/* gcc -W -Wall -o pageslack pageslack.c */

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

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>

#define PAGE_SIZE (1UL << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE - 1))

unsigned long long total;
unsigned long long slack[5];

void do_dir(const char *name)
{
	DIR *dir; 
	struct dirent *ent;

	dir = opendir(name);
	if (!dir) {
		perror("opendir");
		exit(EXIT_FAILURE);
	}
	while ((ent = readdir(dir))) {
		struct stat buf;
		char path[PATH_MAX];

		if (!strcmp(ent->d_name, "."))
			continue;
		if (!strcmp(ent->d_name, ".."))
			continue;

		sprintf(path, "%s/%s", name, ent->d_name);
		if (stat(path, &buf)) {
			perror("stat");
			exit(EXIT_FAILURE);
		}
		if (S_ISDIR(buf.st_mode)) {
			do_dir(path);
			continue;
		}
		if (S_ISREG(buf.st_mode)) {
			int i;

			for (i = 0; i < 5; i++) {
				unsigned long PAGE_SHIFT = 12 + i;
				slack[i] += (PAGE_SIZE - (buf.st_size % PAGE_SIZE)) % PAGE_SIZE;
			}
			total += buf.st_size;
		}
	}
	if (closedir(dir)) {
		perror("closedir");
		exit(EXIT_FAILURE);
	}
}

int main(void)
{
	do_dir(".");
	printf("total\t: %llu\n", total);
	printf(" 4k\t: %llu (%llu%%)\n", slack[0], (100 * slack[0]) / total);
	printf(" 8k\t: %llu (%llu%%)\n", slack[1], (100 * slack[1]) / total);
	printf("16k\t: %llu (%llu%%)\n", slack[2], (100 * slack[2]) / total);
	printf("32k\t: %llu (%llu%%)\n", slack[3], (100 * slack[3]) / total);
	printf("64k\t: %llu (%llu%%)\n", slack[4], (100 * slack[4]) / total);
	return EXIT_SUCCESS;
}