Refactor catv. Move visible() from stty to libbb.

Fixes the following TODO:

  stty's visible() function and catv's guts are identical. Merge them into
  an appropriate libbb function.

Also makes catv behave exactly like coreutils' cat -v e.g. it'll print 'M-^I'
instead of 'M-   '.

function                                             old     new   delta
visible                                                -      70     +70
do_display                                           431     379     -52
catv_main                                            306     250     -56
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/2 up/down: 70/-108)           Total: -38 bytes

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/libbb/printable.c b/libbb/printable.c
index f6ada4904..9a423431e 100644
--- a/libbb/printable.c
+++ b/libbb/printable.c
@@ -32,3 +32,27 @@ void FAST_FUNC fputc_printable(int ch, FILE *file)
         }
         fputc(ch, file);
 }
+
+void FAST_FUNC visible(unsigned ch, char *buf, int flags)
+{
+        if (ch == '\t' && !(flags & VISIBLE_SHOW_TABS)) {
+                goto raw;
+        }
+        if (ch == '\n') {
+                if (flags & VISIBLE_ENDLINE)
+                        *buf++ = '$';
+        } else {
+                if (ch >= 128) {
+                        ch -= 128;
+                        *buf++ = 'M';
+                        *buf++ = '-';
+                }
+                if (ch < 32 || ch == 127) {
+                        *buf++ = '^';
+                        ch ^= 0x40;
+                }
+        }
+ raw:
+        *buf++ = ch;
+        *buf = '\0';
+}