Let a base64 decoder be told where its input ends - #377
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gennaroprota merged 1 commit intoAug 14, 2026
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Decoding base64 means turning 6 bit input into 8 bit output, and a sequence whose length is not a whole number of four character groups ends with bits which do not make up a byte. `equal_impl` promises to discard them, but for `BitsIn < BitsOut` it only compares base iterators, so the caller sees one more element to fetch and `fill()` looks for the missing bits beyond the end of the input. Any length with `n % 4 == 1` does it. Reading the input is the only way the single argument constructor learns where it ends, so it cannot avoid this. The new constructor takes the end as well, and then a value which cannot be completed ends the sequence rather than being sought. The old form keeps its behavior. Fixes #324.
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Decoding base64 means turning 6 bit input into 8 bit output, and a sequence whose length is not a whole number of four character groups ends with bits which do not make up a byte.
equal_implpromises to discard them, but forBitsIn < BitsOutit only compares base iterators, so the caller sees one more element to fetch andfill()looks for the missing bits beyond the end of the input. Any length withn % 4 == 1does it.Reading the input is the only way the single argument constructor learns where it ends, so it cannot avoid this. The new constructor takes the end as well, and then a value which cannot be completed ends the sequence rather than being sought. The old form keeps its behavior.
Fixes #324.