gstutils: Add special random unit test for 64 scaling functions

This tests 100000 random multiplications/divisions of all scaling
function variants and compares the result with the result that is
generated by GMP on the same input.

For this check for GSL and GMP during configure but only use
it for this single unit test.

Testing functions were provided by Kipp Cannon <kcannon@ligo.caltech.edu>

configure.ac

@@ -323,6 +323,25 @@ if test "x$HAVE_WINSOCK2_H" = "xyes"; then
   AC_SUBST(WIN32_LIBS)
 fi
 
+dnl check for GMP/GSL, used by the gst_util_uint64_scale unit test only
+AG_GST_CHECK_LIBHEADER(GMP, gmp,
+                        __gmpz_init_set_d, ,
+                        gmp.h,
+                        GMP_LIBS="-lgmp"
+                        AC_SUBST(GMP_LIBS)
+			AC_DEFINE(HAVE_GMP, [1],[Have GMP library]))
+AG_GST_CHECK_LIBHEADER(GSL, gsl,
+                        gsl_rng_uniform_int, -lgslcblas,
+                        gsl/gsl_rng.h,
+                        GSL_LIBS="-lgsl -lgslcblas"
+                        AC_SUBST(GSL_LIBS)
+			AC_DEFINE(HAVE_GSL, [1],[Have GSL library]))
+
+AC_CHECK_LIB(rt, clock_gettime, [
+  AC_DEFINE(HAVE_CLOCK_GETTIME, 1)
+    LIBS="$LIBS -lrt"
+])
+
 dnl *** checks for types/defines ***
 
 dnl *** checks for structures ***

tests/check/Makefile.am

@@ -143,6 +143,8 @@ LDADD = $(top_builddir)/libs/gst/check/libgstcheck-@GST_MAJORMINOR@.la \
 	$(GST_OBJ_LIBS) \
 	$(CHECK_LIBS)
 
+gst_gstutils_LDADD = $(LDADD) $(GSL_LIBS) $(GMP_LIBS)
+
 libs_gdp_SOURCES = \
 	libs/gdp.c
 libs_gdp_CFLAGS = $(AM_CFLAGS)

tests/check/gst/gstutils.c

@@ -20,6 +20,10 @@
  * Boston, MA 02111-1307, USA.
  */
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include <gst/check/gstcheck.h>
 
 #define SPECIAL_POINTER(x) ((void*)(19283847+(x)))
@@ -738,6 +742,160 @@ GST_START_TEST (test_binary_search)
 
 GST_END_TEST;
 
+#ifdef HAVE_GSL
+#ifdef HAVE_GMP
+
+#include <gsl/gsl_rng.h>
+#include <gmp.h>
+
+static guint64
+randguint64 (gsl_rng * rng, guint64 n)
+{
+  union
+  {
+    guint64 x;
+    struct
+    {
+      guint16 a, b, c, d;
+    } parts;
+  } x;
+  x.parts.a = gsl_rng_uniform_int (rng, 1 << 16);
+  x.parts.b = gsl_rng_uniform_int (rng, 1 << 16);
+  x.parts.c = gsl_rng_uniform_int (rng, 1 << 16);
+  x.parts.d = gsl_rng_uniform_int (rng, 1 << 16);
+  return x.x % n;
+}
+
+
+enum round_t
+{
+  ROUND_TONEAREST = 0,
+  ROUND_UP,
+  ROUND_DOWN
+};
+
+static guint64
+gmp_scale (guint64 x, guint64 a, guint64 b, enum round_t mode)
+{
+  mpz_t mp1, mp2;
+  if (!b)
+    /* overflow */
+    return G_MAXUINT64;
+  mpz_init_set_ui (mp1, x);
+  mpz_init (mp2);
+  mpz_mul_ui (mp2, mp1, a);
+  switch (mode) {
+    case ROUND_TONEAREST:
+      mpz_add_ui (mp1, mp2, b / 2);
+      mpz_set (mp2, mp1);
+      break;
+    case ROUND_UP:
+      mpz_add_ui (mp1, mp2, b - 1);
+      mpz_set (mp2, mp1);
+      break;
+    case ROUND_DOWN:
+      break;
+  }
+  mpz_tdiv_q_ui (mp1, mp2, b);
+  x = mpz_get_ui (mp1);
+  mpz_clear (mp1);
+  mpz_clear (mp2);
+  return x;
+}
+
+static void
+_gmp_test_scale (gsl_rng * rng)
+{
+  guint64 bygst, bygmp;
+  guint64 a = randguint64 (rng, gsl_rng_uniform_int (rng,
+          2) ? G_MAXUINT64 : G_MAXUINT32);
+  guint64 b = randguint64 (rng, gsl_rng_uniform_int (rng, 2) ? G_MAXUINT64 - 1 : G_MAXUINT32 - 1) + 1;  /* 0 not allowed */
+  guint64 val = randguint64 (rng, gmp_scale (G_MAXUINT64, b, a, ROUND_DOWN));
+  enum round_t mode = gsl_rng_uniform_int (rng, 3);
+  const char *func;
+
+  bygmp = gmp_scale (val, a, b, mode);
+  switch (mode) {
+    case ROUND_TONEAREST:
+      bygst = gst_util_uint64_scale_round (val, a, b);
+      func = "gst_util_uint64_scale_round";
+      break;
+    case ROUND_UP:
+      bygst = gst_util_uint64_scale_ceil (val, a, b);
+      func = "gst_util_uint64_scale_ceil";
+      break;
+    case ROUND_DOWN:
+      bygst = gst_util_uint64_scale (val, a, b);
+      func = "gst_util_uint64_scale";
+      break;
+  }
+  fail_unless (bygst == bygmp,
+      "error: %s(): %" G_GUINT64_FORMAT " * %" G_GUINT64_FORMAT " / %"
+      G_GUINT64_FORMAT " = %" G_GUINT64_FORMAT ", correct = %" G_GUINT64_FORMAT
+      "\n", func, val, a, b, bygst, bygmp);
+}
+
+static void
+_gmp_test_scale_int (gsl_rng * rng)
+{
+  guint64 bygst, bygmp;
+  gint32 a = randguint64 (rng, G_MAXINT32);
+  gint32 b = randguint64 (rng, G_MAXINT32 - 1) + 1;     /* 0 not allowed */
+  guint64 val = randguint64 (rng, gmp_scale (G_MAXUINT64, b, a, ROUND_DOWN));
+  enum round_t mode = gsl_rng_uniform_int (rng, 3);
+  const char *func;
+
+  bygmp = gmp_scale (val, a, b, mode);
+  switch (mode) {
+    case ROUND_TONEAREST:
+      bygst = gst_util_uint64_scale_int_round (val, a, b);
+      func = "gst_util_uint64_scale_int_round";
+      break;
+    case ROUND_UP:
+      bygst = gst_util_uint64_scale_int_ceil (val, a, b);
+      func = "gst_util_uint64_scale_int_ceil";
+      break;
+    case ROUND_DOWN:
+      bygst = gst_util_uint64_scale_int (val, a, b);
+      func = "gst_util_uint64_scale_int";
+      break;
+  }
+  fail_unless (bygst == bygmp,
+      "error: %s(): %" G_GUINT64_FORMAT " * %d / %d = %" G_GUINT64_FORMAT
+      ", correct = %" G_GUINT64_FORMAT "\n", func, val, a, b, bygst, bygmp);
+}
+
+#define GMP_TEST_RUNS 100000
+
+GST_START_TEST (test_math_scale_gmp)
+{
+  gsl_rng *rng = gsl_rng_alloc (gsl_rng_mt19937);
+  gint n;
+
+  for (n = 0; n < GMP_TEST_RUNS; n++)
+    _gmp_test_scale (rng);
+
+  gsl_rng_free (rng);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_math_scale_gmp_int)
+{
+  gsl_rng *rng = gsl_rng_alloc (gsl_rng_mt19937);
+  gint n;
+
+  for (n = 0; n < GMP_TEST_RUNS; n++)
+    _gmp_test_scale_int (rng);
+
+  gsl_rng_free (rng);
+}
+
+GST_END_TEST;
+
+#endif
+#endif
+
 static Suite *
 gst_utils_suite (void)
 {
@@ -752,6 +910,13 @@ gst_utils_suite (void)
   tcase_add_test (tc_chain, test_math_scale_ceil);
   tcase_add_test (tc_chain, test_math_scale_uint64);
   tcase_add_test (tc_chain, test_math_scale_random);
+#ifdef HAVE_GSL
+#ifdef HAVE_GMP
+  tcase_add_test (tc_chain, test_math_scale_gmp);
+  tcase_add_test (tc_chain, test_math_scale_gmp_int);
+#endif
+#endif
+
   tcase_add_test (tc_chain, test_guint64_to_gdouble);
   tcase_add_test (tc_chain, test_gdouble_to_guint64);
 #ifndef GST_DISABLE_PARSE