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https://github.com/SickGear/SickGear.git
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336 lines
14 KiB
Python
336 lines
14 KiB
Python
"""Detailed ZLIB parser
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Author: Robert Xiao
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Creation date: July 9 2007
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"""
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from hachoir.parser import Parser
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from hachoir.field import (Bit, Bits, Field, Int16, UInt32,
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Enum, FieldSet, GenericFieldSet,
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PaddingBits, ParserError, RawBytes)
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from hachoir.core.endian import LITTLE_ENDIAN
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from hachoir.core.text_handler import textHandler, hexadecimal
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from hachoir.core.tools import paddingSize, alignValue
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def extend_data(data, length, offset):
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"""Extend data using a length and an offset."""
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if length >= offset:
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new_data = data[-offset:] * (alignValue(length, offset) // offset)
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return data + new_data[:length]
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else:
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return data + data[-offset:-offset + length]
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def build_tree(lengths):
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"""Build a Huffman tree from a list of lengths.
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The ith entry of the input list is the length of the Huffman code corresponding to
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integer i, or 0 if the integer i is unused."""
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max_length = max(lengths) + 1
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bit_counts = [0] * max_length
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next_code = [0] * max_length
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tree = {}
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for i in lengths:
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if i:
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bit_counts[i] += 1
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code = 0
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for i in range(1, len(bit_counts)):
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next_code[i] = code = (code + bit_counts[i - 1]) << 1
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for i, ln in enumerate(lengths):
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if ln:
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tree[(ln, next_code[ln])] = i
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next_code[ln] += 1
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return tree
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class HuffmanCode(Field):
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"""Huffman code. Uses tree parameter as the Huffman tree."""
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def __init__(self, parent, name, tree, description=None):
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Field.__init__(self, parent, name, 0, description)
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endian = self.parent.endian
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stream = self.parent.stream
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addr = self.absolute_address
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value = 0
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while (self.size, value) not in tree:
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if self.size > 256:
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raise ParserError("Huffman code too long!")
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bit = stream.readBits(addr, 1, endian)
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value <<= 1
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value += bit
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self._size += 1
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addr += 1
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self.huffvalue = value
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self.realvalue = tree[(self.size, value)]
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def createValue(self):
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return self.huffvalue
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class DeflateBlock(FieldSet):
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# code: (min, max, extrabits)
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LENGTH_SYMBOLS = {257: (3, 3, 0),
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258: (4, 4, 0),
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259: (5, 5, 0),
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260: (6, 6, 0),
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261: (7, 7, 0),
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262: (8, 8, 0),
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263: (9, 9, 0),
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264: (10, 10, 0),
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265: (11, 12, 1),
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266: (13, 14, 1),
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267: (15, 16, 1),
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268: (17, 18, 1),
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269: (19, 22, 2),
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270: (23, 26, 2),
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271: (27, 30, 2),
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272: (31, 34, 2),
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273: (35, 42, 3),
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274: (43, 50, 3),
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275: (51, 58, 3),
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276: (59, 66, 3),
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277: (67, 82, 4),
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278: (83, 98, 4),
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279: (99, 114, 4),
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280: (115, 130, 4),
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281: (131, 162, 5),
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282: (163, 194, 5),
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283: (195, 226, 5),
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284: (227, 257, 5),
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285: (258, 258, 0)
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}
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DISTANCE_SYMBOLS = {0: (1, 1, 0),
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1: (2, 2, 0),
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2: (3, 3, 0),
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3: (4, 4, 0),
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4: (5, 6, 1),
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5: (7, 8, 1),
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6: (9, 12, 2),
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7: (13, 16, 2),
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8: (17, 24, 3),
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9: (25, 32, 3),
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10: (33, 48, 4),
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11: (49, 64, 4),
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12: (65, 96, 5),
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13: (97, 128, 5),
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14: (129, 192, 6),
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15: (193, 256, 6),
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16: (257, 384, 7),
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17: (385, 512, 7),
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18: (513, 768, 8),
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19: (769, 1024, 8),
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20: (1025, 1536, 9),
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21: (1537, 2048, 9),
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22: (2049, 3072, 10),
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23: (3073, 4096, 10),
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24: (4097, 6144, 11),
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25: (6145, 8192, 11),
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26: (8193, 12288, 12),
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27: (12289, 16384, 12),
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28: (16385, 24576, 13),
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29: (24577, 32768, 13),
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}
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CODE_LENGTH_ORDER = [16, 17, 18, 0, 8, 7, 9,
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6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15]
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def __init__(self, parent, name, uncomp_data="", *args, **kwargs):
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FieldSet.__init__(self, parent, name, *args, **kwargs)
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self.uncomp_data = uncomp_data
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def createFields(self):
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yield Bit(self, "final", "Is this the final block?") # BFINAL
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yield Enum(Bits(self, "compression_type", 2), # BTYPE
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{0: "None", 1: "Fixed Huffman", 2: "Dynamic Huffman", 3: "Reserved"})
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if self["compression_type"].value == 0: # no compression
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# align on byte boundary
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padding = paddingSize(self.current_size + self.absolute_address, 8)
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if padding:
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yield PaddingBits(self, "padding[]", padding)
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yield Int16(self, "len")
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yield Int16(self, "nlen", "One's complement of len")
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if self["len"].value != ~self["nlen"].value:
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raise ParserError(
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"len must be equal to the one's complement of nlen!")
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# null stored blocks produced by some encoders (e.g. PIL)
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if self["len"].value:
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yield RawBytes(self, "data", self["len"].value, "Uncompressed data")
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return
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elif self["compression_type"].value == 1: # Fixed Huffman
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length_tree = {} # (size, huffman code): value
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distance_tree = {}
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for i in range(144):
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length_tree[(8, i + 48)] = i
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for i in range(144, 256):
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length_tree[(9, i + 256)] = i
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for i in range(256, 280):
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length_tree[(7, i - 256)] = i
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for i in range(280, 288):
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length_tree[(8, i - 88)] = i
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for i in range(32):
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distance_tree[(5, i)] = i
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elif self["compression_type"].value == 2: # Dynamic Huffman
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yield Bits(self, "huff_num_length_codes", 5, "Number of Literal/Length Codes, minus 257")
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yield Bits(self, "huff_num_distance_codes", 5, "Number of Distance Codes, minus 1")
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yield Bits(self, "huff_num_code_length_codes", 4, "Number of Code Length Codes, minus 4")
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code_length_code_lengths = [0] * 19 # confusing variable name...
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for i in self.CODE_LENGTH_ORDER[:self["huff_num_code_length_codes"].value + 4]:
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field = Bits(
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self, "huff_code_length_code[%i]" % i, 3, "Code lengths for the code length alphabet")
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yield field
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code_length_code_lengths[i] = field.value
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code_length_tree = build_tree(code_length_code_lengths)
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length_code_lengths = []
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distance_code_lengths = []
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for numcodes, name, lengths in (
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(self["huff_num_length_codes"].value +
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257, "length", length_code_lengths),
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(self["huff_num_distance_codes"].value + 1, "distance", distance_code_lengths)):
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while len(lengths) < numcodes:
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field = HuffmanCode(self, "huff_%s_code[]" %
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name, code_length_tree)
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value = field.realvalue
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if value < 16:
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prev_value = value
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field._description = "Literal Code Length %i (Huffman Code %i)" % (
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value, field.value)
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yield field
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lengths.append(value)
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else:
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info = {16: (3, 6, 2),
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17: (3, 10, 3),
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18: (11, 138, 7)}[value]
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if value == 16:
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repvalue = prev_value
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else:
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repvalue = 0
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field._description = "Repeat Code %i, Repeating value (%i) %i to %i times (Huffman Code %i)" % (
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value, repvalue, info[0], info[1], field.value)
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yield field
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extrafield = Bits(self, "huff_%s_code_extra[%s" % (
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name, field.name.split('[')[1]), info[2])
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num_repeats = extrafield.value + info[0]
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extrafield._description = "Repeat Extra Bits (%i), total repeats %i" % (
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extrafield.value, num_repeats)
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yield extrafield
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lengths += [repvalue] * num_repeats
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length_tree = build_tree(length_code_lengths)
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distance_tree = build_tree(distance_code_lengths)
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else:
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raise ParserError("Unsupported compression type 3!")
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while True:
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field = HuffmanCode(self, "length_code[]", length_tree)
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value = field.realvalue
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if value < 256:
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field._description = "Literal Code %r (Huffman Code %i)" % (
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chr(value), field.value)
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yield field
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self.uncomp_data += chr(value)
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if value == 256:
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field._description = "Block Terminator Code (256) (Huffman Code %i)" % field.value
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yield field
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break
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elif value > 256:
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info = self.LENGTH_SYMBOLS[value]
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if info[2] == 0:
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field._description = "Length Code %i, Value %i (Huffman Code %i)" % (
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value, info[0], field.value)
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length = info[0]
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yield field
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else:
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field._description = "Length Code %i, Values %i to %i (Huffman Code %i)" % (
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value, info[0], info[1], field.value)
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yield field
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extrafield = Bits(
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self, "length_extra[%s" % field.name.split('[')[1], info[2])
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length = extrafield.value + info[0]
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extrafield._description = "Length Extra Bits (%i), total length %i" % (
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extrafield.value, length)
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yield extrafield
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field = HuffmanCode(self, "distance_code[]", distance_tree)
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value = field.realvalue
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info = self.DISTANCE_SYMBOLS[value]
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if info[2] == 0:
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field._description = "Distance Code %i, Value %i (Huffman Code %i)" % (
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value, info[0], field.value)
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distance = info[0]
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yield field
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else:
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field._description = "Distance Code %i, Values %i to %i (Huffman Code %i)" % (
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value, info[0], info[1], field.value)
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yield field
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extrafield = Bits(
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self, "distance_extra[%s" % field.name.split('[')[1], info[2])
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distance = extrafield.value + info[0]
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extrafield._description = "Distance Extra Bits (%i), total length %i" % (
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extrafield.value, distance)
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yield extrafield
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self.uncomp_data = extend_data(
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self.uncomp_data, length, distance)
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class DeflateData(GenericFieldSet):
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endian = LITTLE_ENDIAN
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def createFields(self):
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uncomp_data = ""
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blk = DeflateBlock(self, "compressed_block[]", uncomp_data)
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yield blk
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uncomp_data = blk.uncomp_data
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while not blk["final"].value:
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blk = DeflateBlock(self, "compressed_block[]", uncomp_data)
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yield blk
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uncomp_data = blk.uncomp_data
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# align on byte boundary
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padding = paddingSize(self.current_size + self.absolute_address, 8)
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if padding:
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yield PaddingBits(self, "padding[]", padding)
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self.uncompressed_data = uncomp_data
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class ZlibData(Parser):
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PARSER_TAGS = {
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"id": "zlib",
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"category": "archive",
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"file_ext": ("zlib",),
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"min_size": 8 * 8,
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"description": "ZLIB Data",
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}
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endian = LITTLE_ENDIAN
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def validate(self):
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if self["compression_method"].value != 8:
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return "Incorrect compression method"
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if ((self["compression_info"].value << 12) +
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(self["compression_method"].value << 8) +
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(self["flag_compression_level"].value << 6) +
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(self["flag_dictionary_present"].value << 5) +
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(self["flag_check_bits"].value)) % 31 != 0:
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return "Invalid flag check value"
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return True
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def createFields(self):
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# CM
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yield Enum(Bits(self, "compression_method", 4), {8: "deflate", 15: "reserved"})
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# CINFO
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yield Bits(self, "compression_info", 4, "base-2 log of the window size")
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yield Bits(self, "flag_check_bits", 5) # FCHECK
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yield Bit(self, "flag_dictionary_present") # FDICT
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yield Enum(Bits(self, "flag_compression_level", 2), # FLEVEL
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{0: "Fastest", 1: "Fast", 2: "Default", 3: "Maximum, Slowest"})
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if self["flag_dictionary_present"].value:
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yield textHandler(UInt32(self, "dict_checksum", "ADLER32 checksum of dictionary information"), hexadecimal)
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yield DeflateData(self, "data", self.stream, description="Compressed Data")
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yield textHandler(UInt32(self, "data_checksum", "ADLER32 checksum of compressed data"), hexadecimal)
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def zlib_inflate(stream, wbits=None, prevdata=""):
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if wbits is None or wbits >= 0:
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return ZlibData(stream)["data"].uncompressed_data
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else:
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data = DeflateData(None, "root", stream, "", stream.askSize(None))
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for unused in data:
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pass
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return data.uncompressed_data
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