libsmartcols: add iterator

Signed-off-by: Karel Zak <kzak@redhat.com>

4 files changed, 97 insertions, 0 deletions

diff --git a/libsmartcols/src/Makemodule.am b/libsmartcols/src/Makemodule.am
index f942b6789..3dbac9ca1 100644
--- a/libsmartcols/src/Makemodule.am
+++ b/libsmartcols/src/Makemodule.am
@@ -9,6 +9,7 @@ libsmartcols_la_SOURCES= \
 	include/list.h \
 	\
 	libsmartcols/src/smartcolsP.h \
+	libsmartcols/src/iter.c \
 	$(smartcolsinc_HEADERS)
 
 nodist_libsmartcols_la_SOURCES = libsmartcols/src/smartcolsP.h
diff --git a/libsmartcols/src/iter.c b/libsmartcols/src/iter.c
new file mode 100644
index 000000000..d9b33da7c
--- /dev/null
+++ b/libsmartcols/src/iter.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2009-2014 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+
+/**
+ * SECTION: iter
+ * @title: Iterator
+ * @short_description: unified iterator
+ *
+ * The iterator keeps the direction and the last position
+ * for access to the internal library tables/lists.
+ */
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "smartcolsP.h"
+
+/**
+ * scols_new_iter:
+ * @direction: SCOLS_INTER_{FOR,BACK}WARD direction
+ *
+ * Returns: newly allocated generic libmount iterator.
+ */
+struct libscols_iter *scols_new_iter(int direction)
+{
+	struct libscols_iter *itr = calloc(1, sizeof(*itr));
+	if (!itr)
+		return NULL;
+	itr->direction = direction;
+	return itr;
+}
+
+/**
+ * scols_free_iter:
+ * @itr: iterator pointer
+ *
+ * Deallocates the iterator.
+ */
+void scols_free_iter(struct libscols_iter *itr)
+{
+	free(itr);
+}
+
+/**
+ * scols_reset_iter:
+ * @itr: iterator pointer
+ * @direction: SCOLS_INTER_{FOR,BACK}WARD or -1 to keep the direction unchanged
+ *
+ * Resets the iterator.
+ */
+void scols_reset_iter(struct libscols_iter *itr, int direction)
+{
+	if (direction == -1)
+		direction = itr->direction;
+
+	memset(itr, 0, sizeof(*itr));
+	itr->direction = direction;
+}
+
+/**
+ * scols_iter_get_direction:
+ * @itr: iterator pointer
+ *
+ * Returns: SCOLS_INTER_{FOR,BACK}WARD
+ */
+int scols_iter_get_direction(struct libscols_iter *itr)
+{
+	return itr->direction;
+}
diff --git a/libsmartcols/src/libsmartcols.h.in b/libsmartcols/src/libsmartcols.h.in
index 84bbb825f..46a06a0ce 100644
--- a/libsmartcols/src/libsmartcols.h.in
+++ b/libsmartcols/src/libsmartcols.h.in
@@ -19,6 +19,20 @@ extern "C" {
 
 #define LIBSMARTCOLS_VERSION   "@LIBSMARTCOLS_VERSION@"
 
+struct libscols_iter;
+
+
+/* iter.c */
+enum {
+
+	SCOLS_ITER_FORWARD = 0,
+	SCOLS_ITER_BACKWARD
+};
+
+extern struct libscols_iter *scols_new_iter(int direction);
+extern void scols_free_iter(struct libscols_iter *itr);
+extern void scols_reset_iter(struct libscols_iter *itr, int direction);
+extern int scols_iter_get_direction(struct libscols_iter *itr);
 
 #ifdef __cplusplus
 }
diff --git a/libsmartcols/src/smartcolsP.h b/libsmartcols/src/smartcolsP.h
index fecf9e8c0..c42457580 100644
--- a/libsmartcols/src/smartcolsP.h
+++ b/libsmartcols/src/smartcolsP.h
@@ -24,4 +24,13 @@
 # define assert(x)
 #endif
 
+/*
+ * Generic iterator
+ */
+struct libscols_iter {
+	struct list_head        *p;		/* current position */
+	struct list_head        *head;		/* start position */
+	int			direction;	/* SCOLS_ITER_{FOR,BACK}WARD */
+};
+
 #endif /* _LIBSMARTCOLS_PRIVATE_H */