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#include "file.hpp"
#include <cassert>
#include <components/misc/windows.hpp>
#include <stdexcept>
#include <string>
#include <components/files/conversion.hpp>
namespace Platform::File
{
static auto getNativeHandle(Handle handle)
{
assert(handle != Handle::Invalid);
return reinterpret_cast<HANDLE>(static_cast<intptr_t>(handle));
}
static int getNativeSeekType(SeekType seek)
{
if (seek == SeekType::Begin)
return FILE_BEGIN;
if (seek == SeekType::Current)
return FILE_CURRENT;
if (seek == SeekType::End)
return FILE_END;
return -1;
}
Handle open(const std::filesystem::path& filename)
{
HANDLE handle = CreateFileW(filename.c_str(), GENERIC_READ, FILE_SHARE_READ, 0, OPEN_EXISTING, 0, 0);
if (handle == INVALID_HANDLE_VALUE)
{
throw std::runtime_error(std::string("Failed to open '") + Files::pathToUnicodeString(filename)
+ "' for reading: " + std::to_string(GetLastError()));
}
return static_cast<Handle>(reinterpret_cast<intptr_t>(handle));
}
void close(Handle handle)
{
auto nativeHandle = getNativeHandle(handle);
CloseHandle(nativeHandle);
}
void seek(Handle handle, size_t position, SeekType type /*= SeekType::Begin*/)
{
const auto nativeHandle = getNativeHandle(handle);
const auto nativeSeekType = getNativeSeekType(type);
LARGE_INTEGER li;
li.QuadPart = static_cast<LONGLONG>(position);
if (!SetFilePointerEx(nativeHandle, li, nullptr, nativeSeekType))
{
if (auto errCode = GetLastError(); errCode != ERROR_SUCCESS)
{
throw std::runtime_error(std::string("An fseek() call failed: ") + std::to_string(errCode));
}
}
}
size_t size(Handle handle)
{
auto nativeHandle = getNativeHandle(handle);
BY_HANDLE_FILE_INFORMATION info;
if (!GetFileInformationByHandle(nativeHandle, &info))
throw std::runtime_error("A query operation on a file failed.");
if (info.nFileSizeHigh != 0)
throw std::runtime_error("Files greater that 4GB are not supported.");
return info.nFileSizeLow;
}
size_t tell(Handle handle)
{
auto nativeHandle = getNativeHandle(handle);
DWORD value = SetFilePointer(nativeHandle, 0, nullptr, SEEK_CUR);
if (value == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR)
throw std::runtime_error("A query operation on a file failed.");
return value;
}
size_t read(Handle handle, void* data, size_t size)
{
auto nativeHandle = getNativeHandle(handle);
DWORD bytesRead{};
if (!ReadFile(nativeHandle, data, static_cast<DWORD>(size), &bytesRead, nullptr))
throw std::runtime_error(
std::string("A read operation on a file failed: ") + std::to_string(GetLastError()));
return bytesRead;
}
}
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