Copyright (C) 1992, 1997-2002, 2004-2020 Free Software Foundation, Inc. Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. Mike Haertel wrote the main program and the dfa and kwset matchers. Isamu Hasegawa wrote the POSIX regular expression matcher, which is part of the GNU C Library and is distributed as part of GNU grep for use on non-GNU systems. Ulrich Drepper, Paul Eggert, Paolo Bonzini, Stanislav Brabec, Assaf Gordon, Jakub Jelinek, Jim Meyering, Arnold Robbins, Andreas Schwab and Florian Weimer also contributed to this matcher. Arthur David Olson contributed the heuristics for finding fixed substrings at the end of dfa.c. Henry Spencer wrote the original test suite from which grep's was derived. Scott Anderson invented the Khadafy test. David MacKenzie wrote the automatic configuration software used to produce the configure script. Authors of the replacements for standard library routines are identified in the corresponding source files. The idea of using Boyer-Moore type algorithms to quickly filter out non-matching text before calling the regexp matcher was originally due to James Woods. He also contributed some code to early versions of GNU grep. Mike Haertel would like to thank Andrew Hume for many fascinating discussions of string searching issues over the years. Hume and Sunday's excellent paper on fast string searching describes some of the history of the subject, as well as providing exhaustive performance analysis of various implementation alternatives. The inner loop of GNU grep is similar to Hume & Sunday's recommended "Tuned Boyer Moore" inner loop. See: Hume A, Sunday D. Fast string searching. Software Pract Exper. 1991;21(11):1221-48. https://doi.org/10.1002/spe.4380211105 Arnold Robbins contributed to improve dfa.[ch]. In fact it came straight from gawk-3.0.3 with small editing and fixes. Many folks contributed. See THANKS; if I omitted someone please send me email. Alain Magloire maintained GNU grep until version 2.5e. Bernhard "Bero" Rosenkränzer <bero@arklinux.org> maintained GNU grep until version 2.5.1, ie. from Sep 2001 till 2003. Stepan Kasal <kasal@ucw.cz> maintained GNU grep since Feb 2004. Tony Abou-Assaleh <taa@acm.org> maintains GNU grep since Oct 2007. Jim Meyering <jim@meyering.net> and Paolo Bonzini <bonzini@gnu.org> began maintaining GNU grep in Nov 2009. Paolo bowed out in 2012. ;; Local Variables: ;; coding: utf-8 ;; End: