Codechange: remove char* from base driver code

src/driver.cpp

@@ -8,6 +8,7 @@
 /** @file driver.cpp Base for all driver handling. */
 
 #include "stdafx.h"
+#include "core/string_consumer.hpp"
 #include "debug.h"
 #include "error.h"
 #include "error_func.h"
@@ -43,18 +44,18 @@ static const std::string HWACCELERATION_TEST_FILE = "hwaccel.dat"; ///< Filename
  * @param name The parameter name we're looking for.
  * @return The parameter value.
  */
-const char *GetDriverParam(const StringList &parm, const char *name)
+std::optional<std::string_view> GetDriverParam(const StringList &parm, std::string_view name)
 {
-	if (parm.empty()) return nullptr;
+	if (parm.empty()) return std::nullopt;
 
-	size_t len = strlen(name);
 	for (auto &p : parm) {
-		if (p.compare(0, len, name) == 0) {
+		StringConsumer consumer{p};
-			if (p.length() == len) return "";
+		if (consumer.ReadIf(name)) {
-			if (p[len] == '=') return p.c_str() + len + 1;
+			if (!consumer.AnyBytesLeft()) return "";
+			if (consumer.ReadIf("=")) return consumer.GetLeftData();
 		}
 	}
-	return nullptr;
+	return std::nullopt;
 }
 
 /**
@@ -63,9 +64,9 @@ const char *GetDriverParam(const StringList &parm, const char *name)
  * @param name The parameter name we're looking for.
  * @return The parameter value.
  */
-bool GetDriverParamBool(const StringList &parm, const char *name)
+bool GetDriverParamBool(const StringList &parm, std::string_view name)
 {
-	return GetDriverParam(parm, name) != nullptr;
+	return GetDriverParam(parm, name).has_value();
 }
 
 /**
@@ -75,13 +76,13 @@ bool GetDriverParamBool(const StringList &parm, const char *name)
  * @param def  The default value if the parameter doesn't exist.
  * @return The parameter value.
  */
-int GetDriverParamInt(const StringList &parm, const char *name, int def)
+int GetDriverParamInt(const StringList &parm, std::string_view name, int def)
 {
-	const char *p = GetDriverParam(parm, name);
+	auto p = GetDriverParam(parm, name);
-	if (p == nullptr) return def;
+	if (!p.has_value()) return def;
-	auto value = ParseInteger<int>(p);
+	auto value = ParseInteger<int>(*p);
 	if (value.has_value()) return *value;
-	UserError("Invalid value for driver parameter {}: {}", name, p);
+	UserError("Invalid value for driver parameter {}: {}", name, *p);
 }
 
 /**
@@ -241,7 +242,7 @@ void DriverFactoryBase::GetDriversInfo(std::back_insert_iterator<std::string> &o
  * @param name        The name of the driver.
  * @param description A long-ish description of the driver.
  */
-DriverFactoryBase::DriverFactoryBase(Driver::Type type, int priority, const char *name, const char *description) :
+DriverFactoryBase::DriverFactoryBase(Driver::Type type, int priority, std::string_view name, std::string_view description) :
 	type(type), priority(priority), name(name), description(description)
 {
 	/* Prefix the name with driver type to make it unique */

src/driver.h

@@ -13,9 +13,9 @@
 #include "core/enum_type.hpp"
 #include "string_type.h"
 
-const char *GetDriverParam(const StringList &parm, const char *name);
+std::optional<std::string_view> GetDriverParam(const StringList &parm, std::string_view name);
-bool GetDriverParamBool(const StringList &parm, const char *name);
+bool GetDriverParamBool(const StringList &parm, std::string_view name);
-int GetDriverParamInt(const StringList &parm, const char *name, int def);
+int GetDriverParamInt(const StringList &parm, std::string_view name, int def);
 
 /** A driver for communicating with the user. */
 class Driver {
@@ -103,7 +103,7 @@ private:
 	static void MarkVideoDriverOperational();
 
 protected:
-	DriverFactoryBase(Driver::Type type, int priority, const char *name, const char *description);
+	DriverFactoryBase(Driver::Type type, int priority, std::string_view name, std::string_view description);
 
 	virtual ~DriverFactoryBase();
 

src/music/dmusic.cpp

@@ -78,7 +78,7 @@ struct DLSFile {
 	std::vector<DLSWave> waves;
 
 	/** Try loading a DLS file into memory. */
-	bool LoadFile(const std::string &file);
+	bool LoadFile(std::string_view file);
 
 private:
 	/** Load an articulation structure from a DLS file. */
@@ -422,7 +422,7 @@ bool DLSFile::ReadDLSWaveList(FileHandle &f, DWORD list_length)
 	return true;
 }
 
-bool DLSFile::LoadFile(const std::string &file)
+bool DLSFile::LoadFile(std::string_view file)
 {
 	Debug(driver, 2, "DMusic: Try to load DLS file {}", file);
 
@@ -843,7 +843,7 @@ static void * DownloadArticulationData(int base_offset, void *data, const std::v
 	return (CONNECTION *)(con_list + 1) + artic.size();
 }
 
-static const char *LoadDefaultDLSFile(const char *user_dls)
+static std::optional<std::string_view> LoadDefaultDLSFile(std::optional<std::string_view> user_dls)
 {
 	DMUS_PORTCAPS caps;
 	MemSetT(&caps, 0);
@@ -854,7 +854,7 @@ static const char *LoadDefaultDLSFile(const char *user_dls)
 	if ((caps.dwFlags & (DMUS_PC_DLS | DMUS_PC_DLS2)) != 0 && (caps.dwFlags & DMUS_PC_GMINHARDWARE) == 0) {
 		DLSFile dls_file;
 
-		if (user_dls == nullptr) {
+		if (!user_dls.has_value()) {
 			/* Try loading the default GM DLS file stored in the registry. */
 			HKEY hkDM;
 			if (SUCCEEDED(RegOpenKeyEx(HKEY_LOCAL_MACHINE, L"Software\\Microsoft\\DirectMusic", 0, KEY_READ, &hkDM))) {
@@ -877,7 +877,7 @@ static const char *LoadDefaultDLSFile(const char *user_dls)
 				if (!dls_file.LoadFile(FS2OTTD(path))) return "Can't load GM DLS collection";
 			}
 		} else {
-			if (!dls_file.LoadFile(user_dls)) return "Can't load GM DLS collection";
+			if (!dls_file.LoadFile(*user_dls)) return "Can't load GM DLS collection";
 		}
 
 		/* Get download port and allocate download IDs. */
@@ -1060,7 +1060,7 @@ static const char *LoadDefaultDLSFile(const char *user_dls)
 		download_port->Release();
 	}
 
-	return nullptr;
+	return std::nullopt;
 }
 
 
@@ -1136,8 +1136,8 @@ std::optional<std::string_view> MusicDriver_DMusic::Start(const StringList &parm
 	if (FAILED(_music->CreateMusicBuffer(&desc, &_buffer, nullptr))) return "Failed to create music buffer";
 
 	/* On soft-synths (e.g. the default DirectMusic one), we might need to load a wavetable set to get music. */
-	const char *dls = LoadDefaultDLSFile(GetDriverParam(parm, "dls"));
+	auto dls = LoadDefaultDLSFile(GetDriverParam(parm, "dls"));
-	if (dls != nullptr) return dls;
+	if (dls.has_value()) return dls;
 
 	/* Create playback thread and synchronization primitives. */
 	_thread_event = CreateEvent(nullptr, FALSE, FALSE, nullptr);

src/music/extmidi.cpp

@@ -43,22 +43,21 @@ std::optional<std::string_view> MusicDriver_ExtMidi::Start(const StringList &par
 		return "the extmidi driver does not work when Allegro is loaded.";
 	}
 
-	const char *command = GetDriverParam(parm, "cmd");
+	auto command = GetDriverParam(parm, "cmd");
 #ifndef MIDI_ARG
-	if (StrEmpty(command)) command = EXTERNAL_PLAYER;
+	if (!command.has_value() || command->empty()) command = EXTERNAL_PLAYER;
 #else
-	if (StrEmpty(command)) command = EXTERNAL_PLAYER " " MIDI_ARG;
+	if (!command.has_value() || command->empty()) command = EXTERNAL_PLAYER " " MIDI_ARG;
 #endif
 
 	this->command_tokens.clear();
 
-	std::string_view view = command;
 	for (;;) {
-		auto pos = view.find(' ');
+		auto pos = command->find(' ');
-		this->command_tokens.emplace_back(view.substr(0, pos));
+		this->command_tokens.emplace_back(command->substr(0, pos));
 
 		if (pos == std::string_view::npos) break;
-		view.remove_prefix(pos + 1);
+		command->remove_prefix(pos + 1);
 	}
 
 	this->song.clear();

src/music/fluidsynth.cpp

@@ -63,10 +63,10 @@ std::optional<std::string_view> MusicDriver_FluidSynth::Start(const StringList &
 {
 	std::lock_guard<std::mutex> lock{ _midi.synth_mutex };
 
-	const char *sfont_name = GetDriverParam(param, "soundfont");
+	auto sfont_name = GetDriverParam(param, "soundfont");
 	int sfont_id;
 
-	Debug(driver, 1, "Fluidsynth: sf {}", sfont_name != nullptr ? sfont_name : "(null)");
+	Debug(driver, 1, "Fluidsynth: sf {}", sfont_name.has_value() ? *sfont_name : "(null)");
 
 	/* Create the settings. */
 	_midi.settings = new_fluid_settings();
@@ -85,7 +85,7 @@ std::optional<std::string_view> MusicDriver_FluidSynth::Start(const StringList &
 
 	/* Load a SoundFont and reset presets (so that new instruments
 	 * get used from the SoundFont) */
-	if (sfont_name == nullptr) {
+	if (!sfont_name.has_value()) {
 		sfont_id = FLUID_FAILED;
 
 		/* Try loading the default soundfont registered with FluidSynth. */
@@ -105,7 +105,8 @@ std::optional<std::string_view> MusicDriver_FluidSynth::Start(const StringList &
 		}
 		if (sfont_id == FLUID_FAILED) return "Could not open any sound font";
 	} else {
-		sfont_id = fluid_synth_sfload(_midi.synth, sfont_name, 1);
+		std::string name{sfont_name};
+		sfont_id = fluid_synth_sfload(_midi.synth, name.c_str(), 1);
 		if (sfont_id == FLUID_FAILED) return "Could not open sound font";
 	}
 

src/music/win32_m.cpp

@@ -372,10 +372,10 @@ std::optional<std::string_view> MusicDriver_Win32::Start(const StringList &parm)
 
 	int resolution = GetDriverParamInt(parm, "resolution", 5);
 	uint port = (uint)GetDriverParamInt(parm, "port", UINT_MAX);
-	const char *portname = GetDriverParam(parm, "portname");
+	auto portname = GetDriverParam(parm, "portname");
 
 	/* Enumerate ports either for selecting port by name, or for debug output */
-	if (portname != nullptr || _debug_driver_level > 0) {
+	if (portname.has_value() || _debug_driver_level > 0) {
 		uint numports = midiOutGetNumDevs();
 		Debug(driver, 1, "Win32-MIDI: Found {} output devices:", numports);
 		for (uint tryport = 0; tryport < numports; tryport++) {
@@ -386,7 +386,7 @@ std::optional<std::string_view> MusicDriver_Win32::Start(const StringList &parm)
 
 				/* Compare requested and detected port name.
 				 * If multiple ports have the same name, this will select the last matching port, and the debug output will be confusing. */
-				if (portname != nullptr && strncmp(tryportname, portname, lengthof(tryportname)) == 0) port = tryport;
+				if (portname.has_value() && *portname == tryportname) port = tryport;
 
 				Debug(driver, 1, "MIDI port {:2d}: {}{}", tryport, tryportname, (tryport == port) ? " [selected]" : "");
 			}

src/sound/win32_s.cpp

@@ -39,7 +39,7 @@ static void PrepareHeader(HeaderDataPair &hdr)
 	hdr.first.dwBufferLength = _bufsize * 4;
 	hdr.first.dwFlags = 0;
 	hdr.first.lpData = hdr.second.get();
-	if (waveOutPrepareHeader(_waveout, &hdr.first, sizeof(WAVEHDR)) != MMSYSERR_NOERROR) throw "waveOutPrepareHeader failed";
+	if (waveOutPrepareHeader(_waveout, &hdr.first, sizeof(WAVEHDR)) != MMSYSERR_NOERROR) throw "waveOutPrepareHeader failed"sv;
 }
 
 static DWORD WINAPI SoundThread(LPVOID)
@@ -76,16 +76,16 @@ std::optional<std::string_view> SoundDriver_Win32::Start(const StringList &parm)
 	_bufsize = std::min<int>(_bufsize, UINT16_MAX);
 
 	try {
-		if (nullptr == (_event = CreateEvent(nullptr, FALSE, FALSE, nullptr))) throw "Failed to create event";
+		if (nullptr == (_event = CreateEvent(nullptr, FALSE, FALSE, nullptr))) throw "Failed to create event"sv;
 
-		if (waveOutOpen(&_waveout, WAVE_MAPPER, &wfex, (DWORD_PTR)_event, 0, CALLBACK_EVENT) != MMSYSERR_NOERROR) throw "waveOutOpen failed";
+		if (waveOutOpen(&_waveout, WAVE_MAPPER, &wfex, (DWORD_PTR)_event, 0, CALLBACK_EVENT) != MMSYSERR_NOERROR) throw "waveOutOpen failed"sv;
 
 		MxInitialize(wfex.nSamplesPerSec);
 
 		for (auto &hdr : _wave_hdr) PrepareHeader(hdr);
 
-		if (nullptr == (_thread = CreateThread(nullptr, 8192, SoundThread, 0, 0, &_threadId))) throw "Failed to create thread";
+		if (nullptr == (_thread = CreateThread(nullptr, 8192, SoundThread, 0, 0, &_threadId))) throw "Failed to create thread"sv;
-	} catch (const char *error) {
+	} catch (std::string_view error) {
 		this->Stop();
 		return error;
 	}