Remove some unnecessary string copy related to substr.

Patch By: phosit
Differential Revision: https://code.wildfiregames.com/D4772
This was SVN commit r27271.

source/ps/CConsole.cpp

@@ -41,6 +41,7 @@
 #include "scriptinterface/ScriptInterface.h"
 #include "scriptinterface/JSON.h"
 
+#include <string_view>
 #include <vector>
 #include <wctype.h>
 
@@ -548,7 +549,8 @@ void CConsole::InsertMessage(const std::string& message)
 			m_MsgHistory.push_front(wrapAround.substr(oldNewline, distance));
 			oldNewline += distance+1;
 		}
-		m_MsgHistory.push_front(wrapAround.substr(oldNewline));
+		wrapAround.erase(0, oldNewline);
+		m_MsgHistory.push_front(std::move(wrapAround));
 	}
 }
 
@@ -615,7 +617,7 @@ void CConsole::LoadHistory()
 		{
 			if (pos > 0)
 				m_BufHistory.push_front(str.Left(str[pos-1] == '\r' ? pos - 1 : pos));
-			str = str.substr(pos + 1);
+			str.erase(0, pos + 1);
 		}
 		else if (str.length() > 0)
 			m_BufHistory.push_front(str);

source/ps/TemplateLoader.cpp

@@ -40,7 +40,7 @@ bool CTemplateLoader::LoadTemplateFile(CParamNode& node, std::string_view templa
 	// Handle infinite loops more gracefully than running out of stack space and crashing
 	if (depth > 100)
 	{
-		LOGERROR("Probable infinite inheritance loop in entity template '%s'", std::string(templateName));
+		LOGERROR("Probable infinite inheritance loop in entity template '%s'", templateName);
 		return false;
 	}
 

source/ps/XMB/XMBStorage.cpp

@@ -28,6 +28,7 @@
 #include "scriptinterface/ScriptInterface.h"
 
 #include <libxml/parser.h>
+#include <string_view>
 #include <unordered_map>
 
 const char* XMBStorage::HeaderMagicStr = "XMB0";
@@ -235,7 +236,8 @@ bool JSNodeData::Setup(XMBStorageWriter& xmb, JS::HandleValue value)
 		std::string_view name = prop;
 		if (!attrib && !prop.empty() && prop.back() == '@')
 		{
-			size_t idx = prop.substr(0, prop.size()-1).find_last_of('@');
+			const size_t idx = std::string_view{prop}.substr(0, prop.size() - 1)
+				.find_last_of('@');
 			if (idx == std::string::npos)
 			{
 				LOGERROR("Object key name cannot end with an '@' unless it is an index specifier.");

source/ps/tests/test_CLogger.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2009 Wildfire Games.
+/* Copyright (C) 2022 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -85,7 +85,7 @@ public:
 		std::string s = mainlog->str();
 		size_t start = s.find(header_end);
 		TS_ASSERT_DIFFERS(start, s.npos);
-		s = s.substr(start + header_end.length());
+		s.erase(0, start + header_end.length());
 
 		size_t n = 0, m;
 		while (s.npos != (m = s.find('\n', n)))