libsmartcols: add scols_line_move_cells()

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

3 files changed, 50 insertions, 3 deletions

diff --git a/libsmartcols/src/line.c b/libsmartcols/src/line.c
index 454882094..1c3141a16 100644
--- a/libsmartcols/src/line.c
+++ b/libsmartcols/src/line.c
@@ -146,6 +146,33 @@ int scols_line_alloc_cells(struct libscols_line *ln, size_t n)
 	return 0;
 }
 
+int scols_line_move_cells(struct libscols_line *ln, size_t newn, size_t oldn)
+{
+	struct libscols_cell ce;
+
+	if (!ln || newn >= ln->ncells || oldn >= ln->ncells)
+		return -EINVAL;
+	if (oldn == newn)
+		return 0;
+
+	DBG(LINE, ul_debugobj(ln, "move cells[%zu] -> cells[%zu]", oldn, newn));
+
+	/* remember data from old position */
+	memcpy(&ce, &ln->cells[oldn], sizeof(struct libscols_cell));
+
+	/* remove from old position */
+	memmove(ln->cells + oldn, ln->cells + oldn + 1,
+			(ln->ncells - oldn) * sizeof(struct libscols_cell));
+
+	/* create a space for new position */
+	memmove(ln->cells + newn + 1, ln->cells + newn,
+		(ln->ncells - newn) * sizeof(struct libscols_cell));
+
+	/* copy original data to new position */
+	memcpy(&ln->cells[newn], &ce, sizeof(struct libscols_cell));
+	return 0;
+}
+
 /**
  * scols_line_set_userdata:
  * @ln: a pointer to a struct libscols_line instance
diff --git a/libsmartcols/src/smartcolsP.h b/libsmartcols/src/smartcolsP.h
index 2a76048e1..0ce969bab 100644
--- a/libsmartcols/src/smartcolsP.h
+++ b/libsmartcols/src/smartcolsP.h
@@ -67,6 +67,7 @@ struct libscols_cell {
 	int	flags;
 };
 
+extern int scols_line_move_cells(struct libscols_line *ln, size_t newn, size_t oldn);
 
 /*
  * Table column
diff --git a/libsmartcols/src/table.c b/libsmartcols/src/table.c
index 84c0f6a25..3672114b2 100644
--- a/libsmartcols/src/table.c
+++ b/libsmartcols/src/table.c
@@ -268,18 +268,37 @@ int scols_table_move_column(struct libscols_table *tb,
 {
 	struct list_head *head;
 	struct libscols_iter itr;
-	size_t n = 0;
+	struct libscols_column *p;
+	struct libscols_line *ln;
+	size_t n = 0, oldseq;
+
+	if (!tb || !cl)
+		return -EINVAL;
+
+	if (pre && pre->seqnum + 1 == cl->seqnum)
+		return 0;
+	if (pre == NULL && cl->seqnum == 0)
+		return 0;
+
+	DBG(TAB, ul_debugobj(tb, "move column %zu behind %zu",
+				cl->seqnum, pre? pre->seqnum : 0));
 
 	list_del_init(&cl->cl_columns);		/* remove from old position */
 
 	head = pre ? &pre->cl_columns : &tb->tb_columns;
 	list_add(&cl->cl_columns, head);	/* add to the new place */
 
+	oldseq = cl->seqnum;
+
 	/* fix seq. numbers */
 	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
-	while (scols_table_next_column(tb, &itr, &cl) == 0)
-		cl->seqnum = n++;
+	while (scols_table_next_column(tb, &itr, &p) == 0)
+		p->seqnum = n++;
 
+	/* move data in lines */
+	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
+	while (scols_table_next_line(tb, &itr, &ln) == 0)
+		scols_line_move_cells(ln, cl->seqnum, oldseq);
 	return 0;
 }