awk.shar

c programming pearls answer

# To unbundle, sh this file
echo README 1>&2
sed 's/.//' >README <<'//GO.SYSIN DD README'
-/****************************************************************
-Copyright (C) Lucent Technologies 1997
-All Rights Reserved
-
-Permission to use, copy, modify, and distribute this software and
-its documentation for any purpose and without fee is hereby
-granted, provided that the above copyright notice appear in all
-copies and that both that the copyright notice and this
-permission notice and warranty disclaimer appear in supporting
-documentation, and that the name Lucent Technologies or any of
-its entities not be used in advertising or publicity pertaining
-to distribution of the software without specific, written prior
-permission.
-
-LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
-INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
-IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
-SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
-IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
-ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
-THIS SOFTWARE.
-****************************************************************/
-
-This is the version of awk described in "The AWK Programming Language",
-by Al Aho, Brian Kernighan, and Peter Weinberger
-(Addison-Wesley, 1988, ISBN 0-201-07981-X).
-
-Changes, mostly bug fixes and occasional enhancements, are listed
-in FIXES.  If you distribute this code further, please please please
-distribute FIXES with it.  If you find errors, please report them
-to [e-mail].  Thanks.
-
-The program itself is created by
-	make
-which should produce a sequence of messages roughly like this:
-
-	yacc -d awkgram.y
-
-conflicts: 43 shift/reduce, 85 reduce/reduce
-	mv y.tab.c ytab.c
-	mv y.tab.h ytab.h
-	cc -c ytab.c
-	cc -c b.c
-	cc -c main.c
-	cc -c parse.c
-	cc maketab.c -o maketab
-	./maketab >proctab.c
-	cc -c proctab.c
-	cc -c tran.c
-	cc -c lib.c
-	cc -c run.c
-	cc -c lex.c
-	cc ytab.o b.o main.o parse.o proctab.o tran.o lib.o run.o lex.o -lm
-
-This produces an executable a.out; you will eventually want to
-move this to some place like /usr/bin/awk.
-
-If your system does not have yacc or bison (the GNU
-equivalent), you must compile the pieces manually.  We have
-included yacc output in ytab.c and ytab.h, and backup copies in
-case you overwrite them.  We have also included a copy of
-proctab.c so you do not need to run maketab.
-
-NOTE: This version uses ANSI C, as you should also.  We have
-compiled this without any changes using gcc -Wall and/or local C
-compilers on a variety of systems, but new systems or compilers
-may raise some new complaint; reports of difficulties are
-welcome.
-
-This also compiles with Visual C++ on all flavors of Windows,
-*if* you provide versions of popen and pclose.  The file
-missing95.c contains versions that can be used to get started
-with, though the underlying support has mysterious properties,
-the symptom of which can be truncated pipe output.  Beware.  The
-file makefile.win gives hints on how to proceed; if you run
-vcvars32.bat, it will set up necessary paths and parameters so
-you can subsequently run nmake -f makefile.win.  Beware also that
-when running on Windows under command.com, various quoting
-conventions are different from Unix systems: single quotes won't
-work around arguments, and various characters like % are
-interpreted within double quotes.
-
-This compiles without change on Macintosh OS X using gcc and
-the standard developer tools.
-
-This is also said to compile on Macintosh OS 9 systems, using the
-file "buildmac" provided by Dan Allen ([e-mail]),
-to whom many thanks.
-
-The version of malloc that comes with some systems is sometimes
-astonishly slow.  If awk seems slow, you might try fixing that.
-More generally, turning on optimization can significantly improve
-awk's speed, perhaps by 1/3 for highest levels.
//GO.SYSIN DD README
echo FIXES 1>&2
sed 's/.//' >FIXES <<'//GO.SYSIN DD FIXES'
-/****************************************************************
-Copyright (C) Lucent Technologies 1997
-All Rights Reserved
-
-Permission to use, copy, modify, and distribute this software and
-its documentation for any purpose and without fee is hereby
-granted, provided that the above copyright notice appear in all
-copies and that both that the copyright notice and this
-permission notice and warranty disclaimer appear in supporting
-documentation, and that the name Lucent Technologies or any of
-its entities not be used in advertising or publicity pertaining
-to distribution of the software without specific, written prior
-permission.
-
-LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
-INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
-IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
-SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
-IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
-ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
-THIS SOFTWARE.
-****************************************************************/
-
-This file lists all bug fixes, changes, etc., made since the AWK book
-was sent to the printers in August, 1987.
-
-Apr 24, 2005:
-	modified lib.c so that values of $0 et al are preserved in the END
-	block, apparently as required by posix.  thanks to havard eidnes
-	for the report and code.
-
-Jan 14, 2005:
-	fixed infinite loop in parsing, originally found by brian tsang.
-	thanks to arnold robbins for a suggestion that started me
-	rethinking it.
-
-Dec 31, 2004:
-	prevent overflow of -f array in main, head off potential error in 
-	call of SYNTAX(), test malloc return in lib.c, all with thanks to 
-	todd miller.
-
-Dec 22, 2004:
-	cranked up size of NCHARS; coverity thinks it can be overrun with
-	smaller size, and i think that's right.  added some assertions to b.c
-	to catch places where it might overrun.  the RE code is still fragile.
-
-Dec 5, 2004:
-	fixed a couple of overflow problems with ridiculous field numbers:
-	e.g., print $(2^32-1).  thanks to ruslan ermilov, giorgos keramidas
-	and david o'brien at freebsd.org for patches.  this really should
-	be re-done from scratch.
-
-Nov 21, 2004:
-	fixed another 25-year-old RE bug, in split.  it's another failure
-	to (re-)initialize.  thanks to steve fisher for spotting this and
-	providing a good test case.
-
-Nov 22, 2003:
-	fixed a bug in regular expressions that dates (so help me) from 1977;
-	it's been there from the beginning.  an anchored longest match that
-	was longer than the number of states triggered a failure to initialize
-	the machine properly.  many thanks to moinak ghosh for not only finding
-	this one but for providing a fix, in some of the most mysterious
-	code known to man.
-
-	fixed a storage leak in call() that appears to have been there since
-	1983 or so -- a function without an explicit return that assigns a 
-	string to a parameter leaked a Cell.  thanks to moinak ghosh for 
-	spotting this very subtle one.
-
-Jul 31, 2003:
-	fixed, thanks to andrey chernov and ruslan ermilov, a bug in lex.c
-	that mis-handled the character 255 in input.  (it was being compared
-	to EOF with a signed comparison.)
-
-Jul 29, 2003:
-	fixed (i think) the long-standing botch that included the beginning of
-	line state ^ for RE's in the set of valid characters; this led to a
-	variety of odd problems, including failure to properly match certain
-	regular expressions in non-US locales.  thanks to ruslan for keeping
-	at this one.
-
-Jul 28, 2003:
-	n-th try at getting internationalization right, with thanks to volker
-	kiefel, arnold robbins and ruslan ermilov for advice, though they
-	should not be blamed for the outcome.  according to posix, "."  is the
-	radix character in programs and command line arguments regardless of
-	the locale; otherwise, the locale should prevail for input and output
-	of numbers.  so it's intended to work that way.
-	
-	i have rescinded the attempt to use strcoll in expanding shorthands in
-	regular expressions (cclenter).  its properties are much too
-	surprising; for example [a-c] matches aAbBc in locale en_US but abBcC
-	in locale fr_CA.  i can see how this might arise by implementation
-	but i cannot explain it to a human user.  (this behavior can be seen
-	in gawk as well; we're leaning on the same library.)
-
-	the issue appears to be that strcoll is meant for sorting, where
-	merging upper and lower case may make sense (though note that unix
-	sort does not do this by default either).  it is not appropriate
-	for regular expressions, where the goal is to match specific
-	patterns of characters.  in any case, the notations [:lower:], etc.,
-	are available in awk, and they are more likely to work correctly in
-	most locales.
-
-	a moratorium is hereby declared on internationalization changes.
-	i apologize to friends and colleagues in other parts of the world.
-	i would truly like to get this "right", but i don't know what
-	that is, and i do not want to keep making changes until it's clear.
-
-Jul 4, 2003:
-	fixed bug that permitted non-terminated RE, as in "awk /x".
-
-Jun 1, 2003:
-	subtle change to split: if source is empty, number of elems
-	is always 0 and the array is not set.
-
-Mar 21, 2003:
-	added some parens to isblank, in another attempt to make things
-	internationally portable.
-
-Mar 14, 2003:
-	the internationalization changes, somewhat modified, are now
-	reinstated.  in theory awk will now do character comparisons
-	and case conversions in national language, but "." will always
-	be the decimal point separator on input and output regardless
-	of national language.  isblank(){} has an #ifndef.
-
-	this no longer compiles on windows: LC_MESSAGES isn't defined
-	in vc6++.
-
-	fixed subtle behavior in field and record splitting: if FS is
-	a single character and RS is not empty, \n is NOT a separator.
-	this tortuous reading is found in the awk book; behavior now
-	matches gawk and mawk.
-
-Dec 13, 2002:
-	for the moment, the internationalization changes of nov 29 are
-	rolled back -- programs like x = 1.2 don't work in some locales,
-	because the parser is expecting x = 1,2.  until i understand this
-	better, this will have to wait.
-
-Nov 29, 2002:
-	modified b.c (with tiny changes in main and run) to support
-	locales, using strcoll and iswhatever tests for posix character
-	classes.  thanks to ruslan ermilov ([e-mail]) for code.
-	the function isblank doesn't seem to have propagated to any
-	header file near me, so it's there explicitly.  not properly
-	tested on non-ascii character sets by me.
-
-Jun 28, 2002:
-	modified run/format() and tran/getsval() to do a slightly better
-	job on using OFMT for output from print and CONVFMT for other
-	number->string conversions, as promised by posix and done by 
-	gawk and mawk.  there are still places where it doesn't work
-	right if CONVFMT is changed; by then the STR attribute of the
-	variable has been irrevocably set.  thanks to arnold robbins for
-	code and examples.
-
-	fixed subtle bug in format that could get core dump.  thanks to
-	Jaromir Dolecek <[e-mail]> for finding and fixing.
-	minor cleanup in run.c / format() at the same time.
-
-	added some tests for null pointers to debugging printf's, which
-	were never intended for external consumption.  thanks to dave
-	kerns ([e-mail]) for pointing this out.
-
-	GNU compatibility: an empty regexp matches anything (thanks to
-	dag-erling smorgrav, [e-mail]).  subject to reversion if
-	this does more harm than good.
-
-	pervasive small changes to make things more const-correct, as
-	reported by gcc's -Wwrite-strings.  as it says in the gcc manual,
-	this may be more nuisance than useful.  provoked by a suggestion
-	and code from arnaud desitter, [e-mail]
-
-	minor documentation changes to note that this now compiles out
-	of the box on Mac OS X.
-
-Feb 10, 2002:
-	changed types in posix chars structure to quiet solaris cc.
-
-Jan 1, 2002:
-	fflush() or fflush("") flushes all files and pipes.
-
-	length(arrayname) returns number of elements; thanks to 
-	arnold robbins for suggestion.
-
-	added a makefile.win to make it easier to build on windows.
-	based on dan allen's buildwin.bat.
-
-Nov 16, 2001:
-	added support for posix character class names like [:digit:],
-	which are not exactly shorter than [0-9] and perhaps no more
-	portable.  thanks to dag-erling smorgrav for code.
-
-Feb 16, 2001:
-	removed -m option; no longer needed, and it was actually
-	broken (noted thanks to volker kiefel).
-
-Feb 10, 2001:
-	fixed an appalling bug in gettok: any sequence of digits, +,-, E, e,
-	and period was accepted as a valid number if it started with a period.
-	this would never have happened with the lex version.
-
-	other 1-character botches, now fixed, include a bare $ and a
-	bare " at the end of the input.
-
-Feb 7, 2001:
-	more (const char *) casts in b.c and tran.c to silence warnings.
-
-Nov 15, 2000:
-	fixed a bug introduced in august 1997 that caused expressions
-	like $f[1] to be syntax errors.  thanks to arnold robbins for
-	noticing this and providing a fix.
-
-Oct 30, 2000:
-	fixed some nextfile bugs: not handling all cases.  thanks to
-	arnold robbins for pointing this out.  new regressions added.
-
-	close() is now a function.  it returns whatever the library
-	fclose returns, and -1 for closing a file or pipe that wasn't
-	opened.
-
-Sep 24, 2000:
-	permit \n explicitly in character classes; won't work right
-	if comes in as "[\n]" but ok as /[\n]/, because of multiple
-	processing of \'s.  thanks to arnold robbins.
-
-July 5, 2000:
-	minor fiddles in tran.c to keep compilers happy about uschar.
-	thanks to norman wilson.
-
-May 25, 2000:
-	yet another attempt at making 8-bit input work, with another
-	band-aid in b.c (member()), and some (uschar) casts to head 
-	off potential errors in subscripts (like isdigit).  also
-	changed HAT to NCHARS-2.  thanks again to santiago vila.
-
-	changed maketab.c to ignore apparently out of range definitions
-	instead of halting; new freeBSD generates one.  thanks to
-	jon snader <[e-mail]> for pointing out the problem.
-
-May 2, 2000:
-	fixed an 8-bit problem in b.c by making several char*'s into
-	unsigned char*'s.  not clear i have them all yet.  thanks to
-	Santiago Vila <[e-mail]> for the bug report.
-
-Apr 21, 2000:
-	finally found and fixed a memory leak in function call; it's
-	been there since functions were added ~1983.  thanks to
-	jon bentley for the test case that found it.
-
-	added test in envinit to catch environment "variables" with
-	names beginning with '='; thanks to Berend Hasselman.
-
-Jul 28, 1999:
-	added test in defn() to catch function foo(foo), which
-	otherwise recurses until core dump.  thanks to arnold
-	robbins for noticing this.
-
-Jun 20, 1999:
-	added *bp in gettok in lex.c; appears possible to exit function
-	without terminating the string.  thanks to russ cox.
-