libbb/lineedit: add support for preserving "broken" (non-unicode) chars

Signed-off-by: Tomas Heinrich <heinrich.tomas@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 51 insertions, 11 deletions

diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index dc90846f9..622f9ddfc 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -68,7 +68,7 @@
 
 #undef CHAR_T
 #if ENABLE_UNICODE_SUPPORT
-# define BB_NUL L'\0'
+# define BB_NUL ((wchar_t)0)
 # define CHAR_T wchar_t
 static bool BB_isspace(CHAR_T c) { return ((unsigned)c < 256 && isspace(c)); }
 # if ENABLE_FEATURE_EDITING_VI
@@ -92,6 +92,14 @@ static bool BB_ispunct(CHAR_T c) { return ((unsigned)c < 256 && ispunct(c)); }
 #endif
 
 
+# if ENABLE_UNICODE_PRESERVE_BROKEN
+#  define unicode_mark_inv_wchar(wc)   ((wc) | 0x20000000)
+#  define unicode_is_inv_wchar(wc)     ((wc) & 0x20000000)
+# else
+#  define unicode_is_inv_wchar(wc)     0
+# endif
+
+
 enum {
         /* We use int16_t for positions, need to limit line len */
         MAX_LINELEN = CONFIG_FEATURE_EDITING_MAX_LEN < 0x7ff0
@@ -208,24 +216,58 @@ static size_t load_string(const char *src, int maxsize)
         ssize_t len = mbstowcs(command_ps, src, maxsize - 1);
         if (len < 0)
                 len = 0;
-        command_ps[len] = L'\0';
+        command_ps[len] = 0;
         return len;
 }
-static size_t save_string(char *dst, int maxsize)
+static unsigned save_string(char *dst, unsigned maxsize)
 {
+#if !ENABLE_UNICODE_PRESERVE_BROKEN
         ssize_t len = wcstombs(dst, command_ps, maxsize - 1);
         if (len < 0)
                 len = 0;
         dst[len] = '\0';
         return len;
+#else
+        unsigned dstpos = 0;
+        unsigned srcpos = 0;
+
+        maxsize--;
+        while (dstpos < maxsize) {
+                wchar_t wc;
+                int n = srcpos;
+                while ((wc = command_ps[srcpos]) != 0
+                    && !unicode_is_inv_wchar(wc)
+                ) {
+                        srcpos++;
+                }
+                command_ps[srcpos] = 0;
+                n = wcstombs(dst + dstpos, command_ps + n, maxsize - dstpos);
+                if (n < 0) /* should not happen */
+                        break;
+                dstpos += n;
+                if (wc == 0) /* usually is */
+                        break;
+                /* We do have invalid byte here! */
+                command_ps[srcpos] = wc; /* restore it */
+                srcpos++;
+                if (dstpos == maxsize)
+                        break;
+                dst[dstpos++] = (char) wc;
+        }
+        dst[dstpos] = '\0';
+        return dstpos;
+#endif
 }
 /* I thought just fputwc(c, stdout) would work. But no... */
 static void BB_PUTCHAR(wchar_t c)
 {
         char buf[MB_CUR_MAX + 1];
         mbstate_t mbst = { 0 };
-        ssize_t len = wcrtomb(buf, c, &mbst);
+        ssize_t len;
 
+        if (unicode_is_inv_wchar(c))
+                c = CONFIG_SUBST_WCHAR;
+        len = wcrtomb(buf, c, &mbst);
         if (len > 0) {
                 buf[len] = '\0';
                 fputs(buf, stdout);
@@ -238,7 +280,7 @@ static size_t load_string(const char *src, int maxsize)
         return strlen(command_ps);
 }
 # if ENABLE_FEATURE_TAB_COMPLETION
-static void save_string(char *dst, int maxsize)
+static void save_string(char *dst, unsigned maxsize)
 {
         safe_strncpy(dst, command_ps, maxsize);
 }
@@ -1719,13 +1761,11 @@ static int lineedit_read_key(char *read_key_buffer)
  pushback:
                                 /* Invalid sequence. Save all "bad bytes" except first */
                                 read_key_ungets(read_key_buffer, unicode_buf + 1, unicode_idx - 1);
-                                /*
-                                 * ic = unicode_buf[0] sounds even better, but currently
-                                 * this does not work: wchar_t[] -> char[] conversion
-                                 * when lineedit finishes mangles such "raw bytes"
-                                 * (by misinterpreting them as unicode chars):
-                                 */
+# if !ENABLE_UNICODE_PRESERVE_BROKEN
                                 ic = CONFIG_SUBST_WCHAR;
+# else
+                                ic = unicode_mark_inv_wchar(unicode_buf[0]);
+# endif
                         } else {
                                 /* Valid unicode char, return its code */
                                 ic = wc;