add delete_key to hash tablewq

Author: xtaci

include/hash_table.h

@@ -19,6 +19,7 @@
 
 #include <stdint.h>
 #include <limits.h>
+#include <stdexcept>
 #include "double_linked_list.h"
 #include "hash_multi.h"
 
@@ -94,6 +95,26 @@ namespace alg
 }
 return false;
 }
+
+/**
+ * delete by key
+ */
+bool delete_key(uint32_t key)
+{
+// hash the key using a hash function.
+uint32_t hash = multi_hash(m_multi, key);
+
+HashKV * kv, *nkv;
+list_for_each_entry_safe(kv,nkv,&m_slots[hash], node) {
+if (kv->key == key) {
+list_del(&kv->node);
+delete kv;
+return true;
+}
+}
+
+return false;
+}
 
 // const version of operator []
 const T& operator[] (uint32_t key) const
@@ -127,7 +148,7 @@ namespace alg
 
 void clear()
 {
-struct HashKV * kv, *nkv;
+HashKV * kv, *nkv;
 for (uint32_t i=0;i<m_size;i++) {
 list_for_each_entry_safe(kv,nkv,&m_slots[i], node){
 list_del(&kv->node);

src/hash_table_demo.cpp

@@ -24,5 +24,13 @@ int main()
 printf("getting %d->%d\n", i, ht[i]);
 }
 
+for(i = 0; i < MAX_ELEMENTS; i++ ){
+printf("deleting %d\n", ht.delete_key(i));
+}
+
+for(i = 0; i < MAX_ELEMENTS; i++ ){
+printf("testing %d->%s\n", i, ht.contains(i)?"true":"false");
+}
+
 return 0;
 }