From bb1227116baa6c7143fffd87accef8b6e423ebe6 Mon Sep 17 00:00:00 2001
From: Florian Hartwig <florian.j.hartwig@gmail.com>
Date: Wed, 25 Mar 2015 01:11:25 +0100
Subject: [PATCH] Fix panics on operations on 0-capacity RingBuf

---
 src/ring.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/ring.rs b/src/ring.rs
index 89e7940..fe29db4 100644
--- a/src/ring.rs
+++ b/src/ring.rs
@@ -60,6 +60,9 @@ impl RingBuf {
     }
 
     fn advance_reader(&mut self, mut cnt: usize) {
+        if self.cap == 0 {
+            return;
+        }
         cnt = cmp::min(cnt, self.read_remaining());
 
         self.pos += cnt;
@@ -162,6 +165,9 @@ impl MutBuf for RingBuf {
     }
 
     fn mut_bytes(&mut self) -> &mut [u8] {
+        if self.cap == 0 {
+            return self.as_mut_slice();
+        }
         let mut from;
         let mut to;