[PATCH] added malloc usable size and test

[zack leung]

---
 cpukit/include/rtems/libcsupport.h        |  8 ++++++-
 cpukit/libcsupport/src/mallocusablesize.c | 28 +++++++++++++++++++++++
 spec/build/cpukit/librtemscpu.yml         |  1 +
 testsuites/libtests/malloctest/init.c     | 15 +++++++++++-
 4 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 cpukit/libcsupport/src/mallocusablesize.c

diff --git a/cpukit/include/rtems/libcsupport.h b/cpukit/include/rtems/libcsupport.h
index f4be4cfc9a..1fe0f6735f 100644
--- a/cpukit/include/rtems/libcsupport.h
+++ b/cpukit/include/rtems/libcsupport.h
@@ -73,7 +73,12 @@ extern size_t malloc_free_space(void);
  * Find amount of free heap remaining.
  */
 extern int malloc_info(Heap_Information_block *the_info);
-
+/**
+ * @brief Get malloc status information.
+ * 
+ * Find the usable size of the block of memory .
+ */
+extern size_t malloc_usable_size(void *ptr);
 /*
  *  Prototypes required to install newlib reentrancy user extension
  */
@@ -185,6 +190,7 @@ bool rtems_resource_snapshot_equal(
  */
 bool rtems_resource_snapshot_check(const rtems_resource_snapshot *snapshot);
 
+
 /** @} */
 
 #ifdef __cplusplus
diff --git a/cpukit/libcsupport/src/mallocusablesize.c b/cpukit/libcsupport/src/mallocusablesize.c
new file mode 100644
index 0000000000..10114182a6
--- /dev/null
+++ b/cpukit/libcsupport/src/mallocusablesize.c
@@ -0,0 +1,28 @@
+/*
+ *  COPYRIGHT (c) 1989-2010.
+ *  On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.org/license/LICENSE.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/libcsupport.h>
+#include <rtems/malloc.h>
+#include <rtems/score/heapimpl.h>
+
+Heap_Control *heap_ptr;
+size_t malloc_usable_size(void *ptr) {
+  uintptr_t size;
+  if (ptr == NULL) {
+    return 0;
+  }
+  
+  heap_ptr = malloc_get_heap_pointer();
+  _Heap_Size_of_alloc_area(heap_ptr, ptr, &size);
+
+  return size;
+}
diff --git a/spec/build/cpukit/librtemscpu.yml b/spec/build/cpukit/librtemscpu.yml
index 7d6dbae0db..5902008c94 100644
--- a/spec/build/cpukit/librtemscpu.yml
+++ b/spec/build/cpukit/librtemscpu.yml
@@ -670,6 +670,7 @@ source:
 - cpukit/libcsupport/src/lseek.c
 - cpukit/libcsupport/src/lstat.c
 - cpukit/libcsupport/src/malloc.c
+- cpukit/libcsupport/src/mallocusablesize.c 
 - cpukit/libcsupport/src/malloc_deferred.c
 - cpukit/libcsupport/src/malloc_dirtier.c
 - cpukit/libcsupport/src/malloc_walk.c
diff --git a/testsuites/libtests/malloctest/init.c b/testsuites/libtests/malloctest/init.c
index a33764177d..2202546719 100644
--- a/testsuites/libtests/malloctest/init.c
+++ b/testsuites/libtests/malloctest/init.c
@@ -1362,6 +1362,18 @@ static void test_alloc_zero_size(void)
   rtems_test_assert( p == NULL );
   rtems_test_assert( errno == -1 );
 }
+static void test_usablesize(void)
+{
+  int * a = malloc(sizeof( int )*100);
+  int alloc_size=sizeof( int ) *100 ;
+  rtems_test_assert(  malloc_usable_size(a) <= alloc_size + CPU_HEAP_ALIGNMENT);
+  free(a);
+
+  char * b = malloc(sizeof(char)*100);
+  int alloc_size2=sizeof(char) *100 ; 
+  rtems_test_assert( malloc_usable_size ( b ) <= alloc_size2 + CPU_HEAP_ALIGNMENT);
+  free(b);
+}
 
 rtems_task Init(
   rtems_task_argument argument
@@ -1405,6 +1417,7 @@ rtems_task Init(
   test_protected_heap_info();
   test_rtems_heap_allocate_aligned_with_boundary();
   test_rtems_malloc();
+  test_usablesize();
   test_rtems_calloc();
   test_greedy_allocate();
   test_alloc_zero_size();
@@ -1524,4 +1537,4 @@ RTEMS_SYSINIT_ITEM(
   test_early_malloc,
   RTEMS_SYSINIT_INITIAL_EXTENSIONS,
   RTEMS_SYSINIT_ORDER_FIRST
-);
+);
\ No newline at end of file
-- 
2.35.1