gl/getdelim.c

   1 /* getdelim.c --- Implementation of replacement getdelim function.
   2    Copyright (C) 1994, 1996, 1997, 1998, 2001, 2003, 2005 Free
   3    Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU General Public License as
   7    published by the Free Software Foundation; either version 2, or (at
   8    your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful, but
  11    WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18    02110-1301, USA.  */
  19
  20 /* Ported from glibc by Simon Josefsson. */
  21
  22 #ifdef HAVE_CONFIG_H
  23 # include <config.h>
  24 #endif
  25
  26 #include "getdelim.h"
  27
  28 #include <limits.h>
  29 #include <stdlib.h>
  30 #include <errno.h>
  31
  32 #ifndef SIZE_MAX
  33 # define SIZE_MAX ((size_t) -1)
  34 #endif
  35 #ifndef SSIZE_MAX
  36 # define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
  37 #endif
  38 #if !HAVE_FLOCKFILE
  39 # undef flockfile
  40 # define flockfile(x) ((void) 0)
  41 #endif
  42 #if !HAVE_FUNLOCKFILE
  43 # undef funlockfile
  44 # define funlockfile(x) ((void) 0)
  45 #endif
  46
  47 /* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
  48    NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
  49    NULL), pointing to *N characters of space.  It is realloc'ed as
  50    necessary.  Returns the number of characters read (not including
  51    the null terminator), or -1 on error or EOF.  */
  52
  53 ssize_t
  54 getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
  55 {
  56   ssize_t result;
  57   size_t cur_len = 0;
  58
  59   if (lineptr == NULL || n == NULL || fp == NULL)
  60     {
  61       errno = EINVAL;
  62       return -1;
  63     }
  64
  65   flockfile (fp);
  66
  67   if (*lineptr == NULL || *n == 0)
  68     {
  69       *n = 120;
  70       *lineptr = (char *) malloc (*n);
  71       if (*lineptr == NULL)
  72         {
  73           result = -1;
  74           goto unlock_return;
  75         }
  76     }
  77
  78   for (;;)
  79     {
  80       int i;
  81
  82       i = getc (fp);
  83       if (i == EOF)
  84         {
  85           result = -1;
  86           break;
  87         }
  88
  89       /* Make enough space for len+1 (for final NUL) bytes.  */
  90       if (cur_len + 1 >= *n)
  91         {
  92           size_t needed_max =
  93             SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
  94           size_t needed = 2 * *n + 1;   /* Be generous. */
  95           char *new_lineptr;
  96
  97           if (needed_max < needed)
  98             needed = needed_max;
  99           if (cur_len + 1 >= needed)
 100             {
 101               result = -1;
 102               goto unlock_return;
 103             }
 104
 105           new_lineptr = (char *) realloc (*lineptr, needed);
 106           if (new_lineptr == NULL)
 107             {
 108               result = -1;
 109               goto unlock_return;
 110             }
 111
 112           *lineptr = new_lineptr;
 113           *n = needed;
 114         }
 115
 116       (*lineptr)[cur_len] = i;
 117       cur_len++;
 118
 119       if (i == delimiter)
 120         break;
 121     }
 122   (*lineptr)[cur_len] = '\0';
 123   result = cur_len ? cur_len : result;
 124
 125  unlock_return:
 126   funlockfile (fp);
 127   return result;
 128 }