Commit | Line | Data |
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a0ed51b3 LW |
1 | package utf8; |
2 | ||
d5448623 GS |
3 | $utf8::hint_bits = 0x00800000; |
4 | ||
ebf06983 | 5 | our $VERSION = '1.22'; |
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 { | |
daf4d4ea | 16 | goto &$AUTOLOAD if defined &$AUTOLOAD; |
bd7017d3 | 17 | require Carp; |
daf4d4ea | 18 | Carp::croak("Undefined subroutine $AUTOLOAD called"); |
a0ed51b3 LW |
19 | } |
20 | ||
21 | 1; | |
22 | __END__ | |
23 | ||
24 | =head1 NAME | |
25 | ||
b3419ed8 | 26 | utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code |
a0ed51b3 LW |
27 | |
28 | =head1 SYNOPSIS | |
29 | ||
291cc134 KW |
30 | use utf8; |
31 | no utf8; | |
a0ed51b3 | 32 | |
291cc134 | 33 | # Convert the internal representation of a Perl scalar to/from UTF-8. |
836ccc8e | 34 | |
291cc134 | 35 | $num_octets = utf8::upgrade($string); |
98695e13 | 36 | $success = utf8::downgrade($string[, $fail_ok]); |
973655a8 | 37 | |
291cc134 KW |
38 | # Change each character of a Perl scalar to/from a series of |
39 | # characters that represent the UTF-8 bytes of each original character. | |
836ccc8e | 40 | |
291cc134 KW |
41 | utf8::encode($string); # "\x{100}" becomes "\xc4\x80" |
42 | utf8::decode($string); # "\xc4\x80" becomes "\x{100}" | |
973655a8 | 43 | |
ca3d51ba KW |
44 | # Convert a code point from the platform native character set to |
45 | # Unicode, and vice-versa. | |
46 | $unicode = utf8::native_to_unicode(ord('A')); # returns 65 on both | |
47 | # ASCII and EBCDIC | |
48 | # platforms | |
a04477f8 KW |
49 | $native = utf8::unicode_to_native(65); # returns 65 on ASCII |
50 | # platforms; 193 on | |
51 | # EBCDIC | |
ca3d51ba | 52 | |
ac8b87d7 EB |
53 | $flag = utf8::is_utf8($string); # since Perl 5.8.1 |
54 | $flag = utf8::valid($string); | |
973655a8 | 55 | |
a0ed51b3 LW |
56 | =head1 DESCRIPTION |
57 | ||
393fec97 | 58 | The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the |
a04477f8 KW |
59 | program text in the current lexical scope. The C<no utf8> pragma tells Perl |
60 | to switch back to treating the source text as literal bytes in the current | |
61 | lexical scope. (On EBCDIC platforms, technically it is allowing UTF-EBCDIC, | |
62 | and not UTF-8, but this distinction is academic, so in this document the term | |
63 | UTF-8 is used to mean both). | |
a0ed51b3 | 64 | |
19b49582 JH |
65 | B<Do not use this pragma for anything else than telling Perl that your |
66 | script is written in UTF-8.> The utility functions described below are | |
2575c402 JW |
67 | directly usable without C<use utf8;>. |
68 | ||
69 | Because it is not possible to reliably tell UTF-8 from native 8 bit | |
70 | encodings, you need either a Byte Order Mark at the beginning of your | |
71 | source code, or C<use utf8;>, to instruct perl. | |
19b49582 | 72 | |
2575c402 | 73 | When UTF-8 becomes the standard source format, this pragma will |
a04477f8 | 74 | effectively become a no-op. |
a0ed51b3 | 75 | |
a74e8b45 | 76 | See also the effects of the C<-C> switch and its cousin, the |
127161e0 | 77 | C<PERL_UNICODE> environment variable, in L<perlrun>. |
a74e8b45 | 78 | |
ad0029c4 | 79 | Enabling the C<utf8> pragma has the following effect: |
a0ed51b3 | 80 | |
4ac9195f | 81 | =over 4 |
a0ed51b3 LW |
82 | |
83 | =item * | |
84 | ||
a04477f8 KW |
85 | Bytes in the source text that are not in the ASCII character set will be |
86 | treated as being part of a literal UTF-8 sequence. This includes most | |
c20e2abd | 87 | literals such as identifier names, string constants, and constant |
8f8cf39c JH |
88 | regular expression patterns. |
89 | ||
4ac9195f MS |
90 | =back |
91 | ||
a04477f8 KW |
92 | Note that if you have non-ASCII, non-UTF-8 bytes in your script (for example |
93 | embedded Latin-1 in your string literals), C<use utf8> will be unhappy. If | |
94 | you want to have such bytes under C<use utf8>, you can disable this pragma | |
95 | until the end the block (or file, if at top level) by C<no utf8;>. | |
ae90e350 | 96 | |
1b026014 NIS |
97 | =head2 Utility functions |
98 | ||
8800c35a JH |
99 | The following functions are defined in the C<utf8::> package by the |
100 | Perl core. You do not need to say C<use utf8> to use these and in fact | |
2f7e5073 | 101 | you should not say that unless you really want to have UTF-8 source code. |
1b026014 NIS |
102 | |
103 | =over 4 | |
104 | ||
308a4ae1 | 105 | =item * C<$num_octets = utf8::upgrade($string)> |
1b026014 | 106 | |
a04477f8 | 107 | (Since Perl v5.8.0) |
836ccc8e | 108 | Converts in-place the internal representation of the string from an octet |
a04477f8 | 109 | sequence in the native encoding (Latin-1 or EBCDIC) to UTF-8. The |
836ccc8e | 110 | logical character sequence itself is unchanged. If I<$string> is already |
0397beb0 TC |
111 | upgraded, then this is a no-op. Returns the |
112 | number of octets necessary to represent the string as UTF-8. | |
113 | ||
114 | If your code needs to be compatible with versions of perl without | |
115 | C<use feature 'unicode_strings';>, you can force Unicode semantics on | |
116 | a given string: | |
117 | ||
118 | # force unicode semantics for $string without the | |
119 | # "unicode_strings" feature | |
120 | utf8::upgrade($string); | |
121 | ||
122 | For example: | |
123 | ||
124 | # without explicit or implicit use feature 'unicode_strings' | |
125 | my $x = "\xDF"; # LATIN SMALL LETTER SHARP S | |
126 | $x =~ /ss/i; # won't match | |
127 | my $y = uc($x); # won't convert | |
128 | utf8::upgrade($x); | |
129 | $x =~ /ss/i; # matches | |
130 | my $z = uc($x); # converts to "SS" | |
78ea37eb | 131 | |
a04477f8 KW |
132 | B<Note that this function does not handle arbitrary encodings>; |
133 | use L<Encode> instead. | |
1b026014 | 134 | |
308a4ae1 | 135 | =item * C<$success = utf8::downgrade($string[, $fail_ok])> |
1b026014 | 136 | |
a04477f8 | 137 | (Since Perl v5.8.0) |
50a85cfe KW |
138 | Converts in-place the internal representation of the string from UTF-8 to the |
139 | equivalent octet sequence in the native encoding (Latin-1 or EBCDIC). The | |
140 | logical character sequence itself is unchanged. If I<$string> is already | |
141 | stored as native 8 bit, then this is a no-op. Can be used to make sure that | |
142 | the UTF-8 flag is off, e.g. when you want to make sure that the substr() or | |
143 | length() function works with the usually faster byte algorithm. | |
78ea37eb | 144 | |
a04477f8 | 145 | Fails if the original UTF-8 sequence cannot be represented in the |
ac8b87d7 | 146 | native 8 bit encoding. On failure dies or, if the value of I<$fail_ok> is |
2575c402 | 147 | true, returns false. |
78ea37eb | 148 | |
2575c402 JW |
149 | Returns true on success. |
150 | ||
0397beb0 TC |
151 | If your code expects an octet sequence this can be used to validate |
152 | that you've received one: | |
153 | ||
154 | # throw an exception if not representable as octets | |
155 | utf8::downgrade($string) | |
156 | ||
157 | # or do your own error handling | |
158 | utf8::downgrade($string, 1) or die "string must be octets"; | |
159 | ||
a04477f8 KW |
160 | B<Note that this function does not handle arbitrary encodings>; |
161 | use L<Encode> instead. | |
78ea37eb | 162 | |
308a4ae1 | 163 | =item * C<utf8::encode($string)> |
1b026014 | 164 | |
a04477f8 | 165 | (Since Perl v5.8.0) |
2575c402 | 166 | Converts in-place the character sequence to the corresponding octet |
50a85cfe KW |
167 | sequence in Perl's extended UTF-8. That is, every (possibly wide) character |
168 | gets replaced with a sequence of one or more characters that represent the | |
a04477f8 | 169 | individual UTF-8 bytes of the character. The UTF8 flag is turned off. |
836ccc8e DM |
170 | Returns nothing. |
171 | ||
0397beb0 TC |
172 | my $x = "\x{100}"; # $x contains one character, with ord 0x100 |
173 | utf8::encode($x); # $x contains two characters, with ords (on | |
a04477f8 KW |
174 | # ASCII platforms) 0xc4 and 0x80. On EBCDIC |
175 | # 1047, this would instead be 0x8C and 0x41. | |
78ea37eb | 176 | |
0397beb0 TC |
177 | Similar to: |
178 | ||
179 | use Encode; | |
180 | $x = Encode::encode("utf8", $x); | |
181 | ||
a04477f8 KW |
182 | B<Note that this function does not handle arbitrary encodings>; |
183 | use L<Encode> instead. | |
094ce63c | 184 | |
308a4ae1 | 185 | =item * C<$success = utf8::decode($string)> |
1b026014 | 186 | |
a04477f8 | 187 | (Since Perl v5.8.0) |
50a85cfe KW |
188 | Attempts to convert in-place the octet sequence encoded in Perl's extended |
189 | UTF-8 to the corresponding character sequence. That is, it replaces each | |
190 | sequence of characters in the string whose ords represent a valid (extended) | |
191 | UTF-8 byte sequence, with the corresponding single character. The UTF-8 flag | |
192 | is turned on only if the source string contains multiple-byte UTF-8 | |
193 | characters. If I<$string> is invalid as extended UTF-8, returns false; | |
836ccc8e DM |
194 | otherwise returns true. |
195 | ||
0397beb0 | 196 | my $x = "\xc4\x80"; # $x contains two characters, with ords |
ca3d51ba | 197 | # 0xc4 and 0x80 |
0397beb0 | 198 | utf8::decode($x); # On ASCII platforms, $x contains one char, |
a04477f8 | 199 | # with ord 0x100. Since these bytes aren't |
0397beb0 | 200 | # legal UTF-EBCDIC, on EBCDIC platforms, $x is |
a04477f8 | 201 | # unchanged and the function returns FALSE. |
78ea37eb | 202 | |
a04477f8 KW |
203 | B<Note that this function does not handle arbitrary encodings>; |
204 | use L<Encode> instead. | |
78ea37eb | 205 | |
ca3d51ba KW |
206 | =item * C<$unicode = utf8::native_to_unicode($code_point)> |
207 | ||
273e254d | 208 | (Since Perl v5.8.0) |
ca3d51ba KW |
209 | This takes an unsigned integer (which represents the ordinal number of a |
210 | character (or a code point) on the platform the program is being run on) and | |
211 | returns its Unicode equivalent value. Since ASCII platforms natively use the | |
212 | Unicode code points, this function returns its input on them. On EBCDIC | |
bc1767aa | 213 | platforms it converts from EBCDIC to Unicode. |
ca3d51ba KW |
214 | |
215 | A meaningless value will currently be returned if the input is not an unsigned | |
216 | integer. | |
217 | ||
273e254d KW |
218 | Since Perl v5.22.0, calls to this function are optimized out on ASCII |
219 | platforms, so there is no performance hit in using it there. | |
220 | ||
ca3d51ba KW |
221 | =item * C<$native = utf8::unicode_to_native($code_point)> |
222 | ||
273e254d | 223 | (Since Perl v5.8.0) |
ca3d51ba KW |
224 | This is the inverse of C<utf8::native_to_unicode()>, converting the other |
225 | direction. Again, on ASCII platforms, this returns its input, but on EBCDIC | |
226 | platforms it will find the native platform code point, given any Unicode one. | |
227 | ||
228 | A meaningless value will currently be returned if the input is not an unsigned | |
229 | integer. | |
230 | ||
273e254d KW |
231 | Since Perl v5.22.0, calls to this function are optimized out on ASCII |
232 | platforms, so there is no performance hit in using it there. | |
233 | ||
308a4ae1 | 234 | =item * C<$flag = utf8::is_utf8($string)> |
8800c35a | 235 | |
ac8b87d7 | 236 | (Since Perl 5.8.1) Test whether I<$string> is marked internally as encoded in |
0397beb0 TC |
237 | UTF-8. Functionally the same as C<Encode::is_utf8($string)>. |
238 | ||
239 | Typically only necessary for debugging and testing, if you need to | |
240 | dump the internals of an SV, L<Devel::Peek's|Devel::Peek> Dump() | |
241 | provides more detail in a compact form. | |
242 | ||
243 | If you still think you need this outside of debugging, testing or | |
244 | dealing with filenames, you should probably read L<perlunitut> and | |
245 | L<perlunifaq/What is "the UTF8 flag"?>. | |
246 | ||
247 | Don't use this flag as a marker to distinguish character and binary | |
0c50e915 | 248 | data: that should be decided for each variable when you write your |
0397beb0 TC |
249 | code. |
250 | ||
251 | To force unicode semantics in code portable to perl 5.8 and 5.10, call | |
252 | C<utf8::upgrade($string)> unconditionally. | |
8800c35a | 253 | |
308a4ae1 | 254 | =item * C<$flag = utf8::valid($string)> |
70122e76 | 255 | |
ac8b87d7 | 256 | [INTERNAL] Test whether I<$string> is in a consistent state regarding |
8b4b6c86 KW |
257 | UTF-8. Will return true if it is well-formed Perl extended UTF-8 and has the |
258 | UTF-8 flag | |
ac8b87d7 | 259 | on B<or> if I<$string> is held as bytes (both these states are 'consistent'). |
0c50e915 | 260 | The main reason for this routine is to allow Perl's test suite to check |
0397beb0 | 261 | that operations have left strings in a consistent state. |
70122e76 | 262 | |
1b026014 NIS |
263 | =back |
264 | ||
7d865a91 | 265 | C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is |
a04477f8 KW |
266 | cleared. See L<perlunicode>, and the C API |
267 | functions C<L<sv_utf8_upgrade|perlapi/sv_utf8_upgrade>>, | |
268 | C<L<perlapi/sv_utf8_downgrade>>, C<L<perlapi/sv_utf8_encode>>, | |
269 | and C<L<perlapi/sv_utf8_decode>>, which are wrapped by the Perl functions | |
094ce63c | 270 | C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and |
a04477f8 KW |
271 | C<utf8::decode>. Also, the functions C<utf8::is_utf8>, C<utf8::valid>, |
272 | C<utf8::encode>, C<utf8::decode>, C<utf8::upgrade>, and C<utf8::downgrade> are | |
7edb8f2b RGS |
273 | actually internal, and thus always available, without a C<require utf8> |
274 | statement. | |
f1e62f77 | 275 | |
8f8cf39c JH |
276 | =head1 BUGS |
277 | ||
a04477f8 KW |
278 | Some filesystems may not support UTF-8 file names, or they may be supported |
279 | incompatibly with Perl. Therefore UTF-8 names that are visible to the | |
280 | filesystem, such as module names may not work. | |
8f8cf39c | 281 | |
393fec97 | 282 | =head1 SEE ALSO |
a0ed51b3 | 283 | |
2575c402 | 284 | L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode> |
a0ed51b3 LW |
285 | |
286 | =cut |