ringbuffer剖析

#include <stdio.h>

#define WAVEOUT_BUF_GUARD	  1
#define MAX_QUEUE             1
#define WAVEOUT_BUF_BLK_NUM   16
#define WAVEOUT_BUF_BLK_SIZE  1024

int audio_dma_has_worked = 0;
typedef struct {
int read;
int write;
int lastsize;
unsigned char *buf;
}_wave_buf;

_wave_buf WaveBuffer;

void Audio_MAL_Play(unsigned int Addr, unsigned int Size)
{

int read     = WaveBuffer.read;
int write     = WaveBuffer.write;
int lastsize = WaveBuffer.lastsize;
int queued;

if(write >= read)
queued = write - read;
else
queued = WAVEOUT_BUF_BLK_NUM - (read - write);

if(queued >0)
{

/*after send data ,we need to update buffer*/
if(WaveBuffer.read != WaveBuffer.write)
{
WaveBuffer.read ++;
if(WaveBuffer.read >= WAVEOUT_BUF_BLK_NUM)
{
WaveBuffer.read = 0;
}
}
}
}

void WaveOut_Init(void)
{
WaveBuffer.read = 0;
WaveBuffer.write = 0;
WaveBuffer.lastsize = 0;
WaveBuffer.buf = (unsigned char *)malloc(WAVEOUT_BUF_BLK_SIZE*WAVEOUT_BUF_BLK_NUM);
if( 0 != WaveBuffer.buf )
{
printf(" WaveOut_Init malloc successl\n");
memset(WaveBuffer.buf, 0, WAVEOUT_BUF_BLK_SIZE*WAVEOUT_BUF_BLK_NUM);
}
else
{
printf(" WaveOut_Init malloc fail\r\n");
WaveBuffer.buf = NULL;
}
}

void A2dp_WaveOut_Close()
{
printf("A2dp_WaveOut_Close\r\n");

WaveBuffer.read = 0;
WaveBuffer.write = 0;
WaveBuffer.lastsize = 0;
if(0 != WaveBuffer.buf)
{
printf("free wave buffer\n");
free(WaveBuffer.buf);
WaveBuffer.buf = NULL;
}

}

void A2dp_WaveOut_GetBuffer(unsigned char **outBufPtr, int *outBufSize)
{

int read     = WaveBuffer.read;
int write     = WaveBuffer.write;
int lastsize = WaveBuffer.lastsize;
int queued;

if((write + 1) % WAVEOUT_BUF_BLK_NUM == read)
{
printf("WARNING : ring buffer is FUll\n");

*outBufPtr  = 0;
*outBufSize = 0;
}

printf("A2dp_WaveOut_GetBuffer read is %d,write is %d,lastsize is %d\n",read,write,lastsize);
if(write >= read)
{
queued = write - read;
}
else
queued = WAVEOUT_BUF_BLK_NUM - (read - write);

*outBufPtr  = WaveBuffer.buf + write*WAVEOUT_BUF_BLK_SIZE + lastsize;
*outBufSize = WAVEOUT_BUF_BLK_SIZE;

}

void A2dp_WaveOut_Write(int waveOutSize)
{
int queued;
int read     = WaveBuffer.read;
int write     = WaveBuffer.write;
int lastsize = WaveBuffer.lastsize;

printf("A2dp_WaveOut_Write read is %d,write is %d,lastsize is %d\n",read,write,lastsize);
lastsize += waveOutSize;
printf("A2dp_WaveOut_Write read is %d,write is %d,lastsize is %d\n",read,write,lastsize);

if(lastsize >= WAVEOUT_BUF_BLK_SIZE)
{
lastsize -= WAVEOUT_BUF_BLK_SIZE;
write++;
if(write >= WAVEOUT_BUF_BLK_NUM)
{

//return to the frist buffer
if(lastsize)
{
memcpy(WaveBuffer.buf,  WaveBuffer.buf + (WAVEOUT_BUF_BLK_NUM)*WAVEOUT_BUF_BLK_SIZE,  lastsize);
}
write = 0;
}
}

WaveBuffer.write     = write;
WaveBuffer.lastsize = lastsize;

if(write >= read)
queued = write - read;
else
queued = WAVEOUT_BUF_BLK_NUM - (read - write);

if(queued >= 1)
Audio_MAL_Play((unsigned int)(WaveBuffer.buf + WaveBuffer.read*WAVEOUT_BUF_BLK_SIZE), WAVEOUT_BUF_BLK_SIZE/*/2*/  );

}

int main()
{
unsigned char *waveOutBufPtr;
int waveOutBufSize;
unsigned char music_data1[222] = {0};
unsigned char music_data2[888] = {0};
unsigned char music_data3[1024] = {0};
unsigned char music_data4[1222] = {0};
unsigned char music_data5[2500] = {0};
memset(&music_data1,1,sizeof(music_data1));
memset(&music_data2,2,sizeof(music_data2));
memset(&music_data3,3,sizeof(music_data3));
memset(&music_data4,4,sizeof(music_data4));
memset(&music_data5,5,sizeof(music_data5));

WaveOut_Init();

//模拟五次来MUSIC STREAM
A2dp_WaveOut_GetBuffer(&waveOutBufPtr, &waveOutBufSize);
if(waveOutBufPtr != NULL)
{
memcpy(waveOutBufPtr,music_data1,sizeof(music_data1));
A2dp_WaveOut_Write(sizeof(music_data1));
}

A2dp_WaveOut_GetBuffer(&waveOutBufPtr, &waveOutBufSize);
if(waveOutBufPtr != NULL)
{
memcpy(waveOutBufPtr,music_data2,sizeof(music_data2));
A2dp_WaveOut_Write(sizeof(music_data2));
}

A2dp_WaveOut_GetBuffer(&waveOutBufPtr, &waveOutBufSize);
if(waveOutBufPtr != NULL)
{
memcpy(waveOutBufPtr,music_data3,sizeof(music_data3));
A2dp_WaveOut_Write(sizeof(music_data3));
}

A2dp_WaveOut_GetBuffer(&waveOutBufPtr, &waveOutBufSize);
if(waveOutBufPtr != NULL)
{
memcpy(waveOutBufPtr,music_data4,sizeof(music_data4));
A2dp_WaveOut_Write(sizeof(music_data4));
}

A2dp_WaveOut_GetBuffer(&waveOutBufPtr, &waveOutBufSize);
if(waveOutBufPtr != NULL)
{
memcpy(waveOutBufPtr,music_data5,sizeof(music_data5));
A2dp_WaveOut_Write(sizeof(music_data5));
}

A2dp_WaveOut_Close();
return 0;
}