libc/stdio/getdelim.c

   1 /* Copyright (C) 2004       Manuel Novoa III    <mjn3@codepoet.org>
   2  *
   3  * GNU Library General Public License (LGPL) version 2 or later.
   4  *
   5  * Dedicated to Toni.  See uClibc/DEDICATION.mjn3 for details.
   6  */
   7
   8 #include <features.h>
   9
  10 #ifdef __USE_GNU
  11 #include "_stdio.h"
  12
  13
  14
  15 /* Note: There is a defect in this function.  (size_t vs ssize_t). */
  16
  17 /* glibc function --
  18  * Return -1 if error or EOF prior to any chars read.
  19  * Return number of chars read (including possible delimiter but not
  20  *   the terminating nul) otherwise.
  21  *
  22  * NOTE: If we need to allocate a buffer, we do so prior to attempting
  23  * a reading.  So space may be allocated even if initially at EOF.
  24  */
  25
  26 #define GETDELIM_GROWBY         64
  27
  28 ssize_t getdelim(char **__restrict lineptr, size_t *__restrict n,
  29                                    int delimiter, register FILE *__restrict stream)
  30 {
  31         register char *buf;
  32         ssize_t pos = -1;
  33         int c;
  34         __STDIO_AUTO_THREADLOCK_VAR;
  35
  36         if (!lineptr || !n || !stream) { /* Be compatable with glibc... even */
  37                 __set_errno(EINVAL); /* though I think we should assert here */
  38         } else {
  39                 __STDIO_AUTO_THREADLOCK(stream);
  40
  41                 if (!(buf = *lineptr)) { /* If passed NULL for buffer, */
  42                         *n = 0;         /* ignore value passed and treat size as 0. */
  43                 }
  44
  45                 /* Within the loop, pos is actually the current buffer index + 2,
  46                  * because we want to make sure we have enough space to store
  47                  * an additional char plus a nul terminator.
  48                  */
  49                 pos = 1;
  50
  51                 do {
  52                         if (pos >= *n) {
  53                                 if (!(buf = realloc(buf, *n + GETDELIM_GROWBY))) {
  54                                         pos = -1;
  55                                         break;
  56                                 }
  57                                 *n += GETDELIM_GROWBY;
  58                                 *lineptr = buf;
  59                         }
  60
  61                         if ((c = __GETC_UNLOCKED(stream)) != EOF) {
  62                                 buf[++pos - 2] = c;
  63                                 if (c != delimiter) {
  64                                         continue;
  65                                 }
  66                         }
  67
  68                         /* We're done, so correct pos back to being the current index. */
  69                         if ((pos -= 2) >= 0) {
  70                                 buf[++pos] = 0;
  71                         }
  72                         break;
  73
  74                 } while (1);
  75
  76                 __STDIO_AUTO_THREADUNLOCK(stream);
  77         }
  78
  79         return pos;
  80 }
  81 libc_hidden_def(getdelim)
  82 #endif