win32: add support for the euro currency symbol

The euro currency symbol was added to some OEM code pages.  See:

   https://www.aivosto.com/articles/charsets-codepages-dos.html

Add a configuration option (enabled by default) to support this.
When enabled:

- The read_key() function requests wide character key events.  This
  allows the euro symbol to be entered regardless of the console OEM
  code page, though it needs to be available in the ANSI code page.

- Conversions between OEM and ANSI code pages in winansi.c are
  modified to work around a bug in the Microsoft routines.

- If the OEM code page is 850 when BusyBox starts it's changed to
  858.  This is the only currently supported OEM code page.

Also, the shell read builtin is modified to use read_key() whenever
input is being taken from the console.

1 files changed, 21 insertions, 0 deletions

diff --git a/win32/termios.c b/win32/termios.c
index 7a107c5bd..fe6f0c546 100644
--- a/win32/termios.c
+++ b/win32/termios.c
@@ -6,7 +6,12 @@ int64_t FAST_FUNC read_key(int fd, char *buf UNUSED_PARAM, int timeout)
         INPUT_RECORD record;
         DWORD nevent_out, mode;
         int ret = -1;
+#if ENABLE_FEATURE_EURO
+        wchar_t uchar;
+        char achar;
+#else
         char *s;
+#endif
         int alt_pressed = FALSE;
         DWORD state;
 
@@ -22,7 +27,11 @@ int64_t FAST_FUNC read_key(int fd, char *buf UNUSED_PARAM, int timeout)
                         if (WaitForSingleObject(cin, timeout) != WAIT_OBJECT_0)
                                 goto done;
                 }
+#if ENABLE_FEATURE_EURO
+                if (!ReadConsoleInputW(cin, &record, 1, &nevent_out))
+#else
                 if (!ReadConsoleInput(cin, &record, 1, &nevent_out))
+#endif
                         goto done;
 
                 if (record.EventType != KEY_EVENT)
@@ -40,7 +49,11 @@ int64_t FAST_FUNC read_key(int fd, char *buf UNUSED_PARAM, int timeout)
                         alt_pressed = ((state & LEFT_ALT_PRESSED) != 0);
                 }
 
+#if ENABLE_FEATURE_EURO
+                if (!record.Event.KeyEvent.uChar.UnicodeChar) {
+#else
                 if (!record.Event.KeyEvent.uChar.AsciiChar) {
+#endif
                         if (alt_pressed) {
                                 switch (record.Event.KeyEvent.wVirtualKeyCode) {
                                 case VK_MENU:
@@ -91,11 +104,19 @@ int64_t FAST_FUNC read_key(int fd, char *buf UNUSED_PARAM, int timeout)
                         }
                         continue;
                 }
+#if ENABLE_FEATURE_EURO
+                uchar = record.Event.KeyEvent.uChar.UnicodeChar;
+                achar = uchar & 0x7f;
+                if (achar != uchar)
+                        WideCharToMultiByte(CP_ACP, 0, &uchar, 1, &achar, 1, NULL, NULL);
+                ret = achar;
+#else
                 if ( (record.Event.KeyEvent.uChar.AsciiChar & 0x80) == 0x80 ) {
                         s = &record.Event.KeyEvent.uChar.AsciiChar;
                         OemToCharBuff(s, s, 1);
                 }
                 ret = record.Event.KeyEvent.uChar.AsciiChar;
+#endif
                 break;
         }
  done: