added the missing examples files;

added a LICENSE (all the C-files are under pd's FreeBSD-like license,
the HOWTO itself is CreativeCommons-ShareAlike 2.5)

svn path=/trunk/; revision=4525

1 files changed, 202 insertions, 0 deletions

diff --git a/doc/tutorials/externals-howto/example3/counter.c b/doc/tutorials/externals-howto/example3/counter.c
new file mode 100644
index 00000000..4eee6a5e
--- /dev/null
+++ b/doc/tutorials/externals-howto/example3/counter.c
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+/*
+ * HOWTO write an External for Pure data
+ * (c) 2001-2006 IOhannes m zmölnig zmoelnig[AT]iem.at
+ *
+ * this is the source-code for the third example in the HOWTO
+ * it creates an object that increments and outputs a counter
+ * whenever it gets banged.
+ * the counter value can be "set" to a special value, or "reset" to a default
+ * an upper and lower boundary can be specified: whenever the counter crosses
+ * such boundary a "bang" is emitted at the 2nd outlet and the counter value wraps
+ *
+ * for legal issues please see the file LICENSE.txt
+ */
+
+
+/**
+ * include the interface to Pd 
+ */
+#include "m_pd.h"
+
+
+/**
+ * define a new "class" 
+ */
+static t_class *counter_class;
+
+
+/**
+ * this is the dataspace of our new object
+ * the first element is the mandatory "t_object"
+ * then we have all sort of variables for the
+ * actual counter value, the step-size and the counting boundaries
+ * finally we have 2 "t_outlet" elements so we can send data
+ * to a "named" outlet.
+ */
+typedef struct _counter {
+  t_object  x_obj;         /* mandatory t_object */
+  t_int i_count;           /* the current counter value */
+  t_float step;            /* step size; 
+                            * this is "float" because of the passive inlet we are using */
+  t_int i_down, i_up;      /* lower and upper boundary */
+  t_outlet *f_out, *b_out; /* outlets */
+} t_counter;
+
+
+/**
+ * this method is called whenever a "bang" is sent to the object
+ */
+void counter_bang(t_counter *x)
+{
+  t_float f=x->i_count;
+  t_int step = x->step;
+  x->i_count+=step;
+
+  if (x->i_down-x->i_up) {
+    if ((step>0) && (x->i_count > x->i_up)) {
+      x->i_count = x->i_down;
+      /* we crossed the upper boundary, so we send a bang out of 
+       * the 2nd outlet (which is x->b_out)
+       */
+      outlet_bang(x->b_out);
+    } else if (x->i_count < x->i_down) {
+      x->i_count = x->i_up;
+      outlet_bang(x->b_out);
+    }
+  }
+  /* output the current counter value at the 1st outlet (which is x->f_out) */
+  outlet_float(x->f_out, f);
+}
+
+
+/**
+ * this is called whenever a "reset" message is sent to the inlet of the object
+ * since the "reset" message has no arguments (as declared in counter_setup())
+ * we only get a reference to the class-dataspace
+ */
+void counter_reset(t_counter *x)
+{
+  x->i_count = x->i_down;
+}
+
+
+/**
+ * this is called whenever a "set" message is sent to the inlet of the object
+ * since the "set" message has one floating-point argument (as declared in counter_setup())
+ * we get a reference to the class-dataspace and the value 
+ */
+void counter_set(t_counter *x, t_floatarg f)
+{
+  x->i_count = f;
+}
+
+
+/**
+ * this is called whenever a "bound" message is sent to the inlet of the object
+ * note that in counter_new(), we rewrite a list to the 2nd inlet 
+ * to a "bound" message to the 1st inlet
+ */
+void counter_bound(t_counter *x, t_floatarg f1, t_floatarg f2)
+{
+  x->i_down = (f1<f2)?f1:f2;
+  x->i_up   = (f1>f2)?f1:f2;
+}
+
+
+/**
+ * this is the "constructor" of the class
+ * we expect a variable number of arguments to this object
+ * symbol "s" is the name of the object itself
+ * the arguments are given as a t_atom array of argc elements.
+ */
+void *counter_new(t_symbol *s, int argc, t_atom *argv)
+{
+  t_counter *x = (t_counter *)pd_new(counter_class);
+  t_float f1=0, f2=0;
+
+  /* depending on the number of arguments we interprete them differently */
+  x->step=1;
+  switch(argc){
+  default:
+  case 3:
+    x->step=atom_getfloat(argv+2);
+  case 2:
+    f2=atom_getfloat(argv+1);
+  case 1:
+    f1=atom_getfloat(argv);
+    break;
+  case 0:
+  }
+  if (argc<2)f2=f1;
+
+  x->i_down = (f1<f2)?f1:f2;
+  x->i_up   = (f1>f2)?f1:f2;
+
+  x->i_count=x->i_down;
+
+  /* create a new active inlet for this object
+   * a message with the selector "list" that is sent
+   * to this inlet (it is the 2nd inlet from left),
+   * will be appear to be the same message but with the selector "bound"
+   * at the 1st inlet.
+   * the method for "bound" messages is given in counter_setup()
+   */
+  inlet_new(&x->x_obj, &x->x_obj.ob_pd,
+        gensym("list"), gensym("bound"));
+
+  /* create a passive inlet inlet (it will be the 2rd inlet from left)
+   * whenever a floating point number is sent to this inlet,
+   * its value will be immediately stored in "x->step"
+   * no function will be called
+   */
+  floatinlet_new(&x->x_obj, &x->step);
+
+  /* create a new outlet which will output floats
+   * we store a reference to this outlet in x->f_out
+   * so we are able to send data to this very outlet
+   */
+  x->f_out = outlet_new(&x->x_obj, &s_float);
+  /* create a new outlet which will output bangs */
+  x->b_out = outlet_new(&x->x_obj, &s_bang);
+
+  return (void *)x;
+}
+
+
+/**
+ * define the function-space of the class
+ */
+void counter_setup(void) {
+  counter_class = class_new(gensym("counter"),
+                            (t_newmethod)counter_new,
+                            0, sizeof(t_counter),
+                            CLASS_DEFAULT, 
+                            A_GIMME, /* an arbitrary number of arguments 
+                                      * which are of arbitrary type */
+                            0);
+
+  /* call a function when a "bang" message appears on the first inlet */
+  class_addbang  (counter_class, counter_bang);
+
+  /* call a function when a "reset" message (without arguments) appears on the first inlet */
+  class_addmethod(counter_class,
+        (t_method)counter_reset, gensym("reset"), 0);
+
+  /* call a function when a "set" message with one float-argument (defaults to 0)
+   * appears on the first inlet */
+  class_addmethod(counter_class, 
+        (t_method)counter_set, gensym("set"),
+        A_DEFFLOAT, 0);
+
+  /* call a function when a "bound" message with 2 float-argument (both default to 0)
+   * appears on the first inlet
+   * this is used for "list" messages which appear on the 2nd inlet
+   * the magic is done in counter_new()
+   */
+  class_addmethod(counter_class,
+        (t_method)counter_bound, gensym("bound"),
+        A_DEFFLOAT, A_DEFFLOAT, 0);
+
+  /* set the name of the help-patch to "help-counter"(.pd) */
+  class_sethelpsymbol(counter_class, gensym("help-counter"));
+}