Header
SegVersion
SegSize
IsCompoundFile
Diagnostics
Files
Attributes
IndexSort
Footer
Created.major
Created.minor
Created.bugfix
标志位
Min.major
Min.minor
Min.bugfix
NumSortFields
SortedField
SortedField
... ...
FieldName
SortTypeID
Selector
NumericType
Selector
Reverse
缺失值标志位
缺失值
SortTypeID = 5
SortTypeID = 6
索引文件.si