/*
 * Copyright 2013-2019 Software Radio Systems Limited
 *
 * This file is part of srsLTE.
 *
 * srsLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * srsLTE 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 Affero General Public License for more details.
 *
 * A copy of the GNU Affero General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */

#ifndef SRSLTE_COMMON_H
#define SRSLTE_COMMON_H

/*******************************************************************************
                              INCLUDES
*******************************************************************************/

#include <memory>
#include <stdint.h>
#include <string.h>

/*******************************************************************************
                              DEFINES
*******************************************************************************/

#define SRSLTE_UE_CATEGORY     4

#define SRSLTE_N_SRB           3
#define SRSLTE_N_DRB           8
#define SRSLTE_N_RADIO_BEARERS 11

#define SRSLTE_N_MCH_LCIDS     32

#define TX_DELAY 4
#define MSG3_DELAY_MS 2 // Delay added to TX_DELAY

#define TTI_SUB(a, b) ((((a) + 10240) - (b)) % 10240)

#define TTI_TX(tti) ((tti + TX_DELAY) % 10240)

// Use only in FDD mode!!
#define FDD_HARQ_DELAY_MS 4
#define TTI_RX(tti) (TTI_SUB(tti, FDD_HARQ_DELAY_MS))
#define TTI_RX_ACK(tti) ((tti + (2 * FDD_HARQ_DELAY_MS)) % 10240)

#define TTIMOD_SZ 20
#define TTIMOD(tti)     (tti%TTIMOD_SZ)

#define PHICH_MAX_SF 6 // Maximum PHICH in a subframe (1 in FDD, > 1 in TDD, see table 9.1.2-1 36.213)

#define ASYNC_DL_SCHED (FDD_HARQ_DELAY_MS <= 4)

// Cat 4 UE - Max number of DL-SCH transport block bits received within a TTI
// 3GPP 36.306 Table 4.1.1
#define SRSLTE_MAX_BUFFER_SIZE_BITS  150752
#define SRSLTE_MAX_BUFFER_SIZE_BYTES (SRSLTE_MAX_BUFFER_SIZE_BITS/8)
#define SRSLTE_BUFFER_HEADER_OFFSET  1020

//#define SRSLTE_BUFFER_POOL_LOG_ENABLED

#ifdef SRSLTE_BUFFER_POOL_LOG_ENABLED
#define pool_allocate (srslte::allocate_unique_buffer(*pool, __PRETTY_FUNCTION__))
#define pool_allocate_blocking (srslte::allocate_unique_buffer(*pool, __PRETTY_FUNCTION__, true))
#define SRSLTE_BUFFER_POOL_LOG_NAME_LEN 128
#else
#define pool_allocate (srslte::allocate_unique_buffer(*pool))
#define pool_allocate_blocking (srslte::allocate_unique_buffer(*pool, true))
#endif

#include "srslte/srslte.h"

/*******************************************************************************
                              TYPEDEFS
*******************************************************************************/

namespace srslte {

//#define ENABLE_TIMESTAMP

/******************************************************************************
 * Byte and Bit buffers
 *
 * Generic buffers with headroom to accommodate packet headers and custom
 * copy constructors & assignment operators for quick copying. Byte buffer
 * holds a next pointer to support linked lists.
 *****************************************************************************/
class byte_buffer_t{
public:
    uint32_t    N_bytes;
    uint8_t     buffer[SRSLTE_MAX_BUFFER_SIZE_BYTES];
    uint8_t    *msg;
#ifdef SRSLTE_BUFFER_POOL_LOG_ENABLED
    char        debug_name[SRSLTE_BUFFER_POOL_LOG_NAME_LEN];
#endif

    byte_buffer_t():N_bytes(0)
    {
      bzero(buffer, SRSLTE_MAX_BUFFER_SIZE_BYTES);
#ifdef ENABLE_TIMESTAMP
      timestamp_is_set = false;
#endif
      msg = &buffer[SRSLTE_BUFFER_HEADER_OFFSET];
      next = NULL; 
#ifdef SRSLTE_BUFFER_POOL_LOG_ENABLED
      bzero(debug_name, SRSLTE_BUFFER_POOL_LOG_NAME_LEN);
#endif
    }
    byte_buffer_t(const byte_buffer_t& buf)
    {
      bzero(buffer, SRSLTE_MAX_BUFFER_SIZE_BYTES);
      msg = &buffer[SRSLTE_BUFFER_HEADER_OFFSET];
      next = NULL;
      // copy actual contents
      N_bytes = buf.N_bytes;
      memcpy(msg, buf.msg, N_bytes);
    }
    byte_buffer_t & operator= (const byte_buffer_t & buf)
    {
      // avoid self assignment
      if (&buf == this)
        return *this;
      bzero(buffer, SRSLTE_MAX_BUFFER_SIZE_BYTES);
      msg = &buffer[SRSLTE_BUFFER_HEADER_OFFSET];
      next = NULL;
      N_bytes = buf.N_bytes;
      memcpy(msg, buf.msg, N_bytes);
      return *this;
    }
    void clear()
    {
      msg       = &buffer[SRSLTE_BUFFER_HEADER_OFFSET];
      N_bytes   = 0;
#ifdef ENABLE_TIMESTAMP
      timestamp_is_set = false;
#endif
    }
    uint32_t get_headroom()
    {
      return msg-buffer;
    }
    // Returns the remaining space from what is reported to be the length of msg
    uint32_t get_tailroom()
    {
      return (sizeof(buffer) - (msg-buffer) - N_bytes);
    }
    long get_latency_us()
    {
#ifdef ENABLE_TIMESTAMP
      if(!timestamp_is_set)
        return 0;
      gettimeofday(&timestamp[2], NULL); 
      get_time_interval(timestamp);
      return timestamp[0].tv_usec;
#else
      return 0;
#endif
    }
    
    void set_timestamp() 
    {
#ifdef ENABLE_TIMESTAMP
      gettimeofday(&timestamp[1], NULL);
      timestamp_is_set = true;
#endif
    }

  private:
#ifdef ENABLE_TIMESTAMP
    struct timeval timestamp[3];
    bool           timestamp_is_set; 
#endif
    byte_buffer_t *next;
};

struct bit_buffer_t{
    uint32_t    N_bits;
    uint8_t     buffer[SRSLTE_MAX_BUFFER_SIZE_BITS];
    uint8_t    *msg;
#ifdef SRSLTE_BUFFER_POOL_LOG_ENABLED
    char        debug_name[128];
#endif

    bit_buffer_t():N_bits(0)
    {
      msg = &buffer[SRSLTE_BUFFER_HEADER_OFFSET];
#ifdef ENABLE_TIMESTAMP
      timestamp_is_set = false;
#endif
    }
    bit_buffer_t(const bit_buffer_t& buf){
      msg = &buffer[SRSLTE_BUFFER_HEADER_OFFSET];
      N_bits = buf.N_bits;
      memcpy(msg, buf.msg, N_bits);
    }
    bit_buffer_t & operator= (const bit_buffer_t & buf){
      // avoid self assignment
      if (&buf == this) {
        return *this;
      }
      msg = &buffer[SRSLTE_BUFFER_HEADER_OFFSET];
      N_bits = buf.N_bits;
      memcpy(msg, buf.msg, N_bits);
      return *this;
    }
    void clear()
    {
      msg       = &buffer[SRSLTE_BUFFER_HEADER_OFFSET];
      N_bits    = 0;
#ifdef ENABLE_TIMESTAMP
      timestamp_is_set = false;
#endif
    }
    uint32_t get_headroom()
    {
      return msg-buffer;
    }
    long get_latency_us()
    {
#ifdef ENABLE_TIMESTAMP
      if(!timestamp_is_set)
        return 0;
      gettimeofday(&timestamp[2], NULL); 
      return timestamp[0].tv_usec;
#else
      return 0;
#endif
    }
    void set_timestamp() 
    {
#ifdef ENABLE_TIMESTAMP
      gettimeofday(&timestamp[1], NULL);
      timestamp_is_set = true;
#endif
    }

private:
#ifdef ENABLE_TIMESTAMP
    struct timeval timestamp[3];
    bool           timestamp_is_set; 
#endif
};

// Create a Managed Life-Time Byte Buffer
class byte_buffer_pool;
class byte_buffer_deleter
{
public:
  explicit byte_buffer_deleter(byte_buffer_pool* pool_ = nullptr) : pool(pool_) {}
  void              operator()(byte_buffer_t* buf) const;
  byte_buffer_pool* pool;
};

typedef std::unique_ptr<byte_buffer_t, byte_buffer_deleter> unique_byte_buffer_t;

} // namespace srslte

#endif // SRSLTE_COMMON_H