| File | /usr/local/lib/perl/5.10.0/Encode/Encoding.pm |
| Statements Executed | 12 |
| Total Time | 0.0005711 seconds |
| Calls | P | F | Exclusive Time |
Inclusive Time |
Subroutine |
|---|---|---|---|---|---|
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::BEGIN |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::DEBUG |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::DESTROY |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::Define |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::decode |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::encode |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::fromUnicode |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::mime_name |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::name |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::needs_lines |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::perlio_ok |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::renew |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::renewed |
| 0 | 0 | 0 | 0s | 0s | Encode::Encoding::toUnicode |
| Line | Stmts. | Exclusive Time | Avg. | Code |
|---|---|---|---|---|
| 1 | package Encode::Encoding; | |||
| 2 | ||||
| 3 | # Base class for classes which implement encodings | |||
| 4 | 3 | 25µs | 8µs | use strict; # spent 8µs making 1 call to strict::import |
| 5 | 3 | 519µs | 173µs | use warnings; # spent 32µs making 1 call to warnings::import |
| 6 | 3 | 18µs | 6µs | our $VERSION = do { my @r = ( q$Revision: 2.5 $ =~ /\d+/g ); sprintf "%d." . "%02d" x $#r, @r }; |
| 7 | ||||
| 8 | 1 | 600ns | 600ns | require Encode; |
| 9 | ||||
| 10 | sub DEBUG { 0 } | |||
| 11 | ||||
| 12 | sub Define { | |||
| 13 | my $obj = shift; | |||
| 14 | my $canonical = shift; | |||
| 15 | $obj = bless { Name => $canonical }, $obj unless ref $obj; | |||
| 16 | ||||
| 17 | # warn "$canonical => $obj\n"; | |||
| 18 | Encode::define_encoding( $obj, $canonical, @_ ); | |||
| 19 | } | |||
| 20 | ||||
| 21 | sub name { return shift->{'Name'} } | |||
| 22 | ||||
| 23 | sub mime_name{ | |||
| 24 | require Encode::MIME::Name; | |||
| 25 | return Encode::MIME::Name::get_mime_name(shift->name); | |||
| 26 | } | |||
| 27 | ||||
| 28 | # sub renew { return $_[0] } | |||
| 29 | ||||
| 30 | sub renew { | |||
| 31 | my $self = shift; | |||
| 32 | my $clone = bless {%$self} => ref($self); | |||
| 33 | $clone->{renewed}++; # so the caller can see it | |||
| 34 | DEBUG and warn $clone->{renewed}; | |||
| 35 | return $clone; | |||
| 36 | } | |||
| 37 | ||||
| 38 | sub renewed { return $_[0]->{renewed} || 0 } | |||
| 39 | ||||
| 40 | 1 | 1µs | 1µs | *new_sequence = \&renew; |
| 41 | ||||
| 42 | sub needs_lines { 0 } | |||
| 43 | ||||
| 44 | sub perlio_ok { | |||
| 45 | eval { require PerlIO::encoding }; | |||
| 46 | return $@ ? 0 : 1; | |||
| 47 | } | |||
| 48 | ||||
| 49 | # (Temporary|legacy) methods | |||
| 50 | ||||
| 51 | sub toUnicode { shift->decode(@_) } | |||
| 52 | sub fromUnicode { shift->encode(@_) } | |||
| 53 | ||||
| 54 | # | |||
| 55 | # Needs to be overloaded or just croak | |||
| 56 | # | |||
| 57 | ||||
| 58 | sub encode { | |||
| 59 | require Carp; | |||
| 60 | my $obj = shift; | |||
| 61 | my $class = ref($obj) ? ref($obj) : $obj; | |||
| 62 | Carp::croak( $class . "->encode() not defined!" ); | |||
| 63 | } | |||
| 64 | ||||
| 65 | sub decode { | |||
| 66 | require Carp; | |||
| 67 | my $obj = shift; | |||
| 68 | my $class = ref($obj) ? ref($obj) : $obj; | |||
| 69 | Carp::croak( $class . "->encode() not defined!" ); | |||
| 70 | } | |||
| 71 | ||||
| 72 | sub DESTROY { } | |||
| 73 | ||||
| 74 | 1 | 7µs | 7µs | 1; |
| 75 | __END__ | |||
| 76 | ||||
| 77 | =head1 NAME | |||
| 78 | ||||
| 79 | Encode::Encoding - Encode Implementation Base Class | |||
| 80 | ||||
| 81 | =head1 SYNOPSIS | |||
| 82 | ||||
| 83 | package Encode::MyEncoding; | |||
| 84 | use base qw(Encode::Encoding); | |||
| 85 | ||||
| 86 | __PACKAGE__->Define(qw(myCanonical myAlias)); | |||
| 87 | ||||
| 88 | =head1 DESCRIPTION | |||
| 89 | ||||
| 90 | As mentioned in L<Encode>, encodings are (in the current | |||
| 91 | implementation at least) defined as objects. The mapping of encoding | |||
| 92 | name to object is via the C<%Encode::Encoding> hash. Though you can | |||
| 93 | directly manipulate this hash, it is strongly encouraged to use this | |||
| 94 | base class module and add encode() and decode() methods. | |||
| 95 | ||||
| 96 | =head2 Methods you should implement | |||
| 97 | ||||
| 98 | You are strongly encouraged to implement methods below, at least | |||
| 99 | either encode() or decode(). | |||
| 100 | ||||
| 101 | =over 4 | |||
| 102 | ||||
| 103 | =item -E<gt>encode($string [,$check]) | |||
| 104 | ||||
| 105 | MUST return the octet sequence representing I<$string>. | |||
| 106 | ||||
| 107 | =over 2 | |||
| 108 | ||||
| 109 | =item * | |||
| 110 | ||||
| 111 | If I<$check> is true, it SHOULD modify I<$string> in place to remove | |||
| 112 | the converted part (i.e. the whole string unless there is an error). | |||
| 113 | If perlio_ok() is true, SHOULD becomes MUST. | |||
| 114 | ||||
| 115 | =item * | |||
| 116 | ||||
| 117 | If an error occurs, it SHOULD return the octet sequence for the | |||
| 118 | fragment of string that has been converted and modify $string in-place | |||
| 119 | to remove the converted part leaving it starting with the problem | |||
| 120 | fragment. If perlio_ok() is true, SHOULD becomes MUST. | |||
| 121 | ||||
| 122 | =item * | |||
| 123 | ||||
| 124 | If I<$check> is is false then C<encode> MUST make a "best effort" to | |||
| 125 | convert the string - for example, by using a replacement character. | |||
| 126 | ||||
| 127 | =back | |||
| 128 | ||||
| 129 | =item -E<gt>decode($octets [,$check]) | |||
| 130 | ||||
| 131 | MUST return the string that I<$octets> represents. | |||
| 132 | ||||
| 133 | =over 2 | |||
| 134 | ||||
| 135 | =item * | |||
| 136 | ||||
| 137 | If I<$check> is true, it SHOULD modify I<$octets> in place to remove | |||
| 138 | the converted part (i.e. the whole sequence unless there is an | |||
| 139 | error). If perlio_ok() is true, SHOULD becomes MUST. | |||
| 140 | ||||
| 141 | =item * | |||
| 142 | ||||
| 143 | If an error occurs, it SHOULD return the fragment of string that has | |||
| 144 | been converted and modify $octets in-place to remove the converted | |||
| 145 | part leaving it starting with the problem fragment. If perlio_ok() is | |||
| 146 | true, SHOULD becomes MUST. | |||
| 147 | ||||
| 148 | =item * | |||
| 149 | ||||
| 150 | If I<$check> is false then C<decode> should make a "best effort" to | |||
| 151 | convert the string - for example by using Unicode's "\x{FFFD}" as a | |||
| 152 | replacement character. | |||
| 153 | ||||
| 154 | =back | |||
| 155 | ||||
| 156 | =back | |||
| 157 | ||||
| 158 | If you want your encoding to work with L<encoding> pragma, you should | |||
| 159 | also implement the method below. | |||
| 160 | ||||
| 161 | =over 4 | |||
| 162 | ||||
| 163 | =item -E<gt>cat_decode($destination, $octets, $offset, $terminator [,$check]) | |||
| 164 | ||||
| 165 | MUST decode I<$octets> with I<$offset> and concatenate it to I<$destination>. | |||
| 166 | Decoding will terminate when $terminator (a string) appears in output. | |||
| 167 | I<$offset> will be modified to the last $octets position at end of decode. | |||
| 168 | Returns true if $terminator appears output, else returns false. | |||
| 169 | ||||
| 170 | =back | |||
| 171 | ||||
| 172 | =head2 Other methods defined in Encode::Encodings | |||
| 173 | ||||
| 174 | You do not have to override methods shown below unless you have to. | |||
| 175 | ||||
| 176 | =over 4 | |||
| 177 | ||||
| 178 | =item -E<gt>name | |||
| 179 | ||||
| 180 | Predefined As: | |||
| 181 | ||||
| 182 | sub name { return shift->{'Name'} } | |||
| 183 | ||||
| 184 | MUST return the string representing the canonical name of the encoding. | |||
| 185 | ||||
| 186 | =item -E<gt>mime_name | |||
| 187 | ||||
| 188 | Predefined As: | |||
| 189 | ||||
| 190 | sub mime_name{ | |||
| 191 | require Encode::MIME::Name; | |||
| 192 | return Encode::MIME::Name::get_mime_name(shift->name); | |||
| 193 | } | |||
| 194 | ||||
| 195 | MUST return the string representing the IANA charset name of the encoding. | |||
| 196 | ||||
| 197 | =item -E<gt>renew | |||
| 198 | ||||
| 199 | Predefined As: | |||
| 200 | ||||
| 201 | sub renew { | |||
| 202 | my $self = shift; | |||
| 203 | my $clone = bless { %$self } => ref($self); | |||
| 204 | $clone->{renewed}++; | |||
| 205 | return $clone; | |||
| 206 | } | |||
| 207 | ||||
| 208 | This method reconstructs the encoding object if necessary. If you need | |||
| 209 | to store the state during encoding, this is where you clone your object. | |||
| 210 | ||||
| 211 | PerlIO ALWAYS calls this method to make sure it has its own private | |||
| 212 | encoding object. | |||
| 213 | ||||
| 214 | =item -E<gt>renewed | |||
| 215 | ||||
| 216 | Predefined As: | |||
| 217 | ||||
| 218 | sub renewed { $_[0]->{renewed} || 0 } | |||
| 219 | ||||
| 220 | Tells whether the object is renewed (and how many times). Some | |||
| 221 | modules emit C<Use of uninitialized value in null operation> warning | |||
| 222 | unless the value is numeric so return 0 for false. | |||
| 223 | ||||
| 224 | =item -E<gt>perlio_ok() | |||
| 225 | ||||
| 226 | Predefined As: | |||
| 227 | ||||
| 228 | sub perlio_ok { | |||
| 229 | eval{ require PerlIO::encoding }; | |||
| 230 | return $@ ? 0 : 1; | |||
| 231 | } | |||
| 232 | ||||
| 233 | If your encoding does not support PerlIO for some reasons, just; | |||
| 234 | ||||
| 235 | sub perlio_ok { 0 } | |||
| 236 | ||||
| 237 | =item -E<gt>needs_lines() | |||
| 238 | ||||
| 239 | Predefined As: | |||
| 240 | ||||
| 241 | sub needs_lines { 0 }; | |||
| 242 | ||||
| 243 | If your encoding can work with PerlIO but needs line buffering, you | |||
| 244 | MUST define this method so it returns true. 7bit ISO-2022 encodings | |||
| 245 | are one example that needs this. When this method is missing, false | |||
| 246 | is assumed. | |||
| 247 | ||||
| 248 | =back | |||
| 249 | ||||
| 250 | =head2 Example: Encode::ROT13 | |||
| 251 | ||||
| 252 | package Encode::ROT13; | |||
| 253 | use strict; | |||
| 254 | use base qw(Encode::Encoding); | |||
| 255 | ||||
| 256 | __PACKAGE__->Define('rot13'); | |||
| 257 | ||||
| 258 | sub encode($$;$){ | |||
| 259 | my ($obj, $str, $chk) = @_; | |||
| 260 | $str =~ tr/A-Za-z/N-ZA-Mn-za-m/; | |||
| 261 | $_[1] = '' if $chk; # this is what in-place edit means | |||
| 262 | return $str; | |||
| 263 | } | |||
| 264 | ||||
| 265 | # Jr pna or ynml yvxr guvf; | |||
| 266 | *decode = \&encode; | |||
| 267 | ||||
| 268 | 1; | |||
| 269 | ||||
| 270 | =head1 Why the heck Encode API is different? | |||
| 271 | ||||
| 272 | It should be noted that the I<$check> behaviour is different from the | |||
| 273 | outer public API. The logic is that the "unchecked" case is useful | |||
| 274 | when the encoding is part of a stream which may be reporting errors | |||
| 275 | (e.g. STDERR). In such cases, it is desirable to get everything | |||
| 276 | through somehow without causing additional errors which obscure the | |||
| 277 | original one. Also, the encoding is best placed to know what the | |||
| 278 | correct replacement character is, so if that is the desired behaviour | |||
| 279 | then letting low level code do it is the most efficient. | |||
| 280 | ||||
| 281 | By contrast, if I<$check> is true, the scheme above allows the | |||
| 282 | encoding to do as much as it can and tell the layer above how much | |||
| 283 | that was. What is lacking at present is a mechanism to report what | |||
| 284 | went wrong. The most likely interface will be an additional method | |||
| 285 | call to the object, or perhaps (to avoid forcing per-stream objects | |||
| 286 | on otherwise stateless encodings) an additional parameter. | |||
| 287 | ||||
| 288 | It is also highly desirable that encoding classes inherit from | |||
| 289 | C<Encode::Encoding> as a base class. This allows that class to define | |||
| 290 | additional behaviour for all encoding objects. | |||
| 291 | ||||
| 292 | package Encode::MyEncoding; | |||
| 293 | use base qw(Encode::Encoding); | |||
| 294 | ||||
| 295 | __PACKAGE__->Define(qw(myCanonical myAlias)); | |||
| 296 | ||||
| 297 | to create an object with C<< bless {Name => ...}, $class >>, and call | |||
| 298 | define_encoding. They inherit their C<name> method from | |||
| 299 | C<Encode::Encoding>. | |||
| 300 | ||||
| 301 | =head2 Compiled Encodings | |||
| 302 | ||||
| 303 | For the sake of speed and efficiency, most of the encodings are now | |||
| 304 | supported via a I<compiled form>: XS modules generated from UCM | |||
| 305 | files. Encode provides the enc2xs tool to achieve that. Please see | |||
| 306 | L<enc2xs> for more details. | |||
| 307 | ||||
| 308 | =head1 SEE ALSO | |||
| 309 | ||||
| 310 | L<perlmod>, L<enc2xs> | |||
| 311 | ||||
| 312 | =begin future | |||
| 313 | ||||
| 314 | =over 4 | |||
| 315 | ||||
| 316 | =item Scheme 1 | |||
| 317 | ||||
| 318 | The fixup routine gets passed the remaining fragment of string being | |||
| 319 | processed. It modifies it in place to remove bytes/characters it can | |||
| 320 | understand and returns a string used to represent them. For example: | |||
| 321 | ||||
| 322 | sub fixup { | |||
| 323 | my $ch = substr($_[0],0,1,''); | |||
| 324 | return sprintf("\x{%02X}",ord($ch); | |||
| 325 | } | |||
| 326 | ||||
| 327 | This scheme is close to how the underlying C code for Encode works, | |||
| 328 | but gives the fixup routine very little context. | |||
| 329 | ||||
| 330 | =item Scheme 2 | |||
| 331 | ||||
| 332 | The fixup routine gets passed the original string, an index into | |||
| 333 | it of the problem area, and the output string so far. It appends | |||
| 334 | what it wants to the output string and returns a new index into the | |||
| 335 | original string. For example: | |||
| 336 | ||||
| 337 | sub fixup { | |||
| 338 | # my ($s,$i,$d) = @_; | |||
| 339 | my $ch = substr($_[0],$_[1],1); | |||
| 340 | $_[2] .= sprintf("\x{%02X}",ord($ch); | |||
| 341 | return $_[1]+1; | |||
| 342 | } | |||
| 343 | ||||
| 344 | This scheme gives maximal control to the fixup routine but is more | |||
| 345 | complicated to code, and may require that the internals of Encode be tweaked to | |||
| 346 | keep the original string intact. | |||
| 347 | ||||
| 348 | =item Other Schemes | |||
| 349 | ||||
| 350 | Hybrids of the above. | |||
| 351 | ||||
| 352 | Multiple return values rather than in-place modifications. | |||
| 353 | ||||
| 354 | Index into the string could be C<pos($str)> allowing C<s/\G...//>. | |||
| 355 | ||||
| 356 | =back | |||
| 357 | ||||
| 358 | =end future | |||
| 359 | ||||
| 360 | =cut |