From 8445327c84dd0bfd23646dc2d92fed105b8fae8c Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@meta.com>
Date: Thu, 1 Aug 2024 19:30:30 -0700
Subject: [PATCH] Simplify spec handling

---
 include/fmt/base.h   |  1 -
 include/fmt/format.h | 36 +++++++++++++-----------------------
 test/base-test.cc    |  2 +-
 3 files changed, 14 insertions(+), 25 deletions(-)

diff --git a/include/fmt/base.h b/include/fmt/base.h
index 4c9525e9..141ffe08 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -2430,7 +2430,6 @@ FMT_CONSTEXPR auto parse_format_specs(const Char* begin, const Char* end,
         specs.sign = sign::plus;
         break;
       case '-':
-        specs.sign = sign::minus;
         break;
       case ' ':
         specs.sign = sign::space;
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 2cab8939..b0976f47 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3165,11 +3165,10 @@ FMT_CONSTEXPR20 auto format_float(Float value, int precision,
                                   buffer<char>& buf) -> int {
   // float is passed as double to reduce the number of instantiations.
   static_assert(!std::is_same<Float, float>::value, "");
-  FMT_ASSERT(value >= 0, "value is negative");
   auto converted_value = convert_float(value);
 
   const bool fixed = specs.type == presentation_type::fixed;
-  if (value <= 0) {  // <= instead of == to silence a warning.
+  if (value == 0) {
     if (precision <= 0 || !fixed) {
       buf.push_back('0');
       return 0;
@@ -3462,13 +3461,8 @@ FMT_CONSTEXPR20 auto format_float(Float value, int precision,
 template <typename Char, typename OutputIt, typename T>
 FMT_CONSTEXPR20 auto write_float(OutputIt out, T value, format_specs specs,
                                  locale_ref loc) -> OutputIt {
-  sign_t sign = specs.sign;
-  if (detail::signbit(value)) {  // value < 0 is false for NaN so use signbit.
-    sign = sign::minus;
-    value = -value;
-  } else if (sign == sign::minus) {
-    sign = sign::none;
-  }
+  // Use signbit because value < 0 is false for NaN.
+  sign_t sign = detail::signbit(value) ? sign::minus : specs.sign;
 
   if (!detail::isfinite(value))
     return write_nonfinite<Char>(out, detail::isnan(value), specs, sign);
@@ -3479,14 +3473,6 @@ FMT_CONSTEXPR20 auto write_float(OutputIt out, T value, format_specs specs,
     if (specs.width != 0) --specs.width;
   }
 
-  memory_buffer buffer;
-  if (specs.type == presentation_type::hexfloat) {
-    if (sign) buffer.push_back(detail::sign<char>(sign));
-    format_hexfloat(convert_float(value), specs, buffer);
-    return write_bytes<Char, align::right>(out, {buffer.data(), buffer.size()},
-                                           specs);
-  }
-
   int precision = specs.precision;
   if (precision < 0) {
     if (specs.type != presentation_type::none) {
@@ -3499,6 +3485,14 @@ FMT_CONSTEXPR20 auto write_float(OutputIt out, T value, format_specs specs,
     }
   }
 
+  memory_buffer buffer;
+  if (specs.type == presentation_type::hexfloat) {
+    if (sign) buffer.push_back(detail::sign<char>(sign));
+    format_hexfloat(convert_float(value), specs, buffer);
+    return write_bytes<Char, align::right>(out, {buffer.data(), buffer.size()},
+                                           specs);
+  }
+
   if (specs.type == presentation_type::exp) {
     if (precision == max_value<int>())
       report_error("number is too big");
@@ -3534,14 +3528,10 @@ FMT_CONSTEXPR20 auto write(OutputIt out, T value) -> OutputIt {
   if (is_constant_evaluated()) return write<Char>(out, value, format_specs());
   if (const_check(!is_supported_floating_point(value))) return out;
 
-  auto sign = sign_t::none;
-  if (detail::signbit(value)) {
-    sign = sign::minus;
-    value = -value;
-  }
+  auto sign = detail::signbit(value) ? sign::minus : sign_t::none;
 
   constexpr auto specs = format_specs();
-  using floaty = conditional_t<std::is_same<T, long double>::value, double, T>;
+  using floaty = conditional_t<sizeof(T) >= sizeof(double), double, float>;
   using floaty_uint = typename dragonbox::float_info<floaty>::carrier_uint;
   floaty_uint mask = exponent_mask<floaty>();
   if ((bit_cast<floaty_uint>(value) & mask) == mask)
diff --git a/test/base-test.cc b/test/base-test.cc
index 4afd99da..0c49494d 100644
--- a/test/base-test.cc
+++ b/test/base-test.cc
@@ -519,7 +519,7 @@ TEST(base_test, constexpr_parse_format_specs) {
   static_assert(parse_test_specs("<").align == fmt::align::left, "");
   static_assert(parse_test_specs("*^").fill.get<char>() == '*', "");
   static_assert(parse_test_specs("+").sign == fmt::sign::plus, "");
-  static_assert(parse_test_specs("-").sign == fmt::sign::minus, "");
+  static_assert(parse_test_specs("-").sign == fmt::sign::none, "");
   static_assert(parse_test_specs(" ").sign == fmt::sign::space, "");
   static_assert(parse_test_specs("#").alt, "");
   static_assert(parse_test_specs("0").align == fmt::align::numeric, "");