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

int recur_count = 0;
int find_word(char* word, char* search_area, int area_length){
	recur_count++;
	if(area_length < 2) {
		printf("We gave up\n");
		return 0;
	}
	int middle = area_length / 2;
	while(search_area[middle] != '\n' && middle >= 0)
		middle--;
	middle++;
	int end_of_middle_word = middle;
	while(search_area[end_of_middle_word] != '\n')
		end_of_middle_word++;
	write(1, search_area + middle, end_of_middle_word - middle);

	int res = strncmp(word, search_area + middle, end_of_middle_word - middle);
	if(!res){
		printf("   We found the word!\n");
		return middle;
	} else if(res < 0){
		printf("   Look earlier\n");
		return find_word(word, search_area, middle);
	} else {
		printf("   Look later\n");
		return find_word(word, search_area + end_of_middle_word, area_length - end_of_middle_word);
	}
}

int main(int argc, char ** argv){
	if(argc < 2){
		printf("Usage:  %s word\n", argv[0]);
		return 1;
	}
	int fd = open("/usr/share/dict/american-english", O_RDONLY);
	/* This wasn't in the in-class demo.  We just used 1024*1024 */
	struct stat stats;
	fstat(fd, &stats);	
	printf("File size is %d bytes\n", stats.st_size);
	/* After this is just like in class, with two exceptions:
 	 * 	1.  I changed 1024*1024 to stats.st_size everywhere it occured
 	 * 	2.  I changed the output format to be more concise
 	 */
	char *file_data = mmap(0, stats.st_size, PROT_READ, MAP_SHARED, fd, 0);

	find_word(argv[1], file_data, stats.st_size);
	printf("Took %d calls\n", recur_count);

	munmap(file_data, stats.st_size);
	close(fd);
	return 0;
}