incorrect wcsrtombs

[Bruno Haible <haible at ilog dot fr>]

In glibc-2000-04-12, there is a bug in function wcsrtombs (and also
wcsnrtombs): The test program

====================== test_utf8_wcsrtombs.c =============================
/* Test restarting behaviour of wcsrtombs. */

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

#define show(expr)  { size_t res = expr; printf(#expr " -> %d",res); dst += res; printf(", src = srcbuf+%d, dst = buf+%d\n",src-srcbuf,dst-(char*)buf); }

int main ()
{
  unsigned char buf [6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  unsigned char bufcheck [6] = { 0x25,  0xe2, 0x82, 0xac,  0xce, 0xbb };
  wchar_t srcbuf [4] = { 0x25, 0x20ac, 0x03bb, 0 };
  mbstate_t state;
  const wchar_t * src;
  char * dst;

  setlocale(LC_CTYPE,"de_DE.UTF-8");
  memset(&state,0,sizeof(state));
  src = srcbuf;
  dst = (char *) buf;
  show(wcsrtombs(dst,&src,1,&state));
  show(wcsrtombs(dst,&src,1,&state));
  show(wcsrtombs(dst,&src,3,&state));
  show(wcsrtombs(dst,&src,1,&state));

  if (memcmp(buf,bufcheck,6)) {
    printf("wrong results\n");
  }

  return 0;
}

/* Expected output:

wcsrtombs(dst,&src,1,&state) -> 1, src = srcbuf+1, dst = buf+1
wcsrtombs(dst,&src,1,&state) -> 1, src = srcbuf+2, dst = buf+2
wcsrtombs(dst,&src,3,&state) -> 3, src = srcbuf+3, dst = buf+5
wcsrtombs(dst,&src,1,&state) -> 1, src = srcbuf+3, dst = buf+6

*/

/* Output of a non-restarting implementation:

wcsrtombs(dst,&src,1,&state) -> 1, src = srcbuf+1, dst = buf+1
wcsrtombs(dst,&src,1,&state) -> 0, src = srcbuf+1, dst = buf+1
wcsrtombs(dst,&src,3,&state) -> 3, src = srcbuf+2, dst = buf+4
wcsrtombs(dst,&src,1,&state) -> 0, src = srcbuf+2, dst = buf+4
wrong results

*/
==========================================================================

$ localedef -c -f UTF8 -i de_DE de_DE.UTF-8
$ ./test_utf8_wcsrtombs

prints

wcsrtombs(dst,&src,1,&state) -> 1, src = srcbuf+1, dst = buf+1
wcsrtombs(dst,&src,1,&state) -> 0, src = srcbuf+1, dst = buf+1
wcsrtombs(dst,&src,3,&state) -> 0, src = srcbuf+1, dst = buf+1
wcsrtombs(dst,&src,1,&state) -> 0, src = srcbuf+1, dst = buf+1
wrong results