gl/getdelim.c

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