Plugin: hexnumber

• infos = Information about the hexnumber plugin is in keys below
• infos/author = Klemens Böswirth k.boe.nosp@m.swir.nosp@m.th+gi.nosp@m.t@gm.nosp@m.ail.c.nosp@m.om
• infos/licence = BSD
• infos/needs =
• infos/provides = conv check
• infos/recommends =
• infos/placements = postgetstorage presetstorage
• infos/status = maintained unittest nodep configurable
• infos/metadata = unit/base
• infos/ordering = type
• infos/description = converts hexadecimal values into decimal and back

Introduction

This plugin is used to read configuration files that use hexadecimal values. All "hex-values" (see below) will be converted into decimal when Elektra reads values from the mounted file. When Elektra writes back to the file the converted values will be converted back and stored as before (0X will be replaced with 0x).

Installation

See installation. The package is called libelektra5-extra.

What are "hex-values"?

There are multiple ways you can signal to the hexnumber plugin, that a value should be converted:

1. If a Key has the metadata unit/base set to hex it will always be interpreted as a hex-value. The plugin will also produce an error, if the value contained in such a Key does not start with 0x (or 0X).
2. If unit/base is not present and
   • the type metadata is set to one of the recognized integer-types (default: byte, short, unsigned_short, long, unsigned_long, long_long, unsigned_long_long)
   • AND the configuration value itself starts with 0x (or 0X) it will be interpreted as a hex-value.
3. If forced conversion mode (/force plugin configuration, see below) is enabled all values starting with 0x (or 0X) are considered hex-values.

Configuration

When mounting a backend with the hexnumber plugin, a few settings can be configured.

1. To enable forced conversion mode set /force to any value. In forced conversion mode the plugin tries to convert ALL strings starting with 0x (or 0X) into decimal before passing the value on to the rest of Elektra. This can be useful for importing a configuration file that uses hexadecimal values into Elektra without writing a specification for the file.

   NOTE: be careful when using this option, as any configuration value that contains invalid non-hexadecimal characters (i.e. does not match 0[xX][0-9A-Fa-f]+) will result in an error.

sudo kdb mount test.ecf /examples/hexnumber/forced hexnumber /force=1

1. The types recognized as integers can be configured. For this purpose specify all additional types you want to be considered for possible hexadecimal conversion as an Elektra array. All keys with a type from /accept/types/#, or one of the default types, will be converted to hexadecimal if the value starts with 0x (or 0X).

sudo kdb mount test.ecf /examples/hexnumber/customtypes hexnumber /accept/types/#0=customint /accept/types/#1=othercustomint

Usage & Example

• To mount a simple backend that uses hexadecimal numbers, you can use:

  sudo kdb mount test.ecf user:/tests/hexnumber hexnumber

• A few examples on how to use the plugin:

# Example 1: read hex value
kdb set user:/tests/hexnumber/hex 0x1F
kdb meta-set user:/tests/hexnumber/hex type long
 
kdb get user:/tests/hexnumber/hex
#> 31
 
# Example 2: decimal value not converted
kdb set user:/tests/hexnumber/dec 26
kdb meta-set user:/tests/hexnumber/dec type long
 
kdb get user:/tests/hexnumber/dec
#> 26
 
# Example 3: string untouched
kdb set user:/tests/hexnumber/string value
kdb meta-set user:/tests/hexnumber/string type string
 
kdb get user:/tests/hexnumber/string
#> value
 
# Example 4: read hex value with unit/base
kdb set user:/tests/hexnumber/hex2 0xF
kdb meta-set user:/tests/hexnumber/hex2 unit/base hex
 
kdb get user:/tests/hexnumber/hex2
#> 15
 
# Undo changes
kdb rm -r user:/tests/hexnumber

• To unmount the plugin use the following command:

  kdb umount user:/tests/hexnumber
  #>