/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (the "License"). You may not use this file except in compliance * with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END * * Copyright 2000 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #ifndef _CRCMODEL_H #define _CRCMODEL_H #ifdef SOLARIS_UNIX #include #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 */