From 5db0b4008f30da3c416efbb36eb17174332b69b9 Mon Sep 17 00:00:00 2001
From: Cyrille Henry <nusmuk@users.sourceforge.net>
Date: Tue, 10 Jun 2008 08:59:57 +0000
Subject: replacement for tabread4~ and tabosc4~ with a better cubic
 interpolation

svn path=/trunk/externals/nusmuk/; revision=9979
---
 tab/tabread4c~.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 tab/tabread4c~.c

(limited to 'tab/tabread4c~.c')

diff --git a/tab/tabread4c~.c b/tab/tabread4c~.c
new file mode 100644
index 0000000..00da57a
--- /dev/null
+++ b/tab/tabread4c~.c
@@ -0,0 +1,137 @@
+// GPL
+// most of this code comes from pd. just the interpolation shematic is diferent.
+
+#include "m_pd.h"
+
+/******************** tabread4c~ ***********************/
+
+static t_class *tabread4c_tilde_class;
+
+typedef struct _tabread4c_tilde
+{
+    t_object x_obj;
+    int x_npoints;
+    t_word *x_vec;
+    t_symbol *x_arrayname;
+    t_float x_f;
+} t_tabread4c_tilde;
+
+static void *tabread4c_tilde_new(t_symbol *s)
+{
+    t_tabread4c_tilde *x = (t_tabread4c_tilde *)pd_new(tabread4c_tilde_class);
+    x->x_arrayname = s;
+    x->x_vec = 0;
+    outlet_new(&x->x_obj, gensym("signal"));
+    x->x_f = 0;
+    return (x);
+}
+
+static t_int *tabread4c_tilde_perform(t_int *w)
+{
+    t_tabread4c_tilde *x = (t_tabread4c_tilde *)(w[1]);
+    t_sample *in = (t_sample *)(w[2]);
+    t_sample *out = (t_sample *)(w[3]);
+    int n = (int)(w[4]);    
+    int maxindex;
+    t_word *buf = x->x_vec, *wp;
+    int i;
+    double a0,a1,a2; // CH
+    
+    maxindex = x->x_npoints - 3;
+
+    if (!buf) goto zero;
+
+#if 0       /* test for spam -- I'm not ready to deal with this */
+    for (i = 0,  xmax = 0, xmin = maxindex,  fp = in1; i < n; i++,  fp++)
+    {
+        t_sample f = *in1;
+        if (f < xmin) xmin = f;
+        else if (f > xmax) xmax = f;
+    }
+    if (xmax < xmin + x->c_maxextent) xmax = xmin + x->c_maxextent;
+    for (i = 0, splitlo = xmin+ x->c_maxextent, splithi = xmax - x->c_maxextent,
+        fp = in1; i < n; i++,  fp++)
+    {
+        t_sample f = *in1;
+        if (f > splitlo && f < splithi) goto zero;
+    }
+#endif
+
+    for (i = 0; i < n; i++)
+    {
+        t_sample findex = *in++;
+        int index = findex;
+        t_sample frac,  a,  b,  c,  d, cminusb;
+        static int count;
+        if (index < 1)
+            index = 1, frac = 0;
+        else if (index > maxindex)
+            index = maxindex, frac = 1;
+        else frac = findex - index;
+        wp = buf + index;
+        a = wp[-1].w_float;
+        b = wp[0].w_float;
+        c = wp[1].w_float;
+        d = wp[2].w_float;
+        /* if (!i && !(count++ & 1023))
+            post("fp = %lx,  shit = %lx,  b = %f",  fp, buf->b_shit,  b); */
+//        cminusb = c-b;
+//        *out++ = b + frac * (
+//            cminusb - 0.1666667f * (1.-frac) * (
+//                (d - a - 3.0f * cminusb) * frac + (d + 2.0f*a - 3.0f*b)
+// CH
+		a0 = d - c - a + b;
+		a1 = a - b - a0;
+		a2 = c - a;
+		*out++ = ((a0*frac+a1)*frac+a2)*frac+b;       
+    }
+    return (w+5);
+ zero:
+    while (n--) *out++ = 0;
+
+    return (w+5);
+}
+
+void tabread4c_tilde_set(t_tabread4c_tilde *x, t_symbol *s)
+{
+    t_garray *a;
+    
+    x->x_arrayname = s;
+    if (!(a = (t_garray *)pd_findbyclass(x->x_arrayname, garray_class)))
+    {
+        if (*s->s_name)
+            pd_error(x, "tabread4c~: %s: no such array", x->x_arrayname->s_name);
+        x->x_vec = 0;
+    }
+    else if (!garray_getfloatwords(a, &x->x_npoints, &x->x_vec))
+    {
+        pd_error(x, "%s: bad template for tabread4c~", x->x_arrayname->s_name);
+        x->x_vec = 0;
+    }
+    else garray_usedindsp(a);
+}
+
+static void tabread4c_tilde_dsp(t_tabread4c_tilde *x, t_signal **sp)
+{
+    tabread4c_tilde_set(x, x->x_arrayname);
+
+    dsp_add(tabread4c_tilde_perform, 4, x,
+        sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
+
+}
+
+static void tabread4c_tilde_free(t_tabread4c_tilde *x)
+{
+}
+
+void tabread4c_tilde_setup(void)
+{
+    tabread4c_tilde_class = class_new(gensym("tabread4c~"),
+        (t_newmethod)tabread4c_tilde_new, (t_method)tabread4c_tilde_free,
+        sizeof(t_tabread4c_tilde), 0, A_DEFSYM, 0);
+    CLASS_MAINSIGNALIN(tabread4c_tilde_class, t_tabread4c_tilde, x_f);
+    class_addmethod(tabread4c_tilde_class, (t_method)tabread4c_tilde_dsp,
+        gensym("dsp"), 0);
+    class_addmethod(tabread4c_tilde_class, (t_method)tabread4c_tilde_set,
+        gensym("set"), A_SYMBOL, 0);
+}
-- 
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