yap-6.3/C/text.c

/*************************************************************************
*									 *
*	 YAP Prolog 							 *
*									 *
*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
*									 *
* Copyright L.Damas, V. Santos Costa and Universidade do Porto 1985--	 *
*									 *
**************************************************************************
*									 *
* File:		strings.c						 *
* comments:	General-conversion of character sequences.		 *
*									 *
* Last rev:     $Date: 2008-07-24 16:02:00 $,$Author: vsc $	     	 *
*									 *
*************************************************************************/

#include "Yap.h"
#include "YapHeap.h"
#include "YapText.h"
#include "Yatom.h"
#include "eval.h"
#include "yapio.h"

#include <string.h>
#include <wchar.h>

#ifndef HAVE_WCSNLEN
inline static size_t min_size(size_t i, size_t j) { return (i < j ? i : j); }
#define wcsnlen(S, N) min_size(N, wcslen(S))
#endif

static inline unsigned char *getChar(unsigned char *p, int *c) {
  *c = *p;
  return p + 1;
}

static inline wchar_t *getWchar(wchar_t *p, int *c) {
  *c = *p;
  return p + 1;
}

#ifndef NAN
#define NAN (0.0 / 0.0)
#endif

static Term Globalize(Term v USES_REGS) {
  if (!IsVarTerm(v = Deref(v))) {
    return v;
  }
  if (VarOfTerm(v) > HR && VarOfTerm(v) < LCL0) {
    Bind_Local(VarOfTerm(v), MkVarTerm());
    v = Deref(v);
  }
  return v;
}

static Int SkipListCodes(unsigned char **bufp, Term *l, Term **tailp,
                         Int *atoms, bool *wide, seq_tv_t *inp USES_REGS) {
  Int length = 0;
  Term *s; /* slow */
  Term v;  /* temporary */
  *wide = false;
  size_t max = 1;
  unsigned char *st0 = *bufp, *st;
  unsigned char *smax = NULL;

  do_derefa(v, l, derefa_unk, derefa_nonvar);
  *tailp = l;
  s = l;

  if (inp->type & YAP_STRING_TRUNC) {
    max = inp->max;
  } else {
    max = 0; // basically, this will never be reached;
  }

  if (!st0) {
    if (inp->type & YAP_STRING_MALLOC) {
      *bufp = st0 = (unsigned char *)malloc(MAXPATHLEN + 1);
      smax = st0 + (MAXPATHLEN - 8); // give 8 bytes for max UTF-8 size + '\0';
    } else {
      *bufp = st0 = (unsigned char *)Yap_PreAllocCodeSpace();
      smax = (unsigned char *)AuxTop -
             8; // give 8 bytes for max UTF-8 size + '\0';
    }
  } else if (inp->sz > 0) {
    smax = st0 + (inp->sz - 8); // give 8 bytes for max UTF-8 size + '\0';
  } else {
    // AUX_ERROR( *l, 2*(length+1), st0, unsigned char);
    return 0;
  }
  *bufp = st = st0;

  if (*l == TermNil) {
    return 0;
  }
  if (IsPairTerm(*l)) {
    Term hd0 = HeadOfTerm(*l);
    if (IsVarTerm(hd0)) {
      return -INSTANTIATION_ERROR;
    }
    // are we looking for atoms/codes?
    // whatever the case, we should be consistent throughout,
    // so we should be consistent with the first arg.
    if (*atoms == 1) {
      if (!IsIntegerTerm(hd0)) {
        return -INSTANTIATION_ERROR;
      }
    } else if (*atoms == 2) {
      if (!IsAtomTerm(hd0)) {
        return -TYPE_ERROR_ATOM;
      }
    }

    do {
      int ch;
      length++;
      if (length == max) {
        *st++ = '\0';
      }
      {
        Term hd = Deref(RepPair(*l)[0]);
        if (IsVarTerm(hd)) {
          return -INSTANTIATION_ERROR;
        } else if (IsAtomTerm(hd)) {
          (*atoms)++;
          if (*atoms < length) {
            *tailp = l;
            return -TYPE_ERROR_NUMBER;
          }
          if (IsWideAtom(AtomOfTerm(hd))) {
            int ch;
            if ((RepAtom(AtomOfTerm(hd))->WStrOfAE)[1] != '\0') {
              length = -REPRESENTATION_ERROR_CHARACTER;
            }
            ch = RepAtom(AtomOfTerm(hd))->WStrOfAE[0];
            *wide = true;
          } else {
            AtomEntry *ae = RepAtom(AtomOfTerm(hd));
            if ((ae->StrOfAE)[1] != '\0') {
              length = -REPRESENTATION_ERROR_CHARACTER;
            } else {
              ch = RepAtom(AtomOfTerm(hd))->StrOfAE[0];
              *wide |= ch > 0x80;
            }
          }
        } else if (IsIntegerTerm(hd)) {
          ch = IntegerOfTerm(hd);
          if (*atoms)
            length = -TYPE_ERROR_ATOM;
          else if (ch < 0) {
            *tailp = l;
            length = -DOMAIN_ERROR_NOT_LESS_THAN_ZERO;
          } else {
            *wide |= ch > 0x80;
          }
        } else {
          length = -TYPE_ERROR_INTEGER;
        }
        if (length < 0) {
          *tailp = l;
          return length;
        }
      }
      // now copy char to buffer
      size_t chsz = put_utf8(st, ch);
      if (smax <= st + chsz) {
        *st++ = '\0';
        *tailp = l;
        return length;
      } else {
        st += chsz;
      }
      l = RepPair(*l) + 1;
      do_derefa(v, l, derefa2_unk, derefa2_nonvar);
    } while (*l != *s && IsPairTerm(*l));
  }
  if (IsVarTerm(*l)) {
    return -INSTANTIATION_ERROR;
  }
  if (*l != TermNil) {
    return -TYPE_ERROR_LIST;
  }
  st[0] = '\0';
  *tailp = l;

  return length;
}

static void *to_buffer(void *buf, Term t, seq_tv_t *inp, bool *widep,
                       Int *atoms, size_t *lenp USES_REGS) {
  CELL *r = NULL;
  Int n;

  if (!buf) {
    inp->sz = *lenp;
  }
  unsigned char *bufc = buf;
  n = SkipListCodes(&bufc, &t, &r, atoms, widep, inp PASS_REGS);
  if (n < 0) {
    LOCAL_Error_TYPE = -n;
    LOCAL_Error_Term = *r;
    return NULL;
  }
  *lenp = n;
  return bufc;
}

static void *Yap_ListOfCodesToBuffer(void *buf, Term t, seq_tv_t *inp,
                                     bool *widep, size_t *lenp USES_REGS) {
  Int atoms = 1; // we only want lists of atoms
  return to_buffer(buf, t, inp, widep, &atoms, lenp PASS_REGS);
}

static void *Yap_ListOfAtomsToBuffer(void *buf, Term t, seq_tv_t *inp,
                                     bool *widep, size_t *lenp USES_REGS) {
  Int atoms = 2; // we only want lists of integer codes
  return to_buffer(buf, t, inp, widep, &atoms, lenp PASS_REGS);
}

static void *Yap_ListToBuffer(void *buf, Term t, seq_tv_t *inp, bool *widep,
                              size_t *lenp USES_REGS) {
  Int atoms = 0; // we accept both types of lists.
  return to_buffer(buf, t, inp, widep, &atoms, lenp PASS_REGS);
}

#if USE_GEN_TYPE_ERROR
static yap_error_number gen_type_error(int flags) {
  if ((flags & (YAP_STRING_STRING | YAP_STRING_ATOM | YAP_STRING_INT |
                YAP_STRING_FLOAT | YAP_STRING_ATOMS_CODES | YAP_STRING_BIG)) ==
      (YAP_STRING_STRING | YAP_STRING_ATOM | YAP_STRING_INT | YAP_STRING_FLOAT |
       YAP_STRING_ATOMS_CODES | YAP_STRING_BIG))
    return TYPE_ERROR_TEXT;
  if ((flags & (YAP_STRING_STRING | YAP_STRING_ATOM | YAP_STRING_INT |
                YAP_STRING_FLOAT | YAP_STRING_BIG)) ==
      (YAP_STRING_STRING | YAP_STRING_ATOM | YAP_STRING_INT | YAP_STRING_FLOAT |
       YAP_STRING_BIG))
    return TYPE_ERROR_ATOMIC;
  if ((flags & (YAP_STRING_INT | YAP_STRING_FLOAT | YAP_STRING_BIG)) ==
      (YAP_STRING_INT | YAP_STRING_FLOAT | YAP_STRING_BIG))
    return TYPE_ERROR_NUMBER;
  if (flags & YAP_STRING_ATOM)
    return TYPE_ERROR_ATOM;
  if (flags & YAP_STRING_STRING)
    return TYPE_ERROR_STRING;
  if (flags & (YAP_STRING_CODES | YAP_STRING_ATOMS))
    return TYPE_ERROR_LIST;
  return TYPE_ERROR_NUMBER;
}
#endif

void *Yap_readText(void *buf, seq_tv_t *inp, encoding_t *enc, int *minimal,
                   size_t *lengp USES_REGS) {
  char *s, *s0 = buf;
  wchar_t *ws;
  bool wide;

  /* we know what the term is */
  if (!(inp->type & (YAP_STRING_CHARS | YAP_STRING_WCHARS))) {
    if (!(inp->type & YAP_STRING_TERM)) {
      if (IsVarTerm(inp->val.t)) {
        LOCAL_Error_TYPE = INSTANTIATION_ERROR;
      } else if (!IsAtomTerm(inp->val.t) && inp->type == YAP_STRING_ATOM) {
        LOCAL_Error_TYPE = TYPE_ERROR_ATOM;
      } else if (!IsStringTerm(inp->val.t) && inp->type == YAP_STRING_STRING) {
        LOCAL_Error_TYPE = TYPE_ERROR_STRING;
      } else if (!IsPairTerm(inp->val.t) && !IsStringTerm(inp->val.t) &&
                 inp->type == (YAP_STRING_ATOMS_CODES | YAP_STRING_STRING)) {
        LOCAL_Error_TYPE = TYPE_ERROR_LIST;
      } else if (!IsNumTerm(inp->val.t) &&
                 (inp->type & (YAP_STRING_INT | YAP_STRING_FLOAT |
                               YAP_STRING_BIG)) == inp->type) {
        LOCAL_Error_TYPE = TYPE_ERROR_NUMBER;
      }
      LOCAL_Error_Term = inp->val.t;
    }
  }
  if (LOCAL_Error_TYPE != YAP_NO_ERROR)
    return NULL;

  // this is a term, extract the UTF8 representation
  if (IsStringTerm(inp->val.t) && inp->type & YAP_STRING_STRING) {
    const char *s = StringOfTerm(inp->val.t);
    *enc = ENC_ISO_UTF8;
    *minimal = FALSE;
    if (lengp)
      *lengp = strlen(s);
    return (void *)s;
  }
  if (IsAtomTerm(inp->val.t) && inp->type & YAP_STRING_ATOM) {
    // this is a term, extract to a buffer, and representation is wide
    *minimal = TRUE;
    Atom at = AtomOfTerm(inp->val.t);
    if (IsWideAtom(at)) {
      ws = at->WStrOfAE;
      *lengp = wcslen(ws);
      *enc = ENC_WCHAR;
      return ws;
    } else {
      s = (char *)at->StrOfAE;
      *lengp = strlen(s);
      *enc = ENC_ISO_LATIN1;
      return s;
    }
  }
  if (((inp->type & (YAP_STRING_CODES | YAP_STRING_ATOMS)) ==
       (YAP_STRING_CODES | YAP_STRING_ATOMS))) {
    s = Yap_ListToBuffer(s0, inp->val.t, inp, &wide, lengp PASS_REGS);
    // this is a term, extract to a sfer, and representation is wide
    *minimal = true;
    *enc = ENC_ISO_UTF8;
    return s;
  }
  if (inp->type == YAP_STRING_CODES) {
    s = Yap_ListOfCodesToBuffer(s0, inp->val.t, inp, &wide, lengp PASS_REGS);
    // this is a term, extract to a sfer, and representation is wide
    *minimal = true;
    *enc = ENC_ISO_UTF8;
    return s;
  }
  if (inp->type == YAP_STRING_ATOMS) {
    s = Yap_ListOfAtomsToBuffer(s0, inp->val.t, inp, &wide, lengp PASS_REGS);
    // this is a term, extract to a buffer, and representation is wide
    *minimal = true;
    *enc = ENC_ISO_UTF8;
    return s;
  }
  if (inp->type & YAP_STRING_INT && IsIntegerTerm(inp->val.t)) {
    if (s0)
      s = s0;
    else
      s = Yap_PreAllocCodeSpace();
    AUX_ERROR(inp->val.t, LOCAL_MAX_SIZE, s, char);
    if (snprintf(s, LOCAL_MAX_SIZE - 1, Int_FORMAT, IntegerOfTerm(inp->val.t)) <
        0) {
      AUX_ERROR(inp->val.t, 2 * LOCAL_MAX_SIZE, s, char);
    }
    *enc = ENC_ISO_LATIN1;
    *lengp = strlen(s);
    return s;
  }
  if (inp->type & YAP_STRING_FLOAT && IsFloatTerm(inp->val.t)) {
    if (s0)
      s = s0;
    else
      s = Yap_PreAllocCodeSpace();
    AUX_ERROR(inp->val.t, LOCAL_MAX_SIZE, s, char);
    if (!Yap_FormatFloat(FloatOfTerm(inp->val.t), &s, LOCAL_MAX_SIZE - 1)) {
      AUX_ERROR(inp->val.t, 2 * LOCAL_MAX_SIZE, s, char);
    }
    *lengp = strlen(s);
    *enc = ENC_ISO_LATIN1;
    return s;
  }
#if USE_GMP
  if (inp->type & YAP_STRING_BIG && IsBigIntTerm(inp->val.t)) {
    if (s0)
      s = s0;
    else
      s = Yap_PreAllocCodeSpace();
    if (!Yap_mpz_to_string(Yap_BigIntOfTerm(inp->val.t), s, LOCAL_MAX_SIZE - 1,
                           10)) {
      AUX_ERROR(inp->val.t, LOCAL_MAX_SIZE, s, char);
    }
    *enc = ENC_ISO_LATIN1;
    *lengp = strlen(s);
    return s;
  }
#endif
  if (inp->type & YAP_STRING_TERM) {
    encoding_t enc = ENC_ISO_UTF8;
    char *o = Yap_TermToString(inp->val.t, lengp, enc, 0);
    return o;
  }
  if (inp->type & YAP_STRING_CHARS) {
    *enc = inp->enc;
    if (inp->type & YAP_STRING_NCHARS)
      *lengp = inp->sz;
    else
      *lengp = strlen(inp->val.c);
    return (void *)inp->val.c;
  }
  if (inp->type & YAP_STRING_WCHARS) {
    *enc = ENC_WCHAR;
    if (inp->type & YAP_STRING_NCHARS)
      *lengp = inp->sz;
    else
      *lengp = wcslen(inp->val.w);
    return (void *)inp->val.w;
  }
  return NULL;
}


static Term write_strings(void *s0, seq_tv_t *out, encoding_t enc, int minimal,
                          size_t leng USES_REGS) {
  size_t min = 0, max = leng;
  if (out->type & (YAP_STRING_NCHARS | YAP_STRING_TRUNC)) {
    if (out->type & YAP_STRING_NCHARS)
      min = out->sz;
    if (out->type & YAP_STRING_TRUNC && out->max < max)
      max = out->max;
  }

  switch (enc) {
  case ENC_ISO_UTF8: {
    unsigned char *s = s0, *lim = s + (max = strlen_utf8(s));
    Term t = init_tstring(PASS_REGS1);
    unsigned char *cp = s, *buf;

    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    buf = buf_from_tstring(HR);
    while (*cp && cp < lim) {
      utf8proc_int32_t chr;
      cp += get_utf8(cp, -1, &chr);
      buf += put_utf8(buf, chr);
    }
    if (max >= min)
      *buf++ = '\0';
    else
      while (max < min) {
        max++;
        buf += put_utf8(buf, '\0');
      }

    close_tstring(buf PASS_REGS);
    out->val.t = t;
  } break;
  case ENC_ISO_LATIN1: {
    unsigned char *s = s0, *lim = s + (max = strlen_latin_utf8(s0));
    Term t = init_tstring(PASS_REGS1);
    unsigned char *cp = s;
    unsigned char *buf;
    utf8proc_int32_t chr;

    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    buf = buf_from_tstring(HR);
    while (cp < lim) {
      cp = getChar(cp, &chr);
      buf += put_utf8(buf, chr);
    }
    if (max >= min)
      *buf++ = '\0';
    else
      while (max < min) {
        max++;
        buf += put_utf8(buf, chr);
      }
    close_tstring(buf PASS_REGS);
    out->val.t = t;
  } break;
  case ENC_WCHAR: {
    wchar_t *s = s0, *lim = s + (max = strlen_ucs2_utf8(s0));
    Term t = init_tstring(PASS_REGS1);
    wchar_t *wp = s;
    unsigned char *buf;

    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    buf = buf_from_tstring(HR);
    while (wp < lim) {
      utf8proc_int32_t chr;
      wp = getWchar(wp, &chr);
      buf += put_utf8(buf, chr);
    }
    if (max >= min)
      *buf++ = '\0';
    else
      while (max < min) {
        max++;
        buf += put_utf8(buf, '\0');
      }
    close_tstring(buf PASS_REGS);
    out->val.t = t;
  } break;
  default:
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
              enc_name(enc), __FUNCTION__);
  }

  return out->val.t;
}

static Term write_atoms(void *s0, seq_tv_t *out, encoding_t enc, int minimal,
                        size_t leng USES_REGS) {
  Term t = AbsPair(HR);
  size_t sz = 0;
  size_t max = leng;
  if (leng == 0) {
    out->val.t = t;
    return TermNil;
  }
  if (out->type & (YAP_STRING_NCHARS | YAP_STRING_TRUNC)) {
    if (out->type & YAP_STRING_TRUNC && out->max < max)
      max = out->max;
  }

  switch (enc) {
  case ENC_ISO_UTF8: {
    unsigned char *s = s0, *lim = s + strnlen((char *)s, max);
    unsigned char *cp = s;
    wchar_t w[2];
    w[1] = '\0';
    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    while (cp < lim && *cp) {
      utf8proc_int32_t chr;
      CELL *cl;
      cp += get_utf8(cp, -1, &chr);
      if (chr == '\0')
        break;
      w[0] = chr;
      cl = HR;
      HR += 2;
      cl[0] = MkAtomTerm(Yap_LookupMaybeWideAtom(w));
      cl[1] = AbsPair(HR);
      sz++;
      if (sz == max)
        break;
    }
    break;
  }
  case ENC_ISO_LATIN1: {
    unsigned char *s = s0, *lim = s + strnlen(s0, max);
    unsigned char *cp = s;
    char w[2];
    w[1] = '\0';

    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    while (cp < lim) {
      utf8proc_int32_t chr;
      cp = getChar(cp, &chr);
      if (chr == '\0')
        break;
      w[0] = chr;
      HR[0] = MkAtomTerm(Yap_LookupAtom(w));
      HR[1] = AbsPair(HR + 2);
      HR += 2;
      sz++;
      if (sz == max)
        break;
    }
    break;
  }
  case ENC_WCHAR: {
    wchar_t *s = s0, *lim = s + wcsnlen(s, max);
    wchar_t *cp = s;
    wchar_t w[2];
    w[1] = '\0';

    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    while (*cp && cp < lim) {
      utf8proc_int32_t chr;
      cp = getWchar(cp, &chr);
      if (chr == '\0')
        break;
      w[0] = chr;
      HR[0] = MkAtomTerm(Yap_LookupMaybeWideAtom(w));
      HR[1] = AbsPair(HR + 2);
      HR += 2;
      sz++;
      if (sz == max)
        break;
    }
    break;
  }
  default:
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
              enc_name(enc), __FUNCTION__);
  }
  if (out->type & YAP_STRING_DIFF) {
    if (sz == 0)
      t = out->dif;
    else
      HR[-1] = Globalize(out->dif PASS_REGS);
  } else {
    if (sz == 0)
      t = TermNil;
    else
      HR[-1] = TermNil;
  }
  out->val.t = t;
  return (t);
}

static Term write_codes(void *s0, seq_tv_t *out, encoding_t enc, int minimal,
                        size_t leng USES_REGS) {
  Term t = AbsPair(HR);
  size_t min = 0, max = leng;
  size_t sz = 0;

  if (out->type & (YAP_STRING_NCHARS | YAP_STRING_TRUNC)) {
    if (out->type & YAP_STRING_NCHARS)
      min = out->sz;
    if (out->type & YAP_STRING_TRUNC && out->max < max)
      max = out->max;
  }

  switch (enc) {
  case ENC_ISO_UTF8: {
    unsigned char *s = s0, *lim = s + strnlen(s0, max);
    unsigned char *cp = s;
    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    while (*cp && cp < lim) {
      utf8proc_int32_t chr;
      cp += get_utf8(cp, -1, &chr);
      HR[0] = MkIntTerm(chr);
      HR[1] = AbsPair(HR + 2);
      HR += 2;
      sz++;
      if (sz == max)
        break;
    }
    break;
  }
  case ENC_ISO_LATIN1: {
    unsigned char *s = s0, *lim = s + strnlen(s0, max);
    unsigned char *cp = s;

    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    while (cp < lim) {
      utf8proc_int32_t chr;
      cp = getChar(cp, &chr);
      HR[0] = MkIntTerm(chr);
      HR[1] = AbsPair(HR + 2);
      HR += 2;
      sz++;
      if (sz == max)
        break;
    }
    break;
  }
  case ENC_WCHAR: {
    wchar_t *s = s0, *lim = s + wcsnlen(s, max);
    wchar_t *cp = s;

    LOCAL_TERM_ERROR(t, 2 * (lim - s));
    while (cp < lim) {
      utf8proc_int32_t chr;
      cp = getWchar(cp, &chr);
      HR[0] = MkIntTerm(chr);
      HR[1] = AbsPair(HR + 2);
      HR += 2;
      sz++;
      if (sz == max)
        break;
    }
    break;
  }
  default:
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
              enc_name(enc), __FUNCTION__);
  }
  while (sz < min) {
    HR[0] = MkIntTerm(MkIntTerm(0));
    HR[1] = AbsPair(HR + 2);
    HR += 2;
    sz++;
  }
  if (out->type & YAP_STRING_DIFF) {
    if (sz == 0)
      t = out->dif;
    else
      HR[-1] = Globalize(out->dif PASS_REGS);
  } else {
    if (sz == 0)
      t = TermNil;
    else
      HR[-1] = TermNil;
  }
  out->val.t = t;
  return (t);
}

static Atom write_atom(void *s0, seq_tv_t *out, encoding_t enc, int minimal,
                       size_t leng USES_REGS) {
  size_t max = leng;
  if (out->type & (YAP_STRING_NCHARS | YAP_STRING_TRUNC)) {
    if (out->type & YAP_STRING_TRUNC && out->max < max)
      max = out->max;
  }

  switch (enc) {
  case ENC_ISO_UTF8: {
    unsigned char *s = s0, *lim = s + strnlen(s0, max);
    wchar_t *buf = malloc(sizeof(wchar_t) * ((lim + 2) - s)), *ptr = buf;
    Atom at;

    while (*s && s < lim) {
      utf8proc_int32_t chr;
      s += get_utf8(s, -1, &chr);
      *ptr++ = chr;
    }
    *ptr++ = '\0';
    at = Yap_LookupMaybeWideAtomWithLength(buf, max);
    free(buf);
    out->val.a = at;
    return at;
  }
  case ENC_ISO_LATIN1: {
    char *s = s0;
    Atom at;

    max = strnlen(s, max);
    at = Yap_LookupAtomWithLength(s, max);
    out->val.a = at;
    return at;
  }
  case ENC_WCHAR: {
    wchar_t *s = s0;
    Atom at;

    max = wcsnlen(s, max);
    out->val.a = at = Yap_LookupMaybeWideAtomWithLength(s, max);
    return at;
  }
  default:
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
              enc_name(enc));
  }
  return NULL;
}

static size_t write_wbuffer(void *s0, seq_tv_t *out, encoding_t enc,
                            int minimal, size_t leng USES_REGS) {
  size_t min = 0, max = leng, sz_end, sz;
  out->enc = ENC_WCHAR;
  if (out->type & (YAP_STRING_NCHARS | YAP_STRING_TRUNC)) {
    if (out->type & YAP_STRING_NCHARS)
      min = out->sz;
    if (out->type & YAP_STRING_TRUNC && out->max < max)
      max = out->max;
  }
  if (out->enc != enc ||
      out->type & (YAP_STRING_WITH_BUFFER | YAP_STRING_MALLOC)) {
    if (enc != ENC_WCHAR) {
      sz = strlen((char *)s0) + 1;
    } else {
      sz = wcslen((wchar_t *)s0) + 1;
    }
    if (sz < min)
      sz = min;
    sz *= sizeof(wchar_t);
    if (out->type & (YAP_STRING_MALLOC)) {
      out->val.w = malloc(sz);
    } else if (!(out->type & (YAP_STRING_WITH_BUFFER))) {
      if (ASP - (sz / sizeof(CELL) + 1) > HR + 1024) {
        out->val.w =
            (wchar_t *)(ASP - ((sz * sizeof(wchar_t *) / sizeof(CELL) + 1)));
      } else
        return -1;
    }
  } else {
    out->val.w = s0;
    sz_end = (wcslen(s0) + 1) * sizeof(wchar_t);
  }
  if (out->enc == ENC_WCHAR) {
    switch (enc) {
    case ENC_WCHAR:
      if (out->type & (YAP_STRING_WITH_BUFFER | YAP_STRING_MALLOC)) {
        wchar_t *s = s0;
        size_t n = wcslen(s) + 1;
        if (n < min)
          n = min;
        memcpy(out->val.c, s0, n * sizeof(wchar_t));
        out->val.w[n] = '\0';
        sz_end = n + 1;
      }
    case ENC_ISO_UTF8: {
      unsigned char *s = s0, *lim = s + (max = strnlen(s0, max));
      unsigned char *cp = s;
      wchar_t *buf0, *buf;

      buf = buf0 = out->val.w;
      if (!buf)
        return -1;
      while (*cp && cp < lim) {
        utf8proc_int32_t chr;
        cp += get_utf8(cp, -1, &chr);
        *buf++ = chr;
      }
      if (max >= min)
        *buf++ = '\0';
      else
        while (max < min) {
          utf8proc_int32_t chr;
          max++;
          cp += get_utf8(cp, -1, &chr);
          *buf++ = chr;
        }
      *buf = '\0';
      sz_end = (buf - buf0) + 1;
    } break;
    case ENC_ISO_LATIN1: {
      char *s = s0;
      size_t n = strlen(s), i;
      if (n < min)
        n = min;
      for (i = 0; i < n; i++)
        out->val.w[i] = s[i];
      out->val.w[n] = '\0';
      sz_end = n + 1;
    } break;
    default:
      sz_end = -1;
      Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
                enc_name(enc), __FUNCTION__);
    }
  }
  sz_end *= sizeof(wchar_t);
  if (out->type & (YAP_STRING_MALLOC)) {
    out->val.c = realloc(out->val.c, sz_end);
  }
  out->sz = sz_end;
  return sz_end;
}

size_t write_buffer(void *s0, seq_tv_t *out, encoding_t enc, int minimal,
                    size_t leng USES_REGS) {
  size_t min = 0, max = leng, sz_end;
  if (out->type & (YAP_STRING_NCHARS | YAP_STRING_TRUNC)) {
    if (out->type & YAP_STRING_NCHARS)
      min = out->sz;
    if (out->type & YAP_STRING_TRUNC && out->max < max)
      max = out->max;
  }
  if (out->enc != enc) {
    size_t sz;
    if (enc != ENC_WCHAR)
      sz = strlen((char *)s0) + 1;
    else
      sz = wcslen((wchar_t *)s0) + 1;
    if (sz < min)
      sz = min;
    if (!minimal)
      sz *= 4;
    if (out->type & (YAP_STRING_MALLOC)) {
      out->val.c = malloc(sz);
    } else if (!(out->type & (YAP_STRING_WITH_BUFFER))) {
      if (ASP - (sz / sizeof(CELL) + 1) > HR + 1024) {
        out->val.c = Yap_PreAllocCodeSpace();
      }
    }
  } else {
    out->val.c = s0;
  }
  if (out->enc == ENC_ISO_UTF8) {
    switch (enc) {
    case ENC_ISO_UTF8:
      if (out->type & (YAP_STRING_WITH_BUFFER | YAP_STRING_MALLOC)) {
        char *s = s0;
        size_t n = strlen(s) + 1;
        out->val.c[n] = '\0';
        sz_end = n + 1;
      } else {
        sz_end = strlen(out->val.c) + 1;
      }
      break;
    case ENC_ISO_LATIN1: {
      unsigned char *s = s0, *lim = s + (max = strnlen(s0, max));
      unsigned char *cp = s, *buf0, *buf;

      buf = buf0 = s0;
      if (!buf)
        return -1;
      while (*cp && cp < lim) {
        utf8proc_int32_t chr;
        chr = *cp++;
        buf += put_utf8(buf, chr);
      }
      if (max >= min)
        *buf++ = '\0';
      else
        while (max < min) {
          max++;
          utf8proc_int32_t chr;
          chr = *cp++;
          buf += put_utf8(buf, chr);
        }
      buf[0] = '\0';
      sz_end = (buf + 1) - buf0;
    } break;
    case ENC_WCHAR: {
      wchar_t *s = s0;
      unsigned char *buf = out->val.uc;
      size_t n = wcslen(s), i;
      if (n < min)
        n = min;
      for (i = 0; i < n; i++) {
        utf8proc_int32_t chr = s[i];
        buf += put_utf8(buf, chr);
      }
      *buf++ = '\0';
      sz_end = (buf + 1) - out->val.uc;
    } break;
    default:
      sz_end = -1;
      Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
                enc_name(enc), __FUNCTION__);
    }
  } else if (out->enc == ENC_ISO_LATIN1) {
    switch (enc) {
    case ENC_ISO_LATIN1:
      if (out->type & YAP_STRING_WITH_BUFFER) {
        char *s = s0;
        size_t n = strlen(s), i;
        if (n < min)
          n = min;
        memcpy(out->val.c, s0, n);
        for (i = 0; i < n; i++)
          out->val.w[i] = s[i];
        out->val.w[n] = '\0';
        sz_end = (n + 1) * sizeof(wchar_t);
      } else {
        sz_end = strlen(out->val.c) + 1;
      }
      break;
    case ENC_ISO_UTF8: {
      unsigned char *s = s0, *lim = s + (max = strnlen(s0, max));
      unsigned char *cp = s;
      unsigned char *buf0, *buf;

      buf = buf0 = out->val.uc;
      if (!buf)
        return -1;
      while (*cp && cp < lim) {
        utf8proc_int32_t chr;
        cp += get_utf8(cp, -1, &chr);
        *buf++ = chr;
      }
      if (max >= min)
        *buf++ = '\0';
      else
        while (max < min) {
          utf8proc_int32_t chr;
          max++;
          cp += get_utf8(cp, -1, &chr);
          *buf++ = chr;
        }
      sz_end = buf - out->val.uc;
    } break;
    case ENC_WCHAR: {
      wchar_t *s = s0;
      size_t n = wcslen(s), i;
      if (n < min)
        n = min;
      for (i = 0; i < n; i++)
        out->val.c[i] = s[i];
      out->val.c[n] = '\0';
      sz_end = n + 1;
    } break;
    default:
      sz_end = -1;
      Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
                enc_name(enc), __FUNCTION__);
    }
  } else {
    // no other encodings are supported.
    sz_end = -1;
  }
  if (out->type & (YAP_STRING_MALLOC)) {
    out->val.c = realloc(out->val.c, sz_end);
  }
  out->sz = sz_end;
  return sz_end;
}

static size_t write_length(void *s0, seq_tv_t *out, encoding_t enc, int minimal,
                           size_t leng USES_REGS) {
  size_t max = -1;

  if (out->type & (YAP_STRING_NCHARS | YAP_STRING_TRUNC)) {
    if (out->type & YAP_STRING_NCHARS && out->sz != (size_t)-1)
      return out->sz;
    if (out->type & YAP_STRING_TRUNC)
      max = out->max;
  }

  switch (enc) {
  case ENC_ISO_UTF8: {
    const unsigned char *s = s0;
    return strlen_utf8(s);
  }
  case ENC_ISO_LATIN1: {
    const char *s = s0;
    return strnlen(s, max);
  }
  case ENC_WCHAR: {
    const wchar_t *s = s0;
    return wcsnlen(s, max);
  }
  default:
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
              enc_name(enc), __FUNCTION__);
  }
  return (size_t)-1;
}

static Term write_number(void *s0, seq_tv_t *out, encoding_t enc, int minimal,
                         int size USES_REGS) {
  return Yap_StringToNumberTerm(s0, &enc);
}

static Term string_to_term(void *s0, seq_tv_t *out, encoding_t enc, int minimal,
                           size_t leng USES_REGS) {
  Term o = out->val.t =
      Yap_StringToTerm(s0, strlen(s0) + 1, &enc, GLOBAL_MaxPriority, NULL);
  return o;
}

bool write_Text(void *inp, seq_tv_t *out, encoding_t enc, int minimal,
               size_t leng USES_REGS) {
  /* we know what the term is */
  switch (out->type & YAP_TYPE_MASK) {
  case YAP_STRING_STRING:
    out->val.t = write_strings(inp, out, enc, minimal, leng PASS_REGS);
    return out->val.t != 0;
  case YAP_STRING_ATOMS:
    out->val.t = write_atoms(inp, out, enc, minimal, leng PASS_REGS);
    return out->val.t != 0;
  case YAP_STRING_CODES:
    out->val.t = write_codes(inp, out, enc, minimal, leng PASS_REGS);
    return out->val.t != 0;
  case YAP_STRING_LENGTH:
    out->val.l = write_length(inp, out, enc, minimal, leng PASS_REGS);
    return out->val.l != (size_t)(-1);
  case YAP_STRING_ATOM:
    out->val.a = write_atom(inp, out, enc, minimal, leng PASS_REGS);
    return out->val.a != NULL;
  case YAP_STRING_INT | YAP_STRING_FLOAT | YAP_STRING_BIG:
    out->val.t = write_number(inp, out, enc, minimal, leng PASS_REGS);
    return out->val.t != 0;
  case YAP_STRING_CHARS: {
    size_t sz = write_buffer(inp, out, enc, minimal, leng PASS_REGS);
    return ((Int)sz > 0);
  }
  case YAP_STRING_WCHARS: {
    size_t sz = write_wbuffer(inp, out, enc, minimal, leng PASS_REGS);
    return ((Int)sz > 0);
  }
  default:
    if (!(out->type & YAP_STRING_TERM))
      return 0;
    if (out->type & (YAP_STRING_INT | YAP_STRING_FLOAT | YAP_STRING_BIG))
      if ((out->val.t = write_number(inp, out, enc, minimal, leng PASS_REGS)) !=
          0L)
        return out->val.t != 0;
    if (out->type & (YAP_STRING_ATOM))
      if (write_atom(inp, out, enc, minimal, leng PASS_REGS) != NIL) {
        Atom at = out->val.a;
        if (at != NIL)
          out->val.t = MkAtomTerm(at);
        return at != NIL;
      }
    if ((out->val.t = string_to_term(inp, out, enc, minimal, leng PASS_REGS)) !=
        0L)
      return out->val.t != 0;
  }
  return false;
}


static size_t upcase(void *s0, seq_tv_t *out, encoding_t enc USES_REGS) {
  size_t max = -1;


  switch (enc) {
    case ENC_ISO_UTF8: {
      unsigned char *s = s0;
      while (*s) {
        // assumes the two code have always the same size;
        utf8proc_int32_t chr;
        get_utf8(s, -1, &chr);
        chr = utf8proc_toupper(chr);
        s += put_utf8(s, chr);
      }
      return true;
    }

    case ENC_ISO_LATIN1: {
      unsigned char *s = s0;
      utf8proc_int32_t chr;

      while ((chr = *s)) {
        // assumes the two code have always the same size;
        chr = *s;
        chr = utf8proc_toupper(chr);
        *s++ = chr;
      }
      return true;
    }

    case ENC_WCHAR: {
      wchar_t *s = s0;
      utf8proc_int32_t chr;

      while ((chr = *s)) {
        // assumes the two code have always the same size;
        chr = *s;
        chr = utf8proc_toupper(chr);
        *s++ = chr;
      }
      return true;
    }
    default:
      Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
                enc_name(enc), __FUNCTION__);

  }
  return false;
}

static size_t downcase(void *s0, seq_tv_t *out, encoding_t enc USES_REGS) {
  size_t max = -1;


  switch (enc) {
    case ENC_ISO_UTF8: {
      unsigned char *s = s0;
      while (*s) {
        // assumes the two code have always the same size;
        utf8proc_int32_t chr;
        get_utf8(s, -1, &chr);
        chr = utf8proc_tolower(chr);
        s += put_utf8(s, chr);
      }
      return true;
    }

    case ENC_ISO_LATIN1: {
      unsigned char *s = s0;
      utf8proc_int32_t chr;

      while ((chr = *s)) {
        // assumes the two code have always the same size;
        chr = *s;
        chr = utf8proc_tolower(chr);
        *s++ = chr;
      }
      return true;
    }
    case ENC_WCHAR: {
      wchar_t *s = s0;
      utf8proc_int32_t chr;

      while ((chr = *s)) {
        // assumes the two code have always the same size;
        chr = *s;
        chr = utf8proc_tolower(chr);
        *s++ = chr;
      }
      return true;
    }
    default:
      Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
                enc_name(enc), __FUNCTION__);

  }
  return false;
}

int Yap_CVT_Text(seq_tv_t *inp, seq_tv_t *out USES_REGS) {
  encoding_t enc;
  int minimal = FALSE;
            char *buf;
  size_t leng;

  buf = Yap_readText(NULL, inp, &enc, &minimal, &leng PASS_REGS);
  if (!buf)
    return 0L;
  if (out->type & (YAP_STRING_UPCASE|YAP_STRING_DOWNCASE)) {
    if (out->type & YAP_STRING_UPCASE) {
      if (!upcase(buf, out, enc))
        return false;
    }
    if (out->type & YAP_STRING_DOWNCASE) {
      if (!downcase(buf, out, enc))
        return false;
    }
  }

  return write_Text(buf, out, enc, minimal, leng PASS_REGS);
}

static void *compute_end(void *s0, encoding_t enc) {
  switch (enc) {
  case ENC_ISO_LATIN1:
  case ENC_ISO_UTF8: {
    char *s = (char *)s0;
    return s + (1 + strlen(s));
  }
  case ENC_WCHAR: {
    wchar_t *s = (wchar_t *)s0;
    return s + (1 + wcslen(s));
  }
  default:
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
              enc_name(enc), __FUNCTION__);
  }
  return NULL;
}

static void *advance_Text(void *s, int l, encoding_t enc) {
  switch (enc) {
  case ENC_ISO_LATIN1:
    return ((char *)s) + l;
  case ENC_ISO_UTF8:
    return (char *)skip_utf8(s, l);
  case ENC_WCHAR:
    return ((wchar_t *)s) + l;
  default:
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
              enc_name(enc), __FUNCTION__);
  }
  return s;
}

static int cmp_Text(void *s1, void *s2, int l, encoding_t enc1,
                    encoding_t enc2) {
  Int i;
  switch (enc1) {
  case ENC_ISO_LATIN1: {
    char *w1 = (char *)s1;
    switch (enc2) {
    case ENC_ISO_LATIN1:
      return strncmp(s1, s2, l);
    case ENC_ISO_UTF8: {
      utf8proc_int32_t chr1, chr2;
      unsigned char *w2 = s2;
      for (i = 0; i < l; i++) {
        chr1 = *w1++;
        w2 += get_utf8(w2, -1, &chr2);
        if (chr1 - chr2)
          return chr1 - chr2;
      }
    }
      return 0;
    case ENC_WCHAR: {
      utf8proc_int32_t chr1, chr2;
      wchar_t *w2 = s2;
      for (i = 0; i < l; i++) {
        chr1 = *w1++;
        chr2 = *w2++;
        if (chr1 - chr2)
          return chr1 - chr2;
      }
    }
      return 0;
    default:
      Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
                enc_name(enc2), __FUNCTION__);
    }
  }
  case ENC_ISO_UTF8: {
    unsigned char *w1 = s1;
    switch (enc2) {
    case ENC_ISO_LATIN1: {
      utf8proc_int32_t chr1, chr2;
      unsigned char *w2 = s2;
      for (i = 0; i < l; i++) {
        chr2 = *w2++;
        w1 += get_utf8(w1, -1, &chr1);
        if (chr1 - chr2)
          return chr1 - chr2;
      }
    }
      return 0;
    case ENC_ISO_UTF8: {
      utf8proc_int32_t chr1, chr2;
      unsigned char *w2 = s2;
      for (i = 0; i < l; i++) {
        w2 += get_utf8(w2, -1, &chr2);
        w1 += get_utf8(w1, -1, &chr1);
        if (chr1 - chr2)
          return chr1 - chr2;
      }
    }
      return 0;
    case ENC_WCHAR: {
      utf8proc_int32_t chr1, chr2;
      wchar_t *w2 = s2;
      for (i = 0; i < l; i++) {
        chr2 = *w2++;
        w1 += get_utf8(w1, -1, &chr1);
        if (chr1 - chr2)
          return chr1 - chr2;
      }
    }
      return 0;
    default:
      Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
                enc_name(enc2), __FUNCTION__);
    }
  }
  case ENC_WCHAR: {
    wchar_t *w1 = (wchar_t *)s1;
    switch (enc2) {
    case ENC_ISO_LATIN1: {
      utf8proc_int32_t chr1, chr2;
      char *w2 = s2;
      for (i = 0; i < l; i++) {
        chr1 = *w1++;
        chr2 = *w2++;
        if (chr1 - chr2)
          return chr1 - chr2;
      }
    }
      return 0;
    case ENC_ISO_UTF8: {
      utf8proc_int32_t chr1, chr2;
      unsigned char *w2 = s2;
      for (i = 0; i < l; i++) {
        chr1 = *w1++;
        w2 += get_utf8(w2, -1, &chr2);
        if (chr1 - chr2)
          return chr1 - chr2;
      }
    }
      return 0;
    case ENC_WCHAR:
      return wcsncmp(s1, s2, l);
    default:
      Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
                enc_name(enc2), __FUNCTION__);
    }
  }
  default:
    Yap_Error(SYSTEM_ERROR_INTERNAL, TermNil, "Unsupported Encoding ~s in %s",
              enc_name(enc1), __FUNCTION__);
  }
  return 0;
}

static void *concat(int n, seq_tv_t *out, void *sv[], encoding_t encv[],
                    size_t lengv[] USES_REGS) {
  if (out->type == YAP_STRING_STRING) {
    /* we assume we concatenate strings only, or ASCII stuff like numbers */
    Term t = init_tstring(PASS_REGS1);
    unsigned char *buf = buf_from_tstring(HR);
    int i;
    for (i = 0; i < n; i++) {
      if (encv[i] == ENC_WCHAR) {
        wchar_t *ptr = sv[i];
        utf8proc_int32_t chr;
        while ((chr = *ptr++))
          buf += put_utf8(buf, chr);
      } else if (encv[i] == ENC_ISO_LATIN1) {
        char *ptr = sv[i];
        utf8proc_int32_t chr;
        while ((chr = *ptr++))
          buf += put_utf8(buf, chr);
      } else {
        char *ptr = sv[i];
        utf8proc_int32_t chr;
        while ((chr = *ptr++))
          *buf++ = chr;
      }
    }
    *buf++ = '\0';
    close_tstring(buf PASS_REGS);
    out->val.t = t;
    return HR;
  } else {
    encoding_t enc = ENC_ISO_LATIN1;
    size_t sz = 0;

    int i;
    for (i = 0; i < n; i++) {
      if (encv[i] != ENC_ISO_LATIN1) {
        enc = ENC_WCHAR;
      }
      sz += write_length(sv[i], out, encv[i], FALSE, lengv[i] PASS_REGS);
    }
    if (enc == ENC_WCHAR) {
      /* wide atom */
      wchar_t *buf = (wchar_t *)HR;
      Atom at;
      LOCAL_ERROR(MkAtomTerm(Yap_LookupWideAtom(buf)), sz + 3);
      for (i = 0; i < n; i++) {
        if (encv[i] == ENC_WCHAR) {
          wchar_t *ptr = sv[i];
          utf8proc_int32_t chr;
          while ((chr = *ptr++) != '\0')
            *buf++ = chr;
        } else if (encv[i] == ENC_ISO_LATIN1) {
          char *ptr = sv[i];
          utf8proc_int32_t chr;
          while ((chr = *ptr++) != '\0')
            *buf++ = (unsigned char)chr;
        } else {
          unsigned char *ptr = sv[i];
          utf8proc_int32_t chr;
          while ((ptr += get_utf8(ptr, -1, &chr)) != NULL) {
            if (chr == '\0')
              break;
            else
              *buf++ = chr;
          }
        }
      }
      *buf++ = '\0';
      at = out->val.a = Yap_LookupWideAtom((wchar_t *)HR);
      return at;
    } else {
      /* atom */
      char *buf = (char *)HR;
      Atom at;

      LOCAL_ERROR(MkAtomTerm(Yap_LookupAtom(buf)), sz / sizeof(CELL) + 3);
      for (i = 0; i < n; i++) {
        char *ptr = sv[i];
        utf8proc_int32_t chr;
        while ((chr = *ptr++) != '\0')
          *buf++ = chr;
      }
      *buf++ = '\0';
      at = out->val.a = Yap_LookupAtom((const char *)HR);
      return at;
    }
  }
  return NULL;
}

static void *slice(size_t min, size_t max, void *buf, seq_tv_t *out,
                   encoding_t enc USES_REGS) {
  if (out->type == YAP_STRING_STRING) {
    /* we assume we concatenate strings only, or ASCII stuff like numbers */
    Term t = init_tstring(PASS_REGS1);
    unsigned char *nbuf = buf_from_tstring(HR);
    if (enc == ENC_WCHAR) {
      wchar_t *ptr = (wchar_t *)buf + min;
      utf8proc_int32_t chr;
      while (min++ < max) {
        chr = *ptr++;
        nbuf += put_utf8(nbuf, chr);
      }
    } else if (enc == ENC_ISO_LATIN1) {
      unsigned char *ptr = (unsigned char *)buf + min;
      utf8proc_int32_t chr;
      while (min++ < max) {
        chr = *ptr++;
        nbuf += put_utf8(nbuf, chr);
      }
    } else {
      unsigned char *ptr = skip_utf8(buf, min);
      utf8proc_int32_t chr;
      if (!ptr)
        return NULL;
      while (min++ < max) {
        ptr += get_utf8(ptr, -1, &chr);
        nbuf += put_utf8(nbuf, chr);
      }
    }
    *nbuf++ = '\0';
    close_tstring(nbuf PASS_REGS);
    out->val.t = t;
    return (void *)StringOfTerm(t);
  } else {
    Atom at;
    /* atom */
    if (enc == ENC_WCHAR) {
      /* wide atom */
      wchar_t *nbuf = (wchar_t *)HR;
      wchar_t *ptr = (wchar_t *)buf + min;
      if (max > min) {
        LOCAL_ERROR(MkAtomTerm(Yap_LookupWideAtom(buf)),
                    (max - min) * sizeof(wchar_t));
        memcpy(nbuf, ptr, (max - min) * sizeof(wchar_t));
      }
      nbuf[max - min] = '\0';
      at = Yap_LookupMaybeWideAtom(nbuf);
    } else if (enc == ENC_ISO_LATIN1) {
      /*  atom */
      char *nbuf = (char *)HR;

      if (max > min) {
        char *ptr = (char *)buf + min;
        LOCAL_ERROR(MkAtomTerm(Yap_LookupAtom(buf)), max - min);
        memcpy(nbuf, ptr, (max - min));
      }
      nbuf[max - min] = '\0';
      at = Yap_LookupAtom(nbuf);
    } else {
      /*  atom */
      wchar_t *nbuf = (wchar_t *)HR;
      unsigned char *ptr = skip_utf8((unsigned char *)buf, min);
      utf8proc_int32_t chr;

      LOCAL_ERROR(MkAtomTerm(Yap_LookupAtom(buf)), max - min);
      while (min++ < max) {
        ptr += get_utf8(ptr, -1, &chr);
        *nbuf++ = chr;
      }
      nbuf[0] = '\0';
      at = Yap_LookupMaybeWideAtom((wchar_t *)HR);
    }
    out->val.a = at;
    return at->StrOfAE;
  }
  return NULL;
}

//
// Out must be an atom or a string
void *Yap_Concat_Text(int n, seq_tv_t inp[], seq_tv_t *out USES_REGS) {
  encoding_t *encv;
  void **bufv;
  int minimal = FALSE;
  void *buf;
  size_t leng, *lengv;
  int i;
  Term t = ARG1;
  bufv = (void **)malloc(n * sizeof(void *));
  HEAP_TERM_ERROR(bufv, void *);
  encv = (encoding_t *)malloc(n * sizeof(encoding_t));
  HEAP_ERROR(encv, encoding_t);
  buf = NULL;
  for (i = 0; i < n; i++) {
    void *nbuf =
        Yap_readText(buf, inp + i, encv + i, &minimal, &leng PASS_REGS);

    if (!nbuf)
      return 0L;
    bufv[i] = nbuf;
    if ((char *)nbuf >= AuxBase && (char *)nbuf < AuxTop) {
      buf = compute_end(nbuf, encv[i]);
    }
  }
  lengv = (size_t *)malloc(n * sizeof(size_t));
  HEAP_ERROR(lengv, size_t);
  buf = concat(n, out, bufv, encv, lengv PASS_REGS);
  free(bufv);
  free(lengv);
  free(encv);
  return buf;
}

//
// out must be an atom or a string
void *Yap_Splice_Text(int n, size_t cuts[], seq_tv_t *inp, encoding_t encv[],
                      seq_tv_t outv[] USES_REGS) {
  encoding_t enc;
  int minimal = FALSE;
  void *buf, *store;
  size_t l, leng;
  int i, min;

  buf = Yap_readText(NULL, inp, &enc, &minimal, &leng PASS_REGS);
  if (!buf)
    return NULL;
  l = write_length(buf, inp, enc, minimal, leng PASS_REGS);
  /* where to allocate next is the most complicated part */
  if ((char *)buf >= AuxBase && (char *)buf < AuxTop) {
    store = compute_end(buf, enc);
  } else {
    store = NULL;
  }

  if (!cuts) {
    if (n == 2) {
      size_t l0, l1;
      size_t leng0, leng1;
      encoding_t enc0, enc1;
      int minimal0, minimal1;
      void *buf0, *buf1;

      if (outv[0].val.t) {
        buf0 = Yap_readText(store, outv, &enc0, &minimal0, &leng0 PASS_REGS);
        if (!buf0)
          return NULL;
        l0 = write_length(buf0, outv, enc, minimal0, leng0 PASS_REGS);
        if (cmp_Text(buf, buf0, l0, enc, enc0) != 0)
          return NULL;

        l1 = l - l0;

        buf1 = slice(l0, l, buf, outv + 1, enc PASS_REGS);
        if (encv)
          encv[1] = enc;
        return buf1;
      } else /* if (outv[1].val.t) */ {
        buf1 =
            Yap_readText(store, outv + 1, &enc1, &minimal1, &leng1 PASS_REGS);
        if (!buf1)
          return NULL;
        l1 = write_length(buf1, outv + 1, enc1, minimal1, leng1 PASS_REGS);
        if (l < l1)
          return NULL;
        l0 = l - l1;
        if (cmp_Text(advance_Text(buf, l0, enc), buf1, l1, enc, enc1) != 0)
          return NULL;
        buf0 = slice(0, l0, buf, outv, enc PASS_REGS);
        if (encv)
          encv[0] = enc;
        return buf0;
      }
    }
  }
  for (i = 0; i < n; i++) {
    if (i == 0)
      min = 0;
    else
      min = cuts[i - 1];
    slice(min, cuts[i], buf, outv + i, enc PASS_REGS);
    if (!(outv[i].val.a))
      return NULL;
    if (encv)
      encv[i] = enc;
  }
  return (void *)outv;
  ;
}

/**
 * Function to convert a generic text term (string, atom, list of codes, list of
atoms)  into a buff
er.
 *
 * @param t     the term
 * @param buf   the buffer, if NULL a buffer is malloced, and the user should
reclai it
 * @param len   buffer size
 * @param enc   encoding (UTF-8 is strongly recommended)
 *
 * @return the buffer, or NULL in case of failure. If so, Yap_Error may be
called.
 */
const char *Yap_TextTermToText(Term t, char *buf, size_t len, encoding_t enc) {
  CACHE_REGS
  seq_tv_t inp, out;

  inp.val.t = t;
  if (IsAtomTerm(t)) {
    inp.type = YAP_STRING_ATOM;
    if (IsWideAtom(AtomOfTerm(t)))
      inp.enc = ENC_WCHAR;
    else
      inp.enc = ENC_ISO_LATIN1;
  } else if (IsStringTerm(t)) {
    inp.type = YAP_STRING_STRING;
    inp.enc = ENC_ISO_UTF8;
  } else if (IsPairTerm(t)) {
    inp.type = (YAP_STRING_CODES | YAP_STRING_ATOMS);
  } else {
    Yap_Error(TYPE_ERROR_TEXT, t, NULL);
    return false;
  }
  out.enc = enc;
  out.type = YAP_STRING_CHARS;
  if (!buf) {
    inp.type |= YAP_STRING_MALLOC;
    out.type |= YAP_STRING_MALLOC;
  }
  out.val.c = buf;
  if (!Yap_CVT_Text(&inp, &out PASS_REGS))
    return NULL;
  return out.val.c;
}

/**
 * Convert from a text buffer (8-bit) to a term that has the same type as
 * _Tguide_
 *
 * @param s        the buffer
 * @param tguide   the guide
 *
 * @return the term
 */
Term Yap_MkTextTerm(const char *s, encoding_t enc, Term tguide) {
  CACHE_REGS
  if (IsAtomTerm(tguide))
    return MkAtomTerm(Yap_LookupAtom(s));
  if (IsStringTerm(tguide))
    return MkStringTerm(s);
  if (IsPairTerm(tguide) && IsAtomTerm(HeadOfTerm(tguide))) {
    return Yap_CharsToListOfAtoms(s, enc PASS_REGS);
  }
  return Yap_CharsToListOfCodes(s, enc PASS_REGS);
}