X-Git-Url: http://git.maemo.org/git/?p=xmlrpc-c;a=blobdiff_plain;f=lib%2Futil%2Finclude%2Fmallocvar.h;fp=lib%2Futil%2Finclude%2Fmallocvar.h;h=9c4f9947fd1933343b63db1f7975e43f5eb18f8a;hp=0000000000000000000000000000000000000000;hb=ce67d0cdeaa37c3e856e23ae4010480887165630;hpb=e355d4e7962400470f467b88f5568de9c8324475

diff --git a/lib/util/include/mallocvar.h b/lib/util/include/mallocvar.h
new file mode 100644
index 0000000..9c4f994
--- /dev/null
+++ b/lib/util/include/mallocvar.h
@@ -0,0 +1,100 @@
+/* These are some dynamic memory allocation facilities.  They are essentially
+   an extension to C, as they do allocations with a cognizance of C 
+   variables.  You can use them to make C read more like a high level
+   language.
+
+   Before including this, you must define an __inline__ macro if your
+   compiler doesn't recognize it as a keyword.
+*/
+
+#ifndef MALLOCVAR_INCLUDED
+#define MALLOCVAR_INCLUDED
+
+#include "xmlrpc_config.h"
+
+#include <limits.h>
+#include <stdlib.h>
+
+static __inline__ void
+mallocProduct(void **      const resultP, 
+              unsigned int const factor1,
+              unsigned int const factor2) {
+/*----------------------------------------------------------------------------
+   malloc a space whose size in bytes is the product of 'factor1' and
+   'factor2'.  But if that size cannot be represented as an unsigned int,
+   return NULL without allocating anything.  Also return NULL if the malloc
+   fails.
+
+   If either factor is zero, malloc a single byte.
+
+   Note that malloc() actually takes a size_t size argument, so the
+   proper test would be whether the size can be represented by size_t,
+   not unsigned int.  But there is no reliable indication available to
+   us, like UINT_MAX, of what the limitations of size_t are.  We
+   assume size_t is at least as expressive as unsigned int and that
+   nobody really needs to allocate more than 4GB of memory.
+-----------------------------------------------------------------------------*/
+    if (factor1 == 0 || factor2 == 0)
+        *resultP = malloc(1);
+    else {
+        if (UINT_MAX / factor2 < factor1) 
+            *resultP = NULL;
+        else 
+            *resultP = malloc(factor1 * factor2); 
+    }
+}
+
+
+
+static __inline__ void
+reallocProduct(void **      const blockP,
+               unsigned int const factor1,
+               unsigned int const factor2) {
+    
+    if (UINT_MAX / factor2 < factor1) 
+        *blockP = NULL;
+    else 
+        *blockP = realloc(*blockP, factor1 * factor2); 
+}
+
+
+/* IMPLEMENTATION NOTE:  There are huge strict aliasing pitfalls here
+   if you cast pointers, e.g. (void **)
+*/
+
+#define MALLOCARRAY(arrayName, nElements) do { \
+    void * array; \
+    mallocProduct(&array, nElements, sizeof(arrayName[0])); \
+    arrayName = array; \
+} while (0)
+
+#define REALLOCARRAY(arrayName, nElements) { \
+    void * array = arrayName; \
+    reallocProduct(&array, nElements, sizeof(arrayName[0])); \
+    arrayName = array; \
+} while (0)
+
+
+#define MALLOCARRAY_NOFAIL(arrayName, nElements) \
+do { \
+    MALLOCARRAY(arrayName, nElements); \
+    if ((arrayName) == NULL) \
+        abort(); \
+} while(0)
+
+#define REALLOCARRAY_NOFAIL(arrayName, nElements) \
+do { \
+    REALLOCARRAY(arrayName, nElements); \
+    if ((arrayName) == NULL) \
+        abort(); \
+} while(0)
+
+
+#define MALLOCVAR(varName) \
+    varName = malloc(sizeof(*varName))
+
+#define MALLOCVAR_NOFAIL(varName) \
+    do {if ((varName = malloc(sizeof(*varName))) == NULL) abort();} while(0)
+
+#endif
+