diff --git a/base32.cpp b/base32.cpp
index 6444caba..f474de07 100644
--- a/base32.cpp
+++ b/base32.cpp
@@ -26,16 +26,30 @@ void Base32Decoder::IsolatedInitialize(const NameValuePairs &parameters)
 		MakeParameters(Name::DecodingLookupArray(), GetDefaultDecodingLookupArray(), false)(Name::Log2Base(), 5, true)));
 }
 
+ANONYMOUS_NAMESPACE_BEGIN
+static const int s_array[256] = {
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, 24, 25, 26, 27, 28, 29, 30, 31, -1, -1, -1, -1, -1, -1,
+	-1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, -1, 11, 12, -1,
+	13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, -1, -1, -1, -1, -1,
+	-1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, -1, 11, 12, -1,
+	13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+NAMESPACE_END
+
+// Unrolled initialization, http://github.com/weidai11/cryptopp/issues/376
 const int *Base32Decoder::GetDefaultDecodingLookupArray()
 {
-	static volatile bool s_initialized = false;
-	static int s_array[256];
-
-	if (!s_initialized)
-	{
-		InitializeDecodingLookupArray(s_array, s_vecUpper, 32, true);
-		s_initialized = true;
-	}
 	return s_array;
 }
 
diff --git a/base64.cpp b/base64.cpp
index 9ba4226e..63f7b12b 100644
--- a/base64.cpp
+++ b/base64.cpp
@@ -53,17 +53,30 @@ void Base64Decoder::IsolatedInitialize(const NameValuePairs &parameters)
 		MakeParameters(Name::DecodingLookupArray(), GetDecodingLookupArray(), false)(Name::Log2Base(), 6, true)));
 }
 
+ANONYMOUS_NAMESPACE_BEGIN
+static const int s_stdArray[256] = {
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
+	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
+	-1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
+	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
+	-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+NAMESPACE_END
+
 const int *Base64Decoder::GetDecodingLookupArray()
 {
-	static volatile bool s_initialized = false;
-	static int s_array[256];
-
-	if (!s_initialized)
-	{
-		InitializeDecodingLookupArray(s_array, s_stdVec, 64, false);
-		s_initialized = true;
-	}
-	return s_array;
+	return s_stdArray;
 }
 
 void Base64URLDecoder::IsolatedInitialize(const NameValuePairs &parameters)
@@ -73,17 +86,31 @@ void Base64URLDecoder::IsolatedInitialize(const NameValuePairs &parameters)
 		MakeParameters(Name::DecodingLookupArray(), GetDecodingLookupArray(), false)(Name::Log2Base(), 6, true)));
 }
 
+ANONYMOUS_NAMESPACE_BEGIN
+static const int s_urlArray[256] = {
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1,
+	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
+	-1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
+	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63,
+	-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+NAMESPACE_END
+
+// Unrolled initialization, http://github.com/weidai11/cryptopp/issues/376
 const int *Base64URLDecoder::GetDecodingLookupArray()
 {
-	static volatile bool s_initialized = false;
-	static int s_array[256];
-
-	if (!s_initialized)
-	{
-		InitializeDecodingLookupArray(s_array, s_urlVec, 64, false);
-		s_initialized = true;
-	}
-	return s_array;
+	return s_urlArray;
 }
 
 NAMESPACE_END
diff --git a/hex.cpp b/hex.cpp
index 133c97e7..3871c4bd 100644
--- a/hex.cpp
+++ b/hex.cpp
@@ -29,16 +29,30 @@ void HexDecoder::IsolatedInitialize(const NameValuePairs &parameters)
 		MakeParameters(Name::DecodingLookupArray(), GetDefaultDecodingLookupArray(), false)(Name::Log2Base(), 4, true)));
 }
 
+ANONYMOUS_NAMESPACE_BEGIN
+static const int s_array[256] = {
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
+	-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+NAMESPACE_END
+
+// Unrolled initialization, http://github.com/weidai11/cryptopp/issues/376
 const int *HexDecoder::GetDefaultDecodingLookupArray()
 {
-	static volatile bool s_initialized = false;
-	static int s_array[256];
-
-	if (!s_initialized)
-	{
-		InitializeDecodingLookupArray(s_array, s_vecUpper, 16, true);
-		s_initialized = true;
-	}
 	return s_array;
 }
 
diff --git a/validat1.cpp b/validat1.cpp
index 0e3baf92..06c8113d 100644
--- a/validat1.cpp
+++ b/validat1.cpp
@@ -2430,33 +2430,44 @@ bool ValidateBaseCode()
 	byte data[255];
 	for (unsigned int i=0; i<255; i++)
 		data[i] = byte(i);
-	static const char hexEncoded[] =
-"000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F2021222324252627"
-"28292A2B2C2D2E2F303132333435363738393A3B3C3D3E3F404142434445464748494A4B4C4D4E4F"
-"505152535455565758595A5B5C5D5E5F606162636465666768696A6B6C6D6E6F7071727374757677"
-"78797A7B7C7D7E7F808182838485868788898A8B8C8D8E8F909192939495969798999A9B9C9D9E9F"
-"A0A1A2A3A4A5A6A7A8A9AAABACADAEAFB0B1B2B3B4B5B6B7B8B9BABBBCBDBEBFC0C1C2C3C4C5C6C7"
-"C8C9CACBCCCDCECFD0D1D2D3D4D5D6D7D8D9DADBDCDDDEDFE0E1E2E3E4E5E6E7E8E9EAEBECEDEEEF"
-"F0F1F2F3F4F5F6F7F8F9FAFBFCFDFE";
-	static const char base32Encoded[] =
-"AAASEA2EAWDAQCAJBIFS2DIQB6IBCESVCSKTNF22DEPBYHA7D2RUAIJCENUCKJTHFAWUWK3NFWZC8NBT"
-"GI3VIPJYG66DUQT5HS8V6R4AIFBEGTCFI3DWSUKKJPGE4VURKBIXEW4WKXMFQYC3MJPX2ZK8M7SGC2VD"
-"NTUYN35IPFXGY5DPP3ZZA6MUQP4HK7VZRB6ZW856RX9H9AEBSKB2JBNGS8EIVCWMTUG27D6SUGJJHFEX"
-"U4M3TGN4VQQJ5HW9WCS4FI7EWYVKRKFJXKX43MPQX82MDNXVYU45PP72ZG7MZRF7Z496BSQC2RCNMTYH"
-"3DE6XU8N3ZHN9WGT4MJ7JXQY49NPVYY55VQ77Z9A6HTQH3HF65V8T4RK7RYQ55ZR8D29F69W8Z5RR8H3"
-"9M7939R8";
-	const char *base64AndHexEncoded =
-"41414543417751464267634943516F4C4441304F4478415245684D554652595847426B6147787764"
-"486838674953496A4A43556D4A7967704B6973734C5334764D4445794D7A51310A4E6A63344F546F"
-"375044302B50304242516B4E4552555A4853456C4B5330784E546B395155564A5456465657563168"
-"5A576C746358563566594746695932526C5A6D646F615770720A6247317562334278636E4E306458"
-"5A3365486C3665337839666E2B4167594B44684957476834694A696F754D6A5936506B4A47536B35"
-"53566C7065596D5A71626E4A32656E3643680A6F714F6B7061616E714B6D717136797472712B7773"
-"624B7A744C573274376935757275387662362F774D484377385446787366497963724C7A4D334F7A"
-"39445230745055316462580A324E6E6132397A6433742F6734654C6A354F586D352B6A7036757673"
-"3765377638504879382F5431397666342B6672372F50332B0A";
 
-	std::cout << "\nBase64, base32 and hex coding validation suite running...\n\n";
+	static const char hexEncoded[] =
+		"000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F2021222324252627"
+		"28292A2B2C2D2E2F303132333435363738393A3B3C3D3E3F404142434445464748494A4B4C4D4E4F"
+		"505152535455565758595A5B5C5D5E5F606162636465666768696A6B6C6D6E6F7071727374757677"
+		"78797A7B7C7D7E7F808182838485868788898A8B8C8D8E8F909192939495969798999A9B9C9D9E9F"
+		"A0A1A2A3A4A5A6A7A8A9AAABACADAEAFB0B1B2B3B4B5B6B7B8B9BABBBCBDBEBFC0C1C2C3C4C5C6C7"
+		"C8C9CACBCCCDCECFD0D1D2D3D4D5D6D7D8D9DADBDCDDDEDFE0E1E2E3E4E5E6E7E8E9EAEBECEDEEEF"
+		"F0F1F2F3F4F5F6F7F8F9FAFBFCFDFE";
+	static const char base32Encoded[] =
+		"AAASEA2EAWDAQCAJBIFS2DIQB6IBCESVCSKTNF22DEPBYHA7D2RUAIJCENUCKJTHFAWUWK3NFWZC8NBT"
+		"GI3VIPJYG66DUQT5HS8V6R4AIFBEGTCFI3DWSUKKJPGE4VURKBIXEW4WKXMFQYC3MJPX2ZK8M7SGC2VD"
+		"NTUYN35IPFXGY5DPP3ZZA6MUQP4HK7VZRB6ZW856RX9H9AEBSKB2JBNGS8EIVCWMTUG27D6SUGJJHFEX"
+		"U4M3TGN4VQQJ5HW9WCS4FI7EWYVKRKFJXKX43MPQX82MDNXVYU45PP72ZG7MZRF7Z496BSQC2RCNMTYH"
+		"3DE6XU8N3ZHN9WGT4MJ7JXQY49NPVYY55VQ77Z9A6HTQH3HF65V8T4RK7RYQ55ZR8D29F69W8Z5RR8H3"
+		"9M7939R8";
+	static const char base64AndHexEncoded[] =
+		"41414543417751464267634943516F4C4441304F4478415245684D554652595847426B6147787764"
+		"486838674953496A4A43556D4A7967704B6973734C5334764D4445794D7A51310A4E6A63344F546F"
+		"375044302B50304242516B4E4552555A4853456C4B5330784E546B395155564A5456465657563168"
+		"5A576C746358563566594746695932526C5A6D646F615770720A6247317562334278636E4E306458"
+		"5A3365486C3665337839666E2B4167594B44684957476834694A696F754D6A5936506B4A47536B35"
+		"53566C7065596D5A71626E4A32656E3643680A6F714F6B7061616E714B6D717136797472712B7773"
+		"624B7A744C573274376935757275387662362F774D484377385446787366497963724C7A4D334F7A"
+		"39445230745055316462580A324E6E6132397A6433742F6734654C6A354F586D352B6A7036757673"
+		"3765377638504879382F5431397666342B6672372F50332B0A";
+	static const char base64URLAndHexEncoded[] =
+		"41414543417751464267634943516F4C4441304F4478415245684D554652595847426B6147787764"
+		"486838674953496A4A43556D4A7967704B6973734C5334764D4445794D7A51314E6A63344F546F37"
+		"5044302D50304242516B4E4552555A4853456C4B5330784E546B395155564A54564656575631685A"
+		"576C746358563566594746695932526C5A6D646F615770726247317562334278636E4E3064585A33"
+		"65486C3665337839666E2D4167594B44684957476834694A696F754D6A5936506B4A47536B355356"
+		"6C7065596D5A71626E4A32656E3643686F714F6B7061616E714B6D717136797472712D7773624B7A"
+		"744C573274376935757275387662365F774D484377385446787366497963724C7A4D334F7A394452"
+		"3074505531646258324E6E6132397A6433745F6734654C6A354F586D352D6A703675767337653776"
+		"38504879385F5431397666342D6672375F50332D";
+
+	std::cout << "\nBase64, Base64URL, Base32 and Base16 coding validation suite running...\n\n";
 
 	fail = !TestFilter(HexEncoder().Ref(), data, 255, (const byte *)hexEncoded, strlen(hexEncoded));
 	std::cout << (fail ? "FAILED    " : "passed    ");
@@ -2488,6 +2499,16 @@ bool ValidateBaseCode()
 	std::cout << "Base64 Decoding\n";
 	pass = pass && !fail;
 
+	fail = !TestFilter(Base64URLEncoder(new HexEncoder).Ref(), data, 255, (const byte *)base64URLAndHexEncoded, strlen(base64URLAndHexEncoded));
+	std::cout << (fail ? "FAILED    " : "passed    ");
+	std::cout << "Base64 URL Encoding\n";
+	pass = pass && !fail;
+
+	fail = !TestFilter(HexDecoder(new Base64URLDecoder).Ref(), (const byte *)base64URLAndHexEncoded, strlen(base64URLAndHexEncoded), data, 255);
+	std::cout << (fail ? "FAILED    " : "passed    ");
+	std::cout << "Base64 URL Decoding\n";
+	pass = pass && !fail;
+
 	return pass;
 }