/*******************************************************************************
 * $Id$
 * Copyright 2004, Broadcom Corporation      
 * All Rights Reserved.      
 *       
 * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY      
 * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM      
 * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS      
 * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.      
 * crc.c: utility function to compute various CRCs
 ******************************************************************************/

#include "typedefs.h"
#include "crc.h"

/*******************************************************************************
 * hcs
 *
 * Computes and inserts a header check sum based on crc8 polynomial
 * below.  Unlike a typical crc, the header check sum is inserted 13
 * bytes from the end of the byte stream (rather than appended to the
 * end of the byte stream) such that at the receiver a normal checksum
 * computation over all of the bytes results in a known good value.
 * Given a constant 12 bytes after the header checksum to the end of
 * the header, a lookup table can be used to provide the actual value
 * inserted.
 ******************************************************************************/

static uint8 hcs_table[8] = { 0x16, 0x2c, 0x58, 0xb0, 0x37, 0x6e, 0xdc, 0xef};

void
hcs(
    uint8 *pheader, /* pointer to array of data to process */
    uint nbytes   /* number of input data bytes to process */
)
{
    uint8 hcs0, hcs1;
    int i;

    /* run once with zeros in hcs position, 13th byte from the end */
    pheader[nbytes - 12 - 1] = 0;
    hcs0 = crc8(pheader, nbytes, CRC8_INIT_VALUE);
 
    /* now compute real hcs to insert in place of zeros */
    hcs1 = 0;
    for (i = 0; i < 8; i++) {
        hcs1 ^= ((hcs0 & (1 << i)) != 0 ? hcs_table[i] : 0);
    }
    pheader[nbytes - 12 - 1] = hcs1 ^ 0xff;
    return;
}

/*******************************************************************************
 * crc8
 *
 * Computes a crc8 over the input data using the polynomial:
 *
 *       x^8 + x^7 +x^6 + x^4 + x^2 + 1
 *
 * The caller provides the initial value (either CRC8_INIT_VALUE
 * or the previous returned value) to allow for processing of 
 * discontiguous blocks of data.  When generating the CRC the
 * caller is responsible for complementing the final return value
 * and inserting it into the byte stream.  When checking, a final
 * return value of CRC8_GOOD_VALUE indicates a valid CRC.
 *
 * Reference: Dallas Semiconductor Application Note 27
 *   Williams, Ross N., "A Painless Guide to CRC Error Detection Algorithms", 
 *     ver 3, Aug 1993, ross@guest.adelaide.edu.au, Rocksoft Pty Ltd.,
 *     ftp://ftp.rocksoft.com/clients/rocksoft/papers/crc_v3.txt
 *
 ******************************************************************************/

static uint8 crc8_table[256] = {
    0x00, 0xF7, 0xB9, 0x4E, 0x25, 0xD2, 0x9C, 0x6B,
    0x4A, 0xBD, 0xF3, 0x04, 0x6F, 0x98, 0xD6, 0x21,
    0x94, 0x63, 0x2D, 0xDA, 0xB1, 0x46, 0x08, 0xFF,
    0xDE, 0x29, 0x67, 0x90, 0xFB, 0x0C, 0x42, 0xB5,
    0x7F, 0x88, 0xC6, 0x31, 0x5A, 0xAD, 0xE3, 0x14,
    0x35, 0xC2, 0x8C, 0x7B, 0x10, 0xE7, 0xA9, 0x5E,
    0xEB, 0x1C, 0x52, 0xA5, 0xCE, 0x39, 0x77, 0x80,
    0xA1, 0x56, 0x18, 0xEF, 0x84, 0x73, 0x3D, 0xCA,
    0xFE, 0x09, 0x47, 0xB0, 0xDB, 0x2C, 0x62, 0x95,
    0xB4, 0x43, 0x0D, 0xFA, 0x91, 0x66, 0x28, 0xDF,
    0x6A, 0x9D, 0xD3, 0x24, 0x4F, 0xB8, 0xF6, 0x01,
    0x20, 0xD7, 0x99, 0x6E, 0x05, 0xF2, 0xBC, 0x4B,
    0x81, 0x76, 0x38, 0xCF, 0xA4, 0x53, 0x1D, 0xEA,
    0xCB, 0x3C, 0x72, 0x85, 0xEE, 0x19, 0x57, 0xA0,
    0x15, 0xE2, 0xAC, 0x5B, 0x30, 0xC7, 0x89, 0x7E,
    0x5F, 0xA8, 0xE6, 0x11, 0x7A, 0x8D, 0xC3, 0x34,
    0xAB, 0x5C, 0x12, 0xE5, 0x8E, 0x79, 0x37, 0xC0,
    0xE1, 0x16, 0x58, 0xAF, 0xC4, 0x33, 0x7D, 0x8A,
    0x3F, 0xC8, 0x86, 0x71, 0x1A, 0xED, 0xA3, 0x54,
    0x75, 0x82, 0xCC, 0x3B, 0x50, 0xA7, 0xE9, 0x1E,
    0xD4, 0x23, 0x6D, 0x9A, 0xF1, 0x06, 0x48, 0xBF,
    0x9E, 0x69, 0x27, 0xD0, 0xBB, 0x4C, 0x02, 0xF5,
    0x40, 0xB7, 0xF9, 0x0E, 0x65, 0x92, 0xDC, 0x2B,
    0x0A, 0xFD, 0xB3, 0x44, 0x2F, 0xD8, 0x96, 0x61,
    0x55, 0xA2, 0xEC, 0x1B, 0x70, 0x87, 0xC9, 0x3E,
    0x1F, 0xE8, 0xA6, 0x51, 0x3A, 0xCD, 0x83, 0x74,
    0xC1, 0x36, 0x78, 0x8F, 0xE4, 0x13, 0x5D, 0xAA,
    0x8B, 0x7C, 0x32, 0xC5, 0xAE, 0x59, 0x17, 0xE0,
    0x2A, 0xDD, 0x93, 0x64, 0x0F, 0xF8, 0xB6, 0x41,
    0x60, 0x97, 0xD9, 0x2E, 0x45, 0xB2, 0xFC, 0x0B,
    0xBE, 0x49, 0x07, 0xF0, 0x9B, 0x6C, 0x22, 0xD5,
    0xF4, 0x03, 0x4D, 0xBA, 0xD1, 0x26, 0x68, 0x9F
};

#define CRC_INNER_LOOP(n, c, x) \
    (c) = ((c) >> 8) ^ crc##n##_table[((c) ^ (x)) & 0xff]

uint8
crc8(
    uint8 *pdata,  /* pointer to array of data to process */
    uint nbytes, /* number of input data bytes to process */
    uint8 crc      /* either CRC8_INIT_VALUE or previous return value */
)
{
    while (nbytes-- > 0)
        CRC_INNER_LOOP(8, crc, *pdata++);
    return crc;
}

/*******************************************************************************
 * crc16
 *
 * Computes a crc16 over the input data using the polynomial:
 *
 *       x^16 + x^12 +x^5 + 1
 *
 * The caller provides the initial value (either CRC16_INIT_VALUE
 * or the previous returned value) to allow for processing of 
 * discontiguous blocks of data.  When generating the CRC the
 * caller is responsible for complementing the final return value
 * and inserting it into the byte stream.  When checking, a final
 * return value of CRC16_GOOD_VALUE indicates a valid CRC.
 *
 * Reference: Dallas Semiconductor Application Note 27
 *   Williams, Ross N., "A Painless Guide to CRC Error Detection Algorithms", 
 *     ver 3, Aug 1993, ross@guest.adelaide.edu.au, Rocksoft Pty Ltd.,
 *     ftp://ftp.rocksoft.com/clients/rocksoft/papers/crc_v3.txt
 *
 ******************************************************************************/

static uint16 crc16_table[256] = {
    0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD, 0x6536, 0x74BF,
    0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7,
    0x1081, 0x0108, 0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E,
    0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64, 0xF9FF, 0xE876,
    0x2102, 0x308B, 0x0210, 0x1399, 0x6726, 0x76AF, 0x4434, 0x55BD,
    0xAD4A, 0xBCC3, 0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5,
    0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E, 0x54B5, 0x453C,
    0xBDCB, 0xAC42, 0x9ED9, 0x8F50, 0xFBEF, 0xEA66, 0xD8FD, 0xC974,
    0x4204, 0x538D, 0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB,
    0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1, 0xAB7A, 0xBAF3,
    0x5285, 0x430C, 0x7197, 0x601E, 0x14A1, 0x0528, 0x37B3, 0x263A,
    0xDECD, 0xCF44, 0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72,
    0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB, 0x0630, 0x17B9,
    0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5, 0xA96A, 0xB8E3, 0x8A78, 0x9BF1,
    0x7387, 0x620E, 0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738,
    0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862, 0x9AF9, 0x8B70,
    0x8408, 0x9581, 0xA71A, 0xB693, 0xC22C, 0xD3A5, 0xE13E, 0xF0B7,
    0x0840, 0x19C9, 0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF,
    0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324, 0xF1BF, 0xE036,
    0x18C1, 0x0948, 0x3BD3, 0x2A5A, 0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E,
    0xA50A, 0xB483, 0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5,
    0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF, 0x4C74, 0x5DFD,
    0xB58B, 0xA402, 0x9699, 0x8710, 0xF3AF, 0xE226, 0xD0BD, 0xC134,
    0x39C3, 0x284A, 0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C,
    0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1, 0xA33A, 0xB2B3,
    0x4A44, 0x5BCD, 0x6956, 0x78DF, 0x0C60, 0x1DE9, 0x2F72, 0x3EFB,
    0xD68D, 0xC704, 0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232,
    0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68, 0x3FF3, 0x2E7A,
    0xE70E, 0xF687, 0xC41C, 0xD595, 0xA12A, 0xB0A3, 0x8238, 0x93B1,
    0x6B46, 0x7ACF, 0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9,
    0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022, 0x92B9, 0x8330,
    0x7BC7, 0x6A4E, 0x58D5, 0x495C, 0x3DE3, 0x2C6A, 0x1EF1, 0x0F78
};

uint16
crc16(
    uint8 *pdata,  /* pointer to array of data to process */
    uint nbytes, /* number of input data bytes to process */
    uint16 crc     /* either CRC16_INIT_VALUE or previous return value */
)
{
    while (nbytes-- > 0)
        CRC_INNER_LOOP(16, crc, *pdata++);
    return crc;
}

/*******************************************************************************
 * crc32
 *
 * Computes a crc32 over the input data using the polynomial:
 *
 *       x^32+x^26+x^23+x^22+x^16+x^12+x^11+X^10+x^8+x^7+x^5+x^4+x^2+x+1
 *
 * The caller provides the initial value (either CRC32_INIT_VALUE
 * or the previous returned value) to allow for processing of 
 * discontiguous blocks of data.  When generating the CRC the
 * caller is responsible for complementing the final return value
 * and inserting it into the byte stream.  When checking, a final
 * return value of CRC32_GOOD_VALUE indicates a valid CRC.
 *
 * Reference: Dallas Semiconductor Application Note 27
 *   Williams, Ross N., "A Painless Guide to CRC Error Detection Algorithms", 
 *     ver 3, Aug 1993, ross@guest.adelaide.edu.au, Rocksoft Pty Ltd.,
 *     ftp://ftp.rocksoft.com/clients/rocksoft/papers/crc_v3.txt
 *
 ******************************************************************************/

static uint32 crc32_table[256] = {
    0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
    0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
    0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
    0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
    0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
    0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
    0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
    0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
    0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
    0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
    0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
    0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
    0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
    0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
    0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
    0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
    0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
    0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
    0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
    0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
    0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
    0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
    0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
    0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
    0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
    0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
    0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
    0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
    0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
    0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
    0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
    0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
    0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
    0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
    0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
    0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
    0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
    0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
    0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
    0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
    0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
    0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
    0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
    0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
    0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
    0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
    0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
    0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
    0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
    0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
    0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
    0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
    0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
    0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
    0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
    0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
    0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
    0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
    0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
    0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
    0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
    0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
    0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
    0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
};

uint32
crc32(
    uint8 *pdata,  /* pointer to array of data to process */
    uint nbytes, /* number of input data bytes to process */
    uint32 crc     /* either CRC32_INIT_VALUE or previous return value */
)
{
    while (nbytes-- > 0)
        CRC_INNER_LOOP(32, crc, *pdata++);
    return crc;
}