buffer.hh

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/*
 
MIT License
 
Copyright (c) 2025 PCSX-Redux authors
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
 
*/
 
#include <stdint.h>
 
#include "common/util/bitfield.hh"
 
namespace Utilities {
 
template <typename T, class Allocator>
class Buffer {
    typedef BitSpan<uint32_t, 24> SizeField;
    typedef BitSpan<bool> IsExternalField;
    typedef BitField<SizeField, IsExternalField> Size;
 
  public:
    Buffer() { m_size.clear(); }
    Buffer(size_t size) {
        m_size.clear();
        resize(size);
    }
    Buffer(T* data, size_t size) {
        m_data = data;
        m_size.set<SizeField>(size);
        m_size.set<IsExternalField>(true);
    }
    Buffer(const Buffer& other) {
        uint32_t size = other.m_size.get<SizeField>();
        m_size.set<SizeField>(size);
        m_size.set<IsExternalField>(false);
        m_data = Allocator::template allocate<T>(size);
        Allocator::copy(m_data, other.m_data, size);
    }
    Buffer(Buffer&& other) noexcept : m_data(other.m_data), m_size(other.m_size) {
        other.m_data = nullptr;
        other.m_size.clear();
    }
    ~Buffer() {
        if (!m_size.get<IsExternalField>()) {
            Allocator::deallocate(m_data);
        }
    }
 
    Buffer& operator=(const Buffer& other) {
        if (this != &other) {
            uint32_t size = other.m_size.get<SizeField>();
            if (m_size.get<IsExternalField>()) {
                m_data = Allocator::template allocate<T>(size);
            } else {
                m_data = Allocator::template reallocate<T>(m_data, size);
            }
            Allocator::copy(m_data, other.m_data, size);
            m_size.set<SizeField>(size);
            m_size.set<IsExternalField>(false);
        }
        return *this;
    }
    Buffer& operator=(Buffer&& other) noexcept {
        if (this != &other) {
            if (!m_size.get<IsExternalField>()) {
                Allocator::deallocate(m_data);
            }
            m_data = other.m_data;
            m_size = other.m_size;
            other.m_data = nullptr;
            other.m_size.clear();
        }
        return *this;
    }
 
    void clear() {
        if (!m_size.get<IsExternalField>()) {
            Allocator::deallocate(m_data);
        }
        m_data = nullptr;
        m_size.clear();
    }
 
    void resize(size_t size) {
        if (!m_size.get<IsExternalField>()) {
            m_data = Allocator::template reallocate<T>(m_data, size);
        }
        m_size.set<SizeField>(size);
    }
 
    T* data() { return m_data; }
    const T* data() const { return m_data; }
    size_t size() const { return m_size.get<SizeField>(); }
    T& operator[](size_t index) { return m_data[index]; }
    const T& operator[](size_t index) const { return m_data[index]; }
    T* begin() { return m_data; }
    T* end() { return m_data + m_size.get<SizeField>(); }
    const T* begin() const { return m_data; }
    const T* end() const { return m_data + m_size.get<SizeField>(); }
    bool empty() const { return size() == 0; }
 
  private:
    T* m_data = nullptr;
    Size m_size;
};
 
}  // namespace Utilities