Support rccpfastfloat.

include/fast_float/ascii_number.h

@@ -93,7 +93,11 @@ parsed_number_string parse_number_string(const char *p, const char *pend, parse_
   answer.valid = false;
   answer.too_many_digits = false;
   answer.negative = (*p == '-');
+#if FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
+  if ((*p == '-') || (*p == '+')) {
+#else
   if (*p == '-') { // C++17 20.19.3.(7.1) explicitly forbids '+' sign here
+#endif
     ++p;
     if (p == pend) {
       return answer;

include/fast_float/float_common.h

@@ -81,12 +81,11 @@
 #endif
 
 #ifndef FASTFLOAT_ASSERT
-#define FASTFLOAT_ASSERT(x)  { if (!(x)) abort(); }
+#define FASTFLOAT_ASSERT(x)  { ((void)(x)); }
 #endif
 
 #ifndef FASTFLOAT_DEBUG_ASSERT
-#include <cassert>
+#define FASTFLOAT_DEBUG_ASSERT(x) { ((void)(x)); }
-#define FASTFLOAT_DEBUG_ASSERT(x) assert(x)
 #endif
 
 // rust style `try!()` macro, or `?` operator
@@ -453,6 +452,23 @@ fastfloat_really_inline void to_float(bool negative, adjusted_mantissa am, T &va
 #endif
 }
 
+#if FASTFLOAT_SKIP_WHITE_SPACE // disabled by default
+inline bool is_space(uint8_t c) {
+   static const bool table[] = {
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+   return table[c];
+ }
+#endif
 } // namespace fast_float
 
 #endif

include/fast_float/parse_number.h

@@ -136,6 +136,11 @@ from_chars_result from_chars_advanced(const char *first, const char *last,
 
 
   from_chars_result answer;
+#if FASTFLOAT_SKIP_WHITE_SPACE  // disabled by default
+  while ((first != last) && fast_float::is_space(uint8_t(*first))) {
+    first++;
+  }
+#endif
   if (first == last) {
     answer.ec = std::errc::invalid_argument;
     answer.ptr = first;

tests/CMakeLists.txt

@@ -56,7 +56,7 @@ function(fast_float_add_cpp_test TEST_NAME)
     endif()
 endfunction(fast_float_add_cpp_test)
 
-
+fast_float_add_cpp_test(rcppfastfloat_test)
 fast_float_add_cpp_test(example_test)
 fast_float_add_cpp_test(example_comma_test)
 fast_float_add_cpp_test(basictest)

tests/rcppfastfloat_test.cpp

@@ -0,0 +1,123 @@
+/**
+ * See https://github.com/eddelbuettel/rcppfastfloat/issues/4
+ */
+
+#define FASTFLOAT_ALLOWS_LEADING_PLUS 1
+#define FASTFLOAT_SKIP_WHITE_SPACE 1 // important !
+#include "fast_float/fast_float.h"
+#include <iostream>
+#include <string>
+#include <vector>
+
+bool eddelbuettel() {
+  std::vector<std::string> inputs = {"infinity",
+                                     " \r\n\t\f\v3.16227766016838 \r\n\t\f\v",
+                                     " \r\n\t\f\v3 \r\n\t\f\v",
+                                     "  1970-01-01",
+                                     "-NaN",
+                                     "-inf",
+                                     " \r\n\t\f\v2.82842712474619 \r\n\t\f\v",
+                                     "nan",
+                                     " \r\n\t\f\v2.44948974278318 \r\n\t\f\v",
+                                     "Inf",
+                                     " \r\n\t\f\v2 \r\n\t\f\v",
+                                     "-infinity",
+                                     " \r\n\t\f\v0 \r\n\t\f\v",
+                                     " \r\n\t\f\v1.73205080756888 \r\n\t\f\v",
+                                     " \r\n\t\f\v1 \r\n\t\f\v",
+                                     " \r\n\t\f\v1.4142135623731 \r\n\t\f\v",
+                                     " \r\n\t\f\v2.23606797749979 \r\n\t\f\v",
+                                     "1970-01-02  ",
+                                     " \r\n\t\f\v2.64575131106459 \r\n\t\f\v",
+                                     "inf",
+                                     "-nan",
+                                     "NaN",
+                                     "",
+                                     "-Inf",
+                                     "+2.2"};
+  std::vector<std::pair<bool, double>> expected_results = {
+      {true, std::numeric_limits<double>::infinity()},
+      {true, 3.16227766016838},
+      {true, 3},
+      {false, -1},
+      {true, std::numeric_limits<double>::quiet_NaN()},
+      {true, -std::numeric_limits<double>::infinity()},
+      {true, 2.82842712474619},
+      {true, std::numeric_limits<double>::quiet_NaN()},
+      {true, 2.44948974278318},
+      {true, std::numeric_limits<double>::infinity()},
+      {true, 2},
+      {true, -std::numeric_limits<double>::infinity()},
+      {true, 0},
+      {true, 1.73205080756888},
+      {true, 1},
+      {true, 1.4142135623731},
+      {true, 2.23606797749979},
+      {false, -1},
+      {true, 2.64575131106459},
+      {true, std::numeric_limits<double>::infinity()},
+      {true, std::numeric_limits<double>::quiet_NaN()},
+      {true, std::numeric_limits<double>::quiet_NaN()},
+      {false, -1},
+      {true, -std::numeric_limits<double>::infinity()},
+      {true, 2.2}};
+  for (size_t i = 0; i < inputs.size(); i++) {
+    std::string &input = inputs[i];
+    std::pair<bool, double> expected = expected_results[i];
+    double result;
+    // answer contains a error code and a pointer to the end of the
+    // parsed region (on success).
+    auto answer = fast_float::from_chars(input.data(),
+                                         input.data() + input.size(), result);
+    if (answer.ec != std::errc()) {
+      std::cout << "could not parse" << std::endl;
+      if (expected.first) {
+        return false;
+      }
+      continue;
+    }
+    bool non_space_trailing_content = false;
+    if (answer.ptr != input.data() + input.size()) {
+      // 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))) {
+          non_space_trailing_content = true;
+          break;
+        }
+      }
+    }
+    if (non_space_trailing_content) {
+      std::cout << "found trailing content " << std::endl;
+    }
+
+    if (non_space_trailing_content) {
+      if (!expected.first) {
+        continue;
+      } else {
+        return false;
+      }
+    }
+    std::cout << "parsed " << result << std::endl;
+    if (!expected.first) {
+      return false;
+    }
+    if (result != expected.second) {
+      if (std::isnan(result) && std::isnan(expected.second)) {
+        continue;
+      }
+      std::cout << "results do not match. Expected "<<  expected.second << std::endl;
+      return false;
+    }
+  }
+  return true;
+}
+
+int main() {
+  if (!eddelbuettel()) {
+    printf("Bug.\n");
+    return EXIT_FAILURE;
+  }
+  printf("All ok.\n");
+  return EXIT_SUCCESS;
+}