SickGear/lib/hachoir_parser/archive/gzip_parser.py
2015-08-20 16:48:28 +01:00

129 lines
4.6 KiB
Python

"""
GZIP archive parser.
Author: Victor Stinner
"""
from hachoir_parser import Parser
from hachoir_core.field import (
UInt8, UInt16, UInt32, Enum, TimestampUnix32,
Bit, CString, SubFile,
NullBits, Bytes, RawBytes)
from hachoir_core.text_handler import textHandler, hexadecimal, filesizeHandler
from hachoir_core.endian import LITTLE_ENDIAN
from hachoir_parser.common.deflate import Deflate
class GzipParser(Parser):
endian = LITTLE_ENDIAN
PARSER_TAGS = {
"id": "gzip",
"category": "archive",
"file_ext": ("gz",),
"mime": (u"application/x-gzip",),
"min_size": 18*8,
#"magic": (('\x1F\x8B\x08', 0),),
"magic_regex": (
# (magic, compression=deflate, <flags>, <mtime>, )
('\x1F\x8B\x08.{5}[\0\2\4\6][\x00-\x0D]', 0),
),
"description": u"gzip archive",
}
os_name = {
0: u"FAT filesystem",
1: u"Amiga",
2: u"VMS (or OpenVMS)",
3: u"Unix",
4: u"VM/CMS",
5: u"Atari TOS",
6: u"HPFS filesystem (OS/2, NT)",
7: u"Macintosh",
8: u"Z-System",
9: u"CP/M",
10: u"TOPS-20",
11: u"NTFS filesystem (NT)",
12: u"QDOS",
13: u"Acorn RISCOS",
}
COMPRESSION_NAME = {
8: u"deflate",
}
def validate(self):
if self["signature"].value != '\x1F\x8B':
return "Invalid signature"
if self["compression"].value not in self.COMPRESSION_NAME:
return "Unknown compression method (%u)" % self["compression"].value
if self["reserved[0]"].value != 0:
return "Invalid reserved[0] value"
if self["reserved[1]"].value != 0:
return "Invalid reserved[1] value"
if self["reserved[2]"].value != 0:
return "Invalid reserved[2] value"
return True
def createFields(self):
# Gzip header
yield Bytes(self, "signature", 2, r"GZip file signature (\x1F\x8B)")
yield Enum(UInt8(self, "compression", "Compression method"), self.COMPRESSION_NAME)
# Flags
yield Bit(self, "is_text", "File content is probably ASCII text")
yield Bit(self, "has_crc16", "Header CRC16")
yield Bit(self, "has_extra", "Extra informations (variable size)")
yield Bit(self, "has_filename", "Contains filename?")
yield Bit(self, "has_comment", "Contains comment?")
yield NullBits(self, "reserved[]", 3)
yield TimestampUnix32(self, "mtime", "Modification time")
# Extra flags
yield NullBits(self, "reserved[]", 1)
yield Bit(self, "slowest", "Compressor used maximum compression (slowest)")
yield Bit(self, "fastest", "Compressor used the fastest compression")
yield NullBits(self, "reserved[]", 5)
yield Enum(UInt8(self, "os", "Operating system"), self.os_name)
# Optional fields
if self["has_extra"].value:
yield UInt16(self, "extra_length", "Extra length")
yield RawBytes(self, "extra", self["extra_length"].value, "Extra")
if self["has_filename"].value:
yield CString(self, "filename", "Filename", charset="ISO-8859-1")
if self["has_comment"].value:
yield CString(self, "comment", "Comment")
if self["has_crc16"].value:
yield textHandler(UInt16(self, "hdr_crc16", "CRC16 of the header"),
hexadecimal)
if self._size is None: # TODO: is it possible to handle piped input?
raise NotImplementedError()
# Read file
size = (self._size - self.current_size) // 8 - 8 # -8: crc32+size
if 0 < size:
if self["has_filename"].value:
filename = self["filename"].value
else:
for tag, filename in self.stream.tags:
if tag == "filename" and filename.endswith(".gz"):
filename = filename[:-3]
break
else:
filename = None
yield Deflate(SubFile(self, "file", size, filename=filename))
# Footer
yield textHandler(UInt32(self, "crc32",
"Uncompressed data content CRC32"), hexadecimal)
yield filesizeHandler(UInt32(self, "size", "Uncompressed size"))
def createDescription(self):
desc = u"gzip archive"
info = []
if "filename" in self:
info.append('filename "%s"' % self["filename"].value)
if "size" in self:
info.append("was %s" % self["size"].display)
if self["mtime"].value:
info.append(self["mtime"].display)
return "%s: %s" % (desc, ", ".join(info))