gl/getdelim.c

   1 /* getdelim.c --- Implementation of replacement getdelim function.
   2    Copyright (C) 1994, 1996, 1997, 1998, 2001, 2003, 2005, 2006 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 #include <config.h>
  23
  24 #include "getdelim.h"
  25
  26 #include <limits.h>
  27 #include <stdlib.h>
  28 #include <errno.h>
  29
  30 #ifndef SIZE_MAX
  31 # define SIZE_MAX ((size_t) -1)
  32 #endif
  33 #ifndef SSIZE_MAX
  34 # define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
  35 #endif
  36 #if !HAVE_FLOCKFILE
  37 # undef flockfile
  38 # define flockfile(x) ((void) 0)
  39 #endif
  40 #if !HAVE_FUNLOCKFILE
  41 # undef funlockfile
  42 # define funlockfile(x) ((void) 0)
  43 #endif
  44
  45 /* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
  46    NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
  47    NULL), pointing to *N characters of space.  It is realloc'ed as
  48    necessary.  Returns the number of characters read (not including
  49    the null terminator), or -1 on error or EOF.  */
  50
  51 ssize_t
  52 getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
  53 {
  54   ssize_t result;
  55   size_t cur_len = 0;
  56
  57   if (lineptr == NULL || n == NULL || fp == NULL)
  58     {
  59       errno = EINVAL;
  60       return -1;
  61     }
  62
  63   flockfile (fp);
  64
  65   if (*lineptr == NULL || *n == 0)
  66     {
  67       *n = 120;
  68       *lineptr = (char *) malloc (*n);
  69       if (*lineptr == NULL)
  70         {
  71           result = -1;
  72           goto unlock_return;
  73         }
  74     }
  75
  76   for (;;)
  77     {
  78       int i;
  79
  80       i = getc (fp);
  81       if (i == EOF)
  82         {
  83           result = -1;
  84           break;
  85         }
  86
  87       /* Make enough space for len+1 (for final NUL) bytes.  */
  88       if (cur_len + 1 >= *n)
  89         {
  90           size_t needed_max =
  91             SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
  92           size_t needed = 2 * *n + 1;   /* Be generous. */
  93           char *new_lineptr;
  94
  95           if (needed_max < needed)
  96             needed = needed_max;
  97           if (cur_len + 1 >= needed)
  98             {
  99               result = -1;
 100               goto unlock_return;
 101             }
 102
 103           new_lineptr = (char *) realloc (*lineptr, needed);
 104           if (new_lineptr == NULL)
 105             {
 106               result = -1;
 107               goto unlock_return;
 108             }
 109
 110           *lineptr = new_lineptr;
 111           *n = needed;
 112         }
 113
 114       (*lineptr)[cur_len] = i;
 115       cur_len++;
 116
 117       if (i == delimiter)
 118         break;
 119     }
 120   (*lineptr)[cur_len] = '\0';
 121   result = cur_len ? cur_len : result;
 122
 123  unlock_return:
 124   funlockfile (fp);
 125   return result;
 126 }