If string is too long, skip bytes at the end instead of throwing an exception.

Author: brianberns

src/ImageSharp/Formats/Tiff/Compression/Decompressors/LzwString.cs

@@ -69,25 +69,33 @@ public int WriteTo(Span<byte> buffer, int offset)
             return 0;
         }
 
-        if (this.Length == 1)
+        int available = buffer.Length - offset;
+        if (available <= 0)
         {
-            buffer[offset] = this.value;
-            return 1;
+            return 0;
+        }
+
+        int numToWrite = this.Length;
+        if (numToWrite > available)
+        {
+            numToWrite = available;
         }
 
         LzwString e = this;
-        int endIdx = this.Length - 1;
-        if (offset + endIdx >= buffer.Length)
+
+        // if string is too long, skip bytes at the end
+        int toSkip = this.Length - numToWrite;
+        for (int i = 0; i < toSkip; i++)
         {
-            TiffThrowHelper.ThrowImageFormatException("Error reading lzw compressed stream. Either pixel buffer to write to is too small or code length is invalid!");
+            e = e.previous;
         }
 
-        for (int i = endIdx; i >= 0; i--)
+        for (int i = numToWrite - 1; i >= 0; i--)
         {
             buffer[offset + i] = e.value;
             e = e.previous;
         }
 
-        return this.Length;
+        return numToWrite;
     }
 }