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200-cell CircBuffer works

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This commit is contained in:
Sergiusz Warga 2021-05-02 00:02:49 +02:00
parent 827533b42a
commit 8744096312
4 changed files with 177 additions and 100 deletions
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10
Task-8/CircBuffer.h Normal file
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struct CircBuffer {
union {
struct {
int size;
int free_idx;
} info;
char padding[1024];
};
double data[200];
};

80
Task-8/k_avg.c Normal file
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//
// Written for Computer Networks and Systems lab classes
// AUTHOR : Sergiusz Warga
#include <fcntl.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
#include <time.h>
#include "CircBuffer.h"
#define PI 3.14
#define SIG_FREQ 100
#define SAM_FREQ 2000
_Noreturn void k_avg(int fd) {
// Exponential Moving Average should be updated with f = 10Hz (i.e. every 200 samples).
int samples = 200;
printf("A k_avg has been called\n");
struct CircBuffer *buffer;
buffer = mmap(NULL, sizeof(struct CircBuffer*), PROT_READ, MAP_SHARED, fd, 0);
if (buffer == MAP_FAILED) {
fprintf(stderr, "mmap: ");
exit(EXIT_FAILURE);
}
struct timespec delay;
delay.tv_sec = 0;
delay.tv_nsec = 100000000ULL*1; // 100ms == 100 000 000ns -> 10Hz
double alpha = 0.1;
double ema;
int start_idx = 0;
while (1) {
start_idx = buffer->info.free_idx;
ema = buffer->data[start_idx];
printf("start_idx = %d\n", start_idx);
printf("EMA = %lf\n", ema);
nanosleep(&delay, NULL);
}
// while (1) {
// start_idx = (buffer->info.free_idx - samples) % buffer->info.size;
// printf("start_idx = %d\n", start_idx);
// ema = buffer->data[start_idx];
// for (int read_idx = start_idx + 1; read_idx < samples; read_idx = ++read_idx % buffer->info.size) {
// ema = alpha*buffer->data[read_idx] + (1 - alpha) * ema;
// printf("EMA[%d] = %lf\n", read_idx, ema);
// }
// printf("EMA = %lf\n", ema);
// nanosleep(&delay, NULL);
// }
}
int main(int argc, char *argv[]) {
//----- Open a shared memory -----
const char *memory_name = "/dsp";
int fd = shm_open(memory_name, O_RDONLY, 0777);
if (fd < 0) {
fprintf(stderr, "shm_open: ");
exit(EXIT_FAILURE);
}
printf("Shared memory file descriptor: %d\n", fd);
k_avg(fd);
return 0;
}

87
Task-8/producer.c Normal file
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//
// Written for Computer Networks and Systems lab classes
// AUTHOR : Sergiusz Warga
#include <fcntl.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
#include <time.h>
#include "CircBuffer.h"
#define PI 3.14
#define SIG_FREQ 100
#define SAM_FREQ 2000
double get_sample(int signal_frequeuncy, int sampling_frequency, int sample_no) {
// TODO: Just a sketch, gotta rewrite
double step = 2.*PI/200;
return sin(sample_no*step);
}
_Noreturn void producer(int fd) { // That's something new I've learned and I think that
// function specifiers are cute.
printf("The producer has been called\n");
struct CircBuffer *buffer;
buffer = mmap(NULL, sizeof(struct CircBuffer), PROT_WRITE, MAP_SHARED, fd, 0);
if (buffer == MAP_FAILED) {
fprintf(stderr, "mmap: ");
exit(EXIT_FAILURE);
}
int i = 0;
int free_idx = 0;
struct timespec delay;
delay.tv_sec = 0;
delay.tv_nsec = 500000ULL*1; // 0.5ms == 500 000ns -> 2kHz
while (1) {
free_idx = buffer->info.free_idx; // For more readable code
buffer->data[free_idx] = get_sample(SIG_FREQ, SAM_FREQ, i+1); // Put a sample into the buffer
buffer->info.free_idx = (free_idx + 1 ) % buffer->info.size; // Increase the free-cell index
printf("CircBuffer[%d] = \t %lf\n", free_idx, buffer->data[free_idx]);
i = ++i % 200;
nanosleep(&delay, NULL);
}
}
int main(int argc, char *argv[]) {
//----- Create a shared memory -----
const char *memory_name = "/dsp";
int fd = shm_open(memory_name, O_CREAT | O_RDWR, 0777);
if (fd < 0) {
fprintf(stderr, "shm_open: ");
exit(EXIT_FAILURE);
}
printf("Shared memory file descriptor: %d\n", fd);
//----- Truncate memory to the buffer's size
if (ftruncate(fd, sizeof(struct CircBuffer)) < 0) {
fprintf(stderr, "ftruncate: \n");
exit(EXIT_FAILURE);
}
//----- Initialize the buffer -----
struct CircBuffer *buffer;
buffer = (struct CircBuffer *)mmap(NULL, sizeof(struct CircBuffer), PROT_WRITE, MAP_SHARED, fd, 0);
if (buffer == MAP_FAILED) {
fprintf(stderr, "mmap: ");
exit(EXIT_FAILURE);
}
buffer->info.size = sizeof(buffer->data)/sizeof(double);
buffer->info.free_idx = 0;
producer(fd);
return 0;
}

100
Task-8/task_8_2.c
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// Producer:
// Retransfers sinusoidal signal sampled at a frequency of 2kHz
// Writes to the circular buffer:
// Write sample into the free buffer position
// Incremets the free position by one
// After idx = size go to the beginning
// Consumers:
//
#include <fcntl.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
#include <time.h>
#define PI 3.14
// void generate_signal(double *signal, int n_samples) {
// static double signal[n_samples];
// double step = 2.*PI/(double)n_samples;
// for (int i = 0; i < n_samples; ++i) {
// signal[i] = sin(i*step);
// }
// }
struct CircBuffer {
union {
struct {
int size;
int rd_idx;
int wr_idx;
} info;
char padding[1024];
};
int data[1024];
};
void producer(const char * memory_name, int fd) {
printf("The producer has been called\n");
double signal[] = {0, 0.7, 1, 0.7, 0};
struct CircBuffer *buffer;
buffer = mmap(NULL, 64, PROT_WRITE, MAP_SHARED, fd, 0);
if (buffer == MAP_FAILED) {
fprintf(stderr, "mmap: ");
exit(EXIT_FAILURE);
}
}
int main(int argc, char *argv[]) {
int buffer_size = 64;
const char *memory_name = "/dsp";
int fd = shm_open(memory_name, O_CREAT | O_RDWR, 0777);
if (fd < 0) {
fprintf(stderr, "shm_open: ");
exit(EXIT_FAILURE);
}
printf("Shred memory file descriptor: %d\n", fd);
// double *signal;
// generate_signal(signal, 100);
struct CircBuffer *buffer;
if (ftruncate(fd, sizeof(struct CircBuffer)) < 0) {
fprintf(stderr, "ftruncate: \n");
exit(EXIT_FAILURE);
}
pid_t pid;
pid = fork();
if (pid == -1) {
perror("fork: ");
exit(EXIT_FAILURE);
}
if (pid == 0) {
buffer = (struct CircBuffer *)mmap(NULL, sizeof(buffer), PROT_READ, MAP_SHARED, fd, 0);
if (buffer == MAP_FAILED) {
fprintf(stderr, "mmap: ");
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
} else {
producer(memory_name, fd);
}
return 0;
}