fix: don't fail on overflow

Alvaro-Kothe · Alvaro-Kothe · commit 163c5384d372 · 2026-01-31T19:12:33.000-03:00
diff --git a/cpp/src/arrow/util/value_parsing.cc b/cpp/src/arrow/util/value_parsing.cc
@@ -35,15 +35,21 @@ bool StringToFloat(const char* s, size_t length, char decimal_point, float* out)
       ::arrow_vendored::fast_float::chars_format::general, decimal_point};
   const auto res =
       ::arrow_vendored::fast_float::from_chars_advanced(s, s + length, *out, options);
-  return res.ec == std::errc() && res.ptr == s + length;
+  const bool is_valid_number =
+      res.ec == std::errc() || res.ec == std::errc::result_out_of_range;
+  const bool consumed_entire_string = res.ptr == s + length;
+  return is_valid_number && consumed_entire_string;
 }
 
 bool StringToFloat(const char* s, size_t length, char decimal_point, double* out) {
   ::arrow_vendored::fast_float::parse_options options{
       ::arrow_vendored::fast_float::chars_format::general, decimal_point};
   const auto res =
       ::arrow_vendored::fast_float::from_chars_advanced(s, s + length, *out, options);
-  return res.ec == std::errc() && res.ptr == s + length;
+  const bool is_valid_number =
+      res.ec == std::errc() || res.ec == std::errc::result_out_of_range;
+  const bool consumed_entire_string = res.ptr == s + length;
+  return is_valid_number && consumed_entire_string;
 }
 
 // Half float
@@ -53,7 +59,10 @@ bool StringToFloat(const char* s, size_t length, char decimal_point, Float16* ou
   float temp_out;
   const auto res =
       ::arrow_vendored::fast_float::from_chars_advanced(s, s + length, temp_out, options);
-  const bool ok = res.ec == std::errc() && res.ptr == s + length;
+  const bool is_valid_number =
+      res.ec == std::errc() || res.ec == std::errc::result_out_of_range;
+  const bool consumed_entire_string = res.ptr == s + length;
+  const bool ok = is_valid_number && consumed_entire_string;
   if (ok) {
     *out = Float16::FromFloat(temp_out);
   }
diff --git a/cpp/src/arrow/util/value_parsing_test.cc b/cpp/src/arrow/util/value_parsing_test.cc
@@ -141,6 +141,9 @@ TEST(StringConversion, ToFloat) {
   AssertConversion<FloatType>("0", 0.0f);
   AssertConversion<FloatType>("-0.0", -0.0f);
   AssertConversion<FloatType>("-1e20", -1e20f);
+  AssertConversion<FloatType>("4e38", std::numeric_limits<float>::infinity());
+  AssertConversion<FloatType>("-4e38", -std::numeric_limits<float>::infinity());
+  AssertConversion<FloatType>("1e-46", 0.0f);
   AssertConversion<FloatType>("+Infinity", std::numeric_limits<float>::infinity());
   AssertConversion<FloatType>("-Infinity", -std::numeric_limits<float>::infinity());
   AssertConversion<FloatType>("Infinity", std::numeric_limits<float>::infinity());
@@ -166,6 +169,9 @@ TEST(StringConversion, ToDouble) {
   AssertConversion<DoubleType>("0", 0);
   AssertConversion<DoubleType>("-0.0", -0.0);
   AssertConversion<DoubleType>("-1e100", -1e100);
+  AssertConversion<DoubleType>("2e308", std::numeric_limits<double>::infinity());
+  AssertConversion<DoubleType>("-2e308", -std::numeric_limits<double>::infinity());
+  AssertConversion<DoubleType>("1e-325", 0.0);
   AssertConversion<DoubleType>("+Infinity", std::numeric_limits<double>::infinity());
   AssertConversion<DoubleType>("-Infinity", -std::numeric_limits<double>::infinity());
   AssertConversion<DoubleType>("Infinity", std::numeric_limits<double>::infinity());
@@ -185,6 +191,9 @@ TEST(StringConversion, ToHalfFloat) {
   AssertConversion<HalfFloatType>("0", Float16(0.0f));
   AssertConversion<HalfFloatType>("-0.0", Float16(-0.0f));
   AssertConversion<HalfFloatType>("-1e15", Float16(-1e15));
+  AssertConversion<HalfFloatType>("7e4", Float16::FromBits(0x7c00));
+  AssertConversion<HalfFloatType>("-7e4", Float16::FromBits(0xfc00));
+  AssertConversion<HalfFloatType>("1e-9", Float16(0.0f));
   AssertConversion<HalfFloatType>("+Infinity", Float16::FromBits(0x7c00));
   AssertConversion<HalfFloatType>("-Infinity", Float16::FromBits(0xfc00));
   AssertConversion<HalfFloatType>("Infinity", Float16::FromBits(0x7c00));
