/*
 * This is an implementation of CRC32. See ISO 3309 and ITU-T V.42 
 * for a formal specification
 *
 * This file is partly taken from Crypto++ library (http://www.cryptopp.com)
 * and http://www.di-mgt.com.au/crypto.html#CRC.
 *
 * Since the original version of the code is put in public domain,
 * this file is put on public domain as well.
 */
#include <pjlib-util/crc32.h>


#define CRC32_NEGL  0xffffffffL

#if defined(PJ_CRC32_HAS_TABLES) && PJ_CRC32_HAS_TABLES!=0
// crc.cpp - written and placed in the public domain by Wei Dai

/* Table of CRC-32's of all single byte values (made by makecrc.c) */
#if defined(PJ_IS_LITTLE_ENDIAN) && PJ_IS_LITTLE_ENDIAN != 0

#define CRC32_INDEX(c)      (c & 0xff)
#define CRC32_SHIFTED(c)    (c >> 8)
#define CRC32_SWAP(c)       (c)

static const pj_uint32_t crc_tab[] = {
    0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
    0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
    0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
    0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
    0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
    0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
    0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
    0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
    0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
    0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
    0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
    0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
    0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
    0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
    0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
    0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
    0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
    0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
    0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
    0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
    0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
    0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
    0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
    0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
    0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
    0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
    0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
    0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
    0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
    0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
    0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
    0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
    0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
    0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
    0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
    0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
    0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
    0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
    0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
    0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
    0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
    0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
    0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
    0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
    0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
    0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
    0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
    0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
    0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
    0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
    0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
    0x2d02ef8dL
};


#elif defined(PJ_IS_BIG_ENDIAN) && PJ_IS_BIG_ENDIAN != 0
#define CRC32_INDEX(c)      (c >> 24)
#define CRC32_SHIFTED(c)    (c << 8)
#define CRC32_SWAP(c)       ((((c) & 0xff000000) >> 24) | \
                             (((c) & 0x00ff0000) >>  8) | \
                             (((c) & 0x0000ff00) <<  8) | \
                             (((c) & 0x000000ff) << 24))

static const pj_uint32_t crc_tab[] = {
    0x00000000L, 0x96300777L, 0x2c610eeeL, 0xba510999L, 0x19c46d07L,
    0x8ff46a70L, 0x35a563e9L, 0xa395649eL, 0x3288db0eL, 0xa4b8dc79L,
    0x1ee9d5e0L, 0x88d9d297L, 0x2b4cb609L, 0xbd7cb17eL, 0x072db8e7L,
    0x911dbf90L, 0x6410b71dL, 0xf220b06aL, 0x4871b9f3L, 0xde41be84L,
    0x7dd4da1aL, 0xebe4dd6dL, 0x51b5d4f4L, 0xc785d383L, 0x56986c13L,
    0xc0a86b64L, 0x7af962fdL, 0xecc9658aL, 0x4f5c0114L, 0xd96c0663L,
    0x633d0ffaL, 0xf50d088dL, 0xc8206e3bL, 0x5e10694cL, 0xe44160d5L,
    0x727167a2L, 0xd1e4033cL, 0x47d4044bL, 0xfd850dd2L, 0x6bb50aa5L,
    0xfaa8b535L, 0x6c98b242L, 0xd6c9bbdbL, 0x40f9bcacL, 0xe36cd832L,
    0x755cdf45L, 0xcf0dd6dcL, 0x593dd1abL, 0xac30d926L, 0x3a00de51L,
    0x8051d7c8L, 0x1661d0bfL, 0xb5f4b421L, 0x23c4b356L, 0x9995bacfL,
    0x0fa5bdb8L, 0x9eb80228L, 0x0888055fL, 0xb2d90cc6L, 0x24e90bb1L,
    0x877c6f2fL, 0x114c6858L, 0xab1d61c1L, 0x3d2d66b6L, 0x9041dc76L,
    0x0671db01L, 0xbc20d298L, 0x2a10d5efL, 0x8985b171L, 0x1fb5b606L,
    0xa5e4bf9fL, 0x33d4b8e8L, 0xa2c90778L, 0x34f9000fL, 0x8ea80996L,
    0x18980ee1L, 0xbb0d6a7fL, 0x2d3d6d08L, 0x976c6491L, 0x015c63e6L,
    0xf4516b6bL, 0x62616c1cL, 0xd8306585L, 0x4e0062f2L, 0xed95066cL,
    0x7ba5011bL, 0xc1f40882L, 0x57c40ff5L, 0xc6d9b065L, 0x50e9b712L,
    0xeab8be8bL, 0x7c88b9fcL, 0xdf1ddd62L, 0x492dda15L, 0xf37cd38cL,
    0x654cd4fbL, 0x5861b24dL, 0xce51b53aL, 0x7400bca3L, 0xe230bbd4L,
    0x41a5df4aL, 0xd795d83dL, 0x6dc4d1a4L, 0xfbf4d6d3L, 0x6ae96943L,
    0xfcd96e34L, 0x468867adL, 0xd0b860daL, 0x732d0444L, 0xe51d0333L,
    0x5f4c0aaaL, 0xc97c0dddL, 0x3c710550L, 0xaa410227L, 0x10100bbeL,
    0x86200cc9L, 0x25b56857L, 0xb3856f20L, 0x09d466b9L, 0x9fe461ceL,
    0x0ef9de5eL, 0x98c9d929L, 0x2298d0b0L, 0xb4a8d7c7L, 0x173db359L,
    0x810db42eL, 0x3b5cbdb7L, 0xad6cbac0L, 0x2083b8edL, 0xb6b3bf9aL,
    0x0ce2b603L, 0x9ad2b174L, 0x3947d5eaL, 0xaf77d29dL, 0x1526db04L,
    0x8316dc73L, 0x120b63e3L, 0x843b6494L, 0x3e6a6d0dL, 0xa85a6a7aL,
    0x0bcf0ee4L, 0x9dff0993L, 0x27ae000aL, 0xb19e077dL, 0x44930ff0L,
    0xd2a30887L, 0x68f2011eL, 0xfec20669L, 0x5d5762f7L, 0xcb676580L,
    0x71366c19L, 0xe7066b6eL, 0x761bd4feL, 0xe02bd389L, 0x5a7ada10L,
    0xcc4add67L, 0x6fdfb9f9L, 0xf9efbe8eL, 0x43beb717L, 0xd58eb060L,
    0xe8a3d6d6L, 0x7e93d1a1L, 0xc4c2d838L, 0x52f2df4fL, 0xf167bbd1L,
    0x6757bca6L, 0xdd06b53fL, 0x4b36b248L, 0xda2b0dd8L, 0x4c1b0aafL,
    0xf64a0336L, 0x607a0441L, 0xc3ef60dfL, 0x55df67a8L, 0xef8e6e31L,
    0x79be6946L, 0x8cb361cbL, 0x1a8366bcL, 0xa0d26f25L, 0x36e26852L,
    0x95770cccL, 0x03470bbbL, 0xb9160222L, 0x2f260555L, 0xbe3bbac5L,
    0x280bbdb2L, 0x925ab42bL, 0x046ab35cL, 0xa7ffd7c2L, 0x31cfd0b5L,
    0x8b9ed92cL, 0x1daede5bL, 0xb0c2649bL, 0x26f263ecL, 0x9ca36a75L,
    0x0a936d02L, 0xa906099cL, 0x3f360eebL, 0x85670772L, 0x13570005L,
    0x824abf95L, 0x147ab8e2L, 0xae2bb17bL, 0x381bb60cL, 0x9b8ed292L,
    0x0dbed5e5L, 0xb7efdc7cL, 0x21dfdb0bL, 0xd4d2d386L, 0x42e2d4f1L,
    0xf8b3dd68L, 0x6e83da1fL, 0xcd16be81L, 0x5b26b9f6L, 0xe177b06fL,
    0x7747b718L, 0xe65a0888L, 0x706a0fffL, 0xca3b0666L, 0x5c0b0111L,
    0xff9e658fL, 0x69ae62f8L, 0xd3ff6b61L, 0x45cf6c16L, 0x78e20aa0L,
    0xeed20dd7L, 0x5483044eL, 0xc2b30339L, 0x612667a7L, 0xf71660d0L,
    0x4d476949L, 0xdb776e3eL, 0x4a6ad1aeL, 0xdc5ad6d9L, 0x660bdf40L,
    0xf03bd837L, 0x53aebca9L, 0xc59ebbdeL, 0x7fcfb247L, 0xe9ffb530L,
    0x1cf2bdbdL, 0x8ac2bacaL, 0x3093b353L, 0xa6a3b424L, 0x0536d0baL,
    0x9306d7cdL, 0x2957de54L, 0xbf67d923L, 0x2e7a66b3L, 0xb84a61c4L,
    0x021b685dL, 0x942b6f2aL, 0x37be0bb4L, 0xa18e0cc3L, 0x1bdf055aL,
    0x8def022dL
};

#else
#   error "Endianness not defined"
#endif


PJ_DEF(void) pj_crc32_init(pj_crc32_context *ctx)
{
    ctx->crc_state = 0;
}

PJ_DEF(pj_uint32_t) pj_crc32_update(pj_crc32_context *ctx, 
                                    const pj_uint8_t *data,
                                    pj_size_t nbytes)
{
    pj_uint32_t crc = ctx->crc_state ^ CRC32_NEGL;

    for( ; (((unsigned long)(pj_ssize_t)data) & 0x03) && nbytes > 0; --nbytes) {
        crc = crc_tab[CRC32_INDEX(crc) ^ *data++] ^ CRC32_SHIFTED(crc);
    }

    while (nbytes >= 4) {
        crc ^= *(const pj_uint32_t *)data;
        crc = crc_tab[CRC32_INDEX(crc)] ^ CRC32_SHIFTED(crc);
        crc = crc_tab[CRC32_INDEX(crc)] ^ CRC32_SHIFTED(crc);
        crc = crc_tab[CRC32_INDEX(crc)] ^ CRC32_SHIFTED(crc);
        crc = crc_tab[CRC32_INDEX(crc)] ^ CRC32_SHIFTED(crc);
        nbytes -= 4;
        data += 4;
    }

    while (nbytes--) {
        crc = crc_tab[CRC32_INDEX(crc) ^ *data++] ^ CRC32_SHIFTED(crc);
    }

    ctx->crc_state = crc ^ CRC32_NEGL;

    return ctx->crc_state;
}

PJ_DEF(pj_uint32_t) pj_crc32_final(pj_crc32_context *ctx)
{
    return CRC32_SWAP(ctx->crc_state);
}


#else

PJ_DEF(void) pj_crc32_init(pj_crc32_context *ctx)
{
    ctx->crc_state = CRC32_NEGL;
}


PJ_DEF(pj_uint32_t) pj_crc32_update(pj_crc32_context *ctx, 
                                    const pj_uint8_t *octets,
                                    pj_size_t len)

{
    pj_uint32_t crc = ctx->crc_state;
    
    while (len--) {
        pj_uint32_t temp;
        int j;

        temp = (pj_uint32_t)((crc & 0xFF) ^ *octets++);
        for (j = 0; j < 8; j++)
        {
            if (temp & 0x1)
                temp = (temp >> 1) ^ 0xEDB88320;
            else
                temp >>= 1;
        }
        crc = (crc >> 8) ^ temp;
    }
    ctx->crc_state = crc;

    return crc ^ CRC32_NEGL;
}

PJ_DEF(pj_uint32_t) pj_crc32_final(pj_crc32_context *ctx)
{
    ctx->crc_state ^= CRC32_NEGL;
    return ctx->crc_state;
}

#endif


PJ_DEF(pj_uint32_t) pj_crc32_calc( const pj_uint8_t *data,
                                   pj_size_t nbytes)
{
    pj_crc32_context ctx;

    pj_crc32_init(&ctx);
    pj_crc32_update(&ctx, data, nbytes);
    return pj_crc32_final(&ctx);
}

