#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>

static void write_test(char *buf, int size)
{
	int i;

	printf("Try to write %p for %x size.\n", buf, size);
	for (i = 0; i < size; i++)
		buf[i] = (char)(i & 0xFF);
	printf("Write Done.\n");
}

static void read_test(char *buf, int size)
{
	int i;

	printf("Try to read %p for %x size.\n", buf, size);
	for (i = 0; i < size; i++)
		if (buf[i] != (char)(i & 0xFF)) {
			printf("Read Check failed.\n");
			printf("Index %x, %c expect %x.\n", i, buf[i], i & 0xFF);
			exit(-1);
		}
	printf("Read Done.\n");
}

static void fread_test(int fd, int size)
{
	char buf;
	int i;

	i = lseek(fd, 0, SEEK_END);
	printf("End: %x.\n", i);

	i = lseek(fd, 0, SEEK_SET);
	if (i != 0) {
		perror("seek");
		exit(-1);
	}

	printf("Try to fread fd=%d size %x sizeof(buf) %ld.\n", fd, size,
		sizeof(buf));

	for (i = 0; i < size; i++) {
		int ret;

		ret = read(fd, &buf, sizeof(buf));
		if (ret != sizeof(buf)) {
			printf("Read failed, offset %x, ret %d ftell %ld.\n",
				i, ret, lseek(fd, 0, SEEK_CUR));
			perror("read");
			exit(-1);
		}
		if (buf != (char)(i & 0xFF)) {
			printf("Read Check failed.\n");
			printf("Index %x, %c expect %x.\n", i, buf, i & 0xFF);
			exit (-1);
		}
	}

	printf("Fread Done.\n");
}

int main(int argc, char *argv[])
{
	char *filename;
	char *buf;
	int fd;

	if (argc < 2) {
		printf("arg: filename.\n");
		return -1;
	}

	filename = argv[1];
	printf("mmap test on %s.\n", filename);

	fd = open(filename, O_RDWR);
	if (fd < 0) {
		perror("open");
		return -1;
	}

	if (lseek(fd, 0x1000, SEEK_SET) != 0x1000) {
		perror("seek");
		return -1;
	}

	if (ftruncate(fd, 0x1000) != 0) {
		perror("ftruncate");
		return -1;
	}

//	return 0;

	buf = mmap(NULL, 0x1000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	if (buf == MAP_FAILED) {
		perror("mmap");
		return -1;
	}

	write_test(buf, 0x1000);
	read_test(buf, 0x1000);
	msync(buf, 0x1000, MS_SYNC);
	fread_test(fd, 0x1000);

	close(fd);

	return 0;
}