/*
* upkg: tool for manipulating Unreal Tournament packages.
* Copyright © 2012, 2020 Nick Bowler
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
#include
#include
#include
#include "pack.h"
/*
* Deserialize an IEEE 754 binary32 value in "little endian" (for whatever
* that term is worth in this context). That is, when interpreted as a little
* endian 32-bit unsigned integer: bit 31 is the sign, bits 30-23 are the
* (biased) exponent, and bits 22-0 are the encoded part of the significand.
*
* The implementation is designed to be agnostic of the platform's actual
* float type, but the conversion may be lossy if "float" is not itself a
* binary32 format. NaN payloads are not preserved.
*/
float u_unpack_binary32_le(const unsigned char *buf)
{
unsigned long raw;
long significand;
int exponent;
float result;
raw = unpack_32_le(buf);
exponent = (raw & 0x7f800000) >> 23;
significand = (raw & 0x007fffff) >> 0;
switch (exponent) {
case 255:
result = significand ? NAN : INFINITY;
break;
default:
significand |= 0x00800000;
/* fall through */
case 0:
result = ldexpf(significand, exponent-126-24);
}
return copysignf(result, raw & 0x80000000 ? -1 : 1);
}