Data.Word.Base62

This module provides functions for encoding fixed-width words using the base-62 encoding scheme. The encoding functions in this module produce byte sequences that are ASCII-compatible text encodings (e.g. ISO-8859-1 and UTF-8). Similarly, the decoding functions only decode byte sequences that are an ASCII-compatible text encoding of characters in the class [A-Za-Z0-9]. Other encodings (notably UTF-16) are not supported but would be accepted in a pull request.

64-bit Word

encode64 :: Word64 -> ByteArray

Base62 encode a 64-bit word. Leading zero bits are suppressed.

>>> putStrLn (Bytes.toLatinString (Bytes.fromByteArray (encode64 213635)))
tZj

Note that this will encode the number 0 as the character 0 rather than as the empty byte array.

builder64 :: Word64 -> Builder 11

Base62 encode a 64-bit word as a builder.

decode64 :: Bytes -> Maybe Word64

Decode a base62-encoded 64-bit word. This rejects the empty string rather than decoding it as zero. This also rejects encoded numbers greater than or equal to 2^64.

>>> decode64 (Bytes.fromAsciiString "LygHa16AHYB")
Just 18446744073709551611
>>> decode64 (Bytes.fromAsciiString "1IdHllabYuAOlNK4")
Nothing

128-bit Word

encode128 :: Word128 -> ByteArray

Base62 encode a 128-bit word. Leading zero bits are suppressed.

>>> let octillion = 1_000_000_000_000_000_000_000_000_000
>>> putStrLn (Bytes.toLatinString (Bytes.fromByteArray (encode128 octillion)))
1IdHllabYuAOlNK4

builder128 :: Word128 -> Builder 22

Base62 encode a 128-bit word as a builder.

decode128 :: Bytes -> Maybe Word128

Decode a base62-encoded 128-bit word. This rejects the empty string rather than decoding it as zero. This also rejects encoded numbers greater than or equal to 2^128.

>>> decode128 (Bytes.fromAsciiString "LygHa16AHYB")
Just 18446744073709551611
>>> decode128 (Bytes.fromAsciiString "7n42DGM5Tflk9n8mt7Fhc6")
Just 340282366920938463463374607431768211454
>>> decode128 (Bytes.fromAsciiString "7n42DGM5Tflk9n8mt7Fhc9")
Nothing