[squeak-dev] The Inbox: Collections-cmm.873.mcz

commits at source.squeak.org commits at source.squeak.org
Wed Jan 22 05:54:30 UTC 2020


Chris Muller uploaded a new version of Collections to project The Inbox:
http://source.squeak.org/inbox/Collections-cmm.873.mcz

==================== Summary ====================

Name: Collections-cmm.873
Author: cmm
Time: 21 January 2020, 11:54:25.478956 pm
UUID: 3ec60cd4-3b16-4cf7-98bf-bc85acaa4192
Ancestors: Collections-ul.871

Let #new: *always* be a performance-improving choice over #new, when the correct size is known.

=============== Diff against Collections-ul.871 ===============

Item was changed:
  ----- Method: HashedCollection class>>goodPrimeAtLeast: (in category 'sizing') -----
  goodPrimeAtLeast: lowerLimit
  	"Answer the smallest good prime >= lowerlimit.
  	If lowerLimit is larger than the largest known good prime, just make it odd.
  	Use linear search, and exponential search to speed up cases when lowerLimit is small (<2500 and <100000, respectively).
  	Assume that there are goodPrimes greater than 100000."
  	
  	| highIndex midIndex lowIndex prime |
- 	lowerLimit <= 7 ifTrue: [
- 		lowerLimit <= 3 ifTrue: [ ^3 ].
- 		lowerLimit <= 5 ifTrue: [ ^5 ].
- 		^7 ].
  	GoodPrimes ifNil: [ "migration only"
  		self initializeGoodPrimes ].
  	lowerLimit < 2500 ifTrue: [
  		"Use linear search when the limit is small. The boundary is based on measurements."
  		highIndex := 4. "skip 3 5 and 7"
  		[ (GoodPrimes at: highIndex) < lowerLimit ] whileTrue: [
  			highIndex := highIndex + 1 ].
  		^GoodPrimes at: highIndex ].
  	lowerLimit < 100000 
  		ifTrue: [
  			"Use exponential search when the limit is not too large. The boundary is based on measurements."
  			highIndex := 1.
  			[ (GoodPrimes at: highIndex) < lowerLimit ] whileTrue: [
  				highIndex := highIndex * 2 ].
  			lowIndex := highIndex // 2 + 1. "highIndex // 2 was smaller than lowerLimit" ]
  		ifFalse: [
  			"Regular binary search."
  			lowIndex := 1.
  			highIndex := GoodPrimes size.
  			"Check whether the largest prime would fit"
  			(GoodPrimes at: highIndex) < lowerLimit ifTrue: [
  				^lowerLimit bitOr: 1 ]. ].
  	[ highIndex - lowIndex <= 1 ] whileFalse: [
  		midIndex := highIndex + lowIndex // 2.
  		prime := GoodPrimes at: midIndex.
  		lowerLimit < prime
  			ifTrue: [ highIndex := midIndex ]
  			ifFalse: [
  				lowerLimit > prime
  					ifTrue: [ lowIndex := midIndex ]
  					ifFalse: [ ^prime ] ] ].
  	(GoodPrimes at: lowIndex) >= lowerLimit ifTrue: [ ^GoodPrimes at: lowIndex ].
  	^GoodPrimes at: highIndex!

Item was changed:
  ----- Method: HashedCollection class>>new: (in category 'instance creation') -----
+ new: numberOfElements 
+ 	"Create a Set large enough to hold numberOfElements without growing"
+ 	^ self basicNew initialize:
+ 		(numberOfElements < 3
+ 			ifTrue: [ 3 ]
+ 			ifFalse:
+ 				[ numberOfElements < 4
+ 					ifTrue: [ 5 ]
+ 					ifFalse: [ self sizeFor: numberOfElements ] ])!
- new: nElements
- 	"Create a Set large enough to hold nElements without growing"
- 	^ self basicNew initialize: (self sizeFor: nElements)!



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