更新 HEICFile 类以支持新特性，添加图像尺寸获取功能，重构解析逻辑，增强代码可读性和健壮性
This commit is contained in:
Nymiro
+117
-26
@@ -1,8 +1,11 @@
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# pyheic_struct/heic_types.py
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import struct
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from base import Box # <-- THIS IS THE KEY CHANGE
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from base import Box
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# --- Existing classes (unchanged) ---
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class ItemLocation:
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# ... (rest of this class is unchanged)
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def __init__(self, item_id, offset, length):
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self.item_id = item_id
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self.offset = offset
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@@ -11,13 +14,11 @@ class ItemLocation:
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return f"<ItemLocation ID={self.item_id} offset={self.offset} length={self.length}>"
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class ItemLocationBox(Box):
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# ... (rest of this class is unchanged)
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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.locations = []
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self._parse_locations()
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def _parse_locations(self):
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# ... (all the parsing logic here is unchanged)
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stream = self.raw_data
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version_flags = struct.unpack('>I', stream[:4])[0]
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sizes = struct.unpack('>H', stream[4:6])[0]
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@@ -28,8 +29,8 @@ class ItemLocationBox(Box):
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current_pos = 8
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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 # Skip construction_method
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current_pos += 2 # Skip data_reference_index
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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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extent_count = struct.unpack('>H', stream[current_pos : current_pos+2])[0]
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current_pos += 2
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@@ -47,35 +48,22 @@ class ItemLocationBox(Box):
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return 0
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class ItemInfoEntry:
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"""A data class for one item described in an 'iinf' box."""
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def __init__(self, item_id, item_type, item_name):
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self.item_id = item_id
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self.type = item_type
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self.name = item_name
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def __repr__(self):
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return f"<ItemInfoEntry ID={self.item_id} type='{self.type}' name='{self.name}'>"
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class ItemInfoBox(Box):
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"""
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A specialized class for the 'iinf' box.
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Parses its own data to build a list of all available items.
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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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super().__init__(size, box_type, offset, raw_data)
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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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# 'iinf' is a FullBox, so the first 4 bytes are version/flags
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item_count = struct.unpack('>H', self.raw_data[4:6])[0]
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# The children are 'infe' boxes, which are parsed by the generic parser
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for infe_box in self.children:
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if infe_box.type == 'infe':
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# 'infe' is a FullBox (version, flags)
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# version = infe_box.raw_data[0]
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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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@@ -83,15 +71,118 @@ class ItemInfoBox(Box):
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self.entries.append(ItemInfoEntry(item_id, item_type, item_name))
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class PrimaryItemBox(Box):
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"""
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A specialized class for the 'pitm' 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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super().__init__(size, box_type, offset, raw_data)
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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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# 'pitm' is a FullBox (version, flags)
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self.item_id = struct.unpack('>H', self.raw_data[4:6])[0]
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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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return f"<ImageSpatialExtentsBox width={self.image_width} height={self.image_height}>"
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class ItemPropertyAssociationEntry:
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"""Helper class for an entry in the 'ipma' box."""
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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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def __repr__(self):
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return f"<ItemPropertyAssociationEntry item_id={self.item_id} associations={self.associations}>"
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class ItemPropertyAssociationBox(Box):
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"""'ipma' box, maps items to their properties."""
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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.entries: dict[int, ItemPropertyAssociationEntry] = {}
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self._parse_associations()
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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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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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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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"""'ipco' box. Just a container for property boxes like 'ispe'."""
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pass
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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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for child in self.children:
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if isinstance(child, ItemPropertyContainerBox):
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return child
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return None
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@property
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def ipma(self) -> ItemPropertyAssociationBox | None:
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"""Finds and returns the 'ipma' child box if it exists."""
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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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