Net::SSH::Perl::BufferUser Contributed Perl DocumentaNet::SSH::Perl::Buffer(3)NAMENet::SSH::Perl::Buffer - Low-level read/write buffer class
SYNOPSIS
use Net::SSH::Perl::Buffer (@args);
my $buffer = Net::SSH::Perl::Buffer->new;
## Add a 32-bit integer.
$buffer->put_int32(10932930);
## Get it back.
my $int = $buffer->get_int32;
DESCRIPTIONNet::SSH::Perl::Buffer implements the low-level binary buffer needed by
the Net::SSH::Perl suite. Specifically, a Net::SSH::Perl::Buffer object
is what makes up the data segment of a packet transferred between
server and client (a Net::SSH::Perl::Packet object).
Buffers contain integers, strings, characters, etc. Because of the use
of GMP integers in SSH, buffers can also contain multiple-precision
integers (represented internally by Math::GMP objects).
Note: the method documentation here is in what some might call a
slightly backwards order. The reason for this is that the get and put
methods (listed first) are probably what most users/developers of
Net::SSH::Perl need to care about; they're high-level methods used to
get/put data from the buffer. The other methods (LOW-LEVEL METHODS) are
much more low-level, and typically you won't need to use them
explicitly.
GET AND PUT METHODS
All of the get_* and put_* methods respect the internal offset state in
the buffer object. This means that, for example, if you call get_int16
twice in a row, you can be ensured that you'll get the next two 16-bit
integers in the buffer. You don't need to worry about the number of
bytes a certain piece of data takes up, for example.
$buffer->get_int8
Returns the next 8-bit integer from the buffer (which is really just
the ASCII code for the next character/byte in the buffer).
$buffer->put_int8
Appends an 8-bit integer to the buffer (which is really just the
character corresponding to that integer, in ASCII).
$buffer->get_int16
Returns the next 16-bit integer from the buffer.
$buffer->put_int16($integer)
Appends a 16-bit integer to the buffer.
$buffer->get_int32
Returns the next 32-bit integer from the buffer.
$buffer->put_int32($integer)
Appends a 32-bit integer to the buffer.
$buffer->get_char
More appropriately called get_byte, perhaps, this returns the next byte
from the buffer.
$buffer->put_char($bytes)
Appends a byte (or a sequence of bytes) to the buffer. There is no
restriction on the length of the byte string $bytes; if it makes you
uncomfortable to call put_char to put multiple bytes, you can instead
call this method as put_chars. It's the same thing.
$buffer->get_str
Returns the next "string" from the buffer. A string here is represented
as the length of the string (a 32-bit integer) followed by the string
itself.
$buffer->put_str($string)
Appends a string (32-bit integer length and the string itself) to the
buffer.
$buffer->get_mp_int
Returns a bigint object representing a multiple precision integer read
from the buffer. Depending on the protocol, the object is either of
type Math::GMP (SSH1) or Math::Pari (SSH2).
You determine which protocol will be in use when you use the module:
specify SSH1 or SSH2 to load the proper get and put routines for
bigints:
use Net::SSH::Perl::Buffer qw( SSH1 );
$buffer->put_mp_int($mp_int)
Appends a multiple precision integer to the buffer. Depending on the
protocol in use, $mp_int should be either a Math::GMP object (SSH1) or
a Math::Pari object (SSH2). The format in which the integer is stored
in the buffer differs between the protocols, as well.
LOW-LEVEL METHODS
Net::SSH::Perl::Buffer->new
Creates a new buffer object and returns it. The buffer is empty.
This method takes no arguments.
$buffer->append($bytes)
Appends raw data $bytes to the end of the in-memory buffer. Generally
you don't need to use this method unless you're initializing an empty
buffer, because when you need to add data to a buffer you should
generally use one of the put_* methods.
$buffer->empty
Empties out the buffer object.
$buffer->bytes([ $offset [, $length [, $replacement ]]])
Behaves exactly like the substr built-in function, except on the buffer
$buffer. Given no arguments, bytes returns the entire buffer; given one
argument $offset, returns everything from that position to the end of
the string; given $offset and $length, returns the segment of the
buffer starting at $offset and consisting of $length bytes; and given
all three arguments, replaces that segment with $replacement.
This is a very low-level method, and you generally won't need to use
it.
Also be warned that you should not intermix use of this method with use
of the get_* and put_* methods; the latter classes of methods maintain
internal state of the buffer offset where arguments will be gotten from
and put, respectively. The bytes method gives no thought to this
internal offset state.
$buffer->length
Returns the length of the buffer object.
$buffer->offset
Returns the internal offset state.
If you insist on intermixing calls to bytes with calls to the get_* and
put_* methods, you'll probably want to use this method to get some
status on that internal offset.
$buffer->dump
Returns a hex dump of the buffer.
$buffer->insert_padding
A helper method: pads out the buffer so that the length of the
transferred packet will be evenly divisible by 8, which is a
requirement of the SSH protocol.
AUTHOR & COPYRIGHTS
Please see the Net::SSH::Perl manpage for author, copyright, and
license information.
perl v5.14.1 2008-10-02 Net::SSH::Perl::Buffer(3)
