OpenSolaris_b135/lib/libfru/libfruraw/crcmodel.h
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
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* or http://www.opensolaris.org/os/licensing.
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*
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/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#ifndef _CRCMODEL_H
#define _CRCMODEL_H
#ifdef SOLARIS_UNIX
#include <sys/types.h>
#else
typedef long uint32_t;
#endif
#ifdef __cplusplus
extern "C" {
#endif
/*
*
* Start of crcmodel.h
*
*
* Author : Ross Williams (ross@guest.adelaide.edu.au.).
* Date : 3 June 1993.
* Status : Public domain.
*
* Description : This is the header (.h) file for the reference
* implementation of the Rocksoft^tm Model CRC Algorithm. For more
* information on the Rocksoft^tm Model CRC Algorithm, see the document
* titled "A Painless Guide to CRC Error Detection Algorithms" by Ross
* Williams (ross@guest.adelaide.edu.au.). This document is likely to be in
* "ftp.adelaide.edu.au/pub/rocksoft".
*
* Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia.
*
*
*
* How to Use This Package
* -----------------------
* Step 1: Declare a variable of type cm_t. Declare another variable
* (p_cm say) of type p_cm_t and initialize it to point to the first
* variable (e.g. p_cm_t p_cm = &cm_t).
*
* Step 2: Assign values to the parameter fields of the structure.
* If you don't know what to assign, see the document cited earlier.
* For example:
* p_cm->cm_width = 16;
* p_cm->cm_poly = 0x8005L;
* p_cm->cm_init = 0L;
* p_cm->cm_refin = TRUE;
* p_cm->cm_refot = TRUE;
* p_cm->cm_xorot = 0L;
* Note: Poly is specified without its top bit (18005 becomes 8005).
* Note: Width is one bit less than the raw poly width.
*
* Step 3: Initialize the instance with a call cm_ini(p_cm);
*
* Step 4: Process zero or more message bytes by placing zero or more
* successive calls to cm_nxt. Example: cm_nxt(p_cm,ch);
*
* Step 5: Extract the CRC value at any time by calling crc = cm_crc(p_cm);
* If the CRC is a 16-bit value, it will be in the bottom 16 bits.
*
*
*
* Design Notes
* ------------
* PORTABILITY: This package has been coded very conservatively so that
* it will run on as many machines as possible. For example, all external
* identifiers have been restricted to 6 characters and all internal ones to
* 8 characters. The prefix cm (for Crc Model) is used as an attempt to avoid
* namespace collisions. This package is endian independent.
*
* EFFICIENCY: This package (and its interface) is not designed for
* speed. The purpose of this package is to act as a well-defined reference
* model for the specification of CRC algorithms. If you want speed, cook up
* a specific table-driven implementation as described in the document cited
* above. This package is designed for validation only; if you have found or
* implemented a CRC algorithm and wish to describe it as a set of parameters
* to the Rocksoft^tm Model CRC Algorithm, your CRC algorithm implementation
* should behave identically to this package under those parameters.
*
*/
/* The following definitions are extracted from my style header file which */
/* would be cumbersome to distribute with this package. The DONE_STYLE is the */
/* idempotence symbol used in my style header file. */
#ifndef DONE_STYLE
typedef unsigned bool;
typedef unsigned char *p_ubyte_;
#ifndef TRUE
#define FALSE 0
#define TRUE 1
#endif
/* Change to the second definition if you don't have prototypes. */
#define P_(A) A
/* #define P_(A) () */
/* Uncomment this definition if you don't have void. */
/* typedef int void; */
#endif
/* CRC Model Abstract Type */
/* ----------------------- */
/* The following type stores the context of an executing instance of the */
/* model algorithm. Most of the fields are model parameters which must be */
/* set before the first initializing call to cm_ini. */
typedef struct
{
int cm_width; /* Parameter: Width in bits [8,32]. */
uint32_t cm_poly; /* Parameter: The algorithm's polynomial. */
uint32_t cm_init; /* Parameter: Initial register value. */
bool cm_refin; /* Parameter: Reflect input bytes? */
bool cm_refot; /* Parameter: Reflect output CRC? */
uint32_t cm_xorot; /* Parameter: XOR this to output CRC. */
uint32_t cm_reg; /* Context: Context during execution. */
} cm_t;
typedef cm_t *p_cm_t;
/* Functions That Implement The Model */
/* ---------------------------------- */
/* The following functions animate the cm_t abstraction. */
void cm_ini P_((p_cm_t p_cm));
/* Initializes the argument CRC model instance. */
/* All parameter fields must be set before calling this. */
void cm_nxt P_((p_cm_t p_cm, int ch));
/* Processes a single message byte [0,255]. */
void cm_blk P_((p_cm_t p_cm, p_ubyte_ blk_adr, uint32_t blk_len));
/* Processes a block of message bytes. */
uint32_t cm_crc P_((p_cm_t p_cm));
/* Returns the CRC value for the message bytes processed so far. */
/* Functions For Table Calculation */
/* ------------------------------- */
/* The following function can be used to calculate a CRC lookup table. */
/* It can also be used at run-time to create or check static tables. */
uint32_t cm_tab P_((p_cm_t p_cm, int index));
/* Returns the i'th entry for the lookup table for the specified algorithm. */
/* The function examines the fields cm_width, cm_poly, cm_refin, and the */
/* argument table index in the range [0,255] and returns the table entry in */
/* the bottom cm_width bytes of the return value. */
#ifdef __cplusplus
}
#endif
#endif /* _CRCMODEL_H */