Pillow/PIL/_binary.py

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#
# 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.
#
if bytes is str:
def i8(c):
return ord(c)
def o8(i):
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return chr(i & 255)
else:
def i8(c):
return c if c.__class__ is int else c[0]
def o8(i):
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return bytes((i & 255,))
# Input, le = little endian, be = big endian
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# 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
"""
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return i8(c[o]) | (i8(c[o+1]) << 8)
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
"""
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return (i8(c[o]) | (i8(c[o+1]) << 8) | (i8(c[o+2]) << 16) |
(i8(c[o+3]) << 24))
def i16be(c, o=0):
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return (i8(c[o]) << 8) | i8(c[o+1])
def i32be(c, o=0):
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return ((i8(c[o]) << 24) | (i8(c[o+1]) << 16) |
(i8(c[o+2]) << 8) | i8(c[o+3]))
# Output, le = little endian, be = big endian
def o16le(i):
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return o8(i) + o8(i >> 8)
def o32le(i):
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return o8(i) + o8(i >> 8) + o8(i >> 16) + o8(i >> 24)
def o16be(i):
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return o8(i >> 8) + o8(i)
def o32be(i):
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return o8(i >> 24) + o8(i >> 16) + o8(i >> 8) + o8(i)
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# End of file