Avoid undefined behaviour const_casting std::string c_str()

Use non-const data() instead

See: #224

src/console_cmds.cpp

@@ -2325,7 +2325,7 @@ DEF_CONSOLE_CMD(ConDumpLoadDebugLog)
 	}
 
 	std::string dbgl = _loadgame_DBGL_data;
-	PrintLineByLine(const_cast<char *>(dbgl.c_str()));
+	PrintLineByLine(dbgl.data());
 	return true;
 }
 
@@ -2337,7 +2337,7 @@ DEF_CONSOLE_CMD(ConDumpLoadDebugConfig)
 	}
 
 	std::string dbgc = _loadgame_DBGC_data;
-	PrintLineByLine(const_cast<char *>(dbgc.c_str()));
+	PrintLineByLine(dbgc.data());
 	return true;
 }
 

src/network/core/packet.cpp

@@ -11,6 +11,7 @@
 
 #include "../../stdafx.h"
 #include "../../string_func.h"
+#include "../../string_func_extra.h"
 #include "../../command_type.h"
 
 #include "packet.h"
@@ -337,7 +338,7 @@ void Packet::Recv_string(std::string &buffer, StringValidationSettings settings)
 	size_t length = ttd_strnlen((const char *)(this->buffer + this->pos), this->size - this->pos - 1);
 	buffer.assign((const char *)(this->buffer + this->pos), length);
 	this->pos += length + 1;
-	str_validate(const_cast<char *>(buffer.c_str()), buffer.c_str() + buffer.size(), settings);
+	str_validate_inplace(buffer, settings);
 }
 
 /**

src/network/network.cpp

@@ -946,7 +946,7 @@ void NetworkGameLoop()
 				cp->text.resize(MAX_CMD_TEXT_LENGTH);
 				static_assert(MAX_CMD_TEXT_LENGTH > 8192);
 				int ret = sscanf(p, "date{%x; %x; %x}; company: %x; tile: %x (%*u x %*u); p1: %x; p2: %x; p3: " OTTD_PRINTFHEX64 "; cmd: %x; \"%8192[^\"]\"",
-						&next_date, &next_date_fract, &next_tick_skip_counter, &company, &cp->tile, &cp->p1, &cp->p2, &cp->p3, &cp->cmd, const_cast<char *>(cp->text.c_str()));
+						&next_date, &next_date_fract, &next_tick_skip_counter, &company, &cp->tile, &cp->p1, &cp->p2, &cp->p3, &cp->cmd, cp->text.data());
 				/* There are 10 pieces of data to read, however the last is a
 				 * string that might or might not exist. Ignore it if that
 				 * string misses because in 99% of the time it's not used. */

src/network/network_client.cpp

@@ -1163,7 +1163,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_DESYNC_LOG(Pack
 {
 	uint size = p->Recv_uint16();
 	this->server_desync_log.resize(this->server_desync_log.size() + size);
-	p->Recv_binary(const_cast<char *>(this->server_desync_log.data() + this->server_desync_log.size() - size), size);
+	p->Recv_binary(this->server_desync_log.data() + this->server_desync_log.size() - size, size);
 	DEBUG(net, 2, "Received %u bytes of server desync log", size);
 	return NETWORK_RECV_STATUS_OKAY;
 }

src/network/network_server.cpp

@@ -1280,7 +1280,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_DESYNC_LOG(Pack
 {
 	uint size = p->Recv_uint16();
 	this->desync_log.resize(this->desync_log.size() + size);
-	p->Recv_binary(const_cast<char *>(this->desync_log.data() + this->desync_log.size() - size), size);
+	p->Recv_binary(this->desync_log.data() + this->desync_log.size() - size, size);
 	DEBUG(net, 2, "Received %u bytes of client desync log", size);
 	this->receive_limit += p->size;
 	return NETWORK_RECV_STATUS_OKAY;

src/openttd.cpp

@@ -353,7 +353,7 @@ static void WriteSavegameDebugData(const char *name)
 	if (_load_check_data.debug_log_data.size()) {
 		p += seprintf(p, buflast, "%u bytes of debug log data in savegame\n", (uint) _load_check_data.debug_log_data.size());
 		std::string buffer = _load_check_data.debug_log_data;
-		ProcessLineByLine(const_cast<char *>(buffer.data()), [&](const char *line) {
+		ProcessLineByLine(buffer.data(), [&](const char *line) {
 			if (buflast - p <= 1024) bump_size();
 			p += seprintf(p, buflast, "> %s\n", line);
 		});
@@ -363,7 +363,7 @@ static void WriteSavegameDebugData(const char *name)
 	if (_load_check_data.debug_config_data.size()) {
 		p += seprintf(p, buflast, "%u bytes of debug config data in savegame\n", (uint) _load_check_data.debug_config_data.size());
 		std::string buffer = _load_check_data.debug_config_data;
-		ProcessLineByLine(const_cast<char *>(buffer.data()), [&](const char *line) {
+		ProcessLineByLine(buffer.data(), [&](const char *line) {
 			if (buflast - p <= 1024) bump_size();
 			p += seprintf(p, buflast, "> %s\n", line);
 		});

src/saveload/debug_sl.cpp

@@ -32,7 +32,7 @@ static void Load_DBGL()
 	size_t length = SlGetFieldLength();
 	if (length) {
 		_loadgame_DBGL_data.resize(length);
-		ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(const_cast<char *>(_loadgame_DBGL_data.data())), length);
+		ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(_loadgame_DBGL_data.data()), length);
 	}
 }
 
@@ -45,7 +45,7 @@ static void Check_DBGL()
 	size_t length = SlGetFieldLength();
 	if (length) {
 		_load_check_data.debug_log_data.resize(length);
-		ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(const_cast<char *>(_load_check_data.debug_log_data.data())), length);
+		ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(_load_check_data.debug_log_data.data()), length);
 	}
 }
 
@@ -69,7 +69,7 @@ static void Load_DBGC()
 	size_t length = SlGetFieldLength();
 	if (length) {
 		_loadgame_DBGC_data.resize(length);
-		ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(const_cast<char *>(_loadgame_DBGC_data.data())), length);
+		ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(_loadgame_DBGC_data.data()), length);
 	}
 }
 
@@ -82,7 +82,7 @@ static void Check_DBGC()
 	size_t length = SlGetFieldLength();
 	if (length) {
 		_load_check_data.debug_config_data.resize(length);
-		ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(const_cast<char *>(_load_check_data.debug_config_data.data())), length);
+		ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(_load_check_data.debug_config_data.data()), length);
 	}
 }
 

src/saveload/extended_ver_sl.cpp

@@ -635,7 +635,7 @@ static void Load_SLXI()
 static void loadVL(const SlxiSubChunkInfo *info, uint32 length)
 {
 	_sl_xv_version_label.resize(length);
-	ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(const_cast<char *>(_sl_xv_version_label.c_str())), length);
+	ReadBuffer::GetCurrent()->CopyBytes(reinterpret_cast<byte *>(_sl_xv_version_label.data()), length);
 }
 
 static uint32 saveVL(const SlxiSubChunkInfo *info, bool dry_run)

src/saveload/saveload.cpp

@@ -1132,20 +1132,20 @@ static void SlStdString(std::string &str, VarType conv)
 	switch (_sl.action) {
 		case SLA_SAVE: {
 			SlWriteArrayLength(str.size());
-			SlCopyBytes(const_cast<char *>(str.data()), str.size());
+			SlCopyBytes(str.data(), str.size());
 			break;
 		}
 		case SLA_LOAD_CHECK:
 		case SLA_LOAD: {
 			size_t len = SlReadArrayLength();
 			str.resize(len);
-			SlCopyBytes(const_cast<char *>(str.c_str()), len);
+			SlCopyBytes(str.data(), len);
 
 			StringValidationSettings settings = SVS_REPLACE_WITH_QUESTION_MARK;
 			if ((conv & SLF_ALLOW_CONTROL) != 0) {
 				settings = settings | SVS_ALLOW_CONTROL_CODE;
 				if (IsSavegameVersionBefore(SLV_169)) {
-					char *buf = const_cast<char *>(str.c_str());
+					char *buf = str.data();
 					str.resize(str_fix_scc_encoded(buf, buf + str.size()) - buf);
 				}
 			}

src/string_func_extra.h

@@ -14,7 +14,7 @@
 static inline void str_validate_inplace(std::string &str, StringValidationSettings settings = SVS_REPLACE_WITH_QUESTION_MARK)
 {
 	if (str.empty()) return;
-	char *buf = const_cast<char *>(str.c_str());
+	char *buf = str.data();
 	str.resize(str_validate(buf, buf + str.size(), settings) - buf);
 }