The Ion 1.1 Draft Specification

Integers

Opcodes in the range 0x60 to 0x68 represent an integer. The opcode is followed by a FixedInt that represents the integer value. The low nibble of the opcode (0x_0 to 0x_8) indicates the size of the FixedInt. Opcode 0x60 represents integer 0; no more bytes follow.

Integers that require more than 8 bytes are encoded using the variable-length integer opcode 0xF6, followed by a <<flexuint, FlexUInt>> indicating how many bytes of representation data follow.

0xEB 0x01 represents null.int.

Encoding of integer 0

┌──── Opcode in 60-68 range indicates integer
│┌─── Low nibble 0 indicates
││    no more bytes follow.
60

Encoding of integer 17

┌──── Opcode in 60-68 range indicates integer
│┌─── Low nibble 1 indicates
││    a single byte follows.
61 11
    └── FixedInt 17

Encoding of integer -944

┌──── Opcode in 60-68 range indicates integer
│┌─── Low nibble 2 indicates
││    that two bytes follow.
62 50 FC
   └─┬─┘
FixedInt -944

Encoding of integer -944

┌──── Opcode F6 indicates a variable-length integer, FlexUInt length follows
│   ┌─── FlexUInt 2; a 2-byte FixedInt follows
│   │
F6 05 50 FC
      └─┬─┘
   FixedInt -944

Encoding of null.int

┌──── Opcode 0xEB indicates a typed null; a byte follows specifying the type
│  ┌─── Null type: integer
│  │
EB 01