-
Notifications
You must be signed in to change notification settings - Fork 0
/
adler32.sh
45 lines (40 loc) · 1.24 KB
/
adler32.sh
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
#
# Copyright (c) 2018 Tristan Le Guern <tleguern@bouledef.eu>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
LIBNAME="libhash.sh"
LIBVERSION="1.0"
#
# ord() converts the given ASCII char to a decimal value
#
ord() {
printf "%d" "'$1"
}
adler32() {
_value="$*"
_s1=1
_s2=0
# Step 1. Process message
_us="$(printf "\037")"
OLDIFS="$IFS"
IFS="$_us"
for _i in $(printf "$_value" | sed "s/./&$_us/g"); do
_b=$(ord $_i)
_s1=$(( (_s1 + _b) % 65521 ))
_s2=$(( (_s2 + _s1) % 65521 ))
done
# Step 2. Output
printf "%08x\n" $(( (_s2 << 16) + _s1))
unset _value _s1 _s2 _i _us _b
}