sys_prog/midterm/processes/processes.c

#include <stdio.h>
#include <stdlib.h>
#include "processes.h"

typedef unsigned int uint;
typedef unsigned long int ulong;

const ulong INIT_CAP = 1024;

struct process {
	uint pid;
	uint ppid;
	char user[9];
	float priority;
	ulong resident_size;
	ulong size;
	ulong virtual_size;
	char command[16];
};

struct processes {
	ulong size;
	ulong capacity;
	struct process* procs;
};

struct processes* new_processes() {
	struct processes* p = malloc(sizeof(struct processes));
	if (!p) {
		return NULL;
	}

	struct process* p_arr = malloc(INIT_CAP * sizeof(struct process));
	if (!p_arr) {
		free(p);
		return NULL;
	}

	p->size = 0;
	p->capacity = INIT_CAP;
	p->procs = p_arr;
	return p;
}

void delete(struct processes* p) {
	free(p->procs);
	free(p);
}

int add_from_file(struct processes* ps, const char* filename) {
	FILE* f = fopen(filename, "r");
	if (!f) {
		return 0;
	}

	struct process p;
	while (fscanf(f, "%u %u %8s %f %lu %lu %lu %15s\n", &p.pid, &p.ppid,
			p.user, &p.priority,&p.resident_size, &p.size,
			&p.virtual_size, p.command) == 8) {

		if (ps->size == ps->capacity) {
			ps->capacity *= 2;
			struct process* new_procs = realloc(ps->procs,
				ps->capacity * sizeof(struct process));
			if (!new_procs) {
				return 0;
			}
			ps->procs = new_procs;
		}

		ps->procs[ps->size] = p;
		ps->size++;
	}
}