141 lines
5.1 KiB
C++
141 lines
5.1 KiB
C++
////////////////////////////////////////////////////////////
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//
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// SFML - Simple and Fast Multimedia Library
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// Copyright (C) 2007-2025 Laurent Gomila (laurent@sfml-dev.org)
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//
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// This software is provided 'as-is', without any express or implied warranty.
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// In no event will the authors be held liable for any damages arising from the use of this software.
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//
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// Permission is granted to anyone to use this software for any purpose,
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// including commercial applications, and to alter it and redistribute it freely,
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// subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented;
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// you must not claim that you wrote the original software.
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// If you use this software in a product, an acknowledgment
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// in the product documentation would be appreciated but is not required.
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//
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// 2. Altered source versions must be plainly marked as such,
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// and must not be misrepresented as being the original software.
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//
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// 3. This notice may not be removed or altered from any source distribution.
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//
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////////////////////////////////////////////////////////////
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#pragma once
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////////////////////////////////////////////////////////////
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// Headers
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////////////////////////////////////////////////////////////
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#include "../../SFML/Config.hpp"
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#include "../../SFML/System/Export.hpp"
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#include "../../SFML/System/InputStream.hpp"
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#include <cstddef>
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#include <cstdint>
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#include "optional.hpp"
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namespace sf
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{
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////////////////////////////////////////////////////////////
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/// \brief Implementation of input stream based on a memory chunk
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///
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////////////////////////////////////////////////////////////
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class SFML_SYSTEM_API MemoryInputStream : public InputStream
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{
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public:
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////////////////////////////////////////////////////////////
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/// \brief Construct the stream from its data
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///
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/// \param data Pointer to the data in memory
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/// \param sizeInBytes Size of the data, in bytes
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///
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////////////////////////////////////////////////////////////
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MemoryInputStream(const void* data, std::size_t sizeInBytes);
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////////////////////////////////////////////////////////////
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/// \brief Read data from the stream
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///
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/// After reading, the stream's reading position must be
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/// advanced by the amount of bytes read.
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///
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/// \param data Buffer where to copy the read data
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/// \param size Desired number of bytes to read
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///
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/// \return The number of bytes actually read, or `nonstd::nullopt` on error
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///
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////////////////////////////////////////////////////////////
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[[nodiscard]] nonstd::optional<std::size_t> read(void* data, std::size_t size) override;
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////////////////////////////////////////////////////////////
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/// \brief Change the current reading position
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///
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/// \param position The position to seek to, from the beginning
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///
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/// \return The position actually sought to, or `nonstd::nullopt` on error
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///
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////////////////////////////////////////////////////////////
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[[nodiscard]] nonstd::optional<std::size_t> seek(std::size_t position) override;
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////////////////////////////////////////////////////////////
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/// \brief Get the current reading position in the stream
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///
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/// \return The current position, or `nonstd::nullopt` on error.
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///
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////////////////////////////////////////////////////////////
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[[nodiscard]] nonstd::optional<std::size_t> tell() override;
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////////////////////////////////////////////////////////////
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/// \brief Return the size of the stream
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///
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/// \return The total number of bytes available in the stream, or `nonstd::nullopt` on error
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///
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////////////////////////////////////////////////////////////
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nonstd::optional<std::size_t> getSize() override;
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private:
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////////////////////////////////////////////////////////////
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// Member data
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////////////////////////////////////////////////////////////
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const unsigned char* m_data{}; //!< Pointer to the data in memory
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std::size_t m_size{}; //!< Total size of the data
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std::size_t m_offset{}; //!< Current reading position
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};
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} // namespace sf
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////////////////////////////////////////////////////////////
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/// \class sf::MemoryInputStream
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/// \ingroup system
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///
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/// This class is a specialization of `InputStream` that
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/// reads from data in memory.
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///
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/// It wraps a memory chunk in the common `InputStream` interface
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/// and therefore allows to use generic classes or functions
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/// that accept such a stream, with content already loaded in memory.
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///
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/// In addition to the virtual functions inherited from
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/// `InputStream`, `MemoryInputStream` adds a function to
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/// specify the pointer and size of the data in memory.
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///
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/// SFML resource classes can usually be loaded directly from
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/// memory, so this class shouldn't be useful to you unless
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/// you create your own algorithms that operate on an InputStream.
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///
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/// Usage example:
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/// \code
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/// void process(InputStream& stream);
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///
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/// MemoryInputStream stream(thePtr, theSize);
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/// process(stream);
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/// \endcode
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///
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/// \see `InputStream`, `FileInputStream`
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///
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////////////////////////////////////////////////////////////
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