version 0.3.33

[fms.git] / libs / libtommath / bn_mp_grow.c

diff --git a/libs/libtommath/bn_mp_grow.c b/libs/libtommath/bn_mp_grow.c
new file mode 100644 (file)
index 0000000..2d50058
--- /dev/null
+++ b/libs/libtommath/bn_mp_grow.c
@@ -0,0 +1,57 @@
+#include <tommath.h>
+#ifdef BN_MP_GROW_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
+ */
+
+/* grow as required */
+int mp_grow (mp_int * a, int size)
+{
+  int     i;
+  mp_digit *tmp;
+
+  /* if the alloc size is smaller alloc more ram */
+  if (a->alloc < size) {
+    /* ensure there are always at least MP_PREC digits extra on top */
+    size += (MP_PREC * 2) - (size % MP_PREC);
+
+    /* reallocate the array a->dp
+     *
+     * We store the return in a temporary variable
+     * in case the operation failed we don't want
+     * to overwrite the dp member of a.
+     */
+    tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size);
+    if (tmp == NULL) {
+      /* reallocation failed but "a" is still valid [can be freed] */
+      return MP_MEM;
+    }
+
+    /* reallocation succeeded so set a->dp */
+    a->dp = tmp;
+
+    /* zero excess digits */
+    i        = a->alloc;
+    a->alloc = size;
+    for (; i < a->alloc; i++) {
+      a->dp[i] = 0;
+    }
+  }
+  return MP_OKAY;
+}
+#endif
+
+/* $Source: /cvs/libtom/libtommath/bn_mp_grow.c,v $ */
+/* $Revision: 1.3 $ */
+/* $Date: 2006/03/31 14:18:44 $ */