Make struct Uppercase have constexpr methods

include/util.hpp

@@ -3,6 +3,9 @@
 #ifndef RGBDS_UTIL_HPP
 #define RGBDS_UTIL_HPP
 
+#include <algorithm>
+#include <ctype.h>
+#include <numeric>
 #include <stddef.h>
 #include <string>
 #include <unordered_map>
@@ -15,8 +18,19 @@ bool continuesIdentifier(int c);
 char const *printChar(int c);
 
 struct Uppercase {
-	size_t operator()(std::string const &str) const;
-	bool operator()(std::string const &str1, std::string const &str2) const;
+	// FNV-1a hash of an uppercased string
+	constexpr size_t operator()(std::string const &str) const {
+		return std::accumulate(RANGE(str), 0x811C9DC5, [](size_t hash, char c) {
+			return (hash ^ toupper(c)) * 16777619;
+		});
+	}
+
+	// Compare two strings without case-sensitivity (by converting to uppercase)
+	constexpr bool operator()(std::string const &str1, std::string const &str2) const {
+		return std::equal(RANGE(str1), RANGE(str2), [](char c1, char c2) {
+			return toupper(c1) == toupper(c2);
+		});
+	}
 };
 
 template<typename T>

src/util.cpp

@@ -2,8 +2,6 @@
 
 #include "util.hpp"
 
-#include <algorithm>
-#include <ctype.h>
 #include <stdint.h>
 #include <stdio.h>
 
@@ -61,19 +59,3 @@ char const *printChar(int c) {
 	buf[4] = '\0';
 	return buf;
 }
-
-// FNV-1a hash of an uppercased string
-size_t Uppercase::operator()(std::string const &str) const {
-	size_t hash = 0x811C9DC5;
-	for (char const &c : str) {
-		hash = (hash ^ toupper(c)) * 16777619;
-	}
-	return hash;
-}
-
-// Compare two strings without case-sensitivity (by converting to uppercase)
-bool Uppercase::operator()(std::string const &str1, std::string const &str2) const {
-	return std::equal(RANGE(str1), RANGE(str2), [](char c1, char c2) {
-		return toupper(c1) == toupper(c2);
-	});
-}