Support blosc 'shuffle' of -1 in v2 metadata - #102
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normanrz merged 2 commits intoSep 9, 2026
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Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Blosc's -1 means bit shuffle for single-byte items and byte shuffle otherwise. Since numcodecs omits 'typesize' from the .zarray metadata, the item size is only known once the data type has been read, so the variant is derived again when the codec is evolved. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Zarr v2 arrays written by other implementations may have
"shuffle": -1(blosc picks the variant at write time). Reading them failed withArrayIndexOutOfBoundsExceptionfromShuffle.values()[-1].The actual variant is stored in the chunk header, so decoding is unaffected;
-1now maps toBYTE_SHUFFLE, and other unknown values give a readable parse error.🤖 Generated with Claude Code