diff --git a/include/kabufuda/Constants.hpp b/include/kabufuda/Constants.hpp
index 998a1fd..e9ab761 100644
--- a/include/kabufuda/Constants.hpp
+++ b/include/kabufuda/Constants.hpp
@@ -59,10 +59,10 @@ enum class ECardSize : uint16_t {
   Card2043Mb = 0x80
 };
 
-static constexpr uint32_t BannerWidth = 96;
-static constexpr uint32_t BannerHeight = 64;
-static constexpr uint32_t IconWidth = 32;
-static constexpr uint32_t IconHeight = 32;
+constexpr uint32_t BannerWidth = 96;
+constexpr uint32_t BannerHeight = 64;
+constexpr uint32_t IconWidth = 32;
+constexpr uint32_t IconHeight = 32;
 
 /**
  * @brief The EEncoding enum
diff --git a/include/kabufuda/Util.hpp b/include/kabufuda/Util.hpp
index eb3d884..a7aebd8 100644
--- a/include/kabufuda/Util.hpp
+++ b/include/kabufuda/Util.hpp
@@ -75,7 +75,7 @@ namespace kabufuda {
 
 /* Type-sensitive byte swappers */
 template <typename T>
-static inline T bswap16(T val) {
+constexpr T bswap16(T val) {
 #if __GNUC__
   return __builtin_bswap16(val);
 #elif _WIN32
@@ -86,7 +86,7 @@ static inline T bswap16(T val) {
 }
 
 template <typename T>
-static inline T bswap32(T val) {
+constexpr T bswap32(T val) {
 #if __GNUC__
   return __builtin_bswap32(val);
 #elif _WIN32
@@ -99,7 +99,7 @@ static inline T bswap32(T val) {
 }
 
 template <typename T>
-static inline T bswap64(T val) {
+constexpr T bswap64(T val) {
 #if __GNUC__
   return __builtin_bswap64(val);
 #elif _WIN32
@@ -113,18 +113,18 @@ static inline T bswap64(T val) {
 }
 
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-static inline int16_t SBig(int16_t val) { return bswap16(val); }
-static inline uint16_t SBig(uint16_t val) { return bswap16(val); }
-static inline int32_t SBig(int32_t val) { return bswap32(val); }
-static inline uint32_t SBig(uint32_t val) { return bswap32(val); }
-static inline int64_t SBig(int64_t val) { return bswap64(val); }
-static inline uint64_t SBig(uint64_t val) { return bswap64(val); }
-inline float SBig(float val) {
+constexpr int16_t SBig(int16_t val) { return bswap16(val); }
+constexpr uint16_t SBig(uint16_t val) { return bswap16(val); }
+constexpr int32_t SBig(int32_t val) { return bswap32(val); }
+constexpr uint32_t SBig(uint32_t val) { return bswap32(val); }
+constexpr int64_t SBig(int64_t val) { return bswap64(val); }
+constexpr uint64_t SBig(uint64_t val) { return bswap64(val); }
+constexpr float SBig(float val) {
   union { float f; int32_t i; } uval1 = {val};
   union { int32_t i; float f; } uval2 = {bswap32(uval1.i)};
   return uval2.f;
 }
-inline double SBig(double val) {
+constexpr double SBig(double val) {
   union { double f; int64_t i; } uval1 = {val};
   union { int64_t i; double f; } uval2 = {bswap64(uval1.i)};
   return uval2.f;
@@ -133,29 +133,29 @@ inline double SBig(double val) {
 #define SBIG(q) (((q)&0x000000FF) << 24 | ((q)&0x0000FF00) << 8 | ((q)&0x00FF0000) >> 8 | ((q)&0xFF000000) >> 24)
 #endif
 
-static inline int16_t SLittle(int16_t val) { return val; }
-static inline uint16_t SLittle(uint16_t val) { return val; }
-static inline int32_t SLittle(int32_t val) { return val; }
-static inline uint32_t SLittle(uint32_t val) { return val; }
-static inline int64_t SLittle(int64_t val) { return val; }
-static inline uint64_t SLittle(uint64_t val) { return val; }
-static inline float SLittle(float val) { return val; }
-static inline double SLittle(double val) { return val; }
+constexpr int16_t SLittle(int16_t val) { return val; }
+constexpr uint16_t SLittle(uint16_t val) { return val; }
+constexpr int32_t SLittle(int32_t val) { return val; }
+constexpr uint32_t SLittle(uint32_t val) { return val; }
+constexpr int64_t SLittle(int64_t val) { return val; }
+constexpr uint64_t SLittle(uint64_t val) { return val; }
+constexpr float SLittle(float val) { return val; }
+constexpr double SLittle(double val) { return val; }
 #ifndef SLITTLE
 #define SLITTLE(q) (q)
 #endif
 #else
-static inline int16_t SLittle(int16_t val) { return bswap16(val); }
-static inline uint16_t SLittle(uint16_t val) { return bswap16(val); }
-static inline int32_t SLittle(int32_t val) { return bswap32(val); }
-static inline uint32_t SLittle(uint32_t val) { return bswap32(val); }
-static inline int64_t SLittle(int64_t val) { return bswap64(val); }
-static inline uint64_t SLittle(uint64_t val) { return bswap64(val); }
-static inline float SLittle(float val) {
+constexpr int16_t SLittle(int16_t val) { return bswap16(val); }
+constexpr uint16_t SLittle(uint16_t val) { return bswap16(val); }
+constexpr int32_t SLittle(int32_t val) { return bswap32(val); }
+constexpr uint32_t SLittle(uint32_t val) { return bswap32(val); }
+constexpr int64_t SLittle(int64_t val) { return bswap64(val); }
+constexpr uint64_t SLittle(uint64_t val) { return bswap64(val); }
+constexpr float SLittle(float val) {
   int32_t ival = bswap32(*((int32_t*)(&val)));
   return *((float*)(&ival));
 }
-static inline double SLittle(double val) {
+constexpr double SLittle(double val) {
   int64_t ival = bswap64(*((int64_t*)(&val)));
   return *((double*)(&ival));
 }
@@ -163,14 +163,14 @@ static inline double SLittle(double val) {
 #define SLITTLE(q) (((q)&0x000000FF) << 24 | ((q)&0x0000FF00) << 8 | ((q)&0x00FF0000) >> 8 | ((q)&0xFF000000) >> 24)
 #endif
 
-static inline int16_t SBig(int16_t val) { return val; }
-static inline uint16_t SBig(uint16_t val) { return val; }
-static inline int32_t SBig(int32_t val) { return val; }
-static inline uint32_t SBig(uint32_t val) { return val; }
-static inline int64_t SBig(int64_t val) { return val; }
-static inline uint64_t SBig(uint64_t val) { return val; }
-static inline float SBig(float val) { return val; }
-static inline double SBig(double val) { return val; }
+constexpr int16_t SBig(int16_t val) { return val; }
+constexpr uint16_t SBig(uint16_t val) { return val; }
+constexpr int32_t SBig(int32_t val) { return val; }
+constexpr uint32_t SBig(uint32_t val) { return val; }
+constexpr int64_t SBig(int64_t val) { return val; }
+constexpr uint64_t SBig(uint64_t val) { return val; }
+constexpr float SBig(float val) { return val; }
+constexpr double SBig(double val) { return val; }
 #ifndef SBIG
 #define SBIG(q) (q)
 #endif
@@ -178,11 +178,11 @@ static inline double SBig(double val) { return val; }
 
 #if CARD_UCS2
 typedef wchar_t SystemChar;
-static inline size_t StrLen(const SystemChar* str) { return wcslen(str); }
+inline size_t StrLen(const SystemChar* str) { return wcslen(str); }
 typedef std::wstring SystemString;
 typedef std::wstring_view SystemStringView;
-static inline void ToLower(SystemString& str) { std::transform(str.begin(), str.end(), str.begin(), towlower); }
-static inline void ToUpper(SystemString& str) { std::transform(str.begin(), str.end(), str.begin(), towupper); }
+inline void ToLower(SystemString& str) { std::transform(str.begin(), str.end(), str.begin(), towlower); }
+inline void ToUpper(SystemString& str) { std::transform(str.begin(), str.end(), str.begin(), towupper); }
 class SystemUTF8Conv {
   std::string m_utf8;
 
@@ -211,11 +211,11 @@ inline std::wstring operator+(const std::wstring_view lhs, const SystemStringCon
 typedef struct _stat Sstat;
 #else
 typedef char SystemChar;
-static inline size_t StrLen(const SystemChar* str) { return strlen(str); }
+inline size_t StrLen(const SystemChar* str) { return strlen(str); }
 typedef std::string SystemString;
 typedef std::string_view SystemStringView;
-static inline void ToLower(SystemString& str) { std::transform(str.begin(), str.end(), str.begin(), tolower); }
-static inline void ToUpper(SystemString& str) { std::transform(str.begin(), str.end(), str.begin(), toupper); }
+inline void ToLower(SystemString& str) { std::transform(str.begin(), str.end(), str.begin(), tolower); }
+inline void ToUpper(SystemString& str) { std::transform(str.begin(), str.end(), str.begin(), toupper); }
 class SystemUTF8Conv {
   std::string_view m_utf8;
 
@@ -254,7 +254,7 @@ uint64_t getGCTime();
 #define S_ISDIR(m) (((m)&S_IFMT) == S_IFDIR)
 #endif
 
-static inline int Stat(const SystemChar* path, Sstat* statOut) {
+inline int Stat(const SystemChar* path, Sstat* statOut) {
 #if CARD_UCS2
   size_t pos;
   for (pos = 0; pos < 3 && path[pos] != L'\0'; ++pos) {}