"

 COPYRIGHT (c) 1993 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

ArrayedCollection subclass:#UninterpretedBytes

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'Collections-Abstract'

!

!UninterpretedBytes class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1993 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    UninterpretedBytes provides the common protocol for byte-storage 

    containers; concrete subclasses are 

	ByteArray (which store the bytes within the

    		   Smalltalk object memory) 

    and 

	ExternalBytes (which store the bytes in the malloc-heap).

    UninterpretedBytes itself is abstract, so no instances of it can be created.

    [author:]

        Claus Gittinger

    [See also:]

        ByteArray String ExternalBytes

    [author:]

        Claus Gittinger

"

! !

!UninterpretedBytes class methodsFor:'queries'!

isBigEndian

    "return true, if words/shorts store the most-significant

     byte first (MSB), false if least-sign.-first (LSB). 

     I.e. false for vax, intel; true for m68k, sun."

%{  /* NOCONTEXT */

    /*

     * I dont like ifdefs - you always forget some ...

     * therefore we look into a structure at run-time

     */

    union {

	unsigned int   u_l;

	char           u_c[sizeof(int)];

    } u;

    u.u_l = 0x87654321;

    if (u.u_c[0] == 0x21) RETURN (false);

    RETURN (true);

%}

    "UninterpretedBytes isBigEndian"

isBuiltInClass

    "return true if this class is known by the run-time-system.

     Here, true is returned, since ByteStore is the superclass of

     some builtIn classes (ByteArray & ExternalBytes)"

    ^ self == UninterpretedBytes

    "Modified: 23.4.1996 / 15:56:25 / cg"

! !

!UninterpretedBytes methodsFor:'accessing'!

basicAt:index

    "return the indexed instance variable with index, anInteger.

     This must be provided by a concrete subclass."

    ^ self subclassResponsibility

!

basicAt:index put:value

    "set the indexed instance variable with index, anInteger to value.

     Returns value (sigh).

     This must be provided by a concrete subclass."

    ^ self subclassResponsibility

!

byteAt:index

    "return the byte at index. 

     For ByteArray, this is the same as basicAt:; 

     however, for strings or symbols, this returns a numeric byteValue

     instead of a character."

    ^ self subclassResponsibility

!

byteAt:index put:value

    "set the byte at index. For ByteArray, this is the same as basicAt:put:.

     However, for Strings, this expects a byteValue to be stored."

    ^ self subclassResponsibility

!

doubleAt:index

    "return the 8-bytes starting at index as a Float.

     Notice, that (currently) ST/X Floats are what Doubles are in ST-80.

     Notice also, that the bytes are expected to be in this machines

     float representation - if the bytearray originated from another

     machine, some conversion is usually needed."

    |newFloat|

    newFloat := Float basicNew.

    1 to:8 do:[:destIndex|

	newFloat basicAt:destIndex put:(self at:index - 1 + destIndex)

    ].

    ^ newFloat.

!

doubleAt:index put:aFloat

    "store the value of the argument, aFloat into the receiver

     starting at index.

     Notice, that (currently) ST/X Floats are what Doubles are in ST-80.

     Notice also, that the bytes are expected to be in this machines

     float representation - if the bytearray originated from another

     machine, some conversion is usually needed."

    |flt|

    flt := aFloat asFloat.

    1 to:8 do:[:srcIndex|

        self at:index - 1 + srcIndex put:(flt basicAt:srcIndex)

    ].

    ^ aFloat

!

doubleWordAt:index

    "return the 4-bytes starting at index as an (unsigned) Integer.

     The value is retrieved in the machines natural byte order.

     Subclasses may redefine this for better performance."

    ^ self doubleWordAt:index MSB:(UninterpretedBytes isBigEndian)

    "

     |b|

     b := ByteArray withAll:#(1 2 3 4).

     (b doubleWordAt:1) printStringRadix:16   

    "

!

doubleWordAt:index MSB:msb

    "return the 4-bytes starting at index as an (unsigned) Integer.

     The value is retrieved MSB-first, if the msb-arg is true;

     LSB-first otherwise.

     Subclasses may redefine this for better performance."

    |v|

    msb ifTrue:[

        v := self at:index.

        1 to:3 do:[:i |

            v := (v bitShift:8) bitOr:(self at:index+i)

        ].

    ] ifFalse:[

	v := self at:index+3.

	2 to:0 by:-1 do:[:i |

	    v := (v bitShift:8) bitOr:(self at:index+i)

	]

    ].

    ^ v

    "

     |b|

     b := ByteArray withAll:#(1 2 3 4).

     (b doubleWordAt:1 MSB:true) printStringRadix:16.   

     (b doubleWordAt:1 MSB:false) printStringRadix:16   

    "

!

doubleWordAt:index put:value

    "set the 4-bytes starting at index from the (unsigned) Integer value.

     The value should be in the range 0 to 16rFFFFFFFF

     (for negative values, the stored value is not defined).

     The value is stored in the machines natural byte order.

     Subclasses may redefine this for better performance."

    ^ self doubleWordAt:index put:value MSB:(UninterpretedBytes isBigEndian)

    "

     |b|

     b := ByteArray new:4.

     b doubleWordAt:1 put:16r04030201.

     b inspect

    "

!

doubleWordAt:index put:value MSB:msb

    "set the 4-bytes starting at index from the (unsigned) Integer value.

     The value must be in the range 0 to 16rFFFFFFFF.

     The value is stored MSB-first if msb is true; LSB-first otherwise.

     Subclasses may redefine this for better performance."

    |v|

    ((value < 0) or:[value > 16rFFFFFFFF]) ifTrue:[

	^ self elementBoundsError

    ].

    v := value.

    msb ifTrue:[

        3 to:0 by:-1 do:[:i |

            self at:index+i put:(v bitAnd:16rFF).

	    v := v bitShift:-8

        ].

    ] ifFalse:[

        0 to:3 by:-1 do:[:i |

            self at:index+i put:(v bitAnd:16rFF).

	    v := v bitShift:-8

        ]

    ].

    ^ value

    "

     |b|

     b := ByteArray new:8.

     b doubleWordAt:1 put:16r04030201 MSB:true.

     b doubleWordAt:5 put:16r04030201 MSB:false.

     b inspect

    "

!

floatAt:index

    "return the 4-bytes starting at index as a Float.

     Notice, that (currently) ST/X Floats are what Doubles are in ST-80;

     therefore this method reads a 4-byte float from the byteArray and returns

     a float object which keeps an 8-byte double internally.

     Notice also, that the bytes are expected to be in this machines

     float representation and order - if the bytearray originated from another

     machine, some conversion is usually needed."

    |newFloat|

    newFloat := ShortFloat basicNew.

    1 to:4 do:[:destIndex|

        newFloat basicAt:destIndex put:(self at:index - 1 + destIndex)

    ].

    ^ newFloat.

!

floatAt:index put:aFloat

    "store the 4 bytes of value of the argument, aFloat into the receiver

     starting at index.

     Notice, that (currently) ST/X Floats are what Doubles are in ST-80.

     Notice also, that the bytes are expected to be in this machines

     float representation - if the bytearray originated from another

     machine, some conversion is usually needed."

    |sflt|

    sflt := aFloat asShortFloat.

    1 to:4 do:[:srcIndex|

        self at:index - 1 + srcIndex put:(sflt basicAt:srcIndex)

    ].

    ^ aFloat

!

ieeDoubleAt:index

    "retrieve the 8 bytes starting at index as a float.

     The 8 bytes are assumed to be in IEE floating point single precision

     number format."

    "

     currently, we assume that the machines native number format is already

     IEE format - we need some more code here whenever ST/X is ported

     to an IBM 370 or old VAX etc.

     To date, all supported systems use IEE float numbers, so there should be

     no problem.

    "

    ^ self doubleAt:index

!

ieeDoubleAt:index put:aFloat

    "store the value of the argument, aFloat into the receiver

     starting at index. Storage is in IEE floating point double precision format.

     (i.e. 8 bytes are stored)."

    "

     currently, we assume that the machines native number format is already

     IEE format - we need some more code here whenever ST/X is ported

     to an IBM 370 or old VAX etc.

     To date, all supported systems use IEE float numbers, so there should be

     no problem.

    "

    ^ self doubleAt:index put:aFloat

!

ieeFloatAt:index

    "retrieve the 4 bytes starting at index as a float.

     The 4 bytes are assumed to be in IEE floating point single precision

     number format."

    "

     currently, we assume that the machines native number format is already

     IEE format - we need some more code here whenever ST/X is ported

     to an IBM 370 or old VAX etc.

     To date, all supported systems use IEE float numbers, so there should be

     no problem.

    "

    ^ self floatAt:index

!

ieeFloatAt:index put:aFloat

    "store the value of the argument, aFloat into the receiver

     starting at index. Storage is in IEE floating point single precision format.

     (i.e. 4 bytes are stored). Since ST/X floats are really doubles, the low-

     order 4 bytes of the precision is lost."

    "

     currently, we assume that the machines native number format is already

     IEE format - we need some more code here whenever ST/X is ported

     to an IBM 370 or old VAX etc.

     To date, all supported systems use IEE float numbers, so there should be

     no problem.

    "

    ^ self floatAt:index put:aFloat

!

quadWordAt:index MSB:msb

    "return the 8-bytes starting at index as an (unsigned) Integer.

     Depending on msb, the value is retrieved MSB or LSB-first."

    |l 

     bIdx  "{ Class: SmallInteger }"

     delta "{ Class: SmallInteger }"|

    l := LargeInteger basicNew numberOfDigits:8.

    msb ifTrue:[

	bIdx := index + 7.

	delta := -1

    ] ifFalse:[

	bIdx := index.

	delta := 1

    ].

    1 to:8 do:[:i |

	l digitAt:i put:(self basicAt:bIdx).

	bIdx := bIdx + delta

    ].

    ^ l compressed

    "

     |b|

     b := ByteArray withAll:#(1 2 3 4 5 6 7 8).

     (b quadWordAt:1 MSB:false) printStringRadix:16  

    "

    "Modified: 5.11.1996 / 14:06:21 / cg"

!

quadWordAt:index put:anInteger MSB:msb

    "set the 8-bytes starting at index from the (unsigned) Integer value.

     The value must be in the range 0 to 16rFFFFFFFFFFFFFFFF.

     Depending on msb, the value is stored MSB-first or LSB-first."

    |bIdx  "{ Class: SmallInteger }"

     delta "{ Class: SmallInteger }"|

    ((anInteger < 0) or:[anInteger > 16rFFFFFFFFFFFFFFFF]) ifTrue:[

	^ self elementBoundsError

    ].

    msb ifTrue:[

	bIdx := index + 7.

	delta := -1

    ] ifFalse:[

	bIdx := index.

	delta := 1

    ].

    1 to:8 do:[:i |

	self basicAt:bIdx put:(anInteger digitAt:i).

	bIdx := bIdx + delta.

    ].

    ^ anInteger

    "

     |b|

     b := ByteArray new:8.

     b quadWordAtIndex:1 put:16r0807060504030201 MSB:false.

     b inspect

    "

!

signedByteAt:index

    "return the byte at index as a signed 8 bit value.

     This may be worth a primitive."

    ^ (self at:index) signExtendedByteValue

    "

     |b|

     b := ByteArray new:2.

     b at:1 put:16rFF.

     b at:2 put:16r7F.

     b signedByteAt:1  

    "

    "Modified: 1.7.1996 / 21:13:53 / cg"

!

signedByteAt:index put:aSignedByteValue

    "return the byte at index as a signed 8 bit value.

     Return the signedByteValue argument.

     This may be worth a primitive."

    |b "{ Class: SmallInteger }"|

    aSignedByteValue >= 0 ifTrue:[

	b := aSignedByteValue

    ] ifFalse:[

	b := 16r100 + aSignedByteValue

    ].

    self at:index put:b.

    ^ aSignedByteValue

    "

     |b|

     b := ByteArray new:2.

     b signedByteAt:1 put:-1.

     b at:1   

    "

    "Modified: 1.7.1996 / 21:12:37 / cg"

!

signedDoubleWordAt:index

    "return the 4-bytes starting at index as a signed Integer.

     The value is retrieved in the machines natural byte order.

     This may be worth a primitive."

    |w|

    w := self doubleWordAt:index.

    (w > (16r7FFFFFFF)) ifTrue:[

	^ w - (16r100000000)

    ].

    ^ w

    "

     |b|

     b := ByteArray new:4.

     b doubleWordAt:1 put:16rFFFFFFFF.

     (b signedDoubleWordAt:1)    

    "

    "Modified: 1.7.1996 / 21:11:28 / cg"

!

signedDoubleWordAt:index MSB:msb

    "return the 4-bytes starting at index as a signed Integer.

     Depending on msb, the value is retrieved MSB-first or LSB-first.

     This may be worth a primitive."