add fs abstraction

fs.c

@@ -0,0 +1,40 @@
+/*
+ * fs.c
+ *
+ *  Created on: 20.10.2017
+ *      Author: julian
+ */
+
+#include "fs.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+
+void path_join(struct path *p1, struct path *p2) {
+	size_t other = p2->len;
+
+	while(other) {
+		p1->entries = realloc(p1->entries, sizeof(const char*) * (p1->len+1));
+		if (p1->entries == NULL) {
+			// OUT OF MEM, oper incomplete
+			return;
+		}
+
+		p1->entries[p1->len] = strdup(p2->entries[p2->len - other]);
+
+		other--;
+		p1->len++;
+	}
+}
+
+void free_path(struct path * p) {
+	while(p->len) {
+		free(p->entries[p->len-1]);
+		p->len--;
+	}
+
+	// free the old array
+	free(p->entries);
+}
+

fs.h

@@ -0,0 +1,30 @@
+/*
+ * fs.h
+ *
+ *  Created on: 20.10.2017
+ *      Author: julian
+ */
+
+#ifndef FS_H_
+#define FS_H_
+
+#include <stddef.h>	// size_t
+
+struct path {
+	char ** entries;
+	size_t len;
+	int absolute:1;
+};
+
+
+extern void path_join(struct path *p1, struct path *p2);
+extern void free_path(struct path *p);
+extern void create_path(struct path * p, const char * fsPath);
+
+
+#include <stdio.h>
+
+// behaves like fopen, but uses the path struct as path
+extern FILE * path_fopen(struct path * p, const char * flags);
+
+#endif /* FS_H_ */

test_path.c

@@ -0,0 +1,74 @@
+/*
+ * test_path.c
+ *
+ *  Created on: 20.10.2017
+ *      Author: julian
+ */
+
+
+#include "tests.h"
+#include "fs.h"
+
+#include <string.h>
+#include <unistd.h>
+
+const char * reason_invalid_entry = "invalid entry";
+
+void test1() {
+	init("a/b/c");
+
+	struct path p = {};
+	create_path(&p, "a/b/c");
+	if (p.len < 3) {
+		fail("%d, not enough path splits", p.len);
+	}
+	if (p.absolute) {
+		fail("path should be relative");
+	}
+	if (strcmp(p.entries[0], "a") != 0) {
+		fail(reason_invalid_entry);
+	}
+	if (strcmp(p.entries[1], "b") != 0) {
+		fail(reason_invalid_entry);
+	}
+	if (strcmp(p.entries[2], "c") != 0) {
+		fail(reason_invalid_entry);
+	}
+
+	free_path(&p);
+	pass();
+}
+
+void test2() {
+	init("/a/b/c");
+
+	struct path p = {};
+	create_path(&p, "/a/b/c");
+	if (p.len != 3) {
+		fail("%d, not enough path splits", p.len);
+	}
+	if (!p.absolute) {
+		fail("path should be absolute");
+	}
+
+	if (strcmp(p.entries[0], "a") != 0) {
+		fail(reason_invalid_entry);
+	}
+	if (strcmp(p.entries[1], "b") != 0) {
+		fail(reason_invalid_entry);
+	}
+	if (strcmp(p.entries[2], "c") != 0) {
+		fail(reason_invalid_entry);
+	}
+
+	free_path(&p);
+	pass();
+}
+
+int main() {
+	init("test_path");
+	test1();
+	test2();
+	pass();
+}
+