From: Charles Turner <vze26m98@...>
Date: 2008-08-21T23:02:50+09:00
Subject: Re: Ruby/DL: How to create and use a buffer?

On Thu, 21 Aug 2008 13:11:38 +0900, Charles Turner wrote:

> I'm trying to hookup Erik de Castro Lopo's libsndfile with Ruby via 
> Ruby/DL:

OK, responding to my own question because I think I've got it:

buffer = DL::CPtr.malloc(40)

frames = SndFile.sf_readf_int( sndfile, buffer, 10 )
frames   # => 10

buffer[0,40]   # => 
"qs\xDB\x8F`\x906\x8C\xF1\x16\x06\x89\x1C:M\x86X\xB5\x0E\x84\x9E\xC9L\x82\xE8:\t\x81\xB4OE\x80\x7F\xCA\x01\x80\xC7\xF1>\x80"

Seems to work fine. It appears that Ruby/DL isn't too happy with 
libsndfile's sf_readf_short() function, and in that case, my buffer 
seems to contain only the two MSBs of each 32-bit address. But I may 
still be doing something wrong.

Changing my audio file format to 32-bit integer data from 16-bit shows 
everything to be OK.

Best, Charles