From 88d4a5630250ab0a2effdec63a8bddf4c74ff332 Mon Sep 17 00:00:00 2001
From: Justin Masters <justin.masters@gmail.com>
Date: Thu, 12 Dec 2024 21:53:12 +1100
Subject: [PATCH] Add CappedMemoryStream

---
 jose-jwt/compression/CappedMemoryStream.cs | 34 ++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 jose-jwt/compression/CappedMemoryStream.cs

diff --git a/jose-jwt/compression/CappedMemoryStream.cs b/jose-jwt/compression/CappedMemoryStream.cs
new file mode 100644
index 00000000..2d7fb9ea
--- /dev/null
+++ b/jose-jwt/compression/CappedMemoryStream.cs
@@ -0,0 +1,34 @@
+using System;
+using System.IO;
+
+namespace Jose;
+
+public class CappedMemoryStream : MemoryStream
+{
+    private readonly long maxCapacity;
+
+    public CappedMemoryStream(long maxCapacity)
+    {
+        this.maxCapacity = maxCapacity;
+    }
+
+    public override void Write(byte[] buffer, int offset, int count)
+    {
+        if (Length + Math.Min(count, buffer.Length - offset) > maxCapacity)
+        {
+            throw new NotSupportedException("Exceeding maximum memory stream size.");
+        }
+
+        base.Write(buffer, offset, count);
+    }
+
+    public override void WriteByte(byte value)
+    {
+        if (Length + 1 > maxCapacity)
+        {
+            throw new NotSupportedException("Exceeding maximum memory stream size.");
+        }
+
+        base.WriteByte(value);
+    }
+}
\ No newline at end of file