--- /dev/null
+/*
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <math.h>
+
+#include <uobject/uobject.h>
+#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);
+}