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Merge pull request #3817 from elasota/oversized-probs-clarification

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Clarify that probability tables must not contain non-zero probabilities for invalid values
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Yann Collet
2024-01-13 11:37:54 -08:00
committed by GitHub
parent 7f76d37044 c5bf96fb74
commit 7971fd16f7
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doc/zstd_compression_format.md
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@@ -1124,6 +1124,9 @@ When last symbol reaches cumulated total of `1 << Accuracy_Log`,
decoding is complete. decoding is complete.
If the last symbol makes cumulated total go above `1 << Accuracy_Log`, If the last symbol makes cumulated total go above `1 << Accuracy_Log`,
distribution is considered corrupted. distribution is considered corrupted.
If this process results in a non-zero probability for a value outside of the
valid range of values that the FSE table is defined for, even if that value is
not used, then the data is considered corrupted.
Then the decoder can tell how many bytes were used in this process, Then the decoder can tell how many bytes were used in this process,
and how many symbols are present. and how many symbols are present.