From 9e9737413159e150122872dcad5b77af28a8f7fa Mon Sep 17 00:00:00 2001
From: Mirek Kratochvil <exa.exa@gmail.com>
Date: Thu, 5 Apr 2012 13:52:42 +0200
Subject: [PATCH] goppa generator matrix

---
 include/codecrypt.h | 10 ++++++----
 lib/matrix.cpp      | 29 +++++++++++++++++++++++++----
 lib/permutation.cpp |  8 ++++----
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/include/codecrypt.h b/include/codecrypt.h
index 6669479..48dcba8 100644
--- a/include/codecrypt.h
+++ b/include/codecrypt.h
@@ -74,7 +74,9 @@ public:
 	void unit (uint);
 	bool get_left_square (matrix&);
 	bool strip_left_square (matrix&);
+	void extend_left_compact (matrix&);
 	bool goppa_systematic_form (matrix&, permutation&, prng&);
+	bool goppa_systematic_form (matrix&, const permutation&);
 };
 
 /*
@@ -86,12 +88,12 @@ class permutation : public std::vector<uint>
 protected:
 	_ccr_declare_vector_item
 public:
-	void compute_inversion (permutation&);
+	void compute_inversion (permutation&) const;
 
 	void generate_random (uint n, prng&);
-	void permute (const bvector&, bvector&);
-	void permute (const matrix&, matrix&);
-	void permute_rows (const matrix&, matrix&);
+	void permute (const bvector&, bvector&) const;
+	void permute (const matrix&, matrix&) const;
+	void permute_rows (const matrix&, matrix&) const;
 };
 
 /*
diff --git a/lib/matrix.cpp b/lib/matrix.cpp
index f44b695..b8b0e29 100644
--- a/lib/matrix.cpp
+++ b/lib/matrix.cpp
@@ -127,16 +127,37 @@ bool matrix::strip_left_square (matrix&r)
 	return true;
 }
 
-bool matrix::goppa_systematic_form (matrix&m, permutation&p, prng&rng)
+void matrix::extend_left_compact (matrix&r)
+{
+	uint i;
+	uint h = height(), w = width();
+	r.resize (h + w);
+	for (i = 0; i < h; ++i) {
+		r[i].resize (h, 0);
+		r[i][i] = 1;
+	}
+	for (i = 0; i < w; ++i) {
+		r[h+i] = item (i);
+	}
+}
+
+bool matrix::goppa_systematic_form (matrix&g, permutation&p, prng&rng)
+{
+	p.generate_random (width(), rng);
+	return goppa_systematic_form (g, p);
+}
+
+bool matrix::goppa_systematic_form (matrix&g, const permutation&p)
 {
 	matrix t, sinv, s;
 
-	p.generate_random (width(), rng);
 	p.permute (*this, t);
 	t.get_left_square (sinv);
 	if (!sinv.compute_inversion (s) ) return false; //meant to be retried.
 
 	s.mult (t);
-	s.strip_left_square (m);
-	return 0;
+	s.strip_left_square (t); //matrix pingpong. optimize it.
+	t.compute_transpose (s);
+	s.extend_left_compact (g);
+	return true;
 }
diff --git a/lib/permutation.cpp b/lib/permutation.cpp
index 53dd303..253b5ad 100644
--- a/lib/permutation.cpp
+++ b/lib/permutation.cpp
@@ -3,7 +3,7 @@
 
 using namespace ccr;
 
-void permutation::compute_inversion (permutation&r)
+void permutation::compute_inversion (permutation&r) const
 {
 	r.resize (size(), 0);
 	for (uint i = 0; i < size(); ++i)
@@ -27,19 +27,19 @@ void permutation::generate_random (uint size, prng&rng)
 	}
 }
 
-void permutation::permute (const bvector&a, bvector&r)
+void permutation::permute (const bvector&a, bvector&r) const
 {
 	r.resize (a.size() );
 	for (uint i = 0; i < size(); ++i) r[item (i) ] = a[i];
 }
 
-void permutation::permute (const matrix&a, matrix&r)
+void permutation::permute (const matrix&a, matrix&r) const
 {
 	r.resize (a.size() );
 	for (uint i = 0; i < size(); ++i) r[item (i) ] = a[i];
 }
 
-void permutation::permute_rows (const matrix&a, matrix&r)
+void permutation::permute_rows (const matrix&a, matrix&r) const
 {
 	r.resize (a.size() );
 	for (uint i = 0; i < a.size(); ++i) permute (a[i], r[i]);