1 files changed, 114 insertions, 0 deletions
diff --git a/src/libutil/aterm-map.hh b/src/libutil/aterm-map.hh
new file mode 100644
index 000000000..d7aed2ca2
--- /dev/null
+++ b/src/libutil/aterm-map.hh
@@ -0,0 +1,114 @@
+#ifndef __ATERM_MAP_H
+#define __ATERM_MAP_H
+
+#include <aterm2.h>
+#include <assert.h>
+
+using namespace std;
+
+
+class ATermMap
+{
+public:
+
+    struct KeyValue
+    {
+        ATerm key;
+        ATerm value;
+    };
+
+private:
+
+    /* Hash table for the map.  We use open addressing, i.e., all
+       key/value pairs are stored directly in the table, and there are
+       no pointers.  Collisions are resolved through probing. */
+    KeyValue * hashTable;
+
+    /* Current size of the hash table. */
+    unsigned int capacity;
+
+    /* Number of elements in the hash table. */
+    unsigned int count;
+
+    /* Maximum number of elements in the hash table.  If `count'
+       exceeds this number, the hash table is expanded. */
+    unsigned int maxCount;
+    
+public:
+
+    /* Create a map.  `expectedCount' is the number of elements the
+       map is expected to hold. */
+    ATermMap(unsigned int expectedCount);
+    
+    ATermMap(const ATermMap & map);
+    
+    ~ATermMap();
+
+    ATermMap & operator = (const ATermMap & map);
+        
+    void set(ATerm key, ATerm value);
+
+    ATerm get(ATerm key) const;
+
+    void remove(ATerm key);
+
+    unsigned int size();
+
+    struct const_iterator
+    {
+        const ATermMap & map;
+        unsigned int pos;
+        const_iterator(const ATermMap & map, int pos) : map(map)
+        {
+            this->pos = pos;
+        }
+        bool operator !=(const const_iterator & i)
+        {
+            return pos != i.pos;
+        }
+        void operator ++()
+        {
+            if (pos == map.capacity) return;
+            do { ++pos; 
+            } while (pos < map.capacity && map.hashTable[pos].value == 0);
+        }
+        const KeyValue & operator *()
+        {
+            assert(pos < map.capacity);
+            return map.hashTable[pos];
+        }
+        const KeyValue * operator ->()
+        {
+            assert(pos < map.capacity);
+            return &map.hashTable[pos];
+        }
+    };
+
+    const_iterator begin() const
+    {
+        unsigned int i = 0;
+        while (i < capacity && hashTable[i].value == 0) ++i;
+        return const_iterator(*this, i);
+    }
+    
+    const_iterator end() const
+    {
+        return const_iterator(*this, capacity);
+    }
+
+private:
+    
+    void init(unsigned int expectedCount);
+
+    void free();
+
+    void resizeTable(unsigned int expectedCount);
+
+    void copy(KeyValue * elements, unsigned int capacity);
+    
+    inline unsigned int hash1(ATerm key) const;
+    inline unsigned int hash2(ATerm key) const;
+};
+
+
+#endif /* !__ATERM_MAP_H */