in squeak trunk
Can some of you double check this change from squeaktrunk Name: Files-jcg.27
In squeak
checkSum: aString
"Construct a checksum of the string. A three byte number represented
as Base64 characters."
| sum shift bytes |
sum := aString size.
shift := 0.
aString do: [:char |
(shift := shift + 7) > 16 ifTrue: [shift := shift - 17].
"shift by 7 to keep a change of adjacent chars from
xoring to same value"
sum := sum bitXor: (char asInteger bitShift: shift)
].
bytes := ByteArray new: 3.
sum := sum + 16r10000000000.
1 to: 3 do: [:ind | bytes at: ind put: (sum digitAt: ind)].
^bytes base64Encoded
In pharo
checkSum: aString
"Construct a checksum of the string. A three byte number represented
as Base64 characters."
| sum shift bytes ss bb |
sum := aString size.
shift := 0.
aString do: [:char |
(shift := shift + 7) > 16 ifTrue: [shift := shift - 17].
"shift by 7 to keep a change of adjacent chars from xoring to
same value"
sum := sum bitXor: (char asInteger bitShift: shift)].
bytes := ByteArray new: 3.
sum := sum + 16r10000000000.
1 to: 3 do: [:ind | bytes at: ind put: (sum digitAt: ind)].
ss := ReadWriteStream on: (ByteArray new: 3).
ss nextPutAll: bytes.
bb := Base64MimeConverter mimeEncode: ss.
^ bb contents
Thanks
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