circ_buffer.c

/* Copyright Statement:
 *
 * This software/firmware and related documentation ("Fishsemi Software") are
 * protected under relevant copyright laws. The information contained herein is
 * confidential and proprietary to Fishsemi Inc. and/or its licensors. Without
 * the prior written permission of Fishsemi inc. and/or its licensors, any
 * reproduction, modification, use or disclosure of Fishsemi Software, and
 * information contained herein, in whole or in part, shall be strictly
 * prohibited.
 *
 * Fishsemi Inc. (C) 2019. All rights reserved.
 *
 * BY OPENING THIS FILE, RECEIVER HEREBY UNEQUIVOCALLY ACKNOWLEDGES AND AGREES
 * THAT THE SOFTWARE/FIRMWARE AND ITS DOCUMENTATIONS ("PINECONE SOFTWARE")
 * RECEIVED FROM PINECONE AND/OR ITS REPRESENTATIVES ARE PROVIDED TO RECEIVER
 * ON AN "AS-IS" BASIS ONLY. PINECONE EXPRESSLY DISCLAIMS ANY AND ALL
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 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
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 * SOFTWARE. PINECONE SHALL ALSO NOT BE RESPONSIBLE FOR ANY PINECONE SOFTWARE
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 * PINECONE SOFTWARE AT ISSUE, OR REFUND ANY SOFTWARE LICENSE FEES OR SERVICE
 * CHARGE PAID BY RECEIVER TO PINECONE FOR SUCH PINECONE SOFTWARE AT ISSUE.
 *
 * The following software/firmware and/or related documentation ("Fishsemi
 * Software") have been modified by Fishsemi Inc. All revisions are subject to
 * any receiver's applicable license agreements with Fishsemi Inc.
 */

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include "circ_buffer.h"
#include "utils.h"

/****************************************************************************
 * Private
 ****************************************************************************/

static inline size_t buffer_count(FAR struct cmgr_circ_buffer *buffer)
{
  return (buffer->head - buffer->tail) & (buffer->size - 1);
}

static inline size_t buffer_count_to_end(FAR struct cmgr_circ_buffer *buffer)
{
  size_t end = buffer->size - buffer->tail;
  size_t n = (buffer->head + end) & (buffer->size - 1);

  return n < end ? n : end;
}

static inline size_t buffer_space(FAR struct cmgr_circ_buffer *buffer)
{
  return (buffer->tail - buffer->head - 1) & (buffer->size - 1);
}

static inline size_t buffer_space_to_end(FAR struct cmgr_circ_buffer *buffer)
{
  size_t end = buffer->size - 1 - buffer->head;
  size_t n = (end + buffer->tail) & (buffer->size - 1);

  return n <= end ? n : (end + 1);
}

/****************************************************************************
 * Public
 ****************************************************************************/

int cmgr_circ_buffer_init(FAR struct cmgr_circ_buffer **buffer, FAR const char *name, size_t element_size, size_t size)
{
  FAR struct cmgr_circ_buffer *cb;

  if (size & (size - 1)) {
    snshuberr("circ buffer size is invalid of %s\n", name);
    return -EINVAL;
  }

  cb = calloc(1, sizeof(*cb) + element_size * size);
  if (!cb) {
    snshuberr("failed to malloc memory for circ buffer %s\n", name);
    return -ENOMEM;
  }

  cb->name = name;
  cb->element_size = element_size;
  cb->size = size;
  cb->data = cb + 1;

  *buffer = cb;

  return 0;
}

int cmgr_circ_buffer_push(FAR struct cmgr_circ_buffer *buffer, FAR void *data, int num)
{
  size_t space, num_to_write;
  size_t esize;

  space = buffer_space(buffer);
  if (num > space) {
    snshuberr("circ buffer: no enough space of %s\n", buffer->name);
    return -ENOMEM;
  }

  esize = buffer->element_size;
  space = buffer_space_to_end(buffer);
  num_to_write = (space >= num ? num : space);
  memcpy(buffer->data + buffer->head * esize, data, num_to_write * esize);

  num -= num_to_write;
  if (num > 0)
    memcpy(buffer->data, data + num_to_write * esize, num * esize);

  buffer->head = (buffer->head + num + num_to_write) & (buffer->size - 1);

  return 0;
}

/* return the actual element num got, otherwise a negative error */
int cmgr_circ_buffer_pop(FAR struct cmgr_circ_buffer *buffer, FAR void *data, int num)
{
  size_t cnt, num_to_read;
  size_t esize;

  esize = buffer->element_size;

  cnt = buffer_count(buffer);
  num = cnt > num ? num : cnt;

  cnt = buffer_count_to_end(buffer);
  num_to_read = cnt >= num ? num : cnt;
  memcpy(data, buffer->data + buffer->tail * esize, num_to_read * esize);

  num -= num_to_read;
  if (num > 0)
    memcpy(data + num_to_read * esize, buffer->data, num * esize);

  buffer->tail = (buffer->tail + num + num_to_read) & (buffer->size - 1);

  return num + num_to_read;
}

/* the return value is the count of handled elements, or negetive error N.O. */
int cmgr_circ_buffer_for_each(FAR struct cmgr_circ_buffer *buffer, buffer_handler handler)
{
  size_t cnt, i;
  FAR void *element;
  size_t esize;

  if (!handler)
    return -EINVAL;

  esize = buffer->element_size;

  cnt = buffer_count(buffer);
  for (i = 0; i < cnt; i++) {
    element = buffer->data + ((buffer->tail + i) & (buffer->size - 1)) * esize;
    handler(element);
  }

  buffer->tail = (buffer->tail + cnt) & (buffer->size - 1);

  return cnt;
}

void cmgr_circ_buffer_deinit(FAR struct cmgr_circ_buffer *buffer)
{
  free(buffer);
}