From 8b164ba17f6077d8c4adf801a6806b24e2830e59 Mon Sep 17 00:00:00 2001
From: Steven Franke <s.j.franke@icloud.com>
Date: Thu, 22 Mar 2018 14:18:14 +0000
Subject: [PATCH] Add crc14.cpp

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8584 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
---
 lib/crc.f90   | 17 +++++++++++++++++
 lib/crc14.cpp | 31 +++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 lib/crc14.cpp

diff --git a/lib/crc.f90 b/lib/crc.f90
index 6e5c262eb..423f54923 100644
--- a/lib/crc.f90
+++ b/lib/crc.f90
@@ -1,6 +1,23 @@
 module crc 
   use, intrinsic :: iso_c_binding, only: c_int, c_loc, c_int8_t, c_bool, c_short
   interface
+
+    function crc14 (data, length) bind (C, name="crc14")
+      use, intrinsic :: iso_c_binding, only: c_short, c_ptr, c_int
+      implicit none
+      integer (c_short) :: crc14
+      type (c_ptr), value :: data
+      integer (c_int), value :: length
+    end function crc14
+ 
+    function crc14_check (data, length) bind (C, name="crc16_check")
+      use, intrinsic :: iso_c_binding, only: c_bool, c_ptr, c_int
+      implicit none
+      logical (c_bool) :: crc14_check
+      type (c_ptr), value :: data
+      integer (c_int), value :: length
+    end function crc14_check
+
     function crc12 (data, length) bind (C, name="crc12")
       use, intrinsic :: iso_c_binding, only: c_short, c_ptr, c_int
       implicit none
diff --git a/lib/crc14.cpp b/lib/crc14.cpp
new file mode 100644
index 000000000..19a9ba55b
--- /dev/null
+++ b/lib/crc14.cpp
@@ -0,0 +1,31 @@
+#include <boost/crc.hpp>
+#include <boost/config.hpp>
+
+extern "C"
+{
+   short crc14 (unsigned char const * data, int length);
+   bool crc14_check (unsigned char const * data, int length);
+}
+
+#define POLY 0x2757
+
+#ifdef BOOST_NO_CXX11_CONSTEXPR
+#define TRUNCATED_POLYNOMIAL POLY
+#else
+namespace
+{
+  unsigned long constexpr TRUNCATED_POLYNOMIAL = POLY;
+}
+#endif
+
+// assumes CRC is last 14 bits of the data and is set to zero
+// caller should assign the returned CRC into the message in big endian byte order
+short crc14 (unsigned char const * data, int length)
+{
+    return boost::augmented_crc<14, TRUNCATED_POLYNOMIAL> (data, length);
+}
+
+bool crc14_check (unsigned char const * data, int length)
+{
+   return !boost::augmented_crc<14, TRUNCATED_POLYNOMIAL> (data, length);
+}