diff options
author | Norbert Preining <norbert@preining.info> | 2019-09-02 13:46:59 +0900 |
---|---|---|
committer | Norbert Preining <norbert@preining.info> | 2019-09-02 13:46:59 +0900 |
commit | e0c6872cf40896c7be36b11dcc744620f10adf1d (patch) | |
tree | 60335e10d2f4354b0674ec22d7b53f0f8abee672 /systems/texlive/tlnet/tlpkg/tlperl/lib/IO/Seekable.pm |
Initial commit
Diffstat (limited to 'systems/texlive/tlnet/tlpkg/tlperl/lib/IO/Seekable.pm')
-rw-r--r-- | systems/texlive/tlnet/tlpkg/tlperl/lib/IO/Seekable.pm | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/systems/texlive/tlnet/tlpkg/tlperl/lib/IO/Seekable.pm b/systems/texlive/tlnet/tlpkg/tlperl/lib/IO/Seekable.pm new file mode 100644 index 0000000000..27ed663445 --- /dev/null +++ b/systems/texlive/tlnet/tlpkg/tlperl/lib/IO/Seekable.pm @@ -0,0 +1,126 @@ +# + +package IO::Seekable; + +=head1 NAME + +IO::Seekable - supply seek based methods for I/O objects + +=head1 SYNOPSIS + + use IO::Seekable; + package IO::Something; + @ISA = qw(IO::Seekable); + +=head1 DESCRIPTION + +C<IO::Seekable> does not have a constructor of its own as it is intended to +be inherited by other C<IO::Handle> based objects. It provides methods +which allow seeking of the file descriptors. + +=over 4 + +=item $io->getpos + +Returns an opaque value that represents the current position of the +IO::File, or C<undef> if this is not possible (eg an unseekable stream such +as a terminal, pipe or socket). If the fgetpos() function is available in +your C library it is used to implements getpos, else perl emulates getpos +using C's ftell() function. + +=item $io->setpos + +Uses the value of a previous getpos call to return to a previously visited +position. Returns "0 but true" on success, C<undef> on failure. + +=back + +See L<perlfunc> for complete descriptions of each of the following +supported C<IO::Seekable> methods, which are just front ends for the +corresponding built-in functions: + +=over 4 + +=item $io->seek ( POS, WHENCE ) + +Seek the IO::File to position POS, relative to WHENCE: + +=over 8 + +=item WHENCE=0 (SEEK_SET) + +POS is absolute position. (Seek relative to the start of the file) + +=item WHENCE=1 (SEEK_CUR) + +POS is an offset from the current position. (Seek relative to current) + +=item WHENCE=2 (SEEK_END) + +POS is an offset from the end of the file. (Seek relative to end) + +=back + +The SEEK_* constants can be imported from the C<Fcntl> module if you +don't wish to use the numbers C<0> C<1> or C<2> in your code. + +Returns C<1> upon success, C<0> otherwise. + +=item $io->sysseek( POS, WHENCE ) + +Similar to $io->seek, but sets the IO::File's position using the system +call lseek(2) directly, so will confuse most perl IO operators except +sysread and syswrite (see L<perlfunc> for full details) + +Returns the new position, or C<undef> on failure. A position +of zero is returned as the string C<"0 but true"> + +=item $io->tell + +Returns the IO::File's current position, or -1 on error. + +=back + +=head1 SEE ALSO + +L<perlfunc>, +L<perlop/"I/O Operators">, +L<IO::Handle> +L<IO::File> + +=head1 HISTORY + +Derived from FileHandle.pm by Graham Barr E<lt>gbarr@pobox.comE<gt> + +=cut + +use 5.008_001; +use Carp; +use strict; +use IO::Handle (); +# XXX we can't get these from IO::Handle or we'll get prototype +# mismatch warnings on C<use POSIX; use IO::File;> :-( +use Fcntl qw(SEEK_SET SEEK_CUR SEEK_END); +require Exporter; + +our @EXPORT = qw(SEEK_SET SEEK_CUR SEEK_END); +our @ISA = qw(Exporter); + +our $VERSION = "1.39"; + +sub seek { + @_ == 3 or croak 'usage: $io->seek(POS, WHENCE)'; + seek($_[0], $_[1], $_[2]); +} + +sub sysseek { + @_ == 3 or croak 'usage: $io->sysseek(POS, WHENCE)'; + sysseek($_[0], $_[1], $_[2]); +} + +sub tell { + @_ == 1 or croak 'usage: $io->tell()'; + tell($_[0]); +} + +1; |