[GRASS-dev] [GRASS GIS] #2750: LZ4 when writing raster rows; better than double I/O bound r.mapcalc speed

[GRASS GIS]

#2750: LZ4 when writing raster rows; better than double I/O bound r.mapcalc speed
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  Reporter:  sprice       |      Owner:  grass-dev@…
      Type:  enhancement  |     Status:  new
  Priority:  normal       |  Milestone:  7.1.0
 Component:  Raster       |    Version:  svn-trunk
Resolution:               |   Keywords:  ZLIB LZ4 ZSTD
       CPU:  OSX/Intel    |   Platform:  MacOSX
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Comment (by sprice):

 I considered writing a more general function for compression but I held
 off for two reasons:

 1) There seems to be a lot of very specific code depending on exactly what
 you're doing. For example, for read_data_fp_compressed() there was
 functionality hidden in G_zlib_read to save a header for each compressed
 row. Or the use of G_ZLIB_COMPRESSED_NO ('0') as a flag for FP
 compression, vs various integers defining CELL compression. To keep
 backwards compatibility, I delt with the different formats (CELL vs NULL
 vs FCELL/DCELL) on a case-by-case basis.

 2) I'm not familiar with the best practices for the code in GRASS GIS. I'd
 encourage someone else to create new files (or libraries) as required. I
 can help as required, but I'm concerned that as each edge case is
 considered (as mentioned above) there won't be all that much common code
 between the various compression uses.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2750#comment:15>
GRASS GIS <https://grass.osgeo.org>