"{ Package: 'stx:libbasic2' }"

Object subclass:#PrintfScanf

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'System-Support'

!

!PrintfScanf class methodsFor:'documentation'!

documentation

"   

    Contributed by Jan Steinman donated to the

    community in 1989.

    Provided AS-IS - no warranty, use at your own risk.

    Original comment:

        NAME            printf-scanf

        AUTHOR          Jan Steinman <jans@tekgvs.labs.tek.com>

        FUNCTION        printf and scanf for Smalltalk

        ST-VERSIONS     Tek 2.2.2a 4.0

        PREREQUISITES   CharacterComparing

        CONFLICTS       

        DISTRIBUTION    world

        VERSION         1.1

        DATE            Apr 1989?

        SUMMARY 

    The following methods implement printf and scanf functionality.  They

    are intended to be used to ease porting between Smalltalk and C, and

    for facilitating machine-machine communication.  They are not at all

    intended as replacements for Smalltalk's printOn: functionality.

    Jan Steinman - N7JDB

    Tektronix Electronic Systems Laboratory

    Box 500, MS 50-370, Beaverton, OR 97077

    (w)503/627-5881 (h)503/657-7703

"

!

examples

"

    self new printf:'%#x %#X %03o%*.*s' arguments: #(16rABCD 16rEF 5 9 5 ''ghijklmn'') 

    self new printf:'%- 10.4s%.2e' arguments: (Array with: 'abcdefghijkl' with: Float pi)  

    self new printf:'%8.3f' arguments: (Array with: 200 sqrt negated)

    self new printf:'%c' arguments: #(16r41) 

    self new printf:'%c' arguments: #( $A )  

    self new printf:'%s' arguments: #( $A )  

    self new printf:'%s' arguments: #( 'hello' )   

    self new printf:'%4s' arguments: #( 'hello' )   

    self new printf:'%7s' arguments: #( 'hello' )   

    self new sscanf:'%f%2s%s%s%s' string: '237.0 this is a test' 

    self new sscanf:'%d%f%s' fromString: '25 54.32e-01 monday'

    self new sscanf:'%f%*f %8[A-F0-9]%c%d 0x%x%f' fromString: '12.45 1048.73 AE40Z527 0x75BCD15 34' 

    '%#x %#X %03o%*.*s' printf: #(16rABCD 16rEF 5 9 5 ''ghijklmn'') 

    '%- 10.4s%.2e' printf: (Array with: 'abcdefghijkl' with: Float pi)  

    '%8.3f' printf: (Array with: 200 sqrt negated)

    '%c' printf: #(16r41)

    '%f%2s%s%s%s' sscanf: '237.0 this is a test' 

    '%d%f%s' sscanf: '25 54.32e-01 monday'

    '%f%*f %8[A-F0-9]%c%d 0x%x%f' sscanf: '12.45 1048.73 AE40Z527 0x75BCD15 34'

"

! !

!PrintfScanf class methodsFor:'others'!

version_CVS

! !

!

     formatted in C style, as described in the UTek manual page for

     printf(3).  This method is designed for producing output

     suitable for a machine."     

! !

absDecimalPrintFloat:aFloat on:aStream digits:digits 

    "Place a string representation of the receiver on <aStream> using <digits> significant digits, using decimal notation."

    |exp x fuzz i|

    "x is myself normalized to (1.0, 10.0), exp is my exponent"

    exp := aFloat abs < 1.0 ifTrue:[

                (10.0 / aFloat abs) log floor negated

            ] ifFalse:[

                aFloat abs log floor

            ].

    x := aFloat abs / (10.0 raisedTo:exp).

    fuzz := 10.0 raisedTo:1 - digits.

    x := 0.5 * fuzz + x.

    x >= 10.0 ifTrue:[ 

        "check if rounding has unnormalized x" 

        x := x / 10.0.

        exp := exp + 1

    ].

    exp < 0 ifTrue:[

        1 to:1 - exp do:[:j | 

            aStream nextPut:('0.000000000000' at:j)

        ]

    ].

    [ x >= fuzz ] whileTrue:[ 

        "use fuzz to track significance" 

        i := x truncated.

        aStream nextPut:(48 + i) asCharacter.

        x := (x - i) * 10.0.

        fuzz := fuzz * 10.0.

        exp := exp - 1.

        exp = -1 ifTrue:[

            aStream nextPut:$.

        ]

    ].

    [ exp >= -1 ] whileTrue:[

        aStream nextPut:$0.

        exp := exp - 1.

        exp = -1 ifTrue:[

            aStream nextPut:$.

        ]

    ]

!

absPrintFloat:aFloat on:aStream digits:digits 

    "Place a string representation of the receiver on <aStream> using <digits> significant digits."

    (aFloat < 1.0e6 and:[ aFloat > 1.0e-4 ]) ifTrue:[

        self 

            absDecimalPrintFloat:aFloat

            on:aStream

            digits:digits

    ] ifFalse:[

        aFloat 

            absScientificPrintFloat:aFloat

            on:aStream

            digits:digits

    ]

!

absScientificPrintFloat:aFloat on:aStream digits:digits 

    "Place a string representation of the receiver on <aStream> using <digits> significant digits, using scientific notation."

    |exp fuzz x q i|

    "x is myself normalized to [1.0, 10.0), exp is my exponent"

    exp := aFloat abs < 1.0 ifTrue:[

                (10.0 / aFloat abs) log floor negated

            ] ifFalse:[

                aFloat abs log floor

            ].

    x := aFloat abs / (10.0 raisedTo:exp).

    fuzz := 10.0 raisedTo:1 - digits.

    x := 0.5 * fuzz + x.

    x >= 10.0 ifTrue:[ "check if rounding has unnormalized x" 

        x := x / 10.0.

        exp := exp + 1

    ].

    q := exp.

    exp := 0.

    [ x >= fuzz ] whileTrue:[

        "use fuzz to track significance" 

        i := x truncated.

        aStream nextPut:(48 + i) asCharacter.

        x := (x - i) * 10.0.

        fuzz := fuzz * 10.0.

        exp := exp - 1.

        exp = -1 ifTrue:[

            aStream nextPut:$.

        ]

    ].

    [ exp >= -1 ] whileTrue:[

        aStream nextPut:$0.

        exp := exp - 1.

        exp = -1 ifTrue:[

            aStream nextPut:$.

        ]

    ].

    aStream nextPut:$e.

    q printOn:aStream

!

formatArgCountFor:aFormatString

    "Return the number of arguments required/produced,

     if the argument is interpreted as a printf/scanf format control string."

    |nonConsecutive count|

    nonConsecutive := true.

    count := 0.

    aFormatString do:[:c |

        c == $% ifTrue:[

            nonConsecutive ifTrue:[

                count := count + 1. 

                nonConsecutive := false

            ] ifFalse:[

                count := count - 1. 

                nonConsecutive := true

            ]

        ] ifFalse:[

            nonConsecutive := true

        ]

    ].

    ^ count

! !

!PrintfScanf methodsFor:'scanning'!

scanArgFrom:dataStream to:collection format:format 

    "Add to <collection> an object who's representation is found

     in <dataStream> interpreted according to the conversion

     control string in the Stream <format>.  <format> is assumed to

     be positioned just past a $%, and a complete control string is

     assumed available.    

     Return when the conversion control string is consumed.  Leave

     <format> pointing past the last character in the conversion

     control string, leave <dataStream> pointing past any width

     specified in <format>, or at the first character that doesn't

     make sense for the <format>."

    |final width char pos data scanset exclusive return last|

    final := [:retval | 

            collection add:retval.

            data == dataStream ifFalse:[

                dataStream position:dataStream position + data position

            ].

            ^ self

        ].

    char := format peek.

    char == $% ifTrue:[

        ^ dataStream peekFor:char

    ].

    char == $* ifTrue:[

        format next.

        char := format peek.

        final := [:retval | 

                data == dataStream ifFalse:[

                    dataStream position:dataStream position + data position

                ].

                ^ self

            ]

    ].

    width := 0.

    char isDigit ifTrue:[

        width := Integer readFrom:format.

        char := format peek

    ].

    ('slhduoxfeg' includes:char) ifTrue:[

        dataStream skipSeparators

    ].

    width = 0 ifTrue:[

        data := dataStream

    ] ifFalse:[

        pos := dataStream position.

        data := ReadStream on:(dataStream next:width).

        dataStream position:pos

    ].

    char == $s ifTrue:[

        final value:(data upToSeparator)

    ].

    char == $c ifTrue:[

        width = 0 ifTrue:[

            final value:(String with:data next)

        ] ifFalse:[