bvector: string/bvector conversion utility

src/bvector.cpp

@@ -113,6 +113,28 @@ void bvector::from_poly_cotrace (const polynomial&r, gf2m&fld)
 		item (i) = (r[i % s] >> (i / s) ) & 1;
 }
 
+bool bvector::to_string (std::string& out) const
+{
+	if (size() & 0x7) return false;
+
+	out.clear();
+	out.resize (size() >> 3, 0);
+
+	for (uint i = 0; i < size(); ++i)
+		if (item (i) ) out[i >> 3] |= (1 << (i & 0x7) );
+
+	return true;
+}
+
+void bvector::from_string (const std::string&in)
+{
+	clear();
+	resize (in.length() << 3);
+
+	for (uint i = 0; i < size(); ++i)
+		item (i) = (in[i >> 3] >> (i & 0x7) ) & 1;
+}
+
 /*
  * utility colex (un)ranking for niederreiter and workalikes.
  * see Ruskey's Combinatorial Generation, algorithm 4.10

src/bvector.h

@@ -20,6 +20,7 @@
 #define _ccr_bvector_h_
 
 #include <vector>
+#include <string>
 #include "types.h"
 #include "vector_item.h"
 #include "sencode.h"
@@ -56,6 +57,9 @@ public:
 	void colex_rank (bvector&) const;
 	void colex_unrank (bvector&, uint n, uint k) const;
 
+	bool to_string (std::string&) const;
+	void from_string (const std::string&);
+
 	sencode* serialize();
 	bool unserialize (sencode*);
 };