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# Utility variables

This are enum values which avoid the nuisance of remembering codes and IDs.

## Limits for different features

enumerator BLOSC_MIN_HEADER_LENGTH

  Minimum header length (Blosc1).

enumerator BLOSC_EXTENDED_HEADER_LENGTH

  Extended header length (Blosc2, see README_HEADER).

enumerator BLOSC2_MAX_OVERHEAD

  The maximum overhead during compression in bytes. This equals to BLOSC_EXTENDED_HEADER_LENGTH now, but can be higher in future implementations.

enumerator BLOSC_MIN_BUFFERSIZE

  Minimum buffer size to be compressed.

enumerator BLOSC2_MAX_BUFFERSIZE

  Maximum source buffer size to be compressed.

enumerator BLOSC_MAX_TYPESIZE

  Maximum typesize before considering source buffer as a stream of bytes. Cannot be larger than 255.

enumerator BLOSC2_MAX_FILTERS

  Maximum number of filters in the filter pipeline.

## Codes for filters

enumerator BLOSC_NOSHUFFLE

  No shuffle (for compatibility with Blosc1).

enumerator BLOSC_NOFILTER

  No filter.

enumerator BLOSC_SHUFFLE

  Byte-wise shuffle. `filters_meta` does not have any effect here.

enumerator BLOSC_BITSHUFFLE

  Bit-wise shuffle. `filters_meta` does not have any effect here.

enumerator BLOSC_DELTA

  Delta filter. `filters_meta` does not have any effect here.

enumerator BLOSC_TRUNC_PREC

  Truncate mantissa precision. Positive values in `filters_meta` will keep bits; negative values will zero bits.

enumerator BLOSC_FILTER_NDCELL

  Simple filter for grouping NDim cell data together. See Blosc/c-blosc2

enumerator BLOSC_FILTER_NDMEAN

  Simple filter for replacing content of a NDim cell with its mean value. See Blosc/c-blosc2

enumerator BLOSC_FILTER_BYTEDELTA

  Byteshuffle + delta. The typesize should be specified in the `filters_meta` slot. Sometimes this can represent an advantage over BLOSC_SHUFFLE or BLOSC_BITSHUFFLE. See https://www.blosc.org/posts/bytedelta-enhance-compression-toolset/

enumerator BLOSC_FILTER_INT_TRUNC

  Truncate int precision; positive values in `filters_meta` slot will keep bits; negative values will remove (set to zero) bits. This is similar to BLOSC_TRUNC_PREC, but for integers instead of floating point data.

## Compressor codecs

enumerator BLOSC_BLOSCLZ

enumerator BLOSC_LZ4

enumerator BLOSC_LZ4HC

enumerator BLOSC_ZLIB

enumerator BLOSC_ZSTD

enumerator BLOSC_CODEC_NDLZ

  Simple Lempel-Ziv compressor for NDim data. Experimental, mainly for teaching purposes.

enumerator BLOSC_CODEC_ZFP_FIXED_ACCURACY

  ZFP compressor for fixed accuracy mode. The desired accuracy is set in `compcode_meta`. See Blosc/c-blosc2

enumerator BLOSC_CODEC_ZFP_FIXED_PRECISION

  ZFP compressor for fixed precision. The desired precision is set in `compcode_meta`. See Blosc/c-blosc2

enumerator BLOSC_CODEC_ZFP_FIXED_RATE

  ZFP compressor for fixed precision. The desired rate is set in `compcode_meta`. See Blosc/c-blosc2

enumerator BLOSC_CODEC_OPENHTJ2K

  OpenHTJ2K compressor for JPEG 2000 HT. See Blosc/blosc2_openhtj2k

enumerator BLOSC_CODEC_GROK

  Grok compressor for JPEG 2000. See Blosc/blosc2_grok

## Compressor names

BLOSC_BLOSCLZ_COMPNAME "blosclz"

BLOSC_LZ4_COMPNAME "lz4"

BLOSC_LZ4HC_COMPNAME "lz4hc"

BLOSC_ZLIB_COMPNAME "zlib"

BLOSC_ZSTD_COMPNAME "zstd"

## Internal flags (blosc1_cbuffer_metainfo)

enumerator BLOSC_DOSHUFFLE

  byte-wise shuffle

enumerator BLOSC_MEMCPYED

  plain copy

enumerator BLOSC_DOBITSHUFFLE

  bit-wise shuffle

enumerator BLOSC_DODELTA

  delta coding