1 files changed, 99 insertions, 0 deletions
diff --git a/src/blockswap~.c b/src/blockswap~.c
new file mode 100644
index 0000000..7dbe99d
--- /dev/null
+++ b/src/blockswap~.c
@@ -0,0 +1,99 @@
+/******************************************************
+ *
+ * zexy - implementation file
+ *
+ * copyleft (c) IOhannes m zmölnig
+ *
+ *   1999:forum::für::umläute:2004
+ *
+ *   institute of electronic music and acoustics (iem)
+ *
+ ******************************************************
+ *
+ * license: GNU General Public License v.2
+ *
+ ******************************************************/
+
+#include "zexy.h"
+
+/* ------------------------ blockswap~ ----------------------------- */
+
+/* swaps a signalblock around it's center:
+   {x[0], x[1], ... x[n-1]} --> {x[n-1], x[n-2], ... x[0]}
+*/
+
+static t_class *blockswap_class;
+
+typedef struct _blockswap
+{
+  t_object x_obj;
+  int doit;
+  int blocksize;
+  t_float *blockbuffer;
+} t_blockswap;
+
+static void blockswap_float(t_blockswap *x, t_floatarg f)
+{
+  x->doit = (f != 0);
+}
+
+static t_int *blockswap_perform(t_int *w)
+{
+  t_blockswap	*x = (t_blockswap *)(w[1]);
+  t_float *in = (t_float *)(w[2]);
+  t_float *out = (t_float *)(w[3]);
+  int N = (int)(w[4]);
+  int N2=N/2;
+  if (x->doit) {
+    int n=N2;
+    t_float *dummy=x->blockbuffer;
+    while(n--)*dummy++=*in++;
+    n=N-N2;
+    while(n--)*out++=*in++;
+    dummy=x->blockbuffer;
+    n=N2;    
+    while(n--)*out++=*dummy++;
+  } else while (N--) *out++=*in++;
+  return (w+5);
+}
+
+static void blockswap_dsp(t_blockswap *x, t_signal **sp)
+{
+  if (x->blocksize*2<sp[0]->s_n){
+    if(x->blockbuffer)freebytes(x->blockbuffer, sizeof(t_float)*x->blocksize);
+    x->blocksize = sp[0]->s_n/2;
+    x->blockbuffer = getbytes(sizeof(t_float)*x->blocksize);
+  }
+  dsp_add(blockswap_perform, 4, x, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
+}
+
+static void blockswap_helper(void)
+{
+  post("\n%c blockswap~-object for blockwise-swapping of a signal ", HEARTSYMBOL);
+  post("'help' : view this\n"
+       "signal~");
+  post("outlet : signal~");
+}
+
+static void *blockswap_new(void)
+{
+  t_blockswap *x = (t_blockswap *)pd_new(blockswap_class);
+  outlet_new(&x->x_obj, gensym("signal"));
+  x->doit = 1;
+  x->blocksize=0;
+  return (x);
+}
+
+void blockswap_tilde_setup(void)
+{
+  blockswap_class = class_new(gensym("blockswap~"), (t_newmethod)blockswap_new, 0,
+			 sizeof(t_blockswap), 0, A_NULL);
+  class_addmethod(blockswap_class, nullfn, gensym("signal"), 0);
+  class_addmethod(blockswap_class, (t_method)blockswap_dsp, gensym("dsp"), 0);
+  
+  class_addfloat(blockswap_class, blockswap_float);
+  
+  class_addmethod(blockswap_class, (t_method)blockswap_helper, gensym("help"), 0);
+  class_sethelpsymbol(blockswap_class, gensym("zexy/blockswap~"));
+  zexy_register("blockswap~");
+}