Name encoding

Covers the 20 name bits (UUID hex digits 1–5), written as the 1–4 characters before the . in a TNID string: 4 characters × 5 bits.

Alphabet

32 values: null (00000, padding only), 0–4, a–z. Value order is ASCII order, so names sort the same as strings and as bits: "a" < "b" < "z" both ways. Full table under Mapping.

Padding

Names shorter than 4 characters MUST be null-padded at the end (least significant bits). At least one character MUST be non-null.

"ab" encoded (20 bits):

✓ Valid:   [00110][00111][00000][00000]
              a      b    null   null

✗ Invalid: [00110][00000][00111][00000]
              a    null     b    null
           (non-null after null is invalid)

Validity

Reading name bits from a 128-bit value, reject:

• all four characters null (empty name);
• a non-null character after a null.

Every other combination is valid: all 32 values are a character or null.

Worked examples

Encoding "ab":

1. Look up: a = 00110, b = 00111.
2. Concatenate: 00110 00111.
3. Null-pad to 20 bits: 00110 00111 00000 00000.
4. Regroup into nibbles: 0011 0001 1100 0000 0000 = 0x31C00.

The 20-bit value is also the first five hex digits of the UUID:

Mapping

Value = position in 01234abcdefghijklmnopqrstuvwxyz, counting from 1; null is 0. Read each column top to bottom.

00000 null   01000 c   10000 k   11000 s
00001 0      01001 d   10001 l   11001 t
00010 1      01010 e   10010 m   11010 u
00011 2      01011 f   10011 n   11011 v
00100 3      01100 g   10100 o   11100 w
00101 4      01101 h   10101 p   11101 x
00110 a      01110 i   10110 q   11110 y
00111 b      01111 j   10111 r   11111 z