Fix ACE_HexTools.HexStrToInt to support any length hex strings

EntityIDs are constructed from Low and high 32-bit IDs, the original code here didn't account for entities that have a high ID of zero, and values that were less then 8 characters long.

This new implementation removes the float math and uses bitwise operations to correctly convert to the expected array format in the correct byte order with no length limitations for the input.

addons/core/scripts/Game/ACE_Core/Global/ACE_HexTools.c

@@ -3,64 +3,58 @@ class ACE_HexTools
 {
 	protected static int s_iAscii0 = "0".ToAscii();
 	protected static int s_iAscii9 = "9".ToAscii();
-	protected static int s_iAsciiA = "A".ToAscii();
-	protected static int s_iAsciiF = "F".ToAscii();
-	protected static int s_iAsciiLoA = "a".ToAscii();
-	protected static int s_iAsciiLoF = "f".ToAscii();
-
+	protected static int s_iAsciiA = "a".ToAscii();
+	protected static int s_iAsciiF = "f".ToAscii();
+
 	//------------------------------------------------------------------------------------------------
 	//! Gets int values of hexadecimal string. Expected to be prefixed with "0x"
 	//! Ordered by most significant bits
 	static array<int> HexStringToInt(string hexString)
 	{
-		if (hexString.Substring(0, 2) !=  "0x")
-			return {};
-
-		int numHexChars = hexString.Length() - 2;
-		if (!float.AlmostEqual(Math.Mod(numHexChars, 8), 0))
+		hexString.TrimInPlace();
+		hexString.ToLower();
+		if (!hexString.StartsWith("0x"))
 			return {};
-
-		hexString = hexString.Substring(2, numHexChars);
 
-		int numBit32 = (hexString.Length()) / 8;
 		array<int> result = {};
-		result.Reserve(numBit32);
+		int nibbles = hexString.Length() - 2;
+		int values  = ((nibbles + 7) & ~7) / 8;
+		result.Reserve(values);
 
-		for (int i_bit32 = 0; i_bit32 < numBit32; i_bit32++)
+		int byte  = 0;
+		int value = 0;
+		int count = 0;
+		while(nibbles > 0)
 		{
-			int bit32;
+			int nibble = hexString.Get(nibbles + 1).ToAscii();
+
+			if (nibble >= s_iAscii0 && nibble <= s_iAscii9)
+				nibble -= s_iAscii0;
+			else
+				if (nibble >= s_iAsciiA && nibble <= s_iAsciiF)
+					nibble -= s_iAsciiA - 10;
+				else
+					return {}; //invalid character in string
+
+			value <<= 4;
+			value |= nibble;			
+			--nibbles;
 
-			for (int i_bit4 = 8 * i_bit32; i_bit4 < 8 * (i_bit32 + 1); i_bit4++)
+			if (++count == 8 || nibbles == 0)
 			{
-				int bit4 = HexCharToInt(hexString, index: i_bit4);
-				if (bit4 < 0)
-					return result;
+				int rev = 0;
+				for(int i = 0; i < count; ++i)
+				{
+					rev = (rev << 4) + (value & 0xf);
+					value >>= 4;
+				}
 
-				bit32 = 16 * bit32 + bit4;
-			}
-
-			result.Insert(bit32);
+				result.InsertAt(rev, --values);
+				value = 0;
+				count = 0;
+			}			
 		}
-
+						
 		return result;
 	}
-
-	//------------------------------------------------------------------------------------------------
-	//! Gets int value of a character in a hexadecimal string
-	//! Returns -1 if parsing failed
-	//! \param index Index of the character, 0 by default.
-	static int HexCharToInt(string hexString, int index = 0)
-	{
-        int value = hexString.ToAscii(index);
-		if (value >= s_iAscii0 && value <= s_iAscii9)
-			value -= s_iAscii0;
-		else if (value >= s_iAsciiA && value <= s_iAsciiF)
-			value -= s_iAsciiA - 10;
-		else if (value >= s_iAsciiLoA && value <= s_iAsciiLoF)
-			value -= s_iAsciiLoA - 10;
-		else
-			return -1;
-
-	    return value;
-	}
 }