#include "crc32.h"

#if 0
#define POLYNOMIAL  0xEDB88320
static uint32_t crc32_table[256];

void make_table()
{
    int i, j;
    for (i = 0 ; i < 256 ; i++)
        for (j = 0, crc32_table[i] = i ; j < 8 ; j++)
            crc32_table[i] = (crc32_table[i]>>1)^((crc32_table[i]&1)?POLYNOMIAL:0) ;
}
#else
/* CRC-32 Lookup Table */
static uint32_t crc32_table[256] =
{
 /*   0 -- */ 0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 
 /*   4 -- */ 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3, 
 /*   8 -- */ 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 
 /*  12 -- */ 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, 
 /*  16 -- */ 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 
 /*  20 -- */ 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 
 /*  24 -- */ 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 
 /*  28 -- */ 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, 
 /*  32 -- */ 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 
 /*  36 -- */ 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 
 /*  40 -- */ 0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 
 /*  44 -- */ 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 
 /*  48 -- */ 0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 
 /*  52 -- */ 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F, 
 /*  56 -- */ 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 
 /*  60 -- */ 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 
 /*  64 -- */ 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 
 /*  68 -- */ 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433, 
 /*  72 -- */ 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 
 /*  76 -- */ 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01, 
 /*  80 -- */ 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 
 /*  84 -- */ 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 
 /*  88 -- */ 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 
 /*  92 -- */ 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 
 /*  96 -- */ 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 
 /* 100 -- */ 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 
 /* 104 -- */ 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 
 /* 108 -- */ 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 
 /* 112 -- */ 0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 
 /* 116 -- */ 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F, 
 /* 120 -- */ 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 
 /* 124 -- */ 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 
 /* 128 -- */ 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 
 /* 132 -- */ 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, 
 /* 136 -- */ 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 
 /* 140 -- */ 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 
 /* 144 -- */ 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 
 /* 148 -- */ 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7, 
 /* 152 -- */ 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 
 /* 156 -- */ 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 
 /* 160 -- */ 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 
 /* 164 -- */ 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B, 
 /* 168 -- */ 0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 
 /* 172 -- */ 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79, 
 /* 176 -- */ 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 
 /* 180 -- */ 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 
 /* 184 -- */ 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 
 /* 188 -- */ 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D, 
 /* 192 -- */ 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 
 /* 196 -- */ 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713, 
 /* 200 -- */ 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 
 /* 204 -- */ 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 
 /* 208 -- */ 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 
 /* 212 -- */ 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777, 
 /* 216 -- */ 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 
 /* 220 -- */ 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 
 /* 224 -- */ 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 
 /* 228 -- */ 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 
 /* 232 -- */ 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 
 /* 236 -- */ 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9, 
 /* 240 -- */ 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 
 /* 244 -- */ 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF, 
 /* 248 -- */ 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 
 /* 252 -- */ 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
};
#endif

uint32_t calc_crc32(uint32_t crc, char *buff, int len)
{
    //if (!have_table) make_table();
    int i;
    crc = ~crc;
    for (i = 0; i < len; i++)
        crc = (crc >> 8) ^ crc32_table[(crc ^ buff[i]) & 0xff];
    return ~crc;
}