1# infectious 2 3[![GoDoc](https://godoc.org/github.com/vivint/infectious?status.png)](https://godoc.org/github.com/vivint/infectious) 4 5Infectious implements 6[Reed-Solomon forward error correction](https://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_correction). 7It uses the 8[Berlekamp-Welch error correction algorithm](https://en.wikipedia.org/wiki/Berlekamp%E2%80%93Welch_algorithm) 9to achieve the ability to actually correct errors. 10 11[We wrote a blog post about how this library works!](https://innovation.vivint.com/introduction-to-reed-solomon-bc264d0794f8) 12 13### Example 14 15```golang 16const ( 17 required = 8 18 total = 14 19) 20 21// Create a *FEC, which will require required pieces for reconstruction at 22// minimum, and generate total total pieces. 23f, err := infectious.NewFEC(required, total) 24if err != nil { 25 panic(err) 26} 27 28// Prepare to receive the shares of encoded data. 29shares := make([]infectious.Share, total) 30output := func(s infectious.Share) { 31 // the memory in s gets reused, so we need to make a deep copy 32 shares[s.Number] = s.DeepCopy() 33} 34 35// the data to encode must be padded to a multiple of required, hence the 36// underscores. 37err = f.Encode([]byte("hello, world! __"), output) 38if err != nil { 39 panic(err) 40} 41 42// we now have total shares. 43for _, share := range shares { 44 fmt.Printf("%d: %#v\n", share.Number, string(share.Data)) 45} 46 47// Let's reconstitute with two pieces missing and one piece corrupted. 48shares = shares[2:] // drop the first two pieces 49shares[2].Data[1] = '!' // mutate some data 50 51result, err := f.Decode(nil, shares) 52if err != nil { 53 panic(err) 54} 55 56// we have the original data! 57fmt.Printf("got: %#v\n", string(result)) 58``` 59 60**Caution:** this package API leans toward providing the user more power and 61performance at the expense of having some really sharp edges! Read the 62documentation about memory lifecycles carefully! 63 64Please see the docs at http://godoc.org/github.com/vivint/infectious 65 66### Thanks 67 68We're forever indebted to the giants on whose shoulders we stand. The LICENSE 69has our full copyright history, but an extra special thanks to Klaus Post for 70much of the initial Go code. See his post for more: 71http://blog.klauspost.com/blazingly-fast-reed-solomon-coding/ 72 73### LICENSE 74 75 * Copyright (C) 2016-2017 Vivint, Inc. 76 * Copyright (c) 2015 Klaus Post 77 * Copyright (c) 2015 Backblaze 78 * Copyright (C) 2011 Billy Brumley (billy.brumley@aalto.fi) 79 * Copyright (C) 2009-2010 Jack Lloyd (lloyd@randombit.net) 80 * Copyright (C) 1996-1998 Luigi Rizzo (luigi@iet.unipi.it) 81 82Portions derived from code by Phil Karn (karn@ka9q.ampr.org), 83Robert Morelos-Zaragoza (robert@spectra.eng.hawaii.edu) and Hari 84Thirumoorthy (harit@spectra.eng.hawaii.edu), Aug 1995 85 86**Portions of this project (labeled in each file) are licensed under this 87license:** 88 89Redistribution and use in source and binary forms, with or without 90modification, are permitted provided that the following conditions are 91met: 92 931. Redistributions of source code must retain the above copyright 94 notice, this list of conditions and the following disclaimer. 95 962. Redistributions in binary form must reproduce the above copyright 97 notice, this list of conditions and the following disclaimer in the 98 documentation and/or other materials provided with the 99 distribution. 100 101THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 102IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 103WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 104DISCLAIMED. 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