reorganizing the code

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/ast/substitution/var_offset_map.h

@@ -0,0 +1,114 @@
+/*++
+Copyright (c) 2006 Microsoft Corporation
+
+Module Name:
+
+    var_offset_map.h
+
+Abstract:
+
+    A generic mapping from (var, offset) to a value T.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2008-02-01.
+
+Revision History:
+
+--*/
+#ifndef _VAR_OFFSET_MAP_H_
+#define _VAR_OFFSET_MAP_H_
+
+#include"ast.h"
+#include"vector.h"
+
+/**
+   \brief A mapping from variable-id + offset to some value of type T.
+*/
+template<typename T>
+class var_offset_map {
+protected:
+    struct data {
+        T        m_data;
+        unsigned m_timestamp;
+        data():m_timestamp(0) {}
+    };
+    
+    svector<data>           m_map;
+    unsigned                m_num_offsets;
+    unsigned                m_num_vars;
+    unsigned                m_timestamp;
+
+public:
+    var_offset_map():
+        m_num_offsets(0),
+        m_num_vars(0),
+        m_timestamp(1) {
+    }
+
+    void reset() {
+        m_timestamp++;
+        if (m_timestamp == UINT_MAX) {
+            typename svector<data>::iterator it  = m_map.begin();
+            typename svector<data>::iterator end = m_map.end();
+            for (; it != end; ++it)
+                it->m_timestamp = 0;
+            m_timestamp = 1;
+        }
+    }
+
+    unsigned offsets_capacity() const { return m_num_offsets; }
+
+    unsigned vars_capacity() const { return m_num_vars; }
+
+    void reserve(unsigned num_offsets, unsigned num_vars) {
+        if (num_offsets > m_num_offsets || num_vars > m_num_vars) {
+            unsigned sz = num_offsets * num_vars;
+            m_map.resize(sz);
+            m_num_vars    = num_vars;
+            m_num_offsets = num_offsets;
+        }
+        reset();
+    }
+
+    void reserve_offsets(unsigned num_offsets) { reserve(num_offsets, m_num_vars); }
+
+    void reserve_vars(unsigned num_vars) { reserve(m_num_offsets, num_vars); }
+
+    void insert(unsigned v_idx, unsigned offset, T const & t) {
+        SASSERT(v_idx < m_num_vars);
+        SASSERT(offset < m_num_offsets);
+        unsigned idx  = v_idx + offset * m_num_vars;
+        SASSERT(idx < m_map.size());
+        data & d = m_map[idx];
+        d.m_data      = t;
+        d.m_timestamp = m_timestamp;
+    }
+
+    void insert(var * v, unsigned offset, T const & t) { insert(v->get_idx(), offset, t); }
+    
+    bool find(unsigned v_idx, unsigned offset, T & r) const {
+        SASSERT(v_idx < m_num_vars);
+        SASSERT(offset < m_num_offsets);
+        unsigned idx  = v_idx + offset * m_num_vars;
+        data const & d = m_map[idx];
+        SASSERT(d.m_timestamp <= m_timestamp);
+        if (d.m_timestamp == m_timestamp) {
+            r = d.m_data;
+            return true;
+        }
+        return false;
+    }
+    
+    bool find(var * v, unsigned offset, T & r) const { return find(v->get_idx(), offset, r); }
+
+    void erase(unsigned v_idx, unsigned offset) {
+        SASSERT(v_idx < m_num_vars);
+        SASSERT(offset < m_num_offsets);
+        unsigned idx  = v_idx + offset * m_num_vars;
+        m_map[idx].m_timestamp = 0;
+    }
+
+};
+
+#endif /* _VAR_OFFSET_MAP_H_ */