103 lines
2.1 KiB
C
Executable File
103 lines
2.1 KiB
C
Executable File
#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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typedef struct Node
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{
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int32_t key;
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int32_t left_idx;
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int32_t right_idx;
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} Node;
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int
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convert_num_to_sys(char num[])
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{
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unsigned res = 0;
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for (int i = 0; i < sizeof(res); ++i) {
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unsigned cur = (unsigned char) num[sizeof(res) - i - 1];
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res ^= (cur << (CHAR_BIT * i));
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}
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return (int) res;
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}
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int
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read_int(int fd)
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{
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int res = 0;
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char buf[sizeof(res)];
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int pos = 0;
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while (pos != sizeof(res)) {
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ssize_t off = read(fd, buf + pos, sizeof(res) - pos);
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if (off == -1) {
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printf("Error, can't read from file\n");
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exit(1);
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}
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pos += off;
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}
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res = convert_num_to_sys(buf);
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return res;
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}
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Node
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read_node(int fd)
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{
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Node new_node;
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new_node.key = read_int(fd);
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new_node.right_idx = read_int(fd);
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new_node.left_idx = read_int(fd);
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return new_node;
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}
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void
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dfs(Node head, int fd)
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{
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if (head.left_idx != 0) {
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if (lseek(fd, head.left_idx * sizeof(Node), SEEK_SET) == -1) {
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printf("Error? can't seek throw file\n");
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exit(1);
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}
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Node left_node = read_node(fd);
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dfs(left_node, fd);
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}
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printf("%d\n", head.key);
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if (head.right_idx != 0) {
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if (lseek(fd, head.right_idx * sizeof(Node), SEEK_SET) == -1) {
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printf("Error? can't seek throw file\n");
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exit(1);
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}
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Node right_node = read_node(fd);
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dfs(right_node, fd);
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}
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}
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int
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main(int argc, char *argv[])
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{
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if (argc < 2) {
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printf("Error: Not enough argumens\n");
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exit(1);
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}
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int fd = open(argv[1], O_RDONLY, 0600);
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if (fd < 0) {
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printf("Error: Can't open file\n");
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exit(1);
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}
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struct stat st;
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if (stat(argv[1], &st) == -1) {
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printf("Error, can't get info about file\n");
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exit(1);
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}
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if (st.st_size == 0) {
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return 0;
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}
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Node head = read_node(fd);
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dfs(head, fd);
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close(fd);
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}
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