[PATCH] apr_hash_this_{key,klen,val}

[Hyrum K. Wright]

In using the apr_hash datastructure in Subversion, we've found that we
often only want the key or value from a hash.  Furthermore, casting
the various return parameters has proven cumbersome.  To solve this
problem, we've introduced three helper functions to return the key,
key length, and value from a hash iterator.

We've found these functions quite useful, so I'm including a patch to
add them to APR proper.  The patch is against trunk, but if possible,
I'd like to see these APIs backported to 1.4.x and 1.5.x.

Thanks,
-Hyrum

Index: tables/apr_hash.c
===================================================================
--- tables/apr_hash.c   (revision 920903)
+++ tables/apr_hash.c   (working copy)
@@ -156,7 +156,31 @@ APR_DECLARE(void) apr_hash_this(apr_hash_index_t *
     if (val)  *val  = (void *)hi->this->val;
 }
 
+APR_DECLARE(const void *) apr_hash_this_key(apr_hash_index_t *hi)
+{
+    const void *key;
 
+    apr_hash_this(hi, &key, NULL, NULL);
+    return key;
+}
+
+APR_DECLARE(apr_ssize_t) apr_hash_this_klen(apr_hash_index_t *hi)
+{
+    apr_ssize_t klen;
+
+    apr_hash_this(hi, NULL, &klen, NULL);
+    return klen;
+}
+
+APR_DECLARE(void *) apr_hash_this_val(apr_hash_index_t *hi)
+{
+    void *val;
+
+    apr_hash_this(hi, NULL, NULL, &val);
+    return val;
+}
+
+
 /*
  * Expanding a hash table
  */
Index: test/testhash.c
===================================================================
--- test/testhash.c     (revision 920903)
+++ test/testhash.c     (working copy)
@@ -32,12 +32,13 @@ static int comp_string(const void *str1, const voi
 static void dump_hash(apr_pool_t *p, apr_hash_t *h, char str[][MAX_LTH]) 
 {
     apr_hash_index_t *hi;
-    char *val, *key;
-    apr_ssize_t len;
     int i = 0;
 
     for (hi = apr_hash_first(p, h); hi; hi = apr_hash_next(hi)) {
-        apr_hash_this(hi,(void*) &key, &len, (void*) &val);
+        char *key = apr_hash_this_key(hi);
+        apr_ssize_t len = apr_hash_this_klen(hi);
+        char *val = apr_hash_this_val(hi);
+
         str[i][0]='\0';
         apr_snprintf(str[i], MAX_LTH, "%sKey %s (%" APR_SSIZE_T_FMT ") Value 
%s\n",
                  str[i], key, len, val);
Index: include/apr_hash.h
===================================================================
--- include/apr_hash.h  (revision 920903)
+++ include/apr_hash.h  (working copy)
@@ -167,6 +167,27 @@ APR_DECLARE(void) apr_hash_this(apr_hash_index_t *
                                 apr_ssize_t *klen, void **val);
 
 /**
+ * Get the current entry's key from the iteration state.
+ * @param hi The iteration state
+ * @return The pointer to the key
+ */
+APR_DECLARE(const void*) apr_hash_this_key(apr_hash_index_t *hi);
+
+/**
+ * Get the current entry's key length from the iteration state.
+ * @param hi The iteration state
+ * @return The key length
+ */
+APR_DECLARE(apr_ssize_t) apr_hash_this_klen(apr_hash_index_t *hi);
+
+/**
+ * Get the current entry's value from the iteration state.
+ * @param hi The iteration state
+ * @return The pointer to the value
+ */
+APR_DECLARE(void*) apr_hash_this_val(apr_hash_index_t *hi);
+
+/**
  * Get the number of key/value pairs in the hash table.
  * @param ht The hash table
  * @return The number of key/value pairs in the hash table.