XLFCRC ICR (3156)

Name

Value

NUMBER

3156

IA #

3156

DATE CREATED

2000/08/04

CUSTODIAL PACKAGE

KERNEL

CUSTODIAL ISC

San Francisco

USAGE

Supported

TYPE

Routine

DBIC APPROVAL STATUS

APPROVED

ROUTINE

XLFCRC

NAME

XLFCRC

GENERAL DESCRIPTION

This routine has two API's, CRC32 and CRC16.

SET CRC=$$CRC32^XLFCRC(string)

A check-sum can also be calculated over multiple strings.
SET (I,C)=0
FOR  SET I=$ORDER(X(I)) QUIT:'I  DO
. SET C=$$CRC16^XLFCRC(X(I),C)

or
SET I=0,C=4294967295
FOR  SET I=$ORDER(X(I)) QUIT:'I  DO
. SET C=$$CRC32^XLFCRC(X(I),C)

as long as the save method is used all the time.

These have been approved for inclusion in a future ANSI M[UMPS] language
standard as part of the library.

STATUS

Active

KEYWORDS

CRC

XLFCRC

COMPONENT/ENTRY POINT

COMPONENT DESCRIPTION

VARIABLES

$$CRC32(string[,seed])

This function computes a Cyclic Redundance Code of
the 8-bit character string string, using X^32 + X^26 + X^23 + X^22 + X^16 +
X^12 + X^11 + X^10 + X^8 + X^7 + X^5 + X^4 + X^2 + X + 1 as the polynominal.
The optional parameter seed may supply an initial value, which allows for
running CRC calculations on multiple strings.  If the  parameter seed is not
specified, a default value of 4,294,967,295 (2^32-1) is assumed.  The value of
seed is limited to 0 <= seed <= 2^32.  The function value will be between 0
and 2^32.

VARIABLES	TYPE	VARIABLES DESCRIPTION
string	Input	String to compute the CRC32 on.
seed	Input	Optional seed value, Needed to compute the CRC32 over multiple strings.

$$CRC16(string[,seed])

This function computes a Cyclic Redundance Code of
the 8-bit character string string, using X^16 + X^15 + X^2 + 1as the
polynominal.  The optional parameter seed may supply an initial value, which
allows for running CRC calculations on multiple strings.  If the  parameter
seed is not specified, a default value of 0 is assumed. The value of seed is
limited to 0 <= seed <= 2^16.  The function value will be between 0 and 2^16.

VARIABLES	TYPE	VARIABLES DESCRIPTION
string	Input	String to compute the CRC16 on.
seed	Input	Optional seed value. Needed to compute the CRC16 over multiple strings.

DATE ACTIVATED

2007/11/06