Replace fmt with utils/str_cat in a few places

`fmt::format_to` is overkill for our simple formatting needs.

Source/CMakeLists.txt

@@ -797,8 +797,8 @@ if(USE_SDL1)
     utils/sdl2_to_1_2_backports.cpp
   )
   target_link_dependencies(libdevilutionx_sdl2_to_1_2_backports PRIVATE
+    libdevilutionx_strings
     libdevilutionx_utils_console
-    fmt::fmt
   )
   target_link_libraries(DevilutionX::SDL INTERFACE
     libdevilutionx_sdl2_to_1_2_backports

Source/capture.cpp

@@ -11,7 +11,6 @@
 
 #include <SDL.h>
 #include <expected.hpp>
-#include <fmt/format.h>
 
 #define DEVILUTIONX_SCREENSHOT_FORMAT_PCX 0
 #define DEVILUTIONX_SCREENSHOT_FORMAT_PNG 1
@@ -46,8 +45,9 @@ SDL_RWops *CaptureFile(std::string *dstPath)
 	const std::time_t tt = std::time(nullptr);
 	const std::tm *tm = std::localtime(&tt);
 	const std::string filename = tm != nullptr
-	    ? fmt::format("Screenshot from {:04}-{:02}-{:02} {:02}-{:02}-{:02}",
+	    ? StrCat("Screenshot from ",
-	          tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec)
+	          LeftPad(tm->tm_year + 1900, 4, '0'), "-", LeftPad(tm->tm_mon + 1, 2, '0'), "-", LeftPad(tm->tm_mday, 2, '0'), "-",
+	          LeftPad(tm->tm_hour, 2, '0'), "-", LeftPad(tm->tm_min, 2, '0'), "-", LeftPad(tm->tm_sec, 2, '0'))
 	    : "Screenshot";
 	*dstPath = StrCat(paths::PrefPath(), filename, ext);
 	int i = 0;

Source/engine/assets.cpp

@@ -367,7 +367,7 @@ std::vector<std::string> GetMPQSearchPaths()
 
 		std::string message;
 		for (std::size_t i = 0; i < paths.size(); ++i) {
-			message.append(fmt::format("\n{:6d}. '{}'", i + 1, paths[i]));
+			message.append(StrCat("\n", LeftPad(i + 1, 6, ' '), ". '", paths[i], "'"));
 		}
 		LogVerbose("MPQ search paths:{}", message);
 	}

Source/engine/demomode.cpp

@@ -5,8 +5,6 @@
 #include <limits>
 #include <optional>
 
-#include <fmt/format.h>
-
 #ifdef USE_SDL1
 #include "utils/sdl2_to_1_2_backports.h"
 #endif
@@ -180,7 +178,7 @@ void ReadSettings(FILE *in, uint8_t version) // NOLINT(readability-identifier-le
 		DemoSettings = {};
 	}
 
-	std::string message = fmt::format("⚙️\n{}={}x{}", _("Resolution"), DemoGraphicsWidth, DemoGraphicsHeight);
+	std::string message = StrCat("⚙️\n", _("Resolution"), "=", DemoGraphicsWidth, "x", DemoGraphicsHeight);
 	for (const auto &[key, value] : std::initializer_list<std::pair<std::string_view, bool>> {
 	         { _("Run in Town"), DemoSettings.runInTown },
 	         { _("Theo Quest"), DemoSettings.theoQuest },
@@ -199,7 +197,7 @@ void ReadSettings(FILE *in, uint8_t version) // NOLINT(readability-identifier-le
 	         { _("Show Item Labels"), DemoSettings.showItemLabels },
 	         { _("Auto Refill Belt"), DemoSettings.autoRefillBelt },
 	         { _("Disable Crippling Shrines"), DemoSettings.disableCripplingShrines } }) {
-		fmt::format_to(std::back_inserter(message), "\n{}={:d}", key, value);
+		StrAppend(message, "\n", key, "=", value ? "1" : "0");
 	}
 	for (const auto &[key, value] : std::initializer_list<std::pair<std::string_view, uint8_t>> {
 	         { _("Heal Potion Pickup"), DemoSettings.numHealPotionPickup },
@@ -208,7 +206,7 @@ void ReadSettings(FILE *in, uint8_t version) // NOLINT(readability-identifier-le
 	         { _("Full Mana Potion Pickup"), DemoSettings.numFullManaPotionPickup },
 	         { _("Rejuvenation Potion Pickup"), DemoSettings.numRejuPotionPickup },
 	         { _("Full Rejuvenation Potion Pickup"), DemoSettings.numFullRejuPotionPickup } }) {
-		fmt::format_to(std::back_inserter(message), "\n{}={}", key, value);
+		StrAppend(message, "\n", key, "=", static_cast<int>(value));
 	}
 	Log("{}", message);
 }
@@ -776,8 +774,8 @@ void RecordMessage(const SDL_Event &event, uint16_t modState)
 		    || event.wheel.x > std::numeric_limits<int16_t>::max()
 		    || event.wheel.y < std::numeric_limits<int16_t>::min()
 		    || event.wheel.y > std::numeric_limits<int16_t>::max()) {
-			app_fatal(fmt::format("Mouse wheel event x/y out of int16_t range. x={} y={}",
+			app_fatal(StrCat("Mouse wheel event x/y out of int16_t range. x=",
-			    event.wheel.x, event.wheel.y));
+			    event.wheel.x, " y=", event.wheel.y));
 		}
 		WriteLE16(DemoRecording, event.wheel.x);
 		WriteLE16(DemoRecording, event.wheel.y);

Source/engine/palette.cpp

@@ -11,8 +11,6 @@
 #include <cstring>
 #include <span>
 
-#include <fmt/core.h>
-
 #include "engine/backbuffer_state.hpp"
 #include "engine/demomode.h"
 #include "engine/dx.h"
@@ -24,6 +22,7 @@
 #include "utils/display.h"
 #include "utils/palette_blending.hpp"
 #include "utils/sdl_compat.h"
+#include "utils/str_cat.hpp"
 
 namespace devilution {
 
@@ -214,9 +213,12 @@ void LoadRndLvlPal(dungeon_type l)
 		if (!*GetOptions().Graphics.alternateNestArt) {
 			rv++;
 		}
-		*fmt::format_to(szFileName, R"(nlevels\l{0}data\l{0}base{1}.pal)", 6, rv) = '\0';
+		*BufCopy(szFileName, R"(nlevels\l6data\l6base)", rv, ".pal") = '\0';
 	} else {
-		*fmt::format_to(szFileName, R"(levels\l{0}data\l{0}_{1}.pal)", static_cast<int>(l), rv) = '\0';
+		char nbuf[3];
+		const char *end = BufCopy(nbuf, static_cast<int>(l));
+		const std::string_view n = std::string_view(nbuf, end - nbuf);
+		*BufCopy(szFileName, "levels\\l", n, "data\\l", n, "_", rv, ".pal") = '\0';
 	}
 	LoadPaletteAndInitBlending(szFileName);
 }

Source/items.cpp

@@ -3573,7 +3573,7 @@ void CornerstoneSave()
 		PackItem(id, CornerStone.item, (CornerStone.item.dwBuff & CF_HELLFIRE) != 0);
 		const auto *buffer = reinterpret_cast<uint8_t *>(&id);
 		for (size_t i = 0; i < sizeof(ItemPack); i++) {
-			fmt::format_to(&GetOptions().Hellfire.szItem[i * 2], "{:02X}", buffer[i]);
+			BufCopy(&GetOptions().Hellfire.szItem[i * 2], AsHexPad2(buffer[i], /*uppercase=*/true));
 		}
 		GetOptions().Hellfire.szItem[sizeof(GetOptions().Hellfire.szItem) - 1] = '\0';
 	} else {

Source/loadsave.cpp

@@ -15,7 +15,6 @@
 #include <SDL.h>
 #include <ankerl/unordered_dense.h>
 #include <expected.hpp>
-#include <fmt/core.h>
 
 #include "automap.h"
 #include "codec.h"
@@ -1049,7 +1048,7 @@ void GetLevelNames(std::string_view prefix, char *out)
 		suf = 'l';
 		num = currlevel;
 	}
-	*fmt::format_to(out, "{}{}{:02d}", prefix, suf, num) = '\0';
+	*BufCopy(out, prefix, std::string_view(&suf, 1), LeftPad(num, 2, '0')) = '\0';
 }
 
 void GetTempLevelNames(char *szTemp)

Source/pfile.cpp

@@ -11,7 +11,6 @@
 
 #include <ankerl/unordered_dense.h>
 #include <expected.hpp>
-#include <fmt/core.h>
 
 #include "codec.h"
 #include "engine/load_file.hpp"
@@ -92,7 +91,7 @@ bool GetSaveNames(uint8_t index, std::string_view prefix, char *out)
 		return false;
 	}
 
-	*fmt::format_to(out, "{}{}{:02d}", prefix, suf, index) = '\0';
+	*BufCopy(out, prefix, std::string_view(&suf, 1), LeftPad(index, 2, '0')) = '\0';
 	return true;
 }
 

Source/player.cpp

@@ -1516,6 +1516,11 @@ uint16_t GetPlayerSpriteWidth(HeroClass cls, player_graphic graphic, PlayerWeapo
 	app_fatal("Invalid player_graphic");
 }
 
+void GetPlayerGraphicsPath(std::string_view path, std::string_view prefix, std::string_view type, char out[256])
+{
+	*BufCopy(out, "plrgfx\\", path, "\\", prefix, "\\", prefix, type) = '\0';
+}
+
 } // namespace
 
 void Player::CalcScrolls()
@@ -2054,11 +2059,7 @@ ClxSprite GetPlayerPortraitSprite(Player &player)
 	const PlayerSpriteData &spriteData = GetPlayerSpriteDataForClass(cls);
 	const char *path = spriteData.classPath.c_str();
 
-	const char *szCel;
+	std::string_view szCel = inDungeon ? "as" : "st";
-	if (!inDungeon)
-		szCel = "st";
-	else
-		szCel = "as";
 
 	player_graphic graphic = player_graphic::Stand;
 	if (player._pHitPoints <= 0) {
@@ -2068,9 +2069,9 @@ ClxSprite GetPlayerPortraitSprite(Player &player)
 		}
 	}
 
-	char prefix[3] = { spriteData.classChar, ArmourChar[player._pgfxnum >> 4], WepChar[static_cast<std::size_t>(animWeaponId)] };
+	const char prefixBuf[3] = { spriteData.classChar, ArmourChar[player._pgfxnum >> 4], WepChar[static_cast<std::size_t>(animWeaponId)] };
 	char pszName[256];
-	*fmt::format_to(pszName, R"(plrgfx\{0}\{1}\{1}{2})", path, std::string_view(prefix, 3), szCel) = 0;
+	GetPlayerGraphicsPath(path, std::string_view(prefixBuf, 3), szCel, pszName);
 
 	const std::string spritePath { pszName };
 	// Check to see if the sprite has updated.
@@ -2110,7 +2111,7 @@ void LoadPlrGFX(Player &player, player_graphic graphic)
 	const PlayerSpriteData &spriteData = GetPlayerSpriteDataForClass(cls);
 	const char *path = spriteData.classPath.c_str();
 
-	const char *szCel;
+	std::string_view szCel;
 	switch (graphic) {
 	case player_graphic::Stand:
 		szCel = "as";
@@ -2157,9 +2158,9 @@ void LoadPlrGFX(Player &player, player_graphic graphic)
 		app_fatal("PLR:2");
 	}
 
-	char prefix[3] = { spriteData.classChar, ArmourChar[player._pgfxnum >> 4], WepChar[static_cast<std::size_t>(animWeaponId)] };
+	const char prefixBuf[3] = { spriteData.classChar, ArmourChar[player._pgfxnum >> 4], WepChar[static_cast<std::size_t>(animWeaponId)] };
 	char pszName[256];
-	*fmt::format_to(pszName, R"(plrgfx\{0}\{1}\{1}{2})", path, std::string_view(prefix, 3), szCel) = 0;
+	GetPlayerGraphicsPath(path, std::string_view(prefixBuf, 3), szCel, pszName);
 	const uint16_t animationWidth = GetPlayerSpriteWidth(cls, graphic, animWeaponId);
 	animationData.sprites = LoadCl2Sheet(pszName, animationWidth);
 	std::optional<std::array<uint8_t, 256>> graphicTRN = GetPlayerGraphicTRN(pszName);

Source/qol/chatlog.cpp

@@ -24,6 +24,7 @@
 #include "minitext.h"
 #include "stores.h"
 #include "utils/language.h"
+#include "utils/str_cat.hpp"
 
 namespace devilution {
 
@@ -119,8 +120,9 @@ void AddMessageToChatLog(std::string_view message, Player *player, UiFlags flags
 	MessageCounter++;
 	const time_t timeResult = time(nullptr);
 	const std::tm *localtimeResult = localtime(&timeResult);
-	std::string timestamp = localtimeResult != nullptr ? fmt::format("[#{:d}] {:02}:{:02}:{:02}", MessageCounter, localtimeResult->tm_hour, localtimeResult->tm_min, localtimeResult->tm_sec)
+	std::string timestamp = localtimeResult != nullptr
-	                                                   : fmt::format("[#{:d}] ", MessageCounter);
+	    ? StrCat("[#", MessageCounter, "] ", LeftPad(localtimeResult->tm_hour, 2, '0'), ":", LeftPad(localtimeResult->tm_min, 2, '0'), ":", LeftPad(localtimeResult->tm_sec, 2, '0'))
+	    : StrCat("[#", MessageCounter, "] ");
 	const size_t oldSize = ChatLogLines.size();
 	if (player == nullptr) {
 		ChatLogLines.emplace_back(MultiColoredText { "{0} {1}", { { timestamp, UiFlags::ColorRed }, { std::string(message), flags } } });
@@ -172,7 +174,8 @@ void DrawChatLog(const Surface &out)
 	const time_t timeResult = time(nullptr);
 	const std::tm *localtimeResult = localtime(&timeResult);
 	if (localtimeResult != nullptr) {
-		const std::string timestamp = fmt::format("{:02}:{:02}:{:02}", localtimeResult->tm_hour, localtimeResult->tm_min, localtimeResult->tm_sec);
+		const std::string timestamp = StrCat(
+		    LeftPad(localtimeResult->tm_hour, 2, '0'), ":", LeftPad(localtimeResult->tm_min, 2, '0'), ":", LeftPad(localtimeResult->tm_sec, 2, '0'));
 		DrawString(out, timestamp, { { sx, sy + PaddingTop + blankLineHeight }, { ContentTextWidth, lineHeight } },
 		    { .flags = UiFlags::ColorWhitegold });
 	}

Source/utils/sdl2_to_1_2_backports.cpp

@@ -15,9 +15,8 @@
 #include <windows.h>
 #endif
 
-#include <fmt/format.h>
-
 #include "utils/console.h"
+#include "utils/str_cat.hpp"
 
 #define DEFAULT_PRIORITY SDL_LOG_PRIORITY_CRITICAL
 #define DEFAULT_ASSERT_PRIORITY SDL_LOG_PRIORITY_WARN
@@ -919,9 +918,9 @@ extern "C" char *SDL_GetPrefPath(const char *org, const char *app)
 	}
 
 	if (*org) {
-		*fmt::format_to_n(retval, len - 1, "{}{}{}/{}", envr, append, org, app).out = '\0';
+		*devilution::BufCopy(retval, envr, append, org, "/", app) = '\0';
 	} else {
-		*fmt::format_to_n(retval, len - 1, "{}{}{}", envr, append, app).out = '\0';
+		*devilution::BufCopy(retval, envr, append, app) = '\0';
 	}
 
 	for (ptr = retval + 1; *ptr; ptr++) {

Source/utils/str_cat.cpp

@@ -9,6 +9,7 @@ namespace devilution {
 namespace {
 
 [[nodiscard]] char HexDigit(uint8_t v) { return "0123456789abcdef"[v]; }
+[[nodiscard]] char HexDigitUpper(uint8_t v) { return "0123456789ABCDEF"[v]; }
 
 } // namespace
 
@@ -26,8 +27,13 @@ char *BufCopy(char *out, unsigned long long value)
 }
 char *BufCopy(char *out, AsHexU8Pad2 value)
 {
-	*out++ = HexDigit(value.value >> 4);
+	if (value.uppercase) {
-	*out++ = HexDigit(value.value & 0xf);
+		*out++ = HexDigitUpper(value.value >> 4);
+		*out++ = HexDigitUpper(value.value & 0xf);
+	} else {
+		*out++ = HexDigit(value.value >> 4);
+		*out++ = HexDigit(value.value & 0xf);
+	}
 	return out;
 }
 char *BufCopy(char *out, AsHexU16Pad2 value)
@@ -36,7 +42,7 @@ char *BufCopy(char *out, AsHexU16Pad2 value)
 		if (value.value > 0xfff) {
 			out = BufCopy(out, AsHexU8Pad2 { static_cast<uint8_t>(value.value >> 8) });
 		} else {
-			*out++ = HexDigit(value.value >> 8);
+			*out++ = value.uppercase ? HexDigitUpper(value.value >> 8) : HexDigit(value.value >> 8);
 		}
 	}
 	return BufCopy(out, AsHexU8Pad2 { static_cast<uint8_t>(value.value & 0xff) });

Source/utils/str_cat.hpp

@@ -10,21 +10,42 @@ namespace devilution {
 
 struct AsHexU8Pad2 {
 	uint8_t value;
+	bool uppercase = false;
 };
 
 struct AsHexU16Pad2 {
 	uint16_t value;
+	bool uppercase = false;
+};
+
+/** @brief Maximum number of digits for a value of type T.
+ * If T is signed, also accounts for a potential '-'.
+ */
+template <typename T>
+constexpr size_t MaxNumDigits = (8 * sizeof(T) * 28 / 93) + 1 + (std::is_signed_v<T> ? 1 : 0);
+
+template <typename T>
+struct LeftPadT {
+	T value;
+	unsigned length;
+	char padChar;
 };
 
 /**
  * @brief Formats the value as a lowercase zero-padded hexadecimal with at least 2 hex digits (0-padded on the left).
  */
-constexpr AsHexU8Pad2 AsHexPad2(uint8_t value) { return { value }; }
+constexpr AsHexU8Pad2 AsHexPad2(uint8_t value, bool uppercase = false) { return { value, uppercase }; }
 
 /**
  * @brief Formats the value as a lowercase zero-padded hexadecimal with at least 2 hex digits (0-padded on the left).
  */
-constexpr AsHexU16Pad2 AsHexPad2(uint16_t value) { return { value }; }
+constexpr AsHexU16Pad2 AsHexPad2(uint16_t value, bool uppercase = false) { return { value, uppercase }; }
+
+/**
+ * @brief Left-pads the value to the specified length with the specified character.
+ */
+template <typename T>
+constexpr LeftPadT<T> LeftPad(T value, unsigned length, char padChar) { return { value, length, padChar }; }
 
 /**
  * @brief Writes the integer to the given buffer.
@@ -65,6 +86,19 @@ inline char *BufCopy(char *out, unsigned short value)
 char *BufCopy(char *out, AsHexU8Pad2 value);
 char *BufCopy(char *out, AsHexU16Pad2 value);
 
+template <typename T>
+char *BufCopy(char *out, LeftPadT<T> value)
+{
+	char buf[MaxNumDigits<T>];
+	const char *end = BufCopy(buf, value.value);
+	const std::string_view str = std::string_view(buf, end - buf);
+	for (size_t i = str.size(); i < value.length; ++i) {
+		*out++ = value.padChar;
+	}
+	std::memcpy(out, str.data(), str.size());
+	return out + str.size();
+}
+
 /**
  * @brief Appends the integer to the given string.
  */
@@ -102,6 +136,14 @@ inline void StrAppend(std::string &out, unsigned short value)
 void StrAppend(std::string &out, AsHexU8Pad2 value);
 void StrAppend(std::string &out, AsHexU16Pad2 value);
 
+template <typename T>
+void StrAppend(std::string &out, LeftPadT<T> value)
+{
+	char buf[MaxNumDigits<T>];
+	const auto len = static_cast<size_t>(BufCopy(buf, value) - buf);
+	out.append(buf, len);
+}
+
 /**
  * @brief Copies the given std::string_view to the given buffer.
  */

test/str_cat_test.cpp

@@ -1,3 +1,5 @@
+#include <cstdint>
+
 #include <gtest/gtest.h>
 
 #include "utils/str_cat.hpp"
@@ -10,6 +12,11 @@ TEST(StrCatTest, StrCatBasicTest)
 	EXPECT_EQ(StrCat("a", "b", "c", 5), "abc5");
 }
 
+TEST(StrCatTest, LeftPadTest)
+{
+	EXPECT_EQ(StrCat(LeftPad(static_cast<uint8_t>(5), 2, '0')), "05");
+}
+
 TEST(StrCatTest, BufCopyBasicTest)
 {
 	char buf[5];