/******************************************************************************
 *
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *****************************************************************************
 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
*/
/**
*******************************************************************************
* @file
*  ih264_list.c
*
* @brief
*  Contains functions for buf queue
*
* @author
*  Harish
*
* @par List of Functions:
*  ih264_list_size()
*  ih264_list_lock()
*  ih264_list_unlock()
*  ih264_list_yield()
*  ih264_list_free()
*  ih264_list_init()
*  ih264_list_reset()
*  ih264_list_deinit()
*  ih264_list_terminate()
*  ih264_list_queue()
*  ih264_list_dequeue()
*
* @remarks
*  None
*
*******************************************************************************
*/
/*****************************************************************************/
/* File Includes                                                             */
/*****************************************************************************/
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include "ih264_typedefs.h"
#include "ithread.h"
#include "ih264_platform_macros.h"
#include "ih264_macros.h"
#include "ih264_debug.h"
#include "ih264_error.h"
#include "ih264_list.h"

/**
*******************************************************************************
*
* @brief Returns size for buf queue context. Does not include buf queue buffer
* requirements
*
* @par   Description
* Returns size for buf queue context. Does not include buf queue buffer
* requirements. Buffer size required to store the bufs should be allocated in
* addition to the value returned here.
*
* @returns Size of the buf queue context
*
* @remarks
*
*******************************************************************************
*/
WORD32 ih264_list_size(WORD32 num_entries, WORD32 entry_size)
{
    WORD32 size;
    WORD32 clz;
    size = sizeof(list_t);
    size += ithread_get_mutex_lock_size();

    /* Use next power of two number of entries*/
    clz = CLZ(num_entries);
    num_entries = 1 << (32 - clz);

    size  += num_entries * entry_size;
    return size;
}

/**
*******************************************************************************
*
* @brief
*   Locks the list context
*
* @par   Description
*   Locks the list context by calling ithread_mutex_lock()
*
* @param[in] ps_list
*   Job Queue context
*
* @returns IH264_FAIL if mutex lock fails else IH264_SUCCESS
*
* @remarks
*
*******************************************************************************
*/
IH264_ERROR_T ih264_list_lock(list_t *ps_list)
{
    WORD32 retval;
    retval = ithread_mutex_lock(ps_list->pv_mutex);
    if(retval)
    {
        return IH264_FAIL;
    }
    return IH264_SUCCESS;
}

/**
*******************************************************************************
*
* @brief
*   Unlocks the list context
*
* @par   Description
*   Unlocks the list context by calling ithread_mutex_unlock()
*
* @param[in] ps_list
*   Job Queue context
*
* @returns IH264_FAIL if mutex unlock fails else IH264_SUCCESS
*
* @remarks
*
*******************************************************************************
*/

IH264_ERROR_T ih264_list_unlock(list_t *ps_list)
{
    WORD32 retval;
    retval = ithread_mutex_unlock(ps_list->pv_mutex);
    if(retval)
    {
        return IH264_FAIL;
    }
    return IH264_SUCCESS;

}
/**
*******************************************************************************
*
* @brief
*   Yields the thread
*
* @par   Description
*   Unlocks the list context by calling
* ih264_list_unlock(), ithread_yield() and then ih264_list_lock()
* list is unlocked before to ensure the list can be accessed by other threads
* If unlock is not done before calling yield then no other thread can access
* the list functions and update list.
*
* @param[in] ps_list
*   Job Queue context
*
* @returns IH264_FAIL if mutex lock unlock or yield fails else IH264_SUCCESS
*
* @remarks
*
*******************************************************************************
*/
IH264_ERROR_T ih264_list_yield(list_t *ps_list)
{

    IH264_ERROR_T ret = IH264_SUCCESS;

    IH264_ERROR_T rettmp;
    rettmp = ih264_list_unlock(ps_list);
    RETURN_IF((rettmp != IH264_SUCCESS), rettmp);

    ithread_yield();

    if(ps_list->i4_yeild_interval_us > 0)
        ithread_usleep(ps_list->i4_yeild_interval_us);

    rettmp = ih264_list_lock(ps_list);
    RETURN_IF((rettmp != IH264_SUCCESS), rettmp);
    return ret;
}


/**
*******************************************************************************
*
* @brief free the buf queue pointers
*
* @par   Description
* Frees the list context
*
* @param[in] pv_buf
* Memory for buf queue buffer and buf queue context
*
* @returns Pointer to buf queue context
*
* @remarks
* Since it will be called only once by master thread this is not thread safe.
*
*******************************************************************************
*/
IH264_ERROR_T ih264_list_free(list_t *ps_list)
{
    WORD32 ret;
    ret = ithread_mutex_destroy(ps_list->pv_mutex);

    if(0 == ret)
        return IH264_SUCCESS;
    else
        return IH264_FAIL;
}

/**
*******************************************************************************
*
* @brief Initialize the buf queue
*
* @par   Description
* Initializes the list context and sets write and read pointers to start of
* buf queue buffer
*
* @param[in] pv_buf
* Memoy for buf queue buffer and buf queue context
*
* @param[in] buf_size
* Size of the total memory allocated
*
* @returns Pointer to buf queue context
*
* @remarks
* Since it will be called only once by master thread this is not thread safe.
*
*******************************************************************************
*/
void* ih264_list_init(void *pv_buf,
                      WORD32 buf_size,
                      WORD32 num_entries,
                      WORD32 entry_size,
                      WORD32 yeild_interval_us)
{
    list_t *ps_list;
    UWORD8 *pu1_buf;

    pu1_buf = (UWORD8 *)pv_buf;

    ps_list = (list_t *)pu1_buf;
    pu1_buf += sizeof(list_t);
    buf_size -= sizeof(list_t);

    ps_list->pv_mutex = pu1_buf;
    pu1_buf += ithread_get_mutex_lock_size();
    buf_size -= ithread_get_mutex_lock_size();

    if (buf_size <= 0)
      return NULL;

    ithread_mutex_init(ps_list->pv_mutex);

    /* Ensure num_entries is power of two */
    ASSERT(0 == (num_entries & (num_entries - 1)));

    /* Ensure remaining buffer is large enough to hold given number of entries */
    ASSERT((num_entries * entry_size) <= buf_size);

    ps_list->pv_buf_base = pu1_buf;
    ps_list->i4_terminate = 0;
    ps_list->i4_entry_size = entry_size;
    ps_list->i4_buf_rd_idx = 0;
    ps_list->i4_buf_wr_idx = 0;
    ps_list->i4_log2_buf_max_idx = 32 - CLZ(num_entries);
    ps_list->i4_buf_max_idx = num_entries;
    ps_list->i4_yeild_interval_us = yeild_interval_us;

    return ps_list;
}
/**
*******************************************************************************
*
* @brief
*   Resets the list context
*
* @par   Description
*   Resets the list context by initializing buf queue context elements
*
* @param[in] ps_list
*   Job Queue context
*
* @returns IH264_FAIL if lock unlock fails else IH264_SUCCESS
*
* @remarks
*
*******************************************************************************
*/
IH264_ERROR_T ih264_list_reset(list_t *ps_list)
{
    IH264_ERROR_T ret = IH264_SUCCESS;
    ret = ih264_list_lock(ps_list);
    RETURN_IF((ret != IH264_SUCCESS), ret);

    ps_list->i4_terminate  = 0;
    ps_list->i4_buf_rd_idx = 0;
    ps_list->i4_buf_wr_idx = 0;

    ret = ih264_list_unlock(ps_list);
    RETURN_IF((ret != IH264_SUCCESS), ret);

    return ret;
}

/**
*******************************************************************************
*
* @brief
*   Deinitializes the list context
*
* @par   Description
*   Deinitializes the list context by calling ih264_list_reset()
* and then destrying the mutex created
*
* @param[in] ps_list
*   Job Queue context
*
* @returns IH264_FAIL if lock unlock fails else IH264_SUCCESS
*
* @remarks
*
*******************************************************************************
*/
IH264_ERROR_T ih264_list_deinit(list_t *ps_list)
{
    WORD32 retval;
    IH264_ERROR_T ret = IH264_SUCCESS;

    ret = ih264_list_reset(ps_list);
    RETURN_IF((ret != IH264_SUCCESS), ret);

    retval = ithread_mutex_destroy(ps_list->pv_mutex);
    if(retval)
    {
        return IH264_FAIL;
    }

    return IH264_SUCCESS;
}


/**
*******************************************************************************
*
* @brief
*   Terminates the list
*
* @par   Description
*   Terminates the list by setting a flag in context.
*
* @param[in] ps_list
*   Job Queue context
*
* @returns IH264_FAIL if lock unlock fails else IH264_SUCCESS
*
* @remarks
*
*******************************************************************************
*/

IH264_ERROR_T ih264_list_terminate(list_t *ps_list)
{
    IH264_ERROR_T ret = IH264_SUCCESS;
    ret = ih264_list_lock(ps_list);
    RETURN_IF((ret != IH264_SUCCESS), ret);

    ps_list->i4_terminate = 1;

    ret = ih264_list_unlock(ps_list);
    RETURN_IF((ret != IH264_SUCCESS), ret);
    return ret;
}


/**
*******************************************************************************
*
* @brief Adds a buf to the queue
*
* @par   Description
* Adds a buf to the queue and updates wr address to next location.
* Format/content of the buf structure is abstracted and hence size of the buf
* buffer is being passed.
*
* @param[in] ps_list
*   Job Queue context
*
* @param[in] pv_buf
*   Pointer to the location that contains details of the buf to be added
*
* @param[in] buf_size
*   Size of the buf buffer
*
* @param[in] blocking
*   To signal if the write is blocking or non-blocking.
*
* @returns
*
* @remarks
* Job Queue buffer is assumed to be allocated to handle worst case number of bufs
* Wrap around is not supported
*
*******************************************************************************
*/
IH264_ERROR_T ih264_list_queue(list_t *ps_list, void *pv_buf, WORD32 blocking)
{
    IH264_ERROR_T ret = IH264_SUCCESS;
    IH264_ERROR_T rettmp;

    WORD32 diff;
    void *pv_buf_wr;

    volatile WORD32 *pi4_wr_idx, *pi4_rd_idx;
    WORD32 buf_size = ps_list->i4_entry_size;


    rettmp = ih264_list_lock(ps_list);
    RETURN_IF((rettmp != IH264_SUCCESS), rettmp);


    while(1)
    {
        /* Ensure wr idx does not go beyond rd idx by more than number of entries
         */
        pi4_wr_idx = &ps_list->i4_buf_wr_idx;
        pi4_rd_idx = &ps_list->i4_buf_rd_idx;
        diff = *pi4_wr_idx - *pi4_rd_idx;

        if(diff < ps_list->i4_buf_max_idx)
        {
            WORD32 wr_idx;
            wr_idx = ps_list->i4_buf_wr_idx & (ps_list->i4_buf_max_idx - 1);
            pv_buf_wr = (UWORD8 *)ps_list->pv_buf_base + wr_idx * buf_size;

            memcpy(pv_buf_wr, pv_buf, buf_size);
            ps_list->i4_buf_wr_idx++;
            break;
        }
        else
        {
            /* wr is ahead, so wait for rd to consume */
            if(blocking)
            {
                ih264_list_yield(ps_list);
            }
            else
            {
                ret = IH264_FAIL;
                break;
            }
        }

    }
    ps_list->i4_terminate = 0;

    rettmp = ih264_list_unlock(ps_list);
    RETURN_IF((rettmp != IH264_SUCCESS), rettmp);

    return ret;
}
/**
*******************************************************************************
*
* @brief Gets next from the Job queue
*
* @par   Description
* Gets next buf from the buf queue and updates rd address to next location.
* Format/content of the buf structure is abstracted and hence size of the buf
* buffer is being passed. If it is a blocking call and if there is no new buf
* then this functions unlocks the mutex and calls yield and then locks it back.
* and continues till a buf is available or terminate is set
*
* @param[in] ps_list
*   Job Queue context
*
* @param[out] pv_buf
*   Pointer to the location that contains details of the buf to be written
*
* @param[in] buf_size
*   Size of the buf buffer
*
* @param[in] blocking
*   To signal if the read is blocking or non-blocking.
*
* @returns
*
* @remarks
* Job Queue buffer is assumed to be allocated to handle worst case number of bufs
* Wrap around is not supported
*
*******************************************************************************
*/
IH264_ERROR_T ih264_list_dequeue(list_t *ps_list, void *pv_buf, WORD32 blocking)
{
    IH264_ERROR_T ret = IH264_SUCCESS;
    IH264_ERROR_T rettmp;
    WORD32 buf_size = ps_list->i4_entry_size;
    WORD32 diff;

    void *pv_buf_rd;
    volatile WORD32 *pi4_wr_idx, *pi4_rd_idx;

    rettmp = ih264_list_lock(ps_list);
    RETURN_IF((rettmp != IH264_SUCCESS), rettmp);

    while(1)
    {
        /* Ensure wr idx is ahead of rd idx and
         * wr idx does not go beyond rd idx by more than number of entries
         */
        pi4_wr_idx = &ps_list->i4_buf_wr_idx;
        pi4_rd_idx = &ps_list->i4_buf_rd_idx;
        diff = *pi4_wr_idx - *pi4_rd_idx;


        if(diff > 0)
        {
            WORD32 rd_idx;
            rd_idx = ps_list->i4_buf_rd_idx & (ps_list->i4_buf_max_idx - 1);
            pv_buf_rd = (UWORD8 *)ps_list->pv_buf_base + rd_idx * buf_size;

            memcpy(pv_buf, pv_buf_rd, buf_size);
            ps_list->i4_buf_rd_idx++;
            break;
        }
        else
        {
            /* If terminate is signaled then break */
            if(ps_list->i4_terminate)
            {
                ret = IH264_FAIL;
                break;
            }
            /* wr is ahead, so wait for rd to consume */
            if(blocking)
            {
                ih264_list_yield(ps_list);
            }
            else
            {
                ret = IH264_FAIL;
                break;
            }
        }

    }


    rettmp = ih264_list_unlock(ps_list);
    RETURN_IF((rettmp != IH264_SUCCESS), rettmp);

    return ret;
}