"
This class is not covered by or part of the ST/X licence.
COPYRIGHT.
The above file is a Manchester Goodie protected by copyright.
These conditions are imposed on the whole Goodie, and on any significant
part of it which is separately transmitted or stored:
* You must ensure that every copy includes this notice, and that
source and author(s) of the material are acknowledged.
* These conditions must be imposed on anyone who receives a copy.
* The material shall not be used for commercial gain without the prior
written consent of the author(s).
Further information on the copyright conditions may be obtained by
sending electronic mail:
To: goodies-lib@cs.man.ac.uk
Subject: copyright
or by writing to The Smalltalk Goodies Library Manager, Dept of
Computer Science, The University, Manchester M13 9PL, UK
(C) Copyright 1993 University of Manchester
For more information about the Manchester Goodies Library (from which
this file was distributed) send e-mail:
To: goodies-lib@cs.man.ac.uk
Subject: help
"
SequenceableCollection subclass:#RunArray
instanceVariableNames:'contentsArray'
classVariableNames:''
poolDictionaries:''
category:'Collections-Sequenceable'
!
RunArray comment:'This implements an ordered collection which uses runs to minimise the amount
of data that it holds. Basically it should be used if you know that an ordered
collections is giong to contain a lot of runs of eactly the same data. Implemented
to allow simultation playback, since the ordered collctions which that generates
are so big that the complier falls over, though most of it is extremely repetetive.
This should be totally abstracted. The user should not be a ble to see the difference
between an ordered collection and a ComrpessedOrderedCollection. This has a
lot in common with RunArray, and the two should probably share implementation.
but I could not do some of the things I wanted with the RunArray code, so this
is all done on its own.
Some of this could be made faster by adding a cache of the start and finish
indices of each run, but since I envisage that most additions etc. will be to
and from the end those are not included. In addition I have implemented the
bare essentials of this for what I need it for - i.e. add to the end and take
off the beginning.'!
!RunArray class methodsFor:'documentation'!
copyright
"
This class is not covered by or part of the ST/X licence.
COPYRIGHT.
The above file is a Manchester Goodie protected by copyright.
These conditions are imposed on the whole Goodie, and on any significant
part of it which is separately transmitted or stored:
* You must ensure that every copy includes this notice, and that
source and author(s) of the material are acknowledged.
* These conditions must be imposed on anyone who receives a copy.
* The material shall not be used for commercial gain without the prior
written consent of the author(s).
Further information on the copyright conditions may be obtained by
sending electronic mail:
To: goodies-lib@cs.man.ac.uk
Subject: copyright
or by writing to The Smalltalk Goodies Library Manager, Dept of
Computer Science, The University, Manchester M13 9PL, UK
(C) Copyright 1993 University of Manchester
For more information about the Manchester Goodies Library (from which
this file was distributed) send e-mail:
To: goodies-lib@cs.man.ac.uk
Subject: help
"
!
documentation
"
This implements an array which uses runs to minimise the amount
of data that it holds.
Basically it should be used if you know that an array is going to contain
a lot of runs of exactly the same data.
RunArrays are used by the Text class to keep character attributes
(which we expect to remain constant for longer character ranges).
Notice:
there is only a space saving if there are really runs (i.e. multiple
elements which compare same).
Otherwise, an Array is more compact.
[instance variables:]
runs <Array> contains the runs, consisting of
length/value entries.
[implementation note:]
structure-wise, it would have been more intuitive, to keep
instances of Run objects (as done in CompressedOrderedCollection)
instead of alternating length/values in the `runs' collection.
However, doing this means that lots of additional memory is required.
Here, we choose the more space efficient way.
[author:]
Claus Gittinger
[see also:]
Array OrderedCollection CompressedOrderedCollection
"
!
examples
"
this eats up a lot of memory ...
... but its relatively fast:
[exBegin]
|coll|
coll := OrderedCollection new.
Transcript showCr:(
Time millisecondsToRun:[
100000 timesRepeat:[coll add:'hello'].
100000 timesRepeat:[coll add:'world'].
]
).
coll inspect.
[exEnd]
this is very space efficient ...
... (and even slightly faster):
[exBegin]
|coll|
coll := RunArray new.
Transcript showCr:(
Time millisecondsToRun:[
100000 timesRepeat:[coll add:'hello'].
100000 timesRepeat:[coll add:'world'].
]
).
coll inspect.
[exEnd]
this is very space efficient ...
... AND much faster:
[exBegin]
|coll|
coll := RunArray new.
Transcript showCr:(
Time millisecondsToRun:[
coll add:'hello' withOccurrences:100000.
coll add:'world' withOccurrences:100000.
]
).
coll inspect.
[exEnd]
this is very space INEFFICIENT (a real memory pig ;-) ...
... and much slower:
[exBegin]
|coll|
coll := RunArray new.
Transcript showCr:(
Time millisecondsToRun:[
1 to:1000 do:[:i | coll add:i].
]
).
coll inspect.
[exEnd]
"
! !
!RunArray class methodsFor:'instance creation'!
new:size
"ignore the size argument - we dont know how many runs are
needed - anyway"
^ self new
! !
!RunArray methodsFor:'accessing'!
at:anInteger
"Answer the element at index anInteger.
at: is used by a knowledgeable client to access an existing element
This is a pretty dumb thing to do to a runArray and it is
not at all efficient (think of that as a discouragement)."
|position "{ Class: SmallInteger }"
nRuns "{ Class: SmallInteger }"|
(anInteger > 0) ifTrue:[
position := 1.
nRuns := contentsArray size.
1 to:nRuns by:2 do:[:runIndex |
|runLen|
runLen := contentsArray at:runIndex.
anInteger >= position ifTrue:[
anInteger < (position + runLen) ifTrue:[
^ contentsArray at:(runIndex + 1)
].
].
position := position + runLen
]
].
^ self errorInvalidKey:anInteger
"
|c|
c := RunArray new.
c add:1; add:1; add:1; add:2; add:2; add:3; add:3; add:4; add:5.
c at:1.
c at:2.
c at:3.
c at:4.
c at:5.
c at:6.
c at:7.
c at:8.
c at:9.
c at:10.
"
"Modified: 11.5.1996 / 13:33:50 / cg"
!
at:index put:anObject
"Put anObject at element index anInteger.
at:put: can not be used to append, front or back, to an ordered
collection; it is used by a knowledgeable client to replace an
element.
This is a pretty dumb thing to do to a runArray and it is
very inefficient, since we have to check if runs are to be merged or
splitted."
|runSz runIndex runOffset len l1 l2 prevIdx nextIdx
val newRuns newValues prevLen prevVal nextLen nextVal idx|
runSz := contentsArray size.
runIndex := nil.
(index > 0) ifTrue:[
runOffset := 1.
idx := 1.
[runIndex isNil and:[idx < runSz]] whileTrue:[
len := contentsArray at:idx.
nextIdx := runOffset + len.
index >= runOffset ifTrue:[
index < nextIdx ifTrue:[
runIndex := idx.
nextIdx := runOffset. "/ dont advance
].
].
runOffset := nextIdx.
idx := idx + 2.
]
].
runIndex isNil ifTrue:[
^ self errorInvalidKey:index
].
val := contentsArray at:(runIndex + 1).
"/ easiest: value there is the same ...
val = anObject ifTrue:[
^ anObject
].
"/ if the length is 1, this is an island ...
"/ ... which is either easy, or requires a merge.
len := contentsArray at:runIndex.
len = 1 ifTrue:[
"/ check if it can be merged into the next or previous run
runIndex > 1 ifTrue:[
prevIdx := runIndex - 2.
prevVal := contentsArray at:(prevIdx + 1).
prevVal = anObject ifTrue:[
"/ can merge it into previous
prevLen := contentsArray at:prevIdx.
"/ check if merge into next is also possible (filling an island)
runIndex < (runSz - 1) ifTrue:[
nextIdx := runIndex + 2.
nextVal := contentsArray at:(nextIdx + 1).
nextVal = anObject ifTrue:[
"/ can merge with both.
nextLen := contentsArray at:nextIdx.
contentsArray at:prevIdx put:prevLen+nextLen+1.
runSz := (runSz - 4).
newRuns := Array new:runSz.
newRuns replaceFrom:1 to:(prevIdx + 1) with:contentsArray startingAt:1.
newRuns replaceFrom:runIndex to:runSz with:contentsArray startingAt:nextIdx+2.
contentsArray := newRuns.
^ anObject
]
].
contentsArray at:prevIdx put:prevLen+1.
runSz := (runSz - 2).
newRuns := Array new:runSz.
newRuns replaceFrom:1 to:(runIndex - 1) with:contentsArray startingAt:1.
newRuns replaceFrom:runIndex to:runSz with:contentsArray startingAt:runIndex+2.
contentsArray := newRuns.
^ anObject
].
].
"/ check if merge into next is possible
runIndex < runSz ifTrue:[
nextIdx := runIndex + 2.
nextVal := contentsArray at:nextIdx+1.
nextVal = anObject ifTrue:[
nextLen := contentsArray at:nextIdx.
contentsArray at:nextIdx put:nextLen + 1.
runSz := (runSz - 2).
newRuns := Array new:runSz.
newRuns replaceFrom:1 to:(runIndex - 1) with:contentsArray startingAt:1.
newRuns replaceFrom:runIndex to:runSz with:contentsArray startingAt:nextIdx.
contentsArray := newRuns.
^ anObject
].
].
"/ no merge; island remains
contentsArray at:(runIndex+1) put:anObject.
^ anObject
].
runOffset == index ifTrue:[
"/ at the beginning of that run ...
"/ check if its better added to the previous run ...
runIndex > 1 ifTrue:[
prevIdx := runIndex - 2.
prevVal := contentsArray at:prevIdx+1.
prevVal = anObject ifTrue:[
prevLen := contentsArray at:prevIdx.
contentsArray at:prevIdx put:prevLen + 1.
contentsArray at:runIndex put:len - 1.
^ anObject.
].
].
"/ must cut off 1 & insert a new run before ..
contentsArray at:runIndex put:len - 1.
runSz := (runSz + 2).
newRuns := Array new:runSz.
newRuns replaceFrom:1 to:(runIndex - 1) with:contentsArray startingAt:1.
newRuns replaceFrom:runIndex+2 to:runSz with:contentsArray startingAt:runIndex.
contentsArray := newRuns.
contentsArray at:runIndex put:1.
contentsArray at:runIndex+1 put:anObject.
^ anObject
].
(runOffset + len - 1) == index ifTrue:[
"/ at the end ...
"/ check if its better added to the next run ...
runIndex < runSz ifTrue:[
nextIdx := runIndex + 2.
nextVal := contentsArray at:nextIdx+1.
nextVal = anObject ifTrue:[
nextLen := contentsArray at:nextIdx.
contentsArray at:nextIdx put:nextLen + 1.
contentsArray at:runIndex put:len - 1.
^ anObject.
].
].
"/ must cut off 1 & insert a new run after ..
contentsArray at:runIndex put:len - 1.
runSz := (runSz + 2).
newRuns := Array new:runSz.
newRuns replaceFrom:1 to:(runIndex + 1) with:contentsArray startingAt:1.
newRuns replaceFrom:runIndex+4 to:runSz with:contentsArray startingAt:runIndex+2.
contentsArray := newRuns.
contentsArray at:runIndex+2 put:1.
contentsArray at:runIndex+2+1 put:anObject.
^ anObject
].
"/ hardest - split run into two, insert new run in-between
runSz := (runSz + 4).
newRuns := Array new:runSz.
runIndex > 1 ifTrue:[
newRuns replaceFrom:1 to:runIndex-1 with:contentsArray.
].
newRuns replaceFrom:runIndex+6 to:(runSz+4) with:contentsArray startingAt:runIndex+2.
l2 := len - (index - runOffset).
l1 := len - l2.
l2 := l2 - 1.
newRuns at:runIndex put:l1.
newRuns at:runIndex+1 put:val.
newRuns at:runIndex+4 put:l2.
newRuns at:runIndex+5 put:val.
"/ insert
newRuns at:runIndex+2 put:1.
newRuns at:runIndex+3 put:anObject.
contentsArray := newRuns.
^ anObject
"
|c|
Transcript cr.
c := RunArray new.
c add:1; add:1; add:1; add:2; add:2; add:3; add:3; add:4; add:5; yourself.
Transcript showCr:c.
c at:1 put:$a.
Transcript showCr:c.
c.
c at:3 put:$a.
Transcript showCr:c.
c.
c at:4 put:$a.
Transcript showCr:c.
c.
c at:5 put:$a.
Transcript showCr:c.
c.
c at:2 put:$0.
Transcript showCr:c.
c.
c at:2 put:$a.
Transcript showCr:c.
c.
Transcript showCr:c.
"
"Modified: 11.5.1996 / 13:34:21 / cg"
!
size
"Answer how many elements the receiver contains.
Thsi is not the number of runs (but the simulated number of elements)."
|n "{ Class: SmallInteger }"
runSz "{ Class: SmallInteger }"|
n := 0.
runSz := contentsArray size.
1 to:runSz by:2 do:[:i |
n := n + (contentsArray at:i)
].
^ n
"Modified: 11.5.1996 / 13:34:27 / cg"
! !
!RunArray methodsFor:'adding'!
add:newObject
"add newObject at the end; returns the object (sigh)"
^ self add:newObject withOccurrences:1.
"
|c|
c := RunArray new.
c add:1; add:1; add:1; add:2; add:2; add:3; add:3; add:4; add:5; yourself.
"
"Modified: 10.5.1996 / 17:01:20 / cg"
!
add:newObject withOccurrences:n
"add newObject n times at the end; returns the object (sigh)"
|lastIdx runSz newRuns|
contentsArray notNil ifTrue:[
"/ check for merge
runSz := contentsArray size.
(contentsArray at:runSz) = newObject ifTrue:[
lastIdx := runSz - 1.
contentsArray at:lastIdx put:(contentsArray at:lastIdx) + n.
^ newObject
].
newRuns := Array new:(runSz + 2).
newRuns replaceFrom:1 to:runSz with:contentsArray.
newRuns at:runSz+1 put:n.
newRuns at:runSz+2 put:newObject.
contentsArray := newRuns.
] ifFalse:[
contentsArray := Array with:n with:newObject.
].
^ newObject
"
|c|
c := RunArray new.
c add:1 withOccurrences:1000; yourself.
c add:2 withOccurrences:1000; yourself.
"
"Modified: 11.5.1996 / 13:34:37 / cg"
!
grow:howBig
"grow or shrink the receiver to contain howBig elements.
If growing, new slots will be filled (logically) with nil."
|sz info runIndex runOffset runSz newRuns|
sz := self size.
howBig == sz ifTrue:[^ self].
howBig == 0 ifTrue:[
contentsArray := nil.
^ self.
].
contentsArray isNil ifTrue:[
contentsArray := Array with:howBig with:nil.
^ self
].
runSz := contentsArray size.
howBig > sz ifTrue:[
newRuns := Array new:(runSz + 2).
newRuns replaceFrom:1 to:runSz with:contentsArray startingAt:1.
newRuns at:(runSz+1) put:(howBig - sz).
contentsArray := newRuns.
^ self
].
"/ shrinking; possibly cut of a run
info := self runIndexAndStartIndexForIndex:howBig.
runIndex := info at:1.
runOffset := info at:2.
howBig == (runOffset - 1) ifTrue:[
"/ we are lucky - new size is up-to previous run
contentsArray := contentsArray copyFrom:1 to:runIndex-1.
] ifFalse:[
contentsArray := contentsArray copyFrom:1 to:(runIndex+1).
contentsArray at:runIndex put:(howBig - runOffset + 1)
].
"
|c|
c := RunArray new.
c addAll:#(1 2 3 4 4 4 4 5 5 5 1 2 3); yourself.
c grow:50; yourself.
c grow:7; yourself.
c grow:6; yourself.
c grow:0; yourself.
"
"Modified: 11.5.1996 / 13:34:53 / cg"
! !
!RunArray methodsFor:'converting'!
asOrderedCollection
"return a new orderedCollection, containing the receivers elements."
|newCollection|
contentsArray isNil ifTrue:[^ OrderedCollection new].
newCollection := OrderedCollection new:(self size).
contentsArray pairWiseDo:[:len :value |
newCollection add:value withOccurrences:len
].
^ newCollection
"
|r|
r := RunArray withAll:#(1 2 3 3 3 3 4 4 4 5 6 7 7 7 7 7 7 7).
Transcript showCr:r.
Transcript showCr:r asOrderedCollection
"
"Modified: 11.5.1996 / 13:34:59 / cg"
! !
!RunArray methodsFor:'enumerating'!
do:aBlock
"Evaluate aBlock with each of the receiver's elements as the
argument. "
contentsArray notNil ifTrue:[
contentsArray pairWiseDo:[:len :val |
len timesRepeat: [aBlock value:val]
]
]
"Modified: 11.5.1996 / 13:35:03 / cg"
! !
!RunArray methodsFor:'printing'!
storeOn:aStream
"Append to aStream an expression which, if evaluated, will generate
an object similar to the receiver."
aStream nextPutAll: '(RunArray new'.
contentsArray notNil ifTrue:[
contentsArray pairWiseDo:[:len :val |
aStream nextPutAll: ' add:'; nextPutAll:val storeString.
len == 1 ifFalse:[
aStream nextPutAll:' withCount:'; nextPutAll:len printString.
].
aStream nextPutAll:';'
].
aStream nextPutAll:' yourself'
].
aStream nextPutAll:')'
"
(RunArray new
add:1;
add:1;
add:2;
add:3;
add:4 withCount:100;
add:5;
yourself) storeString
RunArray new storeString
"
"Modified: 11.5.1996 / 13:35:08 / cg"
! !
!RunArray methodsFor:'private'!
find:oldObject
"If I contain oldObject return its index, otherwise create an error
notifier. It will answer with the position of the very first element of
that value."
|position|
position := self find:oldObject ifAbsent:0.
position ~~ 0 ifTrue:[
^ position
].
self errorValueNotFound:oldObject
"
|c|
c := RunArray new.
c add:1; add:1; add:1; add:2; add:2; add:3; add:3; add:4; add:5.
c find:2.
c find:99
"
"Modified: 10.5.1996 / 13:39:58 / cg"
!
find:oldObject ifAbsent:exceptionBlock
"If I contain oldObject return its index, otherwise execute the
exception block. It will answer with the position of the very first
element of that value."
|position|
position := 1.
contentsArray notNil ifTrue:[
contentsArray pairWiseDo:[:len :val |
val = oldObject ifTrue:[
^ position
].
position := position + len.
].
].
^ exceptionBlock value
"Modified: 11.5.1996 / 13:35:14 / cg"
!
isEmpty
"Am I empty or not. Returns a boolean"
^ contentsArray notNil
"Modified: 11.5.1996 / 13:35:17 / cg"
!
runIndexAndStartIndexForIndex:anIndex
"given a logical index, find the index of that run and the logical index
of the first item in that run."
|position nRuns "{ Class: SmallInteger }"|
position := 1.
nRuns := contentsArray size.
1 to:nRuns by:2 do:[:runIndex |
|runLen runLast|
runLen := contentsArray at:runIndex.
anIndex >= position ifTrue:[
runLast := position + runLen - 1.
anIndex <= runLast ifTrue:[
^ Array with:runIndex with:position
].
].
position := position + runLen
].
^ #(0 0)
"Created: 10.5.1996 / 17:12:28 / cg"
"Modified: 11.5.1996 / 13:35:21 / cg"
! !
!RunArray methodsFor:'user interface'!
inspect
"Reimplement so that they don't get an ordered collection inspector
which would get very confused."
self basicInspect
"Modified: 10.5.1996 / 18:24:43 / cg"
! !
!RunArray class methodsFor:'documentation'!
version
^ '$Header: /cvs/stx/stx/libbasic2/RunArray.st,v 1.3 1996-05-11 11:35:58 cg Exp $'
! !