From b0821cff553581d6499f5e542cd795f20c3e9bc7 Mon Sep 17 00:00:00 2001
From: Kp <kp@valhallalegends.com>
Date: Fri, 22 Jul 2016 02:25:17 +0000
Subject: [PATCH] Fix inverted sense of -use_players_dir

Fixes: 4d483ca88f6f27589b287c23d03626dc2d0426c5 ("Simplify use of SysUsePlayersDir")
---
 common/include/args.h    |  4 ++--
 similar/main/inferno.cpp | 15 +++++++++------
 similar/misc/args.cpp    |  2 +-
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/common/include/args.h b/common/include/args.h
index e00c8eb31..d57e422f3 100644
--- a/common/include/args.h
+++ b/common/include/args.h
@@ -74,7 +74,7 @@ struct CArg : prohibit_void_ptr<CArg>
 #endif
 	bool SysShowCmdHelp;
 	bool SysLowMem;
-	uint8_t SysUsePlayersDir;
+	int8_t SysUsePlayersDir;
 	bool SysAutoRecordDemo;
 	bool SysWindow;
 	bool SysAutoDemo;
@@ -162,7 +162,7 @@ __attribute_format_arg(1)
 static inline const char *PLAYER_DIRECTORY_STRING(const char *s);
 static inline const char *PLAYER_DIRECTORY_STRING(const char *s)
 {
-	return &s[CGameArg.SysUsePlayersDir];
+	return &s[CGameArg.SysUsePlayersDir + sizeof(PLAYER_DIRECTORY_TEXT) - 1];
 }
 #define PLAYER_DIRECTORY_STRING(S)	((PLAYER_DIRECTORY_STRING)(PLAYER_DIRECTORY_TEXT S))
 }
diff --git a/similar/main/inferno.cpp b/similar/main/inferno.cpp
index b6d0f158c..878ca0d76 100644
--- a/similar/main/inferno.cpp
+++ b/similar/main/inferno.cpp
@@ -536,17 +536,22 @@ static int main(int argc, char *argv[])
 		{
 			char filename[sizeof(PLAYER_DIRECTORY_TEXT) + CALLSIGN_LEN + 4];
 
+			/* Step over the literal PLAYER_DIRECTORY_TEXT when it is
+			 * present.  Point at &filename[0] when
+			 * PLAYER_DIRECTORY_TEXT is absent.
+			 */
+			const auto b = &filename[-CGameArg.SysUsePlayersDir];
 			snprintf(filename, sizeof(filename), PLAYER_DIRECTORY_STRING("%.12s"), CGameArg.SysPilot.c_str());
 			/* The pilot name is never used after this.  Clear it to
 			 * free the allocated memory, if any.
 			 */
 			CGameArg.SysPilot.clear();
-			const uintptr_t SysUsePlayersDir = CGameArg.SysUsePlayersDir;
-			auto j = SysUsePlayersDir;
-			for (const auto &facet = std::use_facet<std::ctype<char>>(std::locale::classic()); char &c = filename[j]; ++j)
+			auto p = b;
+			for (const auto &facet = std::use_facet<std::ctype<char>>(std::locale::classic()); char &c = *p; ++p)
 			{
 				c = facet.tolower(static_cast<uint8_t>(c));
 			}
+			auto j = p - filename;
 			if (j < sizeof(filename) - 4 && (j <= 4 || strcmp(&filename[j - 4], ".plr"))) // if player hasn't specified .plr extension in argument, add it
 			{
 				strcpy(&filename[j], ".plr");
@@ -554,9 +559,7 @@ static int main(int argc, char *argv[])
 			}
 			if(PHYSFSX_exists(filename,0))
 			{
-				filename[j - 4] = 0;
-				const auto b = &filename[SysUsePlayersDir];
-				get_local_player().callsign.copy(b, std::distance(b, end(filename)));
+				get_local_player().callsign.copy(b, std::distance(b, &filename[j - 4]));
 				read_player_file();
 				WriteConfigFile();
 			}
diff --git a/similar/misc/args.cpp b/similar/misc/args.cpp
index b743c13df..f57359f29 100644
--- a/similar/misc/args.cpp
+++ b/similar/misc/args.cpp
@@ -218,7 +218,7 @@ static void ReadCmdArgs(Inilist &ini, Arglist &Args)
 #endif
 		}
 		else if (!d_stricmp(p, "-use_players_dir"))
-			CGameArg.SysUsePlayersDir = sizeof(PLAYER_DIRECTORY_TEXT) - 1;
+			CGameArg.SysUsePlayersDir = static_cast<int8_t>(- (sizeof(PLAYER_DIRECTORY_TEXT) - 1));
 		else if (!d_stricmp(p, "-lowmem"))
 			CGameArg.SysLowMem = true;
 		else if (!d_stricmp(p, "-pilot"))