From ce562d9c65fee59e71dadff9a29ba86a7fba3b68 Mon Sep 17 00:00:00 2001
From: Maya Warrier <maya.warrierm@gmail.com>
Date: Thu, 14 Sep 2023 20:51:26 -0400
Subject: [PATCH] Disallow inf/nan in json mode

---
 include/fast_float/ascii_number.h | 8 ++++----
 include/fast_float/float_common.h | 5 ++++-
 include/fast_float/parse_number.h | 8 +++++++-
 tests/json_fmt.cpp                | 2 +-
 4 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/include/fast_float/ascii_number.h b/include/fast_float/ascii_number.h
index 21fbac4..9653889 100644
--- a/include/fast_float/ascii_number.h
+++ b/include/fast_float/ascii_number.h
@@ -280,7 +280,7 @@ parsed_number_string_t<UC> parse_number_string(UC const *p, UC const * pend, par
   answer.too_many_digits = false;
   answer.negative = (*p == UC('-'));
 #ifdef FASTFLOAT_ALLOWS_LEADING_PLUS // disabled by default
-  if ((*p == UC('-')) || (fmt != chars_format::json && *p == UC('+'))) {
+  if ((*p == UC('-')) || (!(fmt & FASTFLOAT_JSONFMT) && *p == UC('+'))) {
 #else
   if (*p == UC('-')) { // C++17 20.19.3.(7.1) explicitly forbids '+' sign here
 #endif
@@ -288,7 +288,7 @@ parsed_number_string_t<UC> parse_number_string(UC const *p, UC const * pend, par
     if (p == pend) {
       return answer;
     }
-    if (fmt == chars_format::json) {
+    if (fmt & FASTFLOAT_JSONFMT) {
       if (!is_integer(*p)) { // a sign must be followed by an integer
         return answer;
       }    
@@ -312,7 +312,7 @@ parsed_number_string_t<UC> parse_number_string(UC const *p, UC const * pend, par
   UC const * const end_of_integer_part = p;
   int64_t digit_count = int64_t(end_of_integer_part - start_digits);
   answer.integer = span<const UC>(start_digits, size_t(digit_count));
-  if (fmt == chars_format::json) {
+  if (fmt & FASTFLOAT_JSONFMT) {
     // at least 1 digit in integer part, without leading zeros
     if (digit_count == 0 || (start_digits[0] == UC('0') && digit_count > 1)) {
       return answer;
@@ -337,7 +337,7 @@ parsed_number_string_t<UC> parse_number_string(UC const *p, UC const * pend, par
     answer.fraction = span<const UC>(before, size_t(p - before));
     digit_count -= exponent;
   }
-  if (fmt == chars_format::json) {
+  if (fmt & FASTFLOAT_JSONFMT) {
     // at least 1 digit in fractional part
     if (has_decimal_point && exponent == 0) {
       return answer;
diff --git a/include/fast_float/float_common.h b/include/fast_float/float_common.h
index 7050073..c101673 100644
--- a/include/fast_float/float_common.h
+++ b/include/fast_float/float_common.h
@@ -12,11 +12,14 @@
 
 namespace fast_float {
 
+#define FASTFLOAT_JSONFMT (1 << 5)
+
 enum chars_format {
   scientific = 1 << 0,
   fixed = 1 << 2,
   hex = 1 << 3,
-  json = 1 << 4 | fixed | scientific,
+  no_infnan = 1 << 4,
+  json = FASTFLOAT_JSONFMT | fixed | scientific | no_infnan,
   general = fixed | scientific
 };
 
diff --git a/include/fast_float/parse_number.h b/include/fast_float/parse_number.h
index e077b9d..a011a8c 100644
--- a/include/fast_float/parse_number.h
+++ b/include/fast_float/parse_number.h
@@ -164,7 +164,13 @@ from_chars_result_t<UC> from_chars_advanced(UC const * first, UC const * last,
   }
   parsed_number_string_t<UC> pns = parse_number_string<UC>(first, last, options);
   if (!pns.valid) {
-    return detail::parse_infnan(first, last, value);
+    if (options.format & chars_format::no_infnan) {
+      answer.ec = std::errc::invalid_argument;
+      answer.ptr = first;
+      return answer;
+    } else {
+      return detail::parse_infnan(first, last, value);
+    }
   }
 
   answer.ec = std::errc(); // be optimistic
diff --git a/tests/json_fmt.cpp b/tests/json_fmt.cpp
index b1c3977..1fdd636 100644
--- a/tests/json_fmt.cpp
+++ b/tests/json_fmt.cpp
@@ -12,7 +12,7 @@ int main()
 {
   const std::vector<double> expected{ -0.2, 0.02, 0.002, 1., 0. };
   const std::vector<std::string> accept{ "-0.2", "0.02", "0.002", "1e+0000", "0e-2" };
-  const std::vector<std::string> reject{ "-.2", "00.02", "0.e+1", "00.e+1", ".25", "+0.25"};
+  const std::vector<std::string> reject{ "-.2", "00.02", "0.e+1", "00.e+1", ".25", "+0.25", "inf", "nan(snan)"};
   const auto fmt = fast_float::chars_format::json;
 
   for (std::size_t i = 0; i < accept.size(); ++i)