Zarr v.2 checksum filters

The "crc32", "adler32" and "fletcher32" filters add a 32-bit checksum to the data, in little-endian byte order. The "crc32" and "adler32" checksums are placed at the start of the data unless the configuration has a location of "end"; the "fletcher32" checksum is always placed at the end. Decoding strips the checksum and verifies it against the data: if the two don't match a warning is generated.

The "fletcher32" checksum is the HDF5 variant. The two 16-bit sums are verified modulo 65535 because the HDF5 algorithm does not reduce a sum of 65535 to 0.

Super classes

zarr_extension -> zarr_codec -> zarr_filter -> zarr_filter_checksum

Methods

Public methods

• zarr_filter_checksum$new()

• zarr_filter_checksum$decode()

Inherited methods

• zarr_codec$metadata_fragment()
• zarr_codec$print()
• zarr_filter$copy()
• zarr_filter$encode()

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zarr_filter_checksum$new()

Create a new checksum filter.

Usage

zarr_filter_checksum$new(id, configuration = list())

Arguments

id

The Numcodecs identifier of the filter, one of "crc32", "adler32" or "fletcher32".

configuration

A list with the configuration parameters of the filter, optionally with element location for "crc32" and "adler32".

Returns

An instance of this class.

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zarr_filter_checksum$decode()

Strip the checksum from the data and verify it.

Usage

zarr_filter_checksum$decode(data)

Arguments

data

The encoded data, a raw vector.

Returns

A raw vector with the decoded data.