Nymiro
78 lines
2.3 KiB
Python
78 lines
2.3 KiB
Python
import struct
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class Box:
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"""
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Represents a generic ISOBMFF box.
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"""
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def __init__(self, size: int, box_type: str, offset: int, raw_data: bytes):
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self.size = size
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self.type = box_type
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self.offset = offset
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self.raw_data = raw_data
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self.children = [] # Will be populated for container boxes
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def __repr__(self) -> str:
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# e.g., <Box 'ftyp' size=36 offset=8>
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return f"<Box '{self.type}' size={self.size} offset={self.offset}>"
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# In parser.py
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from typing import List, BinaryIO
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def parse_boxes(stream: BinaryIO) -> List[Box]:
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"""
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Parses all top-level boxes from a file stream, handling special size cases.
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"""
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boxes = []
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stream.seek(0, 2)
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file_size = stream.tell()
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stream.seek(0)
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while stream.tell() < file_size:
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current_offset = stream.tell()
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# Read the standard 8-byte header
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header = stream.read(8)
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if len(header) < 8:
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break
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size = struct.unpack('>I', header[:4])[0]
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box_type = header[4:].decode('ascii')
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header_size = 8
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content_size = 0
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# --- NEW: Handle special size cases ---
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if size == 1:
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# The actual size is a 64-bit integer following the type
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largesize_header = stream.read(8)
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if len(largesize_header) < 8:
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break
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size = struct.unpack('>Q', largesize_header)[0]
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header_size = 16
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content_size = size - header_size
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elif size == 0:
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# The box extends to the end of the file
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content_size = file_size - current_offset - header_size
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size = content_size + header_size
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else:
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# Standard size
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content_size = size - header_size
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# --- End of new code ---
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# Read the box's content (raw_data)
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# We need to rewind a bit if we read largesize header to get all content
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stream.seek(current_offset + header_size)
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raw_data = stream.read(content_size)
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if len(raw_data) < content_size:
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# Avoids errors on truncated files
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break
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box = Box(size, box_type, current_offset, raw_data)
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boxes.append(box)
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# Seek to the beginning of the next box
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stream.seek(current_offset + size)
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return boxes |