stdio/getdelim.c

   1 /* Copyright (C) 1991, 1992, 1995, 1996, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <stddef.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <limits.h>
  24 #include <errno.h>
  25
  26 /* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR
  27    (and null-terminate it). *LINEPTR is a pointer returned from malloc (or
  28    NULL), pointing to *N characters of space.  It is realloc'd as
  29    necessary.  Returns the number of characters read (not including the
  30    null terminator), or -1 on error or EOF.  */
  31
  32 ssize_t
  33 __getdelim (lineptr, n, terminator, stream)
  34      char **lineptr;
  35      size_t *n;
  36      int terminator;
  37      FILE *stream;
  38 {
  39   char *line, *p;
  40   size_t size, copy;
  41
  42   if (!__validfp (stream) || lineptr == NULL || n == NULL)
  43     {
  44       __set_errno (EINVAL);
  45       return -1;
  46     }
  47
  48   if (ferror (stream))
  49     return -1;
  50
  51   /* Make sure we have a line buffer to start with.  */
  52   if (*lineptr == NULL || *n < 2) /* !seen and no buf yet need 2 chars.  */
  53     {
  54 #ifndef MAX_CANON
  55 #define MAX_CANON       256
  56 #endif
  57       line = realloc (*lineptr, MAX_CANON);
  58       if (line == NULL)
  59         return -1;
  60       *lineptr = line;
  61       *n = MAX_CANON;
  62     }
  63
  64   line = *lineptr;
  65   size = *n;
  66
  67   copy = size;
  68   p = line;
  69
  70   if (stream->__buffer == NULL && stream->__userbuf)
  71     {
  72       /* Unbuffered stream.  Not much optimization to do.  */
  73
  74       while (1)
  75         {
  76           size_t len;
  77
  78           while (--copy > 0)
  79             {
  80               register int c = getc (stream);
  81               if (c == EOF)
  82                 goto lose;
  83               else if ((*p++ = c) == terminator)
  84                 goto win;
  85             }
  86
  87           /* Need to enlarge the line buffer.  */
  88           len = p - line;
  89           size *= 2;
  90           line = realloc (line, size);
  91           if (line == NULL)
  92             goto lose;
  93           *lineptr = line;
  94           *n = size;
  95           p = line + len;
  96           copy = size - len;
  97         }
  98     }
  99   else
 100     {
 101       /* Leave space for the terminating null.  */
 102       --copy;
 103
 104       if (!stream->__seen || stream->__buffer == NULL || stream->__pushed_back)
 105         {
 106           /* Do one with getc to allocate a buffer.  */
 107           int c = getc (stream);
 108           if (c == EOF)
 109             goto lose;
 110           *p++ = c;
 111           if (c == terminator)
 112             goto win;
 113           --copy;
 114         }
 115
 116       while (1)
 117         {
 118           size_t i;
 119           char *found;
 120
 121           i = stream->__get_limit - stream->__bufp;
 122           if (i == 0)
 123             {
 124               /* Refill the buffer.  */
 125               int c = __fillbf (stream);
 126               if (c == EOF)
 127                 goto lose;
 128               *p++ = c;
 129               if (c == terminator)
 130                 goto win;
 131               --copy;
 132               i = stream->__get_limit - stream->__bufp;
 133             }
 134
 135           if (i > copy)
 136             i = copy;
 137
 138           found = (char *) __memccpy ((void *) p, stream->__bufp,
 139                                       terminator, i);
 140           if (found != NULL)
 141             {
 142               stream->__bufp += found - p;
 143               p = found;
 144               goto win;
 145             }
 146
 147           stream->__bufp += i;
 148           p += i;
 149           copy -= i;
 150           if (copy == 0)
 151             {
 152               /* Need to enlarge the line buffer.  */
 153               size_t len = p - line;
 154               size *= 2;
 155               line = realloc (line, size);
 156               if (line == NULL)
 157                 goto lose;
 158               *lineptr = line;
 159               *n = size;
 160               p = line + len;
 161               copy = size - len;
 162               /* Leave space for the terminating null.  */
 163               --copy;
 164             }
 165         }
 166     }
 167
 168  lose:
 169   if (p == *lineptr)
 170     return -1;
 171   /* Return a partial line since we got an error in the middle.  */
 172  win:
 173   *p = '\0';
 174   return p - *lineptr;
 175 }
 176
 177 weak_alias (__getdelim, getdelim)