Simple mail server (SMTP & POP3 implementations).

esmail.c

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>


/*
 * Slots
 */
typedef struct {
	uint32_t  count;
	uint32_t  size;
	uint32_t *array;
} Slots;

static void      slots_init(Slots *self, uint32_t *ptr, size_t size);
static uint32_t *slots_init_alloc(Slots *self, size_t size);
static int       slots_push(Slots *self, uint32_t udata);
static int64_t   slots_pop(Slots *self);


/*
 * SMTP
 */
typedef struct {
} SmtpClient;

typedef struct {
} Smtp;


/*
 * POP3
 */
typedef struct {
} Pop3Client;

typedef struct {
} Pop3;


/*
 * Impl
 */


/*
 * Slots
 */
static void
slots_init(Slots *self, uint32_t *ptr, size_t size)
{
	self->count = 0;
	self->array = ptr;
	self->size = size;
}


static uint32_t *
slots_init_alloc(Slots *self, size_t size)
{
	void *const array = malloc(sizeof(uint32_t) * size);
	if (array == NULL)
		return NULL;

	slots_init(self, array, size);
	return array;
}


static int
slots_push(Slots *self, uint32_t udata)
{
	const uint32_t count = self->count;
	if (count == self->size)
		return -1;

	self->array[count] = udata;
	self->count = count +1;
	return 0;
}


static int64_t
slots_pop(Slots *self)
{
	uint32_t count = self->count;
	if (count == 0)
		return -1;

	count--;
	self->count = count;
	return (int64_t)self->array[count];
}


/*
 * main
 */
int
main(int argc, char *argv[])
{
	return 0;
}