patch 8.1.2342: random number generator in Vim script is slowv8.1.2342

Problem:    Random number generator in Vim script is slow.
Solution:   Add rand() and srand(). (Yasuhiro Matsumoto, closes #1277)

1 files changed, 102 insertions, 0 deletions

diff --git a/src/evalfunc.c b/src/evalfunc.c
index 075ef1bf1b..a3e5b3e380 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -169,6 +169,7 @@ static void f_pyeval(typval_T *argvars, typval_T *rettv);
 #if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3)
 static void f_pyxeval(typval_T *argvars, typval_T *rettv);
 #endif
+static void f_rand(typval_T *argvars, typval_T *rettv);
 static void f_range(typval_T *argvars, typval_T *rettv);
 static void f_reg_executing(typval_T *argvars, typval_T *rettv);
 static void f_reg_recording(typval_T *argvars, typval_T *rettv);
@@ -225,6 +226,7 @@ static void f_spellsuggest(typval_T *argvars, typval_T *rettv);
 static void f_split(typval_T *argvars, typval_T *rettv);
 #ifdef FEAT_FLOAT
 static void f_sqrt(typval_T *argvars, typval_T *rettv);
+static void f_srand(typval_T *argvars, typval_T *rettv);
 static void f_str2float(typval_T *argvars, typval_T *rettv);
 #endif
 static void f_str2list(typval_T *argvars, typval_T *rettv);
@@ -634,6 +636,7 @@ static funcentry_T global_functions[] =
 #if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3)
     {"pyxeval",		1, 1, FEARG_1,	  f_pyxeval},
 #endif
+    {"rand",		0, 1, FEARG_1,	  f_rand},
     {"range",		1, 3, FEARG_1,	  f_range},
     {"readdir",		1, 2, FEARG_1,	  f_readdir},
     {"readfile",	1, 3, FEARG_1,	  f_readfile},
@@ -725,6 +728,7 @@ static funcentry_T global_functions[] =
     {"split",		1, 3, FEARG_1,	  f_split},
 #ifdef FEAT_FLOAT
     {"sqrt",		1, 1, FEARG_1,	  f_sqrt},
+    {"srand",		0, 1, FEARG_1,	  f_srand},
 #endif
     {"state",		0, 1, FEARG_1,	  f_state},
 #ifdef FEAT_FLOAT
@@ -5129,6 +5133,79 @@ f_pyxeval(typval_T *argvars, typval_T *rettv)
 #endif
 
 /*
+ * "rand()" function
+ */
+    static void
+f_rand(typval_T *argvars, typval_T *rettv)
+{
+    list_T	*l = NULL;
+    UINT32_T	x, y, z, w, t;
+    static int	rand_seed_initialized = FALSE;
+    static UINT32_T xyzw[4] = {123456789, 362436069, 521288629, 88675123};
+
+#define SHUFFLE_XORSHIFT128 \
+	t = x ^ (x << 11); \
+	x = y; y = z; z = w; \
+	w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
+
+    if (argvars[0].v_type == VAR_UNKNOWN)
+    {
+	// When argument is not given, return random number initialized
+	// statically.
+	if (!rand_seed_initialized)
+	{
+	    xyzw[0] = (varnumber_T)time(NULL);
+	    rand_seed_initialized = TRUE;
+	}
+
+	x = xyzw[0];
+	y = xyzw[1];
+	z = xyzw[2];
+	w = xyzw[3];
+	SHUFFLE_XORSHIFT128;
+	xyzw[0] = x;
+	xyzw[1] = y;
+	xyzw[2] = z;
+	xyzw[3] = w;
+    }
+    else if (argvars[0].v_type == VAR_LIST)
+    {
+	listitem_T	*lx, *ly, *lz, *lw;
+
+	l = argvars[0].vval.v_list;
+	if (list_len(l) != 4)
+	    goto theend;
+
+	lx = list_find(l, 0L);
+	ly = list_find(l, 1L);
+	lz = list_find(l, 2L);
+	lw = list_find(l, 3L);
+	if (lx->li_tv.v_type != VAR_NUMBER) goto theend;
+	if (ly->li_tv.v_type != VAR_NUMBER) goto theend;
+	if (lz->li_tv.v_type != VAR_NUMBER) goto theend;
+	if (lw->li_tv.v_type != VAR_NUMBER) goto theend;
+	x = (UINT32_T)lx->li_tv.vval.v_number;
+	y = (UINT32_T)ly->li_tv.vval.v_number;
+	z = (UINT32_T)lz->li_tv.vval.v_number;
+	w = (UINT32_T)lw->li_tv.vval.v_number;
+	SHUFFLE_XORSHIFT128;
+	lx->li_tv.vval.v_number = (varnumber_T)x;
+	ly->li_tv.vval.v_number = (varnumber_T)y;
+	lz->li_tv.vval.v_number = (varnumber_T)z;
+	lw->li_tv.vval.v_number = (varnumber_T)w;
+    }
+    else
+	goto theend;
+
+    rettv->v_type = VAR_NUMBER;
+    rettv->vval.v_number = (varnumber_T)w;
+    return;
+
+theend:
+    semsg(_(e_invarg2), tv_get_string(&argvars[0]));
+}
+
+/*
  * "range()" function
  */
     static void
@@ -7013,6 +7090,31 @@ f_sqrt(typval_T *argvars, typval_T *rettv)
 }
 
 /*
+ * "srand()" function
+ */
+    static void
+f_srand(typval_T *argvars, typval_T *rettv)
+{
+    if (rettv_list_alloc(rettv) == FAIL)
+	return;
+    if (argvars[0].v_type == VAR_UNKNOWN)
+	list_append_number(rettv->vval.v_list, (varnumber_T)vim_time());
+    else
+    {
+	int	    error = FALSE;
+	UINT32_T    x = (UINT32_T)tv_get_number_chk(&argvars[0], &error);
+
+	if (error)
+	    return;
+
+	list_append_number(rettv->vval.v_list, x);
+    }
+    list_append_number(rettv->vval.v_list, 362436069);
+    list_append_number(rettv->vval.v_list, 521288629);
+    list_append_number(rettv->vval.v_list, 88675123);
+}
+
+/*
  * "str2float()" function
  */
     static void