SickGear/lib/hachoir/subfile/search.py

251 lines
8.9 KiB
Python

from hachoir.stream import InputSubStream
from hachoir.core.tools import humanFilesize, humanDuration
from hachoir.core.memory import limitedMemory
from hachoir.subfile.data_rate import DataRate
from hachoir.subfile.output import Output
from hachoir.subfile.pattern import HachoirPatternMatching as PatternMatching
from sys import stderr
from time import time
def skipSubfile(parser):
subfile = parser.getParserTags().get("subfile", "")
return (subfile == "skip")
FILE_MAX_SIZE = 100 * 1024 * 1024 # Max. file size in bytes (100 MB)
SLICE_SIZE = 64 * 1024 # Slice size in bytes (64 KB)
MEMORY_LIMIT = 50 * 1024 * 1024
PROGRESS_UPDATE = 1.5 # Minimum number of second between two progress messages
class SearchSubfile:
"""
Tool to find file start and file size in any binary stream.
To use it:
- instanciate the class: subfile = SearchSubfile()
- (optional) choose magics with: subfile.loadMagics(categories, parser_ids)
- run the search: subfile.main()
"""
def __init__(self, stream, offset=0, size=None):
"""
Setup search tool, parameter:
- filename: Input filename in locale charset
- directory: Directory filename in locale charset where
output files will be written
- offset: Offset (in bytes) of the beginning of the search
- size: Limit size (in bytes) of input file (None: no limit)
- debug: Debug mode flag (display debug information)
"""
# Size
self.stream = stream
if size is not None:
self.size = min(self.stream.size, (offset + size) * 8)
else:
self.size = self.stream.size
# Offset
self.start_offset = offset * 8
self.current_offset = self.start_offset
self.slice_size = SLICE_SIZE * 8 # 64 KB (in bits)
# Statistics
self.datarate = DataRate(self.start_offset)
self.main_start = time()
# Other flags and attributes
self.patterns = None
self.verbose = True
self.debug = False
self.output = None
self.filter = None
def setOutput(self, directory):
self.output = Output(directory)
def loadParsers(self, categories=None, parser_ids=None):
before = time()
self.patterns = PatternMatching(categories, parser_ids)
if self.debug:
print("Regex compilation: %.1f ms" % ((time() - before) * 1000))
print("Use regex: %s" % self.patterns)
def main(self):
"""
Run the search.
Return True if ok, False otherwise.
"""
# Initialize
self.mainHeader()
# Prepare search
main_error = False
try:
# Run search
limitedMemory(MEMORY_LIMIT, self.searchSubfiles)
except KeyboardInterrupt:
print("[!] Program interrupted (CTRL+C)", file=stderr)
main_error = True
except MemoryError:
main_error = True
print("[!] Memory error!", file=stderr)
self.mainFooter()
self.stream.close()
return (not main_error)
def mainHeader(self):
# Fix slice size if needed
self.slice_size = max(self.slice_size, self.patterns.max_length * 8)
# Load parsers if none has been choosen
if not self.patterns:
self.loadParsers()
bytes = (self.size - self.start_offset) // 8
print("[+] Start search on %s bytes (%s)" % (
bytes, humanFilesize(bytes)), file=stderr)
print(file=stderr)
self.stats = {}
self.current_offset = self.start_offset
self.main_start = time()
def mainFooter(self):
print(file=stderr)
print("[+] End of search -- offset=%s (%s)" % (
self.current_offset // 8, humanFilesize(self.current_offset // 8)), file=stderr)
size = (self.current_offset - self.start_offset) // 8
duration = time() - self.main_start
if 0.1 <= duration:
print("Total time: %s -- global rate: %s/sec" % (
humanDuration(duration * 1000), humanFilesize(size // duration)), file=stderr)
def searchSubfiles(self):
"""
Search all subfiles in the stream, call processParser() for each parser.
"""
self.next_offset = None
self.next_progress = time() + PROGRESS_UPDATE
while self.current_offset < self.size:
self.datarate.update(self.current_offset)
if self.verbose and self.next_progress <= time():
self.displayProgress()
for offset, parser in self.findMagic(self.current_offset):
self.processParser(offset, parser)
self.current_offset += self.slice_size
if self.next_offset:
self.current_offset = max(
self.current_offset, self.next_offset)
self.current_offset = min(self.current_offset, self.size)
def processParser(self, offset, parser):
"""
Process a valid parser.
"""
text = "[+] File at %s" % (offset // 8)
if parser.content_size is not None:
text += " size=%s (%s)" % (parser.content_size //
8, humanFilesize(parser.content_size // 8))
if not parser.content_size or parser.content_size // 8 < FILE_MAX_SIZE:
text += ": " + parser.description
else:
text += ": " + parser.__class__.__name__
if self.output and parser.content_size:
if (offset == 0 and parser.content_size == self.size):
text += " (don't copy whole file)"
elif parser.content_size // 8 >= FILE_MAX_SIZE:
text += " (don't copy file, too big)"
elif not self.filter or self.filter(parser):
filename = self.output.createFilename(parser.filename_suffix)
filename = self.output.writeFile(
filename, self.stream, offset, parser.content_size)
text += " => %s" % filename
print(text)
self.next_progress = time() + PROGRESS_UPDATE
def findMagic(self, offset):
"""
Find all 'magic_str' strings in stream in offset interval:
offset..(offset+self.slice_size).
The function returns a generator with values (offset, parser) where
offset is beginning of a file (relative to stream begin), and not the
position of the magic.
"""
start = offset
end = start + self.slice_size
end = min(end, self.size)
data = self.stream.readBytes(start, (end - start) // 8)
for parser_cls, offset in self.patterns.search(data):
offset += start
# Skip invalid offset
if offset < 0:
continue
if self.next_offset and offset < self.next_offset:
continue
# Create parser at found offset
parser = self.guess(offset, parser_cls)
# Update statistics
if parser_cls not in self.stats:
self.stats[parser_cls] = [0, 0]
self.stats[parser_cls][0] += 1
if not parser:
continue
# Parser is valid, yield it with the offset
self.stats[parser_cls][1] += 1
if self.debug:
print("Found %s at offset %s" % (
parser.__class__.__name__, offset // 8), file=stderr)
yield (offset, parser)
# Set next offset
if parser.content_size is not None\
and skipSubfile(parser):
self.next_offset = offset + parser.content_size
if end <= self.next_offset:
break
def guess(self, offset, parser_cls):
"""
Try the specified parser at stream offset 'offset'.
Return the parser object, or None on failure.
"""
substream = InputSubStream(self.stream, offset)
try:
return parser_cls(substream, validate=True)
except Exception:
return None
def displayProgress(self):
"""
Display progress (to stdout) of the whole process.
Compute data rate (in byte per sec) and time estimation.
"""
# Program next update
self.next_progress = time() + PROGRESS_UPDATE
# Progress offset
percent = float(self.current_offset - self.start_offset) * \
100 / (self.size - self.start_offset)
offset = self.current_offset // 8
message = "Search: %.2f%% -- offset=%u (%s)" % (
percent, offset, humanFilesize(offset))
# Compute data rate (byte/sec)
average = self.datarate.average
if average:
message += " -- %s/sec " % humanFilesize(average // 8)
eta = float(self.size - self.current_offset) / average
message += " -- ETA: %s" % humanDuration(eta * 1000)
# Display message
print(message, file=stderr)