diff options
Diffstat (limited to 'base/rand_util.cc')
-rw-r--r-- | base/rand_util.cc | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/base/rand_util.cc b/base/rand_util.cc index a71bb0c..b823fa0 100644 --- a/base/rand_util.cc +++ b/base/rand_util.cc @@ -24,6 +24,10 @@ int RandInt(int min, int max) { } double RandDouble() { + return BitsToOpenEndedUnitInterval(base::RandUint64()); +} + +double BitsToOpenEndedUnitInterval(uint64 bits) { // We try to get maximum precision by masking out as many bits as will fit // in the target type's mantissa, and raising it to an appropriate power to // produce output in the range [0, 1). For IEEE 754 doubles, the mantissa @@ -31,7 +35,7 @@ double RandDouble() { COMPILE_ASSERT(std::numeric_limits<double>::radix == 2, otherwise_use_scalbn); static const int kBits = std::numeric_limits<double>::digits; - uint64 random_bits = base::RandUint64() & ((GG_UINT64_C(1) << kBits) - 1); + uint64 random_bits = bits & ((GG_UINT64_C(1) << kBits) - 1); double result = ldexp(static_cast<double>(random_bits), -1 * kBits); DCHECK_GE(result, 0.0); DCHECK_LT(result, 1.0); |