split excit.c in iterator component files

src/Makefile.am

@@ -2,6 +2,6 @@ AM_CFLAGS = -Wall -Werror -pedantic
 
 lib_LTLIBRARIES = libexcit.la
 
-libexcit_la_SOURCES = excit.c excit.h
+libexcit_la_SOURCES = excit.c slice.c prod.c cons.c repeat.c hilbert2d.c range.c
 
 include_HEADERS = excit.h

src/cons.c

+#include "excit.h"
+#include "dev/excit.h"
+#include "cons.h"
+
+static void circular_fifo_add(struct circular_fifo_s *fifo, ssize_t elem)
+{
+	if (fifo->size == fifo->length) {
+		fifo->start = (fifo->start + 1) % fifo->length;
+		fifo->end = (fifo->end + 1) % fifo->length;
+	} else {
+		fifo->end = (fifo->end + 1) % fifo->length;
+		fifo->size++;
+	}
+	fifo->buffer[fifo->end] = elem;
+}
+
+static void circular_fifo_dump(const struct circular_fifo_s *fifo,
+			       ssize_t * vals)
+{
+	ssize_t i;
+	ssize_t j;
+
+	for (i = 0, j = fifo->start; i < fifo->size; i++) {
+		vals[i] = fifo->buffer[j];
+		j = (j + 1) % fifo->length;
+	}
+}
+
+static int cons_it_alloc(excit_t data)
+{
+	struct cons_it_s *it = (struct cons_it_s *)data->data;
+
+	it->it = NULL;
+	it->n = 0;
+	it->fifo.length = 0;
+	it->fifo.start = 0;
+	it->fifo.end = -1;
+	it->fifo.size = 0;
+	it->fifo.buffer = NULL;
+	return EXCIT_SUCCESS;
+}
+
+static void cons_it_free(excit_t data)
+{
+	struct cons_it_s *it = (struct cons_it_s *)data->data;
+
+	excit_free(it->it);
+	free(it->fifo.buffer);
+}
+
+static int cons_it_copy(excit_t ddst, const excit_t dsrc)
+{
+	struct cons_it_s *dst = (struct cons_it_s *)ddst->data;
+	const struct cons_it_s *src = (const struct cons_it_s *)dsrc->data;
+	excit_t copy = excit_dup(src->it);
+
+	if (!copy)
+		return -EXCIT_EINVAL;
+	dst->it = copy;
+	dst->n = src->n;
+	dst->fifo.length = src->fifo.length;
+	dst->fifo.start = src->fifo.start;
+	dst->fifo.end = src->fifo.end;
+	dst->fifo.size = src->fifo.size;
+	dst->fifo.buffer =
+	    (ssize_t *) malloc(src->fifo.length * sizeof(ssize_t));
+	if (!dst->fifo.buffer) {
+		excit_free(copy);
+		return -EXCIT_ENOMEM;
+	}
+	for (int i = 0; i < dst->fifo.length; i++)
+		dst->fifo.buffer[i] = src->fifo.buffer[i];
+	return EXCIT_SUCCESS;
+}
+
+static int cons_it_size(const excit_t data, ssize_t * size)
+{
+	const struct cons_it_s *it = (const struct cons_it_s *)data->data;
+	ssize_t tmp_size = 0;
+	int err = excit_size(it->it, &tmp_size);
+
+	if (err)
+		return err;
+	*size = tmp_size - (it->n - 1);
+	return EXCIT_SUCCESS;
+}
+
+static int cons_it_split(const excit_t data, ssize_t n, excit_t * results)
+{
+	ssize_t size;
+	int err = cons_it_size(data, &size);
+
+	if (err)
+		return err;
+	if (size < n)
+		return -EXCIT_EDOM;
+	if (!results)
+		return EXCIT_SUCCESS;
+	excit_t range = excit_alloc(EXCIT_RANGE);
+
+	if (!range)
+		return -EXCIT_ENOMEM;
+	err = excit_range_init(range, 0, size - 1, 1);
+	if (err)
+		goto error1;
+	err = excit_split(range, n, results);
+	if (err)
+		goto error1;
+	int i;
+
+	for (i = 0; i < n; i++) {
+		excit_t tmp, tmp2;
+
+		tmp = excit_dup(data);
+		if (!tmp)
+			goto error2;
+		tmp2 = results[i];
+		results[i] = excit_alloc(EXCIT_SLICE);
+		if (!results[i]) {
+			excit_free(tmp2);
+			goto error2;
+		}
+		err = excit_slice_init(results[i], tmp, tmp2);
+		if (err) {
+			excit_free(tmp2);
+			goto error2;
+		}
+	}
+	excit_free(range);
+	return EXCIT_SUCCESS;
+error2:
+	for (; i >= 0; i--)
+		excit_free(results[i]);
+error1:
+	excit_free(range);
+	return err;
+}
+
+static int cons_it_nth(const excit_t data, ssize_t n, ssize_t * indexes)
+{
+	ssize_t size;
+	int err = cons_it_size(data, &size);
+
+	if (err)
+		return err;
+	if (n < 0 || n >= size)
+		return -EXCIT_EDOM;
+	const struct cons_it_s *it = (const struct cons_it_s *)data->data;
+	int dim = it->it->dimension;
+
+	if (indexes) {
+		for (int i = 0; i < it->n; i++) {
+			err = excit_nth(it->it, n + i, indexes + dim * i);
+			if (err)
+				return err;
+		}
+	}
+	return EXCIT_SUCCESS;
+}
+
+static int cons_it_rank(const excit_t data, const ssize_t * indexes,
+			ssize_t * n)
+{
+	const struct cons_it_s *it = (const struct cons_it_s *)data->data;
+	ssize_t inner_n, inner_n_tmp;
+	int err = excit_rank(it->it, indexes, &inner_n);
+
+	if (err)
+		return err;
+	int dim = it->it->dimension;
+
+	for (int i = 1; i < it->n; i++) {
+		err = excit_rank(it->it, indexes + dim * i, &inner_n_tmp);
+		if (err)
+			return err;
+		if (inner_n_tmp != inner_n + 1)
+			return -EXCIT_EINVAL;
+		inner_n = inner_n_tmp;
+	}
+	if (n)
+		*n = inner_n - (it->n - 1);
+	return EXCIT_SUCCESS;
+}
+
+static int cons_it_pos(const excit_t data, ssize_t * n)
+{
+	ssize_t inner_n;
+	const struct cons_it_s *it = (const struct cons_it_s *)data->data;
+	int err = excit_pos(it->it, &inner_n);
+
+	if (err)
+		return err;
+	if (n)
+		*n = inner_n - (it->n - 1);
+	return EXCIT_SUCCESS;
+}
+
+static int cons_it_peek(const excit_t data, ssize_t * indexes)
+{
+	const struct cons_it_s *it = (const struct cons_it_s *)data->data;
+	int err;
+	int dim = it->it->dimension;
+	int n = it->n;
+
+	if (indexes) {
+		circular_fifo_dump(&it->fifo, indexes);
+		err = excit_peek(it->it, indexes + dim * (n - 1));
+	} else
+		err = excit_peek(it->it, NULL);
+	if (err)
+		return err;
+	return EXCIT_SUCCESS;
+}
+
+static int cons_it_next(excit_t data, ssize_t * indexes)
+{
+	struct cons_it_s *it = (struct cons_it_s *)data->data;
+	int err;
+	int dim = it->it->dimension;
+	int n = it->n;
+
+	if (indexes) {
+		circular_fifo_dump(&it->fifo, indexes);
+		err = excit_next(it->it, indexes + dim * (n - 1));
+	} else
+		err = excit_next(it->it, NULL);
+	if (err)
+		return err;
+	if (indexes)
+		for (int i = dim * (n - 1); i < dim * n; i++)
+			circular_fifo_add(&it->fifo, indexes[i]);
+	return EXCIT_SUCCESS;
+}
+
+static int cons_it_rewind(excit_t data)
+{
+	struct cons_it_s *it = (struct cons_it_s *)data->data;
+	int err = excit_rewind(it->it);
+
+	if (err)
+		return err;
+	it->fifo.start = 0;
+	it->fifo.end = -1;
+	it->fifo.size = 0;
+
+	for (int i = 0; i < it->n - 1; i++) {
+		int err;
+
+		err =
+		    excit_next(it->it, it->fifo.buffer + it->it->dimension * i);
+		if (err)
+			return err;
+		it->fifo.size += it->it->dimension;
+		it->fifo.end += it->it->dimension;
+	}
+	return EXCIT_SUCCESS;
+}
+
+int excit_cons_init(excit_t it, excit_t src, ssize_t n)
+{
+	ssize_t src_size;
+	int err;
+
+	if (!it || it->type != EXCIT_CONS || !src || n <= 0)
+		return -EXCIT_EINVAL;
+	err = excit_size(src, &src_size);
+	if (err)
+		return err;
+	if (src_size < n)
+		return -EXCIT_EINVAL;
+	struct cons_it_s *cons_it = (struct cons_it_s *)it->data;
+
+	free(cons_it->fifo.buffer);
+	excit_free(cons_it->it);
+	it->dimension = n * src->dimension;
+	cons_it->it = src;
+	cons_it->n = n;
+	cons_it->fifo.length = src->dimension * (n - 1);
+	cons_it->fifo.buffer =
+	    (ssize_t *) malloc(cons_it->fifo.length * sizeof(ssize_t));
+	if (!cons_it->fifo.buffer)
+		return -EXCIT_ENOMEM;
+	err = cons_it_rewind(it);
+	if (err) {
+		free(cons_it->fifo.buffer);
+		return err;
+	}
+	return EXCIT_SUCCESS;
+}
+
+struct excit_func_table_s excit_cons_func_table = {
+	cons_it_alloc,
+	cons_it_free,
+	cons_it_copy,
+	cons_it_next,
+	cons_it_peek,
+	cons_it_size,
+	cons_it_rewind,
+	cons_it_split,
+	cons_it_nth,
+	cons_it_rank,
+	cons_it_pos
+};

src/cons.h

+#ifndef EXCIT_CONS_H
+#define EXCIT_CONS_H
+
+#include "excit.h"
+#include "dev/excit.h"
+
+struct circular_fifo_s {
+	ssize_t length;
+	ssize_t start;
+	ssize_t end;
+	ssize_t size;
+	ssize_t *buffer;
+};
+
+struct cons_it_s {
+	excit_t it;
+	ssize_t n;
+	struct circular_fifo_s fifo;
+};
+
+extern struct excit_func_table_s excit_cons_func_table;
+
+#endif //EXCIT_CONS_H

src/dev/excit.h

+#ifndef EXCIT_DEV_H
+#define EXCIT_DEV_H
+
+#include "../excit.h"
+
+struct excit_s {
+	struct excit_func_table_s *func_table;
+	ssize_t dimension;
+	enum excit_type_e type;
+	void *data;
+};
+
+#endif
+

src/excit.h

 #ifndef EXCIT_H
 #define EXCIT_H 1
 
+#include <stdlib.h>
+
 /*
  * The different types of iterator supported. All iterators use the same
  * integer type (ssize_t) for values.
  */
 enum excit_type_e {
-	EXCIT_INVALID, /*!< Tag for invalid iterators */
-	EXCIT_RANGE, /*!< Iterator over a range of values */
-	EXCIT_CONS, /*!< Sliding window iterator */
-	EXCIT_REPEAT, /*!< Ierator that stutters a certain amount of times */
-	EXCIT_HILBERT2D, /*!< Hilbert space filing curve */
-	EXCIT_PRODUCT, /*!< Iterator over the catesian product of iterators */
-	EXCIT_SLICE, /*!< Iterator using another iterator to index a third */
-	EXCIT_USER, /*!< User-defined iterator */
-	EXCIT_TYPE_MAX /*!< Guard */
+	EXCIT_INVALID,		/*!< Tag for invalid iterators */
+	EXCIT_RANGE,		/*!< Iterator over a range of values */
+	EXCIT_CONS,		/*!< Sliding window iterator */
+	EXCIT_REPEAT,		/*!< Ierator that stutters a certain amount of times */
+	EXCIT_HILBERT2D,	/*!< Hilbert space filing curve */
+	EXCIT_PRODUCT,		/*!< Iterator over the catesian product of iterators */
+	EXCIT_SLICE,		/*!< Iterator using another iterator to index a third */
+	EXCIT_USER,		/*!< User-defined iterator */
+	EXCIT_TYPE_MAX		/*!< Guard */
 };
 
 /*
  * Returns the string representation of an iterator type.
  */
-const char * excit_type_name(enum excit_type_e type);
+const char *excit_type_name(enum excit_type_e type);
 
 /*
  * The different possible return codes of an excit function.
  */
 enum excit_error_e {
-	EXCIT_SUCCESS, /*!< Sucess */
-	EXCIT_STOPIT, /*!< Iteration space is depleted */
-	EXCIT_ENOMEM, /*!< Out of memory */
-	EXCIT_EINVAL, /*!< Parameter has an invalid value */
-	EXCIT_EDOM, /*!< Parameter is out of possible domain */
-	EXCIT_ENOTSUP, /*!< Operation is not supported */
-	EXCIT_ERROR_MAX /*!< Guard */
+	EXCIT_SUCCESS,		/*!< Sucess */
+	EXCIT_STOPIT,		/*!< Iteration space is depleted */
+	EXCIT_ENOMEM,		/*!< Out of memory */
+	EXCIT_EINVAL,		/*!< Parameter has an invalid value */
+	EXCIT_EDOM,		/*!< Parameter is out of possible domain */
+	EXCIT_ENOTSUP,		/*!< Operation is not supported */
+	EXCIT_ERROR_MAX		/*!< Guard */
 };
 
 /*
  * Returns the string representation of a return code.
  */
-const char * excit_error_name(enum excit_error_e err);
+const char *excit_error_name(enum excit_error_e err);
 
 /*
  * Opaque structure of an iterator
@@ -77,66 +79,66 @@ struct excit_func_table_s {
 	 * allocation, the inner data pointer will already be set.
 	 * Returns EXCIT_SUCCESS or an error code.
 	 */
-	int (*alloc)(excit_t it);
+	int (*alloc) (excit_t it);
 	/*
 	 * This function is called during excit_free. After this function is
 	 * called the iterator and the data will be freed.
 	 */
-	void (*free)(excit_t it);
+	void (*free) (excit_t it);
 	/*
 	 * This funciton is called during excit_dup. It is responsible for
 	 * duplicating the content of the inner data between src_it and dst_it.
 	 * Returns EXCIT_SUCCESS or an error code.
 	 */
-	int (*copy)(excit_t dst_it, const excit_t src_it);
+	int (*copy) (excit_t dst_it, const excit_t src_it);
 	/*
 	 * This function is responsible for implementing the next functionality
 	 * of the iterator.
 	 * Returns EXCIT_SUCCESS, EXCIT_STOPIT or an error code.
 	 */
-	int (*next)(excit_t it, ssize_t *indexes);
+	int (*next) (excit_t it, ssize_t * indexes);
 	/*
 	 * This function is responsible for implementing the peek functionality
 	 * of the iterator.
 	 * Returns EXCIT_SUCCESS, EXCIT_STOPIT or an error code.
 	 */
-	int (*peek)(const excit_t it, ssize_t *indexes);
+	int (*peek) (const excit_t it, ssize_t * indexes);
 	/*
 	 * This function is responsible for implementing the size functionality
 	 * of the iterator.
 	 * Returns EXCIT_SUCCESS or an error code.
 	 */
-	int (*size)(const excit_t it, ssize_t *size);
+	int (*size) (const excit_t it, ssize_t * size);
 	/*
 	 * This function is responsible for implementing the rewind
 	 * functionality of the iterator.
 	 * Returns EXCIT_SUCCESS or an error code.
 	 */
-	int (*rewind)(excit_t it);
+	int (*rewind) (excit_t it);
 	/*
 	 * This function is responsible for implementing the split
 	 * functionality of the iterator.
 	 * Returns EXCIT_SUCCESS or an error code.
 	 */
-	int (*split)(const excit_t it, ssize_t n, excit_t *results);
+	int (*split) (const excit_t it, ssize_t n, excit_t * results);
 	/*
 	 * This function is responsible for implementing the nth functionality
 	 * of the iterator.
 	 * Returns EXCIT_SUCCESS or an error code.
 	 */
-	int (*nth)(const excit_t it, ssize_t n, ssize_t *indexes);
+	int (*nth) (const excit_t it, ssize_t n, ssize_t * indexes);
 	/*
 	 * This function is responsible for implementing the rank functionality
 	 * of the iterator.
 	 * Returns EXCIT_SUCCESS or an error code.
 	 */
-	int (*rank)(const excit_t it, const ssize_t *indexes, ssize_t *n);
+	int (*rank) (const excit_t it, const ssize_t * indexes, ssize_t * n);
 	/*
 	 * This function is responsible for implementing the pos functionality
 	 * of the iterator.
 	 * Returns EXCIT_SUCCESS, EXCIT_STOPIT or an error code.
 	 */
-	int (*pos)(const excit_t it, ssize_t *n);
+	int (*pos) (const excit_t it, ssize_t * n);
 };
 
 /*
@@ -203,7 +205,7 @@ int excit_type(excit_t it, enum excit_type_e *type);
  * "dimension": a pointer where the result will be written.
  * Returns EXCIT_SUCCESS or an error code.
  */
-int excit_dimension(excit_t it, ssize_t *dimension);
+int excit_dimension(excit_t it, ssize_t * dimension);
 
 /*
  * Gets the current element of an iterator and increments it.
@@ -213,7 +215,7 @@ int excit_dimension(excit_t it, ssize_t *dimension);
  * Returns EXCIT_SUCCESS if a valid element was retured or EXCIT_STOPIT if the
  * iterator is depleted or an error code.
  */
-int excit_next(excit_t it, ssize_t *indexes);
+int excit_next(excit_t it, ssize_t * indexes);
 
 /*
  * Gets the current element of an iterator.
@@ -223,7 +225,7 @@ int excit_next(excit_t it, ssize_t *indexes);
  * Returns EXCIT_SUCCESS if a valid element was retured or EXCIT_STOPIT if the
  * iterator is depleted or an error code.
  */
-int excit_peek(const excit_t it, ssize_t *indexes);
+int excit_peek(const excit_t it, ssize_t * indexes);
 
 /*
  * Rewinds an iterator to its initial state.
@@ -238,7 +240,7 @@ int excit_rewind(excit_t it);
  * "size": an pointer to the variable where the result will be stored.
  * Returns EXCIT_SUCCESS or an error code.
  */
-int excit_size(const excit_t it, ssize_t *size);
+int excit_size(const excit_t it, ssize_t * size);
 
 /*
  * Splits an iterator envenly into several suub iterators.
@@ -249,7 +251,7 @@ int excit_size(const excit_t it, ssize_t *size);
  * Returns EXCIT_SUCCESS, -EXCIT_EDOM if the source iterator is too small to be
  * subdivised in the wanted number or an error code.
  */
-int excit_split(const excit_t it, ssize_t n, excit_t *results);
+int excit_split(const excit_t it, ssize_t n, excit_t * results);
 
 /*
  * Gets the nth element of an iterator.
@@ -259,7 +261,7 @@ int excit_split(const excit_t it, ssize_t n, excit_t *results);
  *            iterator, no results is returned if NULL.
  * Returns EXCIT_SUCCESS or an error code.
  */
-int excit_nth(const excit_t it, ssize_t rank, ssize_t *indexes);
+int excit_nth(const excit_t it, ssize_t rank, ssize_t * indexes);
 
 /*
  * Gets the rank of an element of an iterator.
@@ -269,7 +271,7 @@ int excit_nth(const excit_t it, ssize_t rank, ssize_t *indexes);
  *         returned if NULL.
  * Returns EXCIT_SUCCESS or an error code.
  */
-int excit_rank(const excit_t it, const ssize_t *indexes, ssize_t *rank);
+int excit_rank(const excit_t it, const ssize_t * indexes, ssize_t * rank);
 
 /*
  * Gets the position of the iterator.
@@ -279,7 +281,7 @@ int excit_rank(const excit_t it, const ssize_t *indexes, ssize_t *rank);
  * Returns EXCIT_SUCCESS or EXCIT_STOPIT if the iterator is depleted or an error
  * code.
  */
-int excit_pos(const excit_t it, ssize_t *rank);
+int excit_pos(const excit_t it, ssize_t * rank);
 
 /*
  * Increments the iterator.
@@ -297,7 +299,7 @@ int excit_skip(excit_t it);
  *            iterator, no results is returned if NULL.
  * Returns EXCIT_SUCCESS or an error code.
  */
-int excit_cyclic_next(excit_t it, ssize_t *indexes, int *looped);
+int excit_cyclic_next(excit_t it, ssize_t * indexes, int *looped);
 
 /*
  * Initializes a range iterator to iterate from first to last (included) by sep.
@@ -359,7 +361,7 @@ int excit_product_add_copy(excit_t it, excit_t added_it);
  * "count": a pointer to a variable where the result will be stored.
  * Returns EXCIT_SUCCESS or an error code.
  */
-int excit_product_count(const excit_t it, ssize_t *count);
+int excit_product_count(const excit_t it, ssize_t * count);
 
 /*
  * Splits a product iterator along the nth iterator.
@@ -373,7 +375,7 @@ int excit_product_count(const excit_t it, ssize_t *count);
  * be subdivised in the wanted number or an error code.
  */
 int excit_product_split_dim(const excit_t it, ssize_t dim, ssize_t n,
-			    excit_t *results);
+			    excit_t * results);
 
 /*
  * Initializes a slice iterator by giving asrc iterator and an indexer iterator.

src/hilbert2d.c

+#include "dev/excit.h"
+#include "hilbert2d.h"
+
+static void rot(ssize_t n, ssize_t * x, ssize_t * y, ssize_t rx, ssize_t ry)
+{
+	if (ry == 0) {
+		if (rx == 1) {
+			*x = n - 1 - *x;
+			*y = n - 1 - *y;
+		}
+		//Swap x and y
+		ssize_t t = *x;
+
+		*x = *y;
+		*y = t;
+	}
+}
+
+//convert (x,y) to d
+static ssize_t xy2d(ssize_t n, ssize_t x, ssize_t y)
+{
+	ssize_t rx, ry, s, d = 0;
+
+	for (s = n / 2; s > 0; s /= 2) {
+		rx = (x & s) > 0;
+		ry = (y & s) > 0;
+		d += s * s * ((3 * rx) ^ ry);
+		rot(s, &x, &y, rx, ry);
+	}
+	return d;
+}
+
+//convert d to (x,y)
+static void d2xy(ssize_t n, ssize_t d, ssize_t * x, ssize_t * y)
+{
+	ssize_t rx, ry, s, t = d;
+
+	*x = *y = 0;
+	for (s = 1; s < n; s *= 2) {
+		rx = 1 & (t / 2);
+		ry = 1 & (t ^ rx);
+		rot(s, x, y, rx, ry);
+		*x += s * rx;
+		*y += s * ry;
+		t /= 4;
+	}
+}
+
+/* End helper functions */
+
+static int hilbert2d_it_alloc(excit_t data)
+{
+	struct hilbert2d_it_s *it = (struct hilbert2d_it_s *)data->data;
+
+	it->n = 0;
+	it->range_it = NULL;
+	return EXCIT_SUCCESS;
+}
+
+static void hilbert2d_it_free(excit_t data)
+{
+	struct hilbert2d_it_s *it = (struct hilbert2d_it_s *)data->data;
+
+	excit_free(it->range_it);
+}
+
+static int hilbert2d_it_copy(excit_t ddst, const excit_t dsrc)
+{
+	struct hilbert2d_it_s *dst = (struct hilbert2d_it_s *)ddst->data;
+	const struct hilbert2d_it_s *src =
+	    (const struct hilbert2d_it_s *)dsrc->data;
+	excit_t copy = excit_dup(src->range_it);
+
+	if (!copy)
+		return -EXCIT_EINVAL;
+	dst->range_it = copy;
+	dst->n = src->n;
+	return EXCIT_SUCCESS;
+}
+
+static int hilbert2d_it_rewind(excit_t data)
+{
+	struct hilbert2d_it_s *it = (struct hilbert2d_it_s *)data->data;
+
+	return excit_rewind(it->range_it);
+}
+
+static int hilbert2d_it_peek(const excit_t data, ssize_t * val)
+{
+	struct hilbert2d_it_s *it = (struct hilbert2d_it_s *)data->data;
+	ssize_t d;
+	int err;
+
+	err = excit_peek(it->range_it, &d);
+	if (err)
+		return err;
+	if (val)
+		d2xy(it->n, d, val, val + 1);
+	return EXCIT_SUCCESS;
+}
+
+static int hilbert2d_it_next(excit_t data, ssize_t * val)
+{
+	struct hilbert2d_it_s *it = (struct hilbert2d_it_s *)data->data;
+	ssize_t d;
+	int err = excit_next(it->range_it, &d);
+
+	if (err)
+		return err;
+	if (val)
+		d2xy(it->n, d, val, val + 1);
+	return EXCIT_SUCCESS;
+}
+
+static int hilbert2d_it_size(const excit_t data, ssize_t * size)
+{
+	const struct hilbert2d_it_s *it = (struct hilbert2d_it_s *)data->data;
+	return excit_size(it->range_it, size);
+}
+
+static int hilbert2d_it_nth(const excit_t data, ssize_t n, ssize_t * val)
+{
+	ssize_t d;
+	struct hilbert2d_it_s *it = (struct hilbert2d_it_s *)data->data;
+	int err = excit_nth(it->range_it, n, &d);
+
+	if (err)
+		return err;
+	if (val)
+		d2xy(it->n, d, val, val + 1);
+	return EXCIT_SUCCESS;
+}
+
+static int hilbert2d_it_rank(const excit_t data, const ssize_t * indexes,
+			     ssize_t * n)
+{
+	struct hilbert2d_it_s *it = (struct hilbert2d_it_s *)data->data;