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authorMatthias P. Braendli <matthias.braendli@mpb.li>2016-11-19 10:28:24 +0100
committerMatthias P. Braendli <matthias.braendli@mpb.li>2016-11-19 10:28:24 +0100
commita9a7fcc7c3baea55846109f67973046b6ef39881 (patch)
tree79086d2e9c5f71f6d193c352447cf5a331099912
parent5ef0faf4b50df9ec99304732880a74c08f575e79 (diff)
downloadodr-edilib-a9a7fcc7c3baea55846109f67973046b6ef39881.tar.gz
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Replace libfec dependency by copy of fec code
-rw-r--r--.gitignore7
-rw-r--r--.ycm_extra_conf.py72
-rw-r--r--CMakeLists.txt23
-rw-r--r--ReedSolomon.cpp51
-rw-r--r--ReedSolomon.h30
-rw-r--r--cmake/Modules/FindFec.cmake34
-rw-r--r--fec/LICENSE502
-rw-r--r--fec/README.md12
-rw-r--r--fec/char.h24
-rw-r--r--fec/decode_rs.h298
-rw-r--r--fec/decode_rs_char.c22
-rw-r--r--fec/encode_rs.h58
-rw-r--r--fec/encode_rs_char.c15
-rw-r--r--fec/fec.h30
-rw-r--r--fec/init_rs.h104
-rw-r--r--fec/init_rs_char.c35
-rw-r--r--fec/rs-common.h26
-rw-r--r--test/main.cpp2
18 files changed, 1199 insertions, 146 deletions
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4025fde
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,7 @@
+CMakeCache.txt
+CMakeFiles/
+Makefile
+blub.eti
+cmake_install.cmake
+cmake_uninstall.cmake
+edilib
diff --git a/.ycm_extra_conf.py b/.ycm_extra_conf.py
index d799975..ff9a626 100644
--- a/.ycm_extra_conf.py
+++ b/.ycm_extra_conf.py
@@ -2,8 +2,6 @@
import os
import ycm_core
-# These are the compilation flags that will be used in case there's no
-# compilation database set (by default, one is not set).
# CHANGE THIS LIST OF FLAGS. YES, THIS IS THE DROID YOU HAVE BEEN LOOKING FOR.
flags = [
'-std=c++11',
@@ -13,29 +11,9 @@ flags = [
]
-# Set this to the absolute path to the folder (NOT the file!) containing the
-# compile_commands.json file to use that instead of 'flags'. See here for
-# more details: http://clang.llvm.org/docs/JSONCompilationDatabase.html
-#
-# You can get CMake to generate this file for you by adding:
-# set( CMAKE_EXPORT_COMPILE_COMMANDS 1 )
-# to your CMakeLists.txt file.
-#
-# Most projects will NOT need to set this to anything; you can just change the
-# 'flags' list of compilation flags. Notice that YCM itself uses that approach.
-compilation_database_folder = ''
-
-if os.path.exists( compilation_database_folder ):
- database = ycm_core.CompilationDatabase( compilation_database_folder )
-else:
- database = None
-
-SOURCE_EXTENSIONS = [ '.cpp', '.cxx', '.cc', '.c', '.m', '.mm' ]
-
def DirectoryOfThisScript():
return os.path.dirname( os.path.abspath( __file__ ) )
-
def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):
if not working_directory:
return list( flags )
@@ -64,54 +42,16 @@ def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):
new_flags.append( new_flag )
return new_flags
-
-def IsHeaderFile( filename ):
- extension = os.path.splitext( filename )[ 1 ]
- return extension in [ '.h', '.hxx', '.hpp', '.hh' ]
-
-
-def GetCompilationInfoForFile( filename ):
- # The compilation_commands.json file generated by CMake does not have entries
- # for header files. So we do our best by asking the db for flags for a
- # corresponding source file, if any. If one exists, the flags for that file
- # should be good enough.
- if IsHeaderFile( filename ):
- basename = os.path.splitext( filename )[ 0 ]
- for extension in SOURCE_EXTENSIONS:
- replacement_file = basename + extension
- if os.path.exists( replacement_file ):
- compilation_info = database.GetCompilationInfoForFile(
- replacement_file )
- if compilation_info.compiler_flags_:
- return compilation_info
- return None
- return database.GetCompilationInfoForFile( filename )
-
-
def FlagsForFile( filename, **kwargs ):
- if database:
- # Bear in mind that compilation_info.compiler_flags_ does NOT return a
- # python list, but a "list-like" StringVec object
- compilation_info = GetCompilationInfoForFile( filename )
- if not compilation_info:
- return None
+ relative_to = DirectoryOfThisScript()
+ final_flags = MakeRelativePathsInFlagsAbsolute( flags, relative_to )
- final_flags = MakeRelativePathsInFlagsAbsolute(
- compilation_info.compiler_flags_,
- compilation_info.compiler_working_dir_ )
-
- # NOTE: This is just for YouCompleteMe; it's highly likely that your project
- # does NOT need to remove the stdlib flag. DO NOT USE THIS IN YOUR
- # ycm_extra_conf IF YOU'RE NOT 100% SURE YOU NEED IT.
- try:
- final_flags.remove( '-stdlib=libc++' )
- except ValueError:
- pass
- else:
- relative_to = DirectoryOfThisScript()
- final_flags = MakeRelativePathsInFlagsAbsolute( flags, relative_to )
+ if filename.endswith(".h"):
+ final_flags += "-x c++".split()
return {
'flags': final_flags,
'do_cache': True
}
+
+ }
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1eff757..caee500 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@
########################################################################
cmake_minimum_required(VERSION 2.8)
-project(edilib CXX)
+project(edilib CXX C)
# Select the release build type by default to get optimization flags
if(NOT CMAKE_BUILD_TYPE)
@@ -32,10 +32,6 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -W -Wall -std=c++11")
# Find build dependencies
########################################################################
-# libfec
-find_package(Fec REQUIRED)
-include_directories(${FEC_INCLUDE_DIRS})
-
########################################################################
# Setup apps
########################################################################
@@ -43,18 +39,25 @@ include_directories(${FEC_INCLUDE_DIRS})
include_directories("./decoder")
include_directories(".")
-list(APPEND edilib_sources
+list(APPEND edilib_cpp_sources
ReedSolomon.cpp
- crc.c
decoder/EDIDecoder.cpp
decoder/ETIWriter.cpp
decoder/eti.cpp
test/main.cpp
)
-set_source_files_properties(${edilib_sources} PROPERTIES LANGUAGE "CXX")
-add_executable(edilib ${edilib_sources})
-target_link_libraries(edilib ${FAAD_LIBRARIES} ${FEC_LIBRARIES})
+list(APPEND edilib_c_sources
+ crc.c
+ fec/decode_rs_char.c
+ fec/encode_rs_char.c
+ fec/init_rs_char.c
+)
+
+set_source_files_properties(${edilib_cpp_sources} PROPERTIES LANGUAGE "CXX")
+set_source_files_properties(${edilib_c_sources} PROPERTIES LANGUAGE "C")
+add_executable(edilib ${edilib_cpp_sources} ${edilib_c_sources})
+target_link_libraries(edilib ${FAAD_LIBRARIES})
install(TARGETS edilib DESTINATION bin)
diff --git a/ReedSolomon.cpp b/ReedSolomon.cpp
index c72fb14..38d8ea8 100644
--- a/ReedSolomon.cpp
+++ b/ReedSolomon.cpp
@@ -1,6 +1,11 @@
/*
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.
@@ -20,16 +25,17 @@
*/
#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.h>
+#include "fec/fec.h"
}
#include <assert.h>
-#include <stdlib.h>
#define SYMSIZE 8
@@ -38,8 +44,8 @@ ReedSolomon::ReedSolomon(int N, int K, bool reverse, int gfpoly, int firstRoot,
{
setReverse(reverse);
- myN = N;
- myK = K;
+ m_N = N;
+ m_K = K;
const int symsize = SYMSIZE;
const int nroots = N - K; // For EDI PFT, this must be 48
@@ -47,7 +53,7 @@ ReedSolomon::ReedSolomon(int N, int K, bool reverse, int gfpoly, int firstRoot,
rsData = init_rs_char(symsize, gfpoly, firstRoot, primElem, nroots, pad);
- if (rsData == NULL) {
+ if (rsData == nullptr) {
std::stringstream ss;
ss << "Invalid Reed-Solomon parameters! " <<
"N=" << N << " ; K=" << K << " ; pad=" << pad;
@@ -68,25 +74,25 @@ void ReedSolomon::setReverse(bool state)
}
-int ReedSolomon::encode(void* data, void* fec, unsigned long size)
+int ReedSolomon::encode(void* data, void* fec, size_t size)
{
- unsigned char* input = reinterpret_cast<unsigned char*>(data);
- unsigned char* output = reinterpret_cast<unsigned char*>(fec);
+ uint8_t* input = reinterpret_cast<uint8_t*>(data);
+ uint8_t* output = reinterpret_cast<uint8_t*>(fec);
int ret = 0;
if (reverse) {
- unsigned char* buffer = new unsigned char[myN];
- memcpy(buffer, input, myK);
- memcpy(&buffer[myK], output, myN - myK);
+ 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, NULL, 0);
+ ret = decode_rs_char(rsData, &buffer[0], nullptr, 0);
if ((ret != 0) && (ret != -1)) {
- memcpy(input, buffer, myK);
- memcpy(output, &buffer[myK], myN - myK);
+ memcpy(input, &buffer[0], m_K);
+ memcpy(output, &buffer[m_K], m_N - m_K);
}
-
- delete[] buffer;
- } else {
+ }
+ else {
encode_rs_char(rsData, input, output);
}
@@ -94,15 +100,16 @@ int ReedSolomon::encode(void* data, void* fec, unsigned long size)
}
-int ReedSolomon::encode(void* data, unsigned long size)
+int ReedSolomon::encode(void* data, size_t size)
{
- unsigned char* input = reinterpret_cast<unsigned char*>(data);
+ uint8_t* input = reinterpret_cast<uint8_t*>(data);
int ret = 0;
if (reverse) {
- ret = decode_rs_char(rsData, input, NULL, 0);
- } else {
- encode_rs_char(rsData, input, &input[myK]);
+ ret = decode_rs_char(rsData, input, nullptr, 0);
+ }
+ else {
+ encode_rs_char(rsData, input, &input[m_K]);
}
return ret;
diff --git a/ReedSolomon.h b/ReedSolomon.h
index d96a522..abcef62 100644
--- a/ReedSolomon.h
+++ b/ReedSolomon.h
@@ -1,6 +1,11 @@
/*
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.
@@ -19,34 +24,33 @@
along with ODR-DabMux. If not, see <http://www.gnu.org/licenses/>.
*/
-#ifndef _REEDSOLOMON
-#define _REEDSOLOMON
+#pragma once
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
+#include <stdlib.h>
class ReedSolomon
{
public:
- ReedSolomon(int N, int K, bool reverse = false,
+ ReedSolomon(int N, int K,
+ bool reverse = false,
int gfpoly = 0x11d, int firstRoot = 0, int primElem = 1);
- ReedSolomon(const ReedSolomon& clone);
- virtual ~ReedSolomon();
+ ReedSolomon(const ReedSolomon& other) = delete;
+ ReedSolomon operator=(const ReedSolomon& other) = delete;
+ ~ReedSolomon();
void setReverse(bool state);
- int encode(void* data, void* fec, unsigned long size);
- int encode(void* data, unsigned long size);
-
-protected:
- int myN;
- int myK;
+ int encode(void* data, void* fec, size_t size);
+ int encode(void* data, size_t size);
private:
+ int m_N;
+ int m_K;
+
void* rsData;
bool reverse;
};
-
-#endif // _REEDSOLOMON
diff --git a/cmake/Modules/FindFec.cmake b/cmake/Modules/FindFec.cmake
deleted file mode 100644
index 59dc525..0000000
--- a/cmake/Modules/FindFec.cmake
+++ /dev/null
@@ -1,34 +0,0 @@
-# Try to find FEC library and include path.
-# Once done this will define
-#
-# FEC_INCLUDE_DIRS - where to find fec.h, etc.
-# FEC_LIBRARIES - List of libraries when using libFEC.
-# FEC_FOUND - True if libFEC found.
-
-find_path(FEC_INCLUDE_DIR fec.h DOC "The directory where fec.h resides")
-find_library(FEC_LIBRARY NAMES fec DOC "The libFEC library")
-
-if(FEC_INCLUDE_DIR AND FEC_LIBRARY)
- set(FEC_FOUND 1)
- set(FEC_LIBRARIES ${FEC_LIBRARY})
- set(FEC_INCLUDE_DIRS ${FEC_INCLUDE_DIR})
-else(FEC_INCLUDE_DIR AND FEC_LIBRARY)
- set(FEC_FOUND 0)
- set(FEC_LIBRARIES)
- set(FEC_INCLUDE_DIRS)
-endif(FEC_INCLUDE_DIR AND FEC_LIBRARY)
-
-mark_as_advanced(FEC_INCLUDE_DIR)
-mark_as_advanced(FEC_LIBRARY)
-mark_as_advanced(FEC_FOUND)
-
-if(NOT FEC_FOUND)
- set(FEC_DIR_MESSAGE "libfec was not found. Make sure FEC_LIBRARY and FEC_INCLUDE_DIR are set.")
- if(NOT FEC_FIND_QUIETLY)
- message(STATUS "${FEC_DIR_MESSAGE}")
- else(NOT FEC_FIND_QUIETLY)
- if(FEC_FIND_REQUIRED)
- message(FATAL_ERROR "${FEC_DIR_MESSAGE}")
- endif(FEC_FIND_REQUIRED)
- endif(NOT FEC_FIND_QUIETLY)
-endif(NOT FEC_FOUND)
diff --git a/fec/LICENSE b/fec/LICENSE
new file mode 100644
index 0000000..5a883d3
--- /dev/null
+++ b/fec/LICENSE
@@ -0,0 +1,502 @@
+GNU LESSER GENERAL PUBLIC LICENSE
+ Version 2.1, February 1999
+
+ Copyright (C) 1991, 1999 Free Software Foundation, Inc.
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+(This is the first released version of the Lesser GPL. It also counts
+ as the successor of the GNU Library Public License, version 2, hence
+ the version number 2.1.)
+
+ Preamble
+
+ The licenses for most software are designed to take away your
+freedom to share and change it. By contrast, the GNU General Public
+Licenses are intended to guarantee your freedom to share and change
+free software--to make sure the software is free for all its users.
+
+ This license, the Lesser General Public License, applies to some
+specially designated software packages--typically libraries--of the
+Free Software Foundation and other authors who decide to use it. You
+can use it too, but we suggest you first think carefully about whether
+this license or the ordinary General Public License is the better
+strategy to use in any particular case, based on the explanations below.
+
+ When we speak of free software, we are referring to freedom of use,
+not price. Our General Public Licenses are designed to make sure that
+you have the freedom to distribute copies of free software (and charge
+for this service if you wish); that you receive source code or can get
+it if you want it; that you can change the software and use pieces of
+it in new free programs; and that you are informed that you can do
+these things.
+
+ To protect your rights, we need to make restrictions that forbid
+distributors to deny you these rights or to ask you to surrender these
+rights. These restrictions translate to certain responsibilities for
+you if you distribute copies of the library or if you modify it.
+
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+
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+General Public License, applies to certain designated libraries, and
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+That's all there is to it!
diff --git a/fec/README.md b/fec/README.md
new file mode 100644
index 0000000..a44d28d
--- /dev/null
+++ b/fec/README.md
@@ -0,0 +1,12 @@
+FEC routines from KA9Q's libfec
+===============================
+
+This folder contains part of the libfec library by KA9Q. Only the
+char-sized Reed-Solomon encoder and decoder is here.
+
+The files have been copied from the libfec fork at
+https://github.com/Opendigitalradio/ka9q-fec
+
+Original code is at http://www.ka9q.net/code/fec/
+
+All files in this folder are licenced under the LGPL v2.1, please see LICENCE
diff --git a/fec/char.h b/fec/char.h
new file mode 100644
index 0000000..25efd65
--- /dev/null
+++ b/fec/char.h
@@ -0,0 +1,24 @@
+/* Stuff specific to the 8-bit symbol version of the general purpose RS codecs
+ *
+ * Copyright 2003, Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+typedef unsigned char data_t;
+
+#define MODNN(x) modnn(rs,x)
+
+#define MM (rs->mm)
+#define NN (rs->nn)
+#define ALPHA_TO (rs->alpha_to)
+#define INDEX_OF (rs->index_of)
+#define GENPOLY (rs->genpoly)
+#define NROOTS (rs->nroots)
+#define FCR (rs->fcr)
+#define PRIM (rs->prim)
+#define IPRIM (rs->iprim)
+#define PAD (rs->pad)
+#define A0 (NN)
+
+
+
+
diff --git a/fec/decode_rs.h b/fec/decode_rs.h
new file mode 100644
index 0000000..c165cf3
--- /dev/null
+++ b/fec/decode_rs.h
@@ -0,0 +1,298 @@
+/* The guts of the Reed-Solomon decoder, meant to be #included
+ * into a function body with the following typedefs, macros and variables supplied
+ * according to the code parameters:
+
+ * data_t - a typedef for the data symbol
+ * data_t data[] - array of NN data and parity symbols to be corrected in place
+ * retval - an integer lvalue into which the decoder's return code is written
+ * NROOTS - the number of roots in the RS code generator polynomial,
+ * which is the same as the number of parity symbols in a block.
+ Integer variable or literal.
+ * NN - the total number of symbols in a RS block. Integer variable or literal.
+ * PAD - the number of pad symbols in a block. Integer variable or literal.
+ * ALPHA_TO - The address of an array of NN elements to convert Galois field
+ * elements in index (log) form to polynomial form. Read only.
+ * INDEX_OF - The address of an array of NN elements to convert Galois field
+ * elements in polynomial form to index (log) form. Read only.
+ * MODNN - a function to reduce its argument modulo NN. May be inline or a macro.
+ * FCR - An integer literal or variable specifying the first consecutive root of the
+ * Reed-Solomon generator polynomial. Integer variable or literal.
+ * PRIM - The primitive root of the generator poly. Integer variable or literal.
+ * DEBUG - If set to 1 or more, do various internal consistency checking. Leave this
+ * undefined for production code
+
+ * The memset(), memmove(), and memcpy() functions are used. The appropriate header
+ * file declaring these functions (usually <string.h>) must be included by the calling
+ * program.
+ */
+
+
+#if !defined(NROOTS)
+#error "NROOTS not defined"
+#endif
+
+#if !defined(NN)
+#error "NN not defined"
+#endif
+
+#if !defined(PAD)
+#error "PAD not defined"
+#endif
+
+#if !defined(ALPHA_TO)
+#error "ALPHA_TO not defined"
+#endif
+
+#if !defined(INDEX_OF)
+#error "INDEX_OF not defined"
+#endif
+
+#if !defined(MODNN)
+#error "MODNN not defined"
+#endif
+
+#if !defined(FCR)
+#error "FCR not defined"
+#endif
+
+#if !defined(PRIM)
+#error "PRIM not defined"
+#endif
+
+#if !defined(NULL)
+#define NULL ((void *)0)
+#endif
+
+#undef MIN
+#define MIN(a,b) ((a) < (b) ? (a) : (b))
+#undef A0
+#define A0 (NN)
+
+{
+ int deg_lambda, el, deg_omega;
+ int i, j, r,k;
+ data_t u,q,tmp,num1,num2,den,discr_r;
+ data_t lambda[NROOTS+1], s[NROOTS]; /* Err+Eras Locator poly
+ * and syndrome poly */
+ data_t b[NROOTS+1], t[NROOTS+1], omega[NROOTS+1];
+ data_t root[NROOTS], reg[NROOTS+1], loc[NROOTS];
+ int syn_error, count;
+
+ /* form the syndromes; i.e., evaluate data(x) at roots of g(x) */
+ for(i=0;i<NROOTS;i++)
+ s[i] = data[0];
+
+ for(j=1;j<NN-PAD;j++){
+ for(i=0;i<NROOTS;i++){
+ if(s[i] == 0){
+ s[i] = data[j];
+ } else {
+ s[i] = data[j] ^ ALPHA_TO[MODNN(INDEX_OF[s[i]] + (FCR+i)*PRIM)];
+ }
+ }
+ }
+
+ /* Convert syndromes to index form, checking for nonzero condition */
+ syn_error = 0;
+ for(i=0;i<NROOTS;i++){
+ syn_error |= s[i];
+ s[i] = INDEX_OF[s[i]];
+ }
+
+ if (!syn_error) {
+ /* if syndrome is zero, data[] is a codeword and there are no
+ * errors to correct. So return data[] unmodified
+ */
+ count = 0;
+ goto finish;
+ }
+ memset(&lambda[1],0,NROOTS*sizeof(lambda[0]));
+ lambda[0] = 1;
+
+ if (no_eras > 0) {
+ /* Init lambda to be the erasure locator polynomial */
+ lambda[1] = ALPHA_TO[MODNN(PRIM*(NN-1-eras_pos[0]))];
+ for (i = 1; i < no_eras; i++) {
+ u = MODNN(PRIM*(NN-1-eras_pos[i]));
+ for (j = i+1; j > 0; j--) {
+ tmp = INDEX_OF[lambda[j - 1]];
+ if(tmp != A0)
+ lambda[j] ^= ALPHA_TO[MODNN(u + tmp)];
+ }
+ }
+
+#if DEBUG >= 1
+ /* Test code that verifies the erasure locator polynomial just constructed
+ Needed only for decoder debugging. */
+
+ /* find roots of the erasure location polynomial */
+ for(i=1;i<=no_eras;i++)
+ reg[i] = INDEX_OF[lambda[i]];
+
+ count = 0;
+ for (i = 1,k=IPRIM-1; i <= NN; i++,k = MODNN(k+IPRIM)) {
+ q = 1;
+ for (j = 1; j <= no_eras; j++)
+ if (reg[j] != A0) {
+ reg[j] = MODNN(reg[j] + j);
+ q ^= ALPHA_TO[reg[j]];
+ }
+ if (q != 0)
+ continue;
+ /* store root and error location number indices */
+ root[count] = i;
+ loc[count] = k;
+ count++;
+ }
+ if (count != no_eras) {
+ printf("count = %d no_eras = %d\n lambda(x) is WRONG\n",count,no_eras);
+ count = -1;
+ goto finish;
+ }
+#if DEBUG >= 2
+ printf("\n Erasure positions as determined by roots of Eras Loc Poly:\n");
+ for (i = 0; i < count; i++)
+ printf("%d ", loc[i]);
+ printf("\n");
+#endif
+#endif
+ }
+ for(i=0;i<NROOTS+1;i++)
+ b[i] = INDEX_OF[lambda[i]];
+
+ /*
+ * Begin Berlekamp-Massey algorithm to determine error+erasure
+ * locator polynomial
+ */
+ r = no_eras;
+ el = no_eras;
+ while (++r <= NROOTS) { /* r is the step number */
+ /* Compute discrepancy at the r-th step in poly-form */
+ discr_r = 0;
+ for (i = 0; i < r; i++){
+ if ((lambda[i] != 0) && (s[r-i-1] != A0)) {
+ discr_r ^= ALPHA_TO[MODNN(INDEX_OF[lambda[i]] + s[r-i-1])];
+ }
+ }
+ discr_r = INDEX_OF[discr_r]; /* Index form */
+ if (discr_r == A0) {
+ /* 2 lines below: B(x) <-- x*B(x) */
+ memmove(&b[1],b,NROOTS*sizeof(b[0]));
+ b[0] = A0;
+ } else {
+ /* 7 lines below: T(x) <-- lambda(x) - discr_r*x*b(x) */
+ t[0] = lambda[0];
+ for (i = 0 ; i < NROOTS; i++) {
+ if(b[i] != A0)
+ t[i+1] = lambda[i+1] ^ ALPHA_TO[MODNN(discr_r + b[i])];
+ else
+ t[i+1] = lambda[i+1];
+ }
+ if (2 * el <= r + no_eras - 1) {
+ el = r + no_eras - el;
+ /*
+ * 2 lines below: B(x) <-- inv(discr_r) *
+ * lambda(x)
+ */
+ for (i = 0; i <= NROOTS; i++)
+ b[i] = (lambda[i] == 0) ? A0 : MODNN(INDEX_OF[lambda[i]] - discr_r + NN);
+ } else {
+ /* 2 lines below: B(x) <-- x*B(x) */
+ memmove(&b[1],b,NROOTS*sizeof(b[0]));
+ b[0] = A0;
+ }
+ memcpy(lambda,t,(NROOTS+1)*sizeof(t[0]));
+ }
+ }
+
+ /* Convert lambda to index form and compute deg(lambda(x)) */
+ deg_lambda = 0;
+ for(i=0;i<NROOTS+1;i++){
+ lambda[i] = INDEX_OF[lambda[i]];
+ if(lambda[i] != A0)
+ deg_lambda = i;
+ }
+ /* Find roots of the error+erasure locator polynomial by Chien search */
+ memcpy(&reg[1],&lambda[1],NROOTS*sizeof(reg[0]));
+ count = 0; /* Number of roots of lambda(x) */
+ for (i = 1,k=IPRIM-1; i <= NN; i++,k = MODNN(k+IPRIM)) {
+ q = 1; /* lambda[0] is always 0 */
+ for (j = deg_lambda; j > 0; j--){
+ if (reg[j] != A0) {
+ reg[j] = MODNN(reg[j] + j);
+ q ^= ALPHA_TO[reg[j]];
+ }
+ }
+ if (q != 0)
+ continue; /* Not a root */
+ /* store root (index-form) and error location number */
+#if DEBUG>=2
+ printf("count %d root %d loc %d\n",count,i,k);
+#endif
+ root[count] = i;
+ loc[count] = k;
+ /* If we've already found max possible roots,
+ * abort the search to save time
+ */
+ if(++count == deg_lambda)
+ break;
+ }
+ if (deg_lambda != count) {
+ /*
+ * deg(lambda) unequal to number of roots => uncorrectable
+ * error detected
+ */
+ count = -1;
+ goto finish;
+ }
+ /*
+ * Compute err+eras evaluator poly omega(x) = s(x)*lambda(x) (modulo
+ * x**NROOTS). in index form. Also find deg(omega).
+ */
+ deg_omega = deg_lambda-1;
+ for (i = 0; i <= deg_omega;i++){
+ tmp = 0;
+ for(j=i;j >= 0; j--){
+ if ((s[i - j] != A0) && (lambda[j] != A0))
+ tmp ^= ALPHA_TO[MODNN(s[i - j] + lambda[j])];
+ }
+ omega[i] = INDEX_OF[tmp];
+ }
+
+ /*
+ * Compute error values in poly-form. num1 = omega(inv(X(l))), num2 =
+ * inv(X(l))**(FCR-1) and den = lambda_pr(inv(X(l))) all in poly-form
+ */
+ for (j = count-1; j >=0; j--) {
+ num1 = 0;
+ for (i = deg_omega; i >= 0; i--) {
+ if (omega[i] != A0)
+ num1 ^= ALPHA_TO[MODNN(omega[i] + i * root[j])];
+ }
+ num2 = ALPHA_TO[MODNN(root[j] * (FCR - 1) + NN)];
+ den = 0;
+
+ /* lambda[i+1] for i even is the formal derivative lambda_pr of lambda[i] */
+ for (i = MIN(deg_lambda,NROOTS-1) & ~1; i >= 0; i -=2) {
+ if(lambda[i+1] != A0)
+ den ^= ALPHA_TO[MODNN(lambda[i+1] + i * root[j])];
+ }
+#if DEBUG >= 1
+ if (den == 0) {
+ printf("\n ERROR: denominator = 0\n");
+ count = -1;
+ goto finish;
+ }
+#endif
+ /* Apply error to data */
+ if (num1 != 0 && loc[j] >= PAD) {
+ data[loc[j]-PAD] ^= ALPHA_TO[MODNN(INDEX_OF[num1] + INDEX_OF[num2] + NN - INDEX_OF[den])];
+ }
+ }
+ finish:
+ if(eras_pos != NULL){
+ for(i=0;i<count;i++)
+ eras_pos[i] = loc[i];
+ }
+ retval = count;
+}
diff --git a/fec/decode_rs_char.c b/fec/decode_rs_char.c
new file mode 100644
index 0000000..7105233
--- /dev/null
+++ b/fec/decode_rs_char.c
@@ -0,0 +1,22 @@
+/* General purpose Reed-Solomon decoder for 8-bit symbols or less
+ * Copyright 2003 Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+
+#ifdef DEBUG
+#include <stdio.h>
+#endif
+
+#include <string.h>
+
+#include "char.h"
+#include "rs-common.h"
+
+int decode_rs_char(void *p, data_t *data, int *eras_pos, int no_eras){
+ int retval;
+ struct rs *rs = (struct rs *)p;
+
+#include "decode_rs.h"
+
+ return retval;
+}
diff --git a/fec/encode_rs.h b/fec/encode_rs.h
new file mode 100644
index 0000000..2c157f9
--- /dev/null
+++ b/fec/encode_rs.h
@@ -0,0 +1,58 @@
+/* The guts of the Reed-Solomon encoder, meant to be #included
+ * into a function body with the following typedefs, macros and variables supplied
+ * according to the code parameters:
+
+ * data_t - a typedef for the data symbol
+ * data_t data[] - array of NN-NROOTS-PAD and type data_t to be encoded
+ * data_t parity[] - an array of NROOTS and type data_t to be written with parity symbols
+ * NROOTS - the number of roots in the RS code generator polynomial,
+ * which is the same as the number of parity symbols in a block.
+ Integer variable or literal.
+ *
+ * NN - the total number of symbols in a RS block. Integer variable or literal.
+ * PAD - the number of pad symbols in a block. Integer variable or literal.
+ * ALPHA_TO - The address of an array of NN elements to convert Galois field
+ * elements in index (log) form to polynomial form. Read only.
+ * INDEX_OF - The address of an array of NN elements to convert Galois field
+ * elements in polynomial form to index (log) form. Read only.
+ * MODNN - a function to reduce its argument modulo NN. May be inline or a macro.
+ * GENPOLY - an array of NROOTS+1 elements containing the generator polynomial in index form
+
+ * The memset() and memmove() functions are used. The appropriate header
+ * file declaring these functions (usually <string.h>) must be included by the calling
+ * program.
+
+ * Copyright 2004, Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+
+
+#undef A0
+#define A0 (NN) /* Special reserved value encoding zero in index form */
+
+{
+ int i, j;
+ data_t feedback;
+
+ memset(parity,0,NROOTS*sizeof(data_t));
+
+ for(i=0;i<NN-NROOTS-PAD;i++){
+ feedback = INDEX_OF[data[i] ^ parity[0]];
+ if(feedback != A0){ /* feedback term is non-zero */
+#ifdef UNNORMALIZED
+ /* This line is unnecessary when GENPOLY[NROOTS] is unity, as it must
+ * always be for the polynomials constructed by init_rs()
+ */
+ feedback = MODNN(NN - GENPOLY[NROOTS] + feedback);
+#endif
+ for(j=1;j<NROOTS;j++)
+ parity[j] ^= ALPHA_TO[MODNN(feedback + GENPOLY[NROOTS-j])];
+ }
+ /* Shift */
+ memmove(&parity[0],&parity[1],sizeof(data_t)*(NROOTS-1));
+ if(feedback != A0)
+ parity[NROOTS-1] = ALPHA_TO[MODNN(feedback + GENPOLY[0])];
+ else
+ parity[NROOTS-1] = 0;
+ }
+}
diff --git a/fec/encode_rs_char.c b/fec/encode_rs_char.c
new file mode 100644
index 0000000..a9bf2b8
--- /dev/null
+++ b/fec/encode_rs_char.c
@@ -0,0 +1,15 @@
+/* Reed-Solomon encoder
+ * Copyright 2002, Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+#include <string.h>
+
+#include "char.h"
+#include "rs-common.h"
+
+void encode_rs_char(void *p,data_t *data, data_t *parity){
+ struct rs *rs = (struct rs *)p;
+
+#include "encode_rs.h"
+
+}
diff --git a/fec/fec.h b/fec/fec.h
new file mode 100644
index 0000000..0d1bae1
--- /dev/null
+++ b/fec/fec.h
@@ -0,0 +1,30 @@
+/* Main header for reduced libfec.
+ *
+ * The FEC code in this folder is
+ * Copyright 2003 Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+
+#pragma once
+
+#include <stdlib.h>
+
+#include "char.h"
+#include "rs-common.h"
+
+/* Initialize a Reed-Solomon codec
+ * symsize = symbol size, bits
+ * gfpoly = Field generator polynomial coefficients
+ * fcr = first root of RS code generator polynomial, index form
+ * prim = primitive element to generate polynomial roots
+ * nroots = RS code generator polynomial degree (number of roots)
+ * pad = padding bytes at front of shortened block
+ */
+void *init_rs_char(int symsize,int gfpoly,int fcr,int prim,int nroots,int pad);
+
+int decode_rs_char(void *p, data_t *data, int *eras_pos, int no_eras);
+
+void encode_rs_char(void *p,data_t *data, data_t *parity);
+
+void free_rs_char(void *p);
+
diff --git a/fec/init_rs.h b/fec/init_rs.h
new file mode 100644
index 0000000..a5e8b4a
--- /dev/null
+++ b/fec/init_rs.h
@@ -0,0 +1,104 @@
+/* Common code for intializing a Reed-Solomon control block (char or int symbols)
+ * Copyright 2004 Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+
+{
+ int i, j, sr,root,iprim;
+
+ rs = NULL;
+ /* Check parameter ranges */
+ if(symsize < 0 || symsize > 8*sizeof(data_t)){
+ goto done;
+ }
+
+ if(fcr < 0 || fcr >= (1<<symsize))
+ goto done;
+ if(prim <= 0 || prim >= (1<<symsize))
+ goto done;
+ if(nroots < 0 || nroots >= (1<<symsize))
+ goto done; /* Can't have more roots than symbol values! */
+ if(pad < 0 || pad >= ((1<<symsize) -1 - nroots))
+ goto done; /* Too much padding */
+
+ rs = (struct rs *)calloc(1,sizeof(struct rs));
+ if(rs == NULL)
+ goto done;
+
+ rs->mm = symsize;
+ rs->nn = (1<<symsize)-1;
+ rs->pad = pad;
+
+ rs->alpha_to = (data_t *)malloc(sizeof(data_t)*(rs->nn+1));
+ if(rs->alpha_to == NULL){
+ free(rs);
+ rs = NULL;
+ goto done;
+ }
+ rs->index_of = (data_t *)malloc(sizeof(data_t)*(rs->nn+1));
+ if(rs->index_of == NULL){
+ free(rs->alpha_to);
+ free(rs);
+ rs = NULL;
+ goto done;
+ }
+
+ /* Generate Galois field lookup tables */
+ rs->index_of[0] = A0; /* log(zero) = -inf */
+ rs->alpha_to[A0] = 0; /* alpha**-inf = 0 */
+ sr = 1;
+ for(i=0;i<rs->nn;i++){
+ rs->index_of[sr] = i;
+ rs->alpha_to[i] = sr;
+ sr <<= 1;
+ if(sr & (1<<symsize))
+ sr ^= gfpoly;
+ sr &= rs->nn;
+ }
+ if(sr != 1){
+ /* field generator polynomial is not primitive! */
+ free(rs->alpha_to);
+ free(rs->index_of);
+ free(rs);
+ rs = NULL;
+ goto done;
+ }
+
+ /* Form RS code generator polynomial from its roots */
+ rs->genpoly = (data_t *)malloc(sizeof(data_t)*(nroots+1));
+ if(rs->genpoly == NULL){
+ free(rs->alpha_to);
+ free(rs->index_of);
+ free(rs);
+ rs = NULL;
+ goto done;
+ }
+ rs->fcr = fcr;
+ rs->prim = prim;
+ rs->nroots = nroots;
+
+ /* Find prim-th root of 1, used in decoding */
+ for(iprim=1;(iprim % prim) != 0;iprim += rs->nn)
+ ;
+ rs->iprim = iprim / prim;
+
+ rs->genpoly[0] = 1;
+ for (i = 0,root=fcr*prim; i < nroots; i++,root += prim) {
+ rs->genpoly[i+1] = 1;
+
+ /* Multiply rs->genpoly[] by @**(root + x) */
+ for (j = i; j > 0; j--){
+ if (rs->genpoly[j] != 0)
+ rs->genpoly[j] = rs->genpoly[j-1] ^ rs->alpha_to[modnn(rs,rs->index_of[rs->genpoly[j]] + root)];
+ else
+ rs->genpoly[j] = rs->genpoly[j-1];
+ }
+ /* rs->genpoly[0] can never be zero */
+ rs->genpoly[0] = rs->alpha_to[modnn(rs,rs->index_of[rs->genpoly[0]] + root)];
+ }
+ /* convert rs->genpoly[] to index form for quicker encoding */
+ for (i = 0; i <= nroots; i++)
+ rs->genpoly[i] = rs->index_of[rs->genpoly[i]];
+ done:;
+
+}
diff --git a/fec/init_rs_char.c b/fec/init_rs_char.c
new file mode 100644
index 0000000..a51099a
--- /dev/null
+++ b/fec/init_rs_char.c
@@ -0,0 +1,35 @@
+/* Initialize a RS codec
+ *
+ * Copyright 2002 Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+#include <stdlib.h>
+
+#include "char.h"
+#include "rs-common.h"
+
+void free_rs_char(void *p){
+ struct rs *rs = (struct rs *)p;
+
+ free(rs->alpha_to);
+ free(rs->index_of);
+ free(rs->genpoly);
+ free(rs);
+}
+
+/* Initialize a Reed-Solomon codec
+ * symsize = symbol size, bits
+ * gfpoly = Field generator polynomial coefficients
+ * fcr = first root of RS code generator polynomial, index form
+ * prim = primitive element to generate polynomial roots
+ * nroots = RS code generator polynomial degree (number of roots)
+ * pad = padding bytes at front of shortened block
+ */
+void *init_rs_char(int symsize,int gfpoly,int fcr,int prim,
+ int nroots,int pad){
+ struct rs *rs;
+
+#include "init_rs.h"
+
+ return rs;
+}
diff --git a/fec/rs-common.h b/fec/rs-common.h
new file mode 100644
index 0000000..e64eb39
--- /dev/null
+++ b/fec/rs-common.h
@@ -0,0 +1,26 @@
+/* Stuff common to all the general-purpose Reed-Solomon codecs
+ * Copyright 2004 Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+
+/* Reed-Solomon codec control block */
+struct rs {
+ int mm; /* Bits per symbol */
+ int nn; /* Symbols per block (= (1<<mm)-1) */
+ data_t *alpha_to; /* log lookup table */
+ data_t *index_of; /* Antilog lookup table */
+ data_t *genpoly; /* Generator polynomial */
+ int nroots; /* Number of generator roots = number of parity symbols */
+ int fcr; /* First consecutive root, index form */
+ int prim; /* Primitive element, index form */
+ int iprim; /* prim-th root of 1, index form */
+ int pad; /* Padding bytes in shortened block */
+};
+
+static inline int modnn(struct rs *rs,int x){
+ while (x >= rs->nn) {
+ x -= rs->nn;
+ x = (x >> rs->mm) + (x & rs->nn);
+ }
+ return x;
+}
diff --git a/test/main.cpp b/test/main.cpp
index babbba4..e2b76d7 100644
--- a/test/main.cpp
+++ b/test/main.cpp
@@ -27,7 +27,7 @@
int main(int argc, char **argv)
{
if (argc == 1) {
- fprintf(stderr, "Usage:\n %s <edi_file> [eti_file]", argv[0]);
+ fprintf(stderr, "Usage:\n %s <edi_file> [eti_file]\n", argv[0]);
return 1;
}