autodetect unicode, and fallback to ACS scancodes on failure

this is fairly ugly - we use a hidden ncurses function to detect
unicode (but at least we don't reimplement it), then we mess around
with the character arrays to display the rights symbols

i am not sure i like this, but i prefer to braindump than to stall, so
let's move forward.

diff --git a/src/oping.c b/src/oping.c
index 068c55d..0cb084f 100644 (file)
--- a/src/oping.c
+++ b/src/oping.c
@@ -82,6 +82,11 @@
 # define _X_OPEN_SOURCE_EXTENDED
 # include <ncursesw/ncurses.h>
 
+/* some evilness: ncurses knows how to detect unicode, but won't
+   expose it, yet there's this function that does what we want, so we
+   steal it away from it */
+extern int    _nc_unicode_locale(void);
+
 # define OPING_GREEN 1
 # define OPING_YELLOW 2
 # define OPING_RED 3
@@ -89,15 +94,31 @@
 # define OPING_YELLOW_HIST 5
 # define OPING_RED_HIST 6
 
-static char const * const hist_symbols[] = {
+static char const * const hist_symbols_utf8[] = {
        "▁", "▂", "▃", "▄", "▅", "▆", "▇", "█" };
-static size_t const hist_symbols_num = sizeof (hist_symbols)
-       / sizeof (hist_symbols[0]);
-
-static int const hist_colors[] = {
+static size_t const hist_symbols_utf8_num = sizeof (hist_symbols_utf8)
+       / sizeof (hist_symbols_utf8[0]);
+
+/* scancodes for 6 levels of horizontal bars, ncurses-specific */
+/* those are not the usual constants because those are not constant */
+static int const hist_symbols_acs[] = {
+       115, /* ACS_S9 "⎽" */
+       114, /* ACS_S7 "⎼" */
+       113, /* ACS_S5 "─" */
+       112, /* ACS_S3 "⎻" */
+       111  /* ACS_S1 "⎺" */
+};
+static size_t const hist_symbols_acs_num = sizeof (hist_symbols_acs)
+       / sizeof (hist_symbols_acs[0]);
+
+/* use different colors without a background for scancodes */
+static int const hist_colors_utf8[] = {
        OPING_GREEN_HIST, OPING_YELLOW_HIST, OPING_RED_HIST };
-static size_t const hist_colors_num = sizeof (hist_colors)
-       / sizeof (hist_colors[0]);
+static int const hist_colors_acs[] = {
+       OPING_GREEN, OPING_YELLOW, OPING_RED };
+/* assuming that both arrays are the same size */
+static size_t const hist_colors_num = sizeof (hist_colors_utf8)
+       / sizeof (hist_colors_utf8[0]);
 #endif
 
 #include "oping.h"
@@ -619,6 +640,9 @@ static int update_prettyping_graph (ping_context_t *ctx, /* {{{ */
 {
        int color = OPING_RED;
        char const *symbol = "!";
+       int symbolc = '!';
+       size_t hist_symbols_num;
+       size_t index_symbols;
 
        int x_max;
        int x_pos;
@@ -626,12 +650,19 @@ static int update_prettyping_graph (ping_context_t *ctx, /* {{{ */
        x_max = getmaxx (ctx->window);
        x_pos = ((sequence - 1) % (x_max - 4)) + 2;
 
+       if (_nc_unicode_locale())
+       {
+               hist_symbols_num = hist_symbols_utf8_num;
+       }
+       else {
+               hist_symbols_num = hist_symbols_acs_num;
+       }
+
        if (latency >= 0.0)
        {
                double ratio;
                size_t intensity;
                size_t index_colors;
-               size_t index_symbols;
 
                ratio = latency / PING_DEF_TTL;
                if (ratio > 1) {
@@ -643,19 +674,36 @@ static int update_prettyping_graph (ping_context_t *ctx, /* {{{ */
 
                index_colors = intensity / hist_symbols_num;
                assert (index_colors < hist_colors_num);
-               color = hist_colors[index_colors];
 
                index_symbols = intensity % hist_symbols_num;
-               symbol = hist_symbols[index_symbols];
-       }
+               if (_nc_unicode_locale())
+               {
+                       color = hist_colors_utf8[index_colors];
+                       symbol = hist_symbols_utf8[index_symbols];
+               }
+               else
+               {
+                       color = hist_colors_acs[index_colors];
+                       symbolc = hist_symbols_acs[index_symbols] | A_ALTCHARSET;
+               }
+        }
        else /* if (!(latency >= 0.0)) */
                wattron (ctx->window, A_BOLD);
 
        wattron (ctx->window, COLOR_PAIR(color));
-       mvwprintw (ctx->window,
-                       /* y = */ 3,
-                       /* x = */ x_pos,
-                       symbol);
+       if (_nc_unicode_locale())
+       {
+               mvwprintw (ctx->window,
+                          /* y = */ 3,
+                          /* x = */ x_pos,
+                          symbol);
+       }
+       else {
+               mvwaddch (ctx->window,
+                         /* y = */ 3,
+                         /* x = */ x_pos,
+                         symbolc);
+       }
        wattroff (ctx->window, COLOR_PAIR(color));
 
        /* Use negation here to handle NaN correctly. */