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https://github.com/notwa/mm
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60 lines
1.3 KiB
Cython
60 lines
1.3 KiB
Cython
# decoder ripped from: http://www.amnoid.de/gc/yaz0.txt
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from libc.stdint cimport uint32_t, uint8_t
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ctypedef uint32_t ulong
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ctypedef uint8_t uchar
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cdef ulong get_size(uchar *comp):
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return comp[4]*0x1000000 + comp[5]*0x10000 + comp[6]*0x100 + comp[7]
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cdef void _decode(uchar *comp, uchar *uncomp):
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cdef:
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ulong src = 16 # skip header
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ulong dst = 0
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uchar valid = 0 # bit count
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uchar curr = 0 # code byte
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ulong size = get_size(comp)
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uchar byte1, byte2
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ulong dist, copy, i, n
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while dst < size:
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if not valid:
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curr = comp[src]
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src += 1
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valid = 8
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if curr & 0x80:
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uncomp[dst] = comp[src]
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dst += 1
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src += 1
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else:
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byte1 = comp[src]
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byte2 = comp[src + 1]
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src += 2
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dist = ((byte1 & 0xF) << 8) | byte2
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copy = dst - (dist + 1)
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n = byte1 >> 4
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if n:
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n += 2
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else:
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n = comp[src] + 0x12
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src += 1
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for i in range(n):
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uncomp[dst] = uncomp[copy]
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copy += 1
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dst += 1
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curr <<= 1
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valid -= 1
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def decode(comp):
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size = get_size(comp)
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uncomp = bytearray(size)
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_decode(comp, uncomp)
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return uncomp
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