Add well-known OIDs to System.Formats.Asn1

This adds most of the OIDs that are read or written during the execution of any of the
crypto tests or SslStream tests as a well-known pattern of bytes and a pre-allocated/
const/interned string.

Reading a well-known OID drops from ~300ns to ~60ns and saves on allocating the output
string, and possibly an `int[]` in BigInteger for large-RID OIDs, while increasing the
cost for a less well-known OID by about 40ns.

Writing a well-known OID drops from ~1200ns to ~90ns, and increases the cost for a less
well-known OID by only about 10ns.

For purposes of this initial list, an oid was well-known if (more or less):
* It was the output of ReadObjectIdentifier more than twice, and
* It was not a facetious/test value (e.g. 0.0), and
* It was not a vendor-specific Certificate Practices Statement; or
* It was an obviously linked OID potentially skewed out by our test data
  * e.g. EcdsaWithSha512 would be automatically included by closeness to EcdsaWithSha256.

src/libraries/System.Formats.Asn1/src/System.Formats.Asn1.csproj

@@ -53,6 +53,7 @@ System.Formats.Asn1.AsnWriter</PackageDescription>
     <Compile Include="System\Formats\Asn1\SetOfValueComparer.cs" />
     <Compile Include="System\Formats\Asn1\TagClass.cs" />
     <Compile Include="System\Formats\Asn1\UniversalTagNumber.cs" />
+    <Compile Include="System\Formats\Asn1\WellKnownOids.cs" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == '$(NetCoreAppCurrent)'">

src/libraries/System.Formats.Asn1/src/System/Formats/Asn1/AsnDecoder.Oid.cs

@@ -53,8 +53,27 @@ public static partial class AsnDecoder
             out int bytesConsumed,
             Asn1Tag? expectedTag = null)
         {
-            // TODO: Inline this call when it won't cause a PR/diff problem.
-            return ReadObjectIdentifier(source, ruleSet, expectedTag, out bytesConsumed);
+            // T-REC-X.690-201508 sec 8.19.1
+            ReadOnlySpan<byte> contents = GetPrimitiveContentSpan(
+                source,
+                ruleSet,
+                expectedTag ?? Asn1Tag.ObjectIdentifier,
+                UniversalTagNumber.ObjectIdentifier,
+                out int consumed);
+
+#if NETCOREAPP
+            string? wellKnown = WellKnownOids.GetValue(contents);
+
+            if (wellKnown is not null)
+            {
+                bytesConsumed = consumed;
+                return wellKnown;
+            }
+#endif
+
+            string ret = ReadObjectIdentifier(contents);
+            bytesConsumed = consumed;
+            return ret;
         }
 
         private static void ReadSubIdentifier(
@@ -172,20 +191,8 @@ public static partial class AsnDecoder
             CryptoPool.Return(tmpBytes, bytesWritten);
         }
 
-        private static string ReadObjectIdentifier(
-            ReadOnlySpan<byte> source,
-            AsnEncodingRules ruleSet,
-            Asn1Tag? expectedTag,
-            out int totalBytesRead)
+        private static string ReadObjectIdentifier(ReadOnlySpan<byte> contents)
         {
-            // T-REC-X.690-201508 sec 8.19.1
-            ReadOnlySpan<byte> contents = GetPrimitiveContentSpan(
-                source,
-                ruleSet,
-                expectedTag ?? Asn1Tag.ObjectIdentifier,
-                UniversalTagNumber.ObjectIdentifier,
-                out int consumed);
-
             // T-REC-X.690-201508 sec 8.19.2 says the minimum length is 1
             if (contents.Length < 1)
             {
@@ -278,7 +285,6 @@ public static partial class AsnDecoder
                 contents = contents.Slice(bytesRead);
             }
 
-            totalBytesRead = consumed;
             return builder.ToString();
         }
     }

src/libraries/System.Formats.Asn1/src/System/Formats/Asn1/AsnWriter.Oid.cs

@@ -59,6 +59,19 @@ public void WriteObjectIdentifier(ReadOnlySpan<char> oidValue, Asn1Tag? tag = nu
         {
             CheckUniversalTag(tag, UniversalTagNumber.ObjectIdentifier);
 
+#if NETCOREAPP
+            ReadOnlySpan<byte> wellKnownContents = WellKnownOids.GetContents(oidValue);
+
+            if (!wellKnownContents.IsEmpty)
+            {
+                WriteTag(tag?.AsPrimitive() ?? Asn1Tag.ObjectIdentifier);
+                WriteLength(wellKnownContents.Length);
+                wellKnownContents.CopyTo(_buffer.AsSpan(_offset));
+                _offset += wellKnownContents.Length;
+                return;
+            }
+#endif
+
             WriteObjectIdentifierCore(tag?.AsPrimitive() ?? Asn1Tag.ObjectIdentifier, oidValue);
         }