+
+\f
+
+struct casereader_append_numeric
+{
+ int value_ofs;
+ casenumber n;
+ new_value_func *func;
+ void *aux;
+ void (*destroy) (void *aux);
+};
+
+static bool can_destroy (void *can_);
+
+static void can_translate (struct ccase *input, struct ccase *output,
+ void *can_);
+
+/* Creates and returns a new casereader whose cases are produced
+ by reading from SUBREADER and appending an additional value,
+ generated by FUNC. AUX is an optional parameter which
+ gets passed to FUNC. FUNC will also receive N as it, which is
+ the ordinal number of the case in the reader. DESTROY is an
+ optional parameter used to destroy AUX.
+
+ After this function is called, SUBREADER must not ever again
+ be referenced directly. It will be destroyed automatically
+ when the translating casereader is destroyed. */
+struct casereader *
+casereader_create_append_numeric (struct casereader *subreader,
+ new_value_func func, void *aux,
+ void (*destroy) (void *aux))
+{
+ struct casereader_append_numeric *can = xmalloc (sizeof *can);
+ can->value_ofs = casereader_get_value_cnt (subreader);
+ can->n = 0;
+ can->aux = aux;
+ can->func = func;
+ can->destroy = destroy;
+ return casereader_create_translator (subreader, can->value_ofs + 1,
+ can_translate, can_destroy, can);
+}
+
+
+static void
+can_translate (struct ccase *input, struct ccase *output, void *can_)
+{
+ struct casereader_append_numeric *can = can_;
+ double new_value = can->func (input, can->n++, can->aux);
+ case_nullify (output);
+ case_move (output, input);
+ case_resize (output, can->value_ofs + 1);
+ case_data_rw_idx (output, can->value_ofs)->f = new_value;
+}
+
+static bool
+can_destroy (void *can_)
+{
+ struct casereader_append_numeric *can = can_;
+ if (can->destroy)
+ can->destroy (can->aux);
+ free (can);
+ return true;
+}
+
+\f
+
+struct arithmetic_sequence
+{
+ double first;
+ double increment;
+};
+
+static double
+next_arithmetic (const struct ccase *c UNUSED,
+ casenumber n,
+ void *aux)
+{
+ struct arithmetic_sequence *as = aux;
+ return n * as->increment + as->first;
+}
+
+/* Creates and returns a new casereader whose cases are produced
+ by reading from SUBREADER and appending an additional value,
+ which takes the value FIRST in the first case, FIRST +
+ INCREMENT in the second case, FIRST + INCREMENT * 2 in the
+ third case, and so on.
+
+ After this function is called, SUBREADER must not ever again
+ be referenced directly. It will be destroyed automatically
+ when the translating casereader is destroyed. */
+struct casereader *
+casereader_create_arithmetic_sequence (struct casereader *subreader,
+ double first, double increment)
+{
+ struct arithmetic_sequence *as = xzalloc (sizeof *as);
+ as->first = first;
+ as->increment = increment;
+ return casereader_create_append_numeric (subreader, next_arithmetic,
+ as, free);
+}
+
+
+\f
+
+struct casereader_append_rank
+{
+ struct casereader *clone;
+ casenumber n;
+ const struct variable *var;
+ const struct variable *weight;
+ int value_ofs;
+ casenumber n_common;
+ double mean_rank;
+ double cc;
+ distinct_func *distinct;
+ void *aux;
+};
+
+static bool car_destroy (void *car_);
+
+static void car_translate (struct ccase *input, struct ccase *output,
+ void *car_);
+
+/* Creates and returns a new casereader whose cases are produced
+ by reading from SUBREADER and appending an additional value,
+ which is the rank of the observation. SUBREADER must be sorted
+ on V. W is the weight variable of the dictionary containing V,
+ or NULL if there is no weight variable.
+
+ If DISTINCT_CALLBACK is non-null, then it will be called exactly
+ once for every case containing a distinct value of V. AUX is
+ an auxilliary pointer passed to DISTINCT_CALLBACK.
+
+ After this function is called, SUBREADER must not ever again
+ be referenced directly. It will be destroyed automatically
+ when the translating casereader is destroyed. */
+struct casereader *
+casereader_create_append_rank (struct casereader *subreader,
+ const struct variable *v,
+ const struct variable *w,
+ distinct_func *distinct_callback,
+ void *aux
+ )
+{
+ struct casereader_append_rank *car = xmalloc (sizeof *car);
+ car->value_ofs = casereader_get_value_cnt (subreader);
+ car->weight = w;
+ car->var = v;
+ car->n = 0;
+ car->n_common = 1;
+ car->cc = 0.0;
+ car->clone = casereader_clone (subreader);
+ car->distinct = distinct_callback;
+ car->aux = aux;
+
+ return casereader_create_translator (subreader, car->value_ofs + 1,
+ car_translate, car_destroy, car);
+}
+
+
+static bool
+car_destroy (void *car_)
+{
+ struct casereader_append_rank *car = car_;
+ casereader_destroy (car->clone);
+ free (car);
+ return true;
+}
+
+
+static void
+car_translate (struct ccase *input, struct ccase *output, void *car_)
+{
+ struct casereader_append_rank *car = car_;
+
+ double value = case_data (input, car->var)->f;
+
+ if ( car->n_common == 1)
+ {
+ double vxx = SYSMIS;
+ casenumber k = 0;
+ double weight = 1.0;
+ if (car->weight)
+ weight = case_data (input, car->weight)->f;
+
+ do
+ {
+ struct ccase c;
+ if ( ! casereader_peek (car->clone, car->n + ++k, &c))
+ break;
+ vxx = case_data (&c, car->var)->f;
+
+ if ( vxx == value)
+ {
+ if (car->weight)
+ weight += case_data (&c, car->weight)->f;
+ else
+ weight += 1.0;
+ car->n_common++;
+ }
+ case_destroy (&c);
+ }
+ while (vxx == value);
+ car->mean_rank = car->cc + (weight + 1) / 2.0;
+ car->cc += weight;
+
+ if (car->distinct)
+ car->distinct (value, car->n_common, weight, car->aux);
+ }
+ else
+ car->n_common--;
+
+ car->n++;
+
+ case_nullify (output);
+ case_move (output, input);
+ case_resize (output, car->value_ofs + 1);
+ case_data_rw_idx (output, car->value_ofs)->f = car->mean_rank ;
+}
+
+