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Initial checkin. Standalone program used to generate crc table needed

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for calculating udf crc checksums.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@5558 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Tyler Dauwalder 2003-12-04 07:59:49 +00:00
parent b9a05f7f4c
commit f546c8aff5
1 changed files with 53 additions and 0 deletions
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53
src/add-ons/kernel/file_systems/udf/crc_table.cpp Normal file
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//----------------------------------------------------------------------
// This software is part of the OpenBeOS distribution and is covered
// by the OpenBeOS license.
//
// Copyright (c) 2003 Tyler Dauwalder, tyler@dauwalder.net
//---------------------------------------------------------------------
/*! \file crc_table.cpp
Standalone program to generate the CRC table used for calculating
UDF tag id CRC values.
This code based off of crc code in UDF-2.50 specs, as permitted.
See UDF-2.50 6.5 for more information.
*/
#include <stdio.h>
int
main(int argc, char *argv[]) {
ulong crc, poly;
if (argc != 2) {
fprintf(stderr, "USAGE: crc_table <octal polynomial=010041 for UDF>\n");
return 0;
}
sscanf(argv[1], "%lo", &poly);
if (poly & 0xffff0000) {
fprintf(stderr, "ERROR: polynomial is too large, sucka.\n");
return 0;
}
printf("//! CRC 0%o table, as generated by crc_table.cpp\n", poly);
printf("static uint16 crc_table[256] = { \n");
for (int n = 0; n < 256; n++) {
if (n%8 == 0)
printf(" ");
crc = n << 8;
for (int i = 0; i < 8; i++) {
if (crc & 0x8000)
crc = (crc << 1) ^ poly;
else
crc <<= 1;
crc &= 0xffff;
}
printf("0x%04x%s ", crc, (n != 255 ? "," : ""));
if (n%8 == 7)
printf("\n");
}
printf("};\n");
return 0;
}