1  /* Copyright (C) 2011-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <assert.h>
      19  #include <dlfcn.h>
      20  #include <errno.h>
      21  #include <gconv.h>
      22  #include <uchar.h>
      23  #include <wcsmbsload.h>
      24  
      25  #include <pointer_guard.h>
      26  
      27  #ifndef EILSEQ
      28  # define EILSEQ EINVAL
      29  #endif
      30  
      31  
      32  /* This is the private state used if PS is NULL.  */
      33  static mbstate_t state;
      34  
      35  size_t
      36  mbrtoc16 (char16_t *pc16, const char *s, size_t n, mbstate_t *ps)
      37  {
      38    if (ps == NULL)
      39      ps = &state;
      40  
      41    /* The standard text does not say that S being NULL means the state
      42       is reset even if the second half of a surrogate still have to be
      43       returned.  In fact, the error code description indicates
      44       otherwise.  Therefore always first try to return a second
      45       half.  */
      46    if (ps->__count & 0x80000000)
      47      {
      48        /* We have to return the second word for a surrogate.  */
      49        ps->__count &= 0x7fffffff;
      50        *pc16 = ps->__value.__wch;
      51        ps->__value.__wch = L'\0';
      52        return (size_t) -3;
      53      }
      54  
      55    wchar_t wc;
      56    struct __gconv_step_data data;
      57    int status;
      58    size_t result;
      59    size_t dummy;
      60    const unsigned char *inbuf, *endbuf;
      61    unsigned char *outbuf = (unsigned char *) &wc;
      62    const struct gconv_fcts *fcts;
      63  
      64    /* Set information for this step.  */
      65    data.__invocation_counter = 0;
      66    data.__internal_use = 1;
      67    data.__flags = __GCONV_IS_LAST;
      68    data.__statep = ps;
      69  
      70    /* A first special case is if S is NULL.  This means put PS in the
      71       initial state.  */
      72    if (s == NULL)
      73      {
      74        pc16 = NULL;
      75        s = "";
      76        n = 1;
      77      }
      78  
      79    if (n == 0)
      80      return (size_t) -2;
      81  
      82    /* Tell where we want the result.  */
      83    data.__outbuf = outbuf;
      84    data.__outbufend = outbuf + sizeof (wchar_t);
      85  
      86    /* Get the conversion functions.  */
      87    fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
      88  
      89    /* Do a normal conversion.  */
      90    inbuf = (const unsigned char *) s;
      91    endbuf = inbuf + n;
      92    if (__glibc_unlikely (endbuf < inbuf))
      93      {
      94        endbuf = (const unsigned char *) ~(uintptr_t) 0;
      95        if (endbuf == inbuf)
      96  	goto ilseq;
      97      }
      98    __gconv_fct fct = fcts->towc->__fct;
      99    if (fcts->towc->__shlib_handle != NULL)
     100      PTR_DEMANGLE (fct);
     101  
     102    status = DL_CALL_FCT (fct, (fcts->towc, &data, &inbuf, endbuf,
     103  			      NULL, &dummy, 0, 1));
     104  
     105    /* There must not be any problems with the conversion but illegal input
     106       characters.  The output buffer must be large enough, otherwise the
     107       definition of MB_CUR_MAX is not correct.  All the other possible
     108       errors also must not happen.  */
     109    assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
     110  	  || status == __GCONV_ILLEGAL_INPUT
     111  	  || status == __GCONV_INCOMPLETE_INPUT
     112  	  || status == __GCONV_FULL_OUTPUT);
     113  
     114    if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
     115        || status == __GCONV_FULL_OUTPUT)
     116      {
     117        result = inbuf - (const unsigned char *) s;
     118  
     119        if (wc < 0x10000)
     120  	{
     121  	  if (pc16 != NULL)
     122  	    *pc16 = wc;
     123  
     124  	  if (data.__outbuf != outbuf && wc == L'\0')
     125  	    {
     126  	      /* The converted character is the NUL character.  */
     127  	      assert (__mbsinit (data.__statep));
     128  	      result = 0;
     129  	    }
     130  	}
     131        else
     132  	{
     133  	  /* This is a surrogate.  */
     134  	  if (pc16 != NULL)
     135  	    *pc16 = 0xd7c0 + (wc >> 10);
     136  
     137  	  ps->__count |= 0x80000000;
     138  	  ps->__value.__wch = 0xdc00 + (wc & 0x3ff);
     139  	}
     140      }
     141    else if (status == __GCONV_INCOMPLETE_INPUT)
     142      result = (size_t) -2;
     143    else
     144      {
     145      ilseq:
     146        result = (size_t) -1;
     147        __set_errno (EILSEQ);
     148      }
     149  
     150    return result;
     151  }