Improving throw helper.

Author: Stefán J. Sigurðarson

projects/RabbitMQ.Client/client/impl/WireFormatting.cs

@@ -40,50 +40,46 @@
 
 namespace RabbitMQ.Client.Impl
 {
-    // * DESCRIPTION TAKEN FROM MS REFERENCE SOURCE *
-    // https://github.com/microsoft/referencesource/blob/master/mscorlib/system/decimal.cs
-    // The lo, mid, hi, and flags fields contain the representation of the
-    // Decimal value. The lo, mid, and hi fields contain the 96-bit integer
-    // part of the Decimal. Bits 0-15 (the lower word) of the flags field are
-    // unused and must be zero; bits 16-23 contain must contain a value between
-    // 0 and 28, indicating the power of 10 to divide the 96-bit integer part
-    // by to produce the Decimal value; bits 24-30 are unused and must be zero;
-    // and finally bit 31 indicates the sign of the Decimal value, 0 meaning
-    // positive and 1 meaning negative.
-    readonly struct DecimalData
+    internal static class WireFormatting
     {
-        public readonly uint Flags;
-        public readonly uint Hi;
-        public readonly uint Lo;
-        public readonly uint Mid;
-
-        internal DecimalData(uint flags, uint hi, uint lo, uint mid)
+        // * DESCRIPTION TAKEN FROM MS REFERENCE SOURCE *
+        // https://github.com/microsoft/referencesource/blob/master/mscorlib/system/decimal.cs
+        // The lo, mid, hi, and flags fields contain the representation of the
+        // Decimal value. The lo, mid, and hi fields contain the 96-bit integer
+        // part of the Decimal. Bits 0-15 (the lower word) of the flags field are
+        // unused and must be zero; bits 16-23 contain must contain a value between
+        // 0 and 28, indicating the power of 10 to divide the 96-bit integer part
+        // by to produce the Decimal value; bits 24-30 are unused and must be zero;
+        // and finally bit 31 indicates the sign of the Decimal value, 0 meaning
+        // positive and 1 meaning negative.
+        readonly struct DecimalData
         {
-            Flags = flags;
-            Hi = hi;
-            Lo = lo;
-            Mid = mid;
+            public readonly uint Flags;
+            public readonly uint Hi;
+            public readonly uint Lo;
+            public readonly uint Mid;
+
+            internal DecimalData(uint flags, uint hi, uint lo, uint mid)
+            {
+                Flags = flags;
+                Hi = hi;
+                Lo = lo;
+                Mid = mid;
+            }
         }
-    }
 
-    internal static class WireFormatting
-    {
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static decimal ReadDecimal(ReadOnlySpan<byte> span)
         {
             byte scale = span[0];
-            ValidateDecimalScale(scale);
-            uint unsignedMantissa = NetworkOrderDeserializer.ReadUInt32(span.Slice(1));
-            var data = new DecimalData(((uint)(scale << 16)) | unsignedMantissa & 0x80000000, 0, unsignedMantissa & 0x7FFFFFFF, 0);
-            return Unsafe.As<DecimalData, decimal>(ref data);
-        }
-
-        private static void ValidateDecimalScale(byte scale)
-        {
             if (scale > 28)
             {
-                throw new SyntaxErrorException($"Unrepresentable AMQP decimal table field: scale={scale}");
+                ThrowInvalidDecimalScale(scale);
             }
+
+            uint unsignedMantissa = NetworkOrderDeserializer.ReadUInt32(span.Slice(1));
+            var data = new DecimalData(((uint)(scale << 16)) | unsignedMantissa & 0x80000000, 0, unsignedMantissa & 0x7FFFFFFF, 0);
+            return Unsafe.As<DecimalData, decimal>(ref data);
         }
 
         public static IList ReadArray(ReadOnlySpan<byte> span, out int bytesRead)
@@ -880,5 +876,10 @@ private static int ThrowWireFormattingException(decimal value)
         {
             throw new WireFormattingException("Decimal overflow in AMQP encoding", value);
         }
+
+        private static decimal ThrowInvalidDecimalScale(int scale)
+        {
+            throw new SyntaxErrorException($"Unrepresentable AMQP decimal table field: scale={scale}");
+        }
     }
 }