Merge branch 'main' into zs/web-ui-improvements

1 files changed, 190 insertions, 2 deletions

diff --git a/src/zencore/base64.cpp b/src/zencore/base64.cpp
index 1f56ee6c3..fdf5f2d66 100644
--- a/src/zencore/base64.cpp
+++ b/src/zencore/base64.cpp
@@ -1,6 +1,10 @@
 // Copyright Epic Games, Inc. All Rights Reserved.
 
 #include <zencore/base64.h>
+#include <zencore/string.h>
+#include <zencore/testing.h>
+
+#include <string>
 
 namespace zen {
 
@@ -11,7 +15,6 @@ static const uint8_t EncodingAlphabet[64] = {'A', 'B', 'C', 'D', 'E', 'F', 'G',
 											 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'};
 
 /** The table used to convert an ascii character into a 6 bit value */
-#if 0
 static const uint8_t DecodingAlphabet[256] = {
 	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,	 // 0x00-0x0f
 	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,	 // 0x10-0x1f
@@ -30,7 +33,6 @@ static const uint8_t DecodingAlphabet[256] = {
 	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,	 // 0xe0-0xef
 	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF	 // 0xf0-0xff
 };
-#endif	// 0
 
 template<typename CharType>
 uint32_t
@@ -104,4 +106,190 @@ Base64::Encode(const uint8_t* Source, uint32_t Length, CharType* Dest)
 template uint32_t Base64::Encode<char>(const uint8_t* Source, uint32_t Length, char* Dest);
 template uint32_t Base64::Encode<wchar_t>(const uint8_t* Source, uint32_t Length, wchar_t* Dest);
 
+template<typename CharType>
+bool
+Base64::Decode(const CharType* Source, uint32_t Length, uint8_t* Dest, uint32_t& OutLength)
+{
+	// Length must be a multiple of 4
+	if (Length % 4 != 0)
+	{
+		OutLength = 0;
+		return false;
+	}
+
+	uint8_t* DecodedBytes = Dest;
+
+	// Process 4 encoded characters at a time, producing 3 decoded bytes
+	while (Length > 0)
+	{
+		// Count padding characters at the end
+		uint32_t PadCount = 0;
+		if (Source[3] == '=')
+		{
+			PadCount++;
+			if (Source[2] == '=')
+			{
+				PadCount++;
+			}
+		}
+
+		// Look up each character in the decoding table
+		uint8_t A = DecodingAlphabet[static_cast<uint8_t>(Source[0])];
+		uint8_t B = DecodingAlphabet[static_cast<uint8_t>(Source[1])];
+		uint8_t C = (PadCount >= 2) ? 0 : DecodingAlphabet[static_cast<uint8_t>(Source[2])];
+		uint8_t D = (PadCount >= 1) ? 0 : DecodingAlphabet[static_cast<uint8_t>(Source[3])];
+
+		// Check for invalid characters (0xFF means not in the base64 alphabet)
+		if (A == 0xFF || B == 0xFF || C == 0xFF || D == 0xFF)
+		{
+			OutLength = 0;
+			return false;
+		}
+
+		// Reconstruct the 24-bit value from 4 6-bit chunks
+		uint32_t ByteTriplet = (A << 18) | (B << 12) | (C << 6) | D;
+
+		// Extract the 3 bytes
+		*DecodedBytes++ = static_cast<uint8_t>(ByteTriplet >> 16);
+		if (PadCount < 2)
+		{
+			*DecodedBytes++ = static_cast<uint8_t>((ByteTriplet >> 8) & 0xFF);
+		}
+		if (PadCount < 1)
+		{
+			*DecodedBytes++ = static_cast<uint8_t>(ByteTriplet & 0xFF);
+		}
+
+		Source += 4;
+		Length -= 4;
+	}
+
+	OutLength = uint32_t(DecodedBytes - Dest);
+	return true;
+}
+
+template bool Base64::Decode<char>(const char* Source, uint32_t Length, uint8_t* Dest, uint32_t& OutLength);
+template bool Base64::Decode<wchar_t>(const wchar_t* Source, uint32_t Length, uint8_t* Dest, uint32_t& OutLength);
+
+//////////////////////////////////////////////////////////////////////////
+//
+// Testing related code follows...
+//
+
+#if ZEN_WITH_TESTS
+
+using namespace std::string_literals;
+
+TEST_CASE("Base64")
+{
+	auto EncodeString = [](std::string_view Input) -> std::string {
+		std::string Result;
+		Result.resize(Base64::GetEncodedDataSize(uint32_t(Input.size())));
+		Base64::Encode(reinterpret_cast<const uint8_t*>(Input.data()), uint32_t(Input.size()), Result.data());
+		return Result;
+	};
+
+	auto DecodeString = [](std::string_view Input) -> std::string {
+		std::string Result;
+		Result.resize(Base64::GetMaxDecodedDataSize(uint32_t(Input.size())));
+		uint32_t DecodedLength = 0;
+		bool	 Success = Base64::Decode(Input.data(), uint32_t(Input.size()), reinterpret_cast<uint8_t*>(Result.data()), DecodedLength);
+		CHECK(Success);
+		Result.resize(DecodedLength);
+		return Result;
+	};
+
+	SUBCASE("Encode")
+	{
+		CHECK(EncodeString("") == ""s);
+		CHECK(EncodeString("f") == "Zg=="s);
+		CHECK(EncodeString("fo") == "Zm8="s);
+		CHECK(EncodeString("foo") == "Zm9v"s);
+		CHECK(EncodeString("foob") == "Zm9vYg=="s);
+		CHECK(EncodeString("fooba") == "Zm9vYmE="s);
+		CHECK(EncodeString("foobar") == "Zm9vYmFy"s);
+	}
+
+	SUBCASE("Decode")
+	{
+		CHECK(DecodeString("") == ""s);
+		CHECK(DecodeString("Zg==") == "f"s);
+		CHECK(DecodeString("Zm8=") == "fo"s);
+		CHECK(DecodeString("Zm9v") == "foo"s);
+		CHECK(DecodeString("Zm9vYg==") == "foob"s);
+		CHECK(DecodeString("Zm9vYmE=") == "fooba"s);
+		CHECK(DecodeString("Zm9vYmFy") == "foobar"s);
+	}
+
+	SUBCASE("RoundTrip")
+	{
+		auto RoundTrip = [&](const std::string& Input) {
+			std::string Encoded = EncodeString(Input);
+			std::string Decoded = DecodeString(Encoded);
+			CHECK(Decoded == Input);
+		};
+
+		RoundTrip("Hello, World!");
+		RoundTrip("Base64 encoding test with various lengths");
+		RoundTrip("A");
+		RoundTrip("AB");
+		RoundTrip("ABC");
+		RoundTrip("ABCD");
+		RoundTrip("\x00\x01\x02\xff\xfe\xfd"s);
+	}
+
+	SUBCASE("BinaryRoundTrip")
+	{
+		// Test with all byte values 0-255
+		uint8_t AllBytes[256];
+		for (int i = 0; i < 256; ++i)
+		{
+			AllBytes[i] = static_cast<uint8_t>(i);
+		}
+
+		char Encoded[Base64::GetEncodedDataSize(256) + 1];
+		Base64::Encode(AllBytes, 256, Encoded);
+
+		uint8_t	 Decoded[256];
+		uint32_t DecodedLength = 0;
+		bool	 Success	   = Base64::Decode(Encoded, uint32_t(strlen(Encoded)), Decoded, DecodedLength);
+		CHECK(Success);
+		CHECK(DecodedLength == 256);
+		CHECK(memcmp(AllBytes, Decoded, 256) == 0);
+	}
+
+	SUBCASE("DecodeInvalidInput")
+	{
+		uint8_t	 Dest[64];
+		uint32_t OutLength = 0;
+
+		// Length not a multiple of 4
+		CHECK_FALSE(Base64::Decode("abc", 3u, Dest, OutLength));
+
+		// Invalid character
+		CHECK_FALSE(Base64::Decode("ab!d", 4u, Dest, OutLength));
+	}
+
+	SUBCASE("EncodedDataSize")
+	{
+		CHECK(Base64::GetEncodedDataSize(0) == 0);
+		CHECK(Base64::GetEncodedDataSize(1) == 4);
+		CHECK(Base64::GetEncodedDataSize(2) == 4);
+		CHECK(Base64::GetEncodedDataSize(3) == 4);
+		CHECK(Base64::GetEncodedDataSize(4) == 8);
+		CHECK(Base64::GetEncodedDataSize(5) == 8);
+		CHECK(Base64::GetEncodedDataSize(6) == 8);
+	}
+
+	SUBCASE("MaxDecodedDataSize")
+	{
+		CHECK(Base64::GetMaxDecodedDataSize(0) == 0);
+		CHECK(Base64::GetMaxDecodedDataSize(4) == 3);
+		CHECK(Base64::GetMaxDecodedDataSize(8) == 6);
+		CHECK(Base64::GetMaxDecodedDataSize(12) == 9);
+	}
+}
+
+#endif
+
 }  // namespace zen