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