initial commit

1 files changed, 214 insertions, 0 deletions

diff --git a/code/htable/hashtable_itr.c b/code/htable/hashtable_itr.c
new file mode 100755
index 0000000..3ee8fe2
--- /dev/null
+++ b/code/htable/hashtable_itr.c
@@ -0,0 +1,214 @@
+/* Copyright (C) 2002, 2004 Christopher Clark  <firstname.lastname@cl.cam.ac.uk> */
+
+#include "hashtable.h"
+#include "hashtable_private.h"
+#include "hashtable_itr.h"
+#include <stdlib.h> /* defines NULL */
+
+/*****************************************************************************/
+/* hashtable_iterator    - iterator constructor */
+
+int
+hashtable_iterator(struct hashtable_itr *itr, struct hashtable *h)
+{
+    unsigned int i, tablelength;
+    itr->h = h;
+    itr->e = NULL;
+    itr->parent = NULL;
+    tablelength = h->tablelength;
+    itr->index = tablelength;
+    if (0 == h->entrycount) return -1;
+
+    for (i = 0; i < tablelength; i++)
+    {
+        if (NULL != h->table[i])
+        {
+            itr->e = h->table[i];
+            itr->index = i;
+            break;
+        }
+    }
+    return -1;
+}
+
+/*****************************************************************************/
+/* key      - return the key of the (key,value) pair at the current position */
+/* value    - return the value of the (key,value) pair at the current position */
+
+void *
+hashtable_iterator_key(struct hashtable_itr *i)
+{ return i->e->k; }
+
+void *
+hashtable_iterator_value(struct hashtable_itr *i)
+{ return i->e->v; }
+
+/*****************************************************************************/
+/* advance - advance the iterator to the next element
+ *           returns zero if advanced to end of table */
+
+int
+hashtable_iterator_advance(struct hashtable_itr *itr)
+{
+    unsigned int j,tablelength;
+    struct entry **table;
+    struct entry *next;
+    if (NULL == itr->e) return 0; /* stupidity check */
+
+    next = itr->e->next;
+    if (NULL != next)
+    {
+        itr->parent = itr->e;
+        itr->e = next;
+        return -1;
+    }
+    tablelength = itr->h->tablelength;
+    itr->parent = NULL;
+    if (tablelength <= (j = ++(itr->index)))
+    {
+        itr->e = NULL;
+        return 0;
+    }
+    table = itr->h->table;
+    while (NULL == (next = table[j]))
+    {
+        if (++j >= tablelength)
+        {
+            itr->index = tablelength;
+            itr->e = NULL;
+            return 0;
+        }
+    }
+    itr->index = j;
+    itr->e = next;
+    return -1;
+}
+
+/*****************************************************************************/
+/* remove - remove the entry at the current iterator position
+ *          and advance the iterator, if there is a successive
+ *          element.
+ *          If you want the value, read it before you remove:
+ *          beware memory leaks if you don't.
+ *          Returns zero if end of iteration. --- modified by majstor */
+
+int
+hashtable_iterator_remove(struct hashtable_itr *itr)
+{
+    struct entry *remember_e, *remember_parent;
+    int ret;
+
+    /* Do the removal */
+    if (NULL == (itr->parent))
+    {
+        /* element is head of a chain */
+        itr->h->table[itr->index] = itr->e->next;
+    } else {
+        /* element is mid-chain */
+        itr->parent->next = itr->e->next;
+    }
+    /* itr->e is now outside the hashtable */
+    remember_e = itr->e;
+    itr->h->entrycount--;
+    if (itr->h->fn_free_k) itr->h->fn_free_k(remember_e->k);
+    if (itr->h->fn_free_v) itr->h->fn_free_v(remember_e->v);
+
+    /* Advance the iterator, correcting the parent */
+    remember_parent = itr->parent;
+    ret = hashtable_iterator_advance(itr);
+    if (itr->parent == remember_e) { itr->parent = remember_parent; }
+    itr->h->fn_free(remember_e);
+    return ret;
+}
+
+/*****************************************************************************/
+int /* returns zero if not found */
+hashtable_iterator_search(struct hashtable_itr *itr, void *k)
+{
+    struct entry *e, *parent;
+    unsigned int hashvalue, index;
+    struct hashtable *h = itr->h;
+    
+    hashvalue = hashtable_hash(h,k);
+    index = indexFor(h->tablelength,hashvalue);
+
+    e = h->table[index];
+    parent = NULL;
+    while (NULL != e)
+    {
+        /* Check hash value to short circuit heavier comparison */
+        if ((hashvalue == e->h) && (h->fn_eq(k, e->k)))
+        {
+            itr->index = index;
+            itr->e = e;
+            itr->parent = parent;
+            itr->h = h;
+            return -1;
+        }
+        parent = e;
+        e = e->next;
+    }
+    return 0;
+}
+
+
+/*****************************************************************************/
+int /* returns zero if not found */
+hashtable_iterator_search_next(struct hashtable_itr *itr, void *k)
+{
+    struct entry *e, *parent;
+    unsigned int hashvalue;
+    struct hashtable *h = itr->h;
+    if (NULL == itr->e) return 0; /* stupidity check */
+
+    hashvalue = hashtable_hash(h,k);
+    parent = itr->e;
+    e = itr->e->next;
+    while (NULL != e)
+    {
+        /* Check hash value to short circuit heavier comparison */
+        if ((hashvalue == e->h) && (h->fn_eq(k, e->k)))
+        {
+            itr->parent = parent;
+            itr->e = e;
+            return -1;
+        }
+        parent = e;
+        e = e->next;
+    }
+    return 0;
+}
+
+
+/*
+ * Copyright (c) 2002, 2004, Christopher Clark
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 
+ * * Neither the name of the original author; nor the names of any contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ * 
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/