1 1.2 perry # $NetBSD: README,v 1.2 1998/01/09 04:12:00 perry Exp $ 2 1.2 perry 3 1.1 cgd This is a nearly-public-domain reimplementation of the V8 regexp(3) package. 4 1.1 cgd It gives C programs the ability to use egrep-style regular expressions, and 5 1.1 cgd does it in a much cleaner fashion than the analogous routines in SysV. 6 1.1 cgd 7 1.1 cgd Copyright (c) 1986 by University of Toronto. 8 1.1 cgd Written by Henry Spencer. Not derived from licensed software. 9 1.1 cgd 10 1.1 cgd Permission is granted to anyone to use this software for any 11 1.1 cgd purpose on any computer system, and to redistribute it freely, 12 1.1 cgd subject to the following restrictions: 13 1.1 cgd 14 1.1 cgd 1. The author is not responsible for the consequences of use of 15 1.1 cgd this software, no matter how awful, even if they arise 16 1.1 cgd from defects in it. 17 1.1 cgd 18 1.1 cgd 2. The origin of this software must not be misrepresented, either 19 1.1 cgd by explicit claim or by omission. 20 1.1 cgd 21 1.1 cgd 3. Altered versions must be plainly marked as such, and must not 22 1.1 cgd be misrepresented as being the original software. 23 1.1 cgd 24 1.1 cgd Barring a couple of small items in the BUGS list, this implementation is 25 1.1 cgd believed 100% compatible with V8. It should even be binary-compatible, 26 1.1 cgd sort of, since the only fields in a "struct regexp" that other people have 27 1.1 cgd any business touching are declared in exactly the same way at the same 28 1.1 cgd location in the struct (the beginning). 29 1.1 cgd 30 1.1 cgd This implementation is *NOT* AT&T/Bell code, and is not derived from licensed 31 1.1 cgd software. Even though U of T is a V8 licensee. This software is based on 32 1.1 cgd a V8 manual page sent to me by Dennis Ritchie (the manual page enclosed 33 1.1 cgd here is a complete rewrite and hence is not covered by AT&T copyright). 34 1.1 cgd The software was nearly complete at the time of arrival of our V8 tape. 35 1.1 cgd I haven't even looked at V8 yet, although a friend elsewhere at U of T has 36 1.1 cgd been kind enough to run a few test programs using the V8 regexp(3) to resolve 37 1.1 cgd a few fine points. I admit to some familiarity with regular-expression 38 1.1 cgd implementations of the past, but the only one that this code traces any 39 1.1 cgd ancestry to is the one published in Kernighan & Plauger (from which this 40 1.1 cgd one draws ideas but not code). 41 1.1 cgd 42 1.1 cgd Simplistically: put this stuff into a source directory, copy regexp.h into 43 1.1 cgd /usr/include, inspect Makefile for compilation options that need changing 44 1.1 cgd to suit your local environment, and then do "make r". This compiles the 45 1.1 cgd regexp(3) functions, compiles a test program, and runs a large set of 46 1.1 cgd regression tests. If there are no complaints, then put regexp.o, regsub.o, 47 1.1 cgd and regerror.o into your C library, and regexp.3 into your manual-pages 48 1.1 cgd directory. 49 1.1 cgd 50 1.1 cgd Note that if you don't put regexp.h into /usr/include *before* compiling, 51 1.1 cgd you'll have to add "-I." to CFLAGS before compiling. 52 1.1 cgd 53 1.1 cgd The files are: 54 1.1 cgd 55 1.1 cgd Makefile instructions to make everything 56 1.1 cgd regexp.3 manual page 57 1.1 cgd regexp.h header file, for /usr/include 58 1.1 cgd regexp.c source for regcomp() and regexec() 59 1.1 cgd regsub.c source for regsub() 60 1.1 cgd regerror.c source for default regerror() 61 1.1 cgd regmagic.h internal header file 62 1.1 cgd try.c source for test program 63 1.1 cgd timer.c source for timing program 64 1.1 cgd tests test list for try and timer 65 1.1 cgd 66 1.1 cgd This implementation uses nondeterministic automata rather than the 67 1.1 cgd deterministic ones found in some other implementations, which makes it 68 1.1 cgd simpler, smaller, and faster at compiling regular expressions, but slower 69 1.1 cgd at executing them. In theory, anyway. This implementation does employ 70 1.1 cgd some special-case optimizations to make the simpler cases (which do make 71 1.1 cgd up the bulk of regular expressions actually used) run quickly. In general, 72 1.1 cgd if you want blazing speed you're in the wrong place. Replacing the insides 73 1.1 cgd of egrep with this stuff is probably a mistake; if you want your own egrep 74 1.1 cgd you're going to have to do a lot more work. But if you want to use regular 75 1.1 cgd expressions a little bit in something else, you're in luck. Note that many 76 1.1 cgd existing text editors use nondeterministic regular-expression implementations, 77 1.1 cgd so you're in good company. 78 1.1 cgd 79 1.1 cgd This stuff should be pretty portable, given appropriate option settings. 80 1.1 cgd If your chars have less than 8 bits, you're going to have to change the 81 1.1 cgd internal representation of the automaton, although knowledge of the details 82 1.1 cgd of this is fairly localized. There are no "reserved" char values except for 83 1.1 cgd NUL, and no special significance is attached to the top bit of chars. 84 1.1 cgd The string(3) functions are used a fair bit, on the grounds that they are 85 1.1 cgd probably faster than coding the operations in line. Some attempts at code 86 1.1 cgd tuning have been made, but this is invariably a bit machine-specific. 87
Indexes created Sun Sep 21 20:09:37 GMT 2025