Last change
on this file since 1426 was 821, checked in by Bruno Cornec, 18 years ago |
Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)
|
File size:
1.0 KB
|
Rev | Line | |
---|
[821] | 1 | /* vi: set sw=4 ts=4: */
|
---|
| 2 | /*
|
---|
| 3 | * CRC32 table fill function
|
---|
| 4 | * Copyright (C) 2006 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
|
---|
| 5 | * (I can't really claim much credit however, as the algorithm is
|
---|
| 6 | * very well-known)
|
---|
| 7 | *
|
---|
| 8 | * The following function creates a CRC32 table depending on whether
|
---|
| 9 | * a big-endian (0x04c11db7) or little-endian (0xedb88320) CRC32 is
|
---|
| 10 | * required. Admittedly, there are other CRC32 polynomials floating
|
---|
| 11 | * around, but Busybox doesn't use them.
|
---|
| 12 | *
|
---|
| 13 | * endian = 1: big-endian
|
---|
| 14 | * endian = 0: little-endian
|
---|
| 15 | */
|
---|
| 16 |
|
---|
| 17 | #include <stdio.h>
|
---|
| 18 | #include <stdlib.h>
|
---|
| 19 | #include "libbb.h"
|
---|
| 20 |
|
---|
| 21 | uint32_t *bb_crc32_filltable (int endian) {
|
---|
| 22 |
|
---|
| 23 | uint32_t *crc_table = xmalloc(256 * sizeof(uint32_t));
|
---|
| 24 | uint32_t polynomial = endian ? 0x04c11db7 : 0xedb88320;
|
---|
| 25 | uint32_t c;
|
---|
| 26 | int i, j;
|
---|
| 27 |
|
---|
| 28 | for (i = 0; i < 256; i++) {
|
---|
| 29 | c = endian ? (i << 24) : i;
|
---|
| 30 | for (j = 8; j; j--) {
|
---|
| 31 | if (endian)
|
---|
| 32 | c = (c&0x80000000) ? ((c << 1) ^ polynomial) : (c << 1);
|
---|
| 33 | else
|
---|
| 34 | c = (c&1) ? ((c >> 1) ^ polynomial) : (c >> 1);
|
---|
| 35 | }
|
---|
| 36 | *crc_table++ = c;
|
---|
| 37 | }
|
---|
| 38 |
|
---|
| 39 | return crc_table - 256;
|
---|
| 40 | }
|
---|
Note:
See
TracBrowser
for help on using the repository browser.