1 files changed, 1742 insertions, 0 deletions

diff --git a/gl/regex_internal.c b/gl/regex_internal.c
new file mode 100644
index 00000000..78e16f33
--- /dev/null
+++ b/gl/regex_internal.c
@@ -0,0 +1,1742 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <isamu@yamato.ibm.com>.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+static void re_string_construct_common (const char *str, Idx len,
+                                        re_string_t *pstr,
+                                        RE_TRANSLATE_TYPE trans, bool icase,
+                                        const re_dfa_t *dfa) internal_function;
+static re_dfastate_t *create_ci_newstate (const re_dfa_t *dfa,
+                                          const re_node_set *nodes,
+                                          re_hashval_t hash) internal_function;
+static re_dfastate_t *create_cd_newstate (const re_dfa_t *dfa,
+                                          const re_node_set *nodes,
+                                          unsigned int context,
+                                          re_hashval_t hash) internal_function;
+
+/* Functions for string operation.  */
+
+/* This function allocate the buffers.  It is necessary to call
+   re_string_reconstruct before using the object.  */
+
+static reg_errcode_t
+internal_function
+re_string_allocate (re_string_t *pstr, const char *str, Idx len, Idx init_len,
+                    RE_TRANSLATE_TYPE trans, bool icase, const re_dfa_t *dfa)
+{
+  reg_errcode_t ret;
+  Idx init_buf_len;
+
+  /* Ensure at least one character fits into the buffers.  */
+  if (init_len < dfa->mb_cur_max)
+    init_len = dfa->mb_cur_max;
+  init_buf_len = (len + 1 < init_len) ? len + 1: init_len;
+  re_string_construct_common (str, len, pstr, trans, icase, dfa);
+
+  ret = re_string_realloc_buffers (pstr, init_buf_len);
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+
+  pstr->word_char = dfa->word_char;
+  pstr->word_ops_used = dfa->word_ops_used;
+  pstr->mbs = pstr->mbs_allocated ? pstr->mbs : (unsigned char *) str;
+  pstr->valid_len = (pstr->mbs_allocated || dfa->mb_cur_max > 1) ? 0 : len;
+  pstr->valid_raw_len = pstr->valid_len;
+  return REG_NOERROR;
+}
+
+/* This function allocate the buffers, and initialize them.  */
+
+static reg_errcode_t
+internal_function
+re_string_construct (re_string_t *pstr, const char *str, Idx len,
+                     RE_TRANSLATE_TYPE trans, bool icase, const re_dfa_t *dfa)
+{
+  reg_errcode_t ret;
+  memset (pstr, '\0', sizeof (re_string_t));
+  re_string_construct_common (str, len, pstr, trans, icase, dfa);
+
+  if (len > 0)
+    {
+      ret = re_string_realloc_buffers (pstr, len + 1);
+      if (BE (ret != REG_NOERROR, 0))
+        return ret;
+    }
+  pstr->mbs = pstr->mbs_allocated ? pstr->mbs : (unsigned char *) str;
+
+  if (icase)
+    {
+#ifdef RE_ENABLE_I18N
+      if (dfa->mb_cur_max > 1)
+        {
+          while (1)
+            {
+              ret = build_wcs_upper_buffer (pstr);
+              if (BE (ret != REG_NOERROR, 0))
+                return ret;
+              if (pstr->valid_raw_len >= len)
+                break;
+              if (pstr->bufs_len > pstr->valid_len + dfa->mb_cur_max)
+                break;
+              ret = re_string_realloc_buffers (pstr, pstr->bufs_len * 2);
+              if (BE (ret != REG_NOERROR, 0))
+                return ret;
+            }
+        }
+      else
+#endif /* RE_ENABLE_I18N  */
+        build_upper_buffer (pstr);
+    }
+  else
+    {
+#ifdef RE_ENABLE_I18N
+      if (dfa->mb_cur_max > 1)
+        build_wcs_buffer (pstr);
+      else
+#endif /* RE_ENABLE_I18N  */
+        {
+          if (trans != NULL)
+            re_string_translate_buffer (pstr);
+          else
+            {
+              pstr->valid_len = pstr->bufs_len;
+              pstr->valid_raw_len = pstr->bufs_len;
+            }
+        }
+    }
+
+  return REG_NOERROR;
+}
+
+/* Helper functions for re_string_allocate, and re_string_construct.  */
+
+static reg_errcode_t
+internal_function
+re_string_realloc_buffers (re_string_t *pstr, Idx new_buf_len)
+{
+#ifdef RE_ENABLE_I18N
+  if (pstr->mb_cur_max > 1)
+    {
+      wint_t *new_wcs;
+
+      /* Avoid overflow.  */
+      size_t max_object_size = MAX (sizeof (wint_t), sizeof (Idx));
+      if (BE (SIZE_MAX / max_object_size < new_buf_len, 0))
+        return REG_ESPACE;
+
+      new_wcs = re_realloc (pstr->wcs, wint_t, new_buf_len);
+      if (BE (new_wcs == NULL, 0))
+        return REG_ESPACE;
+      pstr->wcs = new_wcs;
+      if (pstr->offsets != NULL)
+        {
+          Idx *new_offsets = re_realloc (pstr->offsets, Idx, new_buf_len);
+          if (BE (new_offsets == NULL, 0))
+            return REG_ESPACE;
+          pstr->offsets = new_offsets;
+        }
+    }
+#endif /* RE_ENABLE_I18N  */
+  if (pstr->mbs_allocated)
+    {
+      unsigned char *new_mbs = re_realloc (pstr->mbs, unsigned char,
+                                           new_buf_len);
+      if (BE (new_mbs == NULL, 0))
+        return REG_ESPACE;
+      pstr->mbs = new_mbs;
+    }
+  pstr->bufs_len = new_buf_len;
+  return REG_NOERROR;
+}
+
+
+static void
+internal_function
+re_string_construct_common (const char *str, Idx len, re_string_t *pstr,
+                            RE_TRANSLATE_TYPE trans, bool icase,
+                            const re_dfa_t *dfa)
+{
+  pstr->raw_mbs = (const unsigned char *) str;
+  pstr->len = len;
+  pstr->raw_len = len;
+  pstr->trans = trans;
+  pstr->icase = icase;
+  pstr->mbs_allocated = (trans != NULL || icase);
+  pstr->mb_cur_max = dfa->mb_cur_max;
+  pstr->is_utf8 = dfa->is_utf8;
+  pstr->map_notascii = dfa->map_notascii;
+  pstr->stop = pstr->len;
+  pstr->raw_stop = pstr->stop;
+}
+
+#ifdef RE_ENABLE_I18N
+
+/* Build wide character buffer PSTR->WCS.
+   If the byte sequence of the string are:
+     <mb1>(0), <mb1>(1), <mb2>(0), <mb2>(1), <sb3>
+   Then wide character buffer will be:
+     <wc1>   , WEOF    , <wc2>   , WEOF    , <wc3>
+   We use WEOF for padding, they indicate that the position isn't
+   a first byte of a multibyte character.
+
+   Note that this function assumes PSTR->VALID_LEN elements are already
+   built and starts from PSTR->VALID_LEN.  */
+
+static void
+internal_function
+build_wcs_buffer (re_string_t *pstr)
+{
+#ifdef _LIBC
+  unsigned char buf[MB_LEN_MAX];
+  assert (MB_LEN_MAX >= pstr->mb_cur_max);
+#else
+  unsigned char buf[64];
+#endif
+  mbstate_t prev_st;
+  Idx byte_idx, end_idx, remain_len;
+  size_t mbclen;
+
+  /* Build the buffers from pstr->valid_len to either pstr->len or
+     pstr->bufs_len.  */
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+  for (byte_idx = pstr->valid_len; byte_idx < end_idx;)
+    {
+      wchar_t wc;
+      const char *p;
+
+      remain_len = end_idx - byte_idx;
+      prev_st = pstr->cur_state;
+      /* Apply the translation if we need.  */
+      if (BE (pstr->trans != NULL, 0))
+        {
+          int i, ch;
+
+          for (i = 0; i < pstr->mb_cur_max && i < remain_len; ++i)
+            {
+              ch = pstr->raw_mbs [pstr->raw_mbs_idx + byte_idx + i];
+              buf[i] = pstr->mbs[byte_idx + i] = pstr->trans[ch];
+            }
+          p = (const char *) buf;
+        }
+      else
+        p = (const char *) pstr->raw_mbs + pstr->raw_mbs_idx + byte_idx;
+      mbclen = mbrtowc (&wc, p, remain_len, &pstr->cur_state);
+      if (BE (mbclen == (size_t) -2, 0))
+        {
+          /* The buffer doesn't have enough space, finish to build.  */
+          pstr->cur_state = prev_st;
+          break;
+        }
+      else if (BE (mbclen == (size_t) -1 || mbclen == 0, 0))
+        {
+          /* We treat these cases as a singlebyte character.  */
+          mbclen = 1;
+          wc = (wchar_t) pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
+          if (BE (pstr->trans != NULL, 0))
+            wc = pstr->trans[wc];
+          pstr->cur_state = prev_st;
+        }
+
+      /* Write wide character and padding.  */
+      pstr->wcs[byte_idx++] = wc;
+      /* Write paddings.  */
+      for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
+        pstr->wcs[byte_idx++] = WEOF;
+    }
+  pstr->valid_len = byte_idx;
+  pstr->valid_raw_len = byte_idx;
+}
+
+/* Build wide character buffer PSTR->WCS like build_wcs_buffer,
+   but for REG_ICASE.  */
+
+static reg_errcode_t
+internal_function
+build_wcs_upper_buffer (re_string_t *pstr)
+{
+  mbstate_t prev_st;
+  Idx src_idx, byte_idx, end_idx, remain_len;
+  size_t mbclen;
+#ifdef _LIBC
+  char buf[MB_LEN_MAX];
+  assert (MB_LEN_MAX >= pstr->mb_cur_max);
+#else
+  char buf[64];
+#endif
+
+  byte_idx = pstr->valid_len;
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+
+  /* The following optimization assumes that ASCII characters can be
+     mapped to wide characters with a simple cast.  */
+  if (! pstr->map_notascii && pstr->trans == NULL && !pstr->offsets_needed)
+    {
+      while (byte_idx < end_idx)
+        {
+          wchar_t wc;
+
+          if (isascii (pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx])
+              && mbsinit (&pstr->cur_state))
+            {
+              /* In case of a singlebyte character.  */
+              pstr->mbs[byte_idx]
+                = toupper (pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx]);
+              /* The next step uses the assumption that wchar_t is encoded
+                 ASCII-safe: all ASCII values can be converted like this.  */
+              pstr->wcs[byte_idx] = (wchar_t) pstr->mbs[byte_idx];
+              ++byte_idx;
+              continue;
+            }
+
+          remain_len = end_idx - byte_idx;
+          prev_st = pstr->cur_state;
+          mbclen = mbrtowc (&wc,
+                            ((const char *) pstr->raw_mbs + pstr->raw_mbs_idx
+                             + byte_idx), remain_len, &pstr->cur_state);
+          if (BE (mbclen < (size_t) -2, 1))
+            {
+              wchar_t wcu = wc;
+              if (iswlower (wc))
+                {
+                  size_t mbcdlen;
+
+                  wcu = towupper (wc);
+                  mbcdlen = wcrtomb (buf, wcu, &prev_st);
+                  if (BE (mbclen == mbcdlen, 1))
+                    memcpy (pstr->mbs + byte_idx, buf, mbclen);
+                  else
+                    {
+                      src_idx = byte_idx;
+                      goto offsets_needed;
+                    }
+                }
+              else
+                memcpy (pstr->mbs + byte_idx,
+                        pstr->raw_mbs + pstr->raw_mbs_idx + byte_idx, mbclen);
+              pstr->wcs[byte_idx++] = wcu;
+              /* Write paddings.  */
+              for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
+                pstr->wcs[byte_idx++] = WEOF;
+            }
+          else if (mbclen == (size_t) -1 || mbclen == 0)
+            {
+              /* It is an invalid character or '\0'.  Just use the byte.  */
+              int ch = pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
+              pstr->mbs[byte_idx] = ch;
+              /* And also cast it to wide char.  */
+              pstr->wcs[byte_idx++] = (wchar_t) ch;
+              if (BE (mbclen == (size_t) -1, 0))
+                pstr->cur_state = prev_st;
+            }
+          else
+            {
+              /* The buffer doesn't have enough space, finish to build.  */
+              pstr->cur_state = prev_st;
+              break;
+            }
+        }
+      pstr->valid_len = byte_idx;
+      pstr->valid_raw_len = byte_idx;
+      return REG_NOERROR;
+    }
+  else
+    for (src_idx = pstr->valid_raw_len; byte_idx < end_idx;)
+      {
+        wchar_t wc;
+        const char *p;
+      offsets_needed:
+        remain_len = end_idx - byte_idx;
+        prev_st = pstr->cur_state;
+        if (BE (pstr->trans != NULL, 0))
+          {
+            int i, ch;
+
+            for (i = 0; i < pstr->mb_cur_max && i < remain_len; ++i)
+              {
+                ch = pstr->raw_mbs [pstr->raw_mbs_idx + src_idx + i];
+                buf[i] = pstr->trans[ch];
+              }
+            p = (const char *) buf;
+          }
+        else
+          p = (const char *) pstr->raw_mbs + pstr->raw_mbs_idx + src_idx;
+        mbclen = mbrtowc (&wc, p, remain_len, &pstr->cur_state);
+        if (BE (mbclen < (size_t) -2, 1))
+          {
+            wchar_t wcu = wc;
+            if (iswlower (wc))
+              {
+                size_t mbcdlen;
+
+                wcu = towupper (wc);
+                mbcdlen = wcrtomb ((char *) buf, wcu, &prev_st);
+                if (BE (mbclen == mbcdlen, 1))
+                  memcpy (pstr->mbs + byte_idx, buf, mbclen);
+                else if (mbcdlen != (size_t) -1)
+                  {
+                    size_t i;
+
+                    if (byte_idx + mbcdlen > pstr->bufs_len)
+                      {
+                        pstr->cur_state = prev_st;
+                        break;
+                      }
+
+                    if (pstr->offsets == NULL)
+                      {
+                        pstr->offsets = re_malloc (Idx, pstr->bufs_len);
+
+                        if (pstr->offsets == NULL)
+                          return REG_ESPACE;
+                      }
+                    if (!pstr->offsets_needed)
+                      {
+                        for (i = 0; i < (size_t) byte_idx; ++i)
+                          pstr->offsets[i] = i;
+                        pstr->offsets_needed = 1;
+                      }
+
+                    memcpy (pstr->mbs + byte_idx, buf, mbcdlen);
+                    pstr->wcs[byte_idx] = wcu;
+                    pstr->offsets[byte_idx] = src_idx;
+                    for (i = 1; i < mbcdlen; ++i)
+                      {
+                        pstr->offsets[byte_idx + i]
+                          = src_idx + (i < mbclen ? i : mbclen - 1);
+                        pstr->wcs[byte_idx + i] = WEOF;
+                      }
+                    pstr->len += mbcdlen - mbclen;
+                    if (pstr->raw_stop > src_idx)
+                      pstr->stop += mbcdlen - mbclen;
+                    end_idx = (pstr->bufs_len > pstr->len)
+                              ? pstr->len : pstr->bufs_len;
+                    byte_idx += mbcdlen;
+                    src_idx += mbclen;
+                    continue;
+                  }
+                else
+                  memcpy (pstr->mbs + byte_idx, p, mbclen);
+              }
+            else
+              memcpy (pstr->mbs + byte_idx, p, mbclen);
+
+            if (BE (pstr->offsets_needed != 0, 0))
+              {
+                size_t i;
+                for (i = 0; i < mbclen; ++i)
+                  pstr->offsets[byte_idx + i] = src_idx + i;
+              }
+            src_idx += mbclen;
+
+            pstr->wcs[byte_idx++] = wcu;
+            /* Write paddings.  */
+            for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
+              pstr->wcs[byte_idx++] = WEOF;
+          }
+        else if (mbclen == (size_t) -1 || mbclen == 0)
+          {
+            /* It is an invalid character or '\0'.  Just use the byte.  */
+            int ch = pstr->raw_mbs[pstr->raw_mbs_idx + src_idx];
+
+            if (BE (pstr->trans != NULL, 0))
+              ch = pstr->trans [ch];
+            pstr->mbs[byte_idx] = ch;
+
+            if (BE (pstr->offsets_needed != 0, 0))
+              pstr->offsets[byte_idx] = src_idx;
+            ++src_idx;
+
+            /* And also cast it to wide char.  */
+            pstr->wcs[byte_idx++] = (wchar_t) ch;
+            if (BE (mbclen == (size_t) -1, 0))
+              pstr->cur_state = prev_st;
+          }
+        else
+          {
+            /* The buffer doesn't have enough space, finish to build.  */
+            pstr->cur_state = prev_st;
+            break;
+          }
+      }
+  pstr->valid_len = byte_idx;
+  pstr->valid_raw_len = src_idx;
+  return REG_NOERROR;
+}
+
+/* Skip characters until the index becomes greater than NEW_RAW_IDX.
+   Return the index.  */
+
+static Idx
+internal_function
+re_string_skip_chars (re_string_t *pstr, Idx new_raw_idx, wint_t *last_wc)
+{
+  mbstate_t prev_st;
+  Idx rawbuf_idx;
+  size_t mbclen;
+  wint_t wc = WEOF;
+
+  /* Skip the characters which are not necessary to check.  */
+  for (rawbuf_idx = pstr->raw_mbs_idx + pstr->valid_raw_len;
+       rawbuf_idx < new_raw_idx;)
+    {
+      wchar_t wc2;
+      Idx remain_len;
+      remain_len = pstr->len - rawbuf_idx;
+      prev_st = pstr->cur_state;
+      mbclen = mbrtowc (&wc2, (const char *) pstr->raw_mbs + rawbuf_idx,
+                        remain_len, &pstr->cur_state);
+      if (BE (mbclen == (size_t) -2 || mbclen == (size_t) -1 || mbclen == 0, 0))
+        {
+          /* We treat these cases as a single byte character.  */
+          if (mbclen == 0 || remain_len == 0)
+            wc = L'\0';
+          else
+            wc = *(unsigned char *) (pstr->raw_mbs + rawbuf_idx);
+          mbclen = 1;
+          pstr->cur_state = prev_st;
+        }
+      else
+        wc = wc2;
+      /* Then proceed the next character.  */
+      rawbuf_idx += mbclen;
+    }
+  *last_wc = wc;
+  return rawbuf_idx;
+}
+#endif /* RE_ENABLE_I18N  */
+
+/* Build the buffer PSTR->MBS, and apply the translation if we need.
+   This function is used in case of REG_ICASE.  */
+
+static void
+internal_function
+build_upper_buffer (re_string_t *pstr)
+{
+  Idx char_idx, end_idx;
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+
+  for (char_idx = pstr->valid_len; char_idx < end_idx; ++char_idx)
+    {
+      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + char_idx];
+      if (BE (pstr->trans != NULL, 0))
+        ch = pstr->trans[ch];
+      if (islower (ch))
+        pstr->mbs[char_idx] = toupper (ch);
+      else
+        pstr->mbs[char_idx] = ch;
+    }
+  pstr->valid_len = char_idx;
+  pstr->valid_raw_len = char_idx;
+}
+
+/* Apply TRANS to the buffer in PSTR.  */
+
+static void
+internal_function
+re_string_translate_buffer (re_string_t *pstr)
+{
+  Idx buf_idx, end_idx;
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+
+  for (buf_idx = pstr->valid_len; buf_idx < end_idx; ++buf_idx)
+    {
+      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + buf_idx];
+      pstr->mbs[buf_idx] = pstr->trans[ch];
+    }
+
+  pstr->valid_len = buf_idx;
+  pstr->valid_raw_len = buf_idx;
+}
+
+/* This function re-construct the buffers.
+   Concretely, convert to wide character in case of pstr->mb_cur_max > 1,
+   convert to upper case in case of REG_ICASE, apply translation.  */
+
+static reg_errcode_t
+internal_function
+re_string_reconstruct (re_string_t *pstr, Idx idx, int eflags)
+{
+  Idx offset;
+
+  if (BE (pstr->raw_mbs_idx <= idx, 0))
+    offset = idx - pstr->raw_mbs_idx;
+  else
+    {
+      /* Reset buffer.  */
+#ifdef RE_ENABLE_I18N
+      if (pstr->mb_cur_max > 1)
+        memset (&pstr->cur_state, '\0', sizeof (mbstate_t));
+#endif /* RE_ENABLE_I18N */
+      pstr->len = pstr->raw_len;
+      pstr->stop = pstr->raw_stop;
+      pstr->valid_len = 0;
+      pstr->raw_mbs_idx = 0;
+      pstr->valid_raw_len = 0;
+      pstr->offsets_needed = 0;
+      pstr->tip_context = ((eflags & REG_NOTBOL) ? CONTEXT_BEGBUF
+                           : CONTEXT_NEWLINE | CONTEXT_BEGBUF);
+      if (!pstr->mbs_allocated)
+        pstr->mbs = (unsigned char *) pstr->raw_mbs;
+      offset = idx;
+    }
+
+  if (BE (offset != 0, 1))
+    {
+      /* Should the already checked characters be kept?  */
+      if (BE (offset < pstr->valid_raw_len, 1))
+        {
+          /* Yes, move them to the front of the buffer.  */
+#ifdef RE_ENABLE_I18N
+          if (BE (pstr->offsets_needed, 0))
+            {
+              Idx low = 0, high = pstr->valid_len, mid;
+              do
+                {
+                  mid = (high + low) / 2;
+                  if (pstr->offsets[mid] > offset)
+                    high = mid;
+                  else if (pstr->offsets[mid] < offset)
+                    low = mid + 1;
+                  else
+                    break;
+                }
+              while (low < high);
+              if (pstr->offsets[mid] < offset)
+                ++mid;
+              pstr->tip_context = re_string_context_at (pstr, mid - 1,
+                                                        eflags);
+              /* This can be quite complicated, so handle specially
+                 only the common and easy case where the character with
+                 different length representation of lower and upper
+                 case is present at or after offset.  */
+              if (pstr->valid_len > offset
+                  && mid == offset && pstr->offsets[mid] == offset)
+                {
+                  memmove (pstr->wcs, pstr->wcs + offset,
+                           (pstr->valid_len - offset) * sizeof (wint_t));
+                  memmove (pstr->mbs, pstr->mbs + offset, pstr->valid_len - offset);
+                  pstr->valid_len -= offset;
+                  pstr->valid_raw_len -= offset;
+                  for (low = 0; low < pstr->valid_len; low++)
+                    pstr->offsets[low] = pstr->offsets[low + offset] - offset;
+                }
+              else
+                {
+                  /* Otherwise, just find out how long the partial multibyte
+                     character at offset is and fill it with WEOF/255.  */
+                  pstr->len = pstr->raw_len - idx + offset;
+                  pstr->stop = pstr->raw_stop - idx + offset;
+                  pstr->offsets_needed = 0;
+                  while (mid > 0 && pstr->offsets[mid - 1] == offset)
+                    --mid;
+                  while (mid < pstr->valid_len)
+                    if (pstr->wcs[mid] != WEOF)
+                      break;
+                    else
+                      ++mid;
+                  if (mid == pstr->valid_len)
+                    pstr->valid_len = 0;
+                  else
+                    {
+                      pstr->valid_len = pstr->offsets[mid] - offset;
+                      if (pstr->valid_len)
+                        {
+                          for (low = 0; low < pstr->valid_len; ++low)
+                            pstr->wcs[low] = WEOF;
+                          memset (pstr->mbs, 255, pstr->valid_len);
+                        }
+                    }
+                  pstr->valid_raw_len = pstr->valid_len;
+                }
+            }
+          else
+#endif
+            {
+              pstr->tip_context = re_string_context_at (pstr, offset - 1,
+                                                        eflags);
+#ifdef RE_ENABLE_I18N
+              if (pstr->mb_cur_max > 1)
+                memmove (pstr->wcs, pstr->wcs + offset,
+                         (pstr->valid_len - offset) * sizeof (wint_t));
+#endif /* RE_ENABLE_I18N */
+              if (BE (pstr->mbs_allocated, 0))
+                memmove (pstr->mbs, pstr->mbs + offset,
+                         pstr->valid_len - offset);
+              pstr->valid_len -= offset;
+              pstr->valid_raw_len -= offset;
+#if DEBUG
+              assert (pstr->valid_len > 0);
+#endif
+            }
+        }
+      else
+        {
+          /* No, skip all characters until IDX.  */
+          Idx prev_valid_len = pstr->valid_len;
+
+#ifdef RE_ENABLE_I18N
+          if (BE (pstr->offsets_needed, 0))
+            {
+              pstr->len = pstr->raw_len - idx + offset;
+              pstr->stop = pstr->raw_stop - idx + offset;
+              pstr->offsets_needed = 0;
+            }
+#endif
+          pstr->valid_len = 0;
+#ifdef RE_ENABLE_I18N
+          if (pstr->mb_cur_max > 1)
+            {
+              Idx wcs_idx;
+              wint_t wc = WEOF;
+
+              if (pstr->is_utf8)
+                {
+                  const unsigned char *raw, *p, *q, *end;
+
+                  /* Special case UTF-8.  Multi-byte chars start with any
+                     byte other than 0x80 - 0xbf.  */
+                  raw = pstr->raw_mbs + pstr->raw_mbs_idx;
+                  end = raw + (offset - pstr->mb_cur_max);
+                  if (end < pstr->raw_mbs)
+                    end = pstr->raw_mbs;
+                  p = raw + offset - 1;
+#ifdef _LIBC
+                  /* We know the wchar_t encoding is UCS4, so for the simple
+                     case, ASCII characters, skip the conversion step.  */
+                  if (isascii (*p) && BE (pstr->trans == NULL, 1))
+                    {
+                      memset (&pstr->cur_state, '\0', sizeof (mbstate_t));
+                      /* pstr->valid_len = 0; */
+                      wc = (wchar_t) *p;
+                    }
+                  else
+#endif
+                    for (; p >= end; --p)
+                      if ((*p & 0xc0) != 0x80)
+                        {
+                          mbstate_t cur_state;
+                          wchar_t wc2;
+                          Idx mlen = raw + pstr->len - p;
+                          unsigned char buf[6];
+                          size_t mbclen;
+
+                          q = p;
+                          if (BE (pstr->trans != NULL, 0))
+                            {
+                              int i = mlen < 6 ? mlen : 6;
+                              while (--i >= 0)
+                                buf[i] = pstr->trans[p[i]];
+                              q = buf;
+                            }
+                          /* XXX Don't use mbrtowc, we know which conversion
+                             to use (UTF-8 -> UCS4).  */
+                          memset (&cur_state, 0, sizeof (cur_state));
+                          mbclen = mbrtowc (&wc2, (const char *) p, mlen,
+                                            &cur_state);
+                          if (raw + offset - p <= mbclen
+                              && mbclen < (size_t) -2)
+                            {
+                              memset (&pstr->cur_state, '\0',
+                                      sizeof (mbstate_t));
+                              pstr->valid_len = mbclen - (raw + offset - p);
+                              wc = wc2;
+                            }
+                          break;
+                        }
+                }
+
+              if (wc == WEOF)
+                pstr->valid_len = re_string_skip_chars (pstr, idx, &wc) - idx;
+              if (wc == WEOF)
+                pstr->tip_context
+                  = re_string_context_at (pstr, prev_valid_len - 1, eflags);
+              else
+                pstr->tip_context = ((BE (pstr->word_ops_used != 0, 0)
+                                      && IS_WIDE_WORD_CHAR (wc))
+                                     ? CONTEXT_WORD
+                                     : ((IS_WIDE_NEWLINE (wc)
+                                         && pstr->newline_anchor)
+                                        ? CONTEXT_NEWLINE : 0));
+              if (BE (pstr->valid_len, 0))
+                {
+                  for (wcs_idx = 0; wcs_idx < pstr->valid_len; ++wcs_idx)
+                    pstr->wcs[wcs_idx] = WEOF;
+                  if (pstr->mbs_allocated)
+                    memset (pstr->mbs, 255, pstr->valid_len);
+                }
+              pstr->valid_raw_len = pstr->valid_len;
+            }
+          else
+#endif /* RE_ENABLE_I18N */
+            {
+              int c = pstr->raw_mbs[pstr->raw_mbs_idx + offset - 1];
+              pstr->valid_raw_len = 0;
+              if (pstr->trans)
+                c = pstr->trans[c];
+              pstr->tip_context = (bitset_contain (pstr->word_char, c)
+                                   ? CONTEXT_WORD
+                                   : ((IS_NEWLINE (c) && pstr->newline_anchor)
+                                      ? CONTEXT_NEWLINE : 0));
+            }
+        }
+      if (!BE (pstr->mbs_allocated, 0))
+        pstr->mbs += offset;
+    }
+  pstr->raw_mbs_idx = idx;
+  pstr->len -= offset;
+  pstr->stop -= offset;
+
+  /* Then build the buffers.  */
+#ifdef RE_ENABLE_I18N
+  if (pstr->mb_cur_max > 1)
+    {
+      if (pstr->icase)
+        {
+          reg_errcode_t ret = build_wcs_upper_buffer (pstr);
+          if (BE (ret != REG_NOERROR, 0))
+            return ret;
+        }
+      else
+        build_wcs_buffer (pstr);
+    }
+  else
+#endif /* RE_ENABLE_I18N */
+    if (BE (pstr->mbs_allocated, 0))
+      {
+        if (pstr->icase)
+          build_upper_buffer (pstr);
+        else if (pstr->trans != NULL)
+          re_string_translate_buffer (pstr);
+      }
+    else
+      pstr->valid_len = pstr->len;
+
+  pstr->cur_idx = 0;
+  return REG_NOERROR;
+}
+
+static unsigned char
+internal_function __attribute ((pure))
+re_string_peek_byte_case (const re_string_t *pstr, Idx idx)
+{
+  int ch;
+  Idx off;
+
+  /* Handle the common (easiest) cases first.  */
+  if (BE (!pstr->mbs_allocated, 1))
+    return re_string_peek_byte (pstr, idx);
+
+#ifdef RE_ENABLE_I18N
+  if (pstr->mb_cur_max > 1
+      && ! re_string_is_single_byte_char (pstr, pstr->cur_idx + idx))
+    return re_string_peek_byte (pstr, idx);
+#endif
+
+  off = pstr->cur_idx + idx;
+#ifdef RE_ENABLE_I18N
+  if (pstr->offsets_needed)
+    off = pstr->offsets[off];
+#endif
+
+  ch = pstr->raw_mbs[pstr->raw_mbs_idx + off];
+
+#ifdef RE_ENABLE_I18N
+  /* Ensure that e.g. for tr_TR.UTF-8 BACKSLASH DOTLESS SMALL LETTER I
+     this function returns CAPITAL LETTER I instead of first byte of
+     DOTLESS SMALL LETTER I.  The latter would confuse the parser,
+     since peek_byte_case doesn't advance cur_idx in any way.  */
+  if (pstr->offsets_needed && !isascii (ch))
+    return re_string_peek_byte (pstr, idx);
+#endif
+
+  return ch;
+}
+
+static unsigned char
+internal_function __attribute ((pure))
+re_string_fetch_byte_case (re_string_t *pstr)
+{
+  if (BE (!pstr->mbs_allocated, 1))
+    return re_string_fetch_byte (pstr);
+
+#ifdef RE_ENABLE_I18N
+  if (pstr->offsets_needed)
+    {
+      Idx off;
+      int ch;
+
+      /* For tr_TR.UTF-8 [[:islower:]] there is
+         [[: CAPITAL LETTER I WITH DOT lower:]] in mbs.  Skip
+         in that case the whole multi-byte character and return
+         the original letter.  On the other side, with
+         [[: DOTLESS SMALL LETTER I return [[:I, as doing
+         anything else would complicate things too much.  */
+
+      if (!re_string_first_byte (pstr, pstr->cur_idx))
+        return re_string_fetch_byte (pstr);
+
+      off = pstr->offsets[pstr->cur_idx];
+      ch = pstr->raw_mbs[pstr->raw_mbs_idx + off];
+
+      if (! isascii (ch))
+        return re_string_fetch_byte (pstr);
+
+      re_string_skip_bytes (pstr,
+                            re_string_char_size_at (pstr, pstr->cur_idx));
+      return ch;
+    }
+#endif
+
+  return pstr->raw_mbs[pstr->raw_mbs_idx + pstr->cur_idx++];
+}
+
+static void
+internal_function
+re_string_destruct (re_string_t *pstr)
+{
+#ifdef RE_ENABLE_I18N
+  re_free (pstr->wcs);
+  re_free (pstr->offsets);
+#endif /* RE_ENABLE_I18N  */
+  if (pstr->mbs_allocated)
+    re_free (pstr->mbs);
+}
+
+/* Return the context at IDX in INPUT.  */
+
+static unsigned int
+internal_function
+re_string_context_at (const re_string_t *input, Idx idx, int eflags)
+{
+  int c;
+  if (BE (! REG_VALID_INDEX (idx), 0))
+    /* In this case, we use the value stored in input->tip_context,
+       since we can't know the character in input->mbs[-1] here.  */
+    return input->tip_context;
+  if (BE (idx == input->len, 0))
+    return ((eflags & REG_NOTEOL) ? CONTEXT_ENDBUF
+            : CONTEXT_NEWLINE | CONTEXT_ENDBUF);
+#ifdef RE_ENABLE_I18N
+  if (input->mb_cur_max > 1)
+    {
+      wint_t wc;
+      Idx wc_idx = idx;
+      while(input->wcs[wc_idx] == WEOF)
+        {
+#ifdef DEBUG
+          /* It must not happen.  */
+          assert (REG_VALID_INDEX (wc_idx));
+#endif
+          --wc_idx;
+          if (! REG_VALID_INDEX (wc_idx))
+            return input->tip_context;
+        }
+      wc = input->wcs[wc_idx];
+      if (BE (input->word_ops_used != 0, 0) && IS_WIDE_WORD_CHAR (wc))
+        return CONTEXT_WORD;
+      return (IS_WIDE_NEWLINE (wc) && input->newline_anchor
+              ? CONTEXT_NEWLINE : 0);
+    }
+  else
+#endif
+    {
+      c = re_string_byte_at (input, idx);
+      if (bitset_contain (input->word_char, c))
+        return CONTEXT_WORD;
+      return IS_NEWLINE (c) && input->newline_anchor ? CONTEXT_NEWLINE : 0;
+    }
+}
+
+/* Functions for set operation.  */
+
+static reg_errcode_t
+internal_function
+re_node_set_alloc (re_node_set *set, Idx size)
+{
+  set->alloc = size;
+  set->nelem = 0;
+  set->elems = re_malloc (Idx, size);
+  if (BE (set->elems == NULL, 0))
+    return REG_ESPACE;
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+internal_function
+re_node_set_init_1 (re_node_set *set, Idx elem)
+{
+  set->alloc = 1;
+  set->nelem = 1;
+  set->elems = re_malloc (Idx, 1);
+  if (BE (set->elems == NULL, 0))
+    {
+      set->alloc = set->nelem = 0;
+      return REG_ESPACE;
+    }
+  set->elems[0] = elem;
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+internal_function
+re_node_set_init_2 (re_node_set *set, Idx elem1, Idx elem2)
+{
+  set->alloc = 2;
+  set->elems = re_malloc (Idx, 2);
+  if (BE (set->elems == NULL, 0))
+    return REG_ESPACE;
+  if (elem1 == elem2)
+    {
+      set->nelem = 1;
+      set->elems[0] = elem1;
+    }
+  else
+    {
+      set->nelem = 2;
+      if (elem1 < elem2)
+        {
+          set->elems[0] = elem1;
+          set->elems[1] = elem2;
+        }
+      else
+        {
+          set->elems[0] = elem2;
+          set->elems[1] = elem1;
+        }
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+internal_function
+re_node_set_init_copy (re_node_set *dest, const re_node_set *src)
+{
+  dest->nelem = src->nelem;
+  if (src->nelem > 0)
+    {
+      dest->alloc = dest->nelem;
+      dest->elems = re_malloc (Idx, dest->alloc);
+      if (BE (dest->elems == NULL, 0))
+        {
+          dest->alloc = dest->nelem = 0;
+          return REG_ESPACE;
+        }
+      memcpy (dest->elems, src->elems, src->nelem * sizeof (Idx));
+    }
+  else
+    re_node_set_init_empty (dest);
+  return REG_NOERROR;
+}
+
+/* Calculate the intersection of the sets SRC1 and SRC2. And merge it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.
+   Note: We assume dest->elems is NULL, when dest->alloc is 0.  */
+
+static reg_errcode_t
+internal_function
+re_node_set_add_intersect (re_node_set *dest, const re_node_set *src1,
+                           const re_node_set *src2)
+{
+  Idx i1, i2, is, id, delta, sbase;
+  if (src1->nelem == 0 || src2->nelem == 0)
+    return REG_NOERROR;
+
+  /* We need dest->nelem + 2 * elems_in_intersection; this is a
+     conservative estimate.  */
+  if (src1->nelem + src2->nelem + dest->nelem > dest->alloc)
+    {
+      Idx new_alloc = src1->nelem + src2->nelem + dest->alloc;
+      Idx *new_elems = re_realloc (dest->elems, Idx, new_alloc);
+      if (BE (new_elems == NULL, 0))
+        return REG_ESPACE;
+      dest->elems = new_elems;
+      dest->alloc = new_alloc;
+    }
+
+  /* Find the items in the intersection of SRC1 and SRC2, and copy
+     into the top of DEST those that are not already in DEST itself.  */
+  sbase = dest->nelem + src1->nelem + src2->nelem;
+  i1 = src1->nelem - 1;
+  i2 = src2->nelem - 1;
+  id = dest->nelem - 1;
+  for (;;)
+    {
+      if (src1->elems[i1] == src2->elems[i2])
+        {
+          /* Try to find the item in DEST.  Maybe we could binary search?  */
+          while (REG_VALID_INDEX (id) && dest->elems[id] > src1->elems[i1])
+            --id;
+
+          if (! REG_VALID_INDEX (id) || dest->elems[id] != src1->elems[i1])
+            dest->elems[--sbase] = src1->elems[i1];
+
+          if (! REG_VALID_INDEX (--i1) || ! REG_VALID_INDEX (--i2))
+            break;
+        }
+
+      /* Lower the highest of the two items.  */
+      else if (src1->elems[i1] < src2->elems[i2])
+        {
+          if (! REG_VALID_INDEX (--i2))
+            break;
+        }
+      else
+        {
+          if (! REG_VALID_INDEX (--i1))
+            break;
+        }
+    }
+
+  id = dest->nelem - 1;
+  is = dest->nelem + src1->nelem + src2->nelem - 1;
+  delta = is - sbase + 1;
+
+  /* Now copy.  When DELTA becomes zero, the remaining
+     DEST elements are already in place; this is more or
+     less the same loop that is in re_node_set_merge.  */
+  dest->nelem += delta;
+  if (delta > 0 && REG_VALID_INDEX (id))
+    for (;;)
+      {
+        if (dest->elems[is] > dest->elems[id])
+          {
+            /* Copy from the top.  */
+            dest->elems[id + delta--] = dest->elems[is--];
+            if (delta == 0)
+              break;
+          }
+        else
+          {
+            /* Slide from the bottom.  */
+            dest->elems[id + delta] = dest->elems[id];
+            if (! REG_VALID_INDEX (--id))
+              break;
+          }
+      }
+
+  /* Copy remaining SRC elements.  */
+  memcpy (dest->elems, dest->elems + sbase, delta * sizeof (Idx));
+
+  return REG_NOERROR;
+}
+
+/* Calculate the union set of the sets SRC1 and SRC2. And store it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.  */
+
+static reg_errcode_t
+internal_function
+re_node_set_init_union (re_node_set *dest, const re_node_set *src1,
+                        const re_node_set *src2)
+{
+  Idx i1, i2, id;
+  if (src1 != NULL && src1->nelem > 0 && src2 != NULL && src2->nelem > 0)
+    {
+      dest->alloc = src1->nelem + src2->nelem;
+      dest->elems = re_malloc (Idx, dest->alloc);
+      if (BE (dest->elems == NULL, 0))
+        return REG_ESPACE;
+    }
+  else
+    {
+      if (src1 != NULL && src1->nelem > 0)
+        return re_node_set_init_copy (dest, src1);
+      else if (src2 != NULL && src2->nelem > 0)
+        return re_node_set_init_copy (dest, src2);
+      else
+        re_node_set_init_empty (dest);
+      return REG_NOERROR;
+    }
+  for (i1 = i2 = id = 0 ; i1 < src1->nelem && i2 < src2->nelem ;)
+    {
+      if (src1->elems[i1] > src2->elems[i2])
+        {
+          dest->elems[id++] = src2->elems[i2++];
+          continue;
+        }
+      if (src1->elems[i1] == src2->elems[i2])
+        ++i2;
+      dest->elems[id++] = src1->elems[i1++];
+    }
+  if (i1 < src1->nelem)
+    {
+      memcpy (dest->elems + id, src1->elems + i1,
+             (src1->nelem - i1) * sizeof (Idx));
+      id += src1->nelem - i1;
+    }
+  else if (i2 < src2->nelem)
+    {
+      memcpy (dest->elems + id, src2->elems + i2,
+             (src2->nelem - i2) * sizeof (Idx));
+      id += src2->nelem - i2;
+    }
+  dest->nelem = id;
+  return REG_NOERROR;
+}
+
+/* Calculate the union set of the sets DEST and SRC. And store it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.  */
+
+static reg_errcode_t
+internal_function
+re_node_set_merge (re_node_set *dest, const re_node_set *src)
+{
+  Idx is, id, sbase, delta;
+  if (src == NULL || src->nelem == 0)
+    return REG_NOERROR;
+  if (dest->alloc < 2 * src->nelem + dest->nelem)
+    {
+      Idx new_alloc = 2 * (src->nelem + dest->alloc);
+      Idx *new_buffer = re_realloc (dest->elems, Idx, new_alloc);
+      if (BE (new_buffer == NULL, 0))
+        return REG_ESPACE;
+      dest->elems = new_buffer;
+      dest->alloc = new_alloc;
+    }
+
+  if (BE (dest->nelem == 0, 0))
+    {
+      dest->nelem = src->nelem;
+      memcpy (dest->elems, src->elems, src->nelem * sizeof (Idx));
+      return REG_NOERROR;
+    }
+
+  /* Copy into the top of DEST the items of SRC that are not
+     found in DEST.  Maybe we could binary search in DEST?  */
+  for (sbase = dest->nelem + 2 * src->nelem,
+       is = src->nelem - 1, id = dest->nelem - 1;
+       REG_VALID_INDEX (is) && REG_VALID_INDEX (id); )
+    {
+      if (dest->elems[id] == src->elems[is])
+        is--, id--;
+      else if (dest->elems[id] < src->elems[is])
+        dest->elems[--sbase] = src->elems[is--];
+      else /* if (dest->elems[id] > src->elems[is]) */
+        --id;
+    }
+
+  if (REG_VALID_INDEX (is))
+    {
+      /* If DEST is exhausted, the remaining items of SRC must be unique.  */
+      sbase -= is + 1;
+      memcpy (dest->elems + sbase, src->elems, (is + 1) * sizeof (Idx));
+    }
+
+  id = dest->nelem - 1;
+  is = dest->nelem + 2 * src->nelem - 1;
+  delta = is - sbase + 1;
+  if (delta == 0)
+    return REG_NOERROR;
+
+  /* Now copy.  When DELTA becomes zero, the remaining
+     DEST elements are already in place.  */
+  dest->nelem += delta;
+  for (;;)
+    {
+      if (dest->elems[is] > dest->elems[id])
+        {
+          /* Copy from the top.  */
+          dest->elems[id + delta--] = dest->elems[is--];
+          if (delta == 0)
+            break;
+        }
+      else
+        {
+          /* Slide from the bottom.  */
+          dest->elems[id + delta] = dest->elems[id];
+          if (! REG_VALID_INDEX (--id))
+            {
+              /* Copy remaining SRC elements.  */
+              memcpy (dest->elems, dest->elems + sbase,
+                      delta * sizeof (Idx));
+              break;
+            }
+        }
+    }
+
+  return REG_NOERROR;
+}
+
+/* Insert the new element ELEM to the re_node_set* SET.
+   SET should not already have ELEM.
+   Return true if successful.  */
+
+static bool
+internal_function
+re_node_set_insert (re_node_set *set, Idx elem)
+{
+  Idx idx;
+  /* In case the set is empty.  */
+  if (set->alloc == 0)
+    return BE (re_node_set_init_1 (set, elem) == REG_NOERROR, 1);
+
+  if (BE (set->nelem, 0) == 0)
+    {
+      /* We already guaranteed above that set->alloc != 0.  */
+      set->elems[0] = elem;
+      ++set->nelem;
+      return true;
+    }
+
+  /* Realloc if we need.  */
+  if (set->alloc == set->nelem)
+    {
+      Idx *new_elems;
+      set->alloc = set->alloc * 2;
+      new_elems = re_realloc (set->elems, Idx, set->alloc);
+      if (BE (new_elems == NULL, 0))
+        return false;
+      set->elems = new_elems;
+    }
+
+  /* Move the elements which follows the new element.  Test the
+     first element separately to skip a check in the inner loop.  */
+  if (elem < set->elems[0])
+    {
+      idx = 0;
+      for (idx = set->nelem; idx > 0; idx--)
+        set->elems[idx] = set->elems[idx - 1];
+    }
+  else
+    {
+      for (idx = set->nelem; set->elems[idx - 1] > elem; idx--)
+        set->elems[idx] = set->elems[idx - 1];
+    }
+
+  /* Insert the new element.  */
+  set->elems[idx] = elem;
+  ++set->nelem;
+  return true;
+}
+
+/* Insert the new element ELEM to the re_node_set* SET.
+   SET should not already have any element greater than or equal to ELEM.
+   Return true if successful.  */
+
+static bool
+internal_function
+re_node_set_insert_last (re_node_set *set, Idx elem)
+{
+  /* Realloc if we need.  */
+  if (set->alloc == set->nelem)
+    {
+      Idx *new_elems;
+      set->alloc = (set->alloc + 1) * 2;
+      new_elems = re_realloc (set->elems, Idx, set->alloc);
+      if (BE (new_elems == NULL, 0))
+        return false;
+      set->elems = new_elems;
+    }
+
+  /* Insert the new element.  */
+  set->elems[set->nelem++] = elem;
+  return true;
+}
+
+/* Compare two node sets SET1 and SET2.
+   Return true if SET1 and SET2 are equivalent.  */
+
+static bool
+internal_function __attribute ((pure))
+re_node_set_compare (const re_node_set *set1, const re_node_set *set2)
+{
+  Idx i;
+  if (set1 == NULL || set2 == NULL || set1->nelem != set2->nelem)
+    return false;
+  for (i = set1->nelem ; REG_VALID_INDEX (--i) ; )
+    if (set1->elems[i] != set2->elems[i])
+      return false;
+  return true;
+}
+
+/* Return (idx + 1) if SET contains the element ELEM, return 0 otherwise.  */
+
+static Idx
+internal_function __attribute ((pure))
+re_node_set_contains (const re_node_set *set, Idx elem)
+{
+  __re_size_t idx, right, mid;
+  if (! REG_VALID_NONZERO_INDEX (set->nelem))
+    return 0;
+
+  /* Binary search the element.  */
+  idx = 0;
+  right = set->nelem - 1;
+  while (idx < right)
+    {
+      mid = (idx + right) / 2;
+      if (set->elems[mid] < elem)
+        idx = mid + 1;
+      else
+        right = mid;
+    }
+  return set->elems[idx] == elem ? idx + 1 : 0;
+}
+
+static void
+internal_function
+re_node_set_remove_at (re_node_set *set, Idx idx)
+{
+  if (idx < 0 || idx >= set->nelem)
+    return;
+  --set->nelem;
+  for (; idx < set->nelem; idx++)
+    set->elems[idx] = set->elems[idx + 1];
+}
+
+
+/* Add the token TOKEN to dfa->nodes, and return the index of the token.
+   Or return REG_MISSING if an error occurred.  */
+
+static Idx
+internal_function
+re_dfa_add_node (re_dfa_t *dfa, re_token_t token)
+{
+  if (BE (dfa->nodes_len >= dfa->nodes_alloc, 0))
+    {
+      size_t new_nodes_alloc = dfa->nodes_alloc * 2;
+      Idx *new_nexts, *new_indices;
+      re_node_set *new_edests, *new_eclosures;
+      re_token_t *new_nodes;
+      size_t max_object_size =
+        MAX (sizeof (re_token_t),
+             MAX (sizeof (re_node_set),
+                  sizeof (Idx)));
+
+      /* Avoid overflows.  */
+      if (BE (SIZE_MAX / 2 / max_object_size < dfa->nodes_alloc, 0))
+        return REG_MISSING;
+
+      new_nodes = re_realloc (dfa->nodes, re_token_t, new_nodes_alloc);
+      if (BE (new_nodes == NULL, 0))
+        return REG_MISSING;
+      dfa->nodes = new_nodes;
+      new_nexts = re_realloc (dfa->nexts, Idx, new_nodes_alloc);
+      new_indices = re_realloc (dfa->org_indices, Idx, new_nodes_alloc);
+      new_edests = re_realloc (dfa->edests, re_node_set, new_nodes_alloc);
+      new_eclosures = re_realloc (dfa->eclosures, re_node_set, new_nodes_alloc);
+      if (BE (new_nexts == NULL || new_indices == NULL
+              || new_edests == NULL || new_eclosures == NULL, 0))
+        return REG_MISSING;
+      dfa->nexts = new_nexts;
+      dfa->org_indices = new_indices;
+      dfa->edests = new_edests;
+      dfa->eclosures = new_eclosures;
+      dfa->nodes_alloc = new_nodes_alloc;
+    }
+  dfa->nodes[dfa->nodes_len] = token;
+  dfa->nodes[dfa->nodes_len].constraint = 0;
+#ifdef RE_ENABLE_I18N
+  {
+  int type = token.type;
+  dfa->nodes[dfa->nodes_len].accept_mb =
+    (type == OP_PERIOD && dfa->mb_cur_max > 1) || type == COMPLEX_BRACKET;
+  }
+#endif
+  dfa->nexts[dfa->nodes_len] = REG_MISSING;
+  re_node_set_init_empty (dfa->edests + dfa->nodes_len);
+  re_node_set_init_empty (dfa->eclosures + dfa->nodes_len);
+  return dfa->nodes_len++;
+}
+
+static inline re_hashval_t
+internal_function
+calc_state_hash (const re_node_set *nodes, unsigned int context)
+{
+  re_hashval_t hash = nodes->nelem + context;
+  Idx i;
+  for (i = 0 ; i < nodes->nelem ; i++)
+    hash += nodes->elems[i];
+  return hash;
+}
+
+/* Search for the state whose node_set is equivalent to NODES.
+   Return the pointer to the state, if we found it in the DFA.
+   Otherwise create the new one and return it.  In case of an error
+   return NULL and set the error code in ERR.
+   Note: - We assume NULL as the invalid state, then it is possible that
+           return value is NULL and ERR is REG_NOERROR.
+         - We never return non-NULL value in case of any errors, it is for
+           optimization.  */
+
+static re_dfastate_t *
+internal_function
+re_acquire_state (reg_errcode_t *err, const re_dfa_t *dfa,
+                  const re_node_set *nodes)
+{
+  re_hashval_t hash;
+  re_dfastate_t *new_state;
+  struct re_state_table_entry *spot;
+  Idx i;
+#ifdef lint
+  /* Suppress bogus uninitialized-variable warnings.  */
+  *err = REG_NOERROR;
+#endif
+  if (BE (nodes->nelem == 0, 0))
+    {
+      *err = REG_NOERROR;
+      return NULL;
+    }
+  hash = calc_state_hash (nodes, 0);
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+
+  for (i = 0 ; i < spot->num ; i++)
+    {
+      re_dfastate_t *state = spot->array[i];
+      if (hash != state->hash)
+        continue;
+      if (re_node_set_compare (&state->nodes, nodes))
+        return state;
+    }
+
+  /* There are no appropriate state in the dfa, create the new one.  */
+  new_state = create_ci_newstate (dfa, nodes, hash);
+  if (BE (new_state == NULL, 0))
+    *err = REG_ESPACE;
+
+  return new_state;
+}
+
+/* Search for the state whose node_set is equivalent to NODES and
+   whose context is equivalent to CONTEXT.
+   Return the pointer to the state, if we found it in the DFA.
+   Otherwise create the new one and return it.  In case of an error
+   return NULL and set the error code in ERR.
+   Note: - We assume NULL as the invalid state, then it is possible that
+           return value is NULL and ERR is REG_NOERROR.
+         - We never return non-NULL value in case of any errors, it is for
+           optimization.  */
+
+static re_dfastate_t *
+internal_function
+re_acquire_state_context (reg_errcode_t *err, const re_dfa_t *dfa,
+                          const re_node_set *nodes, unsigned int context)
+{
+  re_hashval_t hash;
+  re_dfastate_t *new_state;
+  struct re_state_table_entry *spot;
+  Idx i;
+#ifdef lint
+  /* Suppress bogus uninitialized-variable warnings.  */
+  *err = REG_NOERROR;
+#endif
+  if (nodes->nelem == 0)
+    {
+      *err = REG_NOERROR;
+      return NULL;
+    }
+  hash = calc_state_hash (nodes, context);
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+
+  for (i = 0 ; i < spot->num ; i++)
+    {
+      re_dfastate_t *state = spot->array[i];
+      if (state->hash == hash
+          && state->context == context
+          && re_node_set_compare (state->entrance_nodes, nodes))
+        return state;
+    }
+  /* There are no appropriate state in `dfa', create the new one.  */
+  new_state = create_cd_newstate (dfa, nodes, context, hash);
+  if (BE (new_state == NULL, 0))
+    *err = REG_ESPACE;
+
+  return new_state;
+}
+
+/* Finish initialization of the new state NEWSTATE, and using its hash value
+   HASH put in the appropriate bucket of DFA's state table.  Return value
+   indicates the error code if failed.  */
+
+static reg_errcode_t
+register_state (const re_dfa_t *dfa, re_dfastate_t *newstate,
+                re_hashval_t hash)
+{
+  struct re_state_table_entry *spot;
+  reg_errcode_t err;
+  Idx i;
+
+  newstate->hash = hash;
+  err = re_node_set_alloc (&newstate->non_eps_nodes, newstate->nodes.nelem);
+  if (BE (err != REG_NOERROR, 0))
+    return REG_ESPACE;
+  for (i = 0; i < newstate->nodes.nelem; i++)
+    {
+      Idx elem = newstate->nodes.elems[i];
+      if (!IS_EPSILON_NODE (dfa->nodes[elem].type))
+        if (BE (! re_node_set_insert_last (&newstate->non_eps_nodes, elem), 0))
+          return REG_ESPACE;
+    }
+
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+  if (BE (spot->alloc <= spot->num, 0))
+    {
+      Idx new_alloc = 2 * spot->num + 2;
+      re_dfastate_t **new_array = re_realloc (spot->array, re_dfastate_t *,
+                                              new_alloc);
+      if (BE (new_array == NULL, 0))
+        return REG_ESPACE;
+      spot->array = new_array;
+      spot->alloc = new_alloc;
+    }
+  spot->array[spot->num++] = newstate;
+  return REG_NOERROR;
+}
+
+static void
+free_state (re_dfastate_t *state)
+{
+  re_node_set_free (&state->non_eps_nodes);
+  re_node_set_free (&state->inveclosure);
+  if (state->entrance_nodes != &state->nodes)
+    {
+      re_node_set_free (state->entrance_nodes);
+      re_free (state->entrance_nodes);
+    }
+  re_node_set_free (&state->nodes);
+  re_free (state->word_trtable);
+  re_free (state->trtable);
+  re_free (state);
+}
+
+/* Create the new state which is independ of contexts.
+   Return the new state if succeeded, otherwise return NULL.  */
+
+static re_dfastate_t *
+internal_function
+create_ci_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
+                    re_hashval_t hash)
+{
+  Idx i;
+  reg_errcode_t err;
+  re_dfastate_t *newstate;
+
+  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
+  if (BE (newstate == NULL, 0))
+    return NULL;
+  err = re_node_set_init_copy (&newstate->nodes, nodes);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      re_free (newstate);
+      return NULL;
+    }
+
+  newstate->entrance_nodes = &newstate->nodes;
+  for (i = 0 ; i < nodes->nelem ; i++)
+    {
+      re_token_t *node = dfa->nodes + nodes->elems[i];
+      re_token_type_t type = node->type;
+      if (type == CHARACTER && !node->constraint)
+        continue;
+#ifdef RE_ENABLE_I18N
+      newstate->accept_mb |= node->accept_mb;
+#endif /* RE_ENABLE_I18N */
+
+      /* If the state has the halt node, the state is a halt state.  */
+      if (type == END_OF_RE)
+        newstate->halt = 1;
+      else if (type == OP_BACK_REF)
+        newstate->has_backref = 1;
+      else if (type == ANCHOR || node->constraint)
+        newstate->has_constraint = 1;
+    }
+  err = register_state (dfa, newstate, hash);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      free_state (newstate);
+      newstate = NULL;
+    }
+  return newstate;
+}
+
+/* Create the new state which is depend on the context CONTEXT.
+   Return the new state if succeeded, otherwise return NULL.  */
+
+static re_dfastate_t *
+internal_function
+create_cd_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
+                    unsigned int context, re_hashval_t hash)
+{
+  Idx i, nctx_nodes = 0;
+  reg_errcode_t err;
+  re_dfastate_t *newstate;
+
+  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
+  if (BE (newstate == NULL, 0))
+    return NULL;
+  err = re_node_set_init_copy (&newstate->nodes, nodes);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      re_free (newstate);
+      return NULL;
+    }
+
+  newstate->context = context;
+  newstate->entrance_nodes = &newstate->nodes;
+
+  for (i = 0 ; i < nodes->nelem ; i++)
+    {
+      unsigned int constraint = 0;
+      re_token_t *node = dfa->nodes + nodes->elems[i];
+      re_token_type_t type = node->type;
+      if (node->constraint)
+        constraint = node->constraint;
+
+      if (type == CHARACTER && !constraint)
+        continue;
+#ifdef RE_ENABLE_I18N
+      newstate->accept_mb |= node->accept_mb;
+#endif /* RE_ENABLE_I18N */
+
+      /* If the state has the halt node, the state is a halt state.  */
+      if (type == END_OF_RE)
+        newstate->halt = 1;
+      else if (type == OP_BACK_REF)
+        newstate->has_backref = 1;
+      else if (type == ANCHOR)
+        constraint = node->opr.ctx_type;
+
+      if (constraint)
+        {
+          if (newstate->entrance_nodes == &newstate->nodes)
+            {
+              newstate->entrance_nodes = re_malloc (re_node_set, 1);
+              if (BE (newstate->entrance_nodes == NULL, 0))
+                {
+                  free_state (newstate);
+                  return NULL;
+                }
+              re_node_set_init_copy (newstate->entrance_nodes, nodes);
+              nctx_nodes = 0;
+              newstate->has_constraint = 1;
+            }
+
+          if (NOT_SATISFY_PREV_CONSTRAINT (constraint,context))
+            {
+              re_node_set_remove_at (&newstate->nodes, i - nctx_nodes);
+              ++nctx_nodes;
+            }
+        }
+    }
+  err = register_state (dfa, newstate, hash);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      free_state (newstate);
+      newstate = NULL;
+    }
+  return  newstate;
+}