upload http

JIRA: BOTTLENECK-10

Change-Id: I7598427ff904df438ce77c2819ee48ac75ffa8da
Signed-off-by: hongbotian <hongbo.tianhongbo@huawei.com>

1 files changed, 290 insertions, 0 deletions

diff --git a/rubbos/app/httpd-2.0.64/modules/experimental/cache_hash.c b/rubbos/app/httpd-2.0.64/modules/experimental/cache_hash.c
new file mode 100644
index 00000000..89552a18
--- /dev/null
+++ b/rubbos/app/httpd-2.0.64/modules/experimental/cache_hash.c
@@ -0,0 +1,290 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr_general.h"
+
+#include "mod_cache.h"
+#include "cache_hash.h"
+
+#if APR_HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#if APR_HAVE_STRING_H
+#include <string.h>
+#endif
+
+
+/*
+ * The internal form of a hash table.
+ *
+ * The table is an array indexed by the hash of the key; collisions
+ * are resolved by hanging a linked list of hash entries off each
+ * element of the array. Although this is a really simple design it
+ * isn't too bad given that pools have a low allocation overhead.
+ */
+
+typedef struct cache_hash_entry_t cache_hash_entry_t;
+
+struct cache_hash_entry_t {
+    cache_hash_entry_t	*next;
+    unsigned int	 hash;
+    const void		*key;
+    apr_ssize_t		 klen;
+    const void		*val;
+};
+
+/*
+ * Data structure for iterating through a hash table.
+ *
+ * We keep a pointer to the next hash entry here to allow the current
+ * hash entry to be freed or otherwise mangled between calls to
+ * cache_hash_next().
+ */
+struct cache_hash_index_t {
+    cache_hash_t	 *ht;
+    cache_hash_entry_t   *this, *next;
+    int                  index;
+};
+
+/*
+ * The size of the array is always a power of two. We use the maximum
+ * index rather than the size so that we can use bitwise-AND for
+ * modular arithmetic.
+ * The count of hash entries may be greater depending on the chosen
+ * collision rate.
+ */
+struct cache_hash_t {
+    cache_hash_entry_t   **array;
+    cache_hash_index_t     iterator;  /* For cache_hash_first(NULL, ...) */
+    int                  count, max;
+};
+
+/*
+ * Hash creation functions.
+ */
+static cache_hash_entry_t **alloc_array(cache_hash_t *ht, int max)
+{
+   return calloc(1, sizeof(*ht->array) * (max + 1));
+}
+
+CACHE_DECLARE(cache_hash_t *) cache_hash_make(apr_size_t size)
+{
+    cache_hash_t *ht;
+    ht = malloc(sizeof(cache_hash_t));
+    if (!ht) {
+        return NULL;
+    }
+    ht->count = 0;
+    ht->max = size;
+    ht->array = alloc_array(ht, ht->max);
+    if (!ht->array) {
+        free(ht);
+        return NULL;
+    }
+    return ht;
+}
+
+CACHE_DECLARE(void) cache_hash_free(cache_hash_t *ht)
+{
+    if (ht) {
+        if (ht->array) {
+            free (ht->array);
+        }
+        free (ht);
+    }
+}
+/*
+ * Hash iteration functions.
+ */
+
+CACHE_DECLARE(cache_hash_index_t *) cache_hash_next(cache_hash_index_t *hi)
+{
+    hi->this = hi->next;
+    while (!hi->this) {
+	if (hi->index > hi->ht->max)
+	    return NULL;
+	hi->this = hi->ht->array[hi->index++];
+    }
+    hi->next = hi->this->next;
+    return hi;
+}
+
+CACHE_DECLARE(cache_hash_index_t *) cache_hash_first(cache_hash_t *ht)
+{
+    cache_hash_index_t *hi;
+
+    hi = &ht->iterator;
+    hi->ht = ht;
+    hi->index = 0;
+    hi->this = NULL;
+    hi->next = NULL;
+    return cache_hash_next(hi);
+}
+
+CACHE_DECLARE(void) cache_hash_this(cache_hash_index_t *hi,
+                                  const void **key,
+                                  apr_ssize_t *klen,
+                                  void **val)
+{
+    if (key)  *key  = hi->this->key;
+    if (klen) *klen = hi->this->klen;
+    if (val)  *val  = (void *)hi->this->val;
+}
+
+
+/*
+ * This is where we keep the details of the hash function and control
+ * the maximum collision rate.
+ *
+ * If val is non-NULL it creates and initializes a new hash entry if
+ * there isn't already one there; it returns an updatable pointer so
+ * that hash entries can be removed.
+ */
+
+static cache_hash_entry_t **find_entry(cache_hash_t *ht,
+                                       const void *key,
+                                       apr_ssize_t klen,
+                                       const void *val)
+{
+    cache_hash_entry_t **hep, *he;
+    const unsigned char *p;
+    unsigned int hash;
+    apr_ssize_t i;
+
+    /*
+     * This is the popular `times 33' hash algorithm which is used by
+     * perl and also appears in Berkeley DB. This is one of the best
+     * known hash functions for strings because it is both computed
+     * very fast and distributes very well.
+     *
+     * The originator may be Dan Bernstein but the code in Berkeley DB
+     * cites Chris Torek as the source. The best citation I have found
+     * is "Chris Torek, Hash function for text in C, Usenet message
+     * <27038@mimsy.umd.edu> in comp.lang.c , October, 1990." in Rich
+     * Salz's USENIX 1992 paper about INN which can be found at
+     * <http://citeseer.nj.nec.com/salz92internetnews.html>.
+     *
+     * The magic of number 33, i.e. why it works better than many other
+     * constants, prime or not, has never been adequately explained by
+     * anyone. So I try an explanation: if one experimentally tests all
+     * multipliers between 1 and 256 (as I did while writing a low-level
+     * data structure library some time ago) one detects that even
+     * numbers are not useable at all. The remaining 128 odd numbers
+     * (except for the number 1) work more or less all equally well.
+     * They all distribute in an acceptable way and this way fill a hash
+     * table with an average percent of approx. 86%.
+     *
+     * If one compares the chi^2 values of the variants (see
+     * Bob Jenkins ``Hashing Frequently Asked Questions'' at
+     * http://burtleburtle.net/bob/hash/hashfaq.html for a description
+     * of chi^2), the number 33 not even has the best value. But the
+     * number 33 and a few other equally good numbers like 17, 31, 63,
+     * 127 and 129 have nevertheless a great advantage to the remaining
+     * numbers in the large set of possible multipliers: their multiply
+     * operation can be replaced by a faster operation based on just one
+     * shift plus either a single addition or subtraction operation. And
+     * because a hash function has to both distribute good _and_ has to
+     * be very fast to compute, those few numbers should be preferred.
+     *
+     *                  -- Ralf S. Engelschall <rse@engelschall.com>
+     */
+    hash = 0;
+    if (klen == CACHE_HASH_KEY_STRING) {
+        for (p = key; *p; p++) {
+            hash = hash * 33 + *p;
+        }
+        klen = p - (const unsigned char *)key;
+    }
+    else {
+        for (p = key, i = klen; i; i--, p++) {
+            hash = hash * 33 + *p;
+        }
+    }
+    
+    /* scan linked list */
+    for (hep = &ht->array[hash % ht->max], he = *hep;
+	 he;
+	 hep = &he->next, he = *hep) {
+	if (he->hash == hash &&
+	    he->klen == klen &&
+	    memcmp(he->key, key, klen) == 0)
+	    break;
+    }
+    if (he || !val)
+	return hep;
+    /* add a new entry for non-NULL values */
+    he = malloc(sizeof(*he));
+    if (!he) {
+        return NULL;
+    }
+    he->next = NULL;
+    he->hash = hash;
+    he->key  = key;
+    he->klen = klen;
+    he->val  = val;
+    *hep = he;
+    ht->count++;
+    return hep;
+}
+
+CACHE_DECLARE(void *) cache_hash_get(cache_hash_t *ht,
+                                   const void *key,
+                                   apr_ssize_t klen)
+{
+    cache_hash_entry_t *he;
+    he = *find_entry(ht, key, klen, NULL);
+    if (he)
+	return (void *)he->val;
+    else
+	return NULL;
+}
+
+CACHE_DECLARE(void *) cache_hash_set(cache_hash_t *ht,
+                                     const void *key,
+                                     apr_ssize_t klen,
+                                     const void *val)
+{
+    cache_hash_entry_t **hep, *tmp;
+    const void *tval;
+    hep = find_entry(ht, key, klen, val);
+    /* If hep == NULL, then the malloc() in find_entry failed */
+    if (hep && *hep) {
+        if (!val) {
+            /* delete entry */
+            tval = (*hep)->val;
+            tmp = *hep;
+            *hep = (*hep)->next;
+            free(tmp);
+            --ht->count;
+        }
+        else {
+            /* replace entry */
+            tval = (*hep)->val;
+            (*hep)->val = val;
+        }
+        /* Return the object just removed from the cache to let the 
+         * caller clean it up. Cast the constness away upon return.
+         */
+        return (void *) tval;
+    }
+    /* else key not present and val==NULL */
+    return NULL;
+}
+
+CACHE_DECLARE(int) cache_hash_count(cache_hash_t *ht)
+{
+    return ht->count;
+}