instanceVariableNames:'name category instvars primitiveSpec signature'

	 classVariableNames:''

	 poolDictionaries:''

	 category:'Kernel-Classes'

!

version

    ^ '$Header: /cvs/stx/stx/libbasic/Attic/ClassDescr.st,v 1.21 1995-11-23 10:46:35 cg Exp $'

instVarAtOffset:index

    "return the name of the instance variable at index"

    ^ self allInstanceVariableNames at:index

!

instVarNames

    "return a collection of the instance variable name-strings"

    instvars isNil ifTrue:[

	^ OrderedCollection new

    ].

    ^ instvars asCollectionOfWords

    "

     Point instVarNames  

    "

!

instVarOffsetOf:aVariableName

    "return the index (as used in instVarAt:/instVarAt:put:) of a named instance

     variable. The returned number is 1..instSize for valid variable names, nil for

     illegal names."

    ^ self allInstVarNames indexOf:aVariableName ifAbsent:nil

!

instanceVariableOffsets

    "returns a dictionary containing the instance variable index

     for each instVar name"

    |dict index|

    index := 0. dict := Dictionary new.

    self allInstVarNames do:[:nm | index := index + 1. dict at:nm put:index].

    ^ dict

    "

     Point instanceVariableOffsets 

     GraphicsContext instanceVariableOffsets 

    "

!

instanceVariableString

    "return a string of the instance variable names"

    instvars isNil ifTrue:[^ ''].

    ^ instvars

    "

     Point instanceVariableString   

    "

!

name

    "return the name of the class. In the current implementation,

     this returns a string, but will be changed to Symbol soon."

    ^ name

!

!ClassDescription methodsFor:'renaming'!

renameTo:newName

    "change the name of the class"

    |oldSym|

    oldSym := name asSymbol.

    self setName:newName.

    Smalltalk at:oldSym put:nil.

    Smalltalk removeKey:oldSym.             "26.jun 93"

    Smalltalk at:(newName asSymbol) put:self.

! !

!ClassDescription methodsFor:'signature checking'!

classinstSizeFromSignature:aSignature

    "for checking class compatibility: return some number based on 

     the classinstSize from a signature key (not always the real classinstsize)."

    ^ (aSignature bitShift:-7) bitAnd:7

!

instNameKeyFromSignature:aSignature

    "for checking class compatibility: return a number based on the

     names and order of the instance variables from a signature key."

    ^ (aSignature bitShift:-14) bitAnd:16rFFFF

    "

     Point instNameKeyFromSignature:Point signature.             

     Association instNameKeyFromSignature:Association signature.  

    "

!

instSizeFromSignature:aSignature

    "for checking class compatibility: return the some number based on

     the instSize from a signature key (not always the real instSize)."

    ^ aSignature bitAnd:16r7F

    "

     Class instSizeFromSignature:Point signature.     

     Class instSizeFromSignature:Association signature.   

     Class instSizeFromSignature:Dictionary signature.    

    "

!

instTypeFromSignature:aSignature

    "for checking class compatibility: return some number based on

     the instType (i.e. variableBytes/Pointers etc.) from a signature key."

    ^ (aSignature bitShift:-10) bitAnd:(Class maskIndexType)

    "

     Class instTypeFromSignature:Object signature.               

     Class instTypeFromSignature:Array signature.                

     Class instTypeFromSignature:String signature.               

     Class instTypeFromSignature:OrderedCollection signature.    

    "

!

signature

    "return a signature number - this number is useful for a quick

     check for changed classes, and is done in the binary-object loader, 

     and the dynamic class loader.

     Do NOT change the algorithm here - others may depend on it.

     Also, the algorithm may change - so never interpret the returned value

     (if at all, use the access #XXXFromSignature: methods)"

    |value   "{ Class: SmallInteger }"

     nameKey "{ Class: SmallInteger }" |

    signature notNil ifTrue:[^ signature].

    value := self flags bitAnd:(Class maskIndexType).

    value := (value bitShift:3) + ((self class instSize - Class instSize) bitAnd:7).

    value := (value bitShift:7) + (self instSize bitAnd:16r7F).

    nameKey := 0.

    self allInstVarNames do:[:name |

	nameKey := nameKey bitShift:1.

	(nameKey bitAnd:16r10000) ~~ 0 ifTrue:[

	    nameKey := nameKey bitXor:1.

	    nameKey := nameKey bitAnd:16rFFFF.

	].

	nameKey := (nameKey + (name at:1) asciiValue) bitAnd:16rFFFF.

    ].

    value := value + (nameKey bitShift:14).

    signature := value.

    ^ value

    "

     Array signature

     ByteArray signature

     View signature

    "

! !

!ClassDescription methodsFor:'special accessing'!

setInstanceVariableString:aString

    "set the classes instvarnames string - no recompilation

     or updates are done and no changeList records are written.

     This is NOT for general use."

    instvars := aString.

!

setName:aString

    "set the classes name - be careful, it will be still

     in the Smalltalk dictionary - under another key.

     This is NOT for general use - see renameTo:"

    name := aString

! !