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
33typedef long uint32_t;
34#endif
35
36#ifdef __cplusplus
37extern "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
114typedef unsigned bool;
115typedef 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. */
136typedef 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;
147typedef cm_t *p_cm_t;
148
149/* Functions That Implement The Model */
150/* ---------------------------------- */
151/* The following functions animate the cm_t abstraction. */
152
153void 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
157void cm_nxt P_((p_cm_t p_cm, int ch));
158/* Processes a single message byte [0,255]. */
159
160void cm_blk P_((p_cm_t p_cm, p_ubyte_ blk_adr, uint32_t blk_len));
161/* Processes a block of message bytes. */
162
163uint32_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
171uint32_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 */
182