[phobos] stdin.byChunk seems broken

[Steven Schveighoffer]

I suggested having a range called duper on the ng to solve a similar problem with byLine. This range would call dup on each element. iduper probably be good too...

Sent from my new iPhone

On Jun 4, 2010, at 7:02 PM, Andrei Alexandrescu <andrei at erdani.com> wrote:

The reason is very simple - byChunk reuses the buffer for each chunk. That's why you are getting garbled data, and that's why you can't use immutable with byChunk.

There are two issues now:

1. send() should NEVER accept const(ubyte)[]. So you have a bug. The program as written shouldn't compile.

2. We need a sort of byImmutableChunk or something that creates a new buffer every pass, or simply recommend that people use .idup when they want to send stuff over.


Andrei

On 06/04/2010 05:48 PM, Sean Kelly wrote:
Given the sample:

    import std.algorithm, std.concurrency, std.stdio;


    void main()
    {
        enum bufferSize = 1;
        auto tid = spawn(&fileWriter );
        // Read loop
        /+ BUG: stdio can't handle the immutable buffer
        foreach( immutable(ubyte)[] buffer; stdin.byChunk( bufferSize ) )
            send( tid, buffer );
        +/
        foreach( const(ubyte)[] buffer; stdin.byChunk( bufferSize ) )
            send( tid, buffer );
    }


    void fileWriter()
    {
        // Write loop
        for( ; ; )
        {
            // BUG: stdio can't handle the immutable buffer
            //auto buffer = receiveOnly!(immutable(ubyte)[])();
            auto buffer = receiveOnly!(const(ubyte)[])();
            writeln( "rx: ", buffer.field[0] );
        }
    }

The output I see is:

   abacus:tdpl sean$ ch13_7
   aaaa
   rx: 10
   rx: 10
   rx: 10
   rx: 10
   rx: 10
   ^C
   abacus:tdpl sean$

Why if I send 4 'a' characters do I receive 5 \n characters?  Seems like the last character in the buffer is being copied over the preceding data.  I just thought I'd mention this in case someone has the time and inclination to look into it.
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