From 0e8d4cb6ac679fd52a320aae9d1a478e47728116 Mon Sep 17 00:00:00 2001
From: Jordan Woyak <jordan.woyak@gmail.com>
Date: Mon, 30 Dec 2019 17:28:35 -0600
Subject: [PATCH] StringUtil: Make TryParse of floats handle comma and dot
 decimal separators.

---
 Source/Core/Common/StringUtil.cpp | 45 ----------------------
 Source/Core/Common/StringUtil.h   | 63 +++++++++++++++++++++++++------
 2 files changed, 52 insertions(+), 56 deletions(-)

diff --git a/Source/Core/Common/StringUtil.cpp b/Source/Core/Common/StringUtil.cpp
index 3eeb6d04fe..2369208f45 100644
--- a/Source/Core/Common/StringUtil.cpp
+++ b/Source/Core/Common/StringUtil.cpp
@@ -235,51 +235,6 @@ std::string_view StripQuotes(std::string_view s)
     return s;
 }
 
-bool TryParse(const std::string& str, u16* const output)
-{
-  u64 value;
-  if (!TryParse(str, &value))
-    return false;
-
-  if (value >= 0x10000ull && value <= 0xFFFFFFFFFFFF0000ull)
-    return false;
-
-  *output = static_cast<u16>(value);
-  return true;
-}
-
-bool TryParse(const std::string& str, u32* const output)
-{
-  u64 value;
-  if (!TryParse(str, &value))
-    return false;
-
-  if (value >= 0x100000000ull && value <= 0xFFFFFFFF00000000ull)
-    return false;
-
-  *output = static_cast<u32>(value);
-  return true;
-}
-
-bool TryParse(const std::string& str, u64* const output)
-{
-  char* end_ptr = nullptr;
-
-  // Set errno to a clean slate
-  errno = 0;
-
-  u64 value = strtoull(str.c_str(), &end_ptr, 0);
-
-  if (end_ptr == nullptr || *end_ptr != '\0')
-    return false;
-
-  if (errno == ERANGE)
-    return false;
-
-  *output = value;
-  return true;
-}
-
 bool TryParse(const std::string& str, bool* const output)
 {
   float value;
diff --git a/Source/Core/Common/StringUtil.h b/Source/Core/Common/StringUtil.h
index b651910767..c47fd1f620 100644
--- a/Source/Core/Common/StringUtil.h
+++ b/Source/Core/Common/StringUtil.h
@@ -6,7 +6,9 @@
 
 #include <cstdarg>
 #include <cstddef>
+#include <cstdlib>
 #include <iomanip>
+#include <locale>
 #include <sstream>
 #include <string>
 #include <type_traits>
@@ -47,20 +49,60 @@ std::string ArrayToString(const u8* data, u32 size, int line_len = 20, bool spac
 std::string_view StripSpaces(std::string_view s);
 std::string_view StripQuotes(std::string_view s);
 
+std::string ReplaceAll(std::string result, std::string_view src, std::string_view dest);
+
 bool TryParse(const std::string& str, bool* output);
-bool TryParse(const std::string& str, u16* output);
-bool TryParse(const std::string& str, u32* output);
-bool TryParse(const std::string& str, u64* output);
 
-template <typename N>
-static bool TryParse(const std::string& str, N* const output)
+template <typename T, std::enable_if_t<std::is_integral_v<T> || std::is_enum_v<T>>* = nullptr>
+bool TryParse(const std::string& str, T* output)
 {
-  std::istringstream iss(str);
-  // is this right? not doing this breaks reading floats on locales that use different decimal
-  // separators
-  iss.imbue(std::locale("C"));
+  char* end_ptr = nullptr;
 
-  N tmp;
+  // Set errno to a clean slate.
+  errno = 0;
+
+  // Read a u64 for unsigned types and s64 otherwise.
+  using ReadType = std::conditional_t<std::is_unsigned_v<T>, u64, s64>;
+  ReadType value;
+
+  if constexpr (std::is_unsigned_v<T>)
+    value = std::strtoull(str.c_str(), &end_ptr, 0);
+  else
+    value = std::strtoll(str.c_str(), &end_ptr, 0);
+
+  // Fail if the end of the string wasn't reached.
+  if (end_ptr == nullptr || *end_ptr != '\0')
+    return false;
+
+  // Fail if the value was out of 64-bit range.
+  if (errno == ERANGE)
+    return false;
+
+  using LimitsType = typename std::conditional_t<std::is_enum_v<T>, std::underlying_type<T>,
+                                                 std::common_type<T>>::type;
+  // Fail if outside numeric limits.
+  if (value < std::numeric_limits<LimitsType>::min() ||
+      value > std::numeric_limits<LimitsType>::max())
+  {
+    return false;
+  }
+
+  *output = static_cast<T>(value);
+  return true;
+}
+
+template <typename T, std::enable_if_t<std::is_floating_point_v<T>>* = nullptr>
+bool TryParse(std::string str, T* const output)
+{
+  // Replace commas with dots.
+  std::istringstream iss(ReplaceAll(std::move(str), ",", "."));
+
+  // Use "classic" locale to force a "dot" decimal separator.
+  iss.imbue(std::locale::classic());
+
+  T tmp;
+
+  // Succeed if a value was read and the entire string was used.
   if (iss >> tmp && iss.eof())
   {
     *output = tmp;
@@ -118,7 +160,6 @@ bool SplitPath(std::string_view full_path, std::string* path, std::string* filen
 
 void BuildCompleteFilename(std::string& complete_filename, std::string_view path,
                            std::string_view filename);
-std::string ReplaceAll(std::string result, std::string_view src, std::string_view dest);
 
 bool StringBeginsWith(std::string_view str, std::string_view begin);
 bool StringEndsWith(std::string_view str, std::string_view end);