Processing Bit Strings

From: Matt Taylor (para_at_tampabay.rr.com)
Date: 02/16/04

  • Next message: pawo: "perl 5.8.2/3 - thread started by a thread" 
    Date: Mon, 16 Feb 2004 09:15:12 GMT

    I have a script which runs postprocessing on some data and formats the
    results into a table. This is compiled into a C project. The perl script
    creates an 800x800 matrix of bits (~800 KB). After creating an enormously
    long string, it formats it for C source as follows:

    # Pad out the end of the bit string to a byte
    $bitstr .= '0' x ((8 - (length($bitstr) % 8)) % 8);

    # Create an array of bytes
    @bytes = ();
    while(length($bitstr) > 0)
    {
     push(@bytes, sprintf('0x%02X', ord(pack('b8', substr($bitstr, 0, 8)))));
     $bitstr = substr($bitstr, 8);
    }

    # Down here I have code to print the array

    This takes several minutes to run under perl 5.8 on my Pentium 4 2.53 GHz. I
    was wondering if there was a faster way to do this? Several minutes is
    usually acceptable, but in a debug cycle I run this script frequently, and
    it would make my life much easier if it were faster.

    -Matt

  • Next message: pawo: "perl 5.8.2/3 - thread started by a thread"

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