X-Git-Url: http://git.ithinksw.org/~jspiros/python-ebml.git/blobdiff_plain/6147820602d99afa5862b7fced44fb47ae74bd17..3e0006c63000d5c09a9a09657806a6046cf6009d:/ebml/schema/specs.py

diff --git a/ebml/schema/specs.py b/ebml/schema/specs.py
new file mode 100644
index 0000000..7320b6b
--- /dev/null
+++ b/ebml/schema/specs.py
@@ -0,0 +1,74 @@
+from xml.etree.ElementTree import parse as parse_xml
+from .base import INT, UINT, FLOAT, STRING, UNICODE, DATE, BINARY, CONTAINER, Element, Schema
+
+
+SPECDATA_TYPES = {
+	'integer': INT,
+	'uinteger': UINT,
+	'float': FLOAT,
+	'string': STRING,
+	'utf-8': UNICODE,
+	'date': DATE,
+	'binary': BINARY,
+	'master': CONTAINER
+}
+
+
+def parse_specdata(source, schema_name):
+	"""
+	
+	Reads a schema specification from a file (e.g., specdata.xml) or file-like object, and returns a tuple containing:
+	
+		* a mapping of class names to Element subclasses
+		* a Schema subclass
+	
+	:arg source: the file or file-like object
+	:type source: str or file-like object
+	:arg schema_name: the name of the schema
+	:type schema_name: str
+	:returns: tuple
+	
+	"""
+	
+	tree = parse_xml(source)
+	elements = {}
+	parent_elements = []
+	
+	for element_element in tree.getiterator('element'):
+		raw_attrs = element_element.attrib
+		
+		element_name = '%sElement' % raw_attrs.get('cppname', raw_attrs.get('name'))
+		element_level = int(raw_attrs['level'])
+		element_attrs = {
+			'__module__': None,
+			'class_id': int(raw_attrs['id'], 0),
+			'class_name': raw_attrs['name'],
+			'data_type': SPECDATA_TYPES[raw_attrs['type']]
+		}
+		
+		while parent_elements and element_level <= parent_elements[-1][0]:
+			parent_elements.pop()
+		
+		if element_level == -1:
+			element_attrs['class_global'] = True
+			parent_elements = []
+		elif element_level == 0:
+			element_attrs['class_root'] = True
+			parent_elements = []
+		else:
+			if raw_attrs.get('recursive', '0') == '1':
+				element_attrs['class_parents'] = (parent_elements[-1][1], 'self')
+			else:
+				element_attrs['class_parents'] = (parent_elements[-1][1],)
+		
+		element = type(element_name, (Element,), element_attrs)
+		elements[element_name] = element
+		parent_elements.append((element_level, element))
+	
+	schema_attrs = {
+		'__module__': None,
+		'elements': tuple(elements.values())
+	}
+	schema = type(schema_name, (Schema,), schema_attrs)
+	
+	return elements, schema
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