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PERLEBCDIC(1) Perl Programmers Reference Guide PERLEBCDIC(1)
NAME
perlebcdic - Considerations for running Perl on EBCDIC
platforms
DESCRIPTION
An exploration of some of the issues facing Perl program-
mers on EBCDIC based computers. We do not cover localiza-
tion, internationalization, or multi byte character set
issues other than some discussion of UTF-8 and UTF-EBCDIC.
Portions that are still incomplete are marked with XXX.
COMMON CHARACTER CODE SETS
ASCII
The American Standard Code for Information Interchange is
a set of integers running from 0 to 127 (decimal) that
imply character interpretation by the display and other
system(s) of computers. The range 0..127 can be covered
by setting the bits in a 7-bit binary digit, hence the set
is sometimes referred to as a "7-bit ASCII". ASCII was
described by the American National Standards Institute
document ANSI X3.4-1986. It was also described by ISO
646:1991 (with localization for currency symbols). The
full ASCII set is given in the table below as the first
128 elements. Languages that can be written adequately
with the characters in ASCII include English, Hawaiian,
Indonesian, Swahili and some Native American languages.
There are many character sets that extend the range of
integers from 0..2**7-1 up to 2**8-1, or 8 bit bytes
(octets if you prefer). One common one is the ISO 8859-1
character set.
ISO 8859
The ISO 8859-$n are a collection of character code sets
from the International Organization for Standardization
(ISO) each of which adds characters to the ASCII set that
are typically found in European languages many of which
are based on the Roman, or Latin, alphabet.
Latin 1 (ISO 8859-1)
A particular 8-bit extension to ASCII that includes grave
and acute accented Latin characters. Languages that can
employ ISO 8859-1 include all the languages covered by
ASCII as well as Afrikaans, Albanian, Basque, Catalan,
Danish, Faroese, Finnish, Norwegian, Portuguese, Spanish,
and Swedish. Dutch is covered albeit without the ij liga-
ture. French is covered too but without the oe ligature.
German can use ISO 8859-1 but must do so without German-
style quotation marks. This set is based on Western Euro-
pean extensions to ASCII and is commonly encountered in
world wide web work. In IBM character code set identifi-
cation terminology ISO 8859-1 is also known as CCSID 819
(or sometimes 0819 or even 00819).
EBCDIC
The Extended Binary Coded Decimal Interchange Code refers
to a large collection of slightly different single and
multi byte coded character sets that are different from
ASCII or ISO 8859-1 and typically run on host computers.
The EBCDIC encodings derive from 8 bit byte extensions of
Hollerith punched card encodings. The layout on the cards
was such that high bits were set for the upper and lower
case alphabet characters [a-z] and [A-Z], but there were
gaps within each latin alphabet range.
Some IBM EBCDIC character sets may be known by character
code set identification numbers (CCSID numbers) or code
page numbers. Leading zero digits in CCSID numbers within
this document are insignificant. E.g. CCSID 0037 may be
referred to as 37 in places.
13 variant characters
Among IBM EBCDIC character code sets there are 13 charac-
ters that are often mapped to different integer values.
Those characters are known as the 13 "variant" characters
and are:
\ [ ] { } ^ ~ ! # | $ @ `
0037
Character code set ID 0037 is a mapping of the ASCII plus
Latin-1 characters (i.e. ISO 8859-1) to an EBCDIC set.
0037 is used in North American English locales on the
OS/400 operating system that runs on AS/400 computers.
CCSID 37 differs from ISO 8859-1 in 237 places, in other
words they agree on only 19 code point values.
1047
Character code set ID 1047 is also a mapping of the ASCII
plus Latin-1 characters (i.e. ISO 8859-1) to an EBCDIC
set. 1047 is used under Unix System Services for OS/390
or z/OS, and OpenEdition for VM/ESA. CCSID 1047 differs
from CCSID 0037 in eight places.
POSIX-BC
The EBCDIC code page in use on Siemens' BS2000 system is
distinct from 1047 and 0037. It is identified below as
the POSIX-BC set.
Unicode code points versus EBCDIC code points
In Unicode terminology a code point is the number assigned
to a character: for example, in EBCDIC the character "A"
is usually assigned the number 193. In Unicode the char-
acter "A" is assigned the number 65. This causes a prob-
lem with the semantics of the pack/unpack "U", which are
supposed to pack Unicode code points to characters and
back to numbers. The problem is: which code points to use
for code points less than 256? (for 256 and over there's
no problem: Unicode code points are used) In EBCDIC, for
the low 256 the EBCDIC code points are used. This means
that the equivalences
pack("U", ord($character)) eq $character
unpack("U", $character) == ord $character
will hold. (If Unicode code points were applied consis-
tently over all the possible code points,
pack("U",ord("A")) would in EBCDIC equal A with acute or
chr(101), and unpack("U", "A") would equal 65, or non-
breaking space, not 193, or ord "A".)
Remaining Perl Unicode problems in EBCDIC
o Many of the remaining seem to be related to case-
insensitive matching: for example, "/[\x{131}]/"
(LATIN SMALL LETTER DOTLESS I) does not match "I"
case-insensitively, as it should under Unicode. (The
match succeeds in ASCII-derived platforms.)
o The extensions Unicode::Collate and Unicode::Normal-
ized are not supported under EBCDIC, likewise for the
encoding pragma.
Unicode and UTF
UTF is a Unicode Transformation Format. UTF-8 is a Uni-
code conforming representation of the Unicode standard
that looks very much like ASCII. UTF-EBCDIC is an attempt
to represent Unicode characters in an EBCDIC transparent
manner.
Using Encode
Starting from Perl 5.8 you can use the standard new module
Encode to translate from EBCDIC to Latin-1 code points
use Encode 'from_to';
my %ebcdic = ( 176 => 'cp37', 95 => 'cp1047', 106 => 'posix-bc' );
# $a is in EBCDIC code points
from_to($a, $ebcdic{ord '^'}, 'latin1');
# $a is ISO 8859-1 code points
and from Latin-1 code points to EBCDIC code points
use Encode 'from_to';
my %ebcdic = ( 176 => 'cp37', 95 => 'cp1047', 106 => 'posix-bc' );
# $a is ISO 8859-1 code points
from_to($a, 'latin1', $ebcdic{ord '^'});
# $a is in EBCDIC code points
For doing I/O it is suggested that you use the autotrans-
lating features of PerlIO, see perluniintro.
Since version 5.8 Perl uses the new PerlIO I/O library.
This enables you to use different encodings per IO chan-
nel. For example you may use
use Encode;
open($f, ">:encoding(ascii)", "test.ascii");
print $f "Hello World!\n";
open($f, ">:encoding(cp37)", "test.ebcdic");
print $f "Hello World!\n";
open($f, ">:encoding(latin1)", "test.latin1");
print $f "Hello World!\n";
open($f, ">:encoding(utf8)", "test.utf8");
print $f "Hello World!\n";
to get two files containing "Hello World!\n" in ASCII, CP
37 EBCDIC, ISO 8859-1 (Latin-1) (in this example identical
to ASCII) respective UTF-EBCDIC (in this example identical
to normal EBCDIC). See the documentation of Encode::Per-
lIO for details.
As the PerlIO layer uses raw IO (bytes) internally, all
this totally ignores things like the type of your filesys-
tem (ASCII or EBCDIC).
SINGLE OCTET TABLES
The following tables list the ASCII and Latin 1 ordered
sets including the subsets: C0 controls (0..31), ASCII
graphics (32..7e), delete (7f), C1 controls (80..9f), and
Latin-1 (a.k.a. ISO 8859-1) (a0..ff). In the table non-
printing control character names as well as the Latin 1
extensions to ASCII have been labelled with character
names roughly corresponding to The Unicode Standard, Ver-
sion 3.0 albeit with substitutions such as s/LATIN// and
s/VULGAR// in all cases, s/CAPITAL LETTER// in some cases,
and s/SMALL LETTER ([A-Z])/\l$1/ in some other cases (the
"charnames" pragma names unfortunately do not list
explicit names for the C0 or C1 control characters). The
"names" of the C1 control set (128..159 in ISO 8859-1)
listed here are somewhat arbitrary. The differences
between the 0037 and 1047 sets are flagged with ***. The
differences between the 1047 and POSIX-BC sets are flagged
with ###. All ord() numbers listed are decimal. If you
would rather see this table listing octal values then run
the table (that is, the pod version of this document since
this recipe may not work with a pod2_other_format transla-
tion) through:
recipe 0
perl -ne 'if(/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
-e '{printf("%s%-9o%-9o%-9o%o\n",$1,$2,$3,$4,$5)}' perlebcdic.pod
If you want to retain the UTF-x code points then in script
form you might want to write:
recipe 1
open(FH,") {
if (/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/) {
if ($7 ne '' && $9 ne '') {
printf("%s%-9o%-9o%-9o%-9o%-3o.%-5o%-3o.%o\n",$1,$2,$3,$4,$5,$6,$7,$8,$9);
}
elsif ($7 ne '') {
printf("%s%-9o%-9o%-9o%-9o%-3o.%-5o%o\n",$1,$2,$3,$4,$5,$6,$7,$8);
}
else {
printf("%s%-9o%-9o%-9o%-9o%-9o%o\n",$1,$2,$3,$4,$5,$6,$8);
}
}
}
If you would rather see this table listing hexadecimal
values then run the table through:
recipe 2
perl -ne 'if(/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
-e '{printf("%s%-9X%-9X%-9X%X\n",$1,$2,$3,$4,$5)}' perlebcdic.pod
Or, in order to retain the UTF-x code points in hexadeci-
mal:
recipe 3
open(FH,") {
if (/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/) {
if ($7 ne '' && $9 ne '') {
printf("%s%-9X%-9X%-9X%-9X%-2X.%-6X%-2X.%X\n",$1,$2,$3,$4,$5,$6,$7,$8,$9);
}
elsif ($7 ne '') {
printf("%s%-9X%-9X%-9X%-9X%-2X.%-6X%X\n",$1,$2,$3,$4,$5,$6,$7,$8);
}
else {
printf("%s%-9X%-9X%-9X%-9X%-9X%X\n",$1,$2,$3,$4,$5,$6,$8);
}
}
}
incomp- incomp-
8859-1 lete lete
chr 0819 0037 1047 POSIX-BC UTF-8 UTF-EBCDIC
------------------------------------------------------------------------------------
0 0 0 0 0 0
1 1 1 1 1 1
2 2 2 2 2 2
3 3 3 3 3 3
4 55 55 55 4 55
5 45 45 45 5 45
6 46 46 46 6 46
7 47 47 47 7 47
8 22 22 22 8 22
9 5 5 5 9 5
10 37 21 21 10 21 ***
11 11 11 11 11 11