77 lines
1.5 KiB
Python
77 lines
1.5 KiB
Python
#
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# The Python Imaging Library.
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# $Id$
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#
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# Binary input/output support routines.
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#
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# Copyright (c) 1997-2003 by Secret Labs AB
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# Copyright (c) 1995-2003 by Fredrik Lundh
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# Copyright (c) 2012 by Brian Crowell
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#
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# See the README file for information on usage and redistribution.
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#
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if bytes is str:
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def i8(c):
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return ord(c)
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def o8(i):
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return chr(i & 255)
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else:
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def i8(c):
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return c if c.__class__ is int else c[0]
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def o8(i):
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return bytes((i & 255,))
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# Input, le = little endian, be = big endian
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# TODO: replace with more readable struct.unpack equivalent
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def i16le(c, o=0):
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"""
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Converts a 2-bytes (16 bits) string to an integer.
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c: string containing bytes to convert
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o: offset of bytes to convert in string
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"""
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return i8(c[o]) | (i8(c[o+1]) << 8)
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def i32le(c, o=0):
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"""
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Converts a 4-bytes (32 bits) string to an integer.
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c: string containing bytes to convert
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o: offset of bytes to convert in string
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"""
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return (i8(c[o]) | (i8(c[o+1]) << 8) | (i8(c[o+2]) << 16) |
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(i8(c[o+3]) << 24))
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def i16be(c, o=0):
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return (i8(c[o]) << 8) | i8(c[o+1])
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def i32be(c, o=0):
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return ((i8(c[o]) << 24) | (i8(c[o+1]) << 16) |
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(i8(c[o+2]) << 8) | i8(c[o+3]))
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# Output, le = little endian, be = big endian
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def o16le(i):
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return o8(i) + o8(i >> 8)
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def o32le(i):
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return o8(i) + o8(i >> 8) + o8(i >> 16) + o8(i >> 24)
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def o16be(i):
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return o8(i >> 8) + o8(i)
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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
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