move invert and shift into common function

src/zlfo.c

@@ -536,52 +536,11 @@ run (
 
       /* invert horizontally */
       long shifted_current_sample =
-        self->common.current_sample;
-      if (*self->hinvert >= 0.01f)
-        {
-          shifted_current_sample =
-            self->common.period_size -
-            self->common.current_sample;
-          if (shifted_current_sample ==
-                self->common.period_size)
-            shifted_current_sample = 0;
-        }
-
-      /* shift */
-      if (*self->shift >= 0.5f)
-        {
-          /* add the samples to shift from 0 to
-           * (half the period width) */
-          shifted_current_sample +=
-            (long)
-            /* shift ratio */
-            (((*self->shift - 0.5f) * 2.f) *
-            /* half a period */
-            (self->common.period_size / 2.f));
-
-          /* readjust */
-          shifted_current_sample =
-            shifted_current_sample %
-              self->common.period_size;
-        }
-      else
-        {
-          /* subtract the samples to shift between
-           * 0 and (half the period width) */
-          shifted_current_sample -=
-            (long)
-            /* shift ratio */
-            (((0.5f - *self->shift) * 2.f) *
-            /* half a period */
-            (self->common.period_size / 2.f));
-
-          /* readjust */
-          while (shifted_current_sample < 0)
-            {
-              shifted_current_sample +=
-                self->common.period_size;
-            }
-        }
+        invert_and_shift_xval (
+          self->common.current_sample,
+          self->common.period_size,
+          *self->hinvert >= 0.01f,
+          *self->shift);
 
       if (IS_STEP_MODE (self))
         {

src/zlfo_math.h

@@ -369,4 +369,57 @@ recalc_vars (
     }
 }
 
+static inline long
+invert_and_shift_xval (
+  long    base,
+  long    max_val,
+  int     hinvert,
+  float   shift)
+{
+  long ret = base;
+
+  /* invert horizontally */
+  if (hinvert)
+    {
+      ret = max_val - ret;
+      while (ret >= max_val)
+        ret -= max_val;
+    }
+
+  /* shift */
+  if (shift >= 0.5f)
+    {
+      /* add the samples to shift from 0 to
+       * (half the period width) */
+      ret +=
+        (long)
+        /* shift ratio */
+        (((shift - 0.5f) * 2.f) *
+        /* half a period */
+        (max_val / 2.f));
+
+      /* readjust */
+      ret = ret % max_val;
+    }
+  else
+    {
+      /* subtract the samples to shift between
+       * 0 and (half the period width) */
+      ret -=
+        (long)
+        /* shift ratio */
+        (((0.5f - shift) * 2.f) *
+        /* half a period */
+        (max_val / 2.f));
+
+      /* readjust */
+      while (ret < 0)
+        {
+          ret += max_val;
+        }
+    }
+
+  return ret;
+}
+
 #endif

src/zlfo_ui.c

@@ -1365,45 +1365,14 @@ draw_graph (
   while (idouble < GRID_WIDTH - 0.01)
     {
       /* from 0 to GRID_WIDTH */
-      double xval = (double) i;
+      long xvall = (long) i;
+      double xvald = (double) i;
 
-      /* invert horizontally */
-      if (self->hinvert)
-        {
-          xval = (double) (GRID_WIDTH - i);
-        }
-
-      /* shift */
-      if (self->shift >= 0.5f)
-        {
-          xval +=
-            /* shift ratio */
-            (((double) self->shift - 0.50) *
-               2.0) *
-             /* half the period */
-            (GRID_WIDTH / 2.0);
-
-          /* adjust */
-          while (xval >= GRID_WIDTH)
-            {
-              xval -= GRID_WIDTH;
-            }
-        }
-      else
-        {
-          xval -=
-            /* shift ratio */
-            ((0.50 - (double) self->shift) *
-               2.0) *
-            /* half a period */
-            (GRID_WIDTH / 2.0);
-
-          /* adjust */
-          while (xval < 0.0)
-            {
-              xval += GRID_WIDTH;
-            }
-        }
+      xvall =
+        invert_and_shift_xval (
+          i, GRID_WIDTH, self->hinvert,
+          self->shift);
+      xvald = (double) xvall;
 
 #define DRAW_VAL(val) \
   /* invert vertically */ \
@@ -1455,10 +1424,12 @@ draw_graph (
   prev_draw_##val = draw_val
 
       /* calculate sine */
-      double sine = (double) self->sine_cache[(int) xval];
+      double sine =
+        (double) self->sine_cache[xvall];
 
       /* calculate saw */
-      double saw = (double) self->saw_cache[(int) xval];
+      double saw =
+        (double) self->saw_cache[xvall];
 
       /* triangle can be calculated based on the
        * saw */
@@ -1473,14 +1444,13 @@ draw_graph (
       /* square too */
       double square = saw < 0.0 ? -1.0 : 1.0;
 
-      /* get prev and next nodes to calculate
-       * custom */
+      double ratio = xvald / GRID_WIDTH;
       int prev_idx =
         get_prev_idx (
-          self, node_indices, xval / GRID_WIDTH);
+          self, node_indices, ratio);
       int next_idx =
         get_next_idx (
-          self, node_indices, xval / GRID_WIDTH);
+          self, node_indices, ratio);
 
       /* calculate custom */
       double custom =
@@ -1497,7 +1467,7 @@ draw_graph (
           next_idx < 0 ?
             self->nodes[0][2] :
             self->nodes[next_idx][2],
-          (float) xval, GRID_WIDTH);
+          (float) xvald, GRID_WIDTH);
 
       /* adjust for -1 to 1 */
       custom = custom * 2 - 1;