更新 HEICFile 和相关类以支持 'iref' 功能，添加获取网格布局的方法，增强文件分析功能
This commit is contained in:
Nymiro
+82
-47
@@ -30,8 +30,8 @@ class ItemLocationBox(Box):
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for _ in range(item_count):
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item_id = struct.unpack('>H', stream[current_pos : current_pos+2])[0]
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current_pos += 2
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current_pos += 2
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current_pos += base_offset_size
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current_pos += 2 # Skip 2 bytes of construction_method
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current_pos += base_offset_size # Skip base_offset
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extent_count = struct.unpack('>H', stream[current_pos : current_pos+2])[0]
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current_pos += 2
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if extent_count > 0:
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@@ -61,9 +61,13 @@ class ItemInfoBox(Box):
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self.entries: list[ItemInfoEntry] = []
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self._parse_entries()
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def _parse_entries(self):
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# Assumes version 0 of 'iinf' box
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if len(self.raw_data) < 6: return
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item_count = struct.unpack('>H', self.raw_data[4:6])[0]
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for infe_box in self.children:
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if infe_box.type == 'infe':
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# Assumes version 2 of 'infe' box
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if len(infe_box.raw_data) < 12: continue
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item_id = struct.unpack('>H', infe_box.raw_data[4:6])[0]
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item_type = infe_box.raw_data[8:12].decode('ascii').strip('\x00')
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item_name_bytes = infe_box.raw_data[12:]
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@@ -76,15 +80,14 @@ class PrimaryItemBox(Box):
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self.item_id: int = 0
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self._parse_item_id()
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def _parse_item_id(self):
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# Assumes version 0 of 'pitm' box
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if len(self.raw_data) < 6: return
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self.item_id = struct.unpack('>H', self.raw_data[4:6])[0]
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# --- NEW classes for Task 3.1 & 3.2 ---
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class ImageSpatialExtentsBox(Box):
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"""'ispe' box, contains image dimensions."""
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def __init__(self, size: int, box_type: str, offset: int, raw_data: bytes):
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super().__init__(size, box_type, offset, raw_data)
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# 'ispe' is a FullBox
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self.image_width = struct.unpack('>I', self.raw_data[4:8])[0]
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self.image_height = struct.unpack('>I', self.raw_data[8:12])[0]
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def __repr__(self):
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@@ -95,7 +98,7 @@ class ItemPropertyAssociationEntry:
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def __init__(self, item_id, association_count):
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self.item_id = item_id
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self.association_count = association_count
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self.associations = [] # List of property indices
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self.associations = []
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def __repr__(self):
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return f"<ItemPropertyAssociationEntry item_id={self.item_id} associations={self.associations}>"
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@@ -108,60 +111,30 @@ class ItemPropertyAssociationBox(Box):
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def _parse_associations(self):
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stream = self.raw_data
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# A FullBox has a 4-byte header (version + flags)
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version_flags = struct.unpack('>I', stream[:4])[0]
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version = version_flags >> 24
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flags = version_flags & 0xFFFFFF
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entry_count = struct.unpack('>I', stream[4:8])[0]
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pos = 8
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# Determine field sizes based on the box version and flags
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item_id_size = 4 if version >= 1 else 2
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is_large_property_index = (flags & 1) == 1
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for _ in range(entry_count):
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# Boundary check for the item ID
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if pos + item_id_size > len(stream):
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break
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if item_id_size == 4:
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item_id = struct.unpack('>I', stream[pos:pos+4])[0]
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pos += 4
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else: # item_id_size == 2
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item_id = struct.unpack('>H', stream[pos:pos+2])[0]
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pos += 2
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# Boundary check for association_count
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if pos + 1 > len(stream):
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break
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if pos + item_id_size > len(stream): break
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item_id = struct.unpack('>I' if item_id_size == 4 else '>H', stream[pos:pos+item_id_size])[0]
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pos += item_id_size
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if pos + 1 > len(stream): break
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association_count = stream[pos]
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pos += 1
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entry = ItemPropertyAssociationEntry(item_id, association_count)
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for __ in range(association_count):
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if is_large_property_index:
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# 2-byte association entry
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if pos + 2 > len(stream):
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break # Not enough data
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assoc_value = struct.unpack('>H', stream[pos:pos+2])[0]
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property_index = assoc_value & 0x7FFF # Lower 15 bits
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pos += 2
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else:
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# 1-byte association entry
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if pos + 1 > len(stream):
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break # Not enough data
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assoc_value = stream[pos]
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property_index = assoc_value & 0x7F # Lower 7 bits
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pos += 1
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# A property_index of 0 is not a valid index.
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prop_size = 2 if is_large_property_index else 1
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if pos + prop_size > len(stream): break
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assoc_value = struct.unpack('>H' if prop_size == 2 else '>B', stream[pos:pos+prop_size])[0]
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property_index = assoc_value & (0x7FFF if prop_size == 2 else 0x7F)
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pos += prop_size
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if property_index > 0:
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entry.associations.append(property_index)
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self.entries[item_id] = entry
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class ItemPropertyContainerBox(Box):
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@@ -170,7 +143,6 @@ class ItemPropertyContainerBox(Box):
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class ItemPropertiesBox(Box):
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"""'iprp' box. Container for 'ipco' and 'ipma'."""
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@property
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def ipco(self) -> ItemPropertyContainerBox | None:
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"""Finds and returns the 'ipco' child box if it exists."""
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@@ -185,4 +157,67 @@ class ItemPropertiesBox(Box):
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for child in self.children:
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if isinstance(child, ItemPropertyAssociationBox):
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return child
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return None
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return None
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# --- NEW classes for Task 3.1 ('iref') ---
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class ItemReferenceEntry:
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"""Helper class for a single reference in the 'iref' box."""
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def __init__(self, from_id, to_ids):
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self.from_item_id = from_id
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self.to_item_ids = to_ids
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def __repr__(self):
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return f"<ItemReferenceEntry from={self.from_item_id} to={self.to_item_ids}>"
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class ItemReferenceBox(Box):
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"""'iref' box, describes relationships between items."""
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def __init__(self, size: int, box_type: str, offset: int, raw_data: bytes):
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super().__init__(size, box_type, offset, raw_data)
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self.references: dict[int, list[int]] = {}
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self._parse_references()
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def _parse_references(self):
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stream = self.raw_data
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version_flags = struct.unpack('>I', stream[:4])[0]
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version = version_flags >> 24
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pos = 4
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item_id_size = 4 if version == 1 else 2
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# The 'iref' box contains one or more SingleItemTypeReferenceBox(es)
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# We parse them in a loop until we run out of data.
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while pos < len(stream):
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# Each sub-box has its own size and type
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if pos + 8 > len(stream): break
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ref_box_size = struct.unpack('>I', stream[pos:pos+4])[0]
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ref_box_type = stream[pos+4:pos+8].decode('ascii')
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if pos + ref_box_size > len(stream): break
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# We are interested in 'grid', but could parse others like 'thmb'
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# The structure is the same for SingleItemTypeReferenceBox
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if item_id_size == 4:
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from_item_id = struct.unpack('>I', stream[pos+8:pos+12])[0]
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ref_count_pos = pos + 12
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else: # item_id_size == 2
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from_item_id = struct.unpack('>H', stream[pos+8:pos+10])[0]
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ref_count_pos = pos + 10
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reference_count = struct.unpack('>H', stream[ref_count_pos:ref_count_pos+2])[0]
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to_ids_pos = ref_count_pos + 2
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to_item_ids = []
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for _ in range(reference_count):
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if to_ids_pos + item_id_size > len(stream): break
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if item_id_size == 4:
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to_id = struct.unpack('>I', stream[to_ids_pos:to_ids_pos+4])[0]
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else: # item_id_size == 2
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to_id = struct.unpack('>H', stream[to_ids_pos:to_ids_pos+2])[0]
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to_item_ids.append(to_id)
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to_ids_pos += item_id_size
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self.references[from_item_id] = to_item_ids
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# Move to the next reference box within 'iref'
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pos += ref_box_size
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