/************************************************************  Copyright (C), 2007,DTK Computer.  FileName: key_buffer.c  Author:   rome              Version : 1.0.0         Date:2007.03.21  Description:     鍵盤(pán)緩沖操作，在內(nèi)部處理了競(jìng)爭(zhēng)條件的情況。        Version:         DTK-EMMI-1.0.0  Function List:       1.key_buffer_new:鍵盤(pán)緩沖對(duì)象的創(chuàng)建。    2.key_buffer_clear:清除鍵盤(pán)緩沖內(nèi)容。    3.key_buffer_is_empty:緩沖對(duì)象內(nèi)部沒(méi)有加鎖的情況下判斷緩沖是否為空。    4.key_buffer_is_empty_unlock:緩沖對(duì)象內(nèi)部加鎖的情況下判斷緩沖是否為空。     5.key_buffer_put:把掃描碼放進(jìn)緩沖。    6.key_buffer_get:從緩沖獲取掃描碼，超時(shí)返回超時(shí)碼。  Macro List:    1.key_buffer_cycle_add:在 0到(KEY_BUFFER_LEN-1)的取值范圍內(nèi)循環(huán)加。    2.TRACE(x...):用于測(cè)試打印調(diào)試信息。  History:               <author>   <time>    <version >    <desc>      rome      2007/03/21  1.0.0     build this moudle  ***********************************************************/#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <time.h>#include <sys/time.h>#include <assert.h>#include "key_buffer.h"#include "mmi_lock.h"//#define KEY_BUFFER_LEN 16#define KEY_BUFFER_LEN 8 /* for test the simulate *//* 通過(guò) ＆ 操作符使KeyBuffer中的index值的取值范圍為: 0---KEY_BUFFER_LEN - 1    注意KEY_BUFFER_LEN必需是 2 的 n 次方 */#define key_buffer_cycle_add(index)                   \         do                                           \         {                                            \          (index) = ((index) + 1) & (KEY_BUFFER_LEN - 1); \         } while(0)/* 下面的宏是測(cè)試用的 */#define KEY_BUFFER_TEST 1#ifdef KEY_BUFFER_TEST    #define TRACE(x...)    printf("KeyBuffer: " x)#else    #define TRACE(x...)   do {} while(0)#endifstruct _KeyBuffer{    mmi_mutex_t lock;    mmi_thread_cond_t cond;    D_INT8 waiter;    D_INT8 head;    D_INT8 tail;    char buf[KEY_BUFFER_LEN];};KeyBuffer *key_buffer_new(void){    KeyBuffer *key_buffer;    key_buffer = (KeyBuffer *)calloc(1, sizeof(struct _KeyBuffer));    key_buffer->head = key_buffer->tail = 0;    key_buffer->waiter = 0;    mmi_mutext_init(&key_buffer->lock, NULL);    mmi_thread_cond_init(&key_buffer->cond, NULL);    return key_buffer;}void key_buffer_destroy(KeyBuffer *key_buffer){    mmi_mutext_destroy(&key_buffer->lock);    mmi_thread_cond_destroy(&key_buffer->cond);        //memset(key_buffer, 0, sizeof(KeyBuffer));    free(key_buffer);}void key_buffer_clear(KeyBuffer *key_buffer){    mmi_mutex_lock(&key_buffer->lock);    key_buffer->head = key_buffer->tail = 0;    mmi_mutex_unlock(&key_buffer->lock);}D_BOOL key_buffer_is_empty(KeyBuffer *key_buffer){    D_BOOL is_empty;    mmi_mutex_lock(&key_buffer->lock);    is_empty = key_buffer_is_empty_unlock(key_buffer);    mmi_mutex_unlock(&key_buffer->lock);    return is_empty;}D_BOOL key_buffer_is_empty_unlock(KeyBuffer *key_buffer){    return key_buffer->head == key_buffer->tail;}void key_buffer_put(KeyBuffer *key_buffer, char ch){    mmi_mutex_lock(&key_buffer->lock);    key_buffer->buf[key_buffer->head] = ch;    key_buffer_cycle_add(key_buffer->head);    if (key_buffer->head == key_buffer->tail)    {        key_buffer_cycle_add(key_buffer->tail);    }    if (key_buffer->waiter > 0)    {        mmi_thread_cond_signal(&key_buffer->cond);    }#ifdef KEY_BUFFER_TEST    int head = (key_buffer->head >= key_buffer->tail)                ? key_buffer->head               : key_buffer->head + KEY_BUFFER_LEN;    int tail = key_buffer->tail;    TRACE("there is number %d char in the key buffer\n", head - tail);#endif    mmi_mutex_unlock(&key_buffer->lock);}D_INT16 key_buffer_get(KeyBuffer *key_buffer, D_INT8 timeout){    D_INT32 ret_waite = 0;    D_INT16 ret_ch;    mmi_mutex_lock(&key_buffer->lock);    if (timeout > 0)    {        struct timespec waite_time = {0};        struct timeval current_time;        gettimeofday(&current_time, NULL);        /* FIXME: 這里的時(shí)間處理看具體的硬件封裝接口 */        //clock_gettime(CLOCK_REALTIME, &waite_time);        waite_time.tv_sec = current_time.tv_sec;        waite_time.tv_sec += timeout;        while (key_buffer_is_empty_unlock(key_buffer) && 0 == ret_waite)        {            key_buffer->waiter++;             TRACE("there is %d waiting for key_buffer\n",key_buffer->waiter);             ret_waite = mmi_thread_cond_timedwait(&key_buffer->cond,                                                   &key_buffer->lock,                                                   &waite_time);            key_buffer->waiter--;             TRACE("there is %d waiting for key_buffer\n",key_buffer->waiter);         }    }    else    {        while (key_buffer_is_empty_unlock(key_buffer) && 0 == ret_waite)        {            key_buffer->waiter++;             TRACE("there is %d waiting for key_buffer\n",key_buffer->waiter);             ret_waite = mmi_thread_cond_wait(&key_buffer->cond, &key_buffer->lock);            key_buffer->waiter--;             TRACE("there is %d waiting for key_buffer\n",key_buffer->waiter);         }    }    if (0 == ret_waite) /* 正常返回 */    {        ret_ch = key_buffer->buf[key_buffer->tail];        key_buffer_cycle_add(key_buffer->tail);        mmi_mutex_unlock(&key_buffer->lock);        return ret_ch;    }    else    {        mmi_mutex_unlock(&key_buffer->lock);        if (timeout)        {            return GET_OVER_TIME;         }        printf("key_buffer_get error !!!\n");        assert(0); /* 在調(diào)試時(shí)，出錯(cuò)停止 */        return GET_OVER_TIME;    }}