Implemented a basic form of schema representation.

[~jspiros/python-ebml.git] / ebml / schema / base.py

diff --git a/ebml/schema/base.py b/ebml/schema/base.py
new file mode 100644 (file)
index 0000000..2686732
--- /dev/null
+++ b/ebml/schema/base.py
@@ -0,0 +1,202 @@
+__all__ = ('INT', 'UINT', 'FLOAT', 'STRING', 'UNICODE', 'DATE', 'BINARY', 'CONTAINER', 'Element', 'EBML')
+
+
+INT, UINT, FLOAT, STRING, UNICODE, DATE, BINARY, CONTAINER = range(0, 8)
+
+
+SCHEMA_TYPES = {
+       'int': INT,
+       'uint': UINT,
+       'float': FLOAT,
+       'string': STRING,
+       'date': DATE,
+       'binary': BINARY
+}
+
+
+class Element(object):
+       class_id = None
+       class_name = 'Unknown'
+       class_parents = ()
+       class_global = False
+       class_root = False
+       data_type = BINARY
+
+
+class EBMLElement(Element):
+       class_id = 0x1A45DFA3
+       class_name = 'EBML'
+       class_root = True
+       data_type = CONTAINER
+
+
+class EBMLVersionElement(Element):
+       class_id = 0x4286
+       class_name = 'EBMLVersion'
+       class_parents = (EBMLElement,)
+       data_type = UINT
+
+
+class EBMLReadVersionElement(Element):
+       class_id = 0x42F7
+       class_name = 'EBMLReadVersion'
+       class_parents = (EBMLElement,)
+       data_type = UINT
+
+
+class EBMLMaxIDLengthElement(Element):
+       class_id = 0x42F2
+       class_name = 'EBMLMaxIDLength'
+       class_parents = (EBMLElement,)
+       data_type = UINT
+
+
+class EBMLMaxSizeLengthElement(Element):
+       class_id = 0x42F3
+       class_name = 'EBMLMaxSizeLength'
+       class_parents = (EBMLElement,)
+       data_type = UINT
+
+
+class DocTypeElement(Element):
+       class_id = 0x4282
+       class_name = 'DocType'
+       class_parents = (EBMLElement,)
+       data_type = STRING
+
+
+class DocTypeVersionElement(Element):
+       class_id = 0x4287
+       class_name = 'DocTypeVersion'
+       class_parents = (EBMLElement,)
+       data_type = UINT
+
+
+class DocTypeReadVersionElement(Element):
+       class_id = 0x4285
+       class_name = 'DocTypeReadVersion'
+       class_parents = (EBMLElement,)
+       data_type = UINT
+
+
+class CRC32Element(Element):
+       class_id = 0xBF
+       class_name = 'CRC-32'
+       class_global = True
+       data_type = BINARY
+
+
+class VoidElement(Element):
+       class_id = 0xEC
+       class_name = 'Void'
+       class_global = True
+       data_type = BINARY
+
+
+class SignatureSlotElement(Element):
+       class_id = 0x1B538667
+       class_name = 'SignatureSlot'
+       class_global = True
+       data_type = CONTAINER
+
+
+class SignatureAlgoElement(Element):
+       class_id = 0x7E8A
+       class_name = 'SignatureAlgo'
+       class_parents = (SignatureSlotElement,)
+       data_type = UINT
+
+
+class SignatureHashElement(Element):
+       class_id = 0x7E9A
+       class_name = 'SignatureHash'
+       class_parents = (SignatureSlotElement,)
+       data_type = UINT
+
+
+class SignaturePublicKeyElement(Element):
+       class_id = 0x7EA5
+       class_name = 'SignaturePublicKey'
+       class_parents = (SignatureSlotElement,)
+       data_type = BINARY
+
+
+class SignatureElement(Element):
+       class_id = 0x7EB5
+       class_name = 'Signature'
+       class_parents = (SignatureSlotElement,)
+       data_type = BINARY
+
+
+class SignatureElementsElement(Element):
+       class_id = 0x7E5B
+       class_name = 'SignatureElements'
+       class_parents = (SignatureSlotElement,)
+       data_type = CONTAINER
+
+
+class SignatureElementListElement(Element):
+       class_id = 0x7E7B
+       class_name = 'SignatureElementList'
+       class_parents = (SignatureElementsElement,)
+       data_type = CONTAINER
+
+
+class SignedElementElement(Element):
+       class_id = 0x6532
+       class_name = 'SignedElement'
+       class_parents = (SignatureElementListElement,)
+       data_type = BINARY
+
+
+class Schema(object):
+       doc_type = None
+       version = None
+       elements_by_class_id = None
+       
+       @classmethod
+       def element_with_class_id(cls, class_id):
+               if cls.elements_by_class_id is None:
+                       cls.elements_by_class_id = {}
+                       for element in cls.elements:
+                               cls.elements_by_class_id[element.class_id] = element
+               return cls.elements_by_class_id[class_id]
+       
+       @classmethod
+       def global_elements(cls):
+               return [element for element in cls.elements if element.class_global]
+       
+       @classmethod
+       def root_elements(cls):
+               return [element for element in cls.elements if element.class_root]
+       
+       @classmethod
+       def child_elements_of_element(cls, parent):
+               children = [element for element in cls.elements if parent in element.class_parents]
+               children += cls.global_elements()
+               if 'self' in parent.class_parents and parent not in children:
+                       children.append(parent)
+               return children
+
+
+class EBML(Schema):
+       elements = (
+               EBMLElement,
+               EBMLVersionElement,
+               EBMLReadVersionElement,
+               EBMLMaxIDLengthElement,
+               EBMLMaxSizeLengthElement,
+               DocTypeElement,
+               DocTypeVersionElement,
+               DocTypeReadVersionElement,
+               CRC32Element,
+               VoidElement,
+               SignatureSlotElement,
+               SignatureAlgoElement,
+               SignatureHashElement,
+               SignaturePublicKeyElement,
+               SignatureElement,
+               SignatureElementsElement,
+               SignatureElementListElement,
+               SignedElementElement
+       )
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