Summary

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	File:     ebcdic.icn

	Subject:  Procedures to convert between ASCII and EBCDIC

	Author:   Alan Beale

	Date:     August 14, 1996

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   This file is in the public domain.

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     These procedures assist in use of the ASCII and EBCDIC character sets,
     regardless of the native character set of the host:

     Ascii128()    Returns a 128-byte string of ASCII characters in
                   numerical order.  Ascii128() should be used in
                   preference to &ascii for applications which might
                   run on an EBCDIC host.

     Ascii256()    Returns a 256-byte string representing the 256-
                   character ASCII character set.  On an EBCDIC host,
                   the order of the second 128 characters is essentially
                   arbitrary.

     Ebcdic()      Returns a 256-byte string of EBCDIC characters in
                   numerical order.

     AsciiChar(i)  Returns the character whose ASCII representation is i.

     AsciiOrd(c)   Returns the position of the character c in the ASCII
                   collating sequence.

     EbcdicChar(i) Returns the character whose EBCDIC representation is i.

     EbcdicOrd(c)  Returns the position of the character c in the EBCDIC
                   collating sequence.

     MapEtoA(s)    Maps a string of EBCDIC characters to the equivalent
                   ASCII string, according to a plausible mapping.

     MapAtoE(s)    Maps a string of ASCII characters to the equivalent
                   EBCDIC string, according to a plausible mapping.

     Control(c)    Returns the "control character" associated with the
                   character c.  On an EBCDIC host, with $ representing
                   an EBCDIC character with no 7-bit ASCII equivalent,
                   Control("$") may not be identical to "\^$", as
                   translated by ICONT (and neither result is particularly
                   meaningful).

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   Notes:

       There is no universally accepted mapping between ASCII and EBCDIC.
       See the SHARE Inc. publication "ASCII and EBCDIC Character Set and
       Code Issues in Systems Application Architecture" for more information
       than you would ever want to have on this subject.

       The mapping of the first 128 characters defined below by Ascii128()
       is the most commonly accepted mapping, even though it probably
       is not exactly like the mapping used by your favorite PC to mainframe
       file transfer utility.  The mapping of the second 128 characters
       is quite arbitrary, except that where an alternate translation of
       ASCII char(n) is popular, this translation is assigned to
       Ascii256()[n+129].

       The behavior of all functions in this package is controlled solely
       by the string literals in the _Eascii() procedure.  Therefore you
       may modify these strings to taste, and still obtain consistent
       results, provided that each character appears exactly once in the
       result of _Eascii().

       Yes, it's really true that the EBCDIC "\n" (NL, char(16r15)) is not
       the same as "\l" (LF, char(16r25)).  How can that be?  "Don't blame
       me, man, I didn't do it."

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This file is part of the (main) package.

Ascii128()

Ascii256()

AsciiChar(i)

AsciiOrd(c)

Control(c)

Ebcdic()

EbcdicChar(i)

EbcdicOrd(c)

MapAtoE(s)

MapEtoA(s)

_Eascii()