From 4dbf1dcad441894de3a60e4818a1638fb8b77e84 Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon>
Date: Tue, 8 May 2007 10:50:19 +0000
Subject: [PATCH] mem_realloc: Added assert to check that memory is shrinked,
 not expanded.

---
 src/core/mem.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/core/mem.c b/src/core/mem.c
index df38863c..1ebb5f54 100644
--- a/src/core/mem.c
+++ b/src/core/mem.c
@@ -195,6 +195,10 @@ mem_free(void *rmem)
   sys_sem_signal(mem_sem);
 }
 
+/* In contrast to its name, mem_realloc can only shrink memory, not expand it.
+ * Since the only use (for now) is in pbuf_realloc (which also can only shrink),
+ * this shouldn't be a problem!
+ */
 void *
 mem_realloc(void *rmem, mem_size_t newsize)
 {
@@ -226,6 +230,7 @@ mem_realloc(void *rmem, mem_size_t newsize)
   ptr = (u8_t *)mem - ram;
 
   size = mem->next - ptr - SIZEOF_STRUCT_MEM;
+  LWIP_ASSERT("mem_realloc can only shrink memory", newsize <= size);
 #if MEM_STATS
   lwip_stats.mem.used -= (size - newsize);
 #endif /* MEM_STATS */