fs layout updated

1 files changed, 263 insertions, 0 deletions

diff --git a/code/core/htable/hashtable.c b/code/core/htable/hashtable.c
new file mode 100755
index 0000000..8174a5d
--- /dev/null
+++ b/code/core/htable/hashtable.c
@@ -0,0 +1,263 @@
+/* Copyright (C) 2004 Christopher Clark <firstname.lastname@cl.cam.ac.uk> */
+
+#include "hashtable.h"
+#include "hashtable_private.h"
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+
+/*
+Credit for primes table: Aaron Krowne
+ http://br.endernet.org/~akrowne/
+ http://planetmath.org/encyclopedia/GoodHashTablePrimes.html
+*/
+static const unsigned int primes[] = {
+53, 97, 193, 389,
+769, 1543, 3079, 6151,
+12289, 24593, 49157, 98317,
+196613, 393241, 786433, 1572869,
+3145739, 6291469, 12582917, 25165843,
+50331653, 100663319, 201326611, 402653189,
+805306457, 1610612741
+};
+const unsigned int prime_table_length = sizeof(primes)/sizeof(primes[0]);
+const float max_load_factor = 0.65;
+
+/*****************************************************************************/
+int
+create_hashtable(struct hashtable *h, unsigned int minsize,
+                 unsigned int (*hash_fn) (void*),
+                 int (*eq_fn) (void*,void*),
+                 void *(*malloc_fn) (size_t),
+                 void *(*realloc_fn) (void*,size_t),
+                 void (*free_fn) (void*))
+{
+    unsigned int pindex, size = primes[0];
+    /* Check requested hashtable isn't too large */
+    if (minsize > (1u << 30)) return 0;
+    /* Enforce size as prime */
+    for (pindex=0; pindex < prime_table_length; pindex++) {
+        if (primes[pindex] > minsize) { size = primes[pindex]; break; }
+    }
+    h->fn_malloc    = malloc_fn ? malloc_fn : malloc;
+    h->fn_realloc   = realloc_fn ? realloc_fn : realloc;
+    h->fn_free      = free_fn ? free_fn : free;
+    h->tablelength  = size;
+    h->primeindex   = pindex;
+    h->entrycount   = 0;
+    h->fn_hash      = hash_fn;
+    h->fn_eq        = eq_fn;
+    h->loadlimit    = (unsigned int) ceil(size * max_load_factor);
+    h->table = h->fn_malloc(sizeof(struct entry *) * size);
+    if (NULL == h->table) return 0; /*oom*/
+    memset(h->table, 0, size * sizeof(struct entry *));
+    return -1;
+}
+
+/*****************************************************************************/
+unsigned int
+hashtable_hash(struct hashtable *h, void *k)
+{
+    /* Aim to protect against poor hash functions by adding logic here
+     * - logic taken from java 1.4 hashtable source */
+    unsigned int i = h->fn_hash(k);
+    i += ~(i << 9);
+    i ^=  ((i >> 14) | (i << 18)); /* >>> */
+    i +=  (i << 4);
+    i ^=  ((i >> 10) | (i << 22)); /* >>> */
+    return i;
+}
+
+/*****************************************************************************/
+static int
+hashtable_expand(struct hashtable *h)
+{
+    /* Double the size of the table to accomodate more entries */
+    struct entry **newtable;
+    struct entry *e;
+    struct entry **pE;
+    unsigned int newsize, i, index;
+    /* Check we're not hitting max capacity */
+    if (h->primeindex == (prime_table_length - 1)) return 0;
+    newsize = primes[++(h->primeindex)];
+
+    newtable = h->fn_malloc(sizeof(struct entry *) * newsize);
+    if (NULL != newtable)
+    {
+        memset(newtable, 0, newsize * sizeof(struct entry *));
+        /* This algorithm is not 'stable'. ie. it reverses the list
+         * when it transfers entries between the tables */
+        for (i = 0; i < h->tablelength; i++) {
+            while (NULL != (e = h->table[i])) {
+                h->table[i] = e->next;
+                index = indexFor(newsize,e->h);
+                e->next = newtable[index];
+                newtable[index] = e;
+            }
+        }
+        h->fn_free(h->table);
+        h->table = newtable;
+    }
+    /* Plan B: realloc instead */
+    else 
+    {
+        newtable = h->fn_realloc(h->table, newsize * sizeof(struct entry *));
+        if (NULL == newtable) { (h->primeindex)--; return 0; }
+        h->table = newtable;
+        memset(newtable[h->tablelength], 0, newsize - h->tablelength);
+        for (i = 0; i < h->tablelength; i++) {
+            for (pE = &(newtable[i]), e = *pE; e != NULL; e = *pE) {
+                index = indexFor(newsize,e->h);
+                if (index == i)
+                {
+                    pE = &(e->next);
+                }
+                else
+                {
+                    *pE = e->next;
+                    e->next = newtable[index];
+                    newtable[index] = e;
+                }
+            }
+        }
+    }
+    h->tablelength = newsize;
+    h->loadlimit   = (unsigned int) ceil(newsize * max_load_factor);
+    return -1;
+}
+
+/*****************************************************************************/
+unsigned int
+hashtable_count(struct hashtable *h)
+{
+    return h->entrycount;
+}
+
+/*****************************************************************************/
+int
+hashtable_insert(struct hashtable *h, void *k, void *v)
+{
+    /* This method allows duplicate keys - but they shouldn't be used */
+    unsigned int index;
+    struct entry *e;
+    if (++(h->entrycount) > h->loadlimit)
+    {
+        /* Ignore the return value. If expand fails, we should
+         * still try cramming just this value into the existing table
+         * -- we may not have memory for a larger table, but one more
+         * element may be ok. Next time we insert, we'll try expanding again.*/
+        hashtable_expand(h);
+    }
+    e = h->fn_malloc(sizeof(struct entry));
+    if (NULL == e) { --(h->entrycount); return 0; } /*oom*/
+    e->h = hashtable_hash(h,k);
+    index = indexFor(h->tablelength,e->h);
+    e->k = k;
+    e->v = v;
+    e->next = h->table[index];
+    h->table[index] = e;
+    return -1;
+}
+
+/*****************************************************************************/
+void * /* returns value associated with key */
+hashtable_search(struct hashtable *h, void *k)
+{
+    struct entry *e;
+    unsigned int hashvalue, index;
+    hashvalue = hashtable_hash(h,k);
+    index = indexFor(h->tablelength,hashvalue);
+    e = h->table[index];
+    while (NULL != e)
+    {
+        /* Check hash value to short circuit heavier comparison */
+        if ((hashvalue == e->h) && (h->fn_eq(k, e->k))) return e->v;
+        e = e->next;
+    }
+    return NULL;
+}
+
+/*****************************************************************************/
+void * /* returns value associated with key --- modified by majstor */
+hashtable_remove(struct hashtable *h, void *k)
+{
+    /* TODO: consider compacting the table when the load factor drops enough,
+     *       or provide a 'compact' method. */
+
+    struct entry *e;
+    struct entry **pE;
+    void *v;
+    unsigned int hashvalue, index;
+
+    hashvalue = hashtable_hash(h,k);
+    index = indexFor(h->tablelength,hashtable_hash(h,k));
+    pE = &(h->table[index]);
+    e = *pE;
+    while (NULL != e)
+    {
+        /* Check hash value to short circuit heavier comparison */
+        if ((hashvalue == e->h) && (h->fn_eq(k, e->k)))
+        {
+            *pE = e->next;
+            h->entrycount--;
+            v = e->v;
+            if (h->fn_free_k) h->fn_free_k(e->k);
+            h->fn_free(e);
+            return v;
+        }
+        pE = &(e->next);
+        e = e->next;
+    }
+    return NULL;
+}
+
+/*****************************************************************************/
+/* destroy --- modified by majstor */
+void
+hashtable_destroy(struct hashtable *h)
+{
+    unsigned int i;
+    struct entry *e, *f;
+    struct entry **table = h->table;
+
+    for (i = 0; i < h->tablelength; i++)
+    {
+        e = table[i];
+        while (NULL != e)
+        { f = e; e = e->next; if (h->fn_free_k) h->fn_free_k(f->k); if (h->fn_free_v) h->fn_free_v(f->v); h->fn_free(f); }
+    }
+    h->fn_free(h->table);
+}
+
+/*
+ * Copyright (c) 2002, 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.
+*/