Add T4 bit map compression routines

Add bit map encoder and decoder functions: decoder is fully functional
while encoder is good enough for testing - no backtracking to find
the best possible compression is implemented. If somebody is willing to
implement MS side of EDGE than this has to be expanded.
Add corresponding tests.
N. B: the encoding is implemented according to ETSI TS 44.060 which is
slightly different from T4 used for fax according to CCITT G31D (RFC 804).

Ticket: OW#2407
Sponsored-by: On-Waves ehf

Signed-off-by: Max <msuraev@sysmocom.de>

1 files changed, 42 insertions, 0 deletions

diff --git a/include/osmocom/core/bitcomp.h b/include/osmocom/core/bitcomp.h
new file mode 100644
index 00000000..89eccbce
--- /dev/null
+++ b/include/osmocom/core/bitcomp.h
@@ -0,0 +1,42 @@
+#pragma once
+
+/* bit compression routines */
+
+/* (C) 2016 sysmocom s.f.m.c. GmbH by Max Suraev <msuraev@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+/*! \defgroup bitcomp Bit compression
+ *  @{
+ */
+
+/*! \file bitcomp.h
+ *  \brief Osmocom bit compression routines
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <osmocom/core/bitvec.h>
+
+
+int osmo_t4_encode(struct bitvec *bv);
+int osmo_t4_decode(const struct bitvec *in, bool cc, struct bitvec *out);
+
+/*! @} */