From: Matt Brooks <mattbrooks@...>
Date: 2009-09-03T04:33:26+09:00
Subject: Re: confusing string parsing problem

7stud -- wrote:
> Matt Brooks wrote:
>> Also, I never made it clear but the string is in network byte order (big 
>> Endian)
> 
> data = ""
> 
> data << 0.chr << 3.chr     #2 bytes
> data << 0.chr << 0.chr     #2 bytes
> data << 1.chr              #1 byte
> data << "BFO" << 0.chr     #null terminated string
> data << "-8000" << "\000"  #null terminated string
> data << 0.chr << 0.chr     #2 bytes
> 
> p data
> 
> --output:--
> "\000\003\000\000\001BFO\000-8000\000\000\000"
> 
> results = data.unpack("n2CZ*Z*n")
> p results
> 
> --output:--
> [3, 0, 1, "BFO", "-8000", 0]



7stud, Wow that is an elegant way!  thank you for your time.  I do 
appreciate both responses very much.  The first one clued me into using 
unpack...correctly

I was just now excited to get my very verbose way to work, I will 
probably switch to how you are doing it.  Just for comment, here is what 
i just got working...


        #prints first 5 bytes formatted nicely
        writelog("Sub Element Message: #{bin_msg.inspect_detailed})")

        #How many pairs to iterate through
        writelog("Pairs to get: #{bin_msg.pairs}")

        times_iterated = 0
        while times_iterated < bin_msg.pairs

          #Get Value Name, variable length
          current_unpacked_char = 
bin_msg.optional_sub_elements.unpack("Z*")
          #Print it
          writelog("\n\nParam Value Name = #{current_unpacked_char}\n")
          #Remove Name from front of string
          bin_msg.optional_sub_elements = 
bin_msg.optional_sub_elements.sub(/^#{current_unpacked_char}\000/, '')

          #Get Value, variable length
          current_unpacked_char = 
bin_msg.optional_sub_elements.unpack("Z*")
          #Print it
          writelog("\n\nParam Value = #{current_unpacked_char}\n")
          #Remove Value from front of string
          bin_msg.optional_sub_elements = 
bin_msg.optional_sub_elements.sub(/^#{current_unpacked_char}\000/, '')

          #Get Last two byte value
          current_unpacked_char = 
bin_msg.optional_sub_elements.unpack("n")
          #Print it
          writelog("\n\nAudio Inversion Frequency = 
#{current_unpacked_char}\n")
          current_packed_char = current_unpacked_char.pack("n")
          #Remove Last two byte value
          bin_msg.optional_sub_elements = 
bin_msg.optional_sub_elements.sub(/^#{current_packed_char}/, '')

          times_iterated += 1
        end
-- 
Posted via http://www.ruby-forum.com/.