DataBuffer resizing

[HezkoreParticipant]

I’m trying to resize a DataBuffer, but it doesn’t seem to update properly?
In this example I’m resizing it to 8, but Length still returns 512

Monkey

Local buff:DataBuffer=New DataBuffer( 512 ) buff.Resize( 8 ) Print buff.Length

1 2 3 4

Local buff:DataBuffer=New DataBuffer( 512 ) buff.Resize( 8 ) Print buff.Length

[TomToadParticipant]

Here is the code in the source.

Monkey

Method Resize( length:Int ) Local data:=Cast<UByte Ptr>( GCMalloc( length ) ) libc.memcpy( data,_data,Min( length,_length ) ) GCFree( _data ) _data=data End

1 2 3 4 5 6

Method Resize( length:Int ) Local data:=Cast<UByte Ptr>( GCMalloc( length ) ) libc.memcpy( data,_data,Min( length,_length ) ) GCFree( _data ) _data=data End

As you can see, the buffer is being resized properly. The problem is that the _length field is not being updated, so it is reporting the wrong size (and could cause an error if you read or write outside the true length).
Should be a _length = length in there somewhere.

Edit: just submitted an issue on Github.

[HezkoreParticipant]

Thanks for the issue submit to Github.

I have loads of issues with DataBuffer.
For example, when using ‘server.ReceiveFrom’ with network sockets (seen in ‘banans/echoserver_udp’)

Monkey

If server.CanReceive>0 Then buffer=New DataBuffer( server.CanReceive+1 ) server.ReceiveFrom( Varptr buffer, server.CanReceive, addr ) Print buffer.PeekUByte( 0 ) Endif

1 2 3 4 5

If server.CanReceive>0 Then buffer=New DataBuffer( server.CanReceive+1 ) server.ReceiveFrom( Varptr buffer, server.CanReceive, addr ) Print buffer.PeekUByte( 0 ) Endif

I get this error:

MS DOS

Memory access violation {{!DEBUG!}} >PeekUByte:Ubyte(offset:Int);G:/tools/Monkey2/modules/std/memory/databuffer.monkey2;118;9267912 Self:std.memory.DataBuffer=@0159B65C offset:Int=0 >Main:Void();G:/code/monkey2/crawl/src/server/server.monkey2;28;135 server:std.socket.Socket=@0008F58C clients:std.collections.Map<std.socket.SocketAddress,Uint>=@0008F554 addr:std.socket.SocketAddress=@0008F7E4 buffer:std.memory.DataBuffer=@0159B65C

1 2 3 4 5 6 7 8 9 10

Memory access violation {{!DEBUG!}} >PeekUByte:Ubyte(offset:Int);G:/tools/Monkey2/modules/std/memory/databuffer.monkey2;118;9267912 Self:std.memory.DataBuffer=@0159B65C offset:Int=0 >Main:Void();G:/code/monkey2/crawl/src/server/server.monkey2;28;135 server:std.socket.Socket=@0008F58C clients:std.collections.Map<std.socket.SocketAddress,Uint>=@0008F554 addr:std.socket.SocketAddress=@0008F7E4 buffer:std.memory.DataBuffer=@0159B65C

Though I guess that could be a network socket issue and not a DataBuffer issue.
But it seems like whenever I use the DataBuffer, I run into some weird problem heh.

[TomToadParticipant]

Maybe possible that more data is received between lines 2 and 3 causing server.ReceiveFrom to read in more data than the buffer was originally allocated?
Maybe try something like this

Monkey

Local CanReceive:=server.CanReceive If CanReceive>0 Then buffer=New DataBuffer( CanReceive+1 ) server.ReceiveFrom( Varptr buffer, CanReceive, addr ) Print buffer.PeekUByte( 0 ) Endif

1 2 3 4 5 6

Local CanReceive:=server.CanReceive If CanReceive>0 Then buffer=New DataBuffer( CanReceive+1 ) server.ReceiveFrom( Varptr buffer, CanReceive, addr ) Print buffer.PeekUByte( 0 ) Endif

[Mark SiblyKeymaster]

Monkey

buffer=New DataBuffer( server.CanReceive+1 ) server.ReceiveFrom( Varptr buffer, server.CanReceive, addr )

1 2 3

buffer=New DataBuffer( server.CanReceive+1 ) server.ReceiveFrom( Varptr buffer, server.CanReceive, addr )

Danger! Use ‘buffer.Data’ to get a pointer to the data within a buffer, NOT ‘Varptr buffer’. Varptr buffer returns the address of the buffer object. The above code will completely destroy the contents of the ‘buffer’ reference.

‘Varptr object’ should really be illegal, and is likely to become so one day.

[HezkoreParticipant]

Okay good to know Mark!
Resize issue is still a problem though :/

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