Pillow/libImaging/Crc32.c

/*
 * The Python Imaging Library
 * $Id$
 *
 * calculate ISO 3307 checksum
 *
 * history:
 *	96-12-10 fl:	Created (based on example in the PNG spec)
 *
 * Copyright (c) Fredrik Lundh 1996.
 * Copyright (c) Secret Labs AB 1997.
 *
 * See the README file for information on usage and redistribution.
 */


#include "Imaging.h"


/* Precalculated CRC values (created by makecrctable.py) */

static UINT32 crc32table[] = { 0x0, 0x77073096L, 0xEE0E612CL,
0x990951BAL, 0x76DC419L, 0x706AF48FL, 0xE963A535L, 0x9E6495A3L,
0xEDB8832L, 0x79DCB8A4L, 0xE0D5E91EL, 0x97D2D988L, 0x9B64C2BL,
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, 0x1DB7106L, 0x98D220BCL, 0xEFD5102AL,
0x71B18589L, 0x6B6B51FL, 0x9FBFE4A5L, 0xE8B8D433L, 0x7807C9A2L,
0xF00F934L, 0x9609A88EL, 0xE10E9818L, 0x7F6A0DBBL, 0x86D3D2DL,
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, 0x3B6E20CL, 0x74B1D29AL, 0xEAD54739L,
0x9DD277AFL, 0x4DB2615L, 0x73DC1683L, 0xE3630B12L, 0x94643B84L,
0xD6D6A3EL, 0x7A6A5AA8L, 0xE40ECF0BL, 0x9309FF9DL, 0xA00AE27L,
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, 0x26D930AL, 0x9C0906A9L, 0xEB0E363FL,
0x72076785L, 0x5005713L, 0x95BF4A82L, 0xE2B87A14L, 0x7BB12BAEL,
0xCB61B38L, 0x92D28E9BL, 0xE5D5BE0DL, 0x7CDCEFB7L, 0xBDBDF21L,
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 };


UINT32
ImagingCRC32(UINT32 crc, UINT8* buffer, int bytes)
{
    int i;

    crc ^= 0xFFFFFFFFL;

    for (i = 0; i < bytes; i++)
	crc = crc32table[(UINT8) crc ^ buffer[i]] ^ (crc >> 8);

    return crc ^ 0xFFFFFFFFL;
}