--- /dev/null
+/*
+ * hash.c: chained hash tables
+ *
+ * Reference: Your favorite introductory book on algorithms
+ *
+ * Copyright (C) 2000 Bjorn Reese and Daniel Veillard.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS AND
+ * CONTRIBUTORS ACCEPT NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER.
+ *
+ * Author: breese@users.sourceforge.net
+ */
+
+#define IN_LIBXML
+
+#include <string.h>
+#include "hash.h"
+
+#define MAX_HASH_LEN 8
+
+/* #define DEBUG_GROW */
+
+/*
+ * A single entry in the hash table
+ */
+typedef struct _xenHashEntry xenHashEntry;
+typedef xenHashEntry *xenHashEntryPtr;
+struct _xenHashEntry {
+ struct _xenHashEntry *next;
+ char *name;
+ void *payload;
+ int valid;
+};
+
+/*
+ * The entire hash table
+ */
+struct _xenHashTable {
+ struct _xenHashEntry *table;
+ int size;
+ int nbElems;
+};
+
+/*
+ * xenHashComputeKey:
+ * Calculate the hash key
+ */
+static unsigned long
+xenHashComputeKey(xenHashTablePtr table, const char *name) {
+ unsigned long value = 0L;
+ char ch;
+
+ if (name != NULL) {
+ value += 30 * (*name);
+ while ((ch = *name++) != 0) {
+ value = value ^ ((value << 5) + (value >> 3) + (unsigned long)ch);
+ }
+ }
+ return (value % table->size);
+}
+
+/**
+ * xenHashCreate:
+ * @size: the size of the hash table
+ *
+ * Create a new xenHashTablePtr.
+ *
+ * Returns the newly created object, or NULL if an error occured.
+ */
+xenHashTablePtr
+xenHashCreate(int size) {
+ xenHashTablePtr table;
+
+ if (size <= 0)
+ size = 256;
+
+ table = malloc(sizeof(xenHashTable));
+ if (table) {
+ table->size = size;
+ table->nbElems = 0;
+ table->table = malloc(size * sizeof(xenHashEntry));
+ if (table->table) {
+ memset(table->table, 0, size * sizeof(xenHashEntry));
+ return(table);
+ }
+ free(table);
+ }
+ return(NULL);
+}
+
+/**
+ * xenHashGrow:
+ * @table: the hash table
+ * @size: the new size of the hash table
+ *
+ * resize the hash table
+ *
+ * Returns 0 in case of success, -1 in case of failure
+ */
+static int
+xenHashGrow(xenHashTablePtr table, int size) {
+ unsigned long key;
+ int oldsize, i;
+ xenHashEntryPtr iter, next;
+ struct _xenHashEntry *oldtable;
+#ifdef DEBUG_GROW
+ unsigned long nbElem = 0;
+#endif
+
+ if (table == NULL)
+ return(-1);
+ if (size < 8)
+ return(-1);
+ if (size > 8 * 2048)
+ return(-1);
+
+ oldsize = table->size;
+ oldtable = table->table;
+ if (oldtable == NULL)
+ return(-1);
+
+ table->table = malloc(size * sizeof(xenHashEntry));
+ if (table->table == NULL) {
+ table->table = oldtable;
+ return(-1);
+ }
+ memset(table->table, 0, size * sizeof(xenHashEntry));
+ table->size = size;
+
+ /* If the two loops are merged, there would be situations where
+ a new entry needs to allocated and data copied into it from
+ the main table. So instead, we run through the array twice, first
+ copying all the elements in the main array (where we can't get
+ conflicts) and then the rest, so we only free (and don't allocate)
+ */
+ for (i = 0; i < oldsize; i++) {
+ if (oldtable[i].valid == 0)
+ continue;
+ key = xenHashComputeKey(table, oldtable[i].name);
+ memcpy(&(table->table[key]), &(oldtable[i]), sizeof(xenHashEntry));
+ table->table[key].next = NULL;
+ }
+
+ for (i = 0; i < oldsize; i++) {
+ iter = oldtable[i].next;
+ while (iter) {
+ next = iter->next;
+
+ /*
+ * put back the entry in the new table
+ */
+
+ key = xenHashComputeKey(table, iter->name);
+ if (table->table[key].valid == 0) {
+ memcpy(&(table->table[key]), iter, sizeof(xenHashEntry));
+ table->table[key].next = NULL;
+ free(iter);
+ } else {
+ iter->next = table->table[key].next;
+ table->table[key].next = iter;
+ }
+
+#ifdef DEBUG_GROW
+ nbElem++;
+#endif
+
+ iter = next;
+ }
+ }
+
+ free(oldtable);
+
+#ifdef DEBUG_GROW
+ xmlGenericError(xmlGenericErrorContext,
+ "xenHashGrow : from %d to %d, %d elems\n", oldsize, size, nbElem);
+#endif
+
+ return(0);
+}
+
+/**
+ * xenHashFree:
+ * @table: the hash table
+ * @f: the deallocator function for items in the hash
+ *
+ * Free the hash @table and its contents. The userdata is
+ * deallocated with @f if provided.
+ */
+void
+xenHashFree(xenHashTablePtr table, xenHashDeallocator f) {
+ int i;
+ xenHashEntryPtr iter;
+ xenHashEntryPtr next;
+ int inside_table = 0;
+ int nbElems;
+
+ if (table == NULL)
+ return;
+ if (table->table) {
+ nbElems = table->nbElems;
+ for(i = 0; (i < table->size) && (nbElems > 0); i++) {
+ iter = &(table->table[i]);
+ if (iter->valid == 0)
+ continue;
+ inside_table = 1;
+ while (iter) {
+ next = iter->next;
+ if ((f != NULL) && (iter->payload != NULL))
+ f(iter->payload, iter->name);
+ if (iter->name)
+ free(iter->name);
+ iter->payload = NULL;
+ if (!inside_table)
+ free(iter);
+ nbElems--;
+ inside_table = 0;
+ iter = next;
+ }
+ inside_table = 0;
+ }
+ free(table->table);
+ }
+ free(table);
+}
+
+/**
+ * xenHashAddEntry3:
+ * @table: the hash table
+ * @name: the name of the userdata
+ * @userdata: a pointer to the userdata
+ *
+ * Add the @userdata to the hash @table. This can later be retrieved
+ * by using @name. Duplicate entries generate errors.
+ *
+ * Returns 0 the addition succeeded and -1 in case of error.
+ */
+int
+xenHashAddEntry(xenHashTablePtr table, const char *name,
+ void *userdata) {
+ unsigned long key, len = 0;
+ xenHashEntryPtr entry;
+ xenHashEntryPtr insert;
+
+ if ((table == NULL) || (name == NULL))
+ return(-1);
+
+ /*
+ * Check for duplicate and insertion location.
+ */
+ key = xenHashComputeKey(table, name);
+ if (table->table[key].valid == 0) {
+ insert = NULL;
+ } else {
+ for (insert = &(table->table[key]); insert->next != NULL;
+ insert = insert->next) {
+ if (!strcmp(insert->name, name))
+ return(-1);
+ len++;
+ }
+ if (!strcmp(insert->name, name))
+ return(-1);
+ }
+
+ if (insert == NULL) {
+ entry = &(table->table[key]);
+ } else {
+ entry = malloc(sizeof(xenHashEntry));
+ if (entry == NULL)
+ return(-1);
+ }
+
+ entry->name = strdup(name);
+ entry->payload = userdata;
+ entry->next = NULL;
+ entry->valid = 1;
+
+
+ if (insert != NULL)
+ insert->next = entry;
+
+ table->nbElems++;
+
+ if (len > MAX_HASH_LEN)
+ xenHashGrow(table, MAX_HASH_LEN * table->size);
+
+ return(0);
+}
+
+/**
+ * xenHashUpdateEntry:
+ * @table: the hash table
+ * @name: the name of the userdata
+ * @userdata: a pointer to the userdata
+ * @f: the deallocator function for replaced item (if any)
+ *
+ * Add the @userdata to the hash @table. This can later be retrieved
+ * by using @name. Existing entry for this tuple
+ * will be removed and freed with @f if found.
+ *
+ * Returns 0 the addition succeeded and -1 in case of error.
+ */
+int
+xenHashUpdateEntry(xenHashTablePtr table, const char *name,
+ void *userdata, xenHashDeallocator f) {
+ unsigned long key;
+ xenHashEntryPtr entry;
+ xenHashEntryPtr insert;
+
+ if ((table == NULL) || name == NULL)
+ return(-1);
+
+ /*
+ * Check for duplicate and insertion location.
+ */
+ key = xenHashComputeKey(table, name);
+ if (table->table[key].valid == 0) {
+ insert = NULL;
+ } else {
+ for (insert = &(table->table[key]); insert->next != NULL;
+ insert = insert->next) {
+ if (!strcmp(insert->name, name)) {
+ if (f)
+ f(insert->payload, insert->name);
+ insert->payload = userdata;
+ return(0);
+ }
+ }
+ if (!strcmp(insert->name, name)) {
+ if (f)
+ f(insert->payload, insert->name);
+ insert->payload = userdata;
+ return(0);
+ }
+ }
+
+ if (insert == NULL) {
+ entry = &(table->table[key]);
+ } else {
+ entry = malloc(sizeof(xenHashEntry));
+ if (entry == NULL)
+ return(-1);
+ }
+
+ entry->name = strdup(name);
+ entry->payload = userdata;
+ entry->next = NULL;
+ entry->valid = 1;
+ table->nbElems++;
+
+
+ if (insert != NULL) {
+ insert->next = entry;
+ }
+ return(0);
+}
+
+/**
+ * xenHashLookup:
+ * @table: the hash table
+ * @name: the name of the userdata
+ *
+ * Find the userdata specified by the (@name, @name2, @name3) tuple.
+ *
+ * Returns the a pointer to the userdata
+ */
+void *
+xenHashLookup(xenHashTablePtr table, const char *name) {
+ unsigned long key;
+ xenHashEntryPtr entry;
+
+ if (table == NULL)
+ return(NULL);
+ if (name == NULL)
+ return(NULL);
+ key = xenHashComputeKey(table, name);
+ if (table->table[key].valid == 0)
+ return(NULL);
+ for (entry = &(table->table[key]); entry != NULL; entry = entry->next) {
+ if (!strcmp(entry->name, name))
+ return(entry->payload);
+ }
+ return(NULL);
+}
+
+/**
+ * xenHashSize:
+ * @table: the hash table
+ *
+ * Query the number of elements installed in the hash @table.
+ *
+ * Returns the number of elements in the hash table or
+ * -1 in case of error
+ */
+int
+xenHashSize(xenHashTablePtr table) {
+ if (table == NULL)
+ return(-1);
+ return(table->nbElems);
+}
+
+/**
+ * xenHashRemoveEntry:
+ * @table: the hash table
+ * @name: the name of the userdata
+ * @f: the deallocator function for removed item (if any)
+ *
+ * Find the userdata specified by the @name and remove
+ * it from the hash @table. Existing userdata for this tuple will be removed
+ * and freed with @f.
+ *
+ * Returns 0 if the removal succeeded and -1 in case of error or not found.
+ */
+int
+xenHashRemoveEntry(xenHashTablePtr table, const char *name,
+ xenHashDeallocator f) {
+ unsigned long key;
+ xenHashEntryPtr entry;
+ xenHashEntryPtr prev = NULL;
+
+ if (table == NULL || name == NULL)
+ return(-1);
+
+ key = xenHashComputeKey(table, name);
+ if (table->table[key].valid == 0) {
+ return(-1);
+ } else {
+ for (entry = &(table->table[key]); entry != NULL; entry = entry->next) {
+ if (!strcmp(entry->name, name)) {
+ if ((f != NULL) && (entry->payload != NULL))
+ f(entry->payload, entry->name);
+ entry->payload = NULL;
+ if(entry->name)
+ free(entry->name);
+ if(prev) {
+ prev->next = entry->next;
+ free(entry);
+ } else {
+ if (entry->next == NULL) {
+ entry->valid = 0;
+ } else {
+ entry = entry->next;
+ memcpy(&(table->table[key]), entry, sizeof(xenHashEntry));
+ free(entry);
+ }
+ }
+ table->nbElems--;
+ return(0);
+ }
+ prev = entry;
+ }
+ return(-1);
+ }
+}
+
projects / thirdparty / libvirt.git / commitdiff
