memory-play.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MEM_SIZE_KBYTES 32
#define MEM_SIZE (1024 * MEM_SIZE_KBYTES)

struct vehicle {
	char serial[32];
	char name[32];
	double km;
} vehicle;

struct config {
	char serial[32];
	char name[32];
} cfg;

struct gpslog {
	struct {
		double lat;
		double lon;
	} entry[64];
} gpslog;

char memory[MEM_SIZE];


void write8(int address, char byte) {
	memory[address] = byte;
}

char read8(int address) {
	return memory[address];
}

int openmem(char *file) {
	FILE *fp;

	fp = fopen(file, "r");

	if (fp == NULL)
		return 1;

	size_t r;
	r = fread(memory, sizeof(char), MEM_SIZE, fp);
	fclose(fp);
	printf("read %zu bytes from memory\n", r);
	return 0;
}

int dumpmem(char *file) {
	FILE *fp;

	fp = fopen(file, "w");

	if (fp == NULL)
		return 1;

	size_t r = fwrite(memory, sizeof(char), MEM_SIZE, fp);
	fclose(fp);
	printf("%zu bytes written to memry\n", r);
	return 0;
}
void initmem() {
	int i;

	printf("zeroing memory...\n");
	for (i = 0; i < MEM_SIZE; i++) {
		fprintf(stdout, "0x%04X ", i);
		fflush(stdout);
		memory[i] = '\0';

	}
	printf("\n");
}
void writemem(int addr, void *mem, size_t size) {
	printf("writing %zu bytes to memory at address %04X - %04X\n", size, addr, addr + (int) size);
	int i = 0;
	unsigned char *byte;
	for (byte = (unsigned char *)mem; size--; ++byte) {
		memory[addr + (i++)] = *byte;
	}
}

void readmem(int addr, void *mem, size_t size) {
	char buf[size];
	int n;
	for (n = 0; n < size; n++) {
		buf[n] = memory[addr + n];
	}
	memcpy(mem, buf, size);
}
void setup() {
	int r;
openmem:
	r = openmem("memory.txt");

	if (r) {
		initmem();
		strcpy(vehicle.serial, "E312312-D43M");
		strcpy(vehicle.name, "xyz");
		vehicle.km = 23.43;
		writemem(0, &vehicle, sizeof(cfg));
		gpslog.entry[0].lat = 55.3235;
		gpslog.entry[0].lon = 11.2453;
		gpslog.entry[1].lat = 22.2222;
		gpslog.entry[1].lon = 33.3333;
		writemem(8000, &gpslog, sizeof(gpslog));
		int x = -1022;
		writemem(500, &x, sizeof(x));
		dumpmem("memory.txt");
		goto openmem;
	}

	readmem(0, &vehicle, sizeof(cfg));

	struct gpslog mylog;
	readmem(8000, &mylog, sizeof(mylog));

	int y;
	readmem(500, &y, sizeof(y));

	printf("entry0: lat: %f, lon: %f, y: %d\n", mylog.entry[0].lat, mylog.entry[0].lon, y);
	dumpmem("memory.txt");
}
int main() {
	setup();
	printf("serial: %s\nname: %s\n", vehicle.serial, vehicle.name);
	return 0;
}