[PATCH 08/52] video: Add a way to write a partial string to the console

[Simon Glass]

When writing multiple lines of text we need to be able to control which
text goes on each line. Add a new vidconsole_put_stringn() function to
help with this.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 drivers/video/vidconsole-uclass.c | 13 ++++++++++---
 include/video_console.h           | 17 +++++++++++++++++
 test/dm/video.c                   |  3 ++-
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/drivers/video/vidconsole-uclass.c b/drivers/video/vidconsole-uclass.c
index 3259bd2ef7d..fa329bd1b37 100644
--- a/drivers/video/vidconsole-uclass.c
+++ b/drivers/video/vidconsole-uclass.c
@@ -508,12 +508,14 @@ int vidconsole_put_char(struct udevice *dev, char ch)
 	return 0;
 }
 
-int vidconsole_put_string(struct udevice *dev, const char *str)
+int vidconsole_put_stringn(struct udevice *dev, const char *str, int maxlen)
 {
-	const char *s;
+	const char *s, *end = NULL;
 	int ret;
 
-	for (s = str; *s; s++) {
+	if (maxlen != -1)
+		end = str + maxlen;
+	for (s = str; *s && (maxlen == -1 || s < end); s++) {
 		ret = vidconsole_put_char(dev, *s);
 		if (ret)
 			return ret;
@@ -522,6 +524,11 @@ int vidconsole_put_string(struct udevice *dev, const char *str)
 	return 0;
 }
 
+int vidconsole_put_string(struct udevice *dev, const char *str)
+{
+	return vidconsole_put_stringn(dev, str, -1);
+}
+
 static void vidconsole_putc(struct stdio_dev *sdev, const char ch)
 {
 	struct udevice *dev = sdev->priv;
diff --git a/include/video_console.h b/include/video_console.h
index 1bb265dc9da..e4fc776e2d3 100644
--- a/include/video_console.h
+++ b/include/video_console.h
@@ -499,6 +499,23 @@ int vidconsole_entry_start(struct udevice *dev);
  */
 int vidconsole_put_char(struct udevice *dev, char ch);
 
+/**
+ * vidconsole_put_stringn() - Output part of a string to the current console pos
+ *
+ * Outputs part of a string to the console and advances the cursor. This
+ * function handles wrapping to new lines and scrolling the console. Special
+ * characters are handled also: \n, \r, \b and \t.
+ *
+ * The device always starts with the cursor at position 0,0 (top left). It
+ * can be adjusted manually using vidconsole_position_cursor().
+ *
+ * @dev:	Device to adjust
+ * @str:	String to write
+ * @maxlen:	Maximum chars to output, or -1 for all
+ * Return: 0 if OK, -ve on error
+ */
+int vidconsole_put_stringn(struct udevice *dev, const char *str, int maxlen);
+
 /**
  * vidconsole_put_string() - Output a string to the current console position
  *
diff --git a/test/dm/video.c b/test/dm/video.c
index c1b2a502b47..a9b2482631f 100644
--- a/test/dm/video.c
+++ b/test/dm/video.c
@@ -607,7 +607,8 @@ static int dm_test_video_truetype(struct unit_test_state *uts)
 	ut_assertok(video_get_nologo(uts, &dev));
 	ut_assertok(uclass_get_device(UCLASS_VIDEO_CONSOLE, 0, &con));
 	vidconsole_put_string(con, test_string);
-	ut_asserteq(12174, compress_frame_buffer(uts, dev, false));
+	vidconsole_put_stringn(con, test_string, 30);
+	ut_asserteq(13184, compress_frame_buffer(uts, dev, false));
 	ut_assertok(check_copy_frame_buffer(uts, dev));
 
 	return 0;
-- 
2.43.0