metasploit-framework/lib/postgres/buffer.rb

106 lines
1.8 KiB
Ruby

require 'postgres_msf'
require 'postgres/binary_writer'
require 'postgres/binary_reader'
# Namespace for Metasploit branch.
module Msf
module Db
# Fixed size buffer.
class Buffer
class Error < RuntimeError; end
class EOF < Error; end
def self.from_string(str)
new(str)
end
def self.of_size(size)
raise ArgumentError if size < 0
new('#' * size)
end
def initialize(content)
@size = content.size
@content = content
@position = 0
end
def size
@size
end
def position
@position
end
def position=(new_pos)
raise ArgumentError if new_pos < 0 or new_pos > @size
@position = new_pos
end
def at_end?
@position == @size
end
def content
@content
end
def read(n)
raise EOF, 'cannot read beyond the end of buffer' if @position + n > @size
str = @content[@position, n]
@position += n
str
end
def write(str)
sz = str.size
raise EOF, 'cannot write beyond the end of buffer' if @position + sz > @size
@content[@position, sz] = str
@position += sz
self
end
def copy_from_stream(stream, n)
raise ArgumentError if n < 0
while n > 0
str = stream.read(n)
write(str)
n -= str.size
end
raise if n < 0
end
NUL = "\000"
def write_cstring(cstr)
raise ArgumentError, "Invalid Ruby/cstring" if cstr.include?(NUL)
write(cstr)
write(NUL)
end
# returns a Ruby string without the trailing NUL character
def read_cstring
nul_pos = @content.index(NUL, @position)
raise Error, "no cstring found!" unless nul_pos
sz = nul_pos - @position
str = @content[@position, sz]
@position += sz + 1
return str
end
# read till the end of the buffer
def read_rest
read(self.size-@position)
end
include BinaryWriterMixin
include BinaryReaderMixin
end
end
end