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SGI Developer Toolbox 6.1
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SGI Developer Toolbox 6.1 - Disc 4.iso
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fax
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sgi2fax
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lut.c
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C/C++ Source or Header
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1994-08-01
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3KB
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107 lines
/* $Header: /usr/people/sam/fax/sgi2fax/RCS/lut.c,v 1.5 1994/02/28 14:23:11 sam Rel $
/*
* Copyright (c) 1990, 1991, 1992, 1993, 1994 Sam Leffler
* Copyright (c) 1991, 1992, 1993, 1994 Silicon Graphics, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software and
* its documentation for any purpose is hereby granted without fee, provided
* that (i) the above copyright notices and this permission notice appear in
* all copies of the software and related documentation, and (ii) the names of
* Sam Leffler and Silicon Graphics may not be used in any advertising or
* publicity relating to the software without the specific, prior written
* permission of Sam Leffler and Silicon Graphics.
*
* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
*
* IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
#include "lut.h"
float frand();
lut *makelut(func,insteps,outsteps,stoclut)
float (*func)();
int insteps, outsteps, stoclut;
{
lut *l;
int i;
float low, high, inspace;
l = (lut *)malloc(sizeof(lut));
l->insteps = insteps;
l->outsteps = outsteps;
l->stoclut = stoclut;
if(stoclut) {
l->flow = (float *)malloc(insteps*sizeof(float));
l->fhigh = (float *)malloc(insteps*sizeof(float));
inspace = insteps-1.0;
for(i=0; i<insteps; i++) {
low = (i-0.5)/inspace;
high = (i+0.5)/inspace;
if(low<0.0)
low = 0.0;
if(high>1.0)
high = 1.0;
l->flow[i] = (func)(low);
l->fhigh[i] = (func)(high);
}
} else {
l->stab = (unsigned short *)malloc(insteps*sizeof(unsigned short));
inspace = insteps-1.0;
for(i=0; i<insteps; i++)
l->stab[i] = (l->outsteps-1)*(func)(i/inspace)+0.5;
}
return l;
}
applylut(l,sptr,n)
lut *l;
unsigned short *sptr;
int n;
{
float delta, val;
float *fhigh, *flow;
unsigned short *stab;
float outspace;
int ival;
if(l->stoclut) {
fhigh = l->fhigh;
flow = l->flow;
outspace = l->outsteps-1;
while(n--) {
delta = fhigh[*sptr]-flow[*sptr];
val = outspace*(flow[*sptr]+frand()*delta);
ival = val;
if((val-ival)<frand())
*sptr++ = ival;
else
*sptr++ = ival+1;
}
} else {
stab = l->stab;
while(n--) {
*sptr = stab[*sptr];
sptr++;
}
}
}
void freelut(lut* l)
{
if(l->stoclut) {
free((char*)l->flow);
free((char*)l->fhigh);
} else {
free((char*)l->stab);
}
free((char*)l);
}