read_wrapper.c

   1 /*
   2  * Copyright 2004 Timo Hirvonen
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU 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  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  17  * 02111-1307, USA.
  18  */
  19
  20 #include "read_wrapper.h"
  21 #include "ip.h"
  22 #include "file.h"
  23
  24 #include <errno.h>
  25 #include <string.h>
  26
  27 ssize_t read_wrapper(struct input_plugin_data *ip_data, void *buffer, size_t count)
  28 {
  29         int rc;
  30
  31         if (ip_data->metaint == 0) {
  32                 /* no metadata in the stream */
  33                 return read(ip_data->fd, buffer, count);
  34         }
  35
  36         if (ip_data->counter == ip_data->metaint) {
  37                 /* read metadata */
  38                 unsigned char byte;
  39                 int len;
  40
  41                 rc = read(ip_data->fd, &byte, 1);
  42                 if (rc == -1)
  43                         return -1;
  44                 if (rc == 0)
  45                         return 0;
  46                 if (byte != 0) {
  47                         len = ((int)byte) * 16;
  48                         ip_data->metadata[0] = 0;
  49                         rc = read_all(ip_data->fd, ip_data->metadata, len);
  50                         if (rc == -1)
  51                                 return -1;
  52                         if (rc < len) {
  53                                 ip_data->metadata[0] = 0;
  54                                 return 0;
  55                         }
  56                         ip_data->metadata[len] = 0;
  57                         ip_data->metadata_changed = 1;
  58                 }
  59                 ip_data->counter = 0;
  60         }
  61         if (count + ip_data->counter > ip_data->metaint)
  62                 count = ip_data->metaint - ip_data->counter;
  63         rc = read(ip_data->fd, buffer, count);
  64         if (rc > 0)
  65                 ip_data->counter += rc;
  66         return rc;
  67 }