diff --git a/library/ringbuffer/ringbuffer.c b/library/ringbuffer/ringbuffer.c
index f8ac6fb..76d40cd 100644
--- a/library/ringbuffer/ringbuffer.c
+++ b/library/ringbuffer/ringbuffer.c
@@ -78,6 +78,7 @@ void rd_RingbufferInit(rd_ringbuf_t *rb, char *pool, int size)
 int rd_RingbufferSpaceLen(rd_ringbuf_t *rb)
 {
     if (!rb) return -1;
+    int iRet = 0;
 
     unsigned short wi = ATOMIC_LOAD(&rb->m_sWriteIndex, unsigned short, ATOMIC_ORDER_ACQUIRE);
     unsigned short ri = ATOMIC_LOAD(&rb->m_sReadIndex, unsigned short, ATOMIC_ORDER_RELAXED);
@@ -85,9 +86,19 @@ int rd_RingbufferSpaceLen(rd_ringbuf_t *rb)
     unsigned char rb_m = ATOMIC_LOAD(&rb->m_bReadMirror, unsigned char, ATOMIC_ORDER_RELAXED);
 
     if (wb == rb_m) {
-        return rb->m_iBufsize - (wi - ri);
+    	iRet = rb->m_iBufsize - (wi - ri);
     } else {
-        return ri - wi;
+    	iRet =  ri - wi;
+    }
+
+    if (iRet > 0)
+    {
+    	return iRet;
+    }
+    else
+    {
+    	log_e("wb = %d, rb_m = %d, wi = %d, ri = %d", wb, rb_m, wi, ri);
+    	return 0;
     }
 }