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a0ed51b3 LW |
1 | package utf8; |
2 | ||
ba6f05db TR |
3 | use strict; |
4 | use warnings; | |
d5448623 | 5 | |
ba6f05db TR |
6 | our $hint_bits = 0x00800000; |
7 | ||
347a477c | 8 | our $VERSION = '1.25'; |
ba6f05db | 9 | our $AUTOLOAD; |
b75c8c73 | 10 | |
a0ed51b3 | 11 | sub import { |
ba6f05db | 12 | $^H |= $hint_bits; |
a0ed51b3 LW |
13 | } |
14 | ||
15 | sub unimport { | |
ba6f05db | 16 | $^H &= ~$hint_bits; |
a0ed51b3 LW |
17 | } |
18 | ||
19 | sub AUTOLOAD { | |
daf4d4ea | 20 | goto &$AUTOLOAD if defined &$AUTOLOAD; |
bd7017d3 | 21 | require Carp; |
daf4d4ea | 22 | Carp::croak("Undefined subroutine $AUTOLOAD called"); |
a0ed51b3 LW |
23 | } |
24 | ||
25 | 1; | |
26 | __END__ | |
27 | ||
28 | =head1 NAME | |
29 | ||
b3419ed8 | 30 | utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code |
a0ed51b3 LW |
31 | |
32 | =head1 SYNOPSIS | |
33 | ||
291cc134 KW |
34 | use utf8; |
35 | no utf8; | |
a0ed51b3 | 36 | |
291cc134 | 37 | # Convert the internal representation of a Perl scalar to/from UTF-8. |
836ccc8e | 38 | |
291cc134 | 39 | $num_octets = utf8::upgrade($string); |
98695e13 | 40 | $success = utf8::downgrade($string[, $fail_ok]); |
973655a8 | 41 | |
291cc134 KW |
42 | # Change each character of a Perl scalar to/from a series of |
43 | # characters that represent the UTF-8 bytes of each original character. | |
836ccc8e | 44 | |
291cc134 KW |
45 | utf8::encode($string); # "\x{100}" becomes "\xc4\x80" |
46 | utf8::decode($string); # "\xc4\x80" becomes "\x{100}" | |
973655a8 | 47 | |
ca3d51ba KW |
48 | # Convert a code point from the platform native character set to |
49 | # Unicode, and vice-versa. | |
50 | $unicode = utf8::native_to_unicode(ord('A')); # returns 65 on both | |
51 | # ASCII and EBCDIC | |
52 | # platforms | |
a04477f8 KW |
53 | $native = utf8::unicode_to_native(65); # returns 65 on ASCII |
54 | # platforms; 193 on | |
55 | # EBCDIC | |
ca3d51ba | 56 | |
ac8b87d7 EB |
57 | $flag = utf8::is_utf8($string); # since Perl 5.8.1 |
58 | $flag = utf8::valid($string); | |
973655a8 | 59 | |
a0ed51b3 LW |
60 | =head1 DESCRIPTION |
61 | ||
393fec97 | 62 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the |
a04477f8 KW |
63 | program text in the current lexical scope. The C<no utf8> pragma tells Perl |
64 | to switch back to treating the source text as literal bytes in the current | |
65 | lexical scope. (On EBCDIC platforms, technically it is allowing UTF-EBCDIC, | |
66 | and not UTF-8, but this distinction is academic, so in this document the term | |
67 | UTF-8 is used to mean both). | |
a0ed51b3 | 68 | |
19b49582 JH |
69 | B<Do not use this pragma for anything else than telling Perl that your |
70 | script is written in UTF-8.> The utility functions described below are | |
2575c402 JW |
71 | directly usable without C<use utf8;>. |
72 | ||
73 | Because it is not possible to reliably tell UTF-8 from native 8 bit | |
74 | encodings, you need either a Byte Order Mark at the beginning of your | |
75 | source code, or C<use utf8;>, to instruct perl. | |
19b49582 | 76 | |
2575c402 | 77 | When UTF-8 becomes the standard source format, this pragma will |
a04477f8 | 78 | effectively become a no-op. |
a0ed51b3 | 79 | |
a74e8b45 | 80 | See also the effects of the C<-C> switch and its cousin, the |
127161e0 | 81 | C<PERL_UNICODE> environment variable, in L<perlrun>. |
a74e8b45 | 82 | |
ad0029c4 | 83 | Enabling the C<utf8> pragma has the following effect: |
a0ed51b3 | 84 | |
4ac9195f | 85 | =over 4 |
a0ed51b3 LW |
86 | |
87 | =item * | |
88 | ||
a04477f8 KW |
89 | Bytes in the source text that are not in the ASCII character set will be |
90 | treated as being part of a literal UTF-8 sequence. This includes most | |
c20e2abd | 91 | literals such as identifier names, string constants, and constant |
8f8cf39c JH |
92 | regular expression patterns. |
93 | ||
4ac9195f MS |
94 | =back |
95 | ||
a04477f8 KW |
96 | Note that if you have non-ASCII, non-UTF-8 bytes in your script (for example |
97 | embedded Latin-1 in your string literals), C<use utf8> will be unhappy. If | |
98 | you want to have such bytes under C<use utf8>, you can disable this pragma | |
99 | until the end the block (or file, if at top level) by C<no utf8;>. | |
ae90e350 | 100 | |
1b026014 NIS |
101 | =head2 Utility functions |
102 | ||
8800c35a JH |
103 | The following functions are defined in the C<utf8::> package by the |
104 | Perl core. You do not need to say C<use utf8> to use these and in fact | |
2f7e5073 | 105 | you should not say that unless you really want to have UTF-8 source code. |
1b026014 NIS |
106 | |
107 | =over 4 | |
108 | ||
308a4ae1 | 109 | =item * C<$num_octets = utf8::upgrade($string)> |
1b026014 | 110 | |
a04477f8 | 111 | (Since Perl v5.8.0) |
836ccc8e | 112 | Converts in-place the internal representation of the string from an octet |
a04477f8 | 113 | sequence in the native encoding (Latin-1 or EBCDIC) to UTF-8. The |
836ccc8e | 114 | logical character sequence itself is unchanged. If I<$string> is already |
0397beb0 TC |
115 | upgraded, then this is a no-op. Returns the |
116 | number of octets necessary to represent the string as UTF-8. | |
347a477c KW |
117 | Since Perl v5.38, if C<$string> is C<undef> no action is taken; prior to that, |
118 | it would be converted to be defined and zero-length. | |
0397beb0 TC |
119 | |
120 | If your code needs to be compatible with versions of perl without | |
121 | C<use feature 'unicode_strings';>, you can force Unicode semantics on | |
122 | a given string: | |
123 | ||
124 | # force unicode semantics for $string without the | |
125 | # "unicode_strings" feature | |
126 | utf8::upgrade($string); | |
127 | ||
128 | For example: | |
129 | ||
130 | # without explicit or implicit use feature 'unicode_strings' | |
131 | my $x = "\xDF"; # LATIN SMALL LETTER SHARP S | |
132 | $x =~ /ss/i; # won't match | |
133 | my $y = uc($x); # won't convert | |
134 | utf8::upgrade($x); | |
135 | $x =~ /ss/i; # matches | |
136 | my $z = uc($x); # converts to "SS" | |
78ea37eb | 137 | |
a04477f8 KW |
138 | B<Note that this function does not handle arbitrary encodings>; |
139 | use L<Encode> instead. | |
1b026014 | 140 | |
308a4ae1 | 141 | =item * C<$success = utf8::downgrade($string[, $fail_ok])> |
1b026014 | 142 | |
a04477f8 | 143 | (Since Perl v5.8.0) |
50a85cfe KW |
144 | Converts in-place the internal representation of the string from UTF-8 to the |
145 | equivalent octet sequence in the native encoding (Latin-1 or EBCDIC). The | |
146 | logical character sequence itself is unchanged. If I<$string> is already | |
147 | stored as native 8 bit, then this is a no-op. Can be used to make sure that | |
148 | the UTF-8 flag is off, e.g. when you want to make sure that the substr() or | |
149 | length() function works with the usually faster byte algorithm. | |
78ea37eb | 150 | |
a04477f8 | 151 | Fails if the original UTF-8 sequence cannot be represented in the |
ac8b87d7 | 152 | native 8 bit encoding. On failure dies or, if the value of I<$fail_ok> is |
2575c402 | 153 | true, returns false. |
78ea37eb | 154 | |
2575c402 JW |
155 | Returns true on success. |
156 | ||
0397beb0 TC |
157 | If your code expects an octet sequence this can be used to validate |
158 | that you've received one: | |
159 | ||
160 | # throw an exception if not representable as octets | |
161 | utf8::downgrade($string) | |
162 | ||
163 | # or do your own error handling | |
164 | utf8::downgrade($string, 1) or die "string must be octets"; | |
165 | ||
a04477f8 KW |
166 | B<Note that this function does not handle arbitrary encodings>; |
167 | use L<Encode> instead. | |
78ea37eb | 168 | |
308a4ae1 | 169 | =item * C<utf8::encode($string)> |
1b026014 | 170 | |
a04477f8 | 171 | (Since Perl v5.8.0) |
2575c402 | 172 | Converts in-place the character sequence to the corresponding octet |
50a85cfe KW |
173 | sequence in Perl's extended UTF-8. That is, every (possibly wide) character |
174 | gets replaced with a sequence of one or more characters that represent the | |
a04477f8 | 175 | individual UTF-8 bytes of the character. The UTF8 flag is turned off. |
836ccc8e DM |
176 | Returns nothing. |
177 | ||
0397beb0 TC |
178 | my $x = "\x{100}"; # $x contains one character, with ord 0x100 |
179 | utf8::encode($x); # $x contains two characters, with ords (on | |
a04477f8 KW |
180 | # ASCII platforms) 0xc4 and 0x80. On EBCDIC |
181 | # 1047, this would instead be 0x8C and 0x41. | |
78ea37eb | 182 | |
0397beb0 TC |
183 | Similar to: |
184 | ||
185 | use Encode; | |
186 | $x = Encode::encode("utf8", $x); | |
187 | ||
a04477f8 KW |
188 | B<Note that this function does not handle arbitrary encodings>; |
189 | use L<Encode> instead. | |
094ce63c | 190 | |
308a4ae1 | 191 | =item * C<$success = utf8::decode($string)> |
1b026014 | 192 | |
a04477f8 | 193 | (Since Perl v5.8.0) |
50a85cfe KW |
194 | Attempts to convert in-place the octet sequence encoded in Perl's extended |
195 | UTF-8 to the corresponding character sequence. That is, it replaces each | |
196 | sequence of characters in the string whose ords represent a valid (extended) | |
197 | UTF-8 byte sequence, with the corresponding single character. The UTF-8 flag | |
198 | is turned on only if the source string contains multiple-byte UTF-8 | |
199 | characters. If I<$string> is invalid as extended UTF-8, returns false; | |
836ccc8e DM |
200 | otherwise returns true. |
201 | ||
0397beb0 | 202 | my $x = "\xc4\x80"; # $x contains two characters, with ords |
ca3d51ba | 203 | # 0xc4 and 0x80 |
0397beb0 | 204 | utf8::decode($x); # On ASCII platforms, $x contains one char, |
a04477f8 | 205 | # with ord 0x100. Since these bytes aren't |
0397beb0 | 206 | # legal UTF-EBCDIC, on EBCDIC platforms, $x is |
a04477f8 | 207 | # unchanged and the function returns FALSE. |
089cd0e7 KW |
208 | my $y = "\xc3\x83\xc2\xab"; This has been encoded twice; this |
209 | # example is only for ASCII platforms | |
210 | utf8::decode($y); # Converts $y to \xc3\xab, returns TRUE; | |
211 | utf8::decode($y); # Further converts to \xeb, returns TRUE; | |
212 | utf8::decode($y); # Returns FALSE, leaves $y unchanged | |
78ea37eb | 213 | |
a04477f8 KW |
214 | B<Note that this function does not handle arbitrary encodings>; |
215 | use L<Encode> instead. | |
78ea37eb | 216 | |
ca3d51ba KW |
217 | =item * C<$unicode = utf8::native_to_unicode($code_point)> |
218 | ||
273e254d | 219 | (Since Perl v5.8.0) |
ca3d51ba KW |
220 | This takes an unsigned integer (which represents the ordinal number of a |
221 | character (or a code point) on the platform the program is being run on) and | |
222 | returns its Unicode equivalent value. Since ASCII platforms natively use the | |
223 | Unicode code points, this function returns its input on them. On EBCDIC | |
bc1767aa | 224 | platforms it converts from EBCDIC to Unicode. |
ca3d51ba KW |
225 | |
226 | A meaningless value will currently be returned if the input is not an unsigned | |
227 | integer. | |
228 | ||
273e254d KW |
229 | Since Perl v5.22.0, calls to this function are optimized out on ASCII |
230 | platforms, so there is no performance hit in using it there. | |
231 | ||
ca3d51ba KW |
232 | =item * C<$native = utf8::unicode_to_native($code_point)> |
233 | ||
273e254d | 234 | (Since Perl v5.8.0) |
ca3d51ba KW |
235 | This is the inverse of C<utf8::native_to_unicode()>, converting the other |
236 | direction. Again, on ASCII platforms, this returns its input, but on EBCDIC | |
237 | platforms it will find the native platform code point, given any Unicode one. | |
238 | ||
239 | A meaningless value will currently be returned if the input is not an unsigned | |
240 | integer. | |
241 | ||
273e254d KW |
242 | Since Perl v5.22.0, calls to this function are optimized out on ASCII |
243 | platforms, so there is no performance hit in using it there. | |
244 | ||
308a4ae1 | 245 | =item * C<$flag = utf8::is_utf8($string)> |
8800c35a | 246 | |
ac8b87d7 | 247 | (Since Perl 5.8.1) Test whether I<$string> is marked internally as encoded in |
0397beb0 TC |
248 | UTF-8. Functionally the same as C<Encode::is_utf8($string)>. |
249 | ||
250 | Typically only necessary for debugging and testing, if you need to | |
251 | dump the internals of an SV, L<Devel::Peek's|Devel::Peek> Dump() | |
252 | provides more detail in a compact form. | |
253 | ||
254 | If you still think you need this outside of debugging, testing or | |
255 | dealing with filenames, you should probably read L<perlunitut> and | |
256 | L<perlunifaq/What is "the UTF8 flag"?>. | |
257 | ||
258 | Don't use this flag as a marker to distinguish character and binary | |
0c50e915 | 259 | data: that should be decided for each variable when you write your |
0397beb0 TC |
260 | code. |
261 | ||
262 | To force unicode semantics in code portable to perl 5.8 and 5.10, call | |
263 | C<utf8::upgrade($string)> unconditionally. | |
8800c35a | 264 | |
308a4ae1 | 265 | =item * C<$flag = utf8::valid($string)> |
70122e76 | 266 | |
ac8b87d7 | 267 | [INTERNAL] Test whether I<$string> is in a consistent state regarding |
8b4b6c86 KW |
268 | UTF-8. Will return true if it is well-formed Perl extended UTF-8 and has the |
269 | UTF-8 flag | |
ac8b87d7 | 270 | on B<or> if I<$string> is held as bytes (both these states are 'consistent'). |
0c50e915 | 271 | The main reason for this routine is to allow Perl's test suite to check |
0397beb0 | 272 | that operations have left strings in a consistent state. |
70122e76 | 273 | |
1b026014 NIS |
274 | =back |
275 | ||
7d865a91 | 276 | C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is |
a04477f8 KW |
277 | cleared. See L<perlunicode>, and the C API |
278 | functions C<L<sv_utf8_upgrade|perlapi/sv_utf8_upgrade>>, | |
279 | C<L<perlapi/sv_utf8_downgrade>>, C<L<perlapi/sv_utf8_encode>>, | |
280 | and C<L<perlapi/sv_utf8_decode>>, which are wrapped by the Perl functions | |
094ce63c | 281 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and |
a04477f8 KW |
282 | C<utf8::decode>. Also, the functions C<utf8::is_utf8>, C<utf8::valid>, |
283 | C<utf8::encode>, C<utf8::decode>, C<utf8::upgrade>, and C<utf8::downgrade> are | |
7edb8f2b RGS |
284 | actually internal, and thus always available, without a C<require utf8> |
285 | statement. | |
f1e62f77 | 286 | |
8f8cf39c JH |
287 | =head1 BUGS |
288 | ||
a04477f8 KW |
289 | Some filesystems may not support UTF-8 file names, or they may be supported |
290 | incompatibly with Perl. Therefore UTF-8 names that are visible to the | |
291 | filesystem, such as module names may not work. | |
8f8cf39c | 292 | |
393fec97 | 293 | =head1 SEE ALSO |
a0ed51b3 | 294 | |
2575c402 | 295 | L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode> |
a0ed51b3 LW |
296 | |
297 | =cut |