org.saddle.binary

Binary serialization for Frame[String,String,T] or Mat[T] with primitive T

The layout of binary format is as follows:

• The first 6 bytes are "SADDLE"
• The next unsigned byte is the major version
• The next unsigned byte is the minor version
• The next 4 bytes form a little endian integer as HEADER_LENGTH
• The next HEADER_LENGTH bytes form an UTF-8 string as the header.
• The header is a valid JSON object with the following fields:
  • v: numeric positive integer is the version of the header structure
  • colix : a JSON array of strings, it is the column index of the frame
  • rowix : a JSON array of strings, it is the row index of the frame
  • numrows: numeric positive integer, number of rows
  • numcols: numeric positive integer, number of cols
  • Either one of rowix or numrows may be missing
  • Either one of colix or numcols may be missing
  • rowmajor : a boolean, indicating whether the data is stored in row-major or col-major order
  • datatype : string, either "double", "long", "int", "float", "byte"
• The header is padded with spaces (0x20) such that HEADER_LENGTH+12 is divisible by 16. The count of spaces are included in HEADER_LENGTH.
• The next width * numRows * numCols bytes form a little endian primitive array in row-major or col-major order. numRows and numCols are determined from the rowix/numrows and colix/numcols header fields. width is determined from the datatype field (8 for double and long, 4 for int and float, 1 for byte)