change the ends_option_list growing logic to be in line with rr_list

diff --git a/edns.c b/edns.c
index 5b11f562ecc05b6ce95ca516668b66741b4d2a4f..10f39d999f4d2a4819dde35380649366d7fe912f 100644 (file)
--- a/edns.c
+++ b/edns.c
@@ -12,8 +12,10 @@
 
 #include <ldns/ldns.h>
 
+#define LDNS_OPTIONLIST_INIT 8
+
 /*
- * Access functions 
+ * Access functions
  * functions to get and set type checking
  */
 
@@ -173,6 +175,7 @@ ldns_edns_option_list_new()
        }
 
        option_list->_option_count = 0;
+       option_list->_option_capacity = 0;
        option_list->_options_size = 0;
        option_list->_options = NULL;
        return option_list;
@@ -297,34 +300,58 @@ bool
 ldns_edns_option_list_push(ldns_edns_option_list *option_list,
        ldns_edns_option *option)
 {
+       size_t cap;
+       size_t option_count;
+
        assert(option_list != NULL);
 
-       if (option != NULL) {
+       if (option == NULL) {
+               return false;
+       }
+
+       cap = option_list->_option_capacity;
+       option_count = ldns_edns_option_list_get_count(option_list);
+
+       /* verify we need to grow the array to fit the new option */
+       if (option_count+1 > cap) {
+               ldns_edns_option **new_list;
+
+               /* initialize the capacity if needed, otherwise grow by doubling */
+               if (cap == 0) {
+                       cap = LDNS_OPTIONLIST_INIT; /* initial list size */
+               } else {
+                       cap *= 2;
+               }
+
+               new_list = LDNS_XREALLOC(option_list->_options,
+                       ldns_edns_option *, cap);
 
-               /* grow the array */
-               option_list->_options = LDNS_XREALLOC(option_list->_options,
-                       ldns_edns_option *, option_list->_option_count + 1);
-               if (!option_list) {
+               if (!new_list) {
                        return false;
                }
-               ldns_edns_option_list_set_option(option_list, option,
-                       option_list->_option_count);
-               option_list->_option_count += 1;
 
-               return true;
+               option_list->_options = new_list;
+               option_list->_option_capacity = cap;
        }
-       return false;
+
+       /* add the new option */
+       ldns_edns_option_list_set_option(option_list, option,
+               option_list->_option_count);
+       option_list->_option_count += 1;
+
+       return true;
 }
 
 ldns_edns_option *
 ldns_edns_option_list_pop(ldns_edns_option_list *option_list)
 {
-       ldns_edns_option ** new_list;
        ldns_edns_option* pop;
        size_t count;
+       size_t cap;
 
        assert(option_list != NULL);
 
+       cap = option_list->_option_capacity;
        count = ldns_edns_option_list_get_count(option_list);
 
        if (count == 0){
@@ -334,12 +361,20 @@ ldns_edns_option_list_pop(ldns_edns_option_list *option_list)
        pop = ldns_edns_option_list_get_option(option_list, count-1);
 
        /* shrink the array */
-       new_list = LDNS_XREALLOC(option_list->_options, ldns_edns_option *, count -1);
-       if (new_list){
-               option_list->_options = new_list;
+       if (cap > LDNS_OPTIONLIST_INIT && count-1 <= cap/2) {
+               ldns_edns_option **new_list;
+
+               cap /= 2;
+
+               new_list = LDNS_XREALLOC(option_list->_options,
+                       ldns_edns_option *, cap);
+               if (new_list) {
+                       option_list->_options = new_list;
+               }
+               /* if the realloc fails, the capacity for the list remains unchanged */
        }
 
-       /* shrink the total EDNS size if the popped EDNS option exists */
+       /* shrink the total EDNS size of the options if the popped EDNS option exists */
        if (pop != NULL) {
                option_list->_options_size -= (ldns_edns_get_size(pop) + 4);
        }

diff --git a/ldns/edns.h b/ldns/edns.h
index b121581c16d133a20c26b1ae7e6a6cbd22f65b25..553b34478efe02cc69ca5a14a94b19cf65eda429 100644 (file)
--- a/ldns/edns.h
+++ b/ldns/edns.h
@@ -108,6 +108,7 @@ typedef struct ldns_struct_edns_option ldns_edns_option;
 struct ldns_struct_edns_option_list
 {
        size_t _option_count; /* the number of EDNS options in the list */
+   size_t _option_capacity; /* the amount of options that fit into the list */
        size_t _options_size; /* the total size of the options serialized */
        ldns_edns_option **_options;
 };