raw_ostream: [PR6745] Tweak formatting (double)%e for Windows hosts.
On MSVCRT and compatible, output of %e is incompatible to Posix by default. Number of exponent digits should be at least 2. "%+03d"
FIXME: Implement our formatter in future!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127872 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/raw_ostream.cpp b/lib/Support/raw_ostream.cpp
index a2ca101..5a71fa3 100644
--- a/lib/Support/raw_ostream.cpp
+++ b/lib/Support/raw_ostream.cpp
@@ -220,6 +220,36 @@
}
raw_ostream &raw_ostream::operator<<(double N) {
+#ifdef _WIN32
+ // On MSVCRT and compatible, output of %e is incompatible to Posix
+ // by default. Number of exponent digits should be at least 2. "%+03d"
+ // FIXME: Implement our formatter to here or Support/Format.h!
+ int fpcl = _fpclass(N);
+
+ // negative zero
+ if (fpcl == _FPCLASS_NZ)
+ return *this << "-0.000000e+00";
+
+ char buf[16];
+ unsigned len;
+ len = snprintf(buf, sizeof(buf), "%e", N);
+ if (len <= sizeof(buf) - 2) {
+ if (len >= 5 && buf[len - 5] == 'e' && buf[len - 3] == '0') {
+ int cs = buf[len - 4];
+ if (cs == '+' || cs == '-') {
+ int c1 = buf[len - 2];
+ int c0 = buf[len - 1];
+ if (isdigit(c1) && isdigit(c0)) {
+ // Trim leading '0': "...e+012" -> "...e+12\0"
+ buf[len - 3] = c1;
+ buf[len - 2] = c0;
+ buf[--len] = 0;
+ }
+ }
+ }
+ return this->operator<<(buf);
+ }
+#endif
return this->operator<<(format("%e", N));
}