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median.awk revision 1.4 
      1 #!/bin/awk -f
      2 #	$NetBSD: median.awk,v 1.4 1995/03/27 02:24:16 glass Exp $
      3 #
      4 # Copyright (c) 1990, 1993
      5 #	The Regents of the University of California.  All rights reserved.
      6 #
      7 # This code is derived from software contributed to Berkeley by
      8 # Van Jacobson.
      9 #
     10 # Redistribution and use in source and binary forms, with or without
     11 # modification, are permitted provided that the following conditions
     12 # are met:
     13 # 1. Redistributions of source code must retain the above copyright
     14 #    notice, this list of conditions and the following disclaimer.
     15 # 2. Redistributions in binary form must reproduce the above copyright
     16 #    notice, this list of conditions and the following disclaimer in the
     17 #    documentation and/or other materials provided with the distribution.
     18 # 3. All advertising materials mentioning features or use of this software
     19 #    must display the following acknowledgement:
     20 #	This product includes software developed by the University of
     21 #	California, Berkeley and its contributors.
     22 # 4. Neither the name of the University nor the names of its contributors
     23 #    may be used to endorse or promote products derived from this software
     24 #    without specific prior written permission.
     25 #
     26 # THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29 # ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36 # SUCH DAMAGE.
     37 #
     38 #	@(#)median.awk	8.1 (Berkeley) 6/6/93
     39 #
     40 /^ *[0-9]/	{
     41 	# print out the median time to each hop along a route.
     42 	tottime = 0; n = 0;
     43 	for (f = 5; f <= NF; ++f) {
     44 		if ($f == "ms") {
     45 			++n
     46 			time[n] = $(f - 1)
     47 		}
     48 	}
     49 	if (n > 0) {
     50 		# insertion sort the times to find the median
     51 		for (i = 2; i <= n; ++i) {
     52 			v = time[i]; j = i - 1;
     53 			while (time[j] > v) {
     54 				time[j+1] = time[j];
     55 				j = j - 1;
     56 				if (j < 0)
     57 					break;
     58 			}
     59 			time[j+1] = v;
     60 		}
     61 		if (n > 1 && (n % 2) == 0)
     62 			median = (time[n/2] + time[(n/2) + 1]) / 2
     63 		else
     64 			median = time[(n+1)/2]
     65 
     66 		print $1, median
     67 	}
     68 }
     69