#pragma once

/**
 * zfec -- fast forward error correction library with Python interface
 * https://tahoe-lafs.org/trac/zfec/

 This package implements an "erasure code", or "forward error correction code".
 You may use this package under the GNU General Public License, version 2 or, at your option, any later version.
*/

#include <stddef.h>

typedef unsigned char gf;

typedef struct {
  unsigned long magic;
  unsigned short k, n;                     /* parameters of the code */
  gf* enc_matrix;
} fec_t;

#if defined(_MSC_VER)
// actually, some of the flavors (i.e. Enterprise) do support restrict
//#define restrict __restrict
#define restrict
#endif

/**
 * param k the number of blocks required to reconstruct
 * param m the total number of blocks created
 */
fec_t* fec_new(unsigned short k, unsigned short m);
void fec_free(fec_t* p);

/**
 * @param inpkts the "primary blocks" i.e. the chunks of the input data
 * @param fecs buffers into which the secondary blocks will be written
 * @param block_nums the numbers of the desired check blocks (the id >= k) which fec_encode() will produce and store into the buffers of the fecs parameter
 * @param num_block_nums the length of the block_nums array
 * @param sz size of a packet in bytes
 */
void fec_encode(const fec_t* code, const gf** src, gf** fecs, size_t sz);

/**
 * @param inpkts an array of packets (size k); If a primary block, i, is present then it must be at index i. Secondary blocks can appear anywhere.
 * @param outpkts an array of buffers into which the reconstructed output packets will be written (only packets which are not present in the inpkts input will be reconstructed and written to outpkts)
 * @param index an array of the blocknums of the packets in inpkts
 * @param sz size of a packet in bytes
 */
void fec_decode(const fec_t* code, const gf** inpkts, gf** outpkts, const unsigned*  index, size_t sz);

#if defined(_MSC_VER)
#define alloca _alloca
#else
#ifdef __GNUC__
#ifndef alloca
#define alloca(x) __builtin_alloca(x)
#endif
#else
#include <alloca.h>
#endif
#endif

/**
 * zfec -- fast forward error correction library with Python interface
 * 
 * Copyright (C) 2007-2008 Allmydata, Inc.
 * Author: Zooko Wilcox-O'Hearn
 * 
 * This file is part of zfec.
 * 
 * See README.rst for licensing information.
 */

/*
 * Much of this work is derived from the "fec" software by Luigi Rizzo, et 
 * al., the copyright notice and licence terms of which are included below 
 * for reference.
 * 
 * fec.h -- forward error correction based on Vandermonde matrices
 * 980614
 * (C) 1997-98 Luigi Rizzo (luigi@iet.unipi.it)
 *
 * Portions derived from code by Phil Karn (karn@ka9q.ampr.org),
 * Robert Morelos-Zaragoza (robert@spectra.eng.hawaii.edu) and Hari
 * Thirumoorthy (harit@spectra.eng.hawaii.edu), Aug 1995
 *
 * Modifications by Dan Rubenstein (see Modifications.txt for 
 * their description.
 * Modifications (C) 1998 Dan Rubenstein (drubenst@cs.umass.edu)
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:

 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 */

