From 8b0d4b647a3ac2e21e6a8e7a902eea3ae462e213 Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Fri, 7 Jun 2019 10:14:51 +0200
Subject: Work on STI-D/EDI input

---
 lib/ReedSolomon.cpp | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 lib/ReedSolomon.cpp

(limited to 'lib/ReedSolomon.cpp')

diff --git a/lib/ReedSolomon.cpp b/lib/ReedSolomon.cpp
new file mode 100644
index 0000000..38d8ea8
--- /dev/null
+++ b/lib/ReedSolomon.cpp
@@ -0,0 +1,116 @@
+/*
+   Copyright (C) 2005, 2006, 2007, 2008, 2009 Her Majesty the Queen in Right
+   of Canada (Communications Research Center Canada)
+
+   Copyright (C) 2016
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+    http://www.opendigitalradio.org
+   */
+/*
+   This file is part of ODR-DabMux.
+
+   ODR-DabMux 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 3 of the
+   License, or (at your option) any later version.
+
+   ODR-DabMux 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 ODR-DabMux.  If not, see <http://www.gnu.org/licenses/>.
+   */
+
+#include "ReedSolomon.h"
+#include <vector>
+#include <algorithm>
+#include <stdexcept>
+#include <sstream>
+#include <stdio.h>          // For galois.h ...
+#include <string.h>         // For memcpy
+
+extern "C" {
+#include "fec/fec.h"
+}
+#include <assert.h>
+
+#define SYMSIZE     8
+
+
+ReedSolomon::ReedSolomon(int N, int K, bool reverse, int gfpoly, int firstRoot, int primElem)
+{
+    setReverse(reverse);
+
+    m_N = N;
+    m_K = K;
+
+    const int symsize = SYMSIZE;
+    const int nroots = N - K; // For EDI PFT, this must be 48
+    const int pad = ((1 << symsize) - 1) - N; // is 255-N
+
+    rsData = init_rs_char(symsize, gfpoly, firstRoot, primElem, nroots, pad);
+
+    if (rsData == nullptr) {
+        std::stringstream ss;
+        ss << "Invalid Reed-Solomon parameters! " <<
+            "N=" << N << " ; K=" << K << " ; pad=" << pad;
+        throw std::invalid_argument(ss.str());
+    }
+}
+
+
+ReedSolomon::~ReedSolomon()
+{
+    free_rs_char(rsData);
+}
+
+
+void ReedSolomon::setReverse(bool state)
+{
+    reverse = state;
+}
+
+
+int ReedSolomon::encode(void* data, void* fec, size_t size)
+{
+    uint8_t* input = reinterpret_cast<uint8_t*>(data);
+    uint8_t* output = reinterpret_cast<uint8_t*>(fec);
+    int ret = 0;
+
+    if (reverse) {
+        std::vector<uint8_t> buffer(m_N);
+
+        memcpy(&buffer[0], input, m_K);
+        memcpy(&buffer[m_K], output, m_N - m_K);
+
+        ret = decode_rs_char(rsData, &buffer[0], nullptr, 0);
+        if ((ret != 0) && (ret != -1)) {
+            memcpy(input, &buffer[0], m_K);
+            memcpy(output, &buffer[m_K], m_N - m_K);
+        }
+    }
+    else {
+        encode_rs_char(rsData, input, output);
+    }
+
+    return ret;
+}
+
+
+int ReedSolomon::encode(void* data, size_t size)
+{
+    uint8_t* input = reinterpret_cast<uint8_t*>(data);
+    int ret = 0;
+
+    if (reverse) {
+        ret = decode_rs_char(rsData, input, nullptr, 0);
+    }
+    else {
+        encode_rs_char(rsData, input, &input[m_K]);
+    }
+
+    return ret;
+}
-- 
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