Identify repeating patterns in .dat file

datpatterns.py

import struct
import re
from collections import Counter

class DatPatterns:
    def __init__(self, filepath):
        self.filepath = filepath
        self.content = None

    def read_file(self):
        with open(self.filepath, 'rb') as file:
            self.content = file.read()

    def find_repeating_patterns(self, pattern_size=4):
        pattern_counts = Counter()
        for i in range(len(self.content) - pattern_size):
            pattern = self.content[i:i + pattern_size]
            if re.match(b'\x00+', pattern):
                continue
            pattern_counts[pattern] += 1
        # Only consider patterns that repeat more than a threshold to indicate potential structure
        return {pattern: count for pattern, count in pattern_counts.items() if count > 3}

    def analyze_patterns(self, patterns):
        for pattern, count in patterns.items():
            print(f"\nAnalyzing Pattern {pattern.hex()} (occurrences: {count}):")
            pattern_pos = self.content.find(pattern)

            while pattern_pos != -1:
                # Example analysis: Print 10 bytes before and after the pattern
                context_before = self.content[max(0, pattern_pos-10):pattern_pos]
                context_after = self.content[pattern_pos+len(pattern):pattern_pos+len(pattern)+10]

                print(f"At offset {pattern_pos}: {context_before.hex()} [{pattern.hex()}] {context_after.hex()}")

                pattern_pos = self.content.find(pattern, pattern_pos + 1)

    def run(self):
        self.read_file()
        patterns = self.find_repeating_patterns()
        self.analyze_patterns(patterns)


if __name__ == "__main__":
    decoder = DatPatterns("/System/Library/PrivateFrameworks/CoreEmoji.framework/Versions/A/Resources/emoji.dat")
    decoder.run()