Posted by The Natural Philosopher on 09/27/07 14:11

Jerry Stuckle wrote:
> DM wrote:
>> "Erwin Moller"
>> <Since_humans_read_this_I_am_spammed_too_much@spamyourself.com> wrote
>> in message news:46fb87ea$0$244$e4fe514c@news.xs4all.nl...
>>> DM wrote:
>>>> Hi All,
>>>>
>>>> I'm writing a program that connects to a data stream containing a
>>>> number of
>>>> different variable types. Ie 4 & 8 byte integers, ASCII characters
>>>> and 8
>>>> byte floats.
>>>>
>>>> I use fgetc to capture the data in characters then I reconstruct the
>>>> variables from these bytes.
>>>>
>>>> For integers this is easy, just multiply the bytes by orders of 256
>>>> to get
>>>> the right offset values. The thing I can't figure out is how to
>>>> reconstruct
>>>> a double precision floating point number from its 8 component bytes.
>>>>
>>>> Is there an easy way to do this in PHP? I couldn't find anything
>>>> useful through
>>>> Google...
>>>>
>>>> Any pointers would be greatly appreciated.
>>>>
>>>> -DM
>>>>
>>> Hi DM,
>>>
>>> This data stream, where is it coming from?
>>> What program is producing it?
>>> Also PHP?
>>>
>>> Regards,
>>> Erwin Moller
>>
>> Hi Erwin, thanks for the reply.
>>
>> The data stream is coming from a custom Win32 Visual C++ real-time
>> server program which pumps out up to 1,000,000 of these multi-type
>> messages per day.
>>
>> I would like to grab and parse this data, then insert it into a
>> postgreSQL database under Linux rather than looking for a Windows
>> solution.
>>
>> I'm looking for a way to get this data into the postgres database so I
>> can utillise a whole suite of PHP diagnostic & analysis program I
>> wrote for another similar application.
>>
>> I had a look at the IEEE standard for double precision floats, but it
>> looks like I would have to do around 10-15 calculations per message to
>> manually restore the value. This would be impractical for the amount
>> of through-put I am facing...
>>
>> -DM
>>
>
> Personally, if I were looking at this much data, I'd be looking at a
> compiled language such as C/C++. If the data is coming in in binary,
> just stuff it in the appropriate bytes in a variable and you're done.
>
> Converting floating point variables is not fun, as you have found.
>
I'm leaning towards that too.
C, with its ability to cast anything to anything, makes a dynamite comms
type language.

Ive written apache/SQL shims in C before - its not really worse than PHP
- just a bit slower to debug.

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