Update static ASN1 and add tests

Author: mnadareski

SabreTools.ASN1.Test/AbstractSyntaxNotationOneTests.cs

@@ -0,0 +1,61 @@
+using System;
+using System.IO;
+using Xunit;
+
+namespace SabreTools.ASN1.Test
+{
+    public class AbstractSyntaxNotationOneTests
+    {
+        [Fact]
+        public void Parse_EmptyArray_Throws()
+        {
+            byte[] data = [];
+            Assert.Throws<InvalidDataException>(() => AbstractSyntaxNotationOne.Parse(data, 0));
+        }
+
+        [Fact]
+        public void Parse_ValidArrayNegativeIndex_Throws()
+        {
+            byte[] data = [0x00];
+            Assert.Throws<IndexOutOfRangeException>(() => AbstractSyntaxNotationOne.Parse(data, -1));
+        }
+
+        [Fact]
+        public void Parse_ValidArrayOverIndex_Throws()
+        {
+            byte[] data = [0x00];
+            Assert.Throws<IndexOutOfRangeException>(() => AbstractSyntaxNotationOne.Parse(data, 10));
+        }
+
+        [Fact]
+        public void Parse_ValidMinimalArray()
+        {
+            byte[] data = [0x00];
+            var tlvs = AbstractSyntaxNotationOne.Parse(data, 0);
+
+            var tlv = Assert.Single(tlvs);
+            Assert.Equal(ASN1Type.V_ASN1_EOC, tlv.Type);
+            Assert.Equal(default, tlv.Length);
+            Assert.Null(tlv.Value);
+        }
+
+        [Fact]
+        public void Parse_EmptyStream_Throws()
+        {
+            Stream data = new MemoryStream([], 0, 0, false, false);
+            Assert.Throws<InvalidDataException>(() => AbstractSyntaxNotationOne.Parse(data));
+        }
+
+        [Fact]
+        public void Parse_ValidMinimalStream()
+        {
+            Stream data = new MemoryStream([0x00]);
+            var tlvs = AbstractSyntaxNotationOne.Parse(data);
+
+            var tlv = Assert.Single(tlvs);
+            Assert.Equal(ASN1Type.V_ASN1_EOC, tlv.Type);
+            Assert.Equal(default, tlv.Length);
+            Assert.Null(tlv.Value);
+        }
+    }
+}

SabreTools.ASN1/AbstractSyntaxNotationOne.cs

@@ -1,4 +1,6 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
+using System.IO;
 
 namespace SabreTools.ASN1
 {
@@ -12,16 +14,38 @@ public static class AbstractSyntaxNotationOne
         /// </summary>
         /// <param name="data">Byte array representing the data</param>
         /// <param name="pointer">Current pointer into the data</param>
-        /// <returns></returns>
         public static List<TypeLengthValue> Parse(byte[] data, int pointer)
         {
+            // If the data is invalid
+            if (data.Length == 0)
+                throw new InvalidDataException(nameof(data));
+            if (pointer < 0 || pointer >= data.Length)
+                throw new IndexOutOfRangeException(nameof(pointer));
+
+            using var stream = new MemoryStream(data);
+            stream.Seek(pointer, SeekOrigin.Begin);
+            return Parse(stream);
+        }
+
+        /// <summary>
+        /// Parse a stream into a DER-encoded ASN.1 structure
+        /// </summary>
+        /// <param name="data">Stream representing the data</param>
+        public static List<TypeLengthValue> Parse(Stream data)
+        {
+            // If the data is invalid
+            if (data.Length == 0 || !data.CanRead)
+                throw new InvalidDataException(nameof(data));
+            if (data.Position < 0 || data.Position >= data.Length)
+                throw new IndexOutOfRangeException(nameof(data));
+
             // Create the output list to return
             var topLevelValues = new List<TypeLengthValue>();
 
             // Loop through the data and return all top-level values
-            while (pointer < data.Length)
+            while (data.Position < data.Length)
             {
-                var topLevelValue = new TypeLengthValue(data, ref pointer);
+                var topLevelValue = new TypeLengthValue(data);
                 topLevelValues.Add(topLevelValue);
             }