#ifndef _BLURB_
#define _BLURB_
/*

            Coda: an Experimental Distributed File System
                             Release 3.1

          Copyright (c) 1987-1995 Carnegie Mellon University
                         All Rights Reserved

Permission  to  use, copy, modify and distribute this software and its
documentation is hereby granted,  provided  that  both  the  copyright
notice  and  this  permission  notice  appear  in  all  copies  of the
software, derivative works or  modified  versions,  and  any  portions
thereof, and that both notices appear in supporting documentation, and
that credit is given to Carnegie Mellon University  in  all  documents
and publicity pertaining to direct or indirect use of this code or its
derivatives.

CODA IS AN EXPERIMENTAL SOFTWARE SYSTEM AND IS  KNOWN  TO  HAVE  BUGS,
SOME  OF  WHICH MAY HAVE SERIOUS CONSEQUENCES.  CARNEGIE MELLON ALLOWS
FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION.   CARNEGIE  MELLON
DISCLAIMS  ANY  LIABILITY  OF  ANY  KIND  FOR  ANY  DAMAGES WHATSOEVER
RESULTING DIRECTLY OR INDIRECTLY FROM THE USE OF THIS SOFTWARE  OR  OF
ANY DERIVATIVE WORK.

Carnegie  Mellon  encourages  users  of  this  software  to return any
improvements or extensions that  they  make,  and  to  grant  Carnegie
Mellon the rights to redistribute these changes without encumbrance.
*/

static char *rcsid = "$Header: histo.c,v 3.2.1.1 95/10/11 10:22:55 raiff Exp $";
#endif /*_BLURB_*/








#include <stdio.h>
#include <libc.h>
#include <sysent.h>
#include <math.h>
#include <assert.h>
#include "histo.h"

/* Math.h doesn't define HUGE appropriately for suns... */
#ifdef sun
#define HUGE 1.701411733192644270e38
#endif

  InitHisto(hg, lolimit, hilimit, bucketcount, ht)
    struct hgram *hg;
    double lolimit;
    double hilimit;
    int bucketcount;
    enum htype ht;
    /* Initializes histogram hg. Returns 0 on success, -1 on failure.
       bucketcount is ignored if ht is LOG2 or LOG10  */
    {
    int i, t1, t2;

    if (lolimit >= hilimit) return(-1);
    if (ht != LINEAR && lolimit <= 0) return(-1);

    hg->type = ht;
    switch (ht)
	{
	case LINEAR:
	    hg->maxb = bucketcount;
	    hg->uflow.hival = lolimit;
	    hg->oflow.loval = hilimit; 
	    break;
	
	case LOG2:
	    t1 = (int) floor(log(lolimit)/LN2);
	    t2 = (int) ceil(log(hilimit)/LN2);
	    hg->maxb = t2 - t1;
	    hg->uflow.hival = RAISE2(t1);
	    hg->oflow.loval = RAISE2(t2);
	    break;
	
	case LOG10:
	    t1 = (int) floor(log10(lolimit));
	    t2 = (int) ceil(log10(hilimit));
	    hg->maxb = 9*(t2 - t1);
	    hg->uflow.hival = RAISE10(t1);
	    hg->oflow.loval = RAISE10(t2);
	    break;
	
	default:
	    return(-1);
	}
	
    
    hg->oflow.hival = HUGE;
    hg->uflow.loval = -HUGE;

    hg->buckets = (struct histo *) calloc(hg->maxb, sizeof(struct histo));
    if (!hg->buckets) return(-1); /* calloc() failed */
    
    /* NB: If you modify the code below make sure the change
       still avoids "gaps" in the histo buckets. Can be tricky.  */

    hg->buckets[0].loval = hg->uflow.hival;
    hg->buckets[hg->maxb-1].hival = hg->oflow.loval;
    
    if (ht == LINEAR)
	{
	double step;

	step = (hilimit - lolimit)/bucketcount;
	for (i = 0; i < hg->maxb-1; i++)
	    {
	    hg->buckets[i].hival = hg->buckets[i].loval + step;
	    hg->buckets[i+1].loval = hg->buckets[i].hival;
	    }
	}
    else
	{/* LOG2 or LOG10 */
	double adder;
	int logbase;
	
	logbase = (ht == LOG2 ? 2 : 10);
	adder = hg->buckets[0].loval;
	
	for (i = 0; i < hg->maxb-1; i++)
	    {
	    hg->buckets[i].hival = hg->buckets[i].loval + adder;
	    hg->buckets[i+1].loval = hg->buckets[i].hival;
	    if ((i+1) % (logbase - 1) == 0) adder *= logbase;
	    }
	}

    ClearHisto(hg);	
    
    return(0);
    }



void ClearHisto(hg)
     struct hgram *hg;
    /* Clears histogram hg. */
    {
    int i;

    hg->count = 0;
    hg->sum = 0.0;
    hg->sum2 = 0.0;
    
    hg->oflow.count = 0;
    hg->uflow.count = 0;
    
    for (i = 0; i < hg->maxb; i++)
	hg->buckets[i].count = 0;
    }
    

void UpdateHisto(hg, newval)
     register struct hgram *hg;
     double newval;
    /* hg -- histogram to be updated
       newval -- value to be entered */
    {
    MUpdateHisto(hg, newval, 1);
    }

void MUpdateHisto(hg,newval,number)
     register struct hgram *hg;
     double newval;
     int number;
    /* hg -- histogram to be updated
       newval -- value to be entered 
       number -- number of newvals to be entered */
    {
    register int i;
    
    if (newval < hg->uflow.hival)
	{
	hg->uflow.count += number;
	return;
	}
	
    if (newval >= hg->oflow.loval)
	{
	hg->oflow.count += number;
	return;
	}

    for (i = 0; i < hg->maxb; i++)
	{/* I know I could use binary search here */
	if (newval >= hg->buckets[i].hival) continue;

	/* Foundit! */
	hg->buckets[i].count += number;
	hg->count += number;
	hg->sum += newval*(double)number;
	hg->sum2 += newval*newval*(double)number;
	assert(hg->sum >= 0);
	assert(hg->sum2 >= 0);
	return;
	}

    /* Should never get here */
    assert(0);
    }


static double CIFactor(dFreedom)
     int dFreedom;
    /* dFreedom:  no of degrees of freedom; == (NoOfSamples - 1) */
    {
    /* Approximate; errs conservatively; see Law & Kelton, pg 386 */
    static double lowCI[20] = {-1.0, 3.078, 1.886, 1.638, 1.533, 1.476,
			1.440,1.415, 1.397, 1.383, 1.372,
			1.363, 1.356, 1.35, 1.345, 1.341, 1.337, 1.333, 1.33, 1.328};

    if (dFreedom >= 100) return(1.29);
    if (dFreedom >= 50)  return(1.3);
    if (dFreedom >= 30) return(1.31);
    if (dFreedom >= 20) return (1.325);
    return(lowCI[dFreedom]);
    }

PrintHisto(outfile, hg)
     FILE *outfile;
     register struct hgram *hg;
    {
    double mean, stddev, c90;
    double temp;
    register int i;    
    
    /* Compute mean, std deviation and confidence interval */
    if (hg->count < 1) mean = 0.0;
    else  mean = hg->sum/(double)hg->count;

    if (hg->count < 2) stddev = c90 = 0.0;
    else
	{
	fprintf(outfile,"Count = %d, Sum = %g, Sum2 = %g\n", hg->count, hg->sum, hg->sum2); fflush(outfile);
	temp =	((double)hg->count*hg->sum2 - hg->sum*hg->sum) / ((double)hg->count*(double)(hg->count-1));
	assert(temp >= 0);
	stddev = sqrt(temp);
	c90 = stddev*CIFactor(hg->count - 1);
	}
	
    if (fprintf(outfile, "Good samples:     count = %d    mean = %g   stddev = %g   90%%CI = %g\n\n",
    		hg->count, mean, stddev, c90) == -1) return -1;
    if (fprintf(outfile, "Bad samples:      underflow = %d    overflow = %d\n\n",
    		hg->uflow.count, hg->oflow.count) == -1) return -1;
    
    if (hg->uflow.count)
	if (fprintf (outfile, "        %d samples in the range -INFINITY to %g\n",
		hg->uflow.count, hg->uflow.hival) == -1) return -1;

    for (i = 0; i < hg->maxb; i++)
	{
	if (hg->buckets[i].count)
	    if (fprintf (outfile, "        %d samples in the range %g to %g\n",
		hg->buckets[i].count, hg->buckets[i].loval, hg->buckets[i].hival) == -1) return -1;
	}

    if (hg->oflow.count)
	if (fprintf (outfile, "        %d samples in the range %g to INFINITY\n",
	    	hg->oflow.count, hg->oflow.loval) == -1) return -1;
    }



int PlotHisto(outfile, hg, graphtitle, xtitle, ytitle, psfileprefix)
     FILE *outfile;
     struct hgram *hg;
     char *graphtitle;
     char *xtitle;
     char *ytitle;
     char *psfileprefix;
     
    {
    register int i;
    int maxcount, totalcount;
    static int plotid = 1;

    if (fprintf(outfile, "New Page\n") == -1) return -1;
    if (fprintf(outfile, "New Graph\n") == -1) return -1;
    if (fprintf(outfile, "Graph Title %s\n", graphtitle) == -1)
      return -1;
    if (fprintf(outfile, "Curve Type Solid\n") == -1) return -1;
    if (fprintf(outfile, "Curve Symbol None\n") == -1) return -1;
    if (fprintf(outfile, "Curve Interpolation XHistogram\n") == -1)
      return -1;
    if (fprintf(outfile, "Curve Confidence no\n") == -1) return -1;

    /* Obtain total count to estimate percentages */
    totalcount = maxcount = 0;
    for (i = 0; i < hg->maxb; i++)
	{
	totalcount += hg->buckets[i].count;
	if (hg->buckets[i].count > maxcount) maxcount = hg->buckets[i].count;
	}

    /* Print out the points */
    if (fprintf(outfile, "New Points\n") == -1) return -1;
    for (i = 0; i < hg->maxb; i++)
	{
	if (fprintf(outfile, "%g %g\n", hg->buckets[i].loval, (hg->buckets[i].count*100.0)/(totalcount*1.0)) == -1)
            return -1;
	}
    if (fprintf(outfile, "\n") == -1) return -1;
	
    if (fprintf(outfile, "X Minimum %g\n", hg->uflow.hival) == -1)
      return -1;
    if (fprintf(outfile, "X Maximum %g\n", hg->oflow.loval) == -1) 
      return -1;
    switch(hg->type)
	{
	case LINEAR:
	    if (fprintf(outfile, "X Scale Linear\n") == -1)
              return -1;
	    break;
	
	case LOG2:
	    if (fprintf(outfile, "X LogBase 2\n") == -1) return -1;
	    if (fprintf(outfile, "X Scale Log\n") == -1) return -1;
	    break;	
	
	case LOG10:
	    if (fprintf(outfile, "X LogBase 10\n") == -1) 
              return -1;
	    if (fprintf(outfile, "X Scale Log\n") == -1) return -1;
	    break;	

	}
    if (fprintf(outfile, "X Label %s\n", xtitle) == -1) return -1;

    if (fprintf(outfile, "Y Minimum %d\n", 0) == -1) return -1;
    if (fprintf(outfile, "Y Maximum %g\n", ceil((maxcount*100.0)/(totalcount*1.0)) ) == -1) return -1;
    if (fprintf(outfile, "Y Scale Linear\n") == -1) return -1;
    if (fprintf(outfile, "Y Label %s\n", ytitle) == -1) return -1;


    if (fprintf(outfile, "Plot postscript %s%d.PS nodocument noprint\n\n", psfileprefix, plotid++) == -1) 
              return -1;
    }
