rand: --fmt FORMAT implemented.

rand/rand

@@ -10,7 +10,7 @@ rand - generate (pseudo-)random data
 
 =head1 SYNOPSIS
 
-B<rand> [[I<from>] I<to>]
+B<rand> [-f FORMAT|--format FORMAT] [[I<from>] I<to>]
 
 
 =head1 DESCRIPTION
@@ -27,6 +27,19 @@ If I<to> is given, numbers will be integers from 0 to I<to>.
 If I<from> is also given, numbers will be integers from I<from> to I<to>.
 
 
+=head1 OPTIONS
+
+=over 4
+
+=item B<--format> I<FORMAT>
+
+=item B<-f> I<FORMAT>
+
+Format number using I<FORMAT>. I<FORMAT> follows B<printf>s specification.
+
+=back
+
+
 =head1 EXAMPLE
 
 Overwrite a harddisk with random data:
@@ -41,9 +54,16 @@ Overwrite a harddisk with random data:
   rand 1000 1999 | head -n 100
 
 
+=head1 EXAMPLE
+
+100 random numbers from 256 to 65535 in hex with 0s prepended:
+
+  rand -f '%04x\n' 256 65535 | head -n 100
+
+
 =head1 AUTHOR
 
-Copyright (C) 2017 Ole Tange,
+Copyright (C) 2017-2020 Ole Tange,
 http://ole.tange.dk and Free Software Foundation, Inc.
 
 
@@ -67,7 +87,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 =head1 DEPENDENCIES
 
-B<rand> uses B<openssl>.
+B<rand> uses B<openssl>, B<perl>, and B<parallel>.
 
 
 =head1 SEE ALSO
@@ -77,42 +97,58 @@ B<openssl>
 
 =cut
 
-# Generate random 8-bit data by AES encrypting /dev/zero with a random
-# key
-randfunc() {
+randdata() {
+    # Generate random 8-bit data by AES encrypting /dev/zero with a
+    # random key    
     key=$(openssl rand -hex 16)
     iv=$(openssl rand -hex 16)
     < /dev/zero openssl enc -aes-128-ctr -K $key -iv $iv 2>/dev/null
 }
-export -f randfunc
+export -f randdata
 
 ints() {
+    # Convert random data on stdin to numbers $from..$to in $fmt
     from=$1
     to=$2
+    fmt="$3"
     # Allow up to 2^64
     perl -e '$diff='$to-$from'+1;
         $factor = 2**64/$diff;
         while(sysread(STDIN,$buf,65536)) {
-            print map { (int($_ / $factor) + '$from'),"\n" } unpack("Q*",$buf);
+            print map { sprintf("'"$fmt"'", int($_ / $factor) + '$from'); } unpack("Q*",$buf);
         }'
 }
 export -f ints
 
 randints() {
-    randfunc | ints "$@"
+    randdata | ints "$@"
 }
 export -f randints
 
+# Default format of ints
+fmt='%s\n'
+
+while true; do
+  case "$1" in
+    -f | --fmt ) fmt="$2"; shift 2 ;;
+    -D | --debug ) debug=true; shift ;;
+    -h | --help ) help=1; shift 2 ;;
+    -- ) shift; break ;;
+    * ) break ;;
+  esac
+done
+qfmt="$(parallel --shellquote --shellquote ::: "$fmt")"
+
 if [ "$1" == "" ] ; then
     # Boost performance by running 1 per CPU core
-    eval parallel -u randfunc ::: {1..$(parallel --number-of-cores)}
+    eval parallel -u randdata ::: {1..$(parallel --number-of-threads)}
 else
     # $1 set => numerical
     if [ "$2" == "" ] ; then
 	# 0 .. $1
-	eval parallel --lb randints 0 $1 ::: {1..$(parallel --number-of-cores)}
+	eval parallel -N0 --lb randints 0 $1 "$qfmt" ::: {1..$(parallel --number-of-threads)}
     else
 	# $1 .. $2
-	eval parallel --lb randints $1 $2 ::: {1..$(parallel --number-of-cores)}
+	eval parallel -N0 --lb randints $1 $2 "$qfmt" ::: {1..$(parallel --number-of-threads)}
     fi
 fi