102 lines
1.8 KiB
C++
102 lines
1.8 KiB
C++
/* SPDX-License-Identifier: BSL-1.0 OR BSD-3-Clause */
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#ifndef MPT_IO_READ_FILEDATA_MEMORY_HPP
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#define MPT_IO_READ_FILEDATA_MEMORY_HPP
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#include "mpt/base/memory.hpp"
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#include "mpt/base/namespace.hpp"
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#include "mpt/io_read/filedata.hpp"
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#include <algorithm>
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#include <cstddef>
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namespace mpt {
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inline namespace MPT_INLINE_NS {
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namespace IO {
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class FileDataMemory
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: public IFileData {
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private:
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const std::byte * streamData; // Pointer to memory-mapped file
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pos_type streamLength; // Size of memory-mapped file in bytes
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public:
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FileDataMemory()
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: streamData(nullptr)
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, streamLength(0) { }
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FileDataMemory(mpt::const_byte_span data)
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: streamData(data.data())
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, streamLength(data.size()) { }
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public:
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bool IsValid() const override {
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return streamData != nullptr;
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}
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bool HasFastGetLength() const override {
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return true;
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}
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bool HasPinnedView() const override {
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return true;
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}
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const std::byte * GetRawData() const override {
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return streamData;
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}
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pos_type GetLength() const override {
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return streamLength;
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}
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mpt::byte_span Read(pos_type pos, mpt::byte_span dst) const override {
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if (pos >= streamLength) {
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return dst.first(0);
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}
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pos_type avail = std::min(streamLength - pos, dst.size());
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std::copy(streamData + pos, streamData + pos + avail, dst.data());
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return dst.first(avail);
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}
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bool CanRead(pos_type pos, pos_type length) const override {
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if ((pos == streamLength) && (length == 0)) {
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return true;
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}
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if (pos >= streamLength) {
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return false;
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}
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return (length <= streamLength - pos);
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}
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pos_type GetReadableLength(pos_type pos, pos_type length) const override {
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if (pos >= streamLength) {
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return 0;
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}
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return std::min(length, streamLength - pos);
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}
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};
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} // namespace IO
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} // namespace MPT_INLINE_NS
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} // namespace mpt
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#endif // MPT_IO_READ_FILEDATA_MEMORY_HPP
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