This is checksum.c in view mode; [Download] [Up]
/*
From alfred!nevets!ssd@osceola.cs.ucf.edu Sun Dec 13 14:25:07 1992
Return-Path: <alfred!nevets!ssd@osceola.cs.ucf.edu>
Received: from osceola.cs.ucf.edu by tartarus.uwa.edu.au (5.65c/SMI-4.1)
id AA01410; Sun, 13 Dec 1992 14:24:59 +0800
Received: from alfred.UUCP by osceola.cs.ucf.edu (4.1/1.34)
id AA17217; Sun, 13 Dec 92 01:23:58 EST
Received: by alfred.oau.org (/\==/\ Smail3.1.28.1 #28.1)
id <m0n0mW0-00009iC@alfred.oau.org>; Sun, 13 Dec 92 01:09 EST
Received: by nevets.oau.org (Smail3.1.28.1 #2)
id m0n0mJs-0000OhC; Sun, 13 Dec 92 00:56 EST
Message-Id: <m0n0mJs-0000OhC@nevets.oau.org>
From: ssd@nevets.oau.org (Steven S. Dick)
Date: Sun, 13 Dec 1992 00:56:47 EST
X-Mailer: Mail User's Shell (7.2.4 2/2/92)
To: oreillym
Subject: term checksum stuff
Status: OR
I've got some old code to do checksums...
Would you like me to just send you this code as I have it?
If I get around to it (I've got 4 other projects going), I am thinking
of possibly modifying tupload to use this to verify the files when it
finishes...especially to verify that it is identical on both ends before
it starts appending.
Also, I've had problems with the checksum stuff.
Occasionaly, I get a really bad blast of line noise that gets by
the checksums, and then the compression routines core dump on bad data.
It would be nice to have better error checking in this respect.
The checksum routines I have are table driven...
[heck, the thing is 3k, I'll just include it here.]
Steve
-----------------------
crc - list length and checksum Author: Johan W. Stevenson */
/* crctab calculated by Mark G. Mendel, Network Systems Corporation */
static unsigned short crctab[256] = {
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
};
/*
* updcrc macro derived from article Copyright (C) 1986 Stephen Satchell.
* NOTE: First argument must be in range 0 to 255.
* Second argument is referenced twice.
*
* Programmers may incorporate any or all code into their programs,
* giving proper credit within the source. Publication of the
* source routines is permitted so long as proper credit is given
* to Stephen Satchell, Satchell Evaluations and Chuck Forsberg,
* Omen Technology.
*/
#define updcrc(cp, crc) ( crctab[((crc >> 8) & 255)] ^ (crc << 8) ^ cp)
unsigned short check_sum(unsigned char *d, int len, int mask)
{
unsigned short crc = 0;
while (len-->0)
crc = updcrc(((*d++) & mask), crc);
return crc;
}
unsigned short update_crc(unsigned short old, unsigned char c)
{
return updcrc(c, old);
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.