ZeroMQ baseband subscriber

zmq-sub.c

/*
to pass IQ baseband samples to SX1255 over I2S, run this:
./zmq-sub | aplay -t raw -f S32_LE -r 192000 -c 2 --device="hw:0,0"

note: you need to enable I2S overlay (acting as a slave)
this one works good: https://github.com/AkiyukiOkayasu/RaspberryPi_I2S_Slave
note: setting the rate to 192k isn't really effective, the actual rate is 125k (governed by the I2S master - SX1255)
*/

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <zmq.h>

#define SAMP_FLOAT

void *zmq_ctx;
void *bsb_uplink;

int rcvd;
uint8_t inp[100000];

int main(void)
{
	zmq_ctx = zmq_ctx_new();
	bsb_uplink = zmq_socket(zmq_ctx, ZMQ_SUB);
	
	printf("ZeroMQ ");
	if(zmq_connect(bsb_uplink, "tcp://10.10.10.17:17018")==0)
		printf("OK\n");
	else
		printf("ERROR\n");
	
	zmq_setsockopt(bsb_uplink, ZMQ_SUBSCRIBE, "", 0);
	
	while(1)
	{
		rcvd=zmq_recv(bsb_uplink, inp, sizeof(inp), 0);
		
		if(rcvd!=-1)
		{
			#if defined(SAMP_INT32)
			write(STDOUT_FILENO, inp, rcvd);
			
			#elif defined(SAMP_FLOAT)
			int32_t val[15000];
			for(int j=0; j<rcvd; j+=8)
			{
				val[(j/8)*2]  =*(float*)&inp[j  ]*0x7FFFFFFFL;
				val[(j/8)*2+1]=*(float*)&inp[j+4]*0x7FFFFFFFL;
			}
			write(STDOUT_FILENO, (uint8_t*)val, rcvd);
			#endif
		}
	}
	
	return 0;
}