Hi all,

On 20.10.2015, at 07:53, Levente Uzonyi <leves at elte.hu> wrote:

> Hi Tobias,
> 
> TheRandom should be re-seeded on startup, so that images don't generate the same UUIDs.
> Integer >> atRandom: creates a random number between 1 and the receiver,
> so 16rffffffffffffffffffffffffffffffff atRandom: TheRandom won't create
> all possible 128-bit values. It's also a bit slow to create an intermediate Integer objects for this, so I suggest you should use Random 
>>> #nextBytes:into:startingAt: instead to fill the UUID object with random
> bytes.


I thought about going back to ThreadSafeRandom, it seems more fit.

About the speed, I was actually quite happy with it ;)
But I see your point.

Best regards
	-Tobias

> 
> Levente
> 
> On Mon, 19 Oct 2015, Tobias Pape wrote:
> 
>> Hi all
>> 
>> Don't hold back your comments.
>> I'd like to put this into trunk and enable people not to have to install
>> libuuid1:i386 in their shiny new 64-bit Linux environment ;)
>> 
>> Best regards
>> 	-Tobias
>> 
>> On 19.10.2015, at 21:28, 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.165.mcz
>>> 
>>> ==================== Summary ====================
>>> 
>>> Name: Network-topa.165
>>> Author: topa
>>> Time: 19 October 2015, 11:28:20.052 pm
>>> UUID: b4b1febc-df00-4213-b76f-c007b06bb2e2
>>> Ancestors: Network-ul.164
>>> 
>>> Simplify and speed up non-primitive UUID generation (hat-tip to Martin McClure <martin.mcclure at gemtalksystems.com>)
>>> 
>>> Instead of generating all parts of the UUID separately, we generate
>>> a single, 128-bit number and modify it slightly to match the UUID definition.
>>> This complies with RFC 4122, Sec. 4.4.
>>> 
>>> This approach is 2500 times faster than the old method and only about 3 times
>>> slower than the primitive. Hence, we disable the primitive and no longer need
>>> to rely on the UUIDPlugin to be present.
>>> 
>>> Informational: The Timings:
>>> 
>>> {
>>> 'Pure allocation' -> [UUID basicNew: 16] bench.
>>> 'Primitive + alloc' -> [(UUID basicNew: 16) primMakeUUID] bench.
>>> 'Old +  alloc' -> [|u| u := (UUID basicNew: 16). UUIDGeneratorOld new generateBytes: u forVersion: 4] bench.
>>> 'New + alloc' -> [|u| u := (UUID basicNew: 16). UUIDGeneratorNew new generateBytes: u forVersion: 4] bench.
>>> }.
>>> "{
>>> 'Pure allocation'->'56,500,000 per second. 17.7 nanoseconds per run.' .
>>> 'Primitive + alloc'->'1,510,000 per second. 663 nanoseconds per run.' .
>>> 'Old +  alloc'->'202 per second. 4.95 milliseconds per run.' .
>>> 'New + alloc'->'519,000 per second. 1.93 microseconds per run.'
>>> }."
>>> 
>>> =============== Diff against Network-ul.164 ===============
>>> 
>>> Item was changed:
>>> ----- Method: String>>asAlphaNumeric:extraChars:mergeUID: (in category '*network-uuid') -----
>>> asAlphaNumeric: totalSize extraChars: additionallyAllowed mergeUID: minimalSizeOfRandomPart
>>> 	"Generates a String with unique identifier ( UID ) qualities, the difference to a
>>> 	 UUID is that its beginning is derived from the receiver, so that it has a meaning
>>> 	 for a human reader.
>>> 
>>> 	 Answers a String of totalSize, which consists of 3 parts
>>> 	 1.part: the beginning of the receiver only consisting of
>>> 		a-z, A-Z, 0-9 and extraChars in Collection additionallyAllowed ( which can be nil )
>>> 	 2.part: a single _
>>> 	 3.part: a ( random ) UID of size >= minimalSizeOfRandomPart consisting of
>>> 		a-z, A-Z, 0-9
>>> 
>>> 	 Starting letters are capitalized.
>>> 	 TotalSize must be at least 1.
>>> 	 Exactly 1 occurrence of $_ is guaranteed ( unless additionallyAllowed includes $_ ).
>>> 	 The random part has even for small sizes good UID qualitites for many practical purposes.
>>> 	 If only lower- or uppercase letters are demanded, simply convert the answer with
>>> 	 say #asLowercase. The probability of a duplicate will rise only moderately ( see below ).
>>> 
>>> 	 Example:
>>> 		size of random part = 10
>>> 		in n generated UIDs the chance p of having non-unique UIDs is
>>> 			n = 10000 ->  p < 1e-10		if answer is reduced to lowerCase: p < 1.4 e-8
>>> 			n = 100000 -> p < 1e-8
>>> 		at the bottom is a snippet for your own calculations
>>> 		Note: the calculated propabilites are theoretical,
>>> 			for the actually used random generator they may be much worse"
>>> 
>>> 	| stream out sizeOfFirstPart index ascii ch skip array random |
>>> 	totalSize > minimalSizeOfRandomPart
>>> 		ifFalse: [ self errorOutOfBounds ].
>>> 	stream := ReadStream on: self.
>>> 	out := WriteStream on: ( String new: totalSize ).
>>> 	index := 0.
>>> 	skip := true.
>>> 	sizeOfFirstPart := totalSize - minimalSizeOfRandomPart - 1.
>>> 	[ stream atEnd or: [ index >= sizeOfFirstPart ]]
>>> 	whileFalse: [
>>> 		((( ascii := ( ch := stream next ) asciiValue ) >= 65 and: [ ascii <= 90 ]) or: [
>>> 			( ascii >= 97 and: [ ascii <= 122 ]) or: [
>>> 			ch isDigit or: [
>>> 			additionallyAllowed notNil and: [ additionallyAllowed includes: ch ]]]])
>>> 		ifTrue: [
>>> 			skip
>>> 				ifTrue: [ out nextPut: ch asUppercase ]
>>> 				ifFalse: [ out nextPut: ch ].
>>> 			index := index + 1.
>>> 			skip := false ]
>>> 		ifFalse: [ skip := true ]].
>>> 	out nextPut: $_.
>>> 	array := Array new: 62.
>>> 	1 to: 26 do: [ :i |
>>> 		array at: i put: ( i + 64 ) asCharacter.
>>> 		array at: i + 26 put: ( i + 96 ) asCharacter ].
>>> 	53 to: 62 do: [ :i |
>>> 		array at: i put: ( i - 5 ) asCharacter ].
>>> + 	random := ThreadSafeRandom value.
>>> - 	random := UUIDGenerator default randomGenerator.
>>> 	totalSize - index - 1 timesRepeat: [
>>> 		out nextPut: ( array atRandom: random )].
>>> 	^out contents
>>> 
>>> 	"	calculation of probability p for failure of uniqueness in n UIDs
>>> 		Note: if answer will be converted to upper or lower case replace 62 with 36
>>> 	| n i p all |
>>> 	all := 62 raisedTo: sizeOfRandomPart.
>>> 	i := 1.
>>> 	p := 0.0 .
>>> 	n := 10000.
>>> 	[ i <= n ]
>>> 	whileTrue: [
>>> 		p := p + (( i - 1 ) / all ).
>>> 		i := i + 1 ].
>>> 	p
>>> 
>>> 	approximation formula: n squared / ( 62.0 raisedTo: sizeOfRandomPart ) / 2
>>> 	"
>>> 
>>> 	"'Crop SketchMorphs and Grab Screen Rect to JPG'
>>> 			asAlphaNumeric: 31 extraChars: nil mergeUID: 10
>>> 	 			'CropSketchMorphsAndG_iOw94jquN6'
>>> 	 'Monticello'
>>> 			asAlphaNumeric: 31 extraChars: nil mergeUID: 10
>>> 				'Monticello_kp6aV2l0IZK9uBULGOeG'
>>> 	 'version-', ( '1.1.2' replaceAll: $. with: $- )
>>> 			asAlphaNumeric: 31 extraChars: #( $- ) mergeUID: 10
>>> 				'Version-1-1-2_kuz2tMg2xX9iRLDVR'"
>>> 		!
>>> 
>>> Item was changed:
>>> ----- Method: UUID>>initialize (in category 'initalize-release') -----
>>> initialize
>>> + 	self makeUUID.!
>>> - 	self primMakeUUID.!
>>> 
>>> Item was added:
>>> + ----- Method: UUID>>makeUUID (in category 'as yet unclassified') -----
>>> + makeUUID
>>> + 	UUIDGenerator default generateBytes: self forVersion: 4.!
>>> 
>>> Item was changed:
>>> ----- Method: UUID>>primMakeUUID (in category 'system primitives') -----
>>> primMakeUUID
>>> 	<primitive: 'primitiveMakeUUID' module: 'UUIDPlugin'>
>>> + 	self makeUUID!
>>> - 	UUIDGenerator default generateBytes: self forVersion: 4.!
>>> 
>>> Item was changed:
>>> Object subclass: #UUIDGenerator
>>> + 	instanceVariableNames: 'bits'
>>> + 	classVariableNames: 'Default TheRandom TheSemaphore'
>>> - 	instanceVariableNames: 'timeLow timeMid timeHiAndVersion clockSeqHiAndReserved clockSeqLow node randomCounter randomGenerator semaphoreForGenerator'
>>> - 	classVariableNames: 'Default'
>>> 	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.
>>> - !UUIDGenerator commentStamp: '<historical>' prior: 0!
>>> - This class generates a pseudo-random UUID
>>> - by John M McIntosh johnmci at smalltalkconsulting.com
>>> 
>>> + See https://tools.ietf.org/html/rfc4122.html#section-4.4 for reference.!
>>> - See http://www.webdav.org/specs/draft-leach-uuids-guids-01.txt!
>>> 
>>> Item was changed:
>>> ----- Method: UUIDGenerator class>>initialize (in category 'class initialization') -----
>>> initialize
>>> + 	TheRandom := Random new.
>>> + 	TheSemaphore := Semaphore forMutualExclusion.
>>> 	Smalltalk addToStartUpList: self after: nil.!
>>> 
>>> Item was changed:
>>> ----- Method: UUIDGenerator>>generateFieldsVersion4 (in category 'instance creation') -----
>>> generateFieldsVersion4
>>> +
>>> + 	TheSemaphore critical: [
>>> + 		bits := 16rffffffffffffffffffffffffffffffff atRandom: TheRandom. "128 bit"].!
>>> -
>>> - 	timeLow := self generateRandomBitsOfLength: 32.
>>> - 	timeMid := self generateRandomBitsOfLength: 16.
>>> - 	timeHiAndVersion := 16r4000 bitOr: (self generateRandomBitsOfLength: 12).
>>> - 	clockSeqHiAndReserved := 16r80 bitOr: (self generateRandomBitsOfLength: 6).
>>> - 	clockSeqLow := self generateRandomBitsOfLength: 8.
>>> - 	node := self generateRandomBitsOfLength: 48.
>>> - 	!
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>generateOneOrZero (in category 'generator') -----
>>> - generateOneOrZero
>>> - 	^self semaphoreForGenerator
>>> - 		critical: [| value |
>>> - 			value := self randomGenerator next.
>>> - 			self randomCounter: self randomCounter + 1.
>>> - 			self randomCounter > 100000
>>> - 				ifTrue: [self setupRandom].
>>> - 			value < 0.5
>>> - 				ifTrue: [0]
>>> - 				ifFalse: [1]].!
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>generateRandomBitsOfLength: (in category 'generator') -----
>>> - generateRandomBitsOfLength: aNumberOfBits
>>> - | target |
>>> - 	target := 0.
>>> - 	aNumberOfBits isZero ifTrue: [^target].
>>> - 	target := self generateOneOrZero.
>>> - 	(aNumberOfBits - 1)  timesRepeat:
>>> - 		[target := (target bitShift: 1)  bitOr: self generateOneOrZero].
>>> - 	^target!
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>initialize (in category 'instance creation') -----
>>> - initialize
>>> - 	self setupRandom.
>>> - 	semaphoreForGenerator := Semaphore forMutualExclusion.
>>> - 	!
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>makeSeed (in category 'random seed') -----
>>> - makeSeed
>>> - 	"Try various methods of getting good seeds"
>>> - 	| seed |
>>> - 	seed := self makeUnixSeed.
>>> - 	seed ifNotNil: [^seed].
>>> -
>>> - 	"not sure if this is reliably random... commented out for now. -dew"
>>> - 	"seed := self makeSeedFromSound.
>>> - 	seed ifNotNil: [^seed]."
>>> -
>>> - 	"default"
>>> - 	[seed := (Time millisecondClockValue bitAnd: 16r3FFFFFFF) bitXor: self hash.
>>> - 	seed := seed bitXor: (Time totalSeconds bitAnd: 16r3FFFFFFF).
>>> - 	seed = 0] whileTrue: ["Try again if ever get a seed = 0"].
>>> -
>>> - 	^seed
>>> - !
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>makeSeedFromSound (in category 'random seed') -----
>>> - makeSeedFromSound
>>> - 	^[SoundService default randomBitsFromSoundInput: 32]
>>> - 		ifError: [nil].!
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>makeUnixSeed (in category 'random seed') -----
>>> - makeUnixSeed
>>> -
>>> - 	^[
>>> - 		StandardFileStream readOnlyFileNamed: '/dev/urandom' do: [ :stream |
>>> - 			stream binary.
>>> - 			(Integer
>>> - 				byte1: stream next
>>> - 				byte2: stream next
>>> - 				byte3: stream next
>>> - 				byte4: stream next) ] ]
>>> - 		on: Error
>>> - 		do: [ nil ]!
>>> 
>>> Item was changed:
>>> ----- 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.!
>>> - 	aByteArray at: 1 put: ((timeLow bitShift: -24) bitAnd: 16rFF).
>>> - 	aByteArray at: 2 put: ((timeLow bitShift: -16) bitAnd: 16rFF).
>>> - 	aByteArray at: 3 put: ((timeLow bitShift: -8) bitAnd: 16rFF).
>>> - 	aByteArray at: 4 put: (timeLow bitAnd: 16rFF).
>>> - 	aByteArray at: 5 put: ((timeMid bitShift: -8) bitAnd: 16rFF).
>>> - 	aByteArray at: 6 put: (timeMid bitAnd: 16rFF).
>>> - 	aByteArray at: 7 put: ((timeHiAndVersion bitShift: -8) bitAnd: 16rFF).
>>> - 	aByteArray at: 8 put: (timeHiAndVersion bitAnd: 16rFF).
>>> - 	aByteArray at: 9 put: clockSeqHiAndReserved.
>>> - 	aByteArray at: 10 put: clockSeqLow.
>>> - 	0 to: 5 do: [:i |
>>> - 		aByteArray at: 11 + i put: ((node bitShift: (-8*i)) bitAnd: 16rFF)]
>>> - !
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>randomCounter (in category 'accessors and mutators') -----
>>> - randomCounter
>>> - 	^randomCounter!
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>randomCounter: (in category 'accessors and mutators') -----
>>> - randomCounter: aNumber
>>> - 	randomCounter := aNumber
>>> - !
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>randomGenerator (in category 'accessors and mutators') -----
>>> - randomGenerator
>>> - 	^randomGenerator
>>> - !
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>randomGenerator: (in category 'accessors and mutators') -----
>>> - randomGenerator: aGenerator
>>> - 	randomGenerator := aGenerator
>>> - !
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>semaphoreForGenerator (in category 'accessors and mutators') -----
>>> - semaphoreForGenerator
>>> - 	^semaphoreForGenerator!
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>semaphoreForGenerator: (in category 'accessors and mutators') -----
>>> - semaphoreForGenerator: aSema
>>> - 	semaphoreForGenerator := aSema
>>> - !
>>> 
>>> Item was removed:
>>> - ----- Method: UUIDGenerator>>setupRandom (in category 'instance creation') -----
>>> - setupRandom
>>> - 	randomCounter := 0.
>>> - 	randomGenerator := Random seed: self makeSeed.!