fix for is_space for wchar_t and larger char types

Author: dalle

include/fast_float/float_common.h

@@ -699,7 +699,9 @@ template <typename T> constexpr bool space_lut<T>::value[];
 
 #endif
 
-inline constexpr bool is_space(uint8_t c) { return space_lut<>::value[c]; }
+template <typename UC> constexpr bool is_space(UC c) {
+  return c < 256 && space_lut<>::value[uint8_t(c)];
+}
 
 template <typename UC> static constexpr uint64_t int_cmp_zeros() {
   static_assert((sizeof(UC) == 1) || (sizeof(UC) == 2) || (sizeof(UC) == 4),

include/fast_float/parse_number.h

@@ -294,7 +294,7 @@ from_chars_float_advanced(UC const *first, UC const *last, T &value,
 
   from_chars_result_t<UC> answer;
   if (uint64_t(fmt & chars_format::skip_white_space)) {
-    while ((first != last) && fast_float::is_space(uint8_t(*first))) {
+    while ((first != last) && fast_float::is_space(*first)) {
       first++;
     }
   }
@@ -346,7 +346,7 @@ from_chars_int_advanced(UC const *first, UC const *last, T &value,
 
   from_chars_result_t<UC> answer;
   if (uint64_t(fmt & chars_format::skip_white_space)) {
-    while ((first != last) && fast_float::is_space(uint8_t(*first))) {
+    while ((first != last) && fast_float::is_space(*first)) {
       first++;
     }
   }

tests/rcppfastfloat_test.cpp

@@ -75,7 +75,7 @@ bool eddelbuettel() {
       // check that there is no content left
       for (const char *leftover = answer.ptr;
            leftover != input.data() + input.size(); leftover++) {
-        if (!fast_float::is_space(uint8_t(*leftover))) {
+        if (!fast_float::is_space(*leftover)) {
           non_space_trailing_content = true;
           break;
         }