text: /* $XFree86: xc/extras/regex/regerror.c,v 1.2 2005/06/07 08:02:14 dawes Exp $ */
  
  #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_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(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);
  }
  