Cube from string

docs/changelog.rst

@@ -7,8 +7,9 @@ v0.3 (not yet released)
 * Constructors: ``create_from_chain``
   `#28 <https://github.com/msoeken/kitty/pull/28>`_
 
-* Cube constructors: ``pos_cube``, ``neg_cube``
+* Cube constructors: ``pos_cube``, ``neg_cube``, constructor to create cube from string
   `#29 <https://github.com/msoeken/kitty/pull/29>`_
+  `#31 <https://github.com/msoeken/kitty/pull/31>`_
 
 * Cube methods: ``get_bit``, ``get_mask``, ``set_bit``, ``set_mask``, ``clear_bit``, ``clear_mask`` (contributed by Heinz Riener)
   `#30 <https://github.com/msoeken/kitty/pull/30>`_

docs/cube.rst

@@ -16,6 +16,8 @@ member functions.
 +--------------------------------------+-------------------------------------------------------------------------+
 | ``cube(bits, mask)``                 | Constructs a cube from bits and mask                                    |
 +--------------------------------------+-------------------------------------------------------------------------+
+| ``cube(str)``                        | Constructs a cube from a string                                         |
++--------------------------------------+-------------------------------------------------------------------------+
 | ``num_literals()``                   | Returns number of literals                                              |
 +--------------------------------------+-------------------------------------------------------------------------+
 | ``distance(that)``                   | Returns the distance to another cube                                    |
@@ -52,3 +54,6 @@ member functions.
 +--------------------------------------+-------------------------------------------------------------------------+
 
 You can use ``kitty::hash<cube>`` to hash cubes, e.g., in a hash map or set.
+
+.. doxygenclass:: kitty::cube
+   :members:

include/kitty/cube.hpp

@@ -34,6 +34,7 @@
 
 #include <functional>
 #include <iostream>
+#include <string>
 
 #include "hash.hpp"
 
@@ -59,6 +60,40 @@ class cube
   */
   cube( uint32_t bits, uint32_t mask ) : _bits( bits ), _mask( mask ) {}
 
+  /*! \brief Constructs a cube from a string
+
+    Each character corresponds to one literal in the cube.  Only up to first 32
+    characters of the string will be considered, since this data structure
+    cannot represent cubes with more than 32 literals.  A '1' in the string
+    corresponds to a postive literal, a '0' corresponds to a negative literal.
+    All other characters represent don't care, but it is customary to use '-'.
+
+    \param str String representing a cube
+  */
+  explicit cube( const std::string& str )
+  {
+    _bits = _mask = 0u;
+
+    auto p = str.begin();
+
+    for ( uint64_t i = 1; i <= ( uint64_t( 1u ) << 32u ); i <<= 1 )
+    {
+      switch ( *p )
+      {
+        default: /* don't care */
+          break;
+        case '1':
+          _bits |= i;
+          /* no break on purpose, jump to 0 and set mask */
+        case '0':
+          _mask |= i;
+          break;
+      }
+
+      if ( ++p == str.end() ) return;
+    }
+  }
+
   /*! \brief Returns number of literals */
   inline int num_literals() const
   {

test/cube.cpp

@@ -53,6 +53,17 @@ TEST_F( CubeTest, constructing_and_printing )
   EXPECT_EQ( to_string( cube( 0, 2 ), 2 ), "-0" );
 }
 
+TEST_F( CubeTest, construction_from_string )
+{
+  EXPECT_EQ( to_string( cube( "010" ), 3 ), "010" );
+  EXPECT_EQ( to_string( cube( "-1-" ), 3 ), "-1-" );
+  EXPECT_EQ( to_string( cube( "*00" ), 3 ), "-00" );
+
+  EXPECT_EQ( to_string( cube( "" ), 0 ), "" );
+  EXPECT_EQ( to_string( cube( std::string( 32, '1' ) ), 32 ), std::string( 32, '1' ) ); 
+  EXPECT_EQ( to_string( cube( std::string( 33, '1' ) ), 32 ), std::string( 32, '1' ) ); 
+}
+
 TEST_F( CubeTest, distance )
 {
   EXPECT_EQ( cube().distance( cube( 0, 2 ) ), 1 );