ed: fix line insertion before current line

When text is inserted by insertLine() the lines following the
insertion are moved down and the insertion point is made the new
current line.  To avoid too much scanning of the linked list of
lines setCurNum() may use the position of the old current line to
determine the location of the new current line.

If the insertion point is before the old current line in the file
the latter will have been moved down, so its line pointer needs to
be adjusted.

(GitHub issue #431)

2 files changed, 25 insertions, 0 deletions

diff --git a/editors/ed.c b/editors/ed.c
index 8ec23d07f..e25179ddc 100644
--- a/editors/ed.c
+++ b/editors/ed.c
@@ -345,6 +345,10 @@ static int insertLine(int num, const char *data, int len)
         lp->prev->next = newLp;
         lp->prev = newLp;
 
+#if ENABLE_PLATFORM_MINGW32
+        if (num <= curNum)
+                curLine = curLine->prev;
+#endif
         lastNum++;
         dirty = TRUE;
         return setCurNum(num);
diff --git a/testsuite/ed.tests b/testsuite/ed.tests
new file mode 100755
index 000000000..475fdc244
--- /dev/null
+++ b/testsuite/ed.tests
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+. ./testing.sh
+
+# testing "test name" "command" "expected result" "file input" "stdin"
+
+testing "ed insert text before current line" \
+        "ed input" "8\n1\ntext\n2\n3\n4\n13\n" "1\n2\n3\n4\n" '2i
+text
+.
+,p
+w
+q
+'
+
+testing "ed read text before current line" \
+        "ed input" "8\n8\n1\n2\n1\n2\n3\n4\n3\n4\n16\n" "1\n2\n3\n4\n" '2r input
+,p
+w
+q
+'