114 lines
2.0 KiB
C++
114 lines
2.0 KiB
C++
// SPDX-License-Identifier: BSD-2-Clause
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// author: Max Kellermann <max.kellermann@gmail.com>
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#include "FileReader.hxx"
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#include "lib/fmt/PathFormatter.hxx"
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#include "fs/AllocatedPath.hxx"
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#include "fs/FileInfo.hxx"
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#include "lib/fmt/SystemError.hxx"
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#include "io/Open.hxx"
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#include <cassert>
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#ifdef _WIN32
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FileReader::FileReader(Path path)
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:handle(CreateFile(path.c_str(), GENERIC_READ, FILE_SHARE_READ,
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nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
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nullptr))
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{
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if (handle == INVALID_HANDLE_VALUE)
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throw FmtLastError("Failed to open {}", path);
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}
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FileInfo
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FileReader::GetFileInfo() const
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{
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assert(IsDefined());
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return FileInfo{handle};
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}
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std::size_t
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FileReader::Read(std::span<std::byte> dest)
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{
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assert(IsDefined());
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DWORD nbytes;
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if (!ReadFile(handle, dest.data(), dest.size(), &nbytes, nullptr))
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throw MakeLastError("Failed to read from file");
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return nbytes;
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}
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void
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FileReader::Seek(off_t offset)
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{
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assert(IsDefined());
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auto result = SetFilePointer(handle, offset, nullptr, FILE_BEGIN);
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if (result == INVALID_SET_FILE_POINTER)
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throw MakeLastError("Failed to seek");
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}
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void
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FileReader::Skip(off_t offset)
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{
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assert(IsDefined());
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auto result = SetFilePointer(handle, offset, nullptr, FILE_CURRENT);
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if (result == INVALID_SET_FILE_POINTER)
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throw MakeLastError("Failed to seek");
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}
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#else
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FileReader::FileReader(Path path)
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:fd(OpenReadOnly(path.c_str()))
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{
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}
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FileInfo
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FileReader::GetFileInfo() const
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{
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assert(IsDefined());
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return FileInfo{fd};
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}
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std::size_t
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FileReader::Read(std::span<std::byte> dest)
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{
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assert(IsDefined());
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ssize_t nbytes = fd.Read(dest);
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if (nbytes < 0)
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throw MakeErrno("Failed to read from file");
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return nbytes;
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}
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void
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FileReader::Seek(off_t offset)
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{
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assert(IsDefined());
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auto result = fd.Seek(offset);
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const bool success = result >= 0;
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if (!success)
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throw MakeErrno("Failed to seek");
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}
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void
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FileReader::Skip(off_t offset)
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{
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assert(IsDefined());
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auto result = fd.Skip(offset);
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const bool success = result >= 0;
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if (!success)
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throw MakeErrno("Failed to seek");
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}
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#endif
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