Pillow/PIL/_binary.py

75 lines
1.4 KiB
Python

#
# The Python Imaging Library.
# $Id$
#
# Binary input/output support routines.
#
# Copyright (c) 1997-2003 by Secret Labs AB
# Copyright (c) 1995-2003 by Fredrik Lundh
# Copyright (c) 2012 by Brian Crowell
#
# See the README file for information on usage and redistribution.
#
from struct import unpack, pack
if bytes is str:
def i8(c):
return ord(c)
def o8(i):
return chr(i & 255)
else:
def i8(c):
return c if c.__class__ is int else c[0]
def o8(i):
return bytes((i & 255,))
# Input, le = little endian, be = big endian
# TODO: replace with more readable struct.unpack equivalent
def i16le(c, o=0):
"""
Converts a 2-bytes (16 bits) string to an integer.
c: string containing bytes to convert
o: offset of bytes to convert in string
"""
return unpack("<H", c[o:o+2])[0]
def i32le(c, o=0):
"""
Converts a 4-bytes (32 bits) string to an integer.
c: string containing bytes to convert
o: offset of bytes to convert in string
"""
return unpack("<I", c[o:o+4])[0]
def i16be(c, o=0):
return unpack(">H", c[o:o+2])[0]
def i32be(c, o=0):
return unpack(">I", c[o:o+4])[0]
# Output, le = little endian, be = big endian
def o16le(i):
return pack("<H", i)
def o32le(i):
return pack("<I", i)
def o16be(i):
return pack(">H", i)
def o32be(i):
return pack(">I", i)