"{ Encoding: utf8 }"

"
 COPYRIGHT (c) 2004 by eXept Software AG
              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.
"
"{ Package: 'stx:libbasic' }"

"{ NameSpace: CharacterEncoderImplementations }"

VariableBytesEncoder subclass:#ISO10646_to_SGML
	instanceVariableNames:''
	classVariableNames:''
	poolDictionaries:''
	category:'Collections-Text-Encodings'
!

!ISO10646_to_SGML class methodsFor:'documentation'!

copyright
"
 COPYRIGHT (c) 2004 by eXept Software AG
              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
"
    Incomplete - only knows how to encode/decode escaped decimal-code characters
    (i.e. &#nnnn; )

    TODO:
        add all other characters
        reuse this code in XML and HTML processing code.
"
! !

!ISO10646_to_SGML methodsFor:'encoding & decoding'!

decodeString:aStringOrByteCollection
    "given a string in SGML encoding (i.e. with SGML escaped characters),
     return a new string containing the same characters, in 16bit (or more) encoding.
     Returns either a normal String, a TwoByteString or a FourByteString instance.
     Only useful, when reading from external sources.
     This only handles up-to 30bit characters."

    |nBits ch 
     in out codePoint|

    nBits := 8.
    in := aStringOrByteCollection readStream.
    out := CharacterWriteStream on:(String new:10).
    [in atEnd] whileFalse:[
        ch := in next.
        ch == $& ifTrue:[
            in peekOrNil == $# ifTrue:[
                in next.
                codePoint := 0.
                [ch := in peekOrNil.
                 ch notNil and:[ch isDigit]
                ] whileTrue:[
                    codePoint := (codePoint * 10) + ch digitValue.
                    in next.
                ].
                out nextPut:(Character codePoint:codePoint).
                in peekOrNil == $; ifTrue:[
                    in next.
                ]
            ] ifFalse:[
                out nextPut:ch
            ]
        ] ifFalse:[
            out nextPut:ch
        ].
    ].
    ^ out contents

    "
     CharacterEncoderImplementations::ISO10646_to_SGML
        decodeString:'Файл' 

     CharacterEncoderImplementations::ISO10646_to_SGML
        decodeString:'#197;&bn...'
    "

    "Modified: / 17-01-2018 / 18:35:52 / stefan"
!

encodeString:aUnicodeString
    "return the SGML representation of aUnicodeString.
     The resulting string is only useful to be stored on some external file,
     not for being used inside ST/X."

    |in out|

    in := aUnicodeString readStream.
    out := WriteStream on:(String new:aUnicodeString size + 10).
    [in atEnd] whileFalse:[
        |ch codePoint|

        ch := in next.
        codePoint := ch codePoint.
        (codePoint between:16r20 and:16r7F) ifTrue:[
            out nextPut:ch.
        ] ifFalse:[
            out nextPutAll:'&#'.
            codePoint printOn:out.
            out nextPut:$;.
        ].
    ].
    ^ out contents

    "
     CharacterEncoderImplementations::ISO10646_to_SGML
        encodeString:'hello äöü' 
    "

    "Modified: / 23-10-2006 / 13:25:27 / cg"
    "Modified (format): / 17-01-2018 / 18:41:16 / stefan"
! !

!ISO10646_to_SGML methodsFor:'queries'!

characterSize:aCharacter
    |codePoint|

    codePoint := aCharacter codePoint.
    (codePoint between:16r20 and:16r7F) ifTrue:[
        ^ 1.
    ].
    ^ codePoint printString size + 3   "#&1234;"

    "Created: / 17-01-2018 / 18:01:40 / stefan"
! !

!ISO10646_to_SGML methodsFor:'stream support'!

readNextCharacterFrom:aStream
    |char codePoint|

    char := aStream next.
    (char ~~ $# and:[aStream peek ~~ $&]) ifTrue:[
        ^ char.
    ].
    aStream next.

    codePoint := 0.
    [char := aStream peekOrNil.
     char notNil and:[char isDigit]
    ] whileTrue:[
        codePoint := (codePoint * 10) + char digitValue.
        aStream next.
    ].
    aStream peekOrNil == $; ifTrue:[
        aStream next.
    ].
    ^ Character codePoint:codePoint.

    "Created: / 17-01-2018 / 18:37:40 / stefan"
! !

!ISO10646_to_SGML class methodsFor:'documentation'!

version
    ^ '$Header$'
! !