gl/getdelim.c

   1 /* getdelim.c --- Implementation of replacement getdelim function.
   2    Copyright (C) 1994, 1996-1998, 2001, 2003, 2005-2012 Free Software
   3    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, see <http://www.gnu.org/licenses/>.  */
  17
  18 /* Ported from glibc by Simon Josefsson. */
  19
  20 #include <config.h>
  21
  22 /* Don't use __attribute__ __nonnull__ in this compilation unit.  Otherwise gcc
  23    optimizes away the lineptr == NULL || n == NULL || fp == NULL tests below.  */
  24 #define _GL_ARG_NONNULL(params)
  25
  26 #include <stdio.h>
  27
  28 #include <limits.h>
  29 #include <stdint.h>
  30 #include <stdlib.h>
  31 #include <errno.h>
  32
  33 #ifndef SSIZE_MAX
  34 # define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
  35 #endif
  36
  37 #if USE_UNLOCKED_IO
  38 # include "unlocked-io.h"
  39 # define getc_maybe_unlocked(fp)        getc(fp)
  40 #elif !HAVE_FLOCKFILE || !HAVE_FUNLOCKFILE || !HAVE_DECL_GETC_UNLOCKED
  41 # undef flockfile
  42 # undef funlockfile
  43 # define flockfile(x) ((void) 0)
  44 # define funlockfile(x) ((void) 0)
  45 # define getc_maybe_unlocked(fp)        getc(fp)
  46 #else
  47 # define getc_maybe_unlocked(fp)        getc_unlocked(fp)
  48 #endif
  49
  50 /* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
  51    NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
  52    NULL), pointing to *N characters of space.  It is realloc'ed as
  53    necessary.  Returns the number of characters read (not including
  54    the null terminator), or -1 on error or EOF.  */
  55
  56 ssize_t
  57 getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
  58 {
  59   ssize_t result;
  60   size_t cur_len = 0;
  61
  62   if (lineptr == NULL || n == NULL || fp == NULL)
  63     {
  64       errno = EINVAL;
  65       return -1;
  66     }
  67
  68   flockfile (fp);
  69
  70   if (*lineptr == NULL || *n == 0)
  71     {
  72       char *new_lineptr;
  73       *n = 120;
  74       new_lineptr = (char *) realloc (*lineptr, *n);
  75       if (new_lineptr == NULL)
  76         {
  77           result = -1;
  78           goto unlock_return;
  79         }
  80       *lineptr = new_lineptr;
  81     }
  82
  83   for (;;)
  84     {
  85       int i;
  86
  87       i = getc_maybe_unlocked (fp);
  88       if (i == EOF)
  89         {
  90           result = -1;
  91           break;
  92         }
  93
  94       /* Make enough space for len+1 (for final NUL) bytes.  */
  95       if (cur_len + 1 >= *n)
  96         {
  97           size_t needed_max =
  98             SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
  99           size_t needed = 2 * *n + 1;   /* Be generous. */
 100           char *new_lineptr;
 101
 102           if (needed_max < needed)
 103             needed = needed_max;
 104           if (cur_len + 1 >= needed)
 105             {
 106               result = -1;
 107               errno = EOVERFLOW;
 108               goto unlock_return;
 109             }
 110
 111           new_lineptr = (char *) realloc (*lineptr, needed);
 112           if (new_lineptr == NULL)
 113             {
 114               result = -1;
 115               goto unlock_return;
 116             }
 117
 118           *lineptr = new_lineptr;
 119           *n = needed;
 120         }
 121
 122       (*lineptr)[cur_len] = i;
 123       cur_len++;
 124
 125       if (i == delimiter)
 126         break;
 127     }
 128   (*lineptr)[cur_len] = '\0';
 129   result = cur_len ? cur_len : result;
 130
 131  unlock_return:
 132   funlockfile (fp); /* doesn't set errno */
 133
 134   return result;
 135 }