add fluid_align_ptr() for aligning pointers

test/test_pointer_alignment.c

@@ -0,0 +1,31 @@
+
+#include "test.h"
+#include "utils/fluid_sys.h"
+
+
+// test for fluid_align_ptr()
+int main(void)
+{
+    unsigned int align;
+    uintptr_t ptr, aligned_ptr;
+    
+    for(align = 32; align <= 4*1024u; align <<= 1)
+    {
+        for(ptr = 0; ptr <= (align<<10); ptr++)
+        {
+            char* tmp = fluid_align_ptr((char*)ptr, align);
+            aligned_ptr = (uintptr_t)tmp;
+            
+            // pointer must be aligned properly
+            TEST_ASSERT(aligned_ptr % align == 0);
+            
+            // aligned pointer must not be smaller than ptr
+            TEST_ASSERT(aligned_ptr >= ptr);
+            
+            // aligned pointer must not be bigger than alignment
+            TEST_ASSERT(aligned_ptr < ptr + align);
+        }
+    }
+    
+    return EXIT_SUCCESS;
+}