pipe.c

Bycore是一个嵌入式操作系统内核。Bycore包括内存管理、任务管理、中断管理、任务互斥、同步与通信管理等功能。Bycore全部由C语言完成

/**
 *  pipe.c - Related routines of pipe.
 *
 *  Copyright (C) 2008  ZhangHu
 *  All rights reserved.
 *  E-MAIL: [e-mail]
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "include/types.h"
#include "include/core.h"
#include "include/mem.h"
#include "include/pipe.h"
#include "include/sem.h"
#include "include/irq.h"


/**
 * pipeInit - It creates a new pipe.
 * @SendID: ID of task that sends data to pipe.
 * @RevID: ID of task that receives data from pipe.
 * @Size: The size of pipe.
 * @return: The start address of new pipe.
 *
 * @notes:
 */
pipe_t *pipeInit(uword_t SendID, uword_t RevID, uword_t Size) {
    pipe_t *pipe;
    void **ptmp;

    if((pipe = (pipe_t*)kmalloc(sizeof(pipe_t))) == NULL) {
        return NULL;
    }

    if((ptmp = (void **)kmalloc(Size *sizeof(void*))) == NULL) {
        kfree(pipe);
        return NULL;
    }

    pipe->in = ptmp;
    pipe->out = ptmp;
    pipe->start = ptmp;
    pipe->end = &ptmp[Size - 1];
    pipe->send_id = SendID;
    pipe->rev_id = RevID;
    pipe->size = Size;
    pipe->used = 0;
    return pipe;
}

/**
 * pipeSend - Sending a message to a pipe.
 * @pPipe: Pointer to the pipe.
 * @pMsg: Pointer to the message.
 * @err: It will return rusults or reasons about operation.
 * @return: TURE if successful, otherwise FALSE;
 *
 * @notes:
 */
uword_t pipeSend(pipe_t *pPipe, void *pMsg, uword_t *err) {
    if(pPipe == NULL) {
        *err = PIPE_ID_NOT_MATCH;
        return FALSE;
    }

    if(current()->id != pPipe->send_id) {
        *err = PIPE_ID_NOT_MATCH;
        return FALSE;
    }

    mac_disable_irq();
    if(pPipe->size == pPipe->used) {
        *err = PIPE_FULL;
        mac_enable_irq();
        return FALSE;
    }

    *pPipe->in = pMsg;
    if(pPipe->in++ == pPipe->end) {
        pPipe->in = pPipe->start;
    }
    pPipe->used++;
    *err = PIPE_OK;
    mac_enable_irq();
    return TRUE;
}

/**
 * pipeRev - Retrieve message from pipe.
 * @pPipe: Pointer to the pipe.
 * @err: It will return rusults or reasons of this operation.
 * @return: The message if successful, NULL for failed.
 *
 * @notes:
 */
void *pipeRev(pipe_t *pPipe, uword_t *err) {
    void **pmsg;

    if(pPipe == NULL) {
        *err = PIPE_ID_NOT_MATCH;
        return NULL;
    }

    if(current()->id != pPipe->rev_id) {
        *err = PIPE_ID_NOT_MATCH;
        return NULL;
    }

    mac_disable_irq();

    if(pPipe->used == 0) {
        *err = PIPE_EMPTY;
        mac_enable_irq();
        return NULL;
    }

    pmsg = pPipe->out;
    pPipe->used--;
    if(pPipe->out++ == pPipe->end) {
        pPipe->out = pPipe->start;
    }
    *err = PIPE_OK;
    mac_enable_irq();
    return  *pmsg;
}

/**
 * pipeClear - Clear a pipe.
 * @pPipe: Pointer to the pipe.
 * @return:
 *
 * @notes:
 */
void pipeClear(pipe_t *pPipe) {
    pPipe->used = 0;
    pPipe->in = pPipe->start;
    pPipe->out = pPipe->start;
}

/**
 * pipeDel - Delete a pipe.
 * @pPipe: Pointer to the pipe.
 * @return:
 *
 * @notes:
 */
void pipeDel(pipe_t *pPipe) {
    kfree(pPipe);
}