Refactor Compression and Streams, and Add IStream Direct Interface

src/openrct2/core/StreamBuffer.cpp

@@ -0,0 +1,161 @@
+/*****************************************************************************
+ * 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.
+ *****************************************************************************/
+
+#include "StreamBuffer.hpp"
+
+#include "Guard.hpp"
+#include "Memory.hpp"
+
+namespace OpenRCT2
+{
+    StreamReadBuffer::StreamReadBuffer(IStream& stream, uint64_t length, size_t bufferLength)
+    {
+        OpenRCT2::Guard::Assert(bufferLength > 0);
+
+        _remaining = length;
+        if (length <= std::numeric_limits<size_t>::max())
+            _buffer = static_cast<const uint8_t*>(stream.ReadDirect(static_cast<size_t>(length)));
+
+        if (_buffer == nullptr)
+        {
+            if (length > stream.GetLength() - stream.GetPosition())
+                throw IOException("Buffer Will Read Past the End of the Stream");
+
+            _bufferLength = bufferLength;
+            _buffer = OpenRCT2::Memory::Allocate<const uint8_t>(_bufferLength);
+        }
+    }
+
+    StreamReadBuffer::~StreamReadBuffer()
+    {
+        if (_bufferLength > 0)
+            OpenRCT2::Memory::Free(_buffer);
+
+        _buffer = nullptr;
+        _bufferLength = 0;
+        _remaining = 0;
+    }
+
+    StreamReadBuffer::StreamReadBuffer(StreamReadBuffer&& other) noexcept
+    {
+        _buffer = other._buffer;
+        _bufferLength = other._bufferLength;
+        _remaining = other._remaining;
+
+        other._buffer = nullptr;
+        other._bufferLength = 0;
+        other._remaining = 0;
+    }
+
+    StreamReadBuffer& StreamReadBuffer::operator=(StreamReadBuffer&& other) noexcept
+    {
+        if (&other != this)
+        {
+            _buffer = other._buffer;
+            _bufferLength = other._bufferLength;
+            _remaining = other._remaining;
+
+            other._buffer = nullptr;
+            other._bufferLength = 0;
+            other._remaining = 0;
+        }
+        return *this;
+    }
+
+    std::pair<const void*, size_t> StreamReadBuffer::ReadBlock(IStream& stream, size_t maxLength)
+    {
+        const uint8_t* ptr = _buffer;
+        size_t len = static_cast<size_t>(std::min<uint64_t>(_remaining, maxLength));
+        if (_bufferLength == 0)
+        {
+            _buffer += len;
+        }
+        else
+        {
+            len = static_cast<size_t>(std::min(len, _bufferLength));
+            stream.Read(const_cast<uint8_t*>(ptr), len);
+        }
+        _remaining -= len;
+        return { ptr, len };
+    }
+
+    StreamWriteBuffer::StreamWriteBuffer(IStream& stream, uint64_t length, size_t bufferLength)
+    {
+        OpenRCT2::Guard::Assert(bufferLength > 0);
+
+        _remaining = length;
+        if (length <= std::numeric_limits<size_t>::max())
+            _buffer = static_cast<uint8_t*>(stream.WriteDirectStart(static_cast<size_t>(length)));
+
+        if (_buffer == nullptr)
+        {
+            _bufferLength = bufferLength;
+            _buffer = OpenRCT2::Memory::Allocate<uint8_t>(_bufferLength);
+        }
+    }
+
+    StreamWriteBuffer::~StreamWriteBuffer()
+    {
+        if (_bufferLength > 0)
+            OpenRCT2::Memory::Free(_buffer);
+
+        _buffer = nullptr;
+        _bufferLength = 0;
+        _remaining = 0;
+    }
+
+    StreamWriteBuffer::StreamWriteBuffer(StreamWriteBuffer&& other) noexcept
+    {
+        _buffer = other._buffer;
+        _bufferLength = other._bufferLength;
+        _remaining = other._remaining;
+
+        other._buffer = nullptr;
+        other._bufferLength = 0;
+        other._remaining = 0;
+    }
+
+    StreamWriteBuffer& StreamWriteBuffer::operator=(StreamWriteBuffer&& other) noexcept
+    {
+        if (&other != this)
+        {
+            _buffer = other._buffer;
+            _bufferLength = other._bufferLength;
+            _remaining = other._remaining;
+
+            other._buffer = nullptr;
+            other._bufferLength = 0;
+            other._remaining = 0;
+        }
+        return *this;
+    }
+
+    std::pair<void*, size_t> StreamWriteBuffer::WriteBlockStart(size_t maxLength)
+    {
+        size_t len = static_cast<size_t>(std::min<uint64_t>(_remaining, maxLength));
+        if (_bufferLength > 0)
+            len = std::min(len, _bufferLength);
+
+        return { _buffer, len };
+    }
+
+    void StreamWriteBuffer::WriteBlockCommit(IStream& stream, size_t length)
+    {
+        if (_bufferLength == 0)
+        {
+            stream.WriteDirectCommit(length);
+            _buffer += length;
+        }
+        else
+        {
+            stream.Write(_buffer, length);
+        }
+        _remaining -= length;
+    }
+} // namespace OpenRCT2