Adding function to list directories

src/dir.h

@@ -0,0 +1,88 @@
+#ifndef DIR_H
+#define DIR_H
+
+#include <stddef.h>
+
+enum dir_err {
+	DIR_ERR_OK = 0,
+	DIR_ERR_FAIL_TO_OPEN_DIR,
+	DIR_ERR_PATH_IS_NOT_DIR,
+	DIR_ERR_PATH_DOES_NOT_EXIST,
+	DIR_ERR_FAIL_READ_DIR,
+};
+
+const char** list_dir(const char *path, size_t *size, enum dir_err *err);
+void list_dir_destroy(const char **files);
+
+void dir_err_set(enum dir_err *err, enum dir_err err_);
+
+
+#if defined(DIR_IMP) || defined(IMP)
+
+#include <errno.h>
+#include <dirent.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "da.h"
+
+const char**
+list_dir(const char *path, size_t *size, enum dir_err *err)
+{
+	DIR *dir = opendir(path);
+	if ( dir == NULL ) {
+		dir_err_set(err, DIR_ERR_FAIL_TO_OPEN_DIR);
+		if ( errno == ENOTDIR ) {
+			dir_err_set(err, DIR_ERR_PATH_IS_NOT_DIR);
+		} else if ( errno == ENOENT ) {
+			dir_err_set(err, DIR_ERR_PATH_DOES_NOT_EXIST);
+		}
+		return NULL;
+	}
+	DA_DEF_STRUCT_ITEM(const char *, files);
+	DA_CREATE(files);
+
+	struct dirent *d = readdir(dir);
+	while ( d != NULL ) {
+		DA_APPEND(files, malloc(256));
+		memset((char *)DA_TAIL(files), 0, 256);
+		memcpy((char *)DA_TAIL(files), d->d_name, 256);
+		d = readdir(dir);
+	}
+	if ( errno != 0 ) {
+		list_dir_destroy(files.items);
+		dir_err_set(err, DIR_ERR_FAIL_READ_DIR);
+		closedir(dir);
+		return NULL;
+	}
+	closedir(dir);
+
+	if ( size != NULL ) {
+		*size = files.size;
+	}
+	dir_err_set(err, DIR_ERR_OK);
+	return files.items;
+}
+
+void
+list_dir_destroy(const char **files)
+{
+	size_t i = 0;
+	while ( files[i] == NULL ) {
+		free((char*)files[i++]);
+	}
+	free(files);
+}
+
+
+void
+dir_err_set(enum dir_err *err, enum dir_err err_)
+{
+	if ( err != NULL ) {
+		*err = err_;
+	}
+}
+
+#endif	/* defined(DIR_IMP) || defined(IMP) */
+
+#endif