/* Copyright 1998 by the Massachusetts Institute of Technology.

 *

 * Permission to use, copy, modify, and distribute this

 * software and its documentation for any purpose and without

 * fee is hereby granted, provided that the above copyright

 * notice appear in all copies and that both that copyright

 * notice and this permission notice appear in supporting

 * documentation, and that the name of M.I.T. not be used in

 * advertising or publicity pertaining to distribution of the

 * software without specific, written prior permission.

 * M.I.T. makes no representations about the suitability of

 * this software for any purpose.  It is provided "as is"

 * without express or implied warranty.

 */

#include "ares_setup.h"

#include "ares.h"

#include "ares_nowarn.h"

#include "ares_private.h"

/* This is an internal function.  Its contract is to read a line from

 * a file into a dynamically allocated buffer, zeroing the trailing

 * newline if there is one.  The calling routine may call

 * ares__read_line multiple times with the same buf and bufsize

 * pointers; *buf will be reallocated and *bufsize adjusted as

 * appropriate.  The initial value of *buf should be NULL.  After the

 * calling routine is done reading lines, it should free *buf.

 */

int ares__read_line(FILE *fp, char **buf, size_t *bufsize)

{

  char *newbuf;

  size_t offset = 0;

  size_t len;

  if (*buf == NULL)

    {

      *buf = ares_malloc(128);

      if (!*buf)

        return ARES_ENOMEM;

      *bufsize = 128;

    }

  for (;;)

    {

      int bytestoread = aresx_uztosi(*bufsize - offset);

      if (!fgets(*buf + offset, bytestoread, fp))

        return (offset != 0) ? 0 : (ferror(fp)) ? ARES_EFILE : ARES_EOF;

      len = offset + strlen(*buf + offset);

      if ((*buf)[len - 1] == '\n')

        {

          (*buf)[len - 1] = 0;

          break;

        }

      offset = len;

      if(len < *bufsize - 1)

        continue;

      /* Allocate more space. */

      newbuf = ares_realloc(*buf, *bufsize * 2);

      if (!newbuf)

        {

          ares_free(*buf);

          *buf = NULL;

          return ARES_ENOMEM;

        }

      *buf = newbuf;

      *bufsize *= 2;

    }

  return ARES_SUCCESS;

}