From 4809f3c042a99a639542b1e6cd22657871113260 Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Fri, 2 Sep 2016 17:43:32 +0200 Subject: Move all sources to src/ --- src/lib_crc.c | 459 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 459 insertions(+) create mode 100644 src/lib_crc.c (limited to 'src/lib_crc.c') diff --git a/src/lib_crc.c b/src/lib_crc.c new file mode 100644 index 0000000..26b6b99 --- /dev/null +++ b/src/lib_crc.c @@ -0,0 +1,459 @@ +#include "lib_crc.h" + + + + /*******************************************************************\ + * * + * Library : lib_crc * + * File : lib_crc.c * + * Author : Lammert Bies 1999-2008 * + * E-mail : info@lammertbies.nl * + * Language : ANSI C * + * * + * * + * Description * + * =========== * + * * + * The file lib_crc.c contains the private and public func- * + * tions used for the calculation of CRC-16, CRC-CCITT and * + * CRC-32 cyclic redundancy values. * + * * + * * + * Dependencies * + * ============ * + * * + * lib_crc.h CRC definitions and prototypes * + * * + * * + * Modification history * + * ==================== * + * * + * Date Version Comment * + * * + * 2008-04-20 1.16 Added CRC-CCITT calculation for Kermit * + * * + * 2007-04-01 1.15 Added CRC16 calculation for Modbus * + * * + * 2007-03-28 1.14 Added CRC16 routine for Sick devices * + * * + * 2005-12-17 1.13 Added CRC-CCITT with initial 0x1D0F * + * * + * 2005-05-14 1.12 Added CRC-CCITT with start value 0 * + * * + * 2005-02-05 1.11 Fixed bug in CRC-DNP routine * + * * + * 2005-02-04 1.10 Added CRC-DNP routines * + * * + * 1999-02-21 1.01 Added FALSE and TRUE mnemonics * + * * + * 1999-01-22 1.00 Initial source * + * * + \*******************************************************************/ + + + + /*******************************************************************\ + * * + * #define P_xxxx * + * * + * The CRC's are computed using polynomials. The coefficients * + * for the algorithms are defined by the following constants. * + * * + \*******************************************************************/ + +#define P_16 0xA001 +#define P_32 0xEDB88320L +#define P_CCITT 0x1021 +#define P_DNP 0xA6BC +#define P_KERMIT 0x8408 +#define P_SICK 0x8005 + + + + /*******************************************************************\ + * * + * static int crc_tab...init * + * static unsigned ... crc_tab...[] * + * * + * The algorithms use tables with precalculated values. This * + * speeds up the calculation dramaticaly. The first time the * + * CRC function is called, the table for that specific calcu- * + * lation is set up. The ...init variables are used to deter- * + * mine if the initialization has taken place. The calculated * + * values are stored in the crc_tab... arrays. * + * * + * The variables are declared static. This makes them invisi- * + * ble for other modules of the program. * + * * + \*******************************************************************/ + +static int crc_tab16_init = FALSE; +static int crc_tab32_init = FALSE; +static int crc_tabccitt_init = FALSE; +static int crc_tabdnp_init = FALSE; +static int crc_tabkermit_init = FALSE; + +static unsigned short crc_tab16[256]; +static unsigned long crc_tab32[256]; +static unsigned short crc_tabccitt[256]; +static unsigned short crc_tabdnp[256]; +static unsigned short crc_tabkermit[256]; + + + + /*******************************************************************\ + * * + * static void init_crc...tab(); * + * * + * Three local functions are used to initialize the tables * + * with values for the algorithm. * + * * + \*******************************************************************/ + +static void init_crc16_tab( void ); +static void init_crc32_tab( void ); +static void init_crcccitt_tab( void ); +static void init_crcdnp_tab( void ); +static void init_crckermit_tab( void ); + + + + /*******************************************************************\ + * * + * unsigned short update_crc_ccitt( unsigned long crc, char c ); * + * * + * The function update_crc_ccitt calculates a new CRC-CCITT * + * value based on the previous value of the CRC and the next * + * byte of the data to be checked. * + * * + \*******************************************************************/ + +unsigned short update_crc_ccitt( unsigned short crc, char c ) { + + unsigned short tmp, short_c; + + short_c = 0x00ff & (unsigned short) c; + + if ( ! crc_tabccitt_init ) init_crcccitt_tab(); + + tmp = (crc >> 8) ^ short_c; + crc = (crc << 8) ^ crc_tabccitt[tmp]; + + return crc; + +} /* update_crc_ccitt */ + + + + /*******************************************************************\ + * * + * unsigned short update_crc_sick( * + * unsigned long crc, char c, char prev_byte ); * + * * + * The function update_crc_sick calculates a new CRC-SICK * + * value based on the previous value of the CRC and the next * + * byte of the data to be checked. * + * * + \*******************************************************************/ + +unsigned short update_crc_sick( unsigned short crc, char c, char prev_byte ) { + + unsigned short short_c, short_p; + + short_c = 0x00ff & (unsigned short) c; + short_p = ( 0x00ff & (unsigned short) prev_byte ) << 8; + + if ( crc & 0x8000 ) crc = ( crc << 1 ) ^ P_SICK; + else crc = crc << 1; + + crc &= 0xffff; + crc ^= ( short_c | short_p ); + + return crc; + +} /* update_crc_sick */ + + + + /*******************************************************************\ + * * + * unsigned short update_crc_16( unsigned short crc, char c ); * + * * + * The function update_crc_16 calculates a new CRC-16 value * + * based on the previous value of the CRC and the next byte * + * of the data to be checked. * + * * + \*******************************************************************/ + +unsigned short update_crc_16( unsigned short crc, char c ) { + + unsigned short tmp, short_c; + + short_c = 0x00ff & (unsigned short) c; + + if ( ! crc_tab16_init ) init_crc16_tab(); + + tmp = crc ^ short_c; + crc = (crc >> 8) ^ crc_tab16[ tmp & 0xff ]; + + return crc; + +} /* update_crc_16 */ + + + + /*******************************************************************\ + * * + * unsigned short update_crc_kermit( unsigned short crc, char c ); * + * * + * The function update_crc_kermit calculates a new CRC value * + * based on the previous value of the CRC and the next byte * + * of the data to be checked. * + * * + \*******************************************************************/ + +unsigned short update_crc_kermit( unsigned short crc, char c ) { + + unsigned short tmp, short_c; + + short_c = 0x00ff & (unsigned short) c; + + if ( ! crc_tabkermit_init ) init_crckermit_tab(); + + tmp = crc ^ short_c; + crc = (crc >> 8) ^ crc_tabkermit[ tmp & 0xff ]; + + return crc; + +} /* update_crc_kermit */ + + + + /*******************************************************************\ + * * + * unsigned short update_crc_dnp( unsigned short crc, char c ); * + * * + * The function update_crc_dnp calculates a new CRC-DNP value * + * based on the previous value of the CRC and the next byte * + * of the data to be checked. * + * * + \*******************************************************************/ + +unsigned short update_crc_dnp( unsigned short crc, char c ) { + + unsigned short tmp, short_c; + + short_c = 0x00ff & (unsigned short) c; + + if ( ! crc_tabdnp_init ) init_crcdnp_tab(); + + tmp = crc ^ short_c; + crc = (crc >> 8) ^ crc_tabdnp[ tmp & 0xff ]; + + return crc; + +} /* update_crc_dnp */ + + + + /*******************************************************************\ + * * + * unsigned long update_crc_32( unsigned long crc, char c ); * + * * + * The function update_crc_32 calculates a new CRC-32 value * + * based on the previous value of the CRC and the next byte * + * of the data to be checked. * + * * + \*******************************************************************/ + +unsigned long update_crc_32( unsigned long crc, char c ) { + + unsigned long tmp, long_c; + + long_c = 0x000000ffL & (unsigned long) c; + + if ( ! crc_tab32_init ) init_crc32_tab(); + + tmp = crc ^ long_c; + crc = (crc >> 8) ^ crc_tab32[ tmp & 0xff ]; + + return crc; + +} /* update_crc_32 */ + + + + /*******************************************************************\ + * * + * static void init_crc16_tab( void ); * + * * + * The function init_crc16_tab() is used to fill the array * + * for calculation of the CRC-16 with values. * + * * + \*******************************************************************/ + +static void init_crc16_tab( void ) { + + int i, j; + unsigned short crc, c; + + for (i=0; i<256; i++) { + + crc = 0; + c = (unsigned short) i; + + for (j=0; j<8; j++) { + + if ( (crc ^ c) & 0x0001 ) crc = ( crc >> 1 ) ^ P_16; + else crc = crc >> 1; + + c = c >> 1; + } + + crc_tab16[i] = crc; + } + + crc_tab16_init = TRUE; + +} /* init_crc16_tab */ + + + + /*******************************************************************\ + * * + * static void init_crckermit_tab( void ); * + * * + * The function init_crckermit_tab() is used to fill the array * + * for calculation of the CRC Kermit with values. * + * * + \*******************************************************************/ + +static void init_crckermit_tab( void ) { + + int i, j; + unsigned short crc, c; + + for (i=0; i<256; i++) { + + crc = 0; + c = (unsigned short) i; + + for (j=0; j<8; j++) { + + if ( (crc ^ c) & 0x0001 ) crc = ( crc >> 1 ) ^ P_KERMIT; + else crc = crc >> 1; + + c = c >> 1; + } + + crc_tabkermit[i] = crc; + } + + crc_tabkermit_init = TRUE; + +} /* init_crckermit_tab */ + + + + /*******************************************************************\ + * * + * static void init_crcdnp_tab( void ); * + * * + * The function init_crcdnp_tab() is used to fill the array * + * for calculation of the CRC-DNP with values. * + * * + \*******************************************************************/ + +static void init_crcdnp_tab( void ) { + + int i, j; + unsigned short crc, c; + + for (i=0; i<256; i++) { + + crc = 0; + c = (unsigned short) i; + + for (j=0; j<8; j++) { + + if ( (crc ^ c) & 0x0001 ) crc = ( crc >> 1 ) ^ P_DNP; + else crc = crc >> 1; + + c = c >> 1; + } + + crc_tabdnp[i] = crc; + } + + crc_tabdnp_init = TRUE; + +} /* init_crcdnp_tab */ + + + + /*******************************************************************\ + * * + * static void init_crc32_tab( void ); * + * * + * The function init_crc32_tab() is used to fill the array * + * for calculation of the CRC-32 with values. * + * * + \*******************************************************************/ + +static void init_crc32_tab( void ) { + + int i, j; + unsigned long crc; + + for (i=0; i<256; i++) { + + crc = (unsigned long) i; + + for (j=0; j<8; j++) { + + if ( crc & 0x00000001L ) crc = ( crc >> 1 ) ^ P_32; + else crc = crc >> 1; + } + + crc_tab32[i] = crc; + } + + crc_tab32_init = TRUE; + +} /* init_crc32_tab */ + + + + /*******************************************************************\ + * * + * static void init_crcccitt_tab( void ); * + * * + * The function init_crcccitt_tab() is used to fill the array * + * for calculation of the CRC-CCITT with values. * + * * + \*******************************************************************/ + +static void init_crcccitt_tab( void ) { + + int i, j; + unsigned short crc, c; + + for (i=0; i<256; i++) { + + crc = 0; + c = ((unsigned short) i) << 8; + + for (j=0; j<8; j++) { + + if ( (crc ^ c) & 0x8000 ) crc = ( crc << 1 ) ^ P_CCITT; + else crc = crc << 1; + + c = c << 1; + } + + crc_tabccitt[i] = crc; + } + + crc_tabccitt_init = TRUE; + +} /* init_crcccitt_tab */ -- cgit v1.2.3