[ruby-talk:7079] Re: Reading lots of binary data into arrays

In message <[e-mail]>
[e-mail] writes:

> |1)  Are there packages/extensions/modules available
> |    for reading large amounts of binary data into arrays
> |    of structures?  I know that binary data can be read
> |    a "char" at a time, but this is likely to be too
> |    slow.
> 
> Read fixed sized string using IO#read then unpack it into integers
> using String#unpack.  For example:
> 
>   input = open(path_to_file, "r")
>   ary = []
>   size_of_an_entry = (32*3+2*16)/8
>   
>   while str = input.read(size_of_an_entry)
>     ary.push(str.unpack("NNNnn")) # assuming network byte order
>   end

NOTE: If your application will run long time, you may experience a
performance problem.  This is caused by memory usage.  Since reading
data from IO always make a new object --- which is large in your
application? --- garbaged old input will trigger GC too many time.

You may need to write an extension which can reading data into a fixed
buffer, like my toy program.
<http://www.os.xaxon.ne.jp/~kjana/ruby/read_in.tar.gz>

# Uh, it's not so proven since what I wanted was a runnable example
# states my proposal :-P  ....Well, fixed buffer reading was proposed
# once on past....


-- 
[e-mail]                              December 12, 2000
Translators, traitors.