"
    Module:  	AKG-FILESTREAM.ST
    Author:  	A. Grant
    Date:    	28-Oct-1990
    Version:	2.00-00
    Modified:	3-Nov-1990

Index:

nextLine
			Answer a String consisting of the characters
			of the receiver up to the next line delimiter.

vmsFileName: aString
			Answer a String which is a valid VMS filename which is 
			made up of the best guess from aString.

"
"
|     Change Log
| ============================================================================
| Author       Date       Change 
| ALISTAIR   19 Nov 90	  Version 2.00
|			  Added vmsFileName: selector.
|
"


!FileStream class methodsFor: 'File Names'!

vmsFileName: aString

| name type pos |

  "Break the file name up into its name and type components."

  pos := aString indexOf: $..
  (pos = 0) ifTrue: "Whole string is the name"
    [
      name := aString.
      type := String new: 0.
    ]
  ifFalse:
    [
      name := aString copyFrom: 1 to: (pos - 1).
      type := aString copyFrom: (pos + 1) to: (aString size).
    ].

  "Scan the file name for invalid characters."
  pos := 1.
  name do:
    [ :char |
      (FileStream validVMSChar: char) ifFalse:
      	[
      	  name at: pos put: $_.
      	].
      pos := pos + 1.
    ].

  "First character of a filename may not be a -"
  ((name at: 1) = $-) ifTrue:
    [name at: 1 put: $_].

  "Scan the file type for invalid characters."
  pos := 1.
  type do:
    [ :char |
      (FileStream validVMSChar: char) ifFalse:
      	[
      	  type at: pos put: $_.
      	].
      pos := pos + 1.
    ].

  "The last character of the file type may not be a -"
  pos := type size.
  (pos > 0) ifTrue:
    [
      ((type at: pos) = $-) ifTrue:
      	[type at: pos put: $_]
    ].

  "Return the resulting file name"
  ^(name, '.', type)
!


validVMSChar: aCharacter

  "Return true if aCharacter is a valid file name character"

  (aCharacter isDigit) ifTrue:
    [^true].

  (aCharacter isLetter) ifTrue:
    [^true].

  (#($_ $- $$) includes: aCharacter) ifTrue:
    [^true].

  ^false

!!


!FileStream methodsFor: 'basic'!

nextLine
    "Read characters until an end of line is reached."

| lineString thisChar |

    lineString _ ''.

    [(((thisChar _ self next) asciiValue) = 10) or: [self atEnd]]
    	whileFalse:
    	    [lineString := lineString copyWith: thisChar].
    ^lineString
!!