Hi Tobias,

Yes, it looks good.

Levente

On Wed, 21 Oct 2015, Tobias Pape wrote:

> Hi all
>
> I hope this version is an improvement over the last attempt :)
> Levente, is this way of using the Random generator useful?
> That is, Class-wide, guarded with a Semaphore and re-seeded at
> image startup?
>
> Best regards
> 	-Tobias
>
> On 21.10.2015, at 18:26, commits at source.squeak.org wrote:
>
>> Tobias Pape uploaded a new version of Network to project The Inbox:
>> http://source.squeak.org/inbox/Network-topa.166.mcz
>>
>> ==================== Summary ====================
>>
>> Name: Network-topa.166
>> Author: topa
>> Time: 21 October 2015, 8:26:14.656 pm
>> UUID: d6d9910f-fa67-4c69-9a89-030c81233e90
>> Ancestors: Network-topa.165
>>
>> UUIDGenerator
>> - Use new Random>>#nextBytes:into:startingAt: (needs Kernel-ul.960) for even more speed
>> - Fix UUIDGenerator class>>#initialize to correctly register at startup
>> - Do not reset default on startup but rather reseed TheRandom
>>
>> Timings improved:  '1,190,000 per second. 842 nanoseconds per run.' (0.25 times slower than primitive version)
>>
>> =============== Diff against Network-topa.165 ===============
>>
>> Item was changed:
>>  Object subclass: #UUIDGenerator
>> + 	instanceVariableNames: ''
>> - 	instanceVariableNames: 'bits'
>>  	classVariableNames: 'Default TheRandom TheSemaphore'
>>  	poolDictionaries: ''
>>  	category: 'Network-UUID'!
>>
>>  !UUIDGenerator commentStamp: 'topa 10/19/2015 23:23:19' prior: 0!
>>  I generate a pseudo-random UUID by asking Random for a 128 bit value.
>>
>>  See https://tools.ietf.org/html/rfc4122.html#section-4.4 for reference.!
>>
>> Item was changed:
>>  ----- Method: UUIDGenerator class>>default (in category 'instance creation') -----
>>  default
>> + 	^ Default ifNil: [Default := self new]
>> + !
>> - 	Default ifNil: [self generateDefault].
>> - 	^Default!
>>
>> Item was removed:
>> - ----- Method: UUIDGenerator class>>generateDefault (in category 'instance creation') -----
>> - generateDefault
>> - 	Default := self new!
>>
>> Item was changed:
>>  ----- Method: UUIDGenerator class>>initialize (in category 'class initialization') -----
>>  initialize
>>  	TheRandom := Random new.
>>  	TheSemaphore := Semaphore forMutualExclusion.
>> + 	Smalltalk addToStartUpList: self!
>> - 	Smalltalk addToStartUpList: self after: nil.!
>>
>> Item was added:
>> + ----- Method: UUIDGenerator class>>resetDefault (in category 'class initialization') -----
>> + resetDefault
>> + 	Default := nil.!
>>
>> Item was changed:
>>  ----- Method: UUIDGenerator class>>startUp (in category 'class initialization') -----
>>  startUp
>> + 	"Reseed the random"
>> + 	TheSemaphore critical: [TheRandom seed: nil].!
>> - 	Default := nil!
>>
>> Item was added:
>> + ----- Method: UUIDGenerator>>fillRandomly: (in category 'instance creation') -----
>> + fillRandomly: aUUID
>> +
>> + 	TheSemaphore critical: [
>> + 		TheRandom nextBytes: 16 "128 bit" into: aUUID startingAt: 1].!
>>
>> Item was changed:
>>  ----- Method: UUIDGenerator>>generateBytes:forVersion: (in category 'instance creation') -----
>> + generateBytes: aUUID forVersion: aVersion
>> + 	| versionID fixedValue |
>> +
>> + 	aVersion = 4 ifFalse: [^ self error: 'Unsupported version'].
>> +
>> + 	self fillRandomly: aUUID.
>> + 	versionID := ((aUUID at: 7) bitAnd: 16r0F) bitOr: 16r40. "Version 4"
>> + 	fixedValue := ((aUUID at: 9) bitAnd: 16r3F) bitOr: 16r80. "Fixed 8..b value"
>> + 	aUUID
>> + 		at: 7 put: versionID;
>> + 		at: 9 put: fixedValue.!
>> - generateBytes: aPlaceHolder forVersion: aVersion
>> - 	aVersion = 4 ifTrue: [self generateFieldsVersion4]
>> - 		ifFalse: [self error: 'Unsupported version'].
>> - 	self placeFields: aPlaceHolder.!
>>
>> Item was removed:
>> - ----- Method: UUIDGenerator>>generateFieldsVersion4 (in category 'instance creation') -----
>> - generateFieldsVersion4
>> -
>> - 	TheSemaphore critical: [
>> - 		bits := 16rffffffffffffffffffffffffffffffff atRandom: TheRandom. "128 bit"].!
>>
>> Item was removed:
>> - ----- Method: UUIDGenerator>>placeFields: (in category 'instance creation') -----
>> - placeFields: aByteArray
>> -
>> - 	| version fixed |
>> - 	bits isLarge
>> - 		ifTrue: [	aByteArray replaceFrom: 1 to: bits size with: bits]
>> - 		ifFalse: [aByteArray unsignedLongAt: 1 put: bits bigEndian: false].
>> -
>> - 	version := ((aByteArray at: 7) bitAnd: 16r0F) bitOr: 16r40. "Version 4"
>> - 	fixed := ((aByteArray at: 9) bitAnd: 16r3F) bitOr: 16r80. "Fixed 8..b value"
>> - 	aByteArray
>> - 		at: 7 put: version;
>> - 		at: 9 put: fixed.!
>>
>>
>
>
>