1 files changed, 70 insertions, 16 deletions

diff --git a/libbb/unicode.c b/libbb/unicode.c
index 39b173e9c..878af84bc 100644
--- a/libbb/unicode.c
+++ b/libbb/unicode.c
@@ -216,8 +216,6 @@ size_t FAST_FUNC mbstowcs(wchar_t *dest, const char *src, size_t n)
         return org_n - n;
 }
 
-#include "unicode_wcwidth.c"
-
 int FAST_FUNC iswspace(wint_t wc)
 {
         return (unsigned)wc <= 0x7f && isspace(wc);
@@ -233,6 +231,8 @@ int FAST_FUNC iswpunct(wint_t wc)
         return (unsigned)wc <= 0x7f && ispunct(wc);
 }
 
+#include "unicode_wcwidth.c"
+
 #endif /* Homegrown Unicode support */
 
 
@@ -251,8 +251,22 @@ char* FAST_FUNC unicode_cut_nchars(unsigned width, const char *src)
         char *dst;
         unsigned dst_len;
 
-        if (unicode_status != UNICODE_ON)
-                return xasprintf("%-*.*s", width, width, src);
+        if (unicode_status != UNICODE_ON) {
+                char *d = dst = xmalloc(width + 1);
+                while ((int)--width >= 0) {
+                        unsigned char c = *src;
+                        if (c == '\0') {
+                                do
+                                        *d++ = ' ';
+                                while ((int)--width >= 0);
+                                break;
+                        }
+                        *d++ = (c >= ' ' && c < 0x7f) ? c : '?';
+                        src++;
+                }
+                *d = '\0';
+                return dst;
+        }
 
         dst = NULL;
         dst_len = 0;
@@ -260,31 +274,64 @@ char* FAST_FUNC unicode_cut_nchars(unsigned width, const char *src)
                 int w;
                 wchar_t wc;
 
-                dst = xrealloc(dst, dst_len + 2 * MB_CUR_MAX);
 #if ENABLE_LOCALE_SUPPORT
                 {
                         mbstate_t mbst = { 0 };
                         ssize_t rc = mbsrtowcs(&wc, &src, 1, &mbst);
-                        if (rc <= 0) /* error, or end-of-string */
+                        /* If invalid sequence is seen: -1 is returned,
+                         * src points to the invalid sequence, errno = EILSEQ.
+                         * Else number of wchars (excluding terminating L'\0')
+                         * written to dest is returned.
+                         * If len (here: 1) non-L'\0' wchars stored at dest,
+                         * src points to the next char to be converted.
+                         * If string is completely converted: src = NULL.
+                         */
+                        if (rc == 0) /* end-of-string */
                                 break;
+                        if (rc < 0) { /* error */
+                                src++;
+                                goto subst;
+                        }
+                        if (!iswprint(wc))
+                                goto subst;
                 }
 #else
-                src = mbstowc_internal(&wc, src);
-                if (!src || wc == 0) /* error, or end-of-string */
-                        break;
+                {
+                        const char *src1 = mbstowc_internal(&wc, src);
+                        /* src = NULL: invalid sequence is seen,
+                         * else: wc is set, src is advanced to next mb char
+                         */
+                        if (src1) {/* no error */
+                                if (wc == 0) /* end-of-string */
+                                        break;
+                                src = src1;
+                        } else { /* error */
+                                src++;
+                                goto subst;
+                        }
+                }
 #endif
+                if (CONFIG_LAST_SUPPORTED_WCHAR && wc > CONFIG_LAST_SUPPORTED_WCHAR)
+                        goto subst;
                 w = wcwidth(wc);
-                if (w < 0) /* non-printable wchar */
-                        break;
+                if ((ENABLE_UNICODE_COMBINING_WCHARS && w < 0) /* non-printable wchar */
+                 || (!ENABLE_UNICODE_COMBINING_WCHARS && wc <= 0)
+                 || (!ENABLE_UNICODE_WIDE_WCHARS && wc > 1)
+                ) {
+ subst:
+                        wc = CONFIG_SUBST_WCHAR;
+                        w = 1;
+                }
                 width -= w;
-                if ((int)width < 0) { /* string is longer than width */
+                /* Note: if width == 0, we still may add more chars,
+                 * they may be zero-width or combining ones */
+                if ((int)width < 0) {
+                        /* can't add this wc, string would become longer than width */
                         width += w;
-                        while (width) {
-                                dst[dst_len++] = ' ';
-                                width--;
-                        }
                         break;
                 }
+
+                dst = xrealloc(dst, dst_len + MB_CUR_MAX);
 #if ENABLE_LOCALE_SUPPORT
                 {
                         mbstate_t mbst = { 0 };
@@ -294,7 +341,14 @@ char* FAST_FUNC unicode_cut_nchars(unsigned width, const char *src)
                 dst_len += wcrtomb_internal(&dst[dst_len], wc);
 #endif
         }
+
+        /* Pad to remaining width */
+        dst = xrealloc(dst, dst_len + width + 1);
+        while ((int)--width >= 0) {
+                dst[dst_len++] = ' ';
+        }
         dst[dst_len] = '\0';
+
         return dst;
 }