Merge branch 'master' of feistymeow.org:feisty_meow

[feisty_meow.git] / scripts / testing / test_assoc_array.sh

diff --git a/scripts/testing/test_assoc_array.sh b/scripts/testing/test_assoc_array.sh
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+#!/bin/bash
+
+##############
+
+# simple examples...
+
+declare -A snuggles
+  # make an associative array
+
+snuggles=([book]=petunia [muffets]="glasgow robbery")
+  # keys: book and muffets
+  # values: (second part)
+
+snuggles+=([morgower]=flimshaw)
+  # adding entries to it.
+
+echo ${!snuggles[x]}
+  # show index x's key.
+
+echo ${snuggles[x]}
+  # show index x's value.
+
+##############
+
+# excellent code from:
+# http://blog.spencertipping.com/2009/08/constant-time-associative-arrays-in-bash
+ 
+typeset -a table_keys
+typeset -a table_values
+ 
+function index_of_key () {
+  initial=$(($(echo $1 | md5sum | cut -c 18-32 | awk '{print "0x"$1}')))
+  while [[ ${table_keys[$initial]} && ${table_keys[$initial]} != $1 ]]; do
+    initial=$((initial + 1))
+  done
+  echo -n $initial
+}
+ 
+function associate () {
+  index=$(index_of_key $1)
+  table_keys[$index]=$1
+  table_values[$index]=$2
+  echo -n $2
+}
+ 
+function lookup () {
+  index=$(index_of_key $1)
+  echo -n ${table_values[$index]}
+}
+ 
+echo Associating foo with bar and bif with baz
+associate foo bar && echo
+associate bif baz && echo
+ 
+echo -n Looking up foo:
+lookup foo && echo
+ 
+echo -n Looking up bif:
+lookup bif && echo
+ 
+echo -n Looking up bar:
+lookup bar && echo
+
+##############
+