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/*
* This software is copyrighted as noted below. It may be freely copied,
* modified, and redistributed, provided that the copyright notice is
* preserved on all copies.
*
* There is no warranty or other guarantee of fitness for this software,
* it is provided solely "as is". Bug reports or fixes may be sent
* to the author, who may or may not act on them as he desires.
*
* You may not include this software in a program or other software product
* without supplying the source, or without informing the end-user that the
* source is available for no extra charge.
*
* If you modify this software, you should include a notice giving the
* name of the person performing the modification, the date of modification,
* and the reason for such modification.
*
* Modified at BRL 16-May-88 by Mike Muuss to avoid Alliant STDC problem
* with <math.h> having defines for "exp" conflicting with local vars.
*/
/*
* float_to_exp.c - Convert floating point values to exponent bytes
*
* Author: John W. Peterson
* Computer Science Dept.
* University of Utah
* Date: Thu Oct 29 1987
* Copyright (c) 1987, University of Utah
*/
#include <stdio.h>
#include <rle.h>
#include <math.h>
/*****************************************************************
* TAG( float_to_exp )
*
* Takes an array of count floating point numbers, and makes an array
* of count+1 pixels out of it.
*/
void
float_to_exp( count, floats, pixels )
int count;
float * floats;
rle_pixel * pixels;
{
register int i;
int expon, max_exp = -2000;
float * fptr = floats;
double f_exp;
/* Find largest exponent */
/* Use "Block normalization":
* ExpScan[x] is largest exponent of the three
* color components. Red/Grn/BluScan[1..3] are the
* normalized color components.
*/
for (i = 0; i < count; i++)
{
frexp( *fptr++, &expon );
max_exp = (expon > max_exp) ? expon : max_exp;
}
/* Don't over/underflow */
if (max_exp > 128) max_exp = 128;
else
if (max_exp < -127) max_exp = -127;
f_exp = ldexp( 256.0, -max_exp );
fptr = floats;
for( i = 0; i < count; i++ ) /* Extra casts for broken HP compiler */
*pixels++ = (rle_pixel) ((int)(*fptr++ * f_exp));
/* Excess 127 exponent */
*pixels = (rle_pixel) (max_exp + 127);
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.