usr/src/lib/libfru/libfruraw/crcmodel.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #ifndef _CRCMODEL_H
  28 #define _CRCMODEL_H
  29
  30 #ifdef SOLARIS_UNIX
  31 #include <sys/types.h>
  32 #else
  33 typedef long uint32_t;
  34 #endif
  35
  36 #ifdef __cplusplus
  37 extern "C" {
  38 #endif
  39
  40 /*
  41  *
  42  *                             Start of crcmodel.h
  43  *
  44  *
  45  * Author : Ross Williams (ross@guest.adelaide.edu.au.).
  46  * Date   : 3 June 1993.
  47  * Status : Public domain.
  48  *
  49  * Description : This is the header (.h) file for the reference
  50  * implementation of the Rocksoft^tm Model CRC Algorithm. For more
  51  * information on the Rocksoft^tm Model CRC Algorithm, see the document
  52  * titled "A Painless Guide to CRC Error Detection Algorithms" by Ross
  53  * Williams (ross@guest.adelaide.edu.au.). This document is likely to be in
  54  * "ftp.adelaide.edu.au/pub/rocksoft".
  55  *
  56  * Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia.
  57  *
  58  *
  59  *
  60  * How to Use This Package
  61  * -----------------------
  62  * Step 1: Declare a variable of type cm_t. Declare another variable
  63  *         (p_cm say) of type p_cm_t and initialize it to point to the first
  64  *         variable (e.g. p_cm_t p_cm = &cm_t).
  65  *
  66  * Step 2: Assign values to the parameter fields of the structure.
  67  *         If you don't know what to assign, see the document cited earlier.
  68  *         For example:
  69  *            p_cm->cm_width = 16;
  70  *            p_cm->cm_poly  = 0x8005L;
  71  *            p_cm->cm_init  = 0L;
  72  *            p_cm->cm_refin = TRUE;
  73  *            p_cm->cm_refot = TRUE;
  74  *            p_cm->cm_xorot = 0L;
  75  *         Note: Poly is specified without its top bit (18005 becomes 8005).
  76  *         Note: Width is one bit less than the raw poly width.
  77  *
  78  * Step 3: Initialize the instance with a call cm_ini(p_cm);
  79  *
  80  * Step 4: Process zero or more message bytes by placing zero or more
  81  *         successive calls to cm_nxt. Example: cm_nxt(p_cm,ch);
  82  *
  83  * Step 5: Extract the CRC value at any time by calling crc = cm_crc(p_cm);
  84  *         If the CRC is a 16-bit value, it will be in the bottom 16 bits.
  85  *
  86  *
  87  *
  88  * Design Notes
  89  * ------------
  90  * PORTABILITY: This package has been coded very conservatively so that
  91  * it will run on as many machines as possible. For example, all external
  92  * identifiers have been restricted to 6 characters and all internal ones to
  93  * 8 characters. The prefix cm (for Crc Model) is used as an attempt to avoid
  94  * namespace collisions. This package is endian independent.
  95  *
  96  * EFFICIENCY: This package (and its interface) is not designed for
  97  * speed. The purpose of this package is to act as a well-defined reference
  98  * model for the specification of CRC algorithms. If you want speed, cook up
  99  * a specific table-driven implementation as described in the document cited
 100  * above. This package is designed for validation only; if you have found or
 101  * implemented a CRC algorithm and wish to describe it as a set of parameters
 102  * to the Rocksoft^tm Model CRC Algorithm, your CRC algorithm implementation
 103  * should behave identically to this package under those parameters.
 104  *
 105  */
 106
 107
 108 /* The following definitions are extracted from my style header file which */
 109 /* would be cumbersome to distribute with this package. The DONE_STYLE is the */
 110 /* idempotence symbol used in my style header file. */
 111
 112 #ifndef DONE_STYLE
 113
 114 typedef unsigned bool;
 115 typedef unsigned char *p_ubyte_;
 116
 117 #ifndef TRUE
 118 #define FALSE 0
 119 #define TRUE  1
 120 #endif
 121
 122 /* Change to the second definition if you don't have prototypes. */
 123 #define P_(A) A
 124 /* #define P_(A) () */
 125
 126 /* Uncomment this definition if you don't have void. */
 127 /* typedef int void; */
 128
 129 #endif
 130
 131 /* CRC Model Abstract Type */
 132 /* ----------------------- */
 133 /* The following type stores the context of an executing instance of the */
 134 /* model algorithm. Most of the fields are model parameters which must be */
 135 /* set before the first initializing call to cm_ini. */
 136 typedef struct
 137 {
 138         int cm_width; /* Parameter: Width in bits [8,32]. */
 139         uint32_t cm_poly; /* Parameter: The algorithm's polynomial. */
 140         uint32_t cm_init; /* Parameter: Initial register value. */
 141         bool cm_refin; /* Parameter: Reflect input bytes? */
 142         bool cm_refot; /* Parameter: Reflect output CRC? */
 143         uint32_t cm_xorot; /* Parameter: XOR this to output CRC. */
 144
 145         uint32_t cm_reg; /* Context: Context during execution. */
 146 } cm_t;
 147 typedef cm_t *p_cm_t;
 148
 149 /* Functions That Implement The Model */
 150 /* ---------------------------------- */
 151 /* The following functions animate the cm_t abstraction. */
 152
 153 void cm_ini P_((p_cm_t p_cm));
 154 /* Initializes the argument CRC model instance. */
 155 /* All parameter fields must be set before calling this. */
 156
 157 void cm_nxt P_((p_cm_t p_cm, int ch));
 158 /* Processes a single message byte [0,255]. */
 159
 160 void cm_blk P_((p_cm_t p_cm, p_ubyte_ blk_adr, uint32_t blk_len));
 161 /* Processes a block of message bytes. */
 162
 163 uint32_t cm_crc P_((p_cm_t p_cm));
 164 /* Returns the CRC value for the message bytes processed so far. */
 165
 166 /* Functions For Table Calculation */
 167 /* ------------------------------- */
 168 /* The following function can be used to calculate a CRC lookup table. */
 169 /* It can also be used at run-time to create or check static tables. */
 170
 171 uint32_t cm_tab P_((p_cm_t p_cm, int index));
 172 /* Returns the i'th entry for the lookup table for the specified algorithm. */
 173 /* The function examines the fields cm_width, cm_poly, cm_refin, and the */
 174 /* argument table index in the range [0,255] and returns the table entry in */
 175 /* the bottom cm_width bytes of the return value. */
 176
 177 #ifdef __cplusplus
 178 }
 179 #endif
 180
 181 #endif /* _CRCMODEL_H */