shithub: libmujs

Download patch

ref: 3f6b06a358af099e495e90004d9ecc829b7f367b
parent: 34cb61711fe29934dfa82ab55ea59ed85ae62642
author: Tor Andersson <tor.andersson@artifex.com>
date: Fri Jun 8 09:51:10 EDT 2018

Avoid type punning with unions.

Use memcpy, which is guaranteed to be safe under all compiler flags.

--- a/jsdtoa.c
+++ b/jsdtoa.c
@@ -407,9 +407,9 @@
 
 static uint64_t double_to_uint64(double d)
 {
-	union { double d; uint64_t n; } tmp;
-	tmp.d = d;
-	return tmp.n;
+	uint64_t n;
+	memcpy(&n, &d, 8);
+	return n;
 }
 
 #define DP_SIGNIFICAND_SIZE 52
--- a/jsi.h
+++ b/jsi.h
@@ -43,7 +43,7 @@
 #define isnan(x) _isnan(x)
 #define isinf(x) (!_finite(x))
 #define isfinite(x) _finite(x)
-static __inline int signbit(double x) {union{double d;__int64 i;}u;u.d=x;return u.i>>63;}
+static __inline int signbit(double x) { __int64 i; memcpy(&i, &x, 8); return i>>63; }
 #define INFINITY (DBL_MAX+DBL_MAX)
 #define NAN (INFINITY-INFINITY)
 #endif