58 lines
1.5 KiB
Python
58 lines
1.5 KiB
Python
import struct
|
|
|
|
|
|
def _make_packer(format_string):
|
|
try:
|
|
packer = struct.Struct(format_string) # new in Python 2.5
|
|
except AttributeError:
|
|
pack = lambda x: struct.pack(format_string, x)
|
|
unpack = lambda s: struct.unpack(format_string, s)
|
|
else:
|
|
pack = packer.pack
|
|
unpack = lambda s: packer.unpack(s)[0]
|
|
return pack, unpack
|
|
|
|
int64_pack, int64_unpack = _make_packer('>q')
|
|
int32_pack, int32_unpack = _make_packer('>i')
|
|
int16_pack, int16_unpack = _make_packer('>h')
|
|
int8_pack, int8_unpack = _make_packer('>b')
|
|
uint64_pack, uint64_unpack = _make_packer('>Q')
|
|
uint32_pack, uint32_unpack = _make_packer('>I')
|
|
uint16_pack, uint16_unpack = _make_packer('>H')
|
|
uint8_pack, uint8_unpack = _make_packer('>B')
|
|
float_pack, float_unpack = _make_packer('>f')
|
|
double_pack, double_unpack = _make_packer('>d')
|
|
|
|
|
|
def varint_unpack(term):
|
|
val = int(term.encode('hex'), 16)
|
|
if (ord(term[0]) & 128) != 0:
|
|
val = val - (1 << (len(term) * 8))
|
|
return val
|
|
|
|
|
|
def bitlength(n):
|
|
bitlen = 0
|
|
while n > 0:
|
|
n >>= 1
|
|
bitlen += 1
|
|
return bitlen
|
|
|
|
|
|
def varint_pack(big):
|
|
pos = True
|
|
if big == 0:
|
|
return '\x00'
|
|
if big < 0:
|
|
bytelength = bitlength(abs(big) - 1) / 8 + 1
|
|
big = (1 << bytelength * 8) + big
|
|
pos = False
|
|
revbytes = []
|
|
while big > 0:
|
|
revbytes.append(chr(big & 0xff))
|
|
big >>= 8
|
|
if pos and ord(revbytes[-1]) & 0x80:
|
|
revbytes.append('\x00')
|
|
revbytes.reverse()
|
|
return ''.join(revbytes)
|