From b0ba8231d75c0624d42ba408ff896de41b94281f Mon Sep 17 00:00:00 2001
From: Kimbsen <kim@jotta.no>
Date: Thu, 15 Apr 2021 13:15:41 +0200
Subject: [PATCH] fix panic when setting rate to lower than tokens consumed
 last interval

fixes this by not attempting read/write on invalid slice ranges
---
 iocap.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/iocap.go b/iocap.go
index 909a688..e28f165 100644
--- a/iocap.go
+++ b/iocap.go
@@ -39,6 +39,9 @@ func (r *Reader) Read(p []byte) (n int, err error) {
 	for n < len(p) {
 		// Ask for enough space to fit all remaining bytes
 		v := r.bucket.insert(len(p) - n)
+		if v < 0 {
+			return
+		}
 
 		// Read from src into the byte range in p
 		v, err = r.src.Read(p[n : n+v])
@@ -81,6 +84,9 @@ func (w *Writer) Write(p []byte) (n int, err error) {
 	for n < len(p) {
 		// Ask for enough space to write p completely.
 		v := w.bucket.insert(len(p) - n)
+		if v < 0 {
+			return
+		}
 
 		// Write from the byte offset on p into the writer.
 		v, err = w.dst.Write(p[n : n+v])