/*************************************************************************
*									 *
*	 YAP Prolog 	%W% %G%
*									 *
*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
*									 *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-2003	 *
*									 *
**************************************************************************
*									 *
* File:		yapio.h							 *
* Last rev:	22/1/03							 *
* mods:									 *
* comments:	UNICODE encoding support (based on SWI-Prolog)		 *
*									 *
*************************************************************************/

#ifndef ENCODING_H

#define ENCODING_H 1

typedef enum {
  ENC_OCTET      = 0,  /// binary files
  ENC_ISO_LATIN1 = 1,  /// US+West Europe
  ENC_ISO_ASCII  = 2,  /// US only
  ENC_ISO_ANSI   = 4,  /// Who cares
  ENC_ISO_UTF8   = 8,  /// Most everyone nowadays
  ENC_UTF16_BE = 16, /// People who made a mistake
  ENC_UTF16_LE = 32, /// People who made the same mistake
  ENC_ISO_UTF32_BE = 64,  /// nobody
  ENC_ISO_UTF32_LE = 128, /// yes, nobody
} encoding_t;

#if defined(__BIG_ENDIAN__)
#define ENC_WCHAR ENC_ISO_UTF32_BE
#else
#define ENC_WCHAR ENC_ISO_UTF32_LE
#endif

#ifdef YAP_H

/// read the current environment, as set by the user or as Initial
encoding_t Yap_DefaultEncoding( void );
void Yap_SetDefaultEncoding(encoding_t new_encoding);

#if HAVE_XLOCALE_H
typedef enum {
  SEQ_ENC_OCTET,  /// binary files
  SEQ_ENC_ISO_LATIN1,  /// US+West Europe
  SEQ_ENC_ISO_ASCII ,  /// US only
  SEQ_ENC_ISO_ANSI  ,  /// Who cares
  SEQ_ENC_ISO_UTF8  ,  /// Most everyone nowadays
  SEQ_ENC_UTF16_BE, /// People who made a mistake
  SEQ_ENC_UTF16_LE, /// People who made the same mistake
v\  SEQ_ENC_ISO_UTF32_BE,  /// nobody
  SEQ_ENC_ISO_UTF32_LE /// yes, nobody
  } seq_encoding_t;

/// convert from unary to binary representation.
static inline seq_encoding_t seq_encoding(encoding_t inp) {
#if HAVE__BUILTIN_FFSLL
  return __builtin_ffsll(inp);
#elif HAVE_FFSLL
  return ffsll(inp);
#else
  unsigned int out;
  // supports max 16 different encodings.
  if (inp==0)
    return 0L;
  // if (inp &     ((CELL)0xffffL << 16)) {inp >>= 16; out += 16;}
  if (inp &       ((CELL)0xffL << 8)) {inp >>=  8; out +=  8;}
  if (inp &   ((CELL)0xfL << 4)) {inp >>=  4; out +=  4;}
  if (inp &        ((CELL)0x3L << 2)) {inp >>=  2; out +=  2;}
  if (inp &        ((CELL)0x1 << 1)) out++;
#endif
  return out;
}

extern xlocale enc_locales[SEQ_ENC_ISO_UTF32_LE+1];
#endif


static inline const char *enc_name(encoding_t enc)
{
  switch(enc)
    {
    case ENC_OCTET: return "octet";
    case ENC_ISO_LATIN1: return "iso_latin_1";
    case ENC_ISO_ASCII: return "ascii";
    case ENC_ISO_ANSI: return "octet";
    case ENC_ISO_UTF8: return "utf8";
    case ENC_UTF16_BE: return "utf16_be";
    case ENC_UTF16_LE: return "utf16_le";
    case ENC_ISO_UTF32_BE: return "utf32_be";
    case  ENC_ISO_UTF32_LE: return "utf32_le";
    }
}

static inline
encoding_t enc_id(char *s)
{
    {
        if (!strcmp(s,  "iso_utf8")) return ENC_ISO_UTF8;
	if (!strcmp(s,  "utf16_be")) return ENC_UTF16_BE;
        if (!strcmp(s,  "utf16_le")) return ENC_UTF16_LE;
	if (!strcmp(s,  "octet")) return ENC_OCTET;
        if (!strcmp(s,  "iso_latin_1")) return ENC_ISO_LATIN1;
        if (!strcmp(s,  "iso_ascii")) return ENC_ISO_ASCII;
        if (!strcmp(s,  "iso_ansi")) return ENC_ISO_ANSI;
        if (!strcmp(s,  "utf32_be")) return ENC_ISO_UTF32_BE;
        if (!strcmp(s,  "utf32_le")) return ENC_ISO_UTF32_LE;
        if (!strcmp(s,  "default")) return Yap_DefaultEncoding();
        else {
	  Yap_Error(DOMAIN_ERROR_OUT_OF_RANGE, 0, "bad encoding %s", s);
            return ENC_OCTET;
        }
    }
}

#endif

#endif