usr/src/lib/libc/port/locale/ungetwc.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1986 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 /*
  31  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
  32  */
  33
  34 /*      This module is created for NLS on Sep.03.86             */
  35
  36 /*
  37  * Ungetwc saves the process code c into the one character buffer
  38  * associated with an input stream "iop". That character, c,
  39  * will be returned by the next getwc call on that stream.
  40  */
  41
  42 #include "lint.h"
  43 #include "file64.h"
  44 #include "mse_int.h"
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <widec.h>
  48 #include <limits.h>
  49 #include <errno.h>
  50 #include "libc.h"
  51 #include "stdiom.h"
  52 #include "mse.h"
  53
  54 static wint_t
  55 __ungetwc_impl(wint_t wc, FILE *iop, int orient)
  56 {
  57         char            mbs[MB_LEN_MAX];
  58         unsigned char   *p;
  59         int             n;
  60         rmutex_t        *lk;
  61
  62         FLOCKFILE(lk, iop);
  63
  64         if (orient && GET_NO_MODE(iop)) {
  65                 _setorientation(iop, _WC_MODE);
  66         }
  67         if ((wc == WEOF) || ((iop->_flag & _IOREAD) == 0)) {
  68                 FUNLOCKFILE(lk);
  69                 return (WEOF);
  70         }
  71
  72         n = wctomb(mbs, (wchar_t)wc);
  73         if (n <= 0) {
  74                 FUNLOCKFILE(lk);
  75                 return (WEOF);
  76         }
  77
  78         if (iop->_ptr <= iop->_base) {
  79                 if (iop->_base == NULL) {
  80                         FUNLOCKFILE(lk);
  81                         return (WEOF);
  82                 }
  83                 if (iop->_ptr == iop->_base && iop->_cnt == 0) {
  84                         ++iop->_ptr;
  85                 } else if ((iop->_ptr - n) < (iop->_base - PUSHBACK)) {
  86                         FUNLOCKFILE(lk);
  87                         return (WEOF);
  88                 }
  89         }
  90
  91         p = (unsigned char *)(mbs + n - 1);
  92         while (n--) {
  93                 *--(iop)->_ptr = (*p--);
  94                 ++(iop)->_cnt;
  95         }
  96         iop->_flag &= ~_IOEOF;
  97         FUNLOCKFILE(lk);
  98         return (wc);
  99 }
 100
 101
 102 wint_t
 103 __ungetwc_xpg5(wint_t wc, FILE *iop)
 104 {
 105         return (__ungetwc_impl(wc, iop, 1));
 106 }
 107
 108 wint_t
 109 ungetwc(wint_t wc, FILE *iop)
 110 {
 111         return (__ungetwc_impl(wc, iop, 0));
 112 }