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a0ed51b3 LW |
1 | package utf8; |
2 | ||
d5448623 GS |
3 | $utf8::hint_bits = 0x00800000; |
4 | ||
0397beb0 | 5 | our $VERSION = '1.20'; |
b75c8c73 | 6 | |
a0ed51b3 | 7 | sub import { |
d5448623 | 8 | $^H |= $utf8::hint_bits; |
a0ed51b3 LW |
9 | } |
10 | ||
11 | sub unimport { | |
d5448623 | 12 | $^H &= ~$utf8::hint_bits; |
a0ed51b3 LW |
13 | } |
14 | ||
15 | sub AUTOLOAD { | |
16 | require "utf8_heavy.pl"; | |
daf4d4ea | 17 | goto &$AUTOLOAD if defined &$AUTOLOAD; |
bd7017d3 | 18 | require Carp; |
daf4d4ea | 19 | Carp::croak("Undefined subroutine $AUTOLOAD called"); |
a0ed51b3 LW |
20 | } |
21 | ||
22 | 1; | |
23 | __END__ | |
24 | ||
25 | =head1 NAME | |
26 | ||
b3419ed8 | 27 | utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code |
a0ed51b3 LW |
28 | |
29 | =head1 SYNOPSIS | |
30 | ||
291cc134 KW |
31 | use utf8; |
32 | no utf8; | |
a0ed51b3 | 33 | |
291cc134 | 34 | # Convert the internal representation of a Perl scalar to/from UTF-8. |
836ccc8e | 35 | |
291cc134 | 36 | $num_octets = utf8::upgrade($string); |
98695e13 | 37 | $success = utf8::downgrade($string[, $fail_ok]); |
973655a8 | 38 | |
291cc134 KW |
39 | # Change each character of a Perl scalar to/from a series of |
40 | # characters that represent the UTF-8 bytes of each original character. | |
836ccc8e | 41 | |
291cc134 KW |
42 | utf8::encode($string); # "\x{100}" becomes "\xc4\x80" |
43 | utf8::decode($string); # "\xc4\x80" becomes "\x{100}" | |
973655a8 | 44 | |
ca3d51ba KW |
45 | # Convert a code point from the platform native character set to |
46 | # Unicode, and vice-versa. | |
47 | $unicode = utf8::native_to_unicode(ord('A')); # returns 65 on both | |
48 | # ASCII and EBCDIC | |
49 | # platforms | |
a04477f8 KW |
50 | $native = utf8::unicode_to_native(65); # returns 65 on ASCII |
51 | # platforms; 193 on | |
52 | # EBCDIC | |
ca3d51ba | 53 | |
ac8b87d7 EB |
54 | $flag = utf8::is_utf8($string); # since Perl 5.8.1 |
55 | $flag = utf8::valid($string); | |
973655a8 | 56 | |
a0ed51b3 LW |
57 | =head1 DESCRIPTION |
58 | ||
393fec97 | 59 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the |
a04477f8 KW |
60 | program text in the current lexical scope. The C<no utf8> pragma tells Perl |
61 | to switch back to treating the source text as literal bytes in the current | |
62 | lexical scope. (On EBCDIC platforms, technically it is allowing UTF-EBCDIC, | |
63 | and not UTF-8, but this distinction is academic, so in this document the term | |
64 | UTF-8 is used to mean both). | |
a0ed51b3 | 65 | |
19b49582 JH |
66 | B<Do not use this pragma for anything else than telling Perl that your |
67 | script is written in UTF-8.> The utility functions described below are | |
2575c402 JW |
68 | directly usable without C<use utf8;>. |
69 | ||
70 | Because it is not possible to reliably tell UTF-8 from native 8 bit | |
71 | encodings, you need either a Byte Order Mark at the beginning of your | |
72 | source code, or C<use utf8;>, to instruct perl. | |
19b49582 | 73 | |
2575c402 | 74 | When UTF-8 becomes the standard source format, this pragma will |
a04477f8 | 75 | effectively become a no-op. |
a0ed51b3 | 76 | |
a74e8b45 | 77 | See also the effects of the C<-C> switch and its cousin, the |
127161e0 | 78 | C<PERL_UNICODE> environment variable, in L<perlrun>. |
a74e8b45 | 79 | |
ad0029c4 | 80 | Enabling the C<utf8> pragma has the following effect: |
a0ed51b3 | 81 | |
4ac9195f | 82 | =over 4 |
a0ed51b3 LW |
83 | |
84 | =item * | |
85 | ||
a04477f8 KW |
86 | Bytes in the source text that are not in the ASCII character set will be |
87 | treated as being part of a literal UTF-8 sequence. This includes most | |
c20e2abd | 88 | literals such as identifier names, string constants, and constant |
8f8cf39c JH |
89 | regular expression patterns. |
90 | ||
4ac9195f MS |
91 | =back |
92 | ||
a04477f8 KW |
93 | Note that if you have non-ASCII, non-UTF-8 bytes in your script (for example |
94 | embedded Latin-1 in your string literals), C<use utf8> will be unhappy. If | |
95 | you want to have such bytes under C<use utf8>, you can disable this pragma | |
96 | until the end the block (or file, if at top level) by C<no utf8;>. | |
ae90e350 | 97 | |
1b026014 NIS |
98 | =head2 Utility functions |
99 | ||
8800c35a JH |
100 | The following functions are defined in the C<utf8::> package by the |
101 | Perl core. You do not need to say C<use utf8> to use these and in fact | |
2f7e5073 | 102 | you should not say that unless you really want to have UTF-8 source code. |
1b026014 NIS |
103 | |
104 | =over 4 | |
105 | ||
308a4ae1 | 106 | =item * C<$num_octets = utf8::upgrade($string)> |
1b026014 | 107 | |
a04477f8 | 108 | (Since Perl v5.8.0) |
836ccc8e | 109 | Converts in-place the internal representation of the string from an octet |
a04477f8 | 110 | sequence in the native encoding (Latin-1 or EBCDIC) to UTF-8. The |
836ccc8e | 111 | logical character sequence itself is unchanged. If I<$string> is already |
0397beb0 TC |
112 | upgraded, then this is a no-op. Returns the |
113 | number of octets necessary to represent the string as UTF-8. | |
114 | ||
115 | If your code needs to be compatible with versions of perl without | |
116 | C<use feature 'unicode_strings';>, you can force Unicode semantics on | |
117 | a given string: | |
118 | ||
119 | # force unicode semantics for $string without the | |
120 | # "unicode_strings" feature | |
121 | utf8::upgrade($string); | |
122 | ||
123 | For example: | |
124 | ||
125 | # without explicit or implicit use feature 'unicode_strings' | |
126 | my $x = "\xDF"; # LATIN SMALL LETTER SHARP S | |
127 | $x =~ /ss/i; # won't match | |
128 | my $y = uc($x); # won't convert | |
129 | utf8::upgrade($x); | |
130 | $x =~ /ss/i; # matches | |
131 | my $z = uc($x); # converts to "SS" | |
78ea37eb | 132 | |
a04477f8 KW |
133 | B<Note that this function does not handle arbitrary encodings>; |
134 | use L<Encode> instead. | |
1b026014 | 135 | |
308a4ae1 | 136 | =item * C<$success = utf8::downgrade($string[, $fail_ok])> |
1b026014 | 137 | |
a04477f8 | 138 | (Since Perl v5.8.0) |
730d7228 | 139 | Converts in-place the internal representation of the string from |
a04477f8 | 140 | UTF-8 to the equivalent octet sequence in the native encoding (Latin-1 |
836ccc8e DM |
141 | or EBCDIC). The logical character sequence itself is unchanged. If |
142 | I<$string> is already stored as native 8 bit, then this is a no-op. Can | |
143 | be used to | |
2575c402 JW |
144 | make sure that the UTF-8 flag is off, e.g. when you want to make sure |
145 | that the substr() or length() function works with the usually faster | |
146 | byte algorithm. | |
78ea37eb | 147 | |
a04477f8 | 148 | Fails if the original UTF-8 sequence cannot be represented in the |
ac8b87d7 | 149 | native 8 bit encoding. On failure dies or, if the value of I<$fail_ok> is |
2575c402 | 150 | true, returns false. |
78ea37eb | 151 | |
2575c402 JW |
152 | Returns true on success. |
153 | ||
0397beb0 TC |
154 | If your code expects an octet sequence this can be used to validate |
155 | that you've received one: | |
156 | ||
157 | # throw an exception if not representable as octets | |
158 | utf8::downgrade($string) | |
159 | ||
160 | # or do your own error handling | |
161 | utf8::downgrade($string, 1) or die "string must be octets"; | |
162 | ||
a04477f8 KW |
163 | B<Note that this function does not handle arbitrary encodings>; |
164 | use L<Encode> instead. | |
78ea37eb | 165 | |
308a4ae1 | 166 | =item * C<utf8::encode($string)> |
1b026014 | 167 | |
a04477f8 | 168 | (Since Perl v5.8.0) |
2575c402 | 169 | Converts in-place the character sequence to the corresponding octet |
a04477f8 | 170 | sequence in UTF-8. That is, every (possibly wide) character gets |
836ccc8e | 171 | replaced with a sequence of one or more characters that represent the |
a04477f8 | 172 | individual UTF-8 bytes of the character. The UTF8 flag is turned off. |
836ccc8e DM |
173 | Returns nothing. |
174 | ||
0397beb0 TC |
175 | my $x = "\x{100}"; # $x contains one character, with ord 0x100 |
176 | utf8::encode($x); # $x contains two characters, with ords (on | |
a04477f8 KW |
177 | # ASCII platforms) 0xc4 and 0x80. On EBCDIC |
178 | # 1047, this would instead be 0x8C and 0x41. | |
78ea37eb | 179 | |
0397beb0 TC |
180 | Similar to: |
181 | ||
182 | use Encode; | |
183 | $x = Encode::encode("utf8", $x); | |
184 | ||
a04477f8 KW |
185 | B<Note that this function does not handle arbitrary encodings>; |
186 | use L<Encode> instead. | |
094ce63c | 187 | |
308a4ae1 | 188 | =item * C<$success = utf8::decode($string)> |
1b026014 | 189 | |
a04477f8 KW |
190 | (Since Perl v5.8.0) |
191 | Attempts to convert in-place the octet sequence encoded as UTF-8 to the | |
836ccc8e | 192 | corresponding character sequence. That is, it replaces each sequence of |
a04477f8 | 193 | characters in the string whose ords represent a valid UTF-8 byte |
836ccc8e | 194 | sequence, with the corresponding single character. The UTF-8 flag is |
a04477f8 KW |
195 | turned on only if the source string contains multiple-byte UTF-8 |
196 | characters. If I<$string> is invalid as UTF-8, returns false; | |
836ccc8e DM |
197 | otherwise returns true. |
198 | ||
0397beb0 | 199 | my $x = "\xc4\x80"; # $x contains two characters, with ords |
ca3d51ba | 200 | # 0xc4 and 0x80 |
0397beb0 | 201 | utf8::decode($x); # On ASCII platforms, $x contains one char, |
a04477f8 | 202 | # with ord 0x100. Since these bytes aren't |
0397beb0 | 203 | # legal UTF-EBCDIC, on EBCDIC platforms, $x is |
a04477f8 | 204 | # unchanged and the function returns FALSE. |
78ea37eb | 205 | |
a04477f8 KW |
206 | B<Note that this function does not handle arbitrary encodings>; |
207 | use L<Encode> instead. | |
78ea37eb | 208 | |
ca3d51ba KW |
209 | =item * C<$unicode = utf8::native_to_unicode($code_point)> |
210 | ||
273e254d | 211 | (Since Perl v5.8.0) |
ca3d51ba KW |
212 | This takes an unsigned integer (which represents the ordinal number of a |
213 | character (or a code point) on the platform the program is being run on) and | |
214 | returns its Unicode equivalent value. Since ASCII platforms natively use the | |
215 | Unicode code points, this function returns its input on them. On EBCDIC | |
bc1767aa | 216 | platforms it converts from EBCDIC to Unicode. |
ca3d51ba KW |
217 | |
218 | A meaningless value will currently be returned if the input is not an unsigned | |
219 | integer. | |
220 | ||
273e254d KW |
221 | Since Perl v5.22.0, calls to this function are optimized out on ASCII |
222 | platforms, so there is no performance hit in using it there. | |
223 | ||
ca3d51ba KW |
224 | =item * C<$native = utf8::unicode_to_native($code_point)> |
225 | ||
273e254d | 226 | (Since Perl v5.8.0) |
ca3d51ba KW |
227 | This is the inverse of C<utf8::native_to_unicode()>, converting the other |
228 | direction. Again, on ASCII platforms, this returns its input, but on EBCDIC | |
229 | platforms it will find the native platform code point, given any Unicode one. | |
230 | ||
231 | A meaningless value will currently be returned if the input is not an unsigned | |
232 | integer. | |
233 | ||
273e254d KW |
234 | Since Perl v5.22.0, calls to this function are optimized out on ASCII |
235 | platforms, so there is no performance hit in using it there. | |
236 | ||
308a4ae1 | 237 | =item * C<$flag = utf8::is_utf8($string)> |
8800c35a | 238 | |
ac8b87d7 | 239 | (Since Perl 5.8.1) Test whether I<$string> is marked internally as encoded in |
0397beb0 TC |
240 | UTF-8. Functionally the same as C<Encode::is_utf8($string)>. |
241 | ||
242 | Typically only necessary for debugging and testing, if you need to | |
243 | dump the internals of an SV, L<Devel::Peek's|Devel::Peek> Dump() | |
244 | provides more detail in a compact form. | |
245 | ||
246 | If you still think you need this outside of debugging, testing or | |
247 | dealing with filenames, you should probably read L<perlunitut> and | |
248 | L<perlunifaq/What is "the UTF8 flag"?>. | |
249 | ||
250 | Don't use this flag as a marker to distinguish character and binary | |
251 | data, that should be decided for each variable when you write your | |
252 | code. | |
253 | ||
254 | To force unicode semantics in code portable to perl 5.8 and 5.10, call | |
255 | C<utf8::upgrade($string)> unconditionally. | |
8800c35a | 256 | |
308a4ae1 | 257 | =item * C<$flag = utf8::valid($string)> |
70122e76 | 258 | |
ac8b87d7 | 259 | [INTERNAL] Test whether I<$string> is in a consistent state regarding |
9a54da5c | 260 | UTF-8. Will return true if it is well-formed UTF-8 and has the UTF-8 flag |
ac8b87d7 | 261 | on B<or> if I<$string> is held as bytes (both these states are 'consistent'). |
637ec54e | 262 | Main reason for this routine is to allow Perl's test suite to check |
0397beb0 | 263 | that operations have left strings in a consistent state. |
70122e76 | 264 | |
1b026014 NIS |
265 | =back |
266 | ||
7d865a91 | 267 | C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is |
a04477f8 KW |
268 | cleared. See L<perlunicode>, and the C API |
269 | functions C<L<sv_utf8_upgrade|perlapi/sv_utf8_upgrade>>, | |
270 | C<L<perlapi/sv_utf8_downgrade>>, C<L<perlapi/sv_utf8_encode>>, | |
271 | and C<L<perlapi/sv_utf8_decode>>, which are wrapped by the Perl functions | |
094ce63c | 272 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and |
a04477f8 KW |
273 | C<utf8::decode>. Also, the functions C<utf8::is_utf8>, C<utf8::valid>, |
274 | C<utf8::encode>, C<utf8::decode>, C<utf8::upgrade>, and C<utf8::downgrade> are | |
7edb8f2b RGS |
275 | actually internal, and thus always available, without a C<require utf8> |
276 | statement. | |
f1e62f77 | 277 | |
8f8cf39c JH |
278 | =head1 BUGS |
279 | ||
a04477f8 KW |
280 | Some filesystems may not support UTF-8 file names, or they may be supported |
281 | incompatibly with Perl. Therefore UTF-8 names that are visible to the | |
282 | filesystem, such as module names may not work. | |
8f8cf39c | 283 | |
393fec97 | 284 | =head1 SEE ALSO |
a0ed51b3 | 285 | |
2575c402 | 286 | L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode> |
a0ed51b3 LW |
287 | |
288 | =cut |