internal static MemoryMappedDataReaderFactory CreateUnix(string filename, bool mapAsImage)
{
if (!canTryUnix)
{
return(null);
}
var creator = new MemoryMappedDataReaderFactory(GetFullPath(filename));
try {
Unix.Mmap(creator, mapAsImage);
if (mapAsImage) // Only check this if we know that mmap() works, i.e., if above call succeeds
{
creator.Dispose();
throw new ArgumentException("mapAsImage == true is not supported on this OS");
}
return(creator);
}
catch (MemoryMappedIONotSupportedException ex) {
Debug.WriteLine($"mmap'd IO didn't work: {ex.Message}");
}
catch (EntryPointNotFoundException) {
}
catch (DllNotFoundException) {
}
canTryUnix = false;
return(null);
}
public static void Mmap(MemoryMappedDataReaderFactory creator, bool mapAsImage)
{
using (var fileHandle = CreateFile(creator.filename, GENERIC_READ, FILE_SHARE_READ, IntPtr.Zero, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, IntPtr.Zero)) {
if (fileHandle.IsInvalid)
{
throw new IOException($"Could not open file {creator.filename} for reading. Error: {Marshal.GetLastWin32Error():X8}");
}
uint sizeLo = GetFileSize(fileHandle, out uint sizeHi);
int hr;
if (sizeLo == INVALID_FILE_SIZE && (hr = Marshal.GetLastWin32Error()) != NO_ERROR)
{
throw new IOException($"Could not get file size. File: {creator.filename}, error: {hr:X8}");
}
var fileSize = ((long)sizeHi << 32) | sizeLo;
using (var fileMapping = CreateFileMapping(fileHandle, IntPtr.Zero, PAGE_READONLY | (mapAsImage ? SEC_IMAGE : 0), 0, 0, null)) {
if (fileMapping.IsInvalid)
{
throw new MemoryMappedIONotSupportedException($"Could not create a file mapping object. File: {creator.filename}, error: {Marshal.GetLastWin32Error():X8}");
}
creator.data = MapViewOfFile(fileMapping, FILE_MAP_READ, 0, 0, UIntPtr.Zero);
if (creator.data == IntPtr.Zero)
{
throw new MemoryMappedIONotSupportedException($"Could not map file {creator.filename}. Error: {Marshal.GetLastWin32Error():X8}");
}
creator.length = (uint)fileSize;
creator.osType = OSType.Windows;
creator.stream = DataStreamFactory.Create((byte *)creator.data);
}
}
}
public static void Mmap(MemoryMappedDataReaderFactory creator, bool mapAsImage)
{
int fd = open(creator.filename, O_RDONLY);
try {
if (fd < 0)
{
throw new IOException($"Could not open file {creator.filename} for reading. Error: {fd}");
}
long size;
IntPtr data;
if (IntPtr.Size == 4)
{
size = lseek32(fd, 0, SEEK_END);
if (size == -1)
{
throw new MemoryMappedIONotSupportedException($"Could not get length of {creator.filename} (lseek failed): {Marshal.GetLastWin32Error()}");
}
data = mmap32(IntPtr.Zero, (IntPtr)size, PROT_READ, MAP_PRIVATE, fd, 0);
if (data == new IntPtr(-1) || data == IntPtr.Zero)
{
throw new MemoryMappedIONotSupportedException($"Could not map file {creator.filename}. Error: {Marshal.GetLastWin32Error()}");
}
}
else
{
size = lseek64(fd, 0, SEEK_END);
if (size == -1)
{
throw new MemoryMappedIONotSupportedException($"Could not get length of {creator.filename} (lseek failed): {Marshal.GetLastWin32Error()}");
}
data = mmap64(IntPtr.Zero, (IntPtr)size, PROT_READ, MAP_PRIVATE, fd, 0);
if (data == new IntPtr(-1) || data == IntPtr.Zero)
{
throw new MemoryMappedIONotSupportedException($"Could not map file {creator.filename}. Error: {Marshal.GetLastWin32Error()}");
}
}
creator.data = data;
creator.length = (uint)size;
creator.origDataLength = size;
creator.osType = OSType.Unix;
creator.stream = DataStreamFactory.Create((byte *)creator.data);
}
finally {
if (fd >= 0)
{
close(fd);
}
}
}
static DataReaderFactory CreateDataReaderFactory(string fileName, bool mapAsImage)
{
if (!isUnix)
{
return(MemoryMappedDataReaderFactory.CreateWindows(fileName, mapAsImage));
}
else
{
return(MemoryMappedDataReaderFactory.CreateUnix(fileName, mapAsImage));
}
}
internal static MemoryMappedDataReaderFactory CreateWindows(string filename, bool mapAsImage)
{
if (!canTryWindows)
{
return(null);
}
var creator = new MemoryMappedDataReaderFactory(GetFullPath(filename));
try {
Windows.Mmap(creator, mapAsImage);
return(creator);
}
catch (EntryPointNotFoundException) {
}
catch (DllNotFoundException) {
}
canTryWindows = false;
return(null);
}