragma once
#include "IStream.hpp"
#include <cstring>
#include <vector>
namespace OpenRCT2
{
namespace MEMORY_ACCESS
{
constexpr uint8_t READ = 1 << 0;
constexpr uint8_t WRITE = 1 << 1;
constexpr uint8_t OWNER = 1 << 2;
}; // namespace MEMORY_ACCESS
/**
* A stream for reading and writing to a buffer in memory. By default this buffer can grow.
*/
class MemoryStream final : public IStream
{
private:
uint8_t _access = MEMORY_ACCESS::READ | MEMORY_ACCESS::WRITE | MEMORY_ACCESS::OWNER;
size_t _dataCapacity = 0;
size_t _dataSize = 0;
void* _data = nullptr;
void* _position = nullptr;
public:
MemoryStream() = default;
MemoryStream(const MemoryStream& copy);
MemoryStream(MemoryStream&& mv) noexcept;
explicit MemoryStream(size_t capacity);
MemoryStream(void* data, size_t dataSize, uint8_t access = MEMORY_ACCESS::READ);
MemoryStream(const void* data, size_t dataSize);
MemoryStream(std::vector<uint8_t>&& v);
virtual ~MemoryStream();
MemoryStream& operator=(MemoryStream&& mv) noexcept;
const void* GetData() const override;
///////////////////////////////////////////////////////////////////////////
// ISteam methods
///////////////////////////////////////////////////////////////////////////
bool CanRead() const override;
bool CanWrite() const override;
uint64_t GetLength() const override;
uint64_t GetPosition() const override;
void SetPosition(uint64_t position) override;
void Seek(int64_t offset, int32_t origin) override;
void Read(void* buffer, uint64_t length) override;
void Read1(void* buffer) override;
void Read2(void* buffer) override;
void Read4(void* buffer) override;
void Read8(void* buffer) override;
void Read16(void* buffer) override;
template<size_t N>
void Read(void* buffer)
{
uint64_t position = GetPosition();
if (position + N > _dataSize)
{
throw IOException("Attempted to read past end of stream.");
}
std::memcpy(buffer, _position, N);
_position = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(_position) + N);
}
void Write(const void* buffer, uint64_t length) override;
void Write1(const void* buffer) override;
void Write2(const void* buffer) override;
void Write4(const void* buffer) override;
void Write8(const void* buffer) override;
void Write16(const void* buffer) override;
template<size_t N>
void Write(const void* buffer)
{
uint64_t position = GetPosition();
uint64_t nextPosition = position + N;
if (nextPosition > _dataCapacity)
{
if (_access & MEMORY_ACCESS::OWNER)
{
EnsureCapacity(static_cast<size_t>(nextPosition));
}
else
{
throw IOException("Attempted to write past end of stream.");
}
}
std::memcpy(_position, buffer, N);
_position = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(_position) + N);
_dataSize = std::max<size_t>(_dataSize, static_cast<size_t>(nextPosition));
}
uint64_t TryRead(void* buffer, uint64_t length) override;
void Clear();
private:
void EnsureCapacity(size_t capacity);
};
} // namespace OpenRCT2