Fix UTF-8 decoding of lazy bytestrings #333
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I don't understand the doctest errors on GHC 8+, and on GHC 7+ the errors are that old versions of bytestring did not have |
Bodigrim
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May 6, 2021
Lysxia
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There's one uncovered branch because the tests only use an
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That's probably fine, I guess. Looks good to me except GHC < 7.6 builds. |
Bodigrim
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May 8, 2021
Bodigrim
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May 12, 2021
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(Found a silly space.) |
Bodigrim
previously approved these changes
May 12, 2021
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@Lysxia could you please resolve a conflict? |
At the beginning of a new chunk we may be trying to complete a UTF-8 sequence started in the previous chunk (contained in the `undecode0` buffer). If it turns out to be invalid, we must apply the `onErr` handler to every character in that buffer. When we reach the end of the chunk, we must also be more careful about when to keep the previous buffer: a UTF-8 sequence (up to 4 bytes) can span more than two chunks, when those chunks are very short (of length 0, 1, or 2).
Bodigrim
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May 22, 2021
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Fixes #330.
I found another issue that's not yet fixed: both strict and lazy
decodeUtf8Withare actually memory unsafe if you use a badonErrargument. We allocate a destination buffer with 2x the number of bytes from the original bytestrings, but by using anonErrfunction which replaces any invalid byte with aCharwhich is a surrogate pair in UTF-16, it possible to blow up the size taken by aTextto 4x. In practice,onErris almost alwayslenientDecodethough, so perhaps a better solution than allocating more memory is to either hidedecodeUtf8Withor clamp the range ofonErr.