[Proto] Fixed regression & inference of EncodeString

Author: Linwenxuan04

Lagrange.Proto/Primitives/ProtoWriter.cs

@@ -44,7 +44,7 @@ public void EncodeString(ReadOnlySpan<char> str)
         int utf16Max = ProtoConstants.MaxExpansionFactorWhileTranscoding * str.Length;
         if (_memory.Length < utf16Max) Grow(utf16Max);
 
-        if (str.Length > min && str.Length < max) // falls within the range
+        if (str.Length > min && utf16Max < max) // falls within the range
         {
             BytesPending += count;
             var status = ProtoWriteHelper.ToUtf8(str, _memory.Span[BytesPending..], out int written);

Lagrange.Proto/Utility/ProtoHelper.cs

@@ -7,42 +7,19 @@ namespace Lagrange.Proto.Utility;
 
 public static class ProtoHelper
 {
-    /*
-     *     private static final int[] VAR_INT_LENGTHS = new int[65];
+    private static readonly int[] VarIntValues;
 
-    static {
-        for (int i = 0; i <= 64; ++i) {
-            VAR_INT_LENGTHS[i] = (63 - i) / 7;
-        }
-    }
-     */
-    
-    private static readonly int[] VarIntLengths = new int[65];
-    
     static ProtoHelper()
     {
-        for (int i = 0; i <= 64; ++i) VarIntLengths[i] = (63 - i) / 7;
+        VarIntValues = new int[5];
+        for (int i = 0; i < VarIntValues.Length; i++) VarIntValues[i] = 1 << (7 * i);
     }
-    
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    internal static int GetVarIntMin(int length) => length switch
-    {
-        1 => (1 << 0),
-        2 => (1 << 7),
-        3 => (1 << 14),
-        4 => (1 << 21),
-        _ => throw new ArgumentOutOfRangeException(nameof(length), "Invalid length for VarInt.")
-    };
+    internal static int GetVarIntMin(int length) => VarIntValues[length - 1];
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    internal static int GetVarIntMax(int length) => length switch
-    {
-        1 => (1 << 7) - 1,
-        2 => (1 << 14) - 1,
-        3 => (1 << 21) - 1,
-        4 => (1 << 28) - 1,
-        _ => throw new ArgumentOutOfRangeException(nameof(length), "Invalid length for VarInt.")
-    };
+    internal static int GetVarIntMax(int length) => VarIntValues[length] - 1;
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static unsafe int GetVarIntLength<T>(T value) where T : unmanaged, INumberBase<T>