Codechange: make the StringIndex (within a StringTab) a strong type

src/game/game_text.cpp

@@ -315,10 +315,10 @@ GameStrings *_current_data = nullptr;
  * @param id The ID of the game string.
  * @return The encoded string.
  */
-const char *GetGameStringPtr(uint id)
+const char *GetGameStringPtr(StringIndexInTab id)
 {
-	if (_current_data == nullptr || _current_data->cur_language == nullptr || id >= _current_data->cur_language->lines.size()) return GetStringPtr(STR_UNDEFINED);
+	if (_current_data == nullptr || _current_data->cur_language == nullptr || id.base() >= _current_data->cur_language->lines.size()) return GetStringPtr(STR_UNDEFINED);
-	return _current_data->cur_language->lines[id].c_str();
+	return _current_data->cur_language->lines[id.base()].c_str();
 }
 
 /**
@@ -326,13 +326,13 @@ const char *GetGameStringPtr(uint id)
  * @param id The ID of the game string.
  * @return The string parameters.
  */
-const StringParams &GetGameStringParams(uint id)
+const StringParams &GetGameStringParams(StringIndexInTab id)
 {
 	/* An empty result for STR_UNDEFINED. */
 	static StringParams empty;
 
-	if (id >= _current_data->string_params.size()) return empty;
+	if (id.base() >= _current_data->string_params.size()) return empty;
-	return _current_data->string_params[id];
+	return _current_data->string_params[id.base()];
 }
 
 /**
@@ -340,13 +340,13 @@ const StringParams &GetGameStringParams(uint id)
  * @param id The ID of the game string.
  * @return The name of the string.
  */
-const std::string &GetGameStringName(uint id)
+const std::string &GetGameStringName(StringIndexInTab id)
 {
 	/* The name for STR_UNDEFINED. */
 	static const std::string undefined = "STR_UNDEFINED";
 
-	if (id >= _current_data->string_names.size()) return undefined;
+	if (id.base() >= _current_data->string_names.size()) return undefined;
-	return _current_data->string_names[id];
+	return _current_data->string_names[id.base()];
 }
 
 /**

src/game/game_text.hpp

@@ -10,6 +10,8 @@
 #ifndef GAME_TEXT_HPP
 #define GAME_TEXT_HPP
 
+#include "../strings_type.h"
+
 struct StringParam {
 	enum ParamType {
 		UNUSED,
@@ -27,9 +29,9 @@ struct StringParam {
 using StringParams = std::vector<StringParam>;
 using StringParamsList = std::vector<StringParams>;
 
-const char *GetGameStringPtr(uint id);
+const char *GetGameStringPtr(StringIndexInTab id);
-const StringParams &GetGameStringParams(uint id);
+const StringParams &GetGameStringParams(StringIndexInTab id);
-const std::string &GetGameStringName(uint id);
+const std::string &GetGameStringName(StringIndexInTab id);
 void RegisterGameTranslation(class Squirrel *engine);
 void ReconsiderGameScriptLanguage();
 

src/newgrf_text.cpp

@@ -571,7 +571,7 @@ StringID AddGRFString(uint32_t grfid, GRFStringID stringid, uint8_t langid_to_ad
 		it->stringid   = stringid;
 		it->def_string = def_string;
 	}
-	uint id = static_cast<uint>(it - std::begin(_grf_text));
+	StringIndexInTab id(it - std::begin(_grf_text));
 
 	std::string newtext = TranslateTTDPatchCodes(grfid, langid_to_add, allow_newlines, text_to_add);
 	AddGRFTextToList(it->textholder, langid_to_add, newtext);
@@ -588,7 +588,7 @@ StringID GetGRFStringID(uint32_t grfid, GRFStringID stringid)
 {
 	auto it = std::ranges::find_if(_grf_text, [&grfid, &stringid](const GRFTextEntry &grf_text) { return grf_text.grfid == grfid && grf_text.stringid == stringid; });
 	if (it != std::end(_grf_text)) {
-		uint id = static_cast<uint>(it - std::begin(_grf_text));
+		StringIndexInTab id(it - std::begin(_grf_text));
 		return MakeStringID(TEXT_TAB_NEWGRF_START, id);
 	}
 
@@ -636,16 +636,16 @@ const char *GetGRFStringFromGRFText(const GRFTextWrapper &text)
 /**
  * Get a C-string from a stringid set by a newgrf.
  */
-const char *GetGRFStringPtr(uint32_t stringid)
+const char *GetGRFStringPtr(StringIndexInTab stringid)
 {
-	assert(stringid < _grf_text.size());
+	assert(stringid.base() < _grf_text.size());
-	assert(_grf_text[stringid].grfid != 0);
+	assert(_grf_text[stringid.base()].grfid != 0);
 
-	const char *str = GetGRFStringFromGRFText(_grf_text[stringid].textholder);
+	const char *str = GetGRFStringFromGRFText(_grf_text[stringid.base()].textholder);
 	if (str != nullptr) return str;
 
 	/* Use the default string ID if the fallback string isn't available */
-	return GetStringPtr(_grf_text[stringid].def_string);
+	return GetStringPtr(_grf_text[stringid.base()].def_string);
 }
 
 /**

src/newgrf_text.h

@@ -18,7 +18,7 @@ StringID AddGRFString(uint32_t grfid, GRFStringID stringid, uint8_t langid, bool
 StringID GetGRFStringID(uint32_t grfid, GRFStringID stringid);
 const char *GetGRFStringFromGRFText(const GRFTextList &text_list);
 const char *GetGRFStringFromGRFText(const GRFTextWrapper &text);
-const char *GetGRFStringPtr(uint32_t stringid);
+const char *GetGRFStringPtr(StringIndexInTab stringid);
 void CleanUpStrings();
 void SetCurrentGrfLangID(uint8_t language_id);
 std::string TranslateTTDPatchCodes(uint32_t grfid, uint8_t language_id, bool allow_newlines, std::string_view str, StringControlCode byte80 = SCC_NEWGRF_PRINT_WORD_STRING_ID);

src/script/api/script_error.cpp

@@ -30,7 +30,7 @@ ScriptError::ScriptErrorMapString ScriptError::error_map_string = ScriptError::S
 
 /* static */ ScriptErrorType ScriptError::StringToError(StringID internal_string_id)
 {
-	uint index = GetStringIndex(internal_string_id);
+	StringIndexInTab index = GetStringIndex(internal_string_id);
 	switch (GetStringTab(internal_string_id)) {
 		case TEXT_TAB_NEWGRF_START:
 		case TEXT_TAB_GAMESCRIPT_START:

src/script/api/script_text.cpp

@@ -33,7 +33,7 @@ ScriptText::ScriptText(HSQUIRRELVM vm)
 	if (SQ_FAILED(sq_getinteger(vm, 2, &sqstring))) {
 		throw sq_throwerror(vm, "First argument must be a valid StringID");
 	}
-	this->string = sqstring;
+	this->string = StringIndexInTab(sqstring);
 
 	/* The rest of the parameters must be arguments. */
 	for (int i = 0; i < nparam - 1; i++) {
@@ -185,7 +185,7 @@ void ScriptText::_FillParamList(ParamList &params, ScriptTextList &seen_texts)
 		static Param dummy = 0;
 		int nb_extra = SCRIPT_TEXT_MAX_PARAMETERS - (int)params.size();
 		for (int i = 0; i < nb_extra; i++)
-			params.emplace_back(-1, i, &dummy);
+			params.emplace_back(StringIndexInTab(-1), i, &dummy);
 	}
 }
 

src/script/api/script_text.hpp

@@ -132,13 +132,13 @@ private:
 	using Param = std::variant<SQInteger, std::string, ScriptTextRef>;
 
 	struct ParamCheck {
-		StringID owner;
+		StringIndexInTab owner;
 		int idx;
 		Param *param;
 		bool used = false;
 		const char *cmd = nullptr;
 
-		ParamCheck(StringID owner, int idx, Param *param) : owner(owner), idx(idx), param(param) {}
+		ParamCheck(StringIndexInTab owner, int idx, Param *param) : owner(owner), idx(idx), param(param) {}
 
 		void Encode(std::back_insert_iterator<std::string> &output, const char *cmd);
 	};
@@ -146,7 +146,7 @@ private:
 	using ParamList = std::vector<ParamCheck>;
 	using ParamSpan = std::span<ParamCheck>;
 
-	StringID string;
+	StringIndexInTab string;
 	std::array<Param, SCRIPT_TEXT_MAX_PARAMETERS> param = {};
 	int paramc = 0;
 

src/strings.cpp

@@ -239,7 +239,7 @@ const char *GetStringPtr(StringID string)
 		case TEXT_TAB_OLD_NEWGRF: NOT_REACHED();
 		case TEXT_TAB_NEWGRF_START: return GetGRFStringPtr(GetStringIndex(string));
 		default: {
-			const uint offset = _langpack.langtab_start[GetStringTab(string)] + GetStringIndex(string);
+			const size_t offset = _langpack.langtab_start[GetStringTab(string)] + GetStringIndex(string).base();
 			if (offset < _langpack.offsets.size()) return _langpack.offsets[offset];
 			return nullptr;
 		}
@@ -261,14 +261,14 @@ void GetStringWithArgs(StringBuilder &builder, StringID string, StringParameters
 		return;
 	}
 
-	uint index = GetStringIndex(string);
+	StringIndexInTab index = GetStringIndex(string);
 	StringTab tab = GetStringTab(string);
 
 	switch (tab) {
 		case TEXT_TAB_TOWN:
 			if (index >= 0xC0 && !game_script) {
 				try {
-					GetSpecialTownNameString(builder, index - 0xC0, args.GetNextParameter<uint32_t>());
+					GetSpecialTownNameString(builder, index.base() - 0xC0, args.GetNextParameter<uint32_t>());
 				} catch (const std::runtime_error &e) {
 					Debug(misc, 0, "GetStringWithArgs: {}", e.what());
 					builder += "(invalid string parameter)";
@@ -280,7 +280,7 @@ void GetStringWithArgs(StringBuilder &builder, StringID string, StringParameters
 		case TEXT_TAB_SPECIAL:
 			if (index >= 0xE4 && !game_script) {
 				try {
-					GetSpecialNameString(builder, index - 0xE4, args);
+					GetSpecialNameString(builder, index.base() - 0xE4, args);
 				} catch (const std::runtime_error &e) {
 					Debug(misc, 0, "GetStringWithArgs: {}", e.what());
 					builder += "(invalid string parameter)";
@@ -987,7 +987,7 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 					ArrayStringParameters<20> sub_args;
 
 					char *p;
-					uint32_t stringid = std::strtoul(str, &p, 16);
+					StringIndexInTab stringid(std::strtoul(str, &p, 16));
 					if (*p != ':' && *p != '\0') {
 						while (*p != '\0') p++;
 						str = p;
@@ -1048,7 +1048,7 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 									builder += "(invalid sub-StringID)";
 									break;
 								}
-								param = MakeStringID(TEXT_TAB_GAMESCRIPT_START, param);
+								param = MakeStringID(TEXT_TAB_GAMESCRIPT_START, StringIndexInTab(param));
 							}
 
 							sub_args.SetParam(i++, param);

src/strings_func.h

@@ -35,18 +35,18 @@ inline StringTab GetStringTab(StringID str)
  * @param str String identifier
  * @return StringIndex from \a str
  */
-inline uint GetStringIndex(StringID str)
+inline StringIndexInTab GetStringIndex(StringID str)
 {
-	return str - (GetStringTab(str) << TAB_SIZE_BITS);
+	return StringIndexInTab{str - (GetStringTab(str) << TAB_SIZE_BITS)};
 }
 
 /**
  * Create a StringID
  * @param tab StringTab
- * @param index StringIndex
+ * @param index Index of the string within the given tab.
  * @return StringID composed from \a tab and \a index
  */
-inline StringID MakeStringID(StringTab tab, uint index)
+inline StringID MakeStringID(StringTab tab, StringIndexInTab index)
 {
 	if (tab == TEXT_TAB_NEWGRF_START) {
 		assert(index < TAB_SIZE_NEWGRF);
@@ -56,7 +56,7 @@ inline StringID MakeStringID(StringTab tab, uint index)
 		assert(tab < TEXT_TAB_END);
 		assert(index < TAB_SIZE);
 	}
-	return (tab << TAB_SIZE_BITS) + index;
+	return (tab << TAB_SIZE_BITS) + index.base();
 }
 
 std::string GetString(StringID string);

src/strings_type.h

@@ -10,6 +10,8 @@
 #ifndef STRINGS_TYPE_H
 #define STRINGS_TYPE_H
 
+#include "core/strong_typedef_type.hpp"
+
 /**
  * Numeric value that represents a string, independent of the selected language.
  */
@@ -40,6 +42,9 @@ enum StringTab {
 	TEXT_TAB_NEWGRF_START     = 64, ///< Start of NewGRF supplied strings.
 };
 
+/** The index/offset of a string within a #StringTab. */
+using StringIndexInTab = StrongType::Typedef<uint32_t, struct StringIndexInTabTag, StrongType::Compare, StrongType::Integer>;
+
 /** Number of bits for the StringIndex within a StringTab */
 static const uint TAB_SIZE_BITS       = 11;
 /** Number of strings per StringTab */