StdLib/LibC/Stdio/fgetstr.c

   1 /*
   2     Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
   3     This program and the accompanying materials are licensed and made available
   4     under the terms and conditions of the BSD License that accompanies this
   5     distribution.  The full text of the license may be found at
   6     http://opensource.org/licenses/bsd-license.
   7
   8     THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   9     WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  10
  11  * Copyright (c) 1990, 1993
  12  *  The Regents of the University of California.  All rights reserved.
  13  *
  14  * This code is derived from software contributed to Berkeley by
  15  * Chris Torek.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  * 3. Neither the name of the University nor the names of its contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40
  41     $NetBSD: fgetstr.c,v 1.4 2006/11/24 19:46:58 christos Exp $
  42     fgetline.c  8.1 (Berkeley) 6/4/93
  43 */
  44
  45 /*-
  46  */
  47 #include  <LibConfig.h>
  48 #include <sys/EfiCdefs.h>
  49
  50 #include "namespace.h"
  51
  52 #include <assert.h>
  53 #include  <errno.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include "reentrant.h"
  58 #include "local.h"
  59
  60 /*
  61  * Expand the line buffer.  Return -1 on error.
  62 #ifdef notdef
  63  * The `new size' does not account for a terminating '\0',
  64  * so we add 1 here.
  65 #endif
  66  */
  67 int
  68 __slbexpand(FILE *fp, size_t newsize)
  69 {
  70   void *p;
  71
  72 #ifdef notdef
  73   ++newsize;
  74 #endif
  75   _DIAGASSERT(fp != NULL);
  76   if(fp == NULL) {
  77     errno = EINVAL;
  78     return (-1);
  79   }
  80
  81   if ((size_t)fp->_lb._size >= newsize)
  82     return (0);
  83   if ((p = realloc(fp->_lb._base, newsize)) == NULL)
  84     return (-1);
  85   fp->_lb._base = p;
  86   fp->_lb._size = (int)newsize;
  87   return (0);
  88 }
  89
  90 /*
  91  * Get an input line.  The returned pointer often (but not always)
  92  * points into a stdio buffer.  Fgetline does not alter the text of
  93  * the returned line (which is thus not a C string because it will
  94  * not necessarily end with '\0'), but does allow callers to modify
  95  * it if they wish.  Thus, we set __SMOD in case the caller does.
  96  */
  97 char *
  98 __fgetstr(FILE *fp, size_t *lenp, int sep)
  99 {
 100   unsigned char *p;
 101   size_t len;
 102   size_t off;
 103
 104   _DIAGASSERT(fp != NULL);
 105   _DIAGASSERT(lenp != NULL);
 106   if(fp == NULL) {
 107     errno = EINVAL;
 108     return (NULL);
 109   }
 110
 111   /* make sure there is input */
 112   if (fp->_r <= 0 && __srefill(fp)) {
 113     *lenp = 0;
 114     return (NULL);
 115   }
 116
 117   /* look for a newline in the input */
 118   if ((p = memchr((void *)fp->_p, sep, (size_t)fp->_r)) != NULL) {
 119     char *ret;
 120
 121     /*
 122      * Found one.  Flag buffer as modified to keep fseek from
 123      * `optimising' a backward seek, in case the user stomps on
 124      * the text.
 125      */
 126     p++;    /* advance over it */
 127     ret = (char *)fp->_p;
 128     *lenp = len = p - fp->_p;
 129     fp->_flags |= __SMOD;
 130     fp->_r -= (int)len;
 131     fp->_p = p;
 132     return (ret);
 133   }
 134
 135   /*
 136    * We have to copy the current buffered data to the line buffer.
 137    * As a bonus, though, we can leave off the __SMOD.
 138    *
 139    * OPTIMISTIC is length that we (optimistically) expect will
 140    * accommodate the `rest' of the string, on each trip through the
 141    * loop below.
 142    */
 143 #define OPTIMISTIC 80
 144
 145   for (len = fp->_r, off = 0;; len += fp->_r) {
 146     size_t diff;
 147
 148     /*
 149      * Make sure there is room for more bytes.  Copy data from
 150      * file buffer to line buffer, refill file and look for
 151      * newline.  The loop stops only when we find a newline.
 152      */
 153     if (__slbexpand(fp, len + OPTIMISTIC))
 154       goto error;
 155     (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,
 156         len - off);
 157     off = len;
 158     if (__srefill(fp))
 159       break;  /* EOF or error: return partial line */
 160     if ((p = memchr((void *)fp->_p, sep, (size_t)fp->_r)) == NULL)
 161       continue;
 162
 163     /* got it: finish up the line (like code above) */
 164     p++;
 165     diff = p - fp->_p;
 166     len += diff;
 167     if (__slbexpand(fp, len))
 168       goto error;
 169     (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,
 170         diff);
 171     fp->_r -= (int)diff;
 172     fp->_p = p;
 173     break;
 174   }
 175   *lenp = len;
 176 #ifdef notdef
 177   fp->_lb._base[len] = 0;
 178 #endif
 179   return ((char *)fp->_lb._base);
 180
 181 error:
 182   *lenp = 0;    /* ??? */
 183   return (NULL);    /* ??? */
 184 }