NAME Data::TxnBuffer - binary read/write buffer supporting transaction read SYNOPSIS use Data::TxnBuffer; # create buffer my $buf = Data::TxnBuffer->new; # or create buffer from some data my $buf = Data::TxnBuffer->new($data); # read some data use Try::Tiny; try { my $u32 = $buf->read_u32; # read unsigned int my $bytes = $buf->read(10); # read 10 bytes $buf->spin; # all data received. clear these data from buffer. } catch { $buf->reset; # reset read cursor. try again later }; # or more easy way. this way automatically call spin or reset method like above. try { $buf->txn_read(sub { my $u32 = $buf->read_u32; # read unsigned int my $bytes = $buf->read(10); # read 10 bytes }); } catch { # try again later }; # write some data to filehandle or buffer $buf->write_u32(100); $buf->write("Hello World"); # got written data my $data = $buf->data; # clear all data from buffer $buf->clear; DESCRIPTION Data::TxnBuffer provides some binary buffering functions, such as basic read/write function for buffer, more convenience r/w methods (read_u32/write_u32, etc), and transaction read method. XS implementation This module use XS implementation by default, but fallback to ::PP implementation in pure perl environment or "PERL_ONLY" environment variable is set. XS implementation is several times faster than PP implementation. CLASS METHOD my $buf = Data::TxnBuffer->new($data); Create a Data::TxnBuffer object. If you passed some $data, create buffer from the data. ACCESSORS $buf->cursor Return buffer read cursor point. This value increase by "read" methods automatically and reset to 0 by "reset" method. $buf->data Return buffer's whole data. BASIC METHODS $buf->read($bytes) Read $bytes data from buffer and return the data. If there's not enough data in buffer, throw exception. $buf->write($data) Write $data into buffer. $buf->spin $buf->write('foo'); $buf->write('bar'); my $foo = $buf->read(3); # foo $buf->spin; # clear only foo $buf->data; # == 'bar' Clear *only* read data from buffer. When read cursor == 0, this method does nothing. And also, this method returns cleared data. For example "$buf->spin" in above example returns 'foo'; $buf->reset Reset read cursor to 0. $buf->clear Clear all data from buffer. TRANSACTION READ By combination of "read", "spin", and "reset" methods, you can read some data like transaction: use Try::Tiny; try { my $foo = $buf->read(3); my $bar = $buf->read(3); $buf->spin; # clear read data 'foobar' } catch { $buf->reset; }; "read" method throw exception if there's not enough data in buffer, catch this exception and reset read cursor, then you can read first data again after some seconds. $buf->txn_read($code) Shortcut method for above transaction read example. use Try::Tiny; try { $buf->txn_read(sub { my $foo = $buf->read(3); my $bar = $buf->read(3); }); # spin automatically called } catch { # reset automatically called # try later }; This method automatically call "spin" method and returns "spin"'ed data if all data successfully read, or throw exception not enough data in buffer and call "reset" method automatically. This method is very useful for typical transaction read functions. READ/WRITE HELPER METHODS This module provides not only basic "read($bytes)" method but also useful methods to read integer values easily. $buf->read_u32 $buf->read_u24 $buf->read_u16 $buf->read_u8 Read unsigned integers. "uXX" is bit length. (ex: u32 is 32bit unsigned int) $buf->read_i32 $buf->read_i24 $buf->read_i16 $buf->read_i8 Read singed integers. $buf->write_u32 $buf->write_u24 $buf->write_u16 $buf->write_u8 Write unsigned integers $buf->write_i32 $buf->write_i24 $buf->write_i16 $buf->write_i8 Write signed integers (In XS implementation, this is just an alias to write_uXX) $buf->read_n32 $buf->read_n24 $buf->read_n16 $buf->write_n32 $buf->write_n24 $buf->write_n16 Read/Write unsigned integers in network byte order. $buf->read_float $buf->read_double $buf->write_float $buf->write_double Read/Write floating points (float = 32bit single precision float, double = 64bit double precision float) AUTHOR Daisuke Murase COPYRIGHT AND LICENSE Copyright (c) 2011 by KAYAC Inc. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of the license can be found in the LICENSE file included with this module.