实现 AppleHandler 和 SamsungHandler 类，处理特定于供应商的 HEIC 特性，添加查找嵌入视频的逻辑

heic_file.py

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+import os
+from base import Box
+from parser import parse_boxes
+from heic_types import ItemLocationBox
+
+# Import handlers
+from handlers.base_handler import VendorHandler
+from handlers.apple_handler import AppleHandler
+from handlers.samsung_handler import SamsungHandler
+
+class HEICFile:
+    def __init__(self, filepath: str):
+        self.filepath = filepath
+        self._iloc_box: ItemLocationBox = None
+        self._ftyp_box: Box = None
+        self.handler: VendorHandler = None # Will hold our strategy object
+
+        with open(self.filepath, 'rb') as f:
+            file_size = os.fstat(f.fileno()).st_size
+            self.boxes = parse_boxes(f, file_size)
+            
+            self._find_essential_boxes(self.boxes)
+            self._detect_vendor()
+
+    def _find_essential_boxes(self, boxes: list[Box]):
+        """Recursively search for essential boxes."""
+        for box in boxes:
+            if box.type == 'iloc': self._iloc_box = box
+            if box.type == 'ftyp': self._ftyp_box = box
+            if box.children: self._find_essential_boxes(box.children)
+
+    def _detect_vendor(self):
+        """
+        Inspects the 'ftyp' box to determine the vendor and assign the correct handler.
+        """
+        if self._ftyp_box:
+            compatible_brands = self._ftyp_box.raw_data[4:].decode('ascii', errors='ignore')
+            if 'samsung' in compatible_brands.lower() or 'mpvd' in [b.type for b in self.boxes]:
+                 self.handler = SamsungHandler()
+                 return
+            if 'apple' in compatible_brands.lower() or 'MiHB' in compatible_brands:
+                 self.handler = AppleHandler()
+                 return
+        
+        # If no specific handler is found, use the base one.
+        print("Could not detect a specific vendor. Using default handler.")
+        self.handler = VendorHandler()
+
+
+    def get_item_data(self, item_id: int) -> bytes | None:
+        # ... (this method remains unchanged) ...
+        if not self._iloc_box:
+            print("Error: 'iloc' box not found.")
+            return None
+        location = next((loc for loc in self._iloc_box.locations if loc.item_id == item_id), None)
+        if not location:
+            print(f"Error: Item with ID {item_id} not found in 'iloc' box.")
+            return None
+        with open(self.filepath, 'rb') as f:
+            # IMPORTANT: iloc offsets are absolute from the start of the file.
+            # The mdat box's offset is not needed for this calculation.
+            f.seek(location.offset)
+            data = f.read(location.length)
+            return data
+
+    def get_motion_photo_data(self) -> bytes | None:
+        """
+        Delegates the search for motion photo data to the assigned vendor handler.
+        """
+        offset = self.handler.find_motion_photo_offset(self)
+        if offset is not None:
+            with open(self.filepath, 'rb') as f:
+                # We assume the video data goes to the end of the file from its offset
+                f.seek(offset)
+                return f.read()
+        return None