/src/FreeImage/Source/OpenEXR/IlmImf/b44ExpLogTable.cpp

  1///////////////////////////////////////////////////////////////////////////
  2//
  3// Copyright (c) 2006, Industrial Light & Magic, a division of Lucas
  4// Digital Ltd. LLC
  5// 
  6// All rights reserved.
  7// 
  8// Redistribution and use in source and binary forms, with or without
  9// modification, are permitted provided that the following conditions are
 10// met:
 11// *       Redistributions of source code must retain the above copyright
 12// notice, this list of conditions and the following disclaimer.
 13// *       Redistributions in binary form must reproduce the above
 14// copyright notice, this list of conditions and the following disclaimer
 15// in the documentation and/or other materials provided with the
 16// distribution.
 17// *       Neither the name of Industrial Light & Magic nor the names of
 18// its contributors may be used to endorse or promote products derived
 19// from this software without specific prior written permission. 
 20// 
 21// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 22// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 23// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 24// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 25// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 26// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 27// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 28// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 29// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 30// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 31// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 32//
 33///////////////////////////////////////////////////////////////////////////
 34
 35//---------------------------------------------------------------------------
 36//
 37//	b44ExpLogTable
 38//
 39//	A program to generate lookup tables for
 40//
 41//		y = exp (x / 8)
 42//
 43//	and
 44//		x = 8 * log (x);
 45//
 46//	where x and y are 16-bit floating-point numbers
 47//
 48//	The tables are used by class B44Compressor.
 49//
 50//---------------------------------------------------------------------------
 51
 52#include <half.h>
 53#include <math.h>
 54#include <iostream>
 55#include <iomanip>
 56
 57using namespace std;
 58
 59//---------------------------------------------
 60// Main - prints the half-to-float lookup table
 61//---------------------------------------------
 62
 63int
 64main ()
 65{
 66#ifndef HAVE_IOS_BASE
 67    cout.setf (ios::hex, ios::basefield);
 68#else
 69    cout.setf (ios_base::hex, ios_base::basefield);
 70#endif
 71
 72    cout << "//\n"
 73	    "// This is an automatically generated file.\n"
 74	    "// Do not edit.\n"
 75	    "//\n\n";
 76
 77    const int iMax = (1 << 16);
 78
 79    cout << "const unsigned short expTable[] =\n"
 80	    "{\n"
 81	    "    ";
 82
 83    for (int i = 0; i < iMax; i++)
 84    {
 85	half h;
 86	h.setBits (i);
 87
 88	if (!h.isFinite())
 89	    h = 0;
 90	else if (h >= 8 * log (HALF_MAX))
 91	    h = HALF_MAX;
 92	else
 93	    h = exp (h / 8);
 94
 95	cout << "0x" << setfill ('0') << setw (4) << h.bits() << ", ";
 96
 97	if (i % 8 == 7)
 98	{
 99	    cout << "\n";
100
101	    if (i < iMax - 1)
102		cout << "    ";
103	}
104    }
105
106    cout << "};\n\n";
107
108    cout << "const unsigned short logTable[] =\n"
109	    "{\n"
110	    "    ";
111
112    for (int i = 0; i < iMax; i++)
113    {
114	half h;
115	h.setBits (i);
116
117	if (!h.isFinite() || h < 0)
118	    h = 0;
119	else
120	    h = 8 * log (h);
121
122	cout << "0x" << setfill ('0') << setw (4) << h.bits() << ", ";
123
124	if (i % 8 == 7)
125	{
126	    cout << "\n";
127
128	    if (i < iMax - 1)
129		cout << "    ";
130	}
131    }
132
133    cout << "};\n";
134
135    return 0;
136}