# Copyright 2010-2012 RethinkDB, all rights reserved.

from collections import namedtuple

import struct

def parse_prim(format):

def parse(block, offset = 0):

value, = struct.unpack_from(format, block, offset)

return (value, offset + struct.calcsize(format))

return parse

parse_int = parse_prim('i')

parse_uint8_t = parse_prim('B')

parse_uint16_t = parse_prim('H')

parse_uint32_t = parse_prim('I')

parse_uint64_t = parse_prim('Q')

parse_off64_t = parse_prim('q')

def make_struct(name, names_and_parsers):

ty = namedtuple(name, [x[0] for x in names_and_parsers if x[0] is not None])

def parse(block, offset = 0):

assert isinstance(block, str)

assert isinstance(offset, (int, long))

values = []

for name, parser in names_and_parsers:

value, offset = parser(block, offset)

if name is not None: values.append(value)

return ty(*values), offset

return ty, parse

def parse_padding(size):

def parse(block, offset = 0):

return None, offset + size

return parse

def parse_constant(string):

def parse(block, offset = 0):

val = block[offset : offset + len(string)]

if val != string:

raise ValueError("Expected %r, got %r." % (string, val))

return None, offset + struct.calcsize("%ds" % len(string))

return parse

def parse_array(parser, count):

def parse(block, offset = 0):

values = []

for i in range(count):

value, offset = parser(block, offset)

values.append(value)

return values, offset

return parse