| File | /usr/local/lib/perl5/5.8.8/bytes.pm |
| Statements Executed | 16 |
| Statement Execution Time | 361µs |
| Calls | P | F | Exclusive Time |
Inclusive Time |
Subroutine |
|---|---|---|---|---|---|
| 13 | 13 | 13 | 189µs | 189µs | bytes::import |
| 0 | 0 | 0 | 0s | 0s | bytes::AUTOLOAD |
| 0 | 0 | 0 | 0s | 0s | bytes::unimport |
| Line | State ments |
Time on line |
Calls | Time in subs |
Code |
|---|---|---|---|---|---|
| 1 | package bytes; | ||||
| 2 | |||||
| 3 | 1 | 6µs | our $VERSION = '1.02'; | ||
| 4 | |||||
| 5 | 1 | 5µs | $bytes::hint_bits = 0x00000008; | ||
| 6 | |||||
| 7 | # spent 189µs within bytes::import which was called 13 times, avg 15µs/call:
# once (17µs+0s) by Net::HTTP::Methods::zlib_ok at line 18 of IO/Compress/Base.pm
# once (16µs+0s) by Net::HTTP::Methods::zlib_ok at line 5 of IO/Compress/Base/Common.pm
# once (15µs+0s) by Net::HTTP::Methods::zlib_ok at line 5 of IO/Compress/Adapter/Deflate.pm
# once (15µs+0s) by Net::HTTP::Methods::zlib_ok at line 5 of IO/Uncompress/Adapter/Inflate.pm
# once (15µs+0s) by Net::HTTP::Methods::zlib_ok at line 5 of IO/Compress/Gzip/Constants.pm
# once (14µs+0s) by Net::HTTP::Methods::zlib_ok at line 13 of Compress/Raw/Zlib.pm
# once (14µs+0s) by Net::HTTP::Methods::zlib_ok at line 6 of IO/Uncompress/RawInflate.pm
# once (14µs+0s) by Net::HTTP::Methods::zlib_ok at line 8 of IO/Compress/Gzip.pm
# once (14µs+0s) by Net::HTTP::Methods::zlib_ok at line 6 of IO/Uncompress/Base.pm
# once (14µs+0s) by Net::HTTP::Methods::zlib_ok at line 7 of IO/Compress/RawDeflate.pm
# once (14µs+0s) by Net::HTTP::Methods::zlib_ok at line 10 of IO/Uncompress/Gunzip.pm
# once (14µs+0s) by Net::HTTP::Methods::zlib_ok at line 18 of Compress/Zlib.pm
# once (13µs+0s) by Net::HTTP::Methods::zlib_ok at line 7 of IO/Compress/Zlib/Extra.pm | ||||
| 8 | 13 | 338µs | $^H |= $bytes::hint_bits; | ||
| 9 | } | ||||
| 10 | |||||
| 11 | sub unimport { | ||||
| 12 | $^H &= ~$bytes::hint_bits; | ||||
| 13 | } | ||||
| 14 | |||||
| 15 | sub AUTOLOAD { | ||||
| 16 | require "bytes_heavy.pl"; | ||||
| 17 | goto &$AUTOLOAD if defined &$AUTOLOAD; | ||||
| 18 | require Carp; | ||||
| 19 | Carp::croak("Undefined subroutine $AUTOLOAD called"); | ||||
| 20 | } | ||||
| 21 | |||||
| 22 | sub length ($); | ||||
| 23 | sub chr ($); | ||||
| 24 | sub ord ($); | ||||
| 25 | sub substr ($$;$$); | ||||
| 26 | sub index ($$;$); | ||||
| 27 | sub rindex ($$;$); | ||||
| 28 | |||||
| 29 | 1 | 12µs | 1; | ||
| 30 | __END__ | ||||
| 31 | |||||
| 32 | =head1 NAME | ||||
| 33 | |||||
| 34 | bytes - Perl pragma to force byte semantics rather than character semantics | ||||
| 35 | |||||
| 36 | =head1 SYNOPSIS | ||||
| 37 | |||||
| 38 | use bytes; | ||||
| 39 | ... chr(...); # or bytes::chr | ||||
| 40 | ... index(...); # or bytes::index | ||||
| 41 | ... length(...); # or bytes::length | ||||
| 42 | ... ord(...); # or bytes::ord | ||||
| 43 | ... rindex(...); # or bytes::rindex | ||||
| 44 | ... substr(...); # or bytes::substr | ||||
| 45 | no bytes; | ||||
| 46 | |||||
| 47 | |||||
| 48 | =head1 DESCRIPTION | ||||
| 49 | |||||
| 50 | The C<use bytes> pragma disables character semantics for the rest of the | ||||
| 51 | lexical scope in which it appears. C<no bytes> can be used to reverse | ||||
| 52 | the effect of C<use bytes> within the current lexical scope. | ||||
| 53 | |||||
| 54 | Perl normally assumes character semantics in the presence of character | ||||
| 55 | data (i.e. data that has come from a source that has been marked as | ||||
| 56 | being of a particular character encoding). When C<use bytes> is in | ||||
| 57 | effect, the encoding is temporarily ignored, and each string is treated | ||||
| 58 | as a series of bytes. | ||||
| 59 | |||||
| 60 | As an example, when Perl sees C<$x = chr(400)>, it encodes the character | ||||
| 61 | in UTF-8 and stores it in $x. Then it is marked as character data, so, | ||||
| 62 | for instance, C<length $x> returns C<1>. However, in the scope of the | ||||
| 63 | C<bytes> pragma, $x is treated as a series of bytes - the bytes that make | ||||
| 64 | up the UTF8 encoding - and C<length $x> returns C<2>: | ||||
| 65 | |||||
| 66 | $x = chr(400); | ||||
| 67 | print "Length is ", length $x, "\n"; # "Length is 1" | ||||
| 68 | printf "Contents are %vd\n", $x; # "Contents are 400" | ||||
| 69 | { | ||||
| 70 | use bytes; # or "require bytes; bytes::length()" | ||||
| 71 | print "Length is ", length $x, "\n"; # "Length is 2" | ||||
| 72 | printf "Contents are %vd\n", $x; # "Contents are 198.144" | ||||
| 73 | } | ||||
| 74 | |||||
| 75 | chr(), ord(), substr(), index() and rindex() behave similarly. | ||||
| 76 | |||||
| 77 | For more on the implications and differences between character | ||||
| 78 | semantics and byte semantics, see L<perluniintro> and L<perlunicode>. | ||||
| 79 | |||||
| 80 | =head1 LIMITATIONS | ||||
| 81 | |||||
| 82 | bytes::substr() does not work as an lvalue(). | ||||
| 83 | |||||
| 84 | =head1 SEE ALSO | ||||
| 85 | |||||
| 86 | L<perluniintro>, L<perlunicode>, L<utf8> | ||||
| 87 | |||||
| 88 | =cut |