private int GetFirstSegmentContaining(ulong address)
{
int lower = 0;
int upper = _segments.Length - 1;
while (lower <= upper)
{
int mid = (lower + upper) >> 1;
ElfProgramHeader segment = _segments[mid];
ulong virtualAddress = segment.VirtualAddress;
ulong virtualSize = segment.VirtualSize;
if (virtualAddress <= address && address < virtualAddress + virtualSize)
{
while (mid > 0 && address < _segments[mid - 1].VirtualAddress + _segments[mid - 1].VirtualSize)
{
mid--;
}
return(mid);
}
if (address < virtualAddress)
{
upper = mid - 1;
}
else
{
lower = mid + 1;
}
}
return(-1);
}
public ElfVirtualAddressSpace(ImmutableArray <ElfProgramHeader> segments, IAddressSpace addressSpace)
{
// FileSize == 0 means the segment isn't backed by any data
_segments = segments.Where(segment => segment.FileSize > 0).OrderBy(segment => segment.VirtualAddress).ThenBy(segment => segment.VirtualSize).ToArray();
ElfProgramHeader lastSegment = _segments[_segments.Length - 1];
Length = lastSegment.VirtualAddress + lastSegment.FileSize;
_addressSpace = addressSpace;
}
public int Read(ulong address, Span <byte> buffer)
{
if (address == 0 || buffer.Length == 0)
{
return(0);
}
int i = GetFirstSegmentContaining(address);
if (i < 0)
{
return(0);
}
int bytesRead = 0;
for (; i < _segments.Length; i++)
{
ElfProgramHeader segment = _segments[i];
ulong virtualAddress = segment.VirtualAddress;
ulong virtualSize = segment.VirtualSize;
if (virtualAddress > address)
{
break;
}
if (address >= virtualAddress + virtualSize)
{
continue;
}
ulong offset = address - virtualAddress;
int toRead = (int)Math.Min((ulong)(buffer.Length - bytesRead), virtualSize - offset);
Span <byte> slice = buffer.Slice(bytesRead, toRead);
int read = segment.AddressSpace.Read(offset, slice);
if (read < toRead)
{
break;
}
bytesRead += read;
if (bytesRead == buffer.Length)
{
break;
}
address += (uint)read;
}
return(bytesRead);
}
