text: /**
   * Copyright (c) 2017 - 2018, Nordic Semiconductor ASA
   * 
   * All rights reserved.
   * 
   * Redistribution and use in source and binary forms, with or without modification,
   * are permitted provided that the following conditions are met:
   * 
   * 1. Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   * 
   * 2. Redistributions in binary form, except as embedded into a Nordic
   *    Semiconductor ASA integrated circuit in a product or a software update for
   *    such product, must reproduce the above copyright notice, this list of
   *    conditions and the following disclaimer in the documentation and/or other
   *    materials provided with the distribution.
   * 
   * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
   *    contributors may be used to endorse or promote products derived from this
   *    software without specific prior written permission.
   * 
   * 4. This software, with or without modification, must only be used with a
   *    Nordic Semiconductor ASA integrated circuit.
   * 
   * 5. Any software provided in binary form under this license must not be reverse
   *    engineered, decompiled, modified and/or disassembled.
   * 
   * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
   * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
   * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   * 
   */
  
  #include "nrf_memobj.h"
  #include "nrf_atomic.h"
  #include "nrf_assert.h"
  
  typedef struct memobj_elem_s memobj_elem_t;
  
  typedef struct
  {
      memobj_elem_t * p_next;
  } memobj_header_t;
  
  typedef struct
  {
      uint8_t  user_cnt;
      uint8_t  chunk_cnt;
      uint16_t chunk_size;
  } memobj_head_header_fields_t;
  
  typedef struct
  {
      union
      {
          nrf_atomic_u32_t            atomic_user_cnt;
          memobj_head_header_fields_t fields;
      } data;
  } memobj_head_header_t;
  
  typedef struct
  {
      memobj_header_t      header;
      memobj_head_header_t head_header;
      uint8_t              data[1];
  } memobj_head_t;
  
  STATIC_ASSERT(sizeof(memobj_header_t) == NRF_MEMOBJ_STD_HEADER_SIZE);
  
  struct memobj_elem_s
  {
      memobj_header_t  header;
      uint8_t          data[1];
  };
  
  ret_code_t nrf_memobj_pool_init(nrf_memobj_pool_t const * p_pool)
  {
      return nrf_balloc_init((nrf_balloc_t const *)p_pool);
  }
  
  nrf_memobj_t * nrf_memobj_alloc(nrf_memobj_pool_t const * p_pool,
                                  size_t size)
  {
      uint32_t bsize = (uint32_t)NRF_BALLOC_ELEMENT_SIZE((nrf_balloc_t const *)p_pool) - sizeof(memobj_header_t);
      uint8_t num_of_chunks = (uint8_t)CEIL_DIV(size + sizeof(memobj_head_header_t), bsize);
  
      memobj_head_t * p_head = nrf_balloc_alloc((nrf_balloc_t const *)p_pool);
      if (p_head == NULL)
      {
          return NULL;
      }
      p_head->head_header.data.fields.user_cnt = 0;
      p_head->head_header.data.fields.chunk_cnt = 1;
      p_head->head_header.data.fields.chunk_size = bsize;
  
      memobj_header_t * p_prev = (memobj_header_t *)p_head;
      memobj_header_t * p_curr;
      uint32_t i;
      uint32_t chunk_less1 = (uint32_t)num_of_chunks - 1;
  
      p_prev->p_next =  (memobj_elem_t *)p_pool;
      for (i = 0; i < chunk_less1; i++)
      {
          p_curr = (memobj_header_t *)nrf_balloc_alloc((nrf_balloc_t const *)p_pool);
          if (p_curr)
          {
              (p_head->head_header.data.fields.chunk_cnt)++;
              p_prev->p_next = (memobj_elem_t *)p_curr;
              p_curr->p_next = (memobj_elem_t *)p_pool;
              p_prev = p_curr;
          }
          else
          {
              //Couldn't allocate all requested buffers
              nrf_memobj_free((nrf_memobj_t *)p_head);
              return NULL;
          }
      }
      return (nrf_memobj_t *)p_head;
  }
  
  void nrf_memobj_free(nrf_memobj_t * p_obj)
  {
      memobj_head_t * p_head = (memobj_head_t *)p_obj;
      uint8_t chunk_cnt = p_head->head_header.data.fields.chunk_cnt;
      uint32_t i;
      memobj_header_t * p_curr = (memobj_header_t *)p_obj;
      memobj_header_t * p_next;
      uint32_t chunk_less1 = (uint32_t)chunk_cnt - 1;
  
      for (i = 0; i < chunk_less1; i++)
      {
          p_curr = (memobj_header_t *)p_curr->p_next;
      }
      nrf_balloc_t const * p_pool2 = (nrf_balloc_t const *)p_curr->p_next;
  
      p_curr = (memobj_header_t *)p_obj;
      for (i = 0; i < chunk_cnt; i++)
      {
          p_next = (memobj_header_t *)p_curr->p_next;
          nrf_balloc_free(p_pool2, p_curr);
          p_curr = p_next;
      }
  }
  
  void nrf_memobj_get(nrf_memobj_t const * p_obj)
  {
      memobj_head_t * p_head = (memobj_head_t *)p_obj;
      (void)nrf_atomic_u32_add(&p_head->head_header.data.atomic_user_cnt, 1);
  }
  
  void nrf_memobj_put(nrf_memobj_t * p_obj)
  {
      memobj_head_t * p_head = (memobj_head_t *)p_obj;
      uint32_t user_cnt = nrf_atomic_u32_sub(&p_head->head_header.data.atomic_user_cnt, 1);
      memobj_head_header_fields_t * p_fields = (memobj_head_header_fields_t *)&user_cnt;
      if (p_fields->user_cnt == 0)
      {
          nrf_memobj_free(p_obj);
      }
  }
  
  static void memobj_op(nrf_memobj_t * p_obj,
                        void * p_data,
                        uint32_t len,
                        uint32_t offset,
                        bool read)
  {
  
      memobj_head_t * p_head  = (memobj_head_t *)p_obj;
      uint32_t space_in_chunk = p_head->head_header.data.fields.chunk_size;
      memobj_elem_t * p_curr_chunk = (memobj_elem_t *)p_obj;
      uint32_t chunk_idx = (offset + sizeof(memobj_head_header_fields_t))/space_in_chunk;
      uint32_t chunk_offset = (offset + sizeof(memobj_head_header_fields_t)) % space_in_chunk;
  
      uint8_t chunks_expected = CEIL_DIV((offset + sizeof(memobj_head_header_fields_t) + len),
                                         space_in_chunk);
      UNUSED_VARIABLE(chunks_expected);
      ASSERT(p_head->head_header.data.fields.chunk_cnt >= chunks_expected);
  
      while (chunk_idx > 0)
      {
          p_curr_chunk = p_curr_chunk->header.p_next;
          chunk_idx--;
      }
  
      uint32_t src_offset  = 0;
      uint32_t curr_cpy_size = space_in_chunk-chunk_offset;
      curr_cpy_size = curr_cpy_size > len ? len : curr_cpy_size;
  
      while (len)
      {
          if (read)
          {
              memcpy(&((uint8_t *)p_data)[src_offset], &p_curr_chunk->data[chunk_offset], curr_cpy_size);
          }
          else
          {
              memcpy(&p_curr_chunk->data[chunk_offset], &((uint8_t *)p_data)[src_offset], curr_cpy_size);
          }
          chunk_offset = 0;
          p_curr_chunk = p_curr_chunk->header.p_next;
          len -= curr_cpy_size;
          src_offset += curr_cpy_size;
          curr_cpy_size = (space_in_chunk > len) ? len : space_in_chunk;
      }
  }
  
  void nrf_memobj_write(nrf_memobj_t * p_obj,
                        void * p_data,
                        uint32_t len,
                        uint32_t offset)
  {
  
      memobj_op(p_obj, p_data, len, offset, false);
  }
  
  void nrf_memobj_read(nrf_memobj_t * p_obj,
                       void * p_data,
                       uint32_t len,
                       uint32_t offset)
  {
      memobj_op(p_obj, p_data, len, offset, true);
  }
  