examples/Stdlib/GUIApp/CRC.C

00001 // Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
00002 // All rights reserved.
00003 // This component and the accompanying materials are made available
00004 // under the terms of "Eclipse Public License v1.0"
00005 // which accompanies this distribution, and is available
00006 // at the URL "http://www.eclipse.org/legal/epl-v10.html".
00007 //
00008 // Initial Contributors:
00009 // Nokia Corporation - initial contribution.
00010 //
00011 // Contributors:
00012 //
00013 // Description:
00014 //
00015 
00016 /*#ifndef lint
00017 const static char sccsid[] = "@(#)crc.c 8.1 (Berkeley) 6/17/93";
00018 #endif*/
00019 // not lint 
00020 
00021 #include <unistd.h>
00022 
00023 const static u_long crctab[] = {
00024         0x0,
00025         0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
00026         0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
00027         0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
00028         0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac,
00029         0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f,
00030         0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
00031         0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
00032         0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58,
00033         0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033,
00034         0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe,
00035         0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
00036         0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4,
00037         0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
00038         0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5,
00039         0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
00040         0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07,
00041         0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c,
00042         0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
00043         0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
00044         0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b,
00045         0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698,
00046         0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d,
00047         0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
00048         0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f,
00049         0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
00050         0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
00051         0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
00052         0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a,
00053         0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629,
00054         0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c,
00055         0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
00056         0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e,
00057         0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65,
00058         0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8,
00059         0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
00060         0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2,
00061         0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
00062         0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74,
00063         0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
00064         0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21,
00065         0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a,
00066         0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087,
00067         0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
00068         0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d,
00069         0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce,
00070         0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb,
00071         0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
00072         0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09,
00073         0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
00074         0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf,
00075         0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
00076 };
00077 
00078 /*
00079  * Compute a POSIX 1003.2 checksum.  This routine has been broken out so that
00080  * other programs can use it.  It takes a file descriptor to read from and
00081  * locations to store the crc and the number of bytes read.  It returns 0 on
00082  * success and 1 on failure.  Errno is set on failure.
00083  */
00084 
00085 
00086 EXPORT_C int crc(register int fd, u_long *cval, u_long *clen)
00087 {
00088         u_long crc_total = (u_long)~0;  /* The crc over a number of files*/
00089         register u_char *p;
00090         register int nr;
00091         register u_long crc, len;
00092 //      u_char buf[16 * 1024]; // too large for stack
00093         u_char buf[3 * 1024];
00094 
00095 #define COMPUTE(var, ch)        (var) = (var) << 8 ^ crctab[(var) >> 24 ^ (ch)]
00096 
00097         crc = len = 0;
00098         crc_total = ~crc_total;
00099         while ((nr = read(fd, (char*)buf, sizeof(buf))) > 0)
00100                 for (len += nr, p = buf; nr--; ++p) {
00101                         COMPUTE(crc, *p);
00102                         COMPUTE(crc_total, *p);
00103                 }
00104         if (nr < 0)
00105                 return (1);
00106 
00107         *clen = len;
00108 
00109         /* Include the length of the file. */
00110         for (; len != 0; len >>= 8) {
00111                 COMPUTE(crc, len & 0xff);
00112                 COMPUTE(crc_total, len & 0xff);
00113         }
00114 
00115         *cval = ~crc;
00116         crc_total = ~crc_total;
00117         return (0);
00118 }
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Copyright ©2010 Nokia Corporation and/or its subsidiary(-ies).
All rights reserved. Unless otherwise stated, these materials are provided under the terms of the Eclipse Public License v1.0.