fix(hexfloat): extraneous '.' when no exponent, ParseHex should handle specials

Author: rvagg

src/literal.cc

@@ -253,6 +253,17 @@ template <typename T>
 Result FloatParser<T>::ParseHex(const char* s,
                                 const char* end,
                                 Uint* out_bits) {
+  if ((end - s >= 3 && strncmp(s, "inf", 3) == 0) ||
+      (end - s >= 4 && strncmp(s, "-inf", 4) == 0)) {
+    ParseInfinity(s, end, out_bits);
+    return Result::Ok;
+  }
+  if ((end - s >= 3 && strncmp(s, "nan", 3) == 0) ||
+      (end - s >= 4 && strncmp(s, "nan:", 4) == 0)) {
+    ParseNan(s, end, out_bits);
+    return Result::Ok;
+  }
+
   bool is_neg = false;
   if (*s == '-') {
     is_neg = true;
@@ -515,11 +526,13 @@ void FloatWriter<T>::WriteHex(char* out, size_t size, Uint bits) {
         exp -= leading_zeroes;
       }
 
-      *p++ = '.';
-      while (sig) {
-        int nybble = (sig >> kTopNybbleShift) & 0xf;
-        *p++ = s_hex_digits[nybble];
-        sig <<= 4;
+      if (sig) {
+        *p++ = '.';
+        while (sig) {
+          int nybble = (sig >> kTopNybbleShift) & 0xf;
+          *p++ = s_hex_digits[nybble];
+          sig <<= 4;
+        }
       }
     }
     *p++ = 'p';