/* GLIB - Library of useful routines for C programming

 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free

 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

/*

 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS

 * file for a list of people on the GLib Team.  See the ChangeLog

 * files for a list of changes.  These files are distributed with

 * GLib at ftp://ftp.gtk.org/pub/gtk/. 

 */

/* 

 * MT safe

 */

#include "config.h"

/* we know we are deprecated here, no need for warnings */

#define GLIB_DISABLE_DEPRECATION_WARNINGS

#include "grel.h"

#include <glib/gmessages.h>

#include <glib/gtestutils.h>

#include <glib/gstring.h>

#include <glib/gslice.h>

#include <glib/ghash.h>

#include <stdarg.h>

#include <string.h>

/**

 * SECTION:relations

 * @title: Relations and Tuples

 * @short_description: tables of data which can be indexed on any

 *                     number of fields

 *

 * A #GRelation is a table of data which can be indexed on any number

 * of fields, rather like simple database tables. A #GRelation contains

 * a number of records, called tuples. Each record contains a number of

 * fields. Records are not ordered, so it is not possible to find the

 * record at a particular index.

 *

 * Note that #GRelation tables are currently limited to 2 fields.

 *

 * To create a GRelation, use g_relation_new().

 *

 * To specify which fields should be indexed, use g_relation_index().

 * Note that this must be called before any tuples are added to the

 * #GRelation.

 *

 * To add records to a #GRelation use g_relation_insert().

 *

 * To determine if a given record appears in a #GRelation, use

 * g_relation_exists(). Note that fields are compared directly, so

 * pointers must point to the exact same position (i.e. different

 * copies of the same string will not match.)

 *

 * To count the number of records which have a particular value in a

 * given field, use g_relation_count().

 *

 * To get all the records which have a particular value in a given

 * field, use g_relation_select(). To access fields of the resulting

 * records, use g_tuples_index(). To free the resulting records use

 * g_tuples_destroy().

 *

 * To delete all records which have a particular value in a given

 * field, use g_relation_delete().

 *

 * To destroy the #GRelation, use g_relation_destroy().

 *

 * To help debug #GRelation objects, use g_relation_print().

 *

 * GRelation has been marked as deprecated, since this API has never

 * been fully implemented, is not very actively maintained and rarely

 * used.

 **/

typedef struct _GRealTuples        GRealTuples;

/**

 * GRelation:

 *

 * The #GRelation struct is an opaque data structure to represent a

 * [Relation][glib-Relations-and-Tuples]. It should

 * only be accessed via the following functions.

 **/

struct _GRelation

{

  gint fields;

  gint current_field;

  GHashTable   *all_tuples;

  GHashTable  **hashed_tuple_tables;

  gint count;

};

/**

 * GTuples:

 * @len: the number of records that matched.

 *

 * The #GTuples struct is used to return records (or tuples) from the

 * #GRelation by g_relation_select(). It only contains one public

 * member - the number of records that matched. To access the matched

 * records, you must use g_tuples_index().

 **/

struct _GRealTuples

{

  gint      len;

  gint      width;

  gpointer *data;

};

static gboolean

tuple_equal_2 (gconstpointer v_a,

	       gconstpointer v_b)

{

  gpointer* a = (gpointer*) v_a;

  gpointer* b = (gpointer*) v_b;

  return a[0] == b[0] && a[1] == b[1];

}

static guint

tuple_hash_2 (gconstpointer v_a)

{

#if GLIB_SIZEOF_VOID_P > GLIB_SIZEOF_LONG

  /* In practise this snippet has been written for 64-bit Windows

   * where ints are 32 bits, pointers 64 bits. More exotic platforms

   * need more tweaks.

   */

  guint* a = (guint*) v_a;

  return (a[0] ^ a[1] ^ a[2] ^ a[3]);

#else

  gpointer* a = (gpointer*) v_a;

  return (gulong)a[0] ^ (gulong)a[1];

#endif

}

static GHashFunc

tuple_hash (gint fields)

{

  switch (fields)

    {

    case 2:

      return tuple_hash_2;

    default:

      g_error ("no tuple hash for %d", fields);

    }

  return NULL;

}

static GEqualFunc

tuple_equal (gint fields)

{

  switch (fields)

    {

    case 2:

      return tuple_equal_2;

    default:

      g_error ("no tuple equal for %d", fields);

    }

  return NULL;

}

/**

 * g_relation_new:

 * @fields: the number of fields.

 *

 * Creates a new #GRelation with the given number of fields. Note that

 * currently the number of fields must be 2.

 *

 * Returns: a new #GRelation.

 *

 * Deprecated: 2.26: Rarely used API

 **/

GRelation*

g_relation_new (gint fields)

{

  GRelation* rel = g_new0 (GRelation, 1);

  rel->fields = fields;

  rel->all_tuples = g_hash_table_new (tuple_hash (fields), tuple_equal (fields));

  rel->hashed_tuple_tables = g_new0 (GHashTable*, fields);

  return rel;

}

static void

relation_delete_value_tuple (gpointer tuple_key,

                             gpointer tuple_value,

                             gpointer user_data)

{

  GRelation *relation = user_data;

  gpointer *tuple = tuple_value;

  g_slice_free1 (relation->fields * sizeof (gpointer), tuple);

}

static void

g_relation_free_array (gpointer key, gpointer value, gpointer user_data)

{

  g_hash_table_destroy ((GHashTable*) value);

}

/**

 * g_relation_destroy:

 * @relation: a #GRelation.

 *

 * Destroys the #GRelation, freeing all memory allocated. However, it

 * does not free memory allocated for the tuple data, so you should

 * free that first if appropriate.

 *

 * Deprecated: 2.26: Rarely used API

 **/

void

g_relation_destroy (GRelation *relation)

{

  gint i;

  if (relation)

    {

      for (i = 0; i < relation->fields; i += 1)

	{

	  if (relation->hashed_tuple_tables[i])

	    {

	      g_hash_table_foreach (relation->hashed_tuple_tables[i], g_relation_free_array, NULL);

	      g_hash_table_destroy (relation->hashed_tuple_tables[i]);

	    }

	}

      g_hash_table_foreach (relation->all_tuples, relation_delete_value_tuple, relation);

      g_hash_table_destroy (relation->all_tuples);

      g_free (relation->hashed_tuple_tables);

      g_free (relation);

    }

}

/**

 * g_relation_index:

 * @relation: a #GRelation.

 * @field: the field to index, counting from 0.

 * @hash_func: a function to produce a hash value from the field data.

 * @key_equal_func: a function to compare two values of the given field.

 *

 * Creates an index on the given field. Note that this must be called

 * before any records are added to the #GRelation.

 *

 * Deprecated: 2.26: Rarely used API

 **/

void

g_relation_index (GRelation   *relation,

		  gint         field,

		  GHashFunc    hash_func,

		  GEqualFunc   key_equal_func)

{

  g_return_if_fail (relation != NULL);

  g_return_if_fail (relation->count == 0 && relation->hashed_tuple_tables[field] == NULL);

  relation->hashed_tuple_tables[field] = g_hash_table_new (hash_func, key_equal_func);

}

/**

 * g_relation_insert:

 * @relation: a #GRelation.

 * @...: the fields of the record to add. These must match the

 *       number of fields in the #GRelation, and of type #gpointer

 *       or #gconstpointer.

 *

 * Inserts a record into a #GRelation.

 *

 * Deprecated: 2.26: Rarely used API

 **/

void

g_relation_insert (GRelation   *relation,

		   ...)

{

  gpointer* tuple = g_slice_alloc (relation->fields * sizeof (gpointer));

  va_list args;

  gint i;

  va_start (args, relation);

  for (i = 0; i < relation->fields; i += 1)

    tuple[i] = va_arg (args, gpointer);

  va_end (args);

  g_hash_table_insert (relation->all_tuples, tuple, tuple);

  relation->count += 1;

  for (i = 0; i < relation->fields; i += 1)

    {

      GHashTable *table;

      gpointer    key;

      GHashTable *per_key_table;

      table = relation->hashed_tuple_tables[i];

      if (table == NULL)

	continue;

      key = tuple[i];

      per_key_table = g_hash_table_lookup (table, key);

      if (per_key_table == NULL)

	{

	  per_key_table = g_hash_table_new (tuple_hash (relation->fields), tuple_equal (relation->fields));

	  g_hash_table_insert (table, key, per_key_table);

	}

      g_hash_table_insert (per_key_table, tuple, tuple);

    }

}

static void

g_relation_delete_tuple (gpointer tuple_key,

			 gpointer tuple_value,

			 gpointer user_data)

{

  gpointer      *tuple = (gpointer*) tuple_value;

  GRelation     *relation = (GRelation *) user_data;

  gint           j;

  g_assert (tuple_key == tuple_value);

  for (j = 0; j < relation->fields; j += 1)

    {

      GHashTable *one_table = relation->hashed_tuple_tables[j];

      gpointer    one_key;

      GHashTable *per_key_table;

      if (one_table == NULL)

	continue;

      if (j == relation->current_field)

	/* can't delete from the table we're foreaching in */

	continue;

      one_key = tuple[j];

      per_key_table = g_hash_table_lookup (one_table, one_key);

      g_hash_table_remove (per_key_table, tuple);

    }

  if (g_hash_table_remove (relation->all_tuples, tuple))

    g_slice_free1 (relation->fields * sizeof (gpointer), tuple);

  relation->count -= 1;

}

/**

 * g_relation_delete:

 * @relation: a #GRelation.

 * @key: the value to compare with.

 * @field: the field of each record to match.

 *

 * Deletes any records from a #GRelation that have the given key value

 * in the given field.

 *

 * Returns: the number of records deleted.

 *

 * Deprecated: 2.26: Rarely used API

 **/

gint

g_relation_delete  (GRelation     *relation,

		    gconstpointer  key,

		    gint           field)

{

  GHashTable *table; 

  GHashTable *key_table;

  gint        count;

  g_return_val_if_fail (relation != NULL, 0);

  table = relation->hashed_tuple_tables[field];

  count = relation->count;

  g_return_val_if_fail (table != NULL, 0);

  key_table = g_hash_table_lookup (table, key);

  if (!key_table)

    return 0;

  relation->current_field = field;

  g_hash_table_foreach (key_table, g_relation_delete_tuple, relation);

  g_hash_table_remove (table, key);

  g_hash_table_destroy (key_table);

  /* @@@ FIXME: Remove empty hash tables. */

  return count - relation->count;

}

static void

g_relation_select_tuple (gpointer tuple_key,

			 gpointer tuple_value,

			 gpointer user_data)

{

  gpointer    *tuple = (gpointer*) tuple_value;

  GRealTuples *tuples = (GRealTuples*) user_data;

  gint stride = sizeof (gpointer) * tuples->width;

  g_assert (tuple_key == tuple_value);

  memcpy (tuples->data + (tuples->len * tuples->width),

	  tuple,

	  stride);

  tuples->len += 1;

}

/**

 * g_relation_select:

 * @relation: a #GRelation.

 * @key: the value to compare with.

 * @field: the field of each record to match.

 *

 * Returns all of the tuples which have the given key in the given

 * field. Use g_tuples_index() to access the returned records. The

 * returned records should be freed with g_tuples_destroy().

 *

 * Returns: the records (tuples) that matched.

 *

 * Deprecated: 2.26: Rarely used API

 **/

GTuples*

g_relation_select (GRelation     *relation,

		   gconstpointer  key,

		   gint           field)

{

  GHashTable  *table;

  GHashTable  *key_table;

  GRealTuples *tuples; 

  gint count;

  g_return_val_if_fail (relation != NULL, NULL);

  table = relation->hashed_tuple_tables[field];

  g_return_val_if_fail (table != NULL, NULL);

  tuples = g_new0 (GRealTuples, 1);

  key_table = g_hash_table_lookup (table, key);

  if (!key_table)

    return (GTuples*)tuples;

  count = g_relation_count (relation, key, field);

  tuples->data = g_malloc (sizeof (gpointer) * relation->fields * count);

  tuples->width = relation->fields;

  g_hash_table_foreach (key_table, g_relation_select_tuple, tuples);

  g_assert (count == tuples->len);

  return (GTuples*)tuples;

}

/**

 * g_relation_count:

 * @relation: a #GRelation.

 * @key: the value to compare with.

 * @field: the field of each record to match.

 *

 * Returns the number of tuples in a #GRelation that have the given

 * value in the given field.

 *

 * Returns: the number of matches.

 *

 * Deprecated: 2.26: Rarely used API

 **/

gint

g_relation_count (GRelation     *relation,

		  gconstpointer  key,

		  gint           field)

{

  GHashTable  *table;

  GHashTable  *key_table;

  g_return_val_if_fail (relation != NULL, 0);

  table = relation->hashed_tuple_tables[field];

  g_return_val_if_fail (table != NULL, 0);

  key_table = g_hash_table_lookup (table, key);

  if (!key_table)

    return 0;

  return g_hash_table_size (key_table);

}

/**

 * g_relation_exists:

 * @relation: a #GRelation.

 * @...: the fields of the record to compare. The number must match

 *       the number of fields in the #GRelation.

 *

 * Returns %TRUE if a record with the given values exists in a

 * #GRelation. Note that the values are compared directly, so that, for

 * example, two copies of the same string will not match.

 *

 * Returns: %TRUE if a record matches.

 *

 * Deprecated: 2.26: Rarely used API

 **/

gboolean

g_relation_exists (GRelation   *relation, ...)

{

  gpointer *tuple = g_slice_alloc (relation->fields * sizeof (gpointer));

  va_list args;

  gint i;

  gboolean result;

  va_start(args, relation);

  for (i = 0; i < relation->fields; i += 1)

    tuple[i] = va_arg(args, gpointer);

  va_end(args);

  result = g_hash_table_lookup (relation->all_tuples, tuple) != NULL;

  g_slice_free1 (relation->fields * sizeof (gpointer), tuple);

  return result;

}

/**

 * g_tuples_destroy:

 * @tuples: the tuple data to free.

 *

 * Frees the records which were returned by g_relation_select(). This

 * should always be called after g_relation_select() when you are

 * finished with the records. The records are not removed from the

 * #GRelation.

 *

 * Deprecated: 2.26: Rarely used API

 **/

void

g_tuples_destroy (GTuples *tuples0)

{

  GRealTuples *tuples = (GRealTuples*) tuples0;

  if (tuples)

    {

      g_free (tuples->data);

      g_free (tuples);

    }

}

/**

 * g_tuples_index:

 * @tuples: the tuple data, returned by g_relation_select().

 * @index_: the index of the record.

 * @field: the field to return.

 *

 * Gets a field from the records returned by g_relation_select(). It

 * returns the given field of the record at the given index. The

 * returned value should not be changed.

 *

 * Returns: the field of the record.

 *

 * Deprecated: 2.26: Rarely used API

 **/

gpointer

g_tuples_index (GTuples     *tuples0,

		gint         index,

		gint         field)

{

  GRealTuples *tuples = (GRealTuples*) tuples0;

  g_return_val_if_fail (tuples0 != NULL, NULL);

  g_return_val_if_fail (field < tuples->width, NULL);

  return tuples->data[index * tuples->width + field];

}

/* Print

 */

static void

g_relation_print_one (gpointer tuple_key,

		      gpointer tuple_value,

		      gpointer user_data)

{

  gint i;

  GString *gstring;

  GRelation* rel = (GRelation*) user_data;

  gpointer* tuples = (gpointer*) tuple_value;

  gstring = g_string_new ("[");

  for (i = 0; i < rel->fields; i += 1)

    {

      g_string_append_printf (gstring, "%p", tuples[i]);

      if (i < (rel->fields - 1))

	g_string_append (gstring, ",");

    }

  g_string_append (gstring, "]");

  g_log (G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "%s", gstring->str);

  g_string_free (gstring, TRUE);

}

static void

g_relation_print_index (gpointer tuple_key,

			gpointer tuple_value,

			gpointer user_data)

{

  GRelation* rel = (GRelation*) user_data;

  GHashTable* table = (GHashTable*) tuple_value;

  g_log (G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "*** key %p", tuple_key);

  g_hash_table_foreach (table,

			g_relation_print_one,

			rel);

}

/**

 * g_relation_print:

 * @relation: a #GRelation.

 *

 * Outputs information about all records in a #GRelation, as well as

 * the indexes. It is for debugging.

 *

 * Deprecated: 2.26: Rarely used API

 **/

void

g_relation_print (GRelation *relation)

{

  gint i;

  g_log (G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "*** all tuples (%d)", relation->count);

  g_hash_table_foreach (relation->all_tuples,

			g_relation_print_one,

			relation);

  for (i = 0; i < relation->fields; i += 1)

    {

      if (relation->hashed_tuple_tables[i] == NULL)

	continue;

      g_log (G_LOG_DOMAIN, G_LOG_LEVEL_INFO, "*** index %d", i);

      g_hash_table_foreach (relation->hashed_tuple_tables[i],

			    g_relation_print_index,

			    relation);

    }

}