glib/grel.c

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/* 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 Library General Public
* License as published by the Free Software Foundation; either
* version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "glib.h"
#include <stdarg.h>
#include <string.h>
typedef struct _GRealRelation GRealRelation;
typedef struct _GRealTuples GRealTuples;
struct _GRealRelation
{
gint fields;
gint current_field;
GHashTable *all_tuples;
GHashTable **hashed_tuple_tables;
GMemChunk *tuple_chunk;
gint count;
};
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)
{
gpointer* a = (gpointer*) v_a;
return (gulong)a[0] ^ (gulong)a[1];
}
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 GCompareFunc
tuple_equal (gint fields)
{
switch (fields)
{
case 2:
return tuple_equal_2;
default:
g_error ("no tuple equal for %d", fields);
}
return NULL;
}
GRelation*
g_relation_new (gint fields)
{
GRealRelation* rel = g_new0 (GRealRelation, 1);
rel->fields = fields;
rel->tuple_chunk = g_mem_chunk_new ("Relation Chunk",
fields * sizeof (gpointer),
fields * sizeof (gpointer) * 128,
G_ALLOC_AND_FREE);
rel->all_tuples = g_hash_table_new (tuple_hash (fields), tuple_equal (fields));
rel->hashed_tuple_tables = g_new0 (GHashTable*, fields);
return (GRelation*) rel;
}
static void
g_relation_free_array (gpointer key, gpointer value, gpointer user_data)
{
g_hash_table_destroy ((GHashTable*) value);
}
void
g_relation_destroy (GRelation *relation)
{
GRealRelation *rel = (GRealRelation *) relation;
gint i;
if (rel)
{
g_hash_table_destroy (rel->all_tuples);
g_mem_chunk_destroy (rel->tuple_chunk);
for (i = 0; i < rel->fields; i += 1)
{
if (rel->hashed_tuple_tables[i])
{
g_hash_table_foreach (rel->hashed_tuple_tables[i], g_relation_free_array, NULL);
g_hash_table_destroy (rel->hashed_tuple_tables[i]);
}
}
g_free (rel->hashed_tuple_tables);
g_free (rel);
}
}
void
g_relation_index (GRelation *relation,
gint field,
GHashFunc hash_func,
GCompareFunc key_compare_func)
{
GRealRelation *rel = (GRealRelation *) relation;
g_assert (rel->count == 0 && rel->hashed_tuple_tables[field] == NULL);
rel->hashed_tuple_tables[field] = g_hash_table_new (hash_func, key_compare_func);
}
void
g_relation_insert (GRelation *relation,
...)
{
GRealRelation *rel = (GRealRelation *) relation;
gpointer* tuple = g_chunk_new (gpointer, rel->tuple_chunk);
va_list args;
gint i;
va_start(args, relation);
for (i = 0; i < rel->fields; i += 1)
tuple[i] = va_arg(args, gpointer);
va_end(args);
g_hash_table_insert (rel->all_tuples, tuple, tuple);
rel->count += 1;
for (i = 0; i < rel->fields; i += 1)
{
GHashTable *table;
gpointer key;
GHashTable *per_key_table;
table = rel->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 (rel->fields), tuple_equal (rel->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;
GRealRelation *rel = (GRealRelation *) user_data;
gint j;
g_assert (tuple_key == tuple_value);
for (j = 0; j < rel->fields; j += 1)
{
GHashTable *one_table = rel->hashed_tuple_tables[j];
gpointer one_key;
GHashTable *per_key_table;
if (one_table == NULL)
continue;
if (j == rel->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);
}
g_hash_table_remove (rel->all_tuples, tuple);
rel->count -= 1;
}
gint
g_relation_delete (GRelation *relation,
gconstpointer key,
gint field)
{
GRealRelation *rel = (GRealRelation *) relation;
GHashTable *table = rel->hashed_tuple_tables[field];
GHashTable *key_table;
gint count = rel->count;
g_assert (table);
key_table = g_hash_table_lookup (table, key);
if (!key_table)
return 0;
rel->current_field = field;
g_hash_table_foreach (key_table, g_relation_delete_tuple, rel);
g_hash_table_remove (table, key);
g_hash_table_destroy (key_table);
/* @@@ FIXME: Remove empty hash tables. */
return count - rel->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;
}
GTuples*
g_relation_select (GRelation *relation,
gconstpointer key,
gint field)
{
GRealRelation *rel = (GRealRelation *) relation;
GHashTable *table = rel->hashed_tuple_tables[field];
GHashTable *key_table;
GRealTuples *tuples = g_new0 (GRealTuples, 1);
gint count;
g_assert (table);
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) * rel->fields * count);
tuples->width = rel->fields;
g_hash_table_foreach (key_table, g_relation_select_tuple, tuples);
g_assert (count == tuples->len);
return (GTuples*)tuples;
}
gint
g_relation_count (GRelation *relation,
gconstpointer key,
gint field)
{
GRealRelation *rel = (GRealRelation *) relation;
GHashTable *table = rel->hashed_tuple_tables[field];
GHashTable *key_table;
g_assert (table);
key_table = g_hash_table_lookup (table, key);
if (!key_table)
return 0;
return g_hash_table_size (key_table);
}
gboolean
g_relation_exists (GRelation *relation, ...)
{
GRealRelation *rel = (GRealRelation *) relation;
gpointer* tuple = g_chunk_new (gpointer, rel->tuple_chunk);
va_list args;
gint i;
gboolean result;
va_start(args, relation);
for (i = 0; i < rel->fields; i += 1)
tuple[i] = va_arg(args, gpointer);
va_end(args);
result = g_hash_table_lookup (rel->all_tuples, tuple) != NULL;
g_mem_chunk_free (rel->tuple_chunk, tuple);
return result;
}
void
g_tuples_destroy (GTuples *tuples0)
{
GRealTuples *tuples = (GRealTuples*) tuples0;
if (tuples)
{
g_free (tuples->data);
g_free (tuples);
}
}
gpointer
g_tuples_index (GTuples *tuples0,
gint index,
gint field)
{
GRealTuples *tuples = (GRealTuples*) tuples0;
g_assert (field < tuples->width);
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;
GRealRelation* rel = (GRealRelation*) user_data;
gpointer* tuples = (gpointer*) tuple_value;
gstring = g_string_new ("[");
for (i = 0; i < rel->fields; i += 1)
{
g_string_sprintfa (gstring, "%p", tuples[i]);
if (i < (rel->fields - 1))
g_string_append (gstring, ",");
}
g_string_append (gstring, "]");
g_log (g_log_domain_glib, G_LOG_LEVEL_INFO, gstring->str);
g_string_free (gstring, TRUE);
}
static void
g_relation_print_index (gpointer tuple_key,
gpointer tuple_value,
gpointer user_data)
{
GRealRelation* rel = (GRealRelation*) user_data;
GHashTable* table = (GHashTable*) tuple_value;
g_log (g_log_domain_glib, G_LOG_LEVEL_INFO, "*** key %p", tuple_key);
g_hash_table_foreach (table,
g_relation_print_one,
rel);
}
void
g_relation_print (GRelation *relation)
{
gint i;
GRealRelation* rel = (GRealRelation*) relation;
g_log (g_log_domain_glib, G_LOG_LEVEL_INFO, "*** all tuples (%d)", rel->count);
g_hash_table_foreach (rel->all_tuples,
g_relation_print_one,
rel);
for (i = 0; i < rel->fields; i += 1)
{
if (rel->hashed_tuple_tables[i] == NULL)
continue;
g_log (g_log_domain_glib, G_LOG_LEVEL_INFO, "*** index %d", i);
g_hash_table_foreach (rel->hashed_tuple_tables[i],
g_relation_print_index,
rel);
}
}