udp-recv.c

/*
        demo-udp-03: udp-recv: a simple udp server
	receive udp messages

        usage:  udp-recv

        Paul Krzyzanowski
*/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include "port.h"
#include <portaudio.h>

#define BUFSIZE 2048


/* #define SAMPLE_RATE  (17932) // Test failure to open with this value. */
#define SAMPLE_RATE  (44100)
#define FRAMES_PER_BUFFER (512)
#define NUM_SECONDS     (5)
#define NUM_CHANNELS    (2)
/* #define DITHER_FLAG     (paDitherOff) */
#define DITHER_FLAG     (0) /**/
/** Set to 1 if you want to capture the recording to a file. */
#define WRITE_TO_FILE   (0)

/* Select sample format. */
#if 1
#define PA_SAMPLE_TYPE  paFloat32
typedef float SAMPLE;
#define SAMPLE_SILENCE  (0.0f)
#define PRINTF_S_FORMAT "%.8f"
#elif 1
#define PA_SAMPLE_TYPE  paInt16
typedef short SAMPLE;
#define SAMPLE_SILENCE  (0)
#define PRINTF_S_FORMAT "%d"
#elif 0
#define PA_SAMPLE_TYPE  paInt8
typedef char SAMPLE;
#define SAMPLE_SILENCE  (0)
#define PRINTF_S_FORMAT "%d"
#else
#define PA_SAMPLE_TYPE  paUInt8
typedef unsigned char SAMPLE;
#define SAMPLE_SILENCE  (128)
#define PRINTF_S_FORMAT "%d"
#endif

typedef struct
{
    int          frameIndex;  /* Index into sample array. */
    int          maxFrameIndex;
    SAMPLE      *recordedSamples;
}
paTestData;



static int playCallback( const void *inputBuffer, void *outputBuffer,
                         unsigned long framesPerBuffer,
                         const PaStreamCallbackTimeInfo* timeInfo,
                         PaStreamCallbackFlags statusFlags,
                         void *userData )
{
    paTestData *data = (paTestData*)userData;
    SAMPLE *rptr = &data->recordedSamples[data->frameIndex * NUM_CHANNELS];
    SAMPLE *wptr = (SAMPLE*)outputBuffer;
    unsigned int i;
    int finished;
    unsigned int framesLeft = data->maxFrameIndex - data->frameIndex;

    (void) inputBuffer; /* Prevent unused variable warnings. */
    (void) timeInfo;
    (void) statusFlags;
    (void) userData;

    if( framesLeft < framesPerBuffer )
    {
        /* final buffer... */
        for( i=0; i<framesLeft; i++ )
        {
            *wptr++ = *rptr++;  /* left */
            if( NUM_CHANNELS == 2 ) *wptr++ = *rptr++;  /* right */
        }
        for( ; i<framesPerBuffer; i++ )
        {
            *wptr++ = 0;  /* left */
            if( NUM_CHANNELS == 2 ) *wptr++ = 0;  /* right */
        }
        data->frameIndex += framesLeft;
        finished = paComplete;
    }
    else
    {
        for( i=0; i<framesPerBuffer; i++ )
        {
            *wptr++ = *rptr++;  /* left */
            if( NUM_CHANNELS == 2 ) *wptr++ = *rptr++;  /* right */
        }
        data->frameIndex += framesPerBuffer;
        finished = paContinue;
    }
    return finished;
}

int
main(int argc, char **argv)
{
	struct sockaddr_in myaddr;	/* our address */
	struct sockaddr_in remaddr;	/* remote address */
	socklen_t addrlen = sizeof(remaddr);		/* length of addresses */
	int recvlen;			/* # bytes received */
	int fd;				/* our socket */
	int msgcnt = 0;			/* count # of messages we received */
	unsigned char buf[BUFSIZE];	/* receive buffer */


	/* create a UDP socket */

	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
		perror("cannot create socket\n");
		return 0;
	}

	/* bind the socket to any valid IP address and a specific port */

	memset((char *)&myaddr, 0, sizeof(myaddr));
	myaddr.sin_family = AF_INET;
	myaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	myaddr.sin_port = htons(SERVICE_PORT);

	if (bind(fd, (struct sockaddr *)&myaddr, sizeof(myaddr)) < 0) {
		perror("bind failed");
		return 0;
	}

	/* now loop, receiving data and printing what we received */
	for (;;) {
		printf("waiting on port %d\n", SERVICE_PORT);
		recvlen = recvfrom(fd, buf, BUFSIZE, 0, (struct sockaddr *)&remaddr, &addrlen);
		if (recvlen > 0) {
			buf[recvlen] = 0;
			
			/* CALLBACK */
			//printf("received message: \"%s\" (%d bytes)\n", buf, recvlen);
		}
		else
			printf("uh oh - something went wrong!\n");
		sprintf(buf, "ack %d", msgcnt++);
		printf("sending response \"%s\"\n", buf);
		if (sendto(fd, buf, strlen(buf), 0, (struct sockaddr *)&remaddr, addrlen) < 0)
			perror("sendto");
	}
	/* never exits */
}