patch 8.0.1755: MS-Windows: high unicode char received as two utf-16 words
Problem: MS-Windows GUI: high unicode char received as two utf-16 words.
Solution: Keep the first word until the second word is received. (Chris
Morgan, closes #2800)
diff --git a/src/gui_w32.c b/src/gui_w32.c
index 6596cf8..25fbe9f 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -494,9 +494,11 @@
static int s_x_pending;
static int s_y_pending;
static UINT s_kFlags_pending;
-static UINT s_wait_timer = 0; /* Timer for get char from user */
+static UINT s_wait_timer = 0; // Timer for get char from user
static int s_timed_out = FALSE;
-static int dead_key = 0; /* 0: no dead key, 1: dead key pressed */
+static int dead_key = 0; // 0: no dead key, 1: dead key pressed
+static UINT surrogate_pending_ch = 0; // 0: no surrogate pending,
+ // else a high surrogate
#ifdef FEAT_BEVAL_GUI
/* balloon-eval WM_NOTIFY_HANDLER */
@@ -708,6 +710,12 @@
* Convert Unicode character "ch" to bytes in "string[slen]".
* When "had_alt" is TRUE the ALT key was included in "ch".
* Return the length.
+ * Because the Windows API uses UTF-16, we have to deal with surrogate
+ * pairs; this is where we choose to deal with them: if "ch" is a high
+ * surrogate, it will be stored, and the length returned will be zero; the next
+ * char_to_string call will then include the high surrogate, decoding the pair
+ * of UTF-16 code units to a single Unicode code point, presuming it is the
+ * matching low surrogate.
*/
static int
char_to_string(int ch, char_u *string, int slen, int had_alt)
@@ -718,8 +726,27 @@
WCHAR wstring[2];
char_u *ws = NULL;
- wstring[0] = ch;
- len = 1;
+ if (surrogate_pending_ch != 0)
+ {
+ /* We don't guarantee ch is a low surrogate to match the high surrogate
+ * we already have; it should be, but if it isn't, tough luck. */
+ wstring[0] = surrogate_pending_ch;
+ wstring[1] = ch;
+ surrogate_pending_ch = 0;
+ len = 2;
+ }
+ else if (ch >= 0xD800 && ch <= 0xDBFF) /* high surrogate */
+ {
+ /* We don't have the entire code point yet, only the first UTF-16 code
+ * unit; so just remember it and use it in the next call. */
+ surrogate_pending_ch = ch;
+ return 0;
+ }
+ else
+ {
+ wstring[0] = ch;
+ len = 1;
+ }
/* "ch" is a UTF-16 character. Convert it to a string of bytes. When
* "enc_codepage" is non-zero use the standard Win32 function,
@@ -743,7 +770,6 @@
}
else
{
- len = 1;
ws = utf16_to_enc(wstring, &len);
if (ws == NULL)
len = 0;