ebml/schema/base.py

   1 __all__ = ('INT', 'UINT', 'FLOAT', 'STRING', 'UNICODE', 'DATE', 'BINARY', 'CONTAINER', 'Element', 'EBML')
   2
   3
   4 INT, UINT, FLOAT, STRING, UNICODE, DATE, BINARY, CONTAINER = range(0, 8)
   5
   6
   7 SCHEMA_TYPES = {
   8         'int': INT,
   9         'uint': UINT,
  10         'float': FLOAT,
  11         'string': STRING,
  12         'date': DATE,
  13         'binary': BINARY
  14 }
  15
  16
  17 class Element(object):
  18         class_id = None
  19         class_name = 'Unknown'
  20         class_parents = ()
  21         class_global = False
  22         class_root = False
  23         data_type = BINARY
  24
  25
  26 class EBMLElement(Element):
  27         class_id = 0x1A45DFA3
  28         class_name = 'EBML'
  29         class_root = True
  30         data_type = CONTAINER
  31
  32
  33 class EBMLVersionElement(Element):
  34         class_id = 0x4286
  35         class_name = 'EBMLVersion'
  36         class_parents = (EBMLElement,)
  37         data_type = UINT
  38
  39
  40 class EBMLReadVersionElement(Element):
  41         class_id = 0x42F7
  42         class_name = 'EBMLReadVersion'
  43         class_parents = (EBMLElement,)
  44         data_type = UINT
  45
  46
  47 class EBMLMaxIDLengthElement(Element):
  48         class_id = 0x42F2
  49         class_name = 'EBMLMaxIDLength'
  50         class_parents = (EBMLElement,)
  51         data_type = UINT
  52
  53
  54 class EBMLMaxSizeLengthElement(Element):
  55         class_id = 0x42F3
  56         class_name = 'EBMLMaxSizeLength'
  57         class_parents = (EBMLElement,)
  58         data_type = UINT
  59
  60
  61 class DocTypeElement(Element):
  62         class_id = 0x4282
  63         class_name = 'DocType'
  64         class_parents = (EBMLElement,)
  65         data_type = STRING
  66
  67
  68 class DocTypeVersionElement(Element):
  69         class_id = 0x4287
  70         class_name = 'DocTypeVersion'
  71         class_parents = (EBMLElement,)
  72         data_type = UINT
  73
  74
  75 class DocTypeReadVersionElement(Element):
  76         class_id = 0x4285
  77         class_name = 'DocTypeReadVersion'
  78         class_parents = (EBMLElement,)
  79         data_type = UINT
  80
  81
  82 class CRC32Element(Element):
  83         class_id = 0xBF
  84         class_name = 'CRC-32'
  85         class_global = True
  86         data_type = BINARY
  87
  88
  89 class VoidElement(Element):
  90         class_id = 0xEC
  91         class_name = 'Void'
  92         class_global = True
  93         data_type = BINARY
  94
  95
  96 class SignatureSlotElement(Element):
  97         class_id = 0x1B538667
  98         class_name = 'SignatureSlot'
  99         class_global = True
 100         data_type = CONTAINER
 101
 102
 103 class SignatureAlgoElement(Element):
 104         class_id = 0x7E8A
 105         class_name = 'SignatureAlgo'
 106         class_parents = (SignatureSlotElement,)
 107         data_type = UINT
 108
 109
 110 class SignatureHashElement(Element):
 111         class_id = 0x7E9A
 112         class_name = 'SignatureHash'
 113         class_parents = (SignatureSlotElement,)
 114         data_type = UINT
 115
 116
 117 class SignaturePublicKeyElement(Element):
 118         class_id = 0x7EA5
 119         class_name = 'SignaturePublicKey'
 120         class_parents = (SignatureSlotElement,)
 121         data_type = BINARY
 122
 123
 124 class SignatureElement(Element):
 125         class_id = 0x7EB5
 126         class_name = 'Signature'
 127         class_parents = (SignatureSlotElement,)
 128         data_type = BINARY
 129
 130
 131 class SignatureElementsElement(Element):
 132         class_id = 0x7E5B
 133         class_name = 'SignatureElements'
 134         class_parents = (SignatureSlotElement,)
 135         data_type = CONTAINER
 136
 137
 138 class SignatureElementListElement(Element):
 139         class_id = 0x7E7B
 140         class_name = 'SignatureElementList'
 141         class_parents = (SignatureElementsElement,)
 142         data_type = CONTAINER
 143
 144
 145 class SignedElementElement(Element):
 146         class_id = 0x6532
 147         class_name = 'SignedElement'
 148         class_parents = (SignatureElementListElement,)
 149         data_type = BINARY
 150
 151
 152 class Schema(object):
 153         doc_type = None
 154         version = None
 155         elements_by_class_id = None
 156
 157         @classmethod
 158         def element_with_class_id(cls, class_id):
 159                 if cls.elements_by_class_id is None:
 160                         cls.elements_by_class_id = {}
 161                         for element in cls.elements:
 162                                 cls.elements_by_class_id[element.class_id] = element
 163                 return cls.elements_by_class_id[class_id]
 164
 165         @classmethod
 166         def global_elements(cls):
 167                 return [element for element in cls.elements if element.class_global]
 168
 169         @classmethod
 170         def root_elements(cls):
 171                 return [element for element in cls.elements if element.class_root]
 172
 173         @classmethod
 174         def child_elements_of_element(cls, parent):
 175                 children = [element for element in cls.elements if parent in element.class_parents]
 176                 children += cls.global_elements()
 177                 if 'self' in parent.class_parents and parent not in children:
 178                         children.append(parent)
 179                 return children
 180
 181
 182 class EBML(Schema):
 183         elements = (
 184                 EBMLElement,
 185                 EBMLVersionElement,
 186                 EBMLReadVersionElement,
 187                 EBMLMaxIDLengthElement,
 188                 EBMLMaxSizeLengthElement,
 189                 DocTypeElement,
 190                 DocTypeVersionElement,
 191                 DocTypeReadVersionElement,
 192                 CRC32Element,
 193                 VoidElement,
 194                 SignatureSlotElement,
 195                 SignatureAlgoElement,
 196                 SignatureHashElement,
 197                 SignaturePublicKeyElement,
 198                 SignatureElement,
 199                 SignatureElementsElement,
 200                 SignatureElementListElement,
 201                 SignedElementElement
 202         )