build system: introduce FEATURE_ASSUME_UNICODE

ls: use it. also do G trick. with UNICODE off:

function                                             old     new   delta
ls_main                                              843     871     +28
show_color                                             1       -      -1
showdirs                                             500     497      -3
my_stat                                              100      97      -3
terminal_width                                         4       -      -4
tabstops                                               4       -      -4
status                                               122     118      -4
static.dotdir                                          4       -      -4
current_time_t                                         4       -      -4
all_fmt                                                4       -      -4
------------------------------------------------------------------------------
(add/remove: 0/6 grow/shrink: 1/3 up/down: 28/-31)             Total: -3 bytes

Also was tested with UNICODE on with glibc.

2 files changed, 99 insertions, 62 deletions

diff --git a/Config.in b/Config.in
index 0a7edf84c..e70caf5a1 100644
--- a/Config.in
+++ b/Config.in
@@ -21,6 +21,18 @@ config DESKTOP
           Select this only if you plan to use busybox on full-blown
           desktop machine with common Linux distro, not on an embedded box.
 
+config FEATURE_ASSUME_UNICODE
+        bool "Assume that 1:1 char/glyph correspondence is not true"
+        default n
+        help
+          This makes various applets aware that one byte is not
+          one character on screen.
+
+          Busybox aims to eventually work correctly with Unicode displays.
+          Any older encodings are not guaranteed to work.
+          Probably by the time when busybox will be fully Unicode-clean,
+          other encodings will be mainly of historic interest.
+
 choice
         prompt "Buffer allocation policy"
         default FEATURE_BUFFERS_USE_MALLOC
diff --git a/coreutils/ls.c b/coreutils/ls.c
index 985086634..7d33eae8d 100644
--- a/coreutils/ls.c
+++ b/coreutils/ls.c
@@ -31,6 +31,10 @@
 
 #include "libbb.h"
 
+#if ENABLE_FEATURE_ASSUME_UNICODE
+#include <wchar.h>
+#endif
+
 /* This is a NOEXEC applet. Be very careful! */
 
 
@@ -114,18 +118,6 @@ SPLIT_SUBDIR    = 2,
 #define ATTR(mode)      ("\00\00\01\00\01\00\01\00"\
                          "\00\00\01\00\01\00\00\01" [TYPEINDEX(mode)])
 
-/* colored LS support by JaWi, janwillem.janssen@lxtreme.nl */
-#if ENABLE_FEATURE_LS_COLOR
-static smallint show_color;
-/* long option entry used only for --color, which has no short option
- * equivalent */
-static const char ls_color_opt[] ALIGN1 =
-        "color\0" Optional_argument "\xff" /* no short equivalent */
-        ;
-#else
-enum { show_color = 0 };
-#endif
-
 /*
  * a directory entry and its stat info are stored here
  */
@@ -137,25 +129,68 @@ struct dnode {                  /* the basic node */
         USE_SELINUX(security_context_t sid;)
         struct dnode *next;     /* point at the next node */
 };
-typedef struct dnode dnode_t;
 
 static struct dnode **list_dir(const char *);
 static struct dnode **dnalloc(int);
-static int list_single(struct dnode *);
+static int list_single(const struct dnode *);
 
-static unsigned all_fmt;
 
+struct globals {
+#if ENABLE_FEATURE_LS_COLOR
+        smallint show_color;
+#endif
+        smallint exit_failure;
+        unsigned all_fmt;
+#if ENABLE_FEATURE_AUTOWIDTH
+        unsigned tabstops; // = COLUMN_GAP;
+        unsigned terminal_width; // = TERMINAL_WIDTH;
+#endif
+#if ENABLE_FEATURE_LS_TIMESTAMPS
+        /* Do time() just once. Saves one syscall per file for "ls -l" */
+        time_t current_time_t;
+#endif
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#if ENABLE_FEATURE_LS_COLOR
+#define show_color     (G.show_color    )
+#else
+enum { show_color = 0 };
+#endif
+#define exit_failure   (G.exit_failure  )
+#define all_fmt        (G.all_fmt       )
 #if ENABLE_FEATURE_AUTOWIDTH
-static unsigned tabstops = COLUMN_GAP;
-static unsigned terminal_width = TERMINAL_WIDTH;
+#define tabstops       (G.tabstops      )
+#define terminal_width (G.terminal_width)
 #else
 enum {
         tabstops = COLUMN_GAP,
         terminal_width = TERMINAL_WIDTH,
 };
 #endif
+#define current_time_t (G.current_time_t)
+/* memset: we have to zero it out because of NOEXEC */
+#define INIT_G() { \
+        memset(&G, 0, sizeof(G)); \
+        tabstops = COLUMN_GAP; \
+        terminal_width = TERMINAL_WIDTH; \
+        USE_FEATURE_LS_TIMESTAMPS(time(&current_time_t);) \
+}
+
+
+#if ENABLE_FEATURE_ASSUME_UNICODE
+/* libbb candidate */
+static size_t mbstrlen(const char *string)
+{
+        size_t width = mbsrtowcs(NULL /*dest*/, &string,
+                                MAXINT(size_t) /*len*/, NULL /*state*/);
+        if (width == (size_t)-1)
+                return strlen(string);
+        return width;
+}
+#else
+#define mbstrlen(string) strlen(string)
+#endif
 
-static int status = EXIT_SUCCESS;
 
 static struct dnode *my_stat(const char *fullname, const char *name, int force_follow)
 {
@@ -171,7 +206,7 @@ static struct dnode *my_stat(const char *fullname, const char *name, int force_f
 #endif
                 if (stat(fullname, &dstat)) {
                         bb_simple_perror_msg(fullname);
-                        status = EXIT_FAILURE;
+                        exit_failure = 1;
                         return 0;
                 }
         } else {
@@ -182,7 +217,7 @@ static struct dnode *my_stat(const char *fullname, const char *name, int force_f
 #endif
                 if (lstat(fullname, &dstat)) {
                         bb_simple_perror_msg(fullname);
-                        status = EXIT_FAILURE;
+                        exit_failure = 1;
                         return 0;
                 }
         }
@@ -395,7 +430,7 @@ static void showfiles(struct dnode **dn, int nfiles)
         } else {
                 /* find the longest file name, use that as the column width */
                 for (i = 0; i < nfiles; i++) {
-                        int len = strlen(dn[i]->name);
+                        int len = mbstrlen(dn[i]->name);
                         if (column_width < len)
                                 column_width = len;
                 }
@@ -494,7 +529,7 @@ static struct dnode **list_dir(const char *path)
         nfiles = 0;
         dir = warn_opendir(path);
         if (dir == NULL) {
-                status = EXIT_FAILURE;
+                exit_failure = 1;
                 return NULL;    /* could not open the dir */
         }
         while ((entry = readdir(dir)) != NULL) {
@@ -538,13 +573,7 @@ static struct dnode **list_dir(const char *path)
 }
 
 
-#if ENABLE_FEATURE_LS_TIMESTAMPS
-/* Do time() just once. Saves one syscall per file for "ls -l" */
-/* Initialized in main() */
-static time_t current_time_t;
-#endif
-
-static int list_single(struct dnode *dn)
+static int list_single(const struct dnode *dn)
 {
         int i, column = 0;
 
@@ -658,7 +687,12 @@ static int list_single(struct dnode *dn)
                                                 fgcolor(info.st_mode));
                         }
 #endif
+#if ENABLE_FEATURE_ASSUME_UNICODE
+                        printf("%s", dn->name);
+                        column += mbstrlen(dn->name);
+#else
                         column += printf("%s", dn->name);
+#endif
                         if (show_color) {
                                 printf("\033[0m");
                         }
@@ -701,6 +735,7 @@ static int list_single(struct dnode *dn)
         return column;
 }
 
+
 /* "[-]Cadil1", POSIX mandated options, busybox always supports */
 /* "[-]gnsx", POSIX non-mandated options, busybox always supports */
 /* "[-]Ak" GNU options, busybox always supports */
@@ -779,11 +814,18 @@ static const unsigned opt_flags[] = {
 };
 
 
-/* THIS IS A "SAFE" APPLET, main() MAY BE CALLED INTERNALLY FROM SHELL */
-/* BE CAREFUL! */
+/* colored LS support by JaWi, janwillem.janssen@lxtreme.nl */
+#if ENABLE_FEATURE_LS_COLOR
+/* long option entry used only for --color, which has no short option
+ * equivalent */
+static const char ls_color_opt[] ALIGN1 =
+        "color\0" Optional_argument "\xff" /* no short equivalent */
+        ;
+#endif
+
 
 int ls_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int ls_main(int argc, char **argv)
+int ls_main(int argc ATTRIBUTE_UNUSED, char **argv)
 {
         struct dnode **dnd;
         struct dnode **dnf;
@@ -791,18 +833,13 @@ int ls_main(int argc, char **argv)
         struct dnode *dn;
         struct dnode *cur;
         unsigned opt;
-        int nfiles = 0;
+        int nfiles;
         int dnfiles;
         int dndirs;
-        int oi;
-        int ac;
         int i;
-        char **av;
         USE_FEATURE_LS_COLOR(char *color_opt;)
 
-#if ENABLE_FEATURE_LS_TIMESTAMPS
-        time(&current_time_t);
-#endif
+        INIT_G();
 
         all_fmt = LIST_SHORT |
                 (ENABLE_FEATURE_LS_SORTFILES * (SORT_NAME | SORT_FORWARD));
@@ -883,39 +920,27 @@ int ls_main(int argc, char **argv)
         if (!(all_fmt & STYLE_MASK))
                 all_fmt |= (isatty(STDOUT_FILENO) ? STYLE_COLUMNS : STYLE_SINGLE);
 
-        /*
-         * when there are no cmd line args we have to supply a default "." arg.
-         * we will create a second argv array, "av" that will hold either
-         * our created "." arg, or the real cmd line args.  The av array
-         * just holds the pointers- we don't move the date the pointers
-         * point to.
-         */
-        ac = argc - optind;     /* how many cmd line args are left */
-        if (ac < 1) {
-                static const char *const dotdir[] = { "." };
-
-                av = (char **) dotdir;
-                ac = 1;
-        } else {
-                av = argv + optind;
-        }
+        argv += optind;
+        if (!argv[0])
+                *--argv = (char*)".";
 
-        /* now, everything is in the av array */
-        if (ac > 1)
-                all_fmt |= DISP_DIRNAME;        /* 2 or more items? label directories */
+        if (argv[1])
+                all_fmt |= DISP_DIRNAME; /* 2 or more items? label directories */
 
         /* stuff the command line file names into a dnode array */
         dn = NULL;
-        for (oi = 0; oi < ac; oi++) {
+        nfiles = 0;
+        do {
                 /* ls w/o -l follows links on command line */
-                cur = my_stat(av[oi], av[oi], !(all_fmt & STYLE_LONG));
+                cur = my_stat(*argv, *argv, !(all_fmt & STYLE_LONG));
+                argv++;
                 if (!cur)
                         continue;
                 cur->allocated = 0;
                 cur->next = dn;
                 dn = cur;
                 nfiles++;
-        }
+        } while (*argv);
 
         /* now that we know how many files there are
          * allocate memory for an array to hold dnode pointers
@@ -950,5 +975,5 @@ int ls_main(int argc, char **argv)
         }
         if (ENABLE_FEATURE_CLEAN_UP)
                 dfree(dnp, nfiles);
-        return status;
+        return (exit_failure == 0);
 }