[Issue 1953] New: BufferedFile seek and flush dumps 4gb to disk

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=1953

           Summary: BufferedFile seek and flush dumps 4gb to disk
           Product: D
           Version: 2.012
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: major
          Priority: P2
         Component: Phobos
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: regan at netmail.co.nz


The following code creates a 4gb+ size file on disk.  This appears to be the
result of a signed/unsigned problem inside a flush call somewhere in std.stream

import std.stdio;
import std.stream;
import std.file;
import std.random;

int main()
{
        // Create small file
        auto    f = new BufferedFile("test", FileMode.OutNew);
        int     size = 50000;

        for(int i = 0; i < size; i++)
                f.write('a');

        f.close;

        // Open and modify      
        f = new BufferedFile("test", FileMode.In | FileMode.Out);
        ulong   total = getSize("test");
        long    block = total/1000;
        long    offset;
        long    bytes;
        Random  gen;

        writefln("Total: %d,%d", total, block);

        for(int i = 0; i < 2; i++)
        {
                offset = uniform!(long)(gen, 0L, block);
                bytes  = uniform!(long)(gen, 0L, block);

                writefln("Seek : %d,%d,%d", f.position, offset, bytes);

                f.seekCur(offset);

                writefln("Mod  : %d,%d", f.position, bytes);

                for(long j = 0; j < bytes; j++)
                        f.write('\0');

                writefln("Done : %d", f.position);
        }

        writefln("Close: %d", f.position);

        f.close;

        writefln("Done");

        return 0;
}


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