1 // Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 
7 //     http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #ifndef ROM_CRC_H
16 #define ROM_CRC_H
17 
18 #include <stdint.h>
19 
20 #ifdef __cplusplus
21 extern "C" {
22 #endif
23 
24 /** \defgroup crc_apis, uart configuration and communication related apis
25   * @brief crc apis
26   */
27 
28 /** @addtogroup crc_apis
29   * @{
30   */
31 
32 
33 /* Standard CRC8/16/32 algorithms. */
34 // CRC-8        x8+x2+x1+1              0x07
35 // CRC16-CCITT  x16+x12+x5+1   1021   ISO HDLC, ITU X.25, V.34/V.41/V.42, PPP-FCS
36 // CRC32:
37 //G(x) = x32 +x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x1 + 1
38 //If your buf is not continuous, you can use the first result to be the second parameter.
39 
40 /**
41   * @brief Crc32 value that is in little endian.
42   *
43   * @param  uint32_t crc : init crc value, use 0 at the first use.
44   *
45   * @param  uint8_t const *buf : buffer to start calculate crc.
46   *
47   * @param  uint32_t len : buffer length in byte.
48   *
49   * @return None
50   */
51 uint32_t crc32_le(uint32_t crc, uint8_t const *buf, uint32_t len);
52 
53 /**
54   * @brief Crc16 value that is in little endian.
55   *
56   * @param  uint16_t crc : init crc value, use 0 at the first use.
57   *
58   * @param  uint8_t const *buf : buffer to start calculate crc.
59   *
60   * @param  uint32_t len : buffer length in byte.
61   *
62   * @return None
63   */
64 uint16_t crc16_le(uint16_t crc, uint8_t const *buf, uint32_t len);
65 
66 /**
67   * @brief Crc8 value that is in little endian.
68   *
69   * @param  uint8_t crc : init crc value, use 0 at the first use.
70   *
71   * @param  uint8_t const *buf : buffer to start calculate crc.
72   *
73   * @param  uint32_t len : buffer length in byte.
74   *
75   * @return None
76   */
77 uint8_t crc8_le(uint8_t crc, uint8_t const *buf, uint32_t len);
78 
79 /**
80   * @}
81   */
82 
83 #ifdef __cplusplus
84 }
85 #endif
86 
87 
88 #endif
89