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wiki:decompress_UA
Last modified 18 months ago Last modified on 03/25/12 13:09:18

# Earthworm Module: decompress_UA

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## Function

The compress_UA and decompress_UA modules implement the gencompress algorithm which is used with permission from Boulder Real Time Technologies, Inc., copyright 1997.

## Details

The compress_UA and decompress_UA modules implement the gencompress algorithm which is used with permission from Boulder Real Time Technologies, Inc., copyright 1997.

compress_UA inputs selected trace data messages (TYPE_TRACEBUF), compresses the samples via the BRTT algorithm, leaves the header intact, and outputs the resulting message as TYPE_TRACE_COMP_UA. Trace messages are selected via SCN names listed in the .d file. Wildcards are allowed. The compressed data output can be tagged with compress_UA's installation_id and module_id (normal Earthworm behavior), or with the installation_id and module_id of the original uncompressed message.

Decompress_UA is the matching decompressor. Its output is identical to the input to the compressor. As with compress_UA, decompress_UA's output can be tagged with its own installation_id and module_id, or with those of the original message. This option allows the logo of the original data source to be preserved thru the compress/decompress operation.

In order to run compress_UA and decompress_UA, you must add TYPE_TRACE_COMP_UA message to 'earthworm.d'.

### Example Configuration File

    #
    #          Configuration File for decompress
    #
    MyModId     MOD_DECOMPRESS_UA   # This instance of pick_ew
    InRing              COMP_RING   # Transport ring to find compressed data on,
    OutRing             WAVE_RING   # Transport ring to write output to,
    HeartBeatInterval   15          # Heartbeat interval, in seconds,
    LogFile             1           # 0=write log to stderr/stdout, not to disk
                                    # 1=write a log file to disk
                                    # 2=write a module log but not to stderr/stdout

    GetWavesFrom  INST_WILDCARD MOD_WILDCARD  # only looks for msgtype:TYPE_TRACE_COMP_UA

    UseOriginalLogo     0           # 0=use decompress_UA's logo on outgoing TYPE_TRACEBUF msgs
                                    # non-zero=use instid&modid of original compressed msg
                                    #          on outgoing TYPE_TRACEBUF msg

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