/* | | Copyright disclaimer: |   This software was developed at the National Institute of Standards |   and Technology by employees of the Federal Government in the course |   of their official duties. Pursuant to title 17 Section 105 of the |   United States Code this software is not subject to copyright |   protection and is in the public domain. | |   We would appreciate acknowledgement if the software is used. |*//* | Project:     WCDMA simulation environment | Module:      Cyclic rendundance Check routines for different |              generator polynomials. | Author:      Tommi Makelainen | Date:        January 28, 1999 | | History: |              January 28, 1999 Tommi Makelainen |                      Initial version. | */#include <stdlib.h> #include <stdio.h>#include <math.h>#include "crc_routines.h"static unsigned short crctable[256];                  /* ----------------------------------------------------------- *//* * Init the fast CRC-16 calculation table. */void wcdma_crctable_init (int crc_gen_poly)  /* gen. polynomial as bit mask */{    int val, i;    unsigned int crc;    /*     * Calculate crc value for all possible input bytes.     */    for (val=0; val <= 255; val++) {        crc = val << 8;        for (i=0; i < 8; ++i) {	    crc <<= 1;	    if (crc & 0x10000) crc ^= crc_gen_poly;	}        crctable[val] = crc;    }    /*     * Check that int data type is a bit long.     */    if (sizeof(int) != 4) printf("crc init: size of int is not 32 bits.\n");} /* wcdma_crctable_init *//* ----------------------------------------------------------- *//* * Calculate CRC for 'input_data' having 'input_len' words (32-bit ones). *  * Note: int type must be 32-bit entity. */unsigned short wcdma_calc_crc(int *input_data, int input_len){    unsigned short crc_value = 0;    unsigned char data_byte;    int i;    while (input_len-- > 0) {        for (i=3; i > -1; i--) {            data_byte = (*input_data >> (8*i)) & 0xff;            crc_value = (crc_value<<8) ^ crctable[(crc_value>>8) ^ data_byte];        }        *input_data++;    }  return crc_value;} /* wcdma_calc_crc *//* ----------------------------------------------------------- *//* * Calculate CRC for 'input_data' having 'input_len' words (32-bit ones). *  * Note: *          int type must be 32-bit entity. *          Input data must be multiple of 8 bits (a byte). */unsigned short wcdma_get_crc_value(          int input_data[],  /* IN: input data bits */          int input_len,    /* IN: input data length */          int crc_bits[])   /* OUT: crc bits (MSB first) */{    unsigned short crc_value = 0;    unsigned char data_byte;    int i, j;    /*     * Loop over all input bits.     */    for (i=0; i < input_len; i += 8) {                /*         * Group input bits to a byte and find crc value for the byte.         */        data_byte = 0;        for (j=0; j < 8; j++) {            data_byte = (data_byte << 1) & 0xff;            data_byte = data_byte + ((unsigned char)input_data[i+j] & 0x1);        }        crc_value = (crc_value<<8) ^ crctable[(crc_value>>8) ^ data_byte];    }    /*     * Break down the result crc value to the output bit vector.     */    for (i=0,j=15; i < 16; i++,j--) {        crc_bits[i] = (crc_value >> j) & 0x1;    }    return crc_value;} /* wcdma_get_crc_value *//* ----------------------------------------------------------- */