/*
 * THIS CODE IS SPECIFICALLY EXEMPTED FROM THE NCURSES PACKAGE COPYRIGHT.
 * You may freely copy it for use as a template for your own field types.
 * If you develop a field type that might be of general use, please send
 * it back to the ncurses maintainers for inclusion in the next version.
 */
/***************************************************************************
*                                                                          *
*  Author : Juergen Pfeifer                                                *
*                                                                          *
***************************************************************************/

#include "form.priv.h"

MODULE_ID("$Id: fty_regex.c,v 1.18 2004/05/29 19:19:09 tom Exp $")

#if HAVE_REGEX_H_FUNCS		/* We prefer POSIX regex */
#include <regex.h>

typedef struct
  {
    regex_t *pRegExp;
    unsigned long *refCount;
  }
RegExp_Arg;

#elif HAVE_REGEXP_H_FUNCS | HAVE_REGEXPR_H_FUNCS
#undef RETURN
static int reg_errno;

static char *
RegEx_Init(char *instring)
{
  reg_errno = 0;
  return instring;
}

static char *
RegEx_Error(int code)
{
  reg_errno = code;
  return 0;
}

#define INIT 		register char *sp = RegEx_Init(instring);
#define GETC()		(*sp++)
#define PEEKC()		(*sp)
#define UNGETC(c)	(--sp)
#define RETURN(c)	return(c)
#define ERROR(c)	return RegEx_Error(c)

#if HAVE_REGEXP_H_FUNCS
#include <regexp.h>
#else
#include <regexpr.h>
#endif

typedef struct
{
  char *compiled_expression;
  unsigned long *refCount;
}
RegExp_Arg;

/* Maximum Length we allow for a compiled regular expression */
#define MAX_RX_LEN   (2048)
#define RX_INCREMENT (256)

#endif

/*---------------------------------------------------------------------------
|   Facility      :  libnform
|   Function      :  static void *Make_RegularExpression_Type(va_list * ap)
|
|   Description   :  Allocate structure for regex type argument.
|
|   Return Values :  Pointer to argument structure or NULL on error
+--------------------------------------------------------------------------*/
static void *
Make_RegularExpression_Type(va_list *ap)
{
#if HAVE_REGEX_H_FUNCS
  char *rx = va_arg(*ap, char *);
  RegExp_Arg *preg;

  preg = (RegExp_Arg *)malloc(sizeof(RegExp_Arg));

  if (preg)
    {
      if (((preg->pRegExp = (regex_t *) malloc(sizeof(regex_t))) != 0)
	  && !regcomp(preg->pRegExp, rx,
		      (REG_EXTENDED | REG_NOSUB | REG_NEWLINE)))
	{
	  preg->refCount = (unsigned long *)malloc(sizeof(unsigned long));

	  *(preg->refCount) = 1;
	}
      else
	{
	  if (preg->pRegExp)
	    free(preg->pRegExp);
	  free(preg);
	  preg = (RegExp_Arg *)0;
	}
    }
  return ((void *)preg);
#elif HAVE_REGEXP_H_FUNCS | HAVE_REGEXPR_H_FUNCS
  char *rx = va_arg(*ap, char *);
  RegExp_Arg *pArg;

  pArg = (RegExp_Arg *)malloc(sizeof(RegExp_Arg));

  if (pArg)
    {
      int blen = RX_INCREMENT;

      pArg->compiled_expression = NULL;
      pArg->refCount = (unsigned long *)malloc(sizeof(unsigned long));

      *(pArg->refCount) = 1;

      do
	{
	  char *buf = (char *)malloc(blen);

	  if (buf)
	    {
#if HAVE_REGEXP_H_FUNCS
	      char *last_pos = compile(rx, buf, &buf[blen], '\0');

#else /* HAVE_REGEXPR_H_FUNCS */
	      char *last_pos = compile(rx, buf, &buf[blen]);
#endif
	      if (reg_errno)
		{
		  free(buf);
		  if (reg_errno == 50)
		    blen += RX_INCREMENT;
		  else
		    {
		      free(pArg);
		      pArg = NULL;
		      break;
		    }
		}
	      else
		{
		  pArg->compiled_expression = buf;
		  break;
		}
	    }
	}
      while (blen <= MAX_RX_LEN);
    }
  if (pArg && !pArg->compiled_expression)
    {
      free(pArg);
      pArg = NULL;
    }
  return (void *)pArg;
#else
  return 0;
#endif
}

/*---------------------------------------------------------------------------
|   Facility      :  libnform
|   Function      :  static void *Copy_RegularExpression_Type(
|                                      const void * argp)
|
|   Description   :  Copy structure for regex type argument.
|
|   Return Values :  Pointer to argument structure or NULL on error.
+--------------------------------------------------------------------------*/
static void *
Copy_RegularExpression_Type(const void *argp)
{
#if (HAVE_REGEX_H_FUNCS | HAVE_REGEXP_H_FUNCS | HAVE_REGEXPR_H_FUNCS)
  const RegExp_Arg *ap = (const RegExp_Arg *)argp;
  const RegExp_Arg *result = (const RegExp_Arg *)0;

  if (ap)
    {
      *(ap->refCount) += 1;
      result = ap;
    }
  return (void *)result;
#else
  return 0;
#endif
}

/*---------------------------------------------------------------------------
|   Facility      :  libnform
|   Function      :  static void Free_RegularExpression_Type(void * argp)
|
|   Description   :  Free structure for regex type argument.
|
|   Return Values :  -
+--------------------------------------------------------------------------*/
static void
Free_RegularExpression_Type(void *argp)
{
#if HAVE_REGEX_H_FUNCS | HAVE_REGEXP_H_FUNCS | HAVE_REGEXPR_H_FUNCS
  RegExp_Arg *ap = (RegExp_Arg *)argp;

  if (ap)
    {
      if (--(*(ap->refCount)) == 0)
	{
#if HAVE_REGEX_H_FUNCS
	  if (ap->pRegExp)
	    {
	      free(ap->refCount);
	      regfree(ap->pRegExp);
	    }
#elif HAVE_REGEXP_H_FUNCS | HAVE_REGEXPR_H_FUNCS
	  if (ap->compiled_expression)
	    {
	      free(ap->refCount);
	      free(ap->compiled_expression);
	    }
#endif
	  free(ap);
	}
    }
#endif
}

/*---------------------------------------------------------------------------
|   Facility      :  libnform
|   Function      :  static bool Check_RegularExpression_Field(
|                                      FIELD * field,
|                                      const void  * argp)
|
|   Description   :  Validate buffer content to be a valid regular expression
|
|   Return Values :  TRUE  - field is valid
|                    FALSE - field is invalid
+--------------------------------------------------------------------------*/
static bool
Check_RegularExpression_Field(FIELD *field, const void *argp)
{
  bool match = FALSE;

#if HAVE_REGEX_H_FUNCS
  const RegExp_Arg *ap = (const RegExp_Arg *)argp;

  if (ap && ap->pRegExp)
    match = (regexec(ap->pRegExp, field_buffer(field, 0), 0, NULL, 0)
	     ? FALSE
	     : TRUE);
#elif HAVE_REGEXP_H_FUNCS | HAVE_REGEXPR_H_FUNCS
  RegExp_Arg *ap = (RegExp_Arg *)argp;

  if (ap && ap->compiled_expression)
    match = (step(field_buffer(field, 0), ap->compiled_expression)
	     ? TRUE
	     : FALSE);
#endif
  return match;
}

static FIELDTYPE typeREGEXP =
{
  _HAS_ARGS | _RESIDENT,
  1,				/* this is mutable, so we can't be const */
  (FIELDTYPE *)0,
  (FIELDTYPE *)0,
  Make_RegularExpression_Type,
  Copy_RegularExpression_Type,
  Free_RegularExpression_Type,
  Check_RegularExpression_Field,
  NULL,
  NULL,
  NULL
};

NCURSES_EXPORT_VAR(FIELDTYPE*) TYPE_REGEXP = &typeREGEXP;

/* fty_regex.c ends here */