Mercurial > public > ostc4
annotate Discovery/Inc/crcmodel.h @ 818:40e951cfa443
1.6.4 release
author | heinrichsweikamp |
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date | Thu, 14 Sep 2023 13:24:30 +0200 |
parents | 45b8f3c2acce |
children |
rev | line source |
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38 | 1 /////////////////////////////////////////////////////////////////////////////// |
2 /// -*- coding: UTF-8 -*- | |
3 /// | |
4 /// \file Discovery/Inc/crcmodel.h | |
5 /// \brief Rocksoft CRC Model Algorithm | |
6 /// \author Ross Williams (ross@guest.adelaide.edu.au.) and Heinrichs Weikamp | |
7 /// \date 3 June 1993 | |
8 /// | |
9 /// \details | |
10 /// | |
11 /// This is the header (.h) file for the reference | |
12 /// implementation of the Rocksoft^tm Model CRC Algorithm. For more | |
13 /// information on the Rocksoft^tm Model CRC Algorithm, see the document | |
14 /// titled "A Painless Guide to CRC Error Detection Algorithms" by Ross | |
15 /// Williams (ross@guest.adelaide.edu.au.). This document is likely to be in | |
16 /// "ftp.adelaide.edu.au/pub/rocksoft". | |
17 /// | |
18 /// Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia. | |
19 /// | |
20 /// $Id$ | |
21 /////////////////////////////////////////////////////////////////////////////// | |
22 /// \par Copyright (c) 2014-2018 Heinrichs Weikamp gmbh | |
23 /// | |
24 /// This program is free software: you can redistribute it and/or modify | |
25 /// it under the terms of the GNU General Public License as published by | |
26 /// the Free Software Foundation, either version 3 of the License, or | |
27 /// (at your option) any later version. | |
28 /// | |
29 /// This program is distributed in the hope that it will be useful, | |
30 /// but WITHOUT ANY WARRANTY; without even the implied warranty of | |
31 /// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
32 /// GNU General Public License for more details. | |
33 /// | |
34 /// You should have received a copy of the GNU General Public License | |
35 /// along with this program. If not, see <http://www.gnu.org/licenses/>. | |
36 ////////////////////////////////////////////////////////////////////////////// | |
37 | |
38 /******************************************************************************/ | |
39 /* Start of crcmodel.h */ | |
40 /******************************************************************************/ | |
41 /* */ | |
42 /* Author : Ross Williams (ross@guest.adelaide.edu.au.). */ | |
43 /* Date : 3 June 1993. */ | |
44 /* Status : Public domain. */ | |
45 /* */ | |
46 /* Description : This is the header (.h) file for the reference */ | |
47 /* implementation of the Rocksoft^tm Model CRC Algorithm. For more */ | |
48 /* information on the Rocksoft^tm Model CRC Algorithm, see the document */ | |
49 /* titled "A Painless Guide to CRC Error Detection Algorithms" by Ross */ | |
50 /* Williams (ross@guest.adelaide.edu.au.). This document is likely to be in */ | |
51 /* "ftp.adelaide.edu.au/pub/rocksoft". */ | |
52 /* */ | |
53 /* Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia. */ | |
54 /* */ | |
55 /******************************************************************************/ | |
56 /* */ | |
57 /* How to Use This Package */ | |
58 /* ----------------------- */ | |
59 /* Step 1: Declare a variable of type cm_t. Declare another variable */ | |
60 /* (p_cm say) of type p_cm_t and initialize it to point to the first */ | |
61 /* variable (e.g. p_cm_t p_cm = &cm_t). */ | |
62 /* */ | |
63 /* Step 2: Assign values to the parameter fields of the structure. */ | |
64 /* If you don't know what to assign, see the document cited earlier. */ | |
65 /* For example: */ | |
66 /* p_cm->cm_width = 16; */ | |
67 /* p_cm->cm_poly = 0x8005L; */ | |
68 /* p_cm->cm_init = 0L; */ | |
69 /* p_cm->cm_refin = TRUE; */ | |
70 /* p_cm->cm_refot = TRUE; */ | |
71 /* p_cm->cm_xorot = 0L; */ | |
72 /* Note: Poly is specified without its top bit (18005 becomes 8005). */ | |
73 /* Note: Width is one bit less than the raw poly width. */ | |
74 /* */ | |
75 /* Step 3: Initialize the instance with a call cm_ini(p_cm); */ | |
76 /* */ | |
77 /* Step 4: Process zero or more message bytes by placing zero or more */ | |
78 /* successive calls to cm_nxt. Example: cm_nxt(p_cm,ch); */ | |
79 /* */ | |
80 /* Step 5: Extract the CRC value at any time by calling crc = cm_crc(p_cm); */ | |
81 /* If the CRC is a 16-bit value, it will be in the bottom 16 bits. */ | |
82 /* */ | |
83 /******************************************************************************/ | |
84 /* */ | |
85 /* Design Notes */ | |
86 /* ------------ */ | |
87 /* PORTABILITY: This package has been coded very conservatively so that */ | |
88 /* it will run on as many machines as possible. For example, all external */ | |
89 /* identifiers have been restricted to 6 characters and all internal ones to */ | |
90 /* 8 characters. The prefix cm (for Crc Model) is used as an attempt to avoid */ | |
91 /* namespace collisions. This package is endian independent. */ | |
92 /* */ | |
93 /* EFFICIENCY: This package (and its interface) is not designed for */ | |
94 /* speed. The purpose of this package is to act as a well-defined reference */ | |
95 /* model for the specification of CRC algorithms. If you want speed, cook up */ | |
96 /* a specific table-driven implementation as described in the document cited */ | |
97 /* above. This package is designed for validation only; if you have found or */ | |
98 /* implemented a CRC algorithm and wish to describe it as a set of parameters */ | |
99 /* to the Rocksoft^tm Model CRC Algorithm, your CRC algorithm implementation */ | |
100 /* should behave identically to this package under those parameters. */ | |
101 /* */ | |
102 /******************************************************************************/ | |
103 | |
104 #ifndef CRC_MODEL_H | |
105 #define CRC_MODEL_H | |
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 | |
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115 #include <stdbool.h> |
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116 |
38 | 117 typedef unsigned long ulong; |
118 typedef unsigned char * p_ubyte_; | |
119 | |
120 #ifndef TRUE | |
121 #define FALSE 0 | |
122 #define TRUE 1 | |
123 #endif | |
124 | |
125 /* Change to the second definition if you don't have prototypes. */ | |
126 #define P_(A) A | |
127 /* #define P_(A) () */ | |
128 | |
129 /* Uncomment this definition if you don't have void. */ | |
130 /* typedef int void; */ | |
131 | |
132 #endif | |
133 | |
134 /******************************************************************************/ | |
135 | |
136 /* CRC Model Abstract Type */ | |
137 /* ----------------------- */ | |
138 /* The following type stores the context of an executing instance of the */ | |
139 /* model algorithm. Most of the fields are model parameters which must be */ | |
140 /* set before the first initializing call to cm_ini. */ | |
141 typedef struct | |
142 { | |
143 int cm_width; /* Parameter: Width in bits [8,32]. */ | |
144 ulong cm_poly; /* Parameter: The algorithm's polynomial. */ | |
145 ulong cm_init; /* Parameter: Initial register value. */ | |
146 bool cm_refin; /* Parameter: Reflect input bytes? */ | |
147 bool cm_refot; /* Parameter: Reflect output CRC? */ | |
148 ulong cm_xorot; /* Parameter: XOR this to output CRC. */ | |
149 | |
150 ulong cm_reg; /* Context: Context during execution. */ | |
151 } cm_t; | |
152 typedef cm_t *p_cm_t; | |
153 | |
154 /******************************************************************************/ | |
155 | |
156 /* Functions That Implement The Model */ | |
157 /* ---------------------------------- */ | |
158 /* The following functions animate the cm_t abstraction. */ | |
159 | |
160 void cm_ini P_((p_cm_t p_cm)); | |
161 /* Initializes the argument CRC model instance. */ | |
162 /* All parameter fields must be set before calling this. */ | |
163 | |
164 void cm_nxt P_((p_cm_t p_cm,int ch)); | |
165 /* Processes a single message byte [0,255]. */ | |
166 | |
167 void cm_blk P_((p_cm_t p_cm,p_ubyte_ blk_adr,ulong blk_len)); | |
168 /* Processes a block of message bytes. */ | |
169 | |
170 ulong cm_crc P_((p_cm_t p_cm)); | |
171 /* Returns the CRC value for the message bytes processed so far. */ | |
172 | |
173 /******************************************************************************/ | |
174 | |
175 /* Functions For Table Calculation */ | |
176 /* ------------------------------- */ | |
177 /* The following function can be used to calculate a CRC lookup table. */ | |
178 /* It can also be used at run-time to create or check static tables. */ | |
179 | |
180 ulong cm_tab P_((p_cm_t p_cm,int index)); | |
181 /* Returns the i'th entry for the lookup table for the specified algorithm. */ | |
182 /* The function examines the fields cm_width, cm_poly, cm_refin, and the */ | |
183 /* argument table index in the range [0,255] and returns the table entry in */ | |
184 /* the bottom cm_width bytes of the return value. */ | |
185 | |
186 /******************************************************************************/ | |
187 | |
188 #endif // CRC_MODEL_H |