1package utf8; 2 3$utf8::hint_bits = 0x00800000; 4 5our $VERSION = '1.21'; 6 7sub import { 8 $^H |= $utf8::hint_bits; 9} 10 11sub unimport { 12 $^H &= ~$utf8::hint_bits; 13} 14 15sub AUTOLOAD { 16 require "utf8_heavy.pl"; 17 goto &$AUTOLOAD if defined &$AUTOLOAD; 18 require Carp; 19 Carp::croak("Undefined subroutine $AUTOLOAD called"); 20} 21 221; 23__END__ 24 25=head1 NAME 26 27utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code 28 29=head1 SYNOPSIS 30 31 use utf8; 32 no utf8; 33 34 # Convert the internal representation of a Perl scalar to/from UTF-8. 35 36 $num_octets = utf8::upgrade($string); 37 $success = utf8::downgrade($string[, $fail_ok]); 38 39 # Change each character of a Perl scalar to/from a series of 40 # characters that represent the UTF-8 bytes of each original character. 41 42 utf8::encode($string); # "\x{100}" becomes "\xc4\x80" 43 utf8::decode($string); # "\xc4\x80" becomes "\x{100}" 44 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 50 $native = utf8::unicode_to_native(65); # returns 65 on ASCII 51 # platforms; 193 on 52 # EBCDIC 53 54 $flag = utf8::is_utf8($string); # since Perl 5.8.1 55 $flag = utf8::valid($string); 56 57=head1 DESCRIPTION 58 59The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the 60program text in the current lexical scope. The C<no utf8> pragma tells Perl 61to switch back to treating the source text as literal bytes in the current 62lexical scope. (On EBCDIC platforms, technically it is allowing UTF-EBCDIC, 63and not UTF-8, but this distinction is academic, so in this document the term 64UTF-8 is used to mean both). 65 66B<Do not use this pragma for anything else than telling Perl that your 67script is written in UTF-8.> The utility functions described below are 68directly usable without C<use utf8;>. 69 70Because it is not possible to reliably tell UTF-8 from native 8 bit 71encodings, you need either a Byte Order Mark at the beginning of your 72source code, or C<use utf8;>, to instruct perl. 73 74When UTF-8 becomes the standard source format, this pragma will 75effectively become a no-op. 76 77See also the effects of the C<-C> switch and its cousin, the 78C<PERL_UNICODE> environment variable, in L<perlrun>. 79 80Enabling the C<utf8> pragma has the following effect: 81 82=over 4 83 84=item * 85 86Bytes in the source text that are not in the ASCII character set will be 87treated as being part of a literal UTF-8 sequence. This includes most 88literals such as identifier names, string constants, and constant 89regular expression patterns. 90 91=back 92 93Note that if you have non-ASCII, non-UTF-8 bytes in your script (for example 94embedded Latin-1 in your string literals), C<use utf8> will be unhappy. If 95you want to have such bytes under C<use utf8>, you can disable this pragma 96until the end the block (or file, if at top level) by C<no utf8;>. 97 98=head2 Utility functions 99 100The following functions are defined in the C<utf8::> package by the 101Perl core. You do not need to say C<use utf8> to use these and in fact 102you should not say that unless you really want to have UTF-8 source code. 103 104=over 4 105 106=item * C<$num_octets = utf8::upgrade($string)> 107 108(Since Perl v5.8.0) 109Converts in-place the internal representation of the string from an octet 110sequence in the native encoding (Latin-1 or EBCDIC) to UTF-8. The 111logical character sequence itself is unchanged. If I<$string> is already 112upgraded, then this is a no-op. Returns the 113number of octets necessary to represent the string as UTF-8. 114 115If your code needs to be compatible with versions of perl without 116C<use feature 'unicode_strings';>, you can force Unicode semantics on 117a given string: 118 119 # force unicode semantics for $string without the 120 # "unicode_strings" feature 121 utf8::upgrade($string); 122 123For 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" 132 133B<Note that this function does not handle arbitrary encodings>; 134use L<Encode> instead. 135 136=item * C<$success = utf8::downgrade($string[, $fail_ok])> 137 138(Since Perl v5.8.0) 139Converts in-place the internal representation of the string from UTF-8 to the 140equivalent octet sequence in the native encoding (Latin-1 or EBCDIC). The 141logical character sequence itself is unchanged. If I<$string> is already 142stored as native 8 bit, then this is a no-op. Can be used to make sure that 143the UTF-8 flag is off, e.g. when you want to make sure that the substr() or 144length() function works with the usually faster byte algorithm. 145 146Fails if the original UTF-8 sequence cannot be represented in the 147native 8 bit encoding. On failure dies or, if the value of I<$fail_ok> is 148true, returns false. 149 150Returns true on success. 151 152If your code expects an octet sequence this can be used to validate 153that you've received one: 154 155 # throw an exception if not representable as octets 156 utf8::downgrade($string) 157 158 # or do your own error handling 159 utf8::downgrade($string, 1) or die "string must be octets"; 160 161B<Note that this function does not handle arbitrary encodings>; 162use L<Encode> instead. 163 164=item * C<utf8::encode($string)> 165 166(Since Perl v5.8.0) 167Converts in-place the character sequence to the corresponding octet 168sequence in Perl's extended UTF-8. That is, every (possibly wide) character 169gets replaced with a sequence of one or more characters that represent the 170individual UTF-8 bytes of the character. The UTF8 flag is turned off. 171Returns nothing. 172 173 my $x = "\x{100}"; # $x contains one character, with ord 0x100 174 utf8::encode($x); # $x contains two characters, with ords (on 175 # ASCII platforms) 0xc4 and 0x80. On EBCDIC 176 # 1047, this would instead be 0x8C and 0x41. 177 178Similar to: 179 180 use Encode; 181 $x = Encode::encode("utf8", $x); 182 183B<Note that this function does not handle arbitrary encodings>; 184use L<Encode> instead. 185 186=item * C<$success = utf8::decode($string)> 187 188(Since Perl v5.8.0) 189Attempts to convert in-place the octet sequence encoded in Perl's extended 190UTF-8 to the corresponding character sequence. That is, it replaces each 191sequence of characters in the string whose ords represent a valid (extended) 192UTF-8 byte sequence, with the corresponding single character. The UTF-8 flag 193is turned on only if the source string contains multiple-byte UTF-8 194characters. If I<$string> is invalid as extended UTF-8, returns false; 195otherwise returns true. 196 197 my $x = "\xc4\x80"; # $x contains two characters, with ords 198 # 0xc4 and 0x80 199 utf8::decode($x); # On ASCII platforms, $x contains one char, 200 # with ord 0x100. Since these bytes aren't 201 # legal UTF-EBCDIC, on EBCDIC platforms, $x is 202 # unchanged and the function returns FALSE. 203 204B<Note that this function does not handle arbitrary encodings>; 205use L<Encode> instead. 206 207=item * C<$unicode = utf8::native_to_unicode($code_point)> 208 209(Since Perl v5.8.0) 210This takes an unsigned integer (which represents the ordinal number of a 211character (or a code point) on the platform the program is being run on) and 212returns its Unicode equivalent value. Since ASCII platforms natively use the 213Unicode code points, this function returns its input on them. On EBCDIC 214platforms it converts from EBCDIC to Unicode. 215 216A meaningless value will currently be returned if the input is not an unsigned 217integer. 218 219Since Perl v5.22.0, calls to this function are optimized out on ASCII 220platforms, so there is no performance hit in using it there. 221 222=item * C<$native = utf8::unicode_to_native($code_point)> 223 224(Since Perl v5.8.0) 225This is the inverse of C<utf8::native_to_unicode()>, converting the other 226direction. Again, on ASCII platforms, this returns its input, but on EBCDIC 227platforms it will find the native platform code point, given any Unicode one. 228 229A meaningless value will currently be returned if the input is not an unsigned 230integer. 231 232Since Perl v5.22.0, calls to this function are optimized out on ASCII 233platforms, so there is no performance hit in using it there. 234 235=item * C<$flag = utf8::is_utf8($string)> 236 237(Since Perl 5.8.1) Test whether I<$string> is marked internally as encoded in 238UTF-8. Functionally the same as C<Encode::is_utf8($string)>. 239 240Typically only necessary for debugging and testing, if you need to 241dump the internals of an SV, L<Devel::Peek's|Devel::Peek> Dump() 242provides more detail in a compact form. 243 244If you still think you need this outside of debugging, testing or 245dealing with filenames, you should probably read L<perlunitut> and 246L<perlunifaq/What is "the UTF8 flag"?>. 247 248Don't use this flag as a marker to distinguish character and binary 249data: that should be decided for each variable when you write your 250code. 251 252To force unicode semantics in code portable to perl 5.8 and 5.10, call 253C<utf8::upgrade($string)> unconditionally. 254 255=item * C<$flag = utf8::valid($string)> 256 257[INTERNAL] Test whether I<$string> is in a consistent state regarding 258UTF-8. Will return true if it is well-formed Perl extended UTF-8 and has the 259UTF-8 flag 260on B<or> if I<$string> is held as bytes (both these states are 'consistent'). 261The main reason for this routine is to allow Perl's test suite to check 262that operations have left strings in a consistent state. 263 264=back 265 266C<utf8::encode> is like C<utf8::upgrade>, but the UTF8 flag is 267cleared. See L<perlunicode>, and the C API 268functions C<L<sv_utf8_upgrade|perlapi/sv_utf8_upgrade>>, 269C<L<perlapi/sv_utf8_downgrade>>, C<L<perlapi/sv_utf8_encode>>, 270and C<L<perlapi/sv_utf8_decode>>, which are wrapped by the Perl functions 271C<utf8::upgrade>, C<utf8::downgrade>, C<utf8::encode> and 272C<utf8::decode>. Also, the functions C<utf8::is_utf8>, C<utf8::valid>, 273C<utf8::encode>, C<utf8::decode>, C<utf8::upgrade>, and C<utf8::downgrade> are 274actually internal, and thus always available, without a C<require utf8> 275statement. 276 277=head1 BUGS 278 279Some filesystems may not support UTF-8 file names, or they may be supported 280incompatibly with Perl. Therefore UTF-8 names that are visible to the 281filesystem, such as module names may not work. 282 283=head1 SEE ALSO 284 285L<perlunitut>, L<perluniintro>, L<perlrun>, L<bytes>, L<perlunicode> 286 287=cut 288