fn decode_number(word: &str) -> Option<u64>Expand description
Decodes a base64-like encoded number from the StarDict/dictd .index format.
.index files encode byte offsets and sizes as base-64 positional numbers
rather than plain integers. Each character encodes 6 bits:
| Characters | Values |
|---|---|
A–Z | 0–25 |
a–z | 26–51 |
0–9 | 52–61 |
+ | 62 |
/ | 63 |
The decoded u64 is a byte position (offset) or length (size) that the
dictionary reader uses to seek() directly to the right location in the
dictionary data file.
Returns None if any character falls outside the encoding alphabet.