|
|
=head1 NAME
perlebcdic - Considerations for running Perl on EBCDIC platforms
=head1 DESCRIPTION
An exploration of some of the issues facing Perl programmerson EBCDIC based computers. We do not cover localization, internationalization, or multi byte character set issues (yet).
Portions that are still incomplete are marked with XXX.
=head1 COMMON CHARACTER CODE SETS
=head2 ASCII
The American Standard Code for Information Interchange is a set ofintegers 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 integersfrom 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.
=head2 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.
=head2 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, Portugese, Spanish, and Swedish. Dutch is covered albeit without the ij ligature. French is covered too but without the oe ligature. German can use ISO 8859-1 but must do so without German-stylequotation marks. This set is based on Western European extensions to ASCII and is commonly encountered in world wide web work.In IBM character code set identification terminology ISO 8859-1 isalso known as CCSID 819 (or sometimes 0819 or even 00819).
=head2 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 theupper and lower case alphabet characters [a-z] and [A-Z], but therewere 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. Leadingzero digits in CCSID numbers within this document are insignificant.E.g. CCSID 0037 may be referred to as 37 in places.
=head2 13 variant characters
Among IBM EBCDIC character code sets there are 13 characters thatare often mapped to different integer values. Those charactersare known as the 13 "variant" characters and are:
\ [ ] { } ^ ~ ! # | $ @ `
=head2 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.
=head2 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, and OpenEdition for VM/ESA. CCSID 1047 differs from CCSID 0037 in eight places.
=head2 POSIX-BC
The EBCDIC code page in use on Siemens' BS2000 system is distinct from1047 and 0037. It is identified below as the POSIX-BC set.
=head1 SINGLE OCTET TABLES
The following tables list the ASCII and Latin 1 ordered sets includingthe 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 I<The Unicode Standard, Version 2.0> 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 C<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 translation) through:
=over 4
=item recipe 0
=back
perl -ne 'if(/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \ -e '{printf("%s%-9o%-9o%-9o%-9o\n",$1,$2,$3,$4,$5)}' perlebcdic.pod
If you would rather see this table listing hexadecimal values thenrun the table through:
=over 4
=item recipe 1
=back
perl -ne 'if(/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \ -e '{printf("%s%-9X%-9X%-9X%-9X\n",$1,$2,$3,$4,$5)}' perlebcdic.pod
8859-1 chr 0819 0037 1047 POSIX-BC ---------------------------------------------------------------- <NULL> 0 0 0 0 <START OF HEADING> 1 1 1 1 <START OF TEXT> 2 2 2 2 <END OF TEXT> 3 3 3 3 <END OF TRANSMISSION> 4 55 55 55 <ENQUIRY> 5 45 45 45 <ACKNOWLEDGE> 6 46 46 46 <BELL> 7 47 47 47 <BACKSPACE> 8 22 22 22 <HORIZONTAL TABULATION> 9 5 5 5 <LINE FEED> 10 37 21 21 *** <VERTICAL TABULATION> 11 11 11 11 <FORM FEED> 12 12 12 12 <CARRIAGE RETURN> 13 13 13 13 <SHIFT OUT> 14 14 14 14 <SHIFT IN> 15 15 15 15 <DATA LINK ESCAPE> 16 16 16 16 <DEVICE CONTROL ONE> 17 17 17 17 <DEVICE CONTROL TWO> 18 18 18 18 <DEVICE CONTROL THREE> 19 19 19 19 <DEVICE CONTROL FOUR> 20 60 60 60 <NEGATIVE ACKNOWLEDGE> 21 61 61 61 <SYNCHRONOUS IDLE> 22 50 50 50 <END OF TRANSMISSION BLOCK> 23 38 38 38 <CANCEL> 24 24 24 24 <END OF MEDIUM> 25 25 25 25 <SUBSTITUTE> 26 63 63 63 <ESCAPE> 27 39 39 39 <FILE SEPARATOR> 28 28 28 28 <GROUP SEPARATOR> 29 29 29 29 <RECORD SEPARATOR> 30 30 30 30 <UNIT SEPARATOR> 31 31 31 31 <SPACE> 32 64 64 64 ! 33 90 90 90 " 34 127 127 127 # 35 123 123 123 $ 36 91 91 91 % 37 108 108 108 & 38 80 80 80 ' 39 125 125 125 ( 40 77 77 77 ) 41 93 93 93 * 42 92 92 92 + 43 78 78 78 , 44 107 107 107 - 45 96 96 96 . 46 75 75 75 / 47 97 97 97 0 48 240 240 240 1 49 241 241 241 2 50 242 242 242 3 51 243 243 243 4 52 244 244 244 5 53 245 245 245 6 54 246 246 246 7 55 247 247 247 8 56 248 248 248 9 57 249 249 249 : 58 122 122 122 ; 59 94 94 94 < 60 76 76 76 = 61 126 126 126 > 62 110 110 110 ? 63 111 111 111 @ 64 124 124 124 A 65 193 193 193 B 66 194 194 194 C 67 195 195 195 D 68 196 196 196 E 69 197 197 197 F 70 198 198 198 G 71 199 199 199 H 72 200 200 200 I 73 201 201 201 J 74 209 209 209 K 75 210 210 210 L 76 211 211 211 M 77 212 212 212 N 78 213 213 213 O 79 214 214 214 P 80 215 215 215 Q 81 216 216 216 R 82 217 217 217 S 83 226 226 226 T 84 227 227 227 U 85 228 228 228 V 86 229 229 229 W 87 230 230 230 X 88 231 231 231 Y 89 232 232 232 Z 90 233 233 233 [ 91 186 173 187 *** ### \ 92 224 224 188 ### ] 93 187 189 189 *** ^ 94 176 95 106 *** ### _ 95 109 109 109 ` 96 121 121 74 ### a 97 129 129 129 b 98 130 130 130 c 99 131 131 131 d 100 132 132 132 e 101 133 133 133 f 102 134 134 134 g 103 135 135 135 h 104 136 136 136 i 105 137 137 137 j 106 145 145 145 k 107 146 146 146 l 108 147 147 147 m 109 148 148 148 n 110 149 149 149 o 111 150 150 150 p 112 151 151 151 q 113 152 152 152 r 114 153 153 153 s 115 162 162 162 t 116 163 163 163 u 117 164 164 164 v 118 165 165 165 w 119 166 166 166 x 120 167 167 167 y 121 168 168 168 z 122 169 169 169 { 123 192 192 251 ### | 124 79 79 79 } 125 208 208 253 ### ~ 126 161 161 255 ### <DELETE> 127 7 7 7 <C1 0> 128 32 32 32 <C1 1> 129 33 33 33 <C1 2> 130 34 34 34 <C1 3> 131 35 35 35 <C1 4> 132 36 36 36 <C1 5> 133 21 37 37 *** <C1 6> 134 6 6 6 <C1 7> 135 23 23 23 <C1 8> 136 40 40 40 <C1 9> 137 41 41 41 <C1 10> 138 42 42 42 <C1 11> 139 43 43 43 <C1 12> 140 44 44 44 <C1 13> 141 9 9 9 <C1 14> 142 10 10 10 <C1 15> 143 27 27 27 <C1 16> 144 48 48 48 <C1 17> 145 49 49 49 <C1 18> 146 26 26 26 <C1 19> 147 51 51 51 <C1 20> 148 52 52 52 <C1 21> 149 53 53 53 <C1 22> 150 54 54 54 <C1 23> 151 8 8 8 <C1 24> 152 56 56 56 <C1 25> 153 57 57 57 <C1 26> 154 58 58 58 <C1 27> 155 59 59 59 <C1 28> 156 4 4 4 <C1 29> 157 20 20 20 <C1 30> 158 62 62 62 <C1 31> 159 255 255 95 ### <NON-BREAKING SPACE> 160 65 65 65 <INVERTED EXCLAMATION MARK> 161 170 170 170 <CENT SIGN> 162 74 74 176 ### <POUND SIGN> 163 177 177 177 <CURRENCY SIGN> 164 159 159 159 <YEN SIGN> 165 178 178 178 <BROKEN BAR> 166 106 106 208 ### <SECTION SIGN> 167 181 181 181 <DIAERESIS> 168 189 187 121 *** ### <COPYRIGHT SIGN> 169 180 180 180 <FEMININE ORDINAL INDICATOR> 170 154 154 154 <LEFT POINTING GUILLEMET> 171 138 138 138 <NOT SIGN> 172 95 176 186 *** ### <SOFT HYPHEN> 173 202 202 202 <REGISTERED TRADE MARK SIGN> 174 175 175 175 <MACRON> 175 188 188 161 ### <DEGREE SIGN> 176 144 144 144 <PLUS-OR-MINUS SIGN> 177 143 143 143 <SUPERSCRIPT TWO> 178 234 234 234 <SUPERSCRIPT THREE> 179 250 250 250 <ACUTE ACCENT> 180 190 190 190 <MICRO SIGN> 181 160 160 160 <PARAGRAPH SIGN> 182 182 182 182 <MIDDLE DOT> 183 179 179 179 <CEDILLA> 184 157 157 157 <SUPERSCRIPT ONE> 185 218 218 218 <MASC. ORDINAL INDICATOR> 186 155 155 155 <RIGHT POINTING GUILLEMET> 187 139 139 139 <FRACTION ONE QUARTER> 188 183 183 183 <FRACTION ONE HALF> 189 184 184 184 <FRACTION THREE QUARTERS> 190 185 185 185 <INVERTED QUESTION MARK> 191 171 171 171 <A WITH GRAVE> 192 100 100 100 <A WITH ACUTE> 193 101 101 101 <A WITH CIRCUMFLEX> 194 98 98 98 <A WITH TILDE> 195 102 102 102 <A WITH DIAERESIS> 196 99 99 99 <A WITH RING ABOVE> 197 103 103 103 <CAPITAL LIGATURE AE> 198 158 158 158 <C WITH CEDILLA> 199 104 104 104 <E WITH GRAVE> 200 116 116 116 <E WITH ACUTE> 201 113 113 113 <E WITH CIRCUMFLEX> 202 114 114 114 <E WITH DIAERESIS> 203 115 115 115 <I WITH GRAVE> 204 120 120 120 <I WITH ACUTE> 205 117 117 117 <I WITH CIRCUMFLEX> 206 118 118 118 <I WITH DIAERESIS> 207 119 119 119 <CAPITAL LETTER ETH> 208 172 172 172 <N WITH TILDE> 209 105 105 105 <O WITH GRAVE> 210 237 237 237 <O WITH ACUTE> 211 238 238 238 <O WITH CIRCUMFLEX> 212 235 235 235 <O WITH TILDE> 213 239 239 239 <O WITH DIAERESIS> 214 236 236 236 <MULTIPLICATION SIGN> 215 191 191 191 <O WITH STROKE> 216 128 128 128 <U WITH GRAVE> 217 253 253 224 ### <U WITH ACUTE> 218 254 254 254 <U WITH CIRCUMFLEX> 219 251 251 221 ### <U WITH DIAERESIS> 220 252 252 252 <Y WITH ACUTE> 221 173 186 173 *** ### <CAPITAL LETTER THORN> 222 174 174 174 <SMALL LETTER SHARP S> 223 89 89 89 <a WITH GRAVE> 224 68 68 68 <a WITH ACUTE> 225 69 69 69 <a WITH CIRCUMFLEX> 226 66 66 66 <a WITH TILDE> 227 70 70 70 <a WITH DIAERESIS> 228 67 67 67 <a WITH RING ABOVE> 229 71 71 71 <SMALL LIGATURE ae> 230 156 156 156 <c WITH CEDILLA> 231 72 72 72 <e WITH GRAVE> 232 84 84 84 <e WITH ACUTE> 233 81 81 81 <e WITH CIRCUMFLEX> 234 82 82 82 <e WITH DIAERESIS> 235 83 83 83 <i WITH GRAVE> 236 88 88 88 <i WITH ACUTE> 237 85 85 85 <i WITH CIRCUMFLEX> 238 86 86 86 <i WITH DIAERESIS> 239 87 87 87 <SMALL LETTER eth> 240 140 140 140 <n WITH TILDE> 241 73 73 73 <o WITH GRAVE> 242 205 205 205 <o WITH ACUTE> 243 206 206 206 <o WITH CIRCUMFLEX> 244 203 203 203 <o WITH TILDE> 245 207 207 207 <o WITH DIAERESIS> 246 204 204 204 <DIVISION SIGN> 247 225 225 225 <o WITH STROKE> 248 112 112 112 <u WITH GRAVE> 249 221 221 192 ### <u WITH ACUTE> 250 222 222 222 <u WITH CIRCUMFLEX> 251 219 219 219 <u WITH DIAERESIS> 252 220 220 220 <y WITH ACUTE> 253 141 141 141 <SMALL LETTER thorn> 254 142 142 142 <y WITH DIAERESIS> 255 223 223 223
If you would rather see the above table in CCSID 0037 order rather thanASCII + Latin-1 order then run the table through:
=over 4
=item recipe 2
=back
perl -ne 'if(/.{33}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\ -e '{push(@l,$_)}' \ -e 'END{print map{$_->[0]}' \ -e ' sort{$a->[1] <=> $b->[1]}' \ -e ' map{[$_,substr($_,42,3)]}@l;}' perlebcdic.pod
If you would rather see it in CCSID 1047 order then change the digit42 in the last line to 51, like this:
=over 4
=item recipe 3
=back
perl -ne 'if(/.{33}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\ -e '{push(@l,$_)}' \ -e 'END{print map{$_->[0]}' \ -e ' sort{$a->[1] <=> $b->[1]}' \ -e ' map{[$_,substr($_,51,3)]}@l;}' perlebcdic.pod
If you would rather see it in POSIX-BC order then change the digit51 in the last line to 60, like this:
=over 4
=item recipe 4
=back
perl -ne 'if(/.{33}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\ -e '{push(@l,$_)}' \ -e 'END{print map{$_->[0]}' \ -e ' sort{$a->[1] <=> $b->[1]}' \ -e ' map{[$_,substr($_,60,3)]}@l;}' perlebcdic.pod
=head1 IDENTIFYING CHARACTER CODE SETS
To determine the character set you are running under from perl one could use the return value of ord() or chr() to test one or more character values. For example:
$is_ascii = "A" eq chr(65); $is_ebcdic = "A" eq chr(193);
Also, "\t" is a C<HORIZONTAL TABULATION> character so that:
$is_ascii = ord("\t") == 9; $is_ebcdic = ord("\t") == 5;
To distinguish EBCDIC code pages try looking at one or more ofthe characters that differ between them. For example:
$is_ebcdic_37 = "\n" eq chr(37); $is_ebcdic_1047 = "\n" eq chr(21);
Or better still choose a character that is uniquely encoded in anyof the code sets, e.g.:
$is_ascii = ord('[') == 91; $is_ebcdic_37 = ord('[') == 186; $is_ebcdic_1047 = ord('[') == 173; $is_ebcdic_POSIX_BC = ord('[') == 187;
However, it would be unwise to write tests such as:
$is_ascii = "\r" ne chr(13); # WRONG $is_ascii = "\n" ne chr(10); # ILL ADVISED
Obviously the first of these will fail to distinguish most ASCII machinesfrom either a CCSID 0037, a 1047, or a POSIX-BC EBCDIC machine since "\r" eq chr(13) under all of those coded character sets. But note too that because "\n" is chr(13) and "\r" is chr(10) on the MacIntosh (which is an ASCII machine) the second C<$is_ascii> test will lead to trouble there.
To determine whether or not perl was built under an EBCDIC code page you can use the Config module like so:
use Config; $is_ebcdic = $Config{'ebcdic'} eq 'define';
=head1 CONVERSIONS
=head2 tr///
In order to convert a string of characters from one character set to another a simple list of numbers, such as in the right columns in theabove table, along with perl's tr/// operator is all that is needed. The data in the table are in ASCII order hence the EBCDIC columns provide easy to use ASCII to EBCDIC operations that are also easily reversed.
For example, to convert ASCII to code page 037 take the output of the second column from the output of recipe 0 (modified to add \\ characters) and use it in tr/// like so:
$cp_037 = '\000\001\002\003\234\011\206\177\227\215\216\013\014\015\016\017' . '\020\021\022\023\235\205\010\207\030\031\222\217\034\035\036\037' . '\200\201\202\203\204\012\027\033\210\211\212\213\214\005\006\007' . '\220\221\026\223\224\225\226\004\230\231\232\233\024\025\236\032' . '\040\240\342\344\340\341\343\345\347\361\242\056\074\050\053\174' . '\046\351\352\353\350\355\356\357\354\337\041\044\052\051\073\254' . '\055\057\302\304\300\301\303\305\307\321\246\054\045\137\076\077' . '\370\311\312\313\310\315\316\317\314\140\072\043\100\047\075\042' . '\330\141\142\143\144\145\146\147\150\151\253\273\360\375\376\261' . '\260\152\153\154\155\156\157\160\161\162\252\272\346\270\306\244' . '\265\176\163\164\165\166\167\170\171\172\241\277\320\335\336\256' . '\136\243\245\267\251\247\266\274\275\276\133\135\257\250\264\327' . '\173\101\102\103\104\105\106\107\110\111\255\364\366\362\363\365' . '\175\112\113\114\115\116\117\120\121\122\271\373\374\371\372\377' . '\134\367\123\124\125\126\127\130\131\132\262\324\326\322\323\325' . '\060\061\062\063\064\065\066\067\070\071\263\333\334\331\332\237' ;
my $ebcdic_string = $ascii_string; eval '$ebcdic_string =~ tr/\000-\377/' . $cp_037 . '/';
To convert from EBCDIC 037 to ASCII just reverse the order of the tr/// arguments like so:
my $ascii_string = $ebcdic_string; eval '$ascii_string = tr/' . $cp_037 . '/\000-\377/';
Similarly one could take the output of the third column from recipe 0 toobtain a C<$cp_1047> table. The fourth column of the output from recipe0 could provide a C<$cp_posix_bc> table suitable for transcoding as well.
=head2 iconv
XPG operability often implies the presence of an I<iconv> utilityavailable from the shell or from the C library. Consult your system'sdocumentation for information on iconv.
On OS/390 see the iconv(1) man page. One way to invoke the iconv shell utility from within perl would be to:
# OS/390 example $ascii_data = `echo '$ebcdic_data'| iconv -f IBM-1047 -t ISO8859-1`
or the inverse map:
# OS/390 example $ebcdic_data = `echo '$ascii_data'| iconv -f ISO8859-1 -t IBM-1047`
For other perl based conversion options see the Convert::* modules on CPAN.
=head2 C RTL
The OS/390 C run time library provides _atoe() and _etoa() functions.
=head1 OPERATOR DIFFERENCES
The C<..> range operator treats certain character ranges with care on EBCDIC machines. For example the following arraywill have twenty six elements on either an EBCDIC machineor an ASCII machine:
@alphabet = ('A'..'Z'); # $#alphabet == 25
The bitwise operators such as & ^ | may return different resultswhen operating on string or character data in a perl program running on an EBCDIC machine than when run on an ASCII machine. Here isan example adapted from the one in L<perlop>:
# EBCDIC-based examples print "j p \n" ^ " a h"; # prints "JAPH\n" print "JA" | " ph\n"; # prints "japh\n" print "JAPH\nJunk" & "\277\277\277\277\277"; # prints "japh\n"; print 'p N$' ^ " E<H\n"; # prints "Perl\n";
An interesting property of the 32 C0 control charactersin the ASCII table is that they can "literally" be constructedas control characters in perl, e.g. C<(chr(0) eq "\c@")> C<(chr(1) eq "\cA")>, and so on. Perl on EBCDIC machines has been ported to take "\c@" to chr(0) and "\cA" to chr(1) as well, but thethirty three characters that result depend on which code page you areusing. The table below uses the character names from the previous table but with substitutions such as s/START OF/S.O./; s/END OF /E.O./; s/TRANSMISSION/TRANS./; s/TABULATION/TAB./; s/VERTICAL/VERT./; s/HORIZONTAL/HORIZ./; s/DEVICE CONTROL/D.C./; s/SEPARATOR/SEP./; s/NEGATIVE ACKNOWLEDGE/NEG. ACK./;. The POSIX-BC and 1047 sets areidentical throughout this range and differ from the 0037 set at only one spot (21 decimal). Note that the C<LINE FEED> charactermay be generated by "\cJ" on ASCII machines but by "\cU" on 1047 or POSIX-BC machines and cannot be generated as a C<"\c.letter."> control character on 0037 machines. Note also that "\c\\" maps to two charactersnot one.
chr ord 8859-1 0037 1047 && POSIX-BC ------------------------------------------------------------------------ "\c?" 127 <DELETE> " " ***>< "\c@" 0 <NULL> <NULL> <NULL> ***>< "\cA" 1 <S.O. HEADING> <S.O. HEADING> <S.O. HEADING> "\cB" 2 <S.O. TEXT> <S.O. TEXT> <S.O. TEXT> "\cC" 3 <E.O. TEXT> <E.O. TEXT> <E.O. TEXT> "\cD" 4 <E.O. TRANS.> <C1 28> <C1 28> "\cE" 5 <ENQUIRY> <HORIZ. TAB.> <HORIZ. TAB.> "\cF" 6 <ACKNOWLEDGE> <C1 6> <C1 6> "\cG" 7 <BELL> <DELETE> <DELETE> "\cH" 8 <BACKSPACE> <C1 23> <C1 23> "\cI" 9 <HORIZ. TAB.> <C1 13> <C1 13> "\cJ" 10 <LINE FEED> <C1 14> <C1 14> "\cK" 11 <VERT. TAB.> <VERT. TAB.> <VERT. TAB.> "\cL" 12 <FORM FEED> <FORM FEED> <FORM FEED> "\cM" 13 <CARRIAGE RETURN> <CARRIAGE RETURN> <CARRIAGE RETURN> "\cN" 14 <SHIFT OUT> <SHIFT OUT> <SHIFT OUT> "\cO" 15 <SHIFT IN> <SHIFT IN> <SHIFT IN> "\cP" 16 <DATA LINK ESCAPE> <DATA LINK ESCAPE> <DATA LINK ESCAPE> "\cQ" 17 <D.C. ONE> <D.C. ONE> <D.C. ONE> "\cR" 18 <D.C. TWO> <D.C. TWO> <D.C. TWO> "\cS" 19 <D.C. THREE> <D.C. THREE> <D.C. THREE> "\cT" 20 <D.C. FOUR> <C1 29> <C1 29> "\cU" 21 <NEG. ACK.> <C1 5> <LINE FEED> *** "\cV" 22 <SYNCHRONOUS IDLE> <BACKSPACE> <BACKSPACE> "\cW" 23 <E.O. TRANS. BLOCK> <C1 7> <C1 7> "\cX" 24 <CANCEL> <CANCEL> <CANCEL> "\cY" 25 <E.O. MEDIUM> <E.O. MEDIUM> <E.O. MEDIUM> "\cZ" 26 <SUBSTITUTE> <C1 18> <C1 18> "\c[" 27 <ESCAPE> <C1 15> <C1 15> "\c\\" 28 <FILE SEP.>\ <FILE SEP.>\ <FILE SEP.>\ "\c]" 29 <GROUP SEP.> <GROUP SEP.> <GROUP SEP.> "\c^" 30 <RECORD SEP.> <RECORD SEP.> <RECORD SEP.> ***>< "\c_" 31 <UNIT SEP.> <UNIT SEP.> <UNIT SEP.> ***><
=head1 FUNCTION DIFFERENCES
=over 8
=item chr()
chr() must be given an EBCDIC code number argument to yield a desired character return value on an EBCDIC machine. For example:
$CAPITAL_LETTER_A = chr(193);
=item ord()
ord() will return EBCDIC code number values on an EBCDIC machine.For example:
$the_number_193 = ord("A");
=item pack()
The c and C templates for pack() are dependent upon character set encoding. Examples of usage on EBCDIC include:
$foo = pack("CCCC",193,194,195,196); # $foo eq "ABCD" $foo = pack("C4",193,194,195,196); # same thing
$foo = pack("ccxxcc",193,194,195,196); # $foo eq "AB\0\0CD"
=item print()
One must be careful with scalars and strings that are passed toprint that contain ASCII encodings. One common placefor this to occur is in the output of the MIME type header forCGI script writing. For example, many perl programming guides recommend something similar to:
print "Content-type:\ttext/html\015\012\015\012"; # this may be wrong on EBCDIC
Under the IBM OS/390 USS Web Server for example you should insteadwrite that as:
print "Content-type:\ttext/html\r\n\r\n"; # OK for DGW et alia
That is because the translation from EBCDIC to ASCII is doneby the web server in this case (such code will not be appropriate forthe Macintosh however). Consult your web server's documentation for further details.
=item printf()
The formats that can convert characters to numbers and vice versawill be different from their ASCII counterparts when executedon an EBCDIC machine. Examples include:
printf("%c%c%c",193,194,195); # prints ABC
=item sort()
EBCDIC sort results may differ from ASCII sort results especially for mixed case strings. This is discussed in more detail below.
=item sprintf()
See the discussion of printf() above. An example of the useof sprintf would be:
$CAPITAL_LETTER_A = sprintf("%c",193);
=item unpack()
See the discussion of pack() above.
=back
=head1 REGULAR EXPRESSION DIFFERENCES
As of perl 5.005_03 the letter range regular expression such as [A-Z] and [a-z] have been especially coded to not pick up gap characters. For example, characters such as E<ocirc> C<o WITH CIRCUMFLEX> that lie between I and J would not be matched by the regular expression range C</[H-K]/>.
If you do want to match the alphabet gap characters in a single octet regular expression try matching the hex or octal code such as C</\313/> on EBCDIC or C</\364/> on ASCII machines to have your regular expression match C<o WITH CIRCUMFLEX>.
Another construct to be wary of is the inappropriate use of hex oroctal constants in regular expressions. Consider the followingset of subs:
sub is_c0 { my $char = substr(shift,0,1); $char =~ /[\000-\037]/; }
sub is_print_ascii { my $char = substr(shift,0,1); $char =~ /[\040-\176]/; }
sub is_delete { my $char = substr(shift,0,1); $char eq "\177"; }
sub is_c1 { my $char = substr(shift,0,1); $char =~ /[\200-\237]/; }
sub is_latin_1 { my $char = substr(shift,0,1); $char =~ /[\240-\377]/; }
The above would be adequate if the concern was only with numeric code points.However, the concern may be with characters rather than code points and on an EBCDIC machine it may be desirable for constructs such as C<if (is_print_ascii("A")) {print "A is a printable character\n";}> to printout the expected message. One way to represent the above collectionof character classification subs that is capable of working across thefour coded character sets discussed in this document is as follows:
sub Is_c0 { my $char = substr(shift,0,1); if (ord('^')==94) { # ascii return $char =~ /[\000-\037]/; } if (ord('^')==176) { # 37 return $char =~ /[\000-\003\067\055-\057\026\005\045\013-\023\074\075\062\046\030\031\077\047\034-\037]/; } if (ord('^')==95 || ord('^')==106) { # 1047 || posix-bc return $char =~ /[\000-\003\067\055-\057\026\005\025\013-\023\074\075\062\046\030\031\077\047\034-\037]/; } }
sub Is_print_ascii { my $char = substr(shift,0,1); $char =~ /[ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/; }
sub Is_delete { my $char = substr(shift,0,1); if (ord('^')==94) { # ascii return $char eq "\177"; } else { # ebcdic return $char eq "\007"; } }
sub Is_c1 { my $char = substr(shift,0,1); if (ord('^')==94) { # ascii return $char =~ /[\200-\237]/; } if (ord('^')==176) { # 37 return $char =~ /[\040-\044\025\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\377]/; } if (ord('^')==95) { # 1047 return $char =~ /[\040-\045\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\377]/; } if (ord('^')==106) { # posix-bc return $char =~ /[\040-\045\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\137]/; } }
sub Is_latin_1 { my $char = substr(shift,0,1); if (ord('^')==94) { # ascii return $char =~ /[\240-\377]/; } if (ord('^')==176) { # 37 return $char =~ /[\101\252\112\261\237\262\152\265\275\264\232\212\137\312\257\274\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\375\376\373\374\255\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\335\336\333\334\215\216\337]/; } if (ord('^')==95) { # 1047 return $char =~ /[\101\252\112\261\237\262\152\265\273\264\232\212\260\312\257\274\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\375\376\373\374\272\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\335\336\333\334\215\216\337]/; } if (ord('^')==106) { # posix-bc return $char =~ /[\101\252\260\261\237\262\320\265\171\264\232\212\272\312\257\241\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\340\376\335\374\255\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\300\336\333\334\215\216\337]/; } }
Note however that only the C<Is_ascii_print()> sub is really independent of coded character set. Another way to write C<Is_latin_1()> would be to use the characters in the range explicitly:
sub Is_latin_1 { my $char = substr(shift,0,1); $char =~ /[������������������������������������������������������������������������������������������������]/; }
Although that form may run into trouble in network transit (due to the presence of 8 bit characters) or on non ISO-Latin character sets.
=head1 SOCKETS
Most socket programming assumes ASCII character encodings in networkbyte order. Exceptions can include CGI script writing under ahost web server where the server may take care of translation for you.Most host web servers convert EBCDIC data to ISO-8859-1 or Unicode onoutput.
=head1 SORTING
One big difference between ASCII based character sets and EBCDIC onesare the relative positions of upper and lower case letters and theletters compared to the digits. If sorted on an ASCII based machine thetwo letter abbreviation for a physician comes before the two letterfor drive, that is:
@sorted = sort(qw(Dr. dr.)); # @sorted holds ('Dr.','dr.') on ASCII, # but ('dr.','Dr.') on EBCDIC
The property of lower case before uppercase letters in EBCDIC iseven carried to the Latin 1 EBCDIC pages such as 0037 and 1047.An example would be that E<Euml> C<E WITH DIAERESIS> (203) comes before E<euml> C<e WITH DIAERESIS> (235) on an ASCII machine, but the latter (83) comes before the former (115) on an EBCDIC machine. (Astute readers will note that the upper case version of E<szlig> C<SMALL LETTER SHARP S> is simply "SS" and that the upper case version of E<yuml> C<y WITH DIAERESIS> is not in the 0..255 range but it is at U+x0178 in Unicode, or C<"\x{178}"> in a Unicode enabled Perl).
The sort order will cause differences between results obtained onASCII machines versus EBCDIC machines. What follows are some suggestionson how to deal with these differences.
=head2 Ignore ASCII vs. EBCDIC sort differences.
This is the least computationally expensive strategy. It may requiresome user education.
=head2 MONO CASE then sort data.
In order to minimize the expense of mono casing mixed test try toC<tr///> towards the character set case most employed within the data.If the data are primarily UPPERCASE non Latin 1 then apply tr/[a-z]/[A-Z]/then sort(). If the data are primarily lowercase non Latin 1 thenapply tr/[A-Z]/[a-z]/ before sorting. If the data are primarily UPPERCASEand include Latin-1 characters then apply:
tr/[a-z]/[A-Z]/; tr/[������������������������������]/[������������������������������]/; s/�/SS/g;
then sort(). Do note however that such Latin-1 manipulation does not address the E<yuml> C<y WITH DIAERESIS> character that will remain at code point 255 on ASCII machines, but 223 on most EBCDIC machines where it will sort to a place less than the EBCDIC numerals. With a Unicode enabled Perl you might try:
tr/^?/\x{178}/;
The strategy of mono casing data before sorting does not preserve the case of the data and may not be acceptable for that reason.
=head2 Convert, sort data, then re convert.
This is the most expensive proposition that does not employ a networkconnection.
=head2 Perform sorting on one type of machine only.
This strategy can employ a network connection. As suchit would be computationally expensive.
=head1 TRANFORMATION FORMATS
There are a variety of ways of transforming data with an intra character set mapping that serve a variety of purposes. Sorting was discussed in the previous section and a few of the other more popular mapping techniques are discussed next.
=head2 URL decoding and encoding
Note that some URLs have hexadecimal ASCII code points in them in anattempt to overcome character or protocol limitation issues. For example the tilde character is not on every keyboard hence a URL of the form:
http://www.pvhp.com/~pvhp/
may also be expressed as either of:
http://www.pvhp.com/%7Epvhp/
http://www.pvhp.com/%7epvhp/
where 7E is the hexadecimal ASCII code point for '~'. Here is an exampleof decoding such a URL under CCSID 1047:
$url = 'http://www.pvhp.com/%7Epvhp/'; # this array assumes code page 1047 my @a2e_1047 = ( 0, 1, 2, 3, 55, 45, 46, 47, 22, 5, 21, 11, 12, 13, 14, 15, 16, 17, 18, 19, 60, 61, 50, 38, 24, 25, 63, 39, 28, 29, 30, 31, 64, 90,127,123, 91,108, 80,125, 77, 93, 92, 78,107, 96, 75, 97, 240,241,242,243,244,245,246,247,248,249,122, 94, 76,126,110,111, 124,193,194,195,196,197,198,199,200,201,209,210,211,212,213,214, 215,216,217,226,227,228,229,230,231,232,233,173,224,189, 95,109, 121,129,130,131,132,133,134,135,136,137,145,146,147,148,149,150, 151,152,153,162,163,164,165,166,167,168,169,192, 79,208,161, 7, 32, 33, 34, 35, 36, 37, 6, 23, 40, 41, 42, 43, 44, 9, 10, 27, 48, 49, 26, 51, 52, 53, 54, 8, 56, 57, 58, 59, 4, 20, 62,255, 65,170, 74,177,159,178,106,181,187,180,154,138,176,202,175,188, 144,143,234,250,190,160,182,179,157,218,155,139,183,184,185,171, 100,101, 98,102, 99,103,158,104,116,113,114,115,120,117,118,119, 172,105,237,238,235,239,236,191,128,253,254,251,252,186,174, 89, 68, 69, 66, 70, 67, 71,156, 72, 84, 81, 82, 83, 88, 85, 86, 87, 140, 73,205,206,203,207,204,225,112,221,222,219,220,141,142,223 ); $url =~ s/%([0-9a-fA-F]{2})/pack("c",$a2e_1047[hex($1)])/ge;
Conversely, here is a partial solution for the task of encoding such a URL under the 1047 code page:
$url = 'http://www.pvhp.com/~pvhp/'; # this array assumes code page 1047 my @e2a_1047 = ( 0, 1, 2, 3,156, 9,134,127,151,141,142, 11, 12, 13, 14, 15, 16, 17, 18, 19,157, 10, 8,135, 24, 25,146,143, 28, 29, 30, 31, 128,129,130,131,132,133, 23, 27,136,137,138,139,140, 5, 6, 7, 144,145, 22,147,148,149,150, 4,152,153,154,155, 20, 21,158, 26, 32,160,226,228,224,225,227,229,231,241,162, 46, 60, 40, 43,124, 38,233,234,235,232,237,238,239,236,223, 33, 36, 42, 41, 59, 94, 45, 47,194,196,192,193,195,197,199,209,166, 44, 37, 95, 62, 63, 248,201,202,203,200,205,206,207,204, 96, 58, 35, 64, 39, 61, 34, 216, 97, 98, 99,100,101,102,103,104,105,171,187,240,253,254,177, 176,106,107,108,109,110,111,112,113,114,170,186,230,184,198,164, 181,126,115,116,117,118,119,120,121,122,161,191,208, 91,222,174, 172,163,165,183,169,167,182,188,189,190,221,168,175, 93,180,215, 123, 65, 66, 67, 68, 69, 70, 71, 72, 73,173,244,246,242,243,245, 125, 74, 75, 76, 77, 78, 79, 80, 81, 82,185,251,252,249,250,255, 92,247, 83, 84, 85, 86, 87, 88, 89, 90,178,212,214,210,211,213, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,179,219,220,217,218,159 ); # The following regular expression does not address the # mappings for: ('.' => '%2E', '/' => '%2F', ':' => '%3A') $url =~ s/([\t "#%&\(\),;<=>\?\@\[\\\]^`{|}~])/sprintf("%%%02X",$e2a_1047[ord($1)])/ge;
where a more complete solution would split the URL into components and apply a full s/// substitution only to the appropriate parts.
In the remaining examples a @e2a or @a2e array may be employedbut the assignment will not be shown explicitly. For code page 1047you could use the @a2e_1047 or @e2a_1047 arrays just shown.
=head2 uu encoding and decoding
The C<u> template to pack() or unpack() will render EBCDIC data in EBCDIC characters equivalent to their ASCII counterparts. For example, the following will print "Yes indeed\n" on either an ASCII or EBCDIC computer:
$all_byte_chrs = ''; for (0..255) { $all_byte_chrs .= chr($_); } $uuencode_byte_chrs = pack('u', $all_byte_chrs); ($uu = <<' ENDOFHEREDOC') =~ s/^\s*//gm; M``$"`P0%!@<("0H+#`T.#Q`1$A,4%187&!D:&QP='A\@(2(C)"4F)R@I*BLL M+2XO,#$R,S0U-C<X.3H[/#T^/T!!0D-$149'2$E*2TQ-3D]045)35%565UA9 M6EM<75Y?8&%B8V1E9F=H:6IK;&UN;W!Q<G-T=79W>'EZ>WQ]?G^`@8*#A(6& MAXB)BHN,C8Z/D)&2DY25EI>8F9J;G)V>GZ"AHJ.DI::GJ*FJJZRMKJ^PL;*S MM+6VM[BYNKN\O;Z_P,'"P\3%QL?(R<K+S,W.S]#1TM/4U=;7V-G:V]S=WM_@ ?X>+CY.7FY^CIZNOL[>[O\/'R\_3U]O?X^?K[_/W^_P`` ENDOFHEREDOC if ($uuencode_byte_chrs eq $uu) { print "Yes "; } $uudecode_byte_chrs = unpack('u', $uuencode_byte_chrs); if ($uudecode_byte_chrs eq $all_byte_chrs) { print "indeed\n"; }
Here is a very spartan uudecoder that will work on EBCDIC providedthat the @e2a array is filled in appropriately:
#!/usr/local/bin/perl @e2a = ( # this must be filled in ); $_ = <> until ($mode,$file) = /^begin\s*(\d*)\s*(\S*)/; open(OUT, "> $file") if $file ne ""; while(<>) { last if /^end/; next if /[a-z]/; next unless int(((($e2a[ord()] - 32 ) & 077) + 2) / 3) == int(length() / 4); print OUT unpack("u", $_); } close(OUT); chmod oct($mode), $file;
=head2 Quoted-Printable encoding and decoding
On ASCII encoded machines it is possible to strip characters outside ofthe printable set using:
# This QP encoder works on ASCII only $qp_string =~ s/([=\x00-\x1F\x80-\xFF])/sprintf("=%02X",ord($1))/ge;
Whereas a QP encoder that works on both ASCII and EBCDIC machines would look somewhat like the following (where the EBCDIC branch @e2a array is omitted for brevity):
if (ord('A') == 65) { # ASCII $delete = "\x7F"; # ASCII @e2a = (0 .. 255) # ASCII to ASCII identity map } else { # EBCDIC $delete = "\x07"; # EBCDIC @e2a = # EBCDIC to ASCII map (as shown above) } $qp_string =~ s/([^ !"\#\$%&'()*+,\-.\/0-9:;<>?\@A-Z[\\\]^_`a-z{|}~$delete])/sprintf("=%02X",$e2a[ord($1)])/ge;
(although in production code the substitutions might be donein the EBCDIC branch with the @e2a array and separately in the ASCII branch without the expense of the identity map).
Such QP strings can be decoded with:
# This QP decoder is limited to ASCII only $string =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr hex $1/ge; $string =~ s/=[\n\r]+$//;
Whereas a QP decoder that works on both ASCII and EBCDIC machines would look somewhat like the following (where the @a2e array isomitted for brevity):
$string =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr $a2e[hex $1]/ge; $string =~ s/=[\n\r]+$//;
=head2 Caesarian cyphers
The practice of shifting an alphabet one or more characters for enciphermentdates back thousands of years and was explicitly detailed by Gaius JuliusCaesar in his B<Gallic Wars> text. A single alphabet shift is sometimes referred to as a rotation and the shift amount is given as a number $n afterthe string 'rot' or "rot$n". Rot0 and rot26 would designate identity maps on the 26 letter English version of the Latin alphabet. Rot13 has the interesting property that alternate subsequent invocations are identity maps (thus rot13 is its own non-trivial inverse in the group of 26 alphabet rotations). Hence the following is a rot13 encoder and decoder that will work on ASCII and EBCDIC machines:
#!/usr/local/bin/perl
while(<>){ tr/n-za-mN-ZA-M/a-zA-Z/; print; }
In one-liner form:
perl -ne 'tr/n-za-mN-ZA-M/a-zA-Z/;print'
=head1 Hashing order and checksums
XXX
=head1 I18N AND L10N
Internationalization(I18N) and localization(L10N) are supported at least in principle even on EBCDIC machines. The details are system dependent and discussed under the L<perlebcdic/OS ISSUES> section below.
=head1 MULTI OCTET CHARACTER SETS
Multi byte EBCDIC code pages; Unicode, UTF-8, UTF-EBCDIC, XXX.
=head1 OS ISSUES
There may be a few system dependent issues of concern to EBCDIC Perl programmers.
=head2 OS/400
The PASE environment.
=over 8
=item IFS access
XXX.
=back
=head2 OS/390
Perl runs under Unix Systems Services or USS.
=over 8
=item chcp
B<chcp> is supported as a shell utility for displaying and changing one's code page. See also L<chcp>.
=item dataset access
For sequential data set access try:
my @ds_records = `cat //DSNAME`;
or:
my @ds_records = `cat //'HLQ.DSNAME'`;
See also the OS390::Stdio module on CPAN.
=item OS/390 iconv
B<iconv> is supported as both a shell utility and a C RTL routine.See also the iconv(1) and iconv(3) manual pages.
=item locales
On OS/390 see L<locale> for information on locales. The L10N filesare in F</usr/nls/locale>. $Config{d_setlocale} is 'define' on OS/390.
=back
=head2 VM/ESA?
XXX.
=head2 POSIX-BC?
XXX.
=head1 BUGS
This pod document contains literal Latin 1 characters and may encounter translation difficulties. In particular one popular nroff implementation was known to strip accented characters to their unaccented counterparts while attempting to view this document through the B<pod2man> program (for example, you may see a plain C<y> rather than one with a diaeresis as in E<yuml>). Another nroff truncated the resultant man page atthe first occurence of 8 bit characters.
Not all shells will allow multiple C<-e> string arguments to perl tobe concatenated together properly as recipes 2, 3, and 4 might seemto imply.
Perl does not yet work with any Unicode features on EBCDIC platforms.
=head1 SEE ALSO
L<perllocale>, L<perlfunc>.
=head1 REFERENCES
http://anubis.dkuug.dk/i18n/charmaps
http://www.unicode.org/
http://www.unicode.org/unicode/reports/tr16/
http://www.wps.com/texts/codes/B<ASCII: American Standard Code for Information Infiltration> Tom Jennings,September 1999.
B<The Unicode Standard Version 2.0> The Unicode Consortium, ISBN 0-201-48345-9, Addison Wesley Developers Press, July 1996.
B<The Unicode Standard Version 3.0> The Unicode Consortium, Lisa Moore ed., ISBN 0-201-61633-5, Addison Wesley Developers Press, February 2000.
B<CDRA: IBM - Character Data Representation Architecture - Reference and Registry>, IBM SC09-2190-00, December 1996.
"Demystifying Character Sets", Andrea Vine, Multilingual Computing & Technology, B<#26 Vol. 10 Issue 4>, August/September 1999;ISSN 1523-0309; Multilingual Computing Inc. Sandpoint ID, USA.
B<Codes, Ciphers, and Other Cryptic and Clandestine Communication>Fred B. Wrixon, ISBN 1-57912-040-7, Black Dog & Leventhal Publishers,1998.
=head1 AUTHOR
Peter Prymmer [email protected] wrote this in 1999 and 2000 with CCSID 0819 and 0037 help from Chris Leach and AndrE<eacute> Pirard [email protected] as well as POSIX-BC help from Thomas Dorner [email protected].Thanks also to Vickie Cooper, Philip Newton, William Raffloer, and Joe Smith. Trademarks, registered trademarks, service marks and registered service marks used in this document are the property of their respective owners.
|
