37 lines
866 B
GDScript
37 lines
866 B
GDScript
extends Node
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func ByteArray(size: int) -> PoolByteArray:
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var arr := PoolByteArray()
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arr.resize(size)
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return arr
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func LZ77_decompress(rom: File, address: int) -> PoolByteArray:
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rom.seek(address)
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var header := rom.get_32()
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assert (header & 0x10 == 0x10)
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var length := header >> 8
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var output := ByteArray(length)
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var ptr := 0
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while ptr < length:
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var bitmap := rom.get_8()
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for i in range(8):
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if (bitmap >> (7-i)) & 1:
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# Buffer substitution
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var h1 := rom.get_8()
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var h2 := rom.get_8()
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var copy_len := 3 + (h1 >> 4)
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var copy_ptr := ptr - 1 - (((h1 & 0x0F)<<8) + h2)
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for j in range(copy_len):
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output[ptr] = output[copy_ptr]
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copy_ptr += 1
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ptr += 1
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if ptr >= length:
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return output
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else:
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# Literal byte
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output[ptr] = rom.get_8()
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ptr += 1
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if ptr >= length:
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return output
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return output
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