Examples

Complete SDDL descriptions for real binary formats.

SAO Star Catalog (Simplified)

The Silesia compression corpus includes a file from the SAO (Smithsonian Astronomical Observatory) star catalog. This simplified description treats every entry as having the same fixed layout — 28 bytes of coordinates, spectral type, magnitude, and proper motion:

Record StarEntry() = {
  SRA0:  Float64LE,     # Right Ascension (radians)
  SDEC0: Float64LE,     # Declination (radians)
  ISP:   Bytes(2),      # Spectral type
  MAG:   Int16LE,       # Magnitude
  XRPM:  Float32LE,     # R.A. proper motion
  XDPM:  Float32LE      # Dec. proper motion
}

header: Byte[28]
stars: StarEntry[]

This works well when the file uses a single fixed entry format. For the full SAO format with variable-layout entries, see the Getting Started guide.