refactor each solver in separate function

Author: jaja360

benchmarks/CMakeLists.txt

@@ -15,18 +15,27 @@ int main(void) {
     return 0;
 }
 " from_chars_ok)
-
-if (from_chars_ok)
-    target_compile_definitions(benchmark PUBLIC FROM_CHARS_SUPPORTED=1)
-endif()
+target_compile_definitions(benchmark PUBLIC FROM_CHARS_SUPPORTED=$<IF:${from_chars_ok},1,0>)
 
 if (NOT WIN32)
     target_link_libraries(benchmark PUBLIC netlib)
     target_compile_definitions(benchmark PUBLIC NETLIB_SUPPORTED=1)
+else()
+    target_compile_definitions(benchmark PUBLIC NETLIB_SUPPORTED=0)
 endif()
 
 if (NOT CYGWIN)
-    target_link_libraries(benchmark PUBLIC absl::strings)
+    target_link_libraries(benchmark PUBLIC absl::strings absl::str_format)
+    target_compile_definitions(benchmark PUBLIC ABSEIL_SUPPORTED=1)
+else()
+    target_compile_definitions(benchmark PUBLIC ABSEIL_SUPPORTED=0)
+endif()
+
+if(TARGET errol)
+    target_link_libraries(benchmark PUBLIC errol)
+    target_compile_definitions(benchmark PUBLIC ERROL_SUPPORTED=1)
+else()
+    target_compile_definitions(benchmark PUBLIC ERROL_SUPPORTED=0)
 endif()
 
 target_link_libraries(benchmark PUBLIC fmt)
@@ -41,7 +50,4 @@ if(teju_has_float128)
 endif()
 target_link_libraries(benchmark PUBLIC dragonbox::dragonbox_to_chars)
 target_link_libraries(benchmark PUBLIC dragon_schubfach_lib)
-if(TARGET errol)
-    target_link_libraries(benchmark PUBLIC errol)
-endif()
 target_include_directories(benchmark PUBLIC ${grisu-exact_SOURCE_DIR})

benchmarks/algorithms.h

@@ -0,0 +1,223 @@
+#ifndef ALGORITHMS_H
+#define ALGORITHMS_H
+
+#ifndef __CYGWIN__
+#include "absl/strings/str_cat.h"
+#endif
+
+#if ERROL_SUPPORTED
+#include "errol.h"
+#endif
+
+#if FROM_CHARS_SUPPORTED
+#include <charconv>
+#endif
+
+#if NETLIB_SUPPORTED
+#include <gdtoa.h>  // Netlib
+#endif
+
+#include <fmt/format.h>
+
+#include <span>
+
+#include "cpp/common/traits.hpp"  // Teju Jagua
+#include "double-conversion/double-conversion.h"
+#include "dragon4.h"
+#include "dragonbox/dragonbox_to_chars.h"
+#include "grisu2.h"
+#include "grisu_exact.h"
+#include "ieeeToString.h"
+#include "ryu/ryu.h"
+#include "schubfach_32.h"
+#include "schubfach_64.h"
+
+namespace Benchmarks {
+
+enum Algorithm {
+  DRAGON4 = 0,
+  ERROL3 = 1,
+  TO_STRING = 2,
+  FMT_FORMAT = 3,
+  NETLIB = 4,
+  SNPRINTF = 5,
+  GRISU2 = 6,
+  GRISU_EXACT = 7,
+  SCHUBFACH = 8,
+  DRAGONBOX = 9,
+  RYU = 10,
+  TEJU_JAGUA = 11,
+  DOUBLE_CONVERSION = 12,
+  ABSEIL = 13,
+  STD_TO_CHARS = 14,
+  COUNT = 15
+};
+
+template<typename T>
+concept arithmetic_float
+    = std::is_same_v<T, float> || std::is_same_v<T, double>;
+
+template<arithmetic_float T>
+struct BenchArgs {
+  using Type = T;
+
+  BenchArgs(const std::string& name = {}, int (*func)(T, std::span<char>&) = {},
+            bool used = true, unsigned char testRepeat = 100)
+      : name(name), func(func), used(used), testRepeat(testRepeat) {}
+
+  std::string name{};
+  int (*func)(T, std::span<char>&){};
+  bool used{};
+  unsigned char testRepeat{100};
+};
+
+// No dragon4 implementation optimized for float instead of double ?
+template<arithmetic_float T>
+int dragon4(T d, std::span<char>& buffer) {
+  using IEEE754Type
+      = std::conditional_t<std::is_same_v<T, float>, IEEE754f, IEEE754d>;
+  const IEEE754Type fields = decode_ieee754(d);
+
+  uint64_t dm;
+  int dexp;
+  dragon4::Dragon4(dm, dexp, fields.mantissa, fields.exponent, true, true);
+  return to_chars(dm, dexp, fields.sign, buffer.data());
+}
+
+// No errol3 implementation optimized for float instead of double ?
+template<arithmetic_float T>
+int errol3(T d, std::span<char>& buffer) {
+#if ERROL_SUPPORTED
+  errol3_dtoa(d, buffer.data());  // returns the exponent
+  return std::strlen(buffer.data());
+#else
+  std::abort();
+#endif
+}
+
+template<arithmetic_float T>
+int to_string(T d, std::span<char>& buffer) {
+  const std::string s = std::to_string(d);
+  std::copy(s.begin(), s.end(), buffer.begin());
+  return s.size();
+}
+
+template<arithmetic_float T>
+int fmt_format(T d, std::span<char>& buffer) {
+  const std::string s = fmt::format("{}", d);
+  std::copy(s.begin(), s.end(), buffer.begin());
+  return s.size();
+}
+
+// There's no "ftoa", only "dtoa", so not optimized for float.
+template<arithmetic_float T>
+int netlib(T d, std::span<char>& buffer) {
+#if NETLIB_SUPPORTED
+  int decpt, sign;
+  char* rve;
+  char* result = dtoa(d, 0, 0, &decpt, &sign, &rve);
+  if (result) {
+    const int volume = rve - result;
+    std::copy(result, rve, buffer.begin());
+    freedtoa(result);
+    return volume;
+  } else {
+    std::cerr << "problem with " << d << std::endl;
+    std::abort();
+  }
+#else
+  std::abort();
+#endif
+}
+
+template<arithmetic_float T>
+int snprintf(T d, std::span<char>& buffer) {
+  return std::snprintf(buffer.data(), buffer.size(), "%g", d);
+}
+
+// grisu2::dtoa_impl::grisu2 can take a template type
+// However, grisu2::to_chars is hardcoded for double.
+template<arithmetic_float T>
+int grisu2(T d, std::span<char>& buffer) {
+  const char* newp = grisu2::to_chars(buffer.data(), nullptr, d);
+  return newp - buffer.data();
+}
+
+template<arithmetic_float T>
+int grisu_exact(T d, std::span<char>& buffer) {
+  const auto v = jkj::grisu_exact(d);
+  return to_chars(v.significand, v.exponent, v.is_negative, buffer.data());
+}
+
+template<arithmetic_float T>
+int schubfach(T d, std::span<char>& buffer) {
+  if constexpr (std::is_same_v<T, float>)
+    return schubfach::Ftoa(buffer.data(), d) - buffer.data();
+  else
+    return schubfach::Dtoa(buffer.data(), d) - buffer.data();
+}
+
+template<arithmetic_float T>
+int dragonbox(T d, std::span<char>& buffer) {
+  const char* end_ptr = jkj::dragonbox::to_chars(d, buffer.data());
+  return end_ptr - buffer.data();
+}
+
+template<arithmetic_float T>
+int ryu(T d, std::span<char>& buffer) {
+  if constexpr (std::is_same_v<T, float>)
+    return f2s_buffered_n(d, buffer.data());
+  else
+    return d2s_buffered_n(d, buffer.data());
+}
+
+template<arithmetic_float T>
+int teju_jagua(T d, std::span<char>& buffer) {
+  const auto fields = teju::traits_t<T>::teju(d);
+  const bool sign = std::signbit(d);
+  return to_chars(fields.mantissa, fields.exponent, sign, buffer.data());
+}
+
+template<arithmetic_float T>
+int double_conversion(T d, std::span<char>& buffer) {
+  const static double_conversion::DoubleToStringConverter converter(
+      double_conversion::DoubleToStringConverter::NO_FLAGS, "inf", "nan", 'e',
+      -4, 6, 0, 0);
+  double_conversion::StringBuilder builder(buffer.data(), buffer.size());
+  const bool valid = std::is_same_v<T, float>
+                         ? converter.ToShortestSingle(d, &builder)
+                         : converter.ToShortest(d, &builder);
+  if (!valid) {
+    std::cerr << "problem with " << d << std::endl;
+    std::abort();
+  }
+  return strlen(builder.Finalize());
+}
+
+template<arithmetic_float T>
+int abseil(T d, std::span<char>& buffer) {
+  std::string s;
+  absl::StrAppend(&s, d);
+  std::copy(s.begin(), s.end(), buffer.begin());
+  return size(s);
+  // return absl::SNPrintF(buffer.data(), buffer.size(), "%g", d);
+}
+
+template<arithmetic_float T>
+int std_to_chars(T d, std::span<char>& buffer) {
+#if FROM_CHARS_SUPPORTED
+  const auto [p, ec]
+      = std::to_chars(buffer.data(), buffer.data() + buffer.size(), d);
+  if (ec != std::errc()) {
+    std::cerr << "problem with " << d << std::endl;
+    std::abort();
+  }
+  return p - buffer.data();
+#else
+  std::abort();
+#endif
+}
+
+}  // namespace Benchmarks
+
+#endif