147 lines
3.2 KiB
C++
147 lines
3.2 KiB
C++
// Copyright (C) 2015 Jérôme Leclercq
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// This file is part of the "Nazara Engine - Core module"
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// For conditions of distribution and use, see copyright notice in Config.hpp
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#include <Nazara/Core/MemoryView.hpp>
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#include <algorithm>
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#include <cstring>
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#include <Nazara/Core/Debug.hpp>
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namespace Nz
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{
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/*!
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* \class Nz::MemoryView
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* \brief Core class that represents a view of the memory behaving like a stream
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*/
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/*!
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* \brief Constructs a MemoryView object with a raw memory and a size
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*
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* \param ptr Pointer to raw memory
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* \param size Size that can be read
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*
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* \remark If preallocated space of ptr is less than the size, the behaviour is undefined
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*/
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MemoryView::MemoryView(void* ptr, UInt64 size) :
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Stream(StreamOption_None, OpenMode_ReadWrite),
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m_ptr(reinterpret_cast<UInt8*>(ptr)),
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m_pos(0),
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m_size(size)
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{
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}
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/*!
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* \brief Constructs a MemoryView object with a raw memory and a size
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*
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* \param ptr Constant pointer to raw memory
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* \param size Size that can be read
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*
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* \remark If preallocated space of ptr is less than the size, the behaviour is undefined
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*/
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MemoryView::MemoryView(const void* ptr, UInt64 size) :
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Stream(StreamOption_None, OpenMode_ReadOnly),
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m_ptr(reinterpret_cast<UInt8*>(const_cast<void*>(ptr))), //< Okay, right, const_cast is bad, but this pointer is still read-only
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m_pos(0),
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m_size(size)
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{
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}
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/*!
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* \brief Checks whether the stream reached the end of the stream
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* \return true if cursor is at the end of the stream
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*/
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bool MemoryView::EndOfStream() const
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{
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return m_pos >= m_size;
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}
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/*!
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* \brief Gets the position of the cursor
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* \return Position of the cursor
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*/
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UInt64 MemoryView::GetCursorPos() const
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{
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return m_pos;
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}
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/*!
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* \brief Gets the size of the raw memory
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* \return Size of the memory
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*/
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UInt64 MemoryView::GetSize() const
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{
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return m_size;
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}
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/*!
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* \brief Sets the position of the cursor
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* \return true
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*
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* \param offset Offset according to the beginning of the stream
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*/
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bool MemoryView::SetCursorPos(UInt64 offset)
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{
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m_pos = std::min(offset, m_size);
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return true;
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}
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/*!
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* \brief Flushes the stream
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*/
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void MemoryView::FlushStream()
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{
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// Nothing to do
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}
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/*!
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* \brief Reads blocks
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* \return Number of blocks read
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*
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* \param buffer Preallocated buffer to contain information read
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* \param size Size of the read and thus of the buffer
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*/
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std::size_t MemoryView::ReadBlock(void* buffer, std::size_t size)
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{
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std::size_t readSize = std::min<std::size_t>(size, static_cast<std::size_t>(m_size - m_pos));
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if (buffer)
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std::memcpy(buffer, &m_ptr[m_pos], readSize);
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m_pos += readSize;
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return readSize;
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}
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/*!
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* \brief Writes blocks
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* \return Number of blocks written
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*
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* \param buffer Preallocated buffer containing information to write
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* \param size Size of the writting and thus of the buffer
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*
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* \remark Produces a NazaraAssert if buffer is nullptr
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*/
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std::size_t MemoryView::WriteBlock(const void* buffer, std::size_t size)
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{
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std::size_t endPos = static_cast<std::size_t>(m_pos + size);
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if (endPos > m_size)
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size = m_size - m_pos;
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NazaraAssert(buffer, "Invalid buffer");
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std::memcpy(&m_ptr[m_pos], buffer, size);
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m_pos += size;
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return size;
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}
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}
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