[project @ Arch-1:robey@lag.net--2003-public%secsh--dev--1.0--patch-24]

document more of Message; add get_int64
all of the get_* methods are now documented, but there's a bit more to do.
get_int64 added for eventual sftp support.
This commit is contained in:
Robey Pointer 2004-01-27 01:45:44 +00:00
parent 35ed103572
commit ea8c1378e8
1 changed files with 106 additions and 8 deletions

View File

@ -26,29 +26,71 @@ import string, types, struct
from util import inflate_long, deflate_long
class Message(object):
"represents the encoding of an SSH2 message"
class Message (object):
"""
An SSH2 I{Message} is a stream of bytes that encodes some combination of
strings, integers, bools, and infinite-precision integers (known in python
as I{long}s). This class builds or breaks down such a byte stream.
"""
def __init__(self, content=''):
"""
Create a new SSH2 Message.
@param content: the byte stream to use as the Message content (usually
passed in only when decomposing a Message).
@type content: string
"""
self.packet = content
self.idx = 0
self.seqno = -1
def __str__(self):
"""
Return the byte stream content of this Message, as a string.
@return: the contents of this Message.
@rtype: string
"""
return self.packet
def __repr__(self):
"""
Returns a string representation of this object, for debugging.
@rtype: string
"""
return 'Message(' + repr(self.packet) + ')'
def get_remainder(self):
"remaining bytes still unparsed"
"""
Return the bytes of this Message that haven't already been parsed and
returned.
@return: a string of the bytes not parsed yet.
@rtype: string
"""
return self.packet[self.idx:]
def get_so_far(self):
"bytes that have been parsed"
"""
Returns the bytes of this Message that have been parsed and returned.
The string passed into a Message's constructor can be regenerated by
concatenating C{get_so_far} and L{get_remainder}.
@return: a string of the bytes parsed so far.
@rtype: string
"""
return self.packet[:self.idx]
def get_bytes(self, n):
"""
Return the next C{n} bytes of the Message, without decomposing into
an int, string, etc. Just the raw bytes are returned.
@return: a string of the next C{n} bytes of the Message, or a string
of C{n} zero bytes, if there aren't C{n} bytes remaining.
@rtype: string
"""
if self.idx + n > len(self.packet):
return '\x00'*n
b = self.packet[self.idx:self.idx+n]
@ -56,16 +98,36 @@ class Message(object):
return b
def get_byte(self):
"""
Return the next byte of the Message, without decomposing it. This
is equivalent to L{get_bytes(1)<get_bytes>}.
@return: the next byte of the Message, or C{'\000'} if there aren't
any bytes remaining.
@rtype: string
"""
return self.get_bytes(1)
def get_boolean(self):
"""
Fetch a boolean from the stream.
@return: C{True} or C{False} (from the Message).
@rtype: bool
"""
b = self.get_bytes(1)
if b == '\x00':
return 0
return False
else:
return 1
return True
def get_int(self):
"""
Fetch an int from the stream.
@return: a 32-bit unsigned integer.
@rtype: int
"""
x = self.packet
i = self.idx
if i + 4 > len(x):
@ -74,10 +136,39 @@ class Message(object):
self.idx = i+4
return n
def get_int64(self):
"""
Fetch a 64-bit int from the stream.
@return: a 64-bit unsigned integer.
@rtype: long
"""
x = self.packet
i = self.idx
if i + 8 > len(x):
return 0L
n = struct.unpack('>Q', x[i:i+8])[0]
self.idx += 8
return n
def get_mpint(self):
"""
Fetch a long int (mpint) from the stream.
@return: an arbitrary-length integer.
@rtype: long
"""
return inflate_long(self.get_string())
def get_string(self):
"""
Fetch a string from the stream. This could be a byte string and may
contain unprintable characters. (It's not unheard of for a string to
contain another byte-stream Message.)
@return: a string.
@rtype: string
"""
l = self.get_int()
if self.idx + l > len(self.packet):
return ''
@ -86,6 +177,13 @@ class Message(object):
return str
def get_list(self):
"""
Fetch a list of strings from the stream. These are trivially encoded
as comma-separated values in a string.
@return: a list of strings.
@type: list of strings
"""
str = self.get_string()
l = string.split(str, ',')
return l