Variable-to-fixed length source code. Builds a byte-alphabet dictionary by repeatedly splitting the highest-probability phrase into its 256 one-byte extensions, producing a set of variable-length input phrases that are each mapped to one fixed-width codeword.
| Property | Value |
|---|---|
| Category | Compression Algorithms |
| Sub-category | Variable-to-Fixed Coding |
| Security status | Not classified |
| Complexity | Advanced |
| Inventor | Brian Parker Tunstall |
| Year | 1967 |
| Origin | 🇺🇸 United States |
| Source | algorithms/compression/tunstall.js |
Status: not classified — treat as unverified.
No vulnerabilities are recorded for this implementation.
4 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — Empty input
| Field | Value |
|---|---|
input |
(empty) |
expected |
00000000 |
Vector 2 — Repetitive input - all zero bytes
| Field | Value |
|---|---|
input |
0000000000000000 |
expected |
08000000080000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 … (1040 bytes; the full value is in the source) |
Vector 3 — Text sample - ‘ABAAAB’
| Field | Value |
|---|---|
input |
414241414142 |
expected |
06000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 … (1031 bytes; the full value is in the source) |
Vector 4 — Text sample - pangram sentence
| Field | Value |
|---|---|
input |
74686520717569636b2062726f776e20 666f78206a756d7073206f7665722074 6865206c617a7920646f67 |
expected |
2b000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 … (1066 bytes; the full value is in the source) |