I have a strange issue with TFileStream, just wondering if anything is known...
The function below is supposed to read the first (up to) 5000 bytes of a file. It works fine on "normal" sized files.
But I have a couple of files between 3 and 8 GB in size, and for those files read just returns buf filled with zeros.
The output shows, that fs.read returns 5000, that is it claims that the full amount has been read.
Smaller files on the same filesystem do work. there are no spaces in the filename or directory.
This happens on windows, fpc from trunc (older and today).
Show quoted text 31 lines
function TFileInfo.GetChecksum: Integer;
const
PRE_READ_SIZE = 5000;
var
c, i: Integer;
fs: TFileStream;
buf: Array [0..PRE_READ_SIZE] of Byte;
begin
if FChecksumDone then exit(FChecksum);
c := 0;
try
fs := TFileStream.Create(Dir + Name, fmOpenRead);
try
debugln(['## ',
fs.Read(buf[0], PRE_READ_SIZE)
]);
for i := 0 to PRE_READ_SIZE - 1 do begin
c := c + buf[i];
if i > 0 then
c := (c + (buf[i] * buf[i-1])) AND $7fffff;
end;
finally
fs.free;
end;
except
end;
debugln(['--- ',Name,' ',c]);
FChecksum := c;
FChecksumDone := True;
Result := FChecksum;
end;