/*
Copyright 1992, 1993, 1994, 1997 Henry Spencer.  All rights reserved.
This software is not subject to any license of the American Telephone
and Telegraph Company or of the Regents of the University of California.

Permission is granted to anyone to use this software for any purpose on
any computer system, and to alter it and redistribute it, subject
to the following restrictions:

1. The author is not responsible for the consequences of use of this
   software, no matter how awful, even if they arise from flaws in it.

2. The origin of this software must not be misrepresented, either by
   explicit claim or by omission.  Since few users ever read sources,
   credits must appear in the documentation.

3. Altered versions must be plainly marked as such, and must not be
   misrepresented as being the original software.  Since few users
   ever read sources, credits must appear in the documentation.

4. This notice may not be removed or altered.
*/
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include <stdlib.h>
#include <regex.h>

#include "utils.h"
#include "regerror.ih"

/*
 = #define	REG_NOMATCH	 1
 = #define	REG_BADPAT	 2
 = #define	REG_ECOLLATE	 3
 = #define	REG_ECTYPE	 4
 = #define	REG_EESCAPE	 5
 = #define	REG_ESUBREG	 6
 = #define	REG_EBRACK	 7
 = #define	REG_EPAREN	 8
 = #define	REG_EBRACE	 9
 = #define	REG_BADBR	10
 = #define	REG_ERANGE	11
 = #define	REG_ESPACE	12
 = #define	REG_BADRPT	13
 = #define	REG_EMPTY	14
 = #define	REG_ASSERT	15
 = #define	REG_INVARG	16
 = #define	REG_ATOI	255	// convert name to number (!)
 = #define	REG_ITOA	0400	// convert number to name (!)
 */
static struct rerr {
	int code;
	char *name;
	char *explain;
} rerrs[] = {
	{ REG_NOMATCH,	"REG_NOMATCH",	"regexec() failed to match" },
	{ REG_BADPAT,	"REG_BADPAT",	"invalid regular expression" },
	{ REG_ECOLLATE,	"REG_ECOLLATE",	"invalid collating element" },
	{ REG_ECTYPE,	"REG_ECTYPE",	"invalid character class" },
	{ REG_EESCAPE,	"REG_EESCAPE",	"trailing backslash (\\)" },
	{ REG_ESUBREG,	"REG_ESUBREG",	"invalid backreference number" },
	{ REG_EBRACK,	"REG_EBRACK",	"brackets ([ ]) not balanced" },
	{ REG_EPAREN,	"REG_EPAREN",	"parentheses not balanced" },
	{ REG_EBRACE,	"REG_EBRACE",	"braces not balanced" },
	{ REG_BADBR,	"REG_BADBR",	"invalid repetition count(s)" },
	{ REG_ERANGE,	"REG_ERANGE",	"invalid character range" },
	{ REG_ESPACE,	"REG_ESPACE",	"out of memory" },
	{ REG_BADRPT,	"REG_BADRPT",	"repetition-operator operand invalid" },
	{ REG_EMPTY,	"REG_EMPTY",	"empty (sub)expression" },
	{ REG_ASSERT,	"REG_ASSERT",	"\"can't happen\" -- you found a bug" },
	{ REG_INVARG,	"REG_INVARG",	"invalid argument to regex routine" },
	{ 0,		"",		"*** unknown regexp error code ***" }
};

/*
 - regerror - the interface to error numbers
 = extern size_t regerror(int, const regex_t *, char *, size_t);
 */
/* ARGSUSED */
size_t
regerror(errcode, preg, errbuf, errbuf_size)
int errcode;
const regex_t *preg;
char *errbuf;
size_t errbuf_size;
{
	register struct rerr *r;
	register size_t len;
	register int target = errcode &~ REG_ITOA;
	register char *s;
	char convbuf[50];

	if (errcode == REG_ATOI)
		s = regatoi(preg, convbuf);
	else {
		for (r = rerrs; r->code != 0; r++)
			if (r->code == target)
				break;
	
		if (errcode&REG_ITOA) {
			if (r->code != 0)
				(void) strcpy(convbuf, r->name);
			else
				sprintf(convbuf, "REG_0x%x", target);
			assert(strlen(convbuf) < sizeof(convbuf));
			s = convbuf;
		} else
			s = r->explain;
	}

	len = strlen(s) + 1;
	if (errbuf_size > 0) {
		if (errbuf_size > len)
			(void) strcpy(errbuf, s);
		else {
			(void) strncpy(errbuf, s, errbuf_size-1);
			errbuf[errbuf_size-1] = '\0';
		}
	}

	return(len);
}

/*
 - regatoi - internal routine to implement REG_ATOI
 == static char *regatoi(const regex_t *preg, char *localbuf);
 */
static char *
regatoi(preg, localbuf)
const regex_t *preg;
char *localbuf;
{
	register struct rerr *r;

	for (r = rerrs; r->code != 0; r++)
		if (strcmp(r->name, preg->re_endp) == 0)
			break;
	if (r->code == 0)
		return("0");

	sprintf(localbuf, "%d", r->code);
	return(localbuf);
}

__SRCVERSION("regerror.c $Rev: 153052 $");
