<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello,<div><br></div><div>I'd like to quote one statement here: "<span class="Apple-style-span" style="font-family: arial, sans-serif; font-size: 12px; ">Network stacks and communication protocols must also define their endianness. Otherwise, two nodes of different endianness would be unable to communicate.</span>"</div><div>As an example, TCP/IP protocol suite is defined to be a big-endian. </div><div><br></div><div>So, the parsing of protocol primitive shall not be dependent on CPU architecture. E.g. If you protocol say that version is serialized into big-endian then your parsing code shall be same and it is platform independent. </div><div><br></div><div>- Dmitry</div><div><br></div><div>P.S: ;-) <a href="http://geekandpoke.typepad.com/geekandpoke/2011/09/simply-explained-1.html">http://geekandpoke.typepad.com/geekandpoke/2011/09/simply-explained-1.html</a></div><div><br></div><div><br><div><div>On May 12, 2012, at 10:34 AM, Arun Muralidharan wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><meta http-equiv="content-type" content="text/html; charset=utf-8"><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
Hi Folks,</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
I have an erlang application which includes parsing of binary data from socket (both TCP and UDP). The binary data is as per some specific protocol, so my options for TCP and UDP sock is as per below:</p><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
<br class="webkit-block-placeholder"></div><span class="Apple-style-span" style="font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; font-size: 14px; border-collapse: collapse; line-height: 18px; "><pre style="margin-top:0px;margin-right:0px;margin-bottom:10px;margin-left:0px;padding-top:5px;padding-right:5px;padding-bottom:5px;padding-left:5px;border-top-width:0px;border-right-width:0px;border-bottom-width:0px;border-left-width:0px;border-style:initial;border-color:initial;font-size:14px;vertical-align:baseline;background-image:initial;background-color:rgb(238,238,238);font-family:Consolas,Menlo,Monaco,'Lucida Console','Liberation Mono','DejaVu Sans Mono','Bitstream Vera Sans Mono','Courier New',monospace,serif;overflow-x:auto;overflow-y:auto;width:auto;max-height:600px;background-repeat:initial initial">TCP sock :
Opts = [binary, {packet, 0}, {reuseaddr, true},
{keepalive, true}, {backlog, 30}, {active, false}],
</pre></span><span class="Apple-style-span" style="font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; font-size: 14px; border-collapse: collapse; line-height: 18px; "><pre style="margin-top:0px;margin-right:0px;margin-bottom:10px;margin-left:0px;padding-top:5px;padding-right:5px;padding-bottom:5px;padding-left:5px;border-top-width:0px;border-right-width:0px;border-bottom-width:0px;border-left-width:0px;border-style:initial;border-color:initial;font-size:14px;vertical-align:baseline;background-image:initial;background-color:rgb(238,238,238);font-family:Consolas,Menlo,Monaco,'Lucida Console','Liberation Mono','DejaVu Sans Mono','Bitstream Vera Sans Mono','Courier New',monospace,serif;overflow-x:auto;overflow-y:auto;width:auto;max-height:600px;background-repeat:initial initial">UDP sock :
[binary,{active,once},{recbuf,2097152}]
</pre></span><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
<br class="webkit-block-placeholder"></div><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
Now, when i parse the data I get from socket, I do like this (On UNIX):</p><span class="Apple-style-span" style="font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; font-size: 14px; border-collapse: collapse; line-height: 18px; "><pre style="margin-top:0px;margin-right:0px;margin-bottom:10px;margin-left:0px;padding-top:5px;padding-right:5px;padding-bottom:5px;padding-left:5px;border-top-width:0px;border-right-width:0px;border-bottom-width:0px;border-left-width:0px;border-style:initial;border-color:initial;font-size:14px;vertical-align:baseline;background-image:initial;background-color:rgb(238,238,238);font-family:Consolas,Menlo,Monaco,'Lucida Console','Liberation Mono','DejaVu Sans Mono','Bitstream Vera Sans Mono','Courier New',monospace,serif;overflow-x:auto;overflow-y:auto;width:auto;max-height:600px;background-repeat:initial initial"> << Version:4/big-unsigned-integer-unit:8,
Length:2/big-unsigned-integer:8,
_Rest/binary >> = Bin_event_From_Socket.
</pre></span><span class="Apple-style-span" style="font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; font-size: 14px; border-collapse: collapse; line-height: 18px; ">Now, this would give me a problem when run on LINUX as LINUX is little endian based. So, the option here for me is to convert 'big' to 'little' in the above code.</span><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
<br class="webkit-block-placeholder"></div><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
But, Erlang being a VM based language, I must be having some facility to write platform independent code. I searched the NEt but couldnt find much on it.</p><span class="Apple-style-span" style="font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; font-size: 14px; border-collapse: collapse; line-height: 18px; ">So, the question here is how can i write a platform independent sockaet data parsing code ?</span><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
<br class="webkit-block-placeholder"></div><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 1em; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; font-size: 14px; vertical-align: baseline; background-image: initial; background-color: transparent; clear: both; word-wrap: break-word; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; border-collapse: collapse; line-height: 18px; ">
Thanks.</p>-Arun<br>
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