[incubator-nuttx] branch master updated: mm/circbuf: fix the problem of dividing by zero.

[xiaoxiang]

This is an automated email from the ASF dual-hosted git repository.

xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git


The following commit(s) were added to refs/heads/master by this push:
     new 6427187  mm/circbuf: fix the problem of dividing by zero.
6427187 is described below

commit 642718709df59b81f7c21c0cf780bc97c1f8217b
Author: dongjiuzhu <dongjiuz...@xiaomi.com>
AuthorDate: Mon Nov 30 16:24:41 2020 +0800

    mm/circbuf: fix the problem of dividing by zero.
    
    N/A
    
    Change-Id: I78a5cae0f782bc2c09848ebda9589dc53809e089
    Signed-off-by: dongjiuzhu <dongjiuz...@xiaomi.com>
---
 mm/circbuf/circbuf.c | 44 +++++++++++++++++++++++++++++++-------------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/mm/circbuf/circbuf.c b/mm/circbuf/circbuf.c
index cef8e13..0912e52 100644
--- a/mm/circbuf/circbuf.c
+++ b/mm/circbuf/circbuf.c
@@ -102,26 +102,29 @@ int circbuf_init(FAR struct circbuf_s *circ, FAR void 
*base, size_t bytes)
 
 int circbuf_resize(FAR struct circbuf_s *circ, size_t bytes)
 {
-  FAR void *tmp;
-  size_t len;
+  FAR void *tmp = NULL;
+  size_t len = 0;
 
   DEBUGASSERT(circ);
   DEBUGASSERT(!circ->external);
 
-  tmp = kmm_malloc(bytes);
-  if (!tmp)
+  if (bytes)
     {
-      return -ENOMEM;
-    }
+      tmp = kmm_malloc(bytes);
+      if (!tmp)
+        {
+          return -ENOMEM;
+        }
 
-  len = circbuf_used(circ);
-  if (bytes < len)
-    {
-      circbuf_skip(circ, len - bytes);
-      len = bytes;
-    }
+      len = circbuf_used(circ);
+      if (bytes < len)
+        {
+          circbuf_skip(circ, len - bytes);
+          len = bytes;
+        }
 
-  circbuf_read(circ, tmp, len);
+      circbuf_read(circ, tmp, len);
+    }
 
   kmm_free(circ->base);
 
@@ -276,6 +279,11 @@ ssize_t circbuf_peek(FAR struct circbuf_s *circ,
 
   DEBUGASSERT(circ);
 
+  if (!circ->size)
+    {
+      return 0;
+    }
+
   len = circbuf_used(circ);
   off = circ->tail % circ->size;
 
@@ -394,6 +402,11 @@ ssize_t circbuf_write(FAR struct circbuf_s *circ,
   DEBUGASSERT(circ);
   DEBUGASSERT(src || !bytes);
 
+  if (!circ->size)
+    {
+      return 0;
+    }
+
   space = circbuf_space(circ);
   off = circ->head % circ->size;
   if (bytes > space)
@@ -446,6 +459,11 @@ ssize_t circbuf_overwrite(FAR struct circbuf_s *circ,
   DEBUGASSERT(circ);
   DEBUGASSERT(src || !bytes);
 
+  if (!circ->size)
+    {
+      return 0;
+    }
+
   if (bytes > circ->size)
     {
       src += bytes - circ->size;