/*
    This file is part of Mtproto-proxy Library.

    Mtproto-proxy Library is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    Mtproto-proxy Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with Mtproto-proxy Library.  If not, see <http://www.gnu.org/licenses/>.

    Copyright 2012-2013 Vkontakte Ltd
              2012-2013 Nikolai Durov
              2012-2013 Andrey Lopatin
    
    Copyright 2014-2016 Telegram Messenger Inc             
              2015-2016 Vitaly Valtman
*/

#pragma once

#include <assert.h>
#include "common/mp-queue.h"

#define MSG_STD_BUFFER	2048
#define	MSG_SMALL_BUFFER	512
#define	MSG_TINY_BUFFER	48

#define	MSG_BUFFERS_CHUNK_SIZE	((1L << 21) - 64)

#define MSG_DEFAULT_MAX_ALLOCATED_BYTES	(1L << 28)

#ifdef _LP64
#define MSG_MAX_ALLOCATED_BYTES	(1L << 40)
#else
#define MSG_MAX_ALLOCATED_BYTES	(1L << 30)
#endif

#define MSG_BUFFER_FREE_MAGIC	0x4abdc351
#define MSG_BUFFER_USED_MAGIC	0x72e39317
#define	MSG_BUFFER_SPECIAL_MAGIC	0x683caad3

#define MSG_CHUNK_USED_MAGIC	0x5c75e681
#define MSG_CHUNK_USED_LOCKED_MAGIC	(~MSG_CHUNK_USED_MAGIC)
#define MSG_CHUNK_HEAD_MAGIC	0x2dfecca3
#define MSG_CHUNK_HEAD_LOCKED_MAGIC	(~MSG_CHUNK_HEAD_MAGIC)

#define	MAX_BUFFER_SIZE_VALUES	16

#define	BUFF_HD_BYTES	(offsetof (struct msg_buffer, data))

struct msg_buffer {
  struct msg_buffers_chunk *chunk;
#ifndef _LP64
  int resvd;
#endif
  int refcnt;
  int magic;
  char data[0];
};

struct msg_buffers_chunk {
  int magic;
  int buffer_size;
  int (*free_buffer)(struct msg_buffers_chunk *C, struct msg_buffer *B);
  struct msg_buffers_chunk *ch_next, *ch_prev;
  struct msg_buffers_chunk *ch_head;
  struct msg_buffer *first_buffer;
  int two_power; /* least two-power >= tot_buffers */
  int tot_buffers;
  int bs_inverse;
  int bs_shift;
  struct mp_queue *free_block_queue;
  int thread_class;
  int thread_subclass;
  int refcnt;
  union {
    struct {
      int tot_chunks;
      int free_buffers;
    };
    unsigned short free_cnt[0];
  };
};

struct buffers_stat {
  long long total_used_buffers_size;
  long long allocated_buffer_bytes;
  long long buffer_chunk_alloc_ops;
  int total_used_buffers;
  int allocated_buffer_chunks, max_allocated_buffer_chunks, max_buffer_chunks;
  long long max_allocated_buffer_bytes; 
};

void fetch_buffers_stat (struct buffers_stat *bs);

int free_msg_buffer (struct msg_buffer *X);
static inline void msg_buffer_decref (struct msg_buffer *buffer) {
  if (buffer->refcnt == 1 || __sync_fetch_and_add (&buffer->refcnt, -1) == 1) {
    buffer->refcnt = 0;
    free_msg_buffer (buffer);
  }
}


int init_msg_buffers (long max_buffer_bytes);

struct msg_buffer *alloc_msg_buffer (struct msg_buffer *neighbor, int size_hint);

int free_msg_buffer (struct msg_buffer *buffer);
int msg_buffer_reach_limit (double ratio);
double msg_buffer_usage (void);

extern long long max_allocated_buffer_bytes; 
extern int allocated_buffer_chunks, max_allocated_buffer_chunks;