init commit

3sem/cnts/contest4/04-copy.c

@@ -0,0 +1,98 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <limits.h>
+#include <stdint.h>
+
+struct Node
+{
+    int32_t key;
+    int32_t left_idx;
+    int32_t right_idx;
+};
+
+void
+read_struct(int fd, struct Node *node, int is_le)
+{
+    unsigned char buf[sizeof(*node)];
+    int n = 0;
+    while (n != sizeof(*node)) {
+        ssize_t off = read(fd, buf + n, sizeof(*node) - n);
+        if (off == -1) {
+            close(fd);
+            exit(1);
+        }
+        n += off;
+    }
+    // int r = read(fd, buf, sizeof(*node));
+    // if (r == -1) {
+    //     close(fd);
+    //     exit(1);
+    // }
+
+    int n_byte = sizeof(int32_t);
+    node->key = 0;
+    node->left_idx = 0;
+    node->right_idx = 0;
+
+    for (int j = 0; j < n_byte; ++j) {
+        int off = (is_le) ? (CHAR_BIT * (sizeof(uint32_t) - (j + 1))) : (CHAR_BIT * j);
+
+        node->key |= (uint32_t) buf[j] << off;
+        node->left_idx |= (uint32_t) buf[j + n_byte * 1] << off;
+        node->right_idx |= (uint32_t) buf[j + n_byte * 2] << off;
+    }
+}
+
+void
+inorder_traversal(int fd, int32_t idx, int is_le)
+{
+    if (idx == 0) {
+        return;
+    }
+    if (idx == -1) {
+        idx = 0;
+    }
+
+    struct Node tmp;
+    if (lseek(fd, idx * sizeof(struct Node), SEEK_SET) == -1) {
+        close(fd);
+        exit(1);
+    }
+    read_struct(fd, &tmp, is_le);
+
+    inorder_traversal(fd, tmp.right_idx, is_le);
+    printf("%d\n", tmp.key);
+    inorder_traversal(fd, tmp.left_idx, is_le);
+
+    return;
+}
+
+int
+main(int argc, char **argv)
+{
+    if (argc != 2) {
+        return 1;
+    }
+
+    int test = 1;
+    int is_le = 0;
+    if (*(char *) &test == 1) {
+        is_le = 1;
+    }
+
+    int fd = open(argv[1], O_RDONLY);
+    if (fd == -1) {
+        return 1;
+    }
+
+    inorder_traversal(fd, -1, is_le);
+    putchar('\n');
+    close(fd);
+
+    return 0;
+}