From 0473beff2bef388373dabc756b829f48bb9d1a4e Mon Sep 17 00:00:00 2001
From: Treeston <treeston.mmoc@gmail.com>
Date: Sun, 23 Aug 2020 00:31:57 +0200
Subject: Core/Misc: std::string -> std::string_view in a bunch of places,
 notably chat commands and Util.h

(cherry picked from commit a41bbd9ad9adedb15c7133bdef1575a6ec0eb1ab)
---
 .../game/Chat/ChatCommands/ChatCommandArgs.h       | 76 +++++++++++-----------
 1 file changed, 39 insertions(+), 37 deletions(-)

(limited to 'src/server/game/Chat/ChatCommands')

diff --git a/src/server/game/Chat/ChatCommands/ChatCommandArgs.h b/src/server/game/Chat/ChatCommands/ChatCommandArgs.h
index a90790265ca..8a723686196 100644
--- a/src/server/game/Chat/ChatCommands/ChatCommandArgs.h
+++ b/src/server/game/Chat/ChatCommands/ChatCommandArgs.h
@@ -22,7 +22,10 @@
 #include "ChatCommandTags.h"
 #include "SmartEnum.h"
 #include "Util.h"
+#include <charconv>
 #include <map>
+#include <string>
+#include <string_view>
 
 struct GameTele;
 
@@ -43,42 +46,26 @@ namespace ChatCommands
 template <typename T, typename = void>
 struct ArgInfo { static_assert(!std::is_same_v<T,T>, "Invalid command parameter type - see ChatCommandArgs.h for possible types"); };
 
-// catch-all for signed integral types
+// catch-all for integral types
 template <typename T>
-struct ArgInfo<T, std::enable_if_t<std::is_integral_v<T> && std::is_signed_v<T>>>
+struct ArgInfo<T, std::enable_if_t<std::is_integral_v<T>>>
 {
     static char const* TryConsume(T& val, char const* args)
     {
         char const* next = args;
-        std::string token(args, Trinity::Impl::ChatCommands::tokenize(next));
-        try
-        {
-            size_t processedChars = 0;
-            val = std::stoll(token, &processedChars, 0);
-            if (processedChars != token.length())
-                return nullptr;
-        }
-        catch (...) { return nullptr; }
-        return next;
-    }
-};
+        std::string_view token(args, Trinity::Impl::ChatCommands::tokenize(next));
+
+        std::from_chars_result result;
+        if (StringStartsWith(token, "0x"))
+            result = std::from_chars(token.data() + 2, token.data() + token.length(), val, 16);
+        else if (StringStartsWith(token, "0b"))
+            result = std::from_chars(token.data() + 2, token.data() + token.length(), val, 2);
+        else
+            result = std::from_chars(token.data(), token.data() + token.length(), val, 10);
+
+        if ((token.data() + token.length()) != result.ptr)
+            return nullptr;
 
-// catch-all for unsigned integral types
-template <typename T>
-struct ArgInfo<T, std::enable_if_t<std::is_integral_v<T> && std::is_unsigned_v<T>>>
-{
-    static char const* TryConsume(T& val, char const* args)
-    {
-        char const* next = args;
-        std::string token(args, Trinity::Impl::ChatCommands::tokenize(next));
-        try
-        {
-            size_t processedChars = 0;
-            val = std::stoull(token, &processedChars, 0);
-            if (processedChars != token.length())
-                return nullptr;
-        }
-        catch (...) { return nullptr; }
         return next;
     }
 };
@@ -93,6 +80,7 @@ struct ArgInfo<T, std::enable_if_t<std::is_floating_point_v<T>>>
         std::string token(args, Trinity::Impl::ChatCommands::tokenize(next));
         try
         {
+            // @todo replace this once libc++ supports double args to from_chars for required minimum
             size_t processedChars = 0;
             val = std::stold(token, &processedChars);
             if (processedChars != token.length())
@@ -103,16 +91,16 @@ struct ArgInfo<T, std::enable_if_t<std::is_floating_point_v<T>>>
     }
 };
 
-// string
+// string_view
 template <>
-struct ArgInfo<std::string, void>
+struct ArgInfo<std::string_view, void>
 {
-    static char const* TryConsume(std::string& val, char const* args)
+    static char const* TryConsume(std::string_view& val, char const* args)
     {
         char const* next = args;
         if (size_t len = Trinity::Impl::ChatCommands::tokenize(next))
         {
-            val.assign(args, len);
+            val = std::string_view(args, len);
             return next;
         }
         else
@@ -120,19 +108,33 @@ struct ArgInfo<std::string, void>
     }
 };
 
+// string
+template <>
+struct ArgInfo<std::string, void>
+{
+    static char const* TryConsume(std::string& val, char const* args)
+    {
+        std::string_view view;
+        args = ArgInfo<std::string_view>::TryConsume(view, args);
+        if (args)
+            val.assign(view);
+        return args;
+    }
+};
+
 // wstring
 template <>
 struct ArgInfo<std::wstring, void>
 {
     static char const* TryConsume(std::wstring& val, char const* args)
     {
-        std::string utf8Str;
-        char const* ret = ArgInfo<std::string>::TryConsume(utf8Str, args);
+        std::string_view utf8view;
+        char const* ret = ArgInfo<std::string_view>::TryConsume(utf8view, args);
 
         if (!ret)
             return nullptr;
 
-        if (!Utf8toWStr(utf8Str, val))
+        if (!Utf8toWStr(utf8view, val))
             return nullptr;
 
         return ret;
-- 
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