VTD

Virtual Token Descriptor (VTD) is a binary format describing XML tokens non-extractively. VTD records require that XML document be maintained intact in memory. The VTD record layout further specifies the following: Use 64 bits as the primitive type (b63~b0) Starting offset: 30 bits (b29 ~ b0) maximum value is 2^30 -1 = 1G -1 Length: 20 bits (b51 ~ b32) maximum value is 2^20-1 = 1M -1 For some token type Prefix length: 9 bits (b51~ b43) max value 511 Q-name length: 11 bits (b42 ~ b 32) max value 1023 Depth: 8 bits (b59~b52) max value is 2^8-1 = 255 Token type: 4 bits (b63~b60) Reserved bit: 2 bits (b31: b30)
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