gl/getdelim.c

   1 /* getdelim.c --- Implementation of replacement getdelim function.
   2    Copyright (C) 1994, 1996, 1997, 1998, 2001, 2003, 2005, 2006, 2007, 2008,
   3    2009, 2010 Free 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 3, 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 /* Don't use __attribute__ __nonnull__ in this compilation unit.  Otherwise gcc
  25    optimizes away the lineptr == NULL || n == NULL || fp == NULL tests below.  */
  26 #define _GL_ARG_NONNULL(params)
  27
  28 #include <stdio.h>
  29
  30 #include <limits.h>
  31 #include <stdint.h>
  32 #include <stdlib.h>
  33 #include <errno.h>
  34
  35 #ifndef SSIZE_MAX
  36 # define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
  37 #endif
  38
  39 #if USE_UNLOCKED_IO
  40 # include "unlocked-io.h"
  41 # define getc_maybe_unlocked(fp)        getc(fp)
  42 #elif !HAVE_FLOCKFILE || !HAVE_FUNLOCKFILE || !HAVE_DECL_GETC_UNLOCKED
  43 # undef flockfile
  44 # undef funlockfile
  45 # define flockfile(x) ((void) 0)
  46 # define funlockfile(x) ((void) 0)
  47 # define getc_maybe_unlocked(fp)        getc(fp)
  48 #else
  49 # define getc_maybe_unlocked(fp)        getc_unlocked(fp)
  50 #endif
  51
  52 /* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
  53    NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
  54    NULL), pointing to *N characters of space.  It is realloc'ed as
  55    necessary.  Returns the number of characters read (not including
  56    the null terminator), or -1 on error or EOF.  */
  57
  58 ssize_t
  59 getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
  60 {
  61   ssize_t result;
  62   size_t cur_len = 0;
  63
  64   if (lineptr == NULL || n == NULL || fp == NULL)
  65     {
  66       errno = EINVAL;
  67       return -1;
  68     }
  69
  70   flockfile (fp);
  71
  72   if (*lineptr == NULL || *n == 0)
  73     {
  74       char *new_lineptr;
  75       *n = 120;
  76       new_lineptr = (char *) realloc (*lineptr, *n);
  77       if (new_lineptr == NULL)
  78         {
  79           result = -1;
  80           goto unlock_return;
  81         }
  82       *lineptr = new_lineptr;
  83     }
  84
  85   for (;;)
  86     {
  87       int i;
  88
  89       i = getc_maybe_unlocked (fp);
  90       if (i == EOF)
  91         {
  92           result = -1;
  93           break;
  94         }
  95
  96       /* Make enough space for len+1 (for final NUL) bytes.  */
  97       if (cur_len + 1 >= *n)
  98         {
  99           size_t needed_max =
 100             SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
 101           size_t needed = 2 * *n + 1;   /* Be generous. */
 102           char *new_lineptr;
 103
 104           if (needed_max < needed)
 105             needed = needed_max;
 106           if (cur_len + 1 >= needed)
 107             {
 108               result = -1;
 109               errno = EOVERFLOW;
 110               goto unlock_return;
 111             }
 112
 113           new_lineptr = (char *) realloc (*lineptr, needed);
 114           if (new_lineptr == NULL)
 115             {
 116               result = -1;
 117               goto unlock_return;
 118             }
 119
 120           *lineptr = new_lineptr;
 121           *n = needed;
 122         }
 123
 124       (*lineptr)[cur_len] = i;
 125       cur_len++;
 126
 127       if (i == delimiter)
 128         break;
 129     }
 130   (*lineptr)[cur_len] = '\0';
 131   result = cur_len ? cur_len : result;
 132
 133  unlock_return:
 134   funlockfile (fp); /* doesn't set errno */
 135
 136   return result;
 137 }