#include "amanda.h"
#include <regex.h>
#include "utils.h"
#include "regerror.ih"

/*
 = #define	REG_OKAY	 0
 = #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_OKAY,	"REG_OKAY",	"no errors detected"},
	{ 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"},
	{ -1,		"",		"*** 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(
    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, SIZEOF(convbuf));
	else {
		for (r = rerrs; r->code >= 0; r++)
			if (r->code == target)
				break;

		if (errcode&REG_ITOA) {
			if (r->code >= 0) {
				strncpy(convbuf, r->name, SIZEOF(convbuf)-1);
				convbuf[SIZEOF(convbuf)-1] = '\0';
			} else {
				snprintf(convbuf, SIZEOF(convbuf),
					    "REG_0x%x", (unsigned)target);
			}
			assert(strlen(convbuf) < SIZEOF(convbuf));
			s = convbuf;
		} else
			s = r->explain;
	}

	len = strlen(s) + 1;
	if (errbuf_size > 0) {
		(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, size_t buflen);
 */
static char *
regatoi(
    const regex_t *	preg,
    char *		localbuf,
    size_t		buflen)
{
	register struct rerr *r;

	for (r = rerrs; r->code >= 0; r++) {
		/*@ignore@*/
		if (strcmp(r->name, preg->re_endp) == 0)
			break;
		/*@end@*/
	}
	if (r->code < 0)
		return("0");

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