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, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 *
22 * Copyright 2000 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26#ifndef	_CRCMODEL_H
27#define	_CRCMODEL_H
28
29#pragma ident	"%Z%%M%	%I%	%E% SMI"
30
31#ifdef SOLARIS_UNIX
32#include <sys/types.h>
33#else
34typedef long uint32_t;
35#endif
36
37#ifdef __cplusplus
38extern "C" {
39#endif
40
41/*
42 *
43 *                             Start of crcmodel.h
44 *
45 *
46 * Author : Ross Williams (ross@guest.adelaide.edu.au.).
47 * Date   : 3 June 1993.
48 * Status : Public domain.
49 *
50 * Description : This is the header (.h) file for the reference
51 * implementation of the Rocksoft^tm Model CRC Algorithm. For more
52 * information on the Rocksoft^tm Model CRC Algorithm, see the document
53 * titled "A Painless Guide to CRC Error Detection Algorithms" by Ross
54 * Williams (ross@guest.adelaide.edu.au.). This document is likely to be in
55 * "ftp.adelaide.edu.au/pub/rocksoft".
56 *
57 * Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia.
58 *
59 *
60 *
61 * How to Use This Package
62 * -----------------------
63 * Step 1: Declare a variable of type cm_t. Declare another variable
64 *         (p_cm say) of type p_cm_t and initialize it to point to the first
65 *         variable (e.g. p_cm_t p_cm = &cm_t).
66 *
67 * Step 2: Assign values to the parameter fields of the structure.
68 *         If you don't know what to assign, see the document cited earlier.
69 *         For example:
70 *            p_cm->cm_width = 16;
71 *            p_cm->cm_poly  = 0x8005L;
72 *            p_cm->cm_init  = 0L;
73 *            p_cm->cm_refin = TRUE;
74 *            p_cm->cm_refot = TRUE;
75 *            p_cm->cm_xorot = 0L;
76 *         Note: Poly is specified without its top bit (18005 becomes 8005).
77 *         Note: Width is one bit less than the raw poly width.
78 *
79 * Step 3: Initialize the instance with a call cm_ini(p_cm);
80 *
81 * Step 4: Process zero or more message bytes by placing zero or more
82 *         successive calls to cm_nxt. Example: cm_nxt(p_cm,ch);
83 *
84 * Step 5: Extract the CRC value at any time by calling crc = cm_crc(p_cm);
85 *         If the CRC is a 16-bit value, it will be in the bottom 16 bits.
86 *
87 *
88 *
89 * Design Notes
90 * ------------
91 * PORTABILITY: This package has been coded very conservatively so that
92 * it will run on as many machines as possible. For example, all external
93 * identifiers have been restricted to 6 characters and all internal ones to
94 * 8 characters. The prefix cm (for Crc Model) is used as an attempt to avoid
95 * namespace collisions. This package is endian independent.
96 *
97 * EFFICIENCY: This package (and its interface) is not designed for
98 * speed. The purpose of this package is to act as a well-defined reference
99 * model for the specification of CRC algorithms. If you want speed, cook up
100 * a specific table-driven implementation as described in the document cited
101 * above. This package is designed for validation only; if you have found or
102 * implemented a CRC algorithm and wish to describe it as a set of parameters
103 * to the Rocksoft^tm Model CRC Algorithm, your CRC algorithm implementation
104 * should behave identically to this package under those parameters.
105 *
106 */
107
108
109/* The following definitions are extracted from my style header file which */
110/* would be cumbersome to distribute with this package. The DONE_STYLE is the */
111/* idempotence symbol used in my style header file. */
112
113#ifndef DONE_STYLE
114
115typedef unsigned bool;
116typedef unsigned char *p_ubyte_;
117
118#ifndef TRUE
119#define	FALSE 0
120#define	TRUE  1
121#endif
122
123/* Change to the second definition if you don't have prototypes. */
124#define	P_(A) A
125/* #define P_(A) () */
126
127/* Uncomment this definition if you don't have void. */
128/* typedef int void; */
129
130#endif
131
132/* CRC Model Abstract Type */
133/* ----------------------- */
134/* The following type stores the context of an executing instance of the */
135/* model algorithm. Most of the fields are model parameters which must be */
136/* set before the first initializing call to cm_ini. */
137typedef struct
138{
139	int cm_width; /* Parameter: Width in bits [8,32]. */
140	uint32_t cm_poly; /* Parameter: The algorithm's polynomial. */
141	uint32_t cm_init; /* Parameter: Initial register value. */
142	bool cm_refin; /* Parameter: Reflect input bytes? */
143	bool cm_refot; /* Parameter: Reflect output CRC? */
144	uint32_t cm_xorot; /* Parameter: XOR this to output CRC. */
145
146	uint32_t cm_reg; /* Context: Context during execution. */
147} cm_t;
148typedef cm_t *p_cm_t;
149
150/* Functions That Implement The Model */
151/* ---------------------------------- */
152/* The following functions animate the cm_t abstraction. */
153
154void cm_ini P_((p_cm_t p_cm));
155/* Initializes the argument CRC model instance. */
156/* All parameter fields must be set before calling this. */
157
158void cm_nxt P_((p_cm_t p_cm, int ch));
159/* Processes a single message byte [0,255]. */
160
161void cm_blk P_((p_cm_t p_cm, p_ubyte_ blk_adr, uint32_t blk_len));
162/* Processes a block of message bytes. */
163
164uint32_t cm_crc P_((p_cm_t p_cm));
165/* Returns the CRC value for the message bytes processed so far. */
166
167/* Functions For Table Calculation */
168/* ------------------------------- */
169/* The following function can be used to calculate a CRC lookup table. */
170/* It can also be used at run-time to create or check static tables. */
171
172uint32_t cm_tab P_((p_cm_t p_cm, int index));
173/* Returns the i'th entry for the lookup table for the specified algorithm. */
174/* The function examines the fields cm_width, cm_poly, cm_refin, and the */
175/* argument table index in the range [0,255] and returns the table entry in */
176/* the bottom cm_width bytes of the return value. */
177
178#ifdef __cplusplus
179}
180#endif
181
182#endif /* _CRCMODEL_H */
183