stringprep.c

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/* stringprep.c --- Core stringprep implementation.
 * Copyright (C) 2002, 2003, 2004  Simon Josefsson
 *
 * This file is part of GNU Libidn.
 *
 * GNU Libidn is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * GNU Libidn 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with GNU Libidn; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 *
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdlib.h>
#include <string.h>

#include "stringprep.h"

static ssize_t
stringprep_find_character_in_table (uint32_t ucs4,
                                    const Stringprep_table_element * table)
{
  ssize_t i;

  /* This is where typical uses of Libidn spends very close to all CPU
     time and causes most cache misses.  One could easily do a binary
     search instead.  Before rewriting this, I want hard evidence this
     slowness is at all relevant in typical applications.  (I don't
     dispute optimization may improve matters significantly, I'm
     mostly interested in having someone give real-world benchmark on
     the impact of libidn.) */

  for (i = 0; table[i].start || table[i].end; i++)
    if (ucs4 >= table[i].start &&
        ucs4 <= (table[i].end ? table[i].end : table[i].start))
      return i;

  return -1;
}

static ssize_t
stringprep_find_string_in_table (uint32_t * ucs4,
                                 size_t ucs4len,
                                 size_t * tablepos,
                                 const Stringprep_table_element * table)
{
  size_t j;
  ssize_t pos;

  for (j = 0; j < ucs4len; j++)
    if ((pos = stringprep_find_character_in_table (ucs4[j], table)) != -1)
      {
        if (tablepos)
          *tablepos = pos;
        return j;
      }

  return -1;
}

static int
stringprep_apply_table_to_string (uint32_t * ucs4,
                                  size_t * ucs4len,
                                  size_t maxucs4len,
                                  const Stringprep_table_element * table)
{
  ssize_t pos;
  size_t i, maplen;

  while ((pos = stringprep_find_string_in_table (ucs4, *ucs4len,
                                                 &i, table)) != -1)
    {
      for (maplen = STRINGPREP_MAX_MAP_CHARS;
           maplen > 0 && table[i].map[maplen - 1] == 0; maplen--)
        ;

      if (*ucs4len - 1 + maplen >= maxucs4len)
        return STRINGPREP_TOO_SMALL_BUFFER;

      memmove (&ucs4[pos + maplen], &ucs4[pos + 1],
               sizeof (uint32_t) * (*ucs4len - pos - 1));
      memcpy (&ucs4[pos], table[i].map, sizeof (uint32_t) * maplen);
      *ucs4len = *ucs4len - 1 + maplen;
    }

  return STRINGPREP_OK;
}

#define INVERTED(x) ((x) & ((~0UL) >> 1))
#define UNAPPLICAPLEFLAGS(flags, profileflags) \
  ((!INVERTED(profileflags) && !(profileflags & flags) && profileflags) || \
   ( INVERTED(profileflags) && (profileflags & flags)))

int
stringprep_4i (uint32_t * ucs4, size_t * len, size_t maxucs4len,
               Stringprep_profile_flags flags,
               const Stringprep_profile * profile)
{
  size_t i, j;
  ssize_t k;
  size_t ucs4len = *len;
  int rc;

  for (i = 0; profile[i].operation; i++)
    {
      switch (profile[i].operation)
        {
        case STRINGPREP_NFKC:
          {
            uint32_t *q = 0;

            if (UNAPPLICAPLEFLAGS (flags, profile[i].flags))
              break;

            if (flags & STRINGPREP_NO_NFKC && !profile[i].flags)
              /* Profile requires NFKC, but callee asked for no NFKC. */
              return STRINGPREP_FLAG_ERROR;

            q = stringprep_ucs4_nfkc_normalize (ucs4, ucs4len);
            if (!q)
              return STRINGPREP_NFKC_FAILED;

            for (ucs4len = 0; q[ucs4len]; ucs4len++)
              ;

            if (ucs4len >= maxucs4len)
              {
                free (q);
                return STRINGPREP_TOO_SMALL_BUFFER;
              }

            memcpy (ucs4, q, ucs4len * sizeof (ucs4[0]));

            free (q);
          }
          break;

        case STRINGPREP_PROHIBIT_TABLE:
          k = stringprep_find_string_in_table (ucs4, ucs4len,
                                               NULL, profile[i].table);
          if (k != -1)
            return STRINGPREP_CONTAINS_PROHIBITED;
          break;

        case STRINGPREP_UNASSIGNED_TABLE:
          if (UNAPPLICAPLEFLAGS (flags, profile[i].flags))
            break;
          if (flags & STRINGPREP_NO_UNASSIGNED)
            {
              k = stringprep_find_string_in_table
                (ucs4, ucs4len, NULL, profile[i].table);
              if (k != -1)
                return STRINGPREP_CONTAINS_UNASSIGNED;
            }
          break;

        case STRINGPREP_MAP_TABLE:
          if (UNAPPLICAPLEFLAGS (flags, profile[i].flags))
            break;
          rc = stringprep_apply_table_to_string
            (ucs4, &ucs4len, maxucs4len, profile[i].table);
          if (rc != STRINGPREP_OK)
            return rc;
          break;

        case STRINGPREP_BIDI_PROHIBIT_TABLE:
        case STRINGPREP_BIDI_RAL_TABLE:
        case STRINGPREP_BIDI_L_TABLE:
          break;

        case STRINGPREP_BIDI:
          {
            int done_prohibited = 0;
            int done_ral = 0;
            int done_l = 0;
            int contains_ral = -1;
            int contains_l = -1;

            for (j = 0; profile[j].operation; j++)
              if (profile[j].operation == STRINGPREP_BIDI_PROHIBIT_TABLE)
                {
                  done_prohibited = 1;
                  k = stringprep_find_string_in_table (ucs4, ucs4len,
                                                       NULL,
                                                       profile[j].table);
                  if (k != -1)
                    return STRINGPREP_BIDI_CONTAINS_PROHIBITED;
                }
              else if (profile[j].operation == STRINGPREP_BIDI_RAL_TABLE)
                {
                  done_ral = 1;
                  if (stringprep_find_string_in_table
                      (ucs4, ucs4len, NULL, profile[j].table) != -1)
                    contains_ral = j;
                }
              else if (profile[j].operation == STRINGPREP_BIDI_L_TABLE)
                {
                  done_l = 1;
                  if (stringprep_find_string_in_table
                      (ucs4, ucs4len, NULL, profile[j].table) != -1)
                    contains_l = j;
                }

            if (!done_prohibited || !done_ral || !done_l)
              return STRINGPREP_PROFILE_ERROR;

            if (contains_ral != -1 && contains_l != -1)
              return STRINGPREP_BIDI_BOTH_L_AND_RAL;

            if (contains_ral != -1)
              {
                if (!(stringprep_find_character_in_table
                      (ucs4[0], profile[contains_ral].table) != -1 &&
                      stringprep_find_character_in_table
                      (ucs4[ucs4len - 1], profile[contains_ral].table) != -1))
                  return STRINGPREP_BIDI_LEADTRAIL_NOT_RAL;
              }
          }
          break;

        default:
          return STRINGPREP_PROFILE_ERROR;
          break;
        }
    }

  *len = ucs4len;

  return STRINGPREP_OK;
}

static int
stringprep_4zi_1 (uint32_t * ucs4, size_t ucs4len, size_t maxucs4len,
                  Stringprep_profile_flags flags,
                  const Stringprep_profile * profile)
{
  int rc;

  rc = stringprep_4i (ucs4, &ucs4len, maxucs4len, flags, profile);
  if (rc != STRINGPREP_OK)
    return rc;

  if (ucs4len >= maxucs4len)
    return STRINGPREP_TOO_SMALL_BUFFER;

  ucs4[ucs4len] = 0;

  return STRINGPREP_OK;
}

int
stringprep_4zi (uint32_t * ucs4, size_t maxucs4len,
                Stringprep_profile_flags flags,
                const Stringprep_profile * profile)
{
  size_t ucs4len;

  for (ucs4len = 0; ucs4len < maxucs4len && ucs4[ucs4len] != 0; ucs4len++)
    ;

  return stringprep_4zi_1 (ucs4, ucs4len, maxucs4len, flags, profile);
}

int
stringprep (char *in,
            size_t maxlen,
            Stringprep_profile_flags flags,
            const Stringprep_profile * profile)
{
  int rc;
  char *utf8 = NULL;
  uint32_t *ucs4 = NULL;
  size_t ucs4len, maxucs4len, adducs4len = 50;

  do
    {
      uint32_t *newp;

      if (ucs4)
        free (ucs4);
      ucs4 = stringprep_utf8_to_ucs4 (in, -1, &ucs4len);
      maxucs4len = ucs4len + adducs4len;
      newp = realloc (ucs4, maxucs4len * sizeof (uint32_t));
      if (!newp)
        {
          free (ucs4);
          return STRINGPREP_MALLOC_ERROR;
        }
      ucs4 = newp;

      rc = stringprep_4i (ucs4, &ucs4len, maxucs4len, flags, profile);
      adducs4len += 50;
    }
  while (rc == STRINGPREP_TOO_SMALL_BUFFER);
  if (rc != STRINGPREP_OK)
    {
      free (ucs4);
      return rc;
    }

  utf8 = stringprep_ucs4_to_utf8 (ucs4, ucs4len, 0, 0);
  free (ucs4);
  if (!utf8)
    return STRINGPREP_MALLOC_ERROR;

  if (strlen (utf8) >= maxlen)
    {
      free (utf8);
      return STRINGPREP_TOO_SMALL_BUFFER;
    }

  strcpy (in, utf8);            /* flawfinder: ignore */

  free (utf8);

  return STRINGPREP_OK;
}

int
stringprep_profile (const char *in,
                    char **out,
                    const char *profile, Stringprep_profile_flags flags)
{
  const Stringprep_profiles *p;
  char *str = NULL;
  size_t len = strlen (in) + 1;
  int rc;

  for (p = &stringprep_profiles[0]; p->name; p++)
    if (strcmp (p->name, profile) == 0)
      break;

  if (!p || !p->name || !p->tables)
    return STRINGPREP_UNKNOWN_PROFILE;

  do
    {
      if (str)
        free (str);
      str = (char *) malloc (len);
      if (str == NULL)
        return STRINGPREP_MALLOC_ERROR;

      strcpy (str, in);

      rc = stringprep (str, len, flags, p->tables);
      len += 50;
    }
  while (rc == STRINGPREP_TOO_SMALL_BUFFER);

  if (rc == STRINGPREP_OK)
    *out = str;
  else
    free (str);

  return rc;
}

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