#include <fcntl.h> // O_RDONLY
#include <unistd.h>
#include <sys/stat.h> // open, stat and statbuf (get_filesize function)
#include "common.h"
/*  the read function's third argument is only important for the blocksize coming to&from disk */
/*  NOTHING TO DO with size to read; see r_read.c  */
#define BUFFSIZE 12

int 
get_filesize(char *path)
{
struct stat statbuf;

if (stat(path, &statbuf) == -1)
return (-1);
else
return (int) statbuf.st_size;
}


int main(void) {
	int filesize = 0;
	int counter = 0;
	size_t size_to_read = 0; // NOT necessarily int but POSIX says must be unsigned int
	char * filename = "readblock.c";
	char * buf;
	ssize_t bread = 0;
	filesize = get_filesize(filename);
	if (filesize == -1) {
		printf("problem getting filesize, returned -1 meaning ERROR\n\n");
		return -1;
	}
	if (BUFFSIZE < (int)filesize)  {
		size_to_read = BUFFSIZE;
		if ((buf = (char *)malloc(size_to_read+1)) == NULL) {
			printf("malloc error for %d bytes\n\n", size_to_read);
		}
	} else  {
		size_to_read = filesize;
		if ((buf = (char *)malloc(size_to_read+1)) == NULL) {
			printf("malloc error for %d bytes\n\n", size_to_read);
		}
	}
	memset(buf, 'h', size_to_read+1);
	buf[size_to_read]='\0';
	printf("original: %s\n", buf);
	printf("before reading %d: (values are one less because of array notation)\n", (int)size_to_read);
	printf("at position %d the value  %c \n", size_to_read-2, buf[size_to_read-2]);  
	printf("at position %d the value  %c \n", size_to_read-1, buf[size_to_read-1]);  // print last character read
	printf("at position %d the value  %c \n", size_to_read, buf[size_to_read]);  
	int fd = open(filename, O_RDONLY);
	if (fd < 0) {
		printf("error in %s for reading\n", filename);
		return -1;
		}
	bread = read(fd, buf, size_to_read);   
	/*  bread = read(fd, buf, filesize);   GULPS gulps entire file; why doesn't stop at filesize?? that's why segfault */
	if (bread == -1) {
		printf("read error\n\n");
		return -1;
	}
	printf("the %d first bytes of %s in hexadecimal ", size_to_read, filename);
	// while (buf) {  // keeps going and going ... SEGFAULTINg: question answered: does not append SHIT onto buf
//		printf(" %x ", *buf);
//		buf++;
//	}
	 while (counter < size_to_read) {  
		counter++;
	}
	// okay since counter starts at 0 and bread is always > 0
	printf("later: %s\n", buf);
	printf("after reading %d: (values are one less because of array notation)\n", (int)size_to_read);
	printf("at position %d the value  %c \n", counter-1, buf[counter-1]);  
	printf("at position %d the value  %c \n", counter, buf[counter]);  // print last character read
	printf("at position %d the value  %c \n", counter+1, buf[counter+1]);  
	return 0;
}