wsutil/crc7.c

   1 /**
   2  * crc7.c
   3  *
   4  * Functions and types for CRC checks.
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11  *
  12  *
  13  * Generated on Wed Jul 11 17:24:30 2012,
  14  * by pycrc v0.7.10, http://www.tty1.net/pycrc/
  15  * using the configuration:
  16  *    Width        = 7
  17  *    Poly         = 0x45
  18  *    XorIn        = 0x00
  19  *    ReflectIn    = False
  20  *    XorOut       = 0x00
  21  *    ReflectOut   = False
  22  *    Algorithm    = table-driven
  23  *****************************************************************************/
  24 #include "config.h"
  25
  26 #include "crc7.h"     /* include the header file generated with pycrc */
  27
  28 /**
  29  * Static table used for the table_driven implementation.
  30  *****************************************************************************/
  31 static const uint8_t crc_table[256] = {
  32     0x00, 0x8a, 0x9e, 0x14, 0xb6, 0x3c, 0x28, 0xa2, 0xe6, 0x6c, 0x78, 0xf2, 0x50, 0xda, 0xce, 0x44,
  33     0x46, 0xcc, 0xd8, 0x52, 0xf0, 0x7a, 0x6e, 0xe4, 0xa0, 0x2a, 0x3e, 0xb4, 0x16, 0x9c, 0x88, 0x02,
  34     0x8c, 0x06, 0x12, 0x98, 0x3a, 0xb0, 0xa4, 0x2e, 0x6a, 0xe0, 0xf4, 0x7e, 0xdc, 0x56, 0x42, 0xc8,
  35     0xca, 0x40, 0x54, 0xde, 0x7c, 0xf6, 0xe2, 0x68, 0x2c, 0xa6, 0xb2, 0x38, 0x9a, 0x10, 0x04, 0x8e,
  36     0x92, 0x18, 0x0c, 0x86, 0x24, 0xae, 0xba, 0x30, 0x74, 0xfe, 0xea, 0x60, 0xc2, 0x48, 0x5c, 0xd6,
  37     0xd4, 0x5e, 0x4a, 0xc0, 0x62, 0xe8, 0xfc, 0x76, 0x32, 0xb8, 0xac, 0x26, 0x84, 0x0e, 0x1a, 0x90,
  38     0x1e, 0x94, 0x80, 0x0a, 0xa8, 0x22, 0x36, 0xbc, 0xf8, 0x72, 0x66, 0xec, 0x4e, 0xc4, 0xd0, 0x5a,
  39     0x58, 0xd2, 0xc6, 0x4c, 0xee, 0x64, 0x70, 0xfa, 0xbe, 0x34, 0x20, 0xaa, 0x08, 0x82, 0x96, 0x1c,
  40     0xae, 0x24, 0x30, 0xba, 0x18, 0x92, 0x86, 0x0c, 0x48, 0xc2, 0xd6, 0x5c, 0xfe, 0x74, 0x60, 0xea,
  41     0xe8, 0x62, 0x76, 0xfc, 0x5e, 0xd4, 0xc0, 0x4a, 0x0e, 0x84, 0x90, 0x1a, 0xb8, 0x32, 0x26, 0xac,
  42     0x22, 0xa8, 0xbc, 0x36, 0x94, 0x1e, 0x0a, 0x80, 0xc4, 0x4e, 0x5a, 0xd0, 0x72, 0xf8, 0xec, 0x66,
  43     0x64, 0xee, 0xfa, 0x70, 0xd2, 0x58, 0x4c, 0xc6, 0x82, 0x08, 0x1c, 0x96, 0x34, 0xbe, 0xaa, 0x20,
  44     0x3c, 0xb6, 0xa2, 0x28, 0x8a, 0x00, 0x14, 0x9e, 0xda, 0x50, 0x44, 0xce, 0x6c, 0xe6, 0xf2, 0x78,
  45     0x7a, 0xf0, 0xe4, 0x6e, 0xcc, 0x46, 0x52, 0xd8, 0x9c, 0x16, 0x02, 0x88, 0x2a, 0xa0, 0xb4, 0x3e,
  46     0xb0, 0x3a, 0x2e, 0xa4, 0x06, 0x8c, 0x98, 0x12, 0x56, 0xdc, 0xc8, 0x42, 0xe0, 0x6a, 0x7e, 0xf4,
  47     0xf6, 0x7c, 0x68, 0xe2, 0x40, 0xca, 0xde, 0x54, 0x10, 0x9a, 0x8e, 0x04, 0xa6, 0x2c, 0x38, 0xb2
  48 };
  49
  50
  51
  52 /**
  53  * Update the crc value with new data.
  54  *
  55  * \param crc      The current crc value.
  56  * \param data     Pointer to a buffer of \a data_len bytes.
  57  * \param data_len Number of bytes in the \a data buffer.
  58  * \return         The updated crc value.
  59  *****************************************************************************/
  60 uint8_t crc7update(uint8_t crc, const unsigned char *data, int data_len)
  61 {
  62     unsigned int tbl_idx;
  63
  64     while (data_len--) {
  65         tbl_idx = ((crc >> 0) ^ *data) & 0xff;
  66         crc = (crc_table[tbl_idx] ^ (crc << (8 - 1))) & (0x7f << 1);
  67
  68         data++;
  69     }
  70     return crc & (0x7f << 1);
  71 }
  72
  73 /*
  74  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
  75  *
  76  * Local variables:
  77  * c-basic-offset: 4
  78  * tab-width: 8
  79  * indent-tabs-mode: nil
  80  * End:
  81  *
  82  * vi: set shiftwidth=4 tabstop=8 expandtab:
  83  * :indentSize=4:tabSize=8:noTabs=true:
  84  */