libbb: introduce fputc_printable (from ed)

netstat: print control chars as ^C etc
vi: style fixlet

function                                             old     new   delta
fputc_printable                                        -     100    +100
unix_do_one                                          451     487     +36
printLines                                           258     190     -68
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/1 up/down: 136/-68)            Total: 68 bytes

5 files changed, 19 insertions, 22 deletions

diff --git a/editors/ed.c b/editors/ed.c
index cceff0c40..a569788ad 100644
--- a/editors/ed.c
+++ b/editors/ed.c
@@ -847,20 +847,8 @@ static int printLines(int num1, int num2, int expandFlag)
                         count--;
 
                 while (count-- > 0) {
-                        ch = *cp++;
-                        if (ch & 0x80) {
-                                fputs("M-", stdout);
-                                ch &= 0x7f;
-                        }
-                        if (ch < ' ') {
-                                bb_putchar('^');
-                                ch += '@';
-                        }
-                        if (ch == 0x7f) {
-                                bb_putchar('^');
-                                ch = '?';
-                        }
-                        bb_putchar(ch);
+                        ch = (unsigned char) *cp++;
+                        fputc_printable(ch | PRINTABLE_META, stdout);
                 }
 
                 fputs("$\n", stdout);
diff --git a/editors/vi.c b/editors/vi.c
index b6d4dcf0d..d8492fe74 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -899,7 +899,7 @@ static void colon(char *buf)
                         if (c_is_no_print) {
                                 c = '.';
                                 standout_start();
-                                }
+                        }
                         if (c == '\n') {
                                 write1("$\r");
                         } else if (c < ' ' || c == 127) {
diff --git a/include/libbb.h b/include/libbb.h
index 1da37edb2..f35f85c33 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -426,6 +426,11 @@ char *safe_strncpy(char *dst, const char *src, size_t size);
  * But potentially slow, don't use in one-billion-times loops */
 int bb_putchar(int ch);
 char *xasprintf(const char *format, ...) __attribute__ ((format (printf, 1, 2)));
+/* Prints unprintable chars ch as ^C or M-c to file
+ * (M-c is used only if ch is ORed with PRINTABLE_META),
+ * else it is printed as-is (except for ch = 0x9b) */
+enum { PRINTABLE_META = 0x100 };
+void fputc_printable(int ch, FILE *file);
 // gcc-4.1.1 still isn't good enough at optimizing it
 // (+200 bytes compared to macro)
 //static ALWAYS_INLINE
diff --git a/libbb/Kbuild b/libbb/Kbuild
index 6791299f2..c4aac95bb 100644
--- a/libbb/Kbuild
+++ b/libbb/Kbuild
@@ -65,6 +65,7 @@ lib-y += perror_msg_and_die.o
 lib-y += perror_nomsg.o
 lib-y += perror_nomsg_and_die.o
 lib-y += pidfile.o
+lib-y += printable.o
 lib-y += process_escape_sequence.o
 lib-y += procps.o
 lib-y += read.o
diff --git a/networking/netstat.c b/networking/netstat.c
index 29c2384a4..348abd8ad 100644
--- a/networking/netstat.c
+++ b/networking/netstat.c
@@ -349,13 +349,9 @@ static int unix_do_one(int nr, char *line)
         const char *ss_proto, *ss_state, *ss_type;
         char ss_flags[32];
 
-        /* TODO: currently we stop at first NUL byte. Is it a problem? */
-
         if (nr == 0)
                 return 0; /* skip header */
 
-        *strchrnul(line, '\n') = '\0';
-
         /* 2.6.15 may report lines like "... @/tmp/fam-user-^@^@^@^@^@^@^@..."
          * Other users report long lines filled by NUL bytes. 
          * (those ^@ are NUL bytes too). We see them as empty lines. */
@@ -443,9 +439,16 @@ static int unix_do_one(int nr, char *line)
                 strcat(ss_flags, "N ");
         strcat(ss_flags, "]");
 
-        printf("%-5s %-6ld %-11s %-10s %-13s %6lu %s\n",
-                ss_proto, refcnt, ss_flags, ss_type, ss_state, inode,
-                line + path_ofs);
+        printf("%-5s %-6ld %-11s %-10s %-13s %6lu ",
+                ss_proto, refcnt, ss_flags, ss_type, ss_state, inode
+                );
+
+        /* TODO: currently we stop at first NUL byte. Is it a problem? */
+        line += path_ofs;
+        *strchrnul(line, '\n') = '\0';
+        while (*line)
+                fputc_printable(*line++, stdout);
+        bb_putchar('\n');
         return 0;
 }