mirror of
https://github.com/sheumann/hush.git
synced 2024-07-07 10:28:56 +00:00
d921b2ecc0
things like xasprintf() into xfuncs.c, remove xprint_file_by_name() (it only had one user), clean up lots of #includes... General cleanup pass. What I've been doing for the last couple days. And it conflicts! I've removed httpd.c from this checkin due to somebody else touching that file. It builds for me. I have to catch a bus. (Now you know why I'm looking forward to Mercurial.)
40 lines
1000 B
C
40 lines
1000 B
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* CRC32 table fill function
|
|
* Copyright (C) 2006 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
|
|
* (I can't really claim much credit however, as the algorithm is
|
|
* very well-known)
|
|
*
|
|
* The following function creates a CRC32 table depending on whether
|
|
* a big-endian (0x04c11db7) or little-endian (0xedb88320) CRC32 is
|
|
* required. Admittedly, there are other CRC32 polynomials floating
|
|
* around, but Busybox doesn't use them.
|
|
*
|
|
* endian = 1: big-endian
|
|
* endian = 0: little-endian
|
|
*/
|
|
|
|
#include "libbb.h"
|
|
|
|
uint32_t *crc32_filltable(int endian)
|
|
{
|
|
|
|
uint32_t *crc_table = xmalloc(256 * sizeof(uint32_t));
|
|
uint32_t polynomial = endian ? 0x04c11db7 : 0xedb88320;
|
|
uint32_t c;
|
|
int i, j;
|
|
|
|
for (i = 0; i < 256; i++) {
|
|
c = endian ? (i << 24) : i;
|
|
for (j = 8; j; j--) {
|
|
if (endian)
|
|
c = (c&0x80000000) ? ((c << 1) ^ polynomial) : (c << 1);
|
|
else
|
|
c = (c&1) ? ((c >> 1) ^ polynomial) : (c >> 1);
|
|
}
|
|
*crc_table++ = c;
|
|
}
|
|
|
|
return crc_table - 256;
|
|
}
|