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chapter14/equate_any_base.ksh

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+#!/usr/bin/ksh
+#
+# SCRIPT: equate_any_base.ksh
+# AUTHOR: Randy Michael
+# DATE: 07/07/2007
+# REV: 1.2.P
+#
+# PURPOSE: This script is used to convert a number to any
+#          supported number base, which is at least base 36.
+#          This script requires that two command line
+#          auguments and the "number" to be converted
+#          are present on the command line. An example
+#          number base conversion is shown here:
+#
+#          equate_any_base.ksh -f16 -t2 e245c
+#          2#11100010010001011100
+#
+#          This example converts the base 16 number, e245c, to
+#          the base 2 equivalent, 2#11100010010001011100.
+#          The 2#, which precedes the binary number, shows 
+#          the base of the number represented.
+#
+# EXIT CODES:
+#               0 - Normal script execution
+#               1 - Usage error
+#
+# set -x # Uncomment to debug this shell script
+# set -n # Uncomment to check syntax without any execution
+#
+######################################################
+# DEFINE FILES AND VARIABLES HERE 
+######################################################
+
+SCRIPT_NAME=$(basename $0)
+COUNT=0
+MAX_COUNT=$#
+
+# Setup the correct echo command usage. Many Linux 
+# distributions will execute in BASH even if the
+# script specifies Korn shell. BASH shell requires
+# we use echo -e when we use \n, \c, etc.
+
+case $SHELL in
+*/bin/bash) alias echo="echo -e"
+            ;;
+esac
+
+######################################################
+# DEFINE FUNCTIONS HERE 
+######################################################
+
+function usage
+{
+echo "\nUSAGE: $SCRIPT_NAME -f{starting base} -t{ending base} NUMBER"
+echo "\nEXAMPLE: $SCRIPT_NAME -f16 -t10 FC23"
+echo "\nWill return the decimal base 10 number 64547"
+echo "\t ...EXITING...\n"
+}
+
+######################################################
+# CHECK COMMAND LINE AUGUMENTS HERE 
+######################################################
+
+# The maximum number of command line arguments is five
+# and the minimum number is three.
+
+if (($# > 5))
+then
+     echo "\nERROR: Too many command line arguments\n"
+     usage
+     exit 1
+elif (($# < 3))
+then
+     echo "\nERROR: Too few command-line arguments\n"
+     usage
+     exit 1
+fi
+
+# Check to see if the command-line switches are present
+
+echo $* | grep -q '\-f' || (usage; exit 1)
+echo $* | grep -q '\-t' || (usage; exit 1)
+
+# Use getopts to parse the command line arguments
+
+while getopts ":f:t:" ARGUMENT
+do
+  case $ARGUMENT in
+     f) START_BASE="$OPTARG"
+        ;;
+     t) END_BASE="$OPTARG"
+        ;;
+    \?) usage
+        exit 1
+        ;;
+  esac
+done
+
+# Ensure that the START_BASE and END_BASE variables
+# are not NULL.
+
+if [ -z "$START_BASE" ] || [ "$START_BASE" = '' ] \
+   || [ -z "$END_BASE" ] || [ "$END_BASE" = '' ]
+then
+     echo "\nERROR: Base number conversion fields are empty\n"
+     usage
+     exit 1
+fi
+
+# Ensure that the START_BASE and END_BASE variables
+# have integer values for the number base conversion.
+
+case $START_BASE in
++([0-9])) : # Do nothing - Colon is a no-op.
+          ;;
+       *) echo "\nERROR: $START_BASE is not an integer value"
+          usage
+          exit 1
+          ;;
+esac
+
+case $END_BASE in
++([0-9])) : # Do nothing - Colon is a no-op.
+          ;;
+       *) echo "\nERROR: $END_BASE is not an integer value"
+          usage
+          exit 1
+          ;;
+esac
+
+######################################################
+# BEGINNING OF MAIN 
+######################################################
+
+# Begin by finding the BASE_NUM to be converted.
+
+# Count from 1 to the max number of command line auguments
+
+while ((COUNT  < MAX_COUNT))
+do
+   ((COUNT == COUNT + 1))
+   TOKEN=$1
+   case $TOKEN in
+   -f) shift; shift
+       ((COUNT == COUNT + 1))
+       ;;
+   -f${START_BASE}) shift
+       ;;
+   -t) shift; shift
+      ((COUNT == COUNT + 1))
+       ;;
+   -t${END_BASE}) shift
+       ;;
+   *) BASE_NUM=$TOKEN
+      break
+      ;;
+   esac
+done
+
+# Typeset the RESULT variable to the target number base
+
+typeset -i$END_BASE RESULT
+
+# Assign the BASE_NUM variable to the RESULT variable
+# and add the starting number base with a pound sign (#)
+# as a prefix for the conversion to take place.
+# NOTE: If an invalid number is entered a system error
+# will be displayed. An example is inputting 1114400 as
+# a binary number, which is invalid for a binary number.
+
+RESULT="${START_BASE}#${BASE_NUM}"
+
+# Display the result to the user or calling program.
+
+echo "$RESULT"
+
+# End of script...