[Boost-users] boost::crc - newbie help

Subject: [Boost-users] boost::crc - newbie help
From: Paul Caswell (Paul.Caswell_at_[hidden])
Date: 2010-01-08 06:35:38

Hello all,

I've the task of implementing the following CRC computation and was
wondering whether I could use boost::crc to save me a lot of hassle.  

 

------------------------

Default 32-bit Parity (CRC)

 

This 32-bit CRC is the same as that described in EKMS 304 ([6]) and EKMS
322 ([8]) and could be used as a CRC method in the keyAlgorithm
Attribute (with OID { 1 2 826 0 1145 0 5 1 }). Let g(x) be the
polynomial x32 + x22 + x2 + x + 1. Let d(x) be the k bits of data to
have parity applied to them. The first bit of data is the coefficient of
the (k-1)st power of x etc. Let f(x) be the polynomial naturally
represented by the initial fill 0xF8DD4258, i.e. x31 + x30 + x29 + x28 +
x27 + x23 + x22 + x20 + x19 + x18 + x16 + x14 + x9 + x6 + x4 + x3. Then
the output is

 

c(x) = x32d(x) + xkf(x) mod g(x).

 

The polynomial c(x) is then interpreted as a stream with the coefficient
of x31 coming first and the coefficient of x0 coming last. The 32-bit
parity is then c(x).

 

This calculation can be done using a simple shift register as shown
below. The shaded stages represent ones in the initial fill. The logic
steps k times to determine c(x), which is the final state of the
register.

<diagram omitted>

------------------------

 

Any advice and or help would be appreciated.

Regards,

Paul

 

 

 

 

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