src/oping.c: Improve comments.

Also remove dead code.

diff --git a/src/oping.c b/src/oping.c
index 3e735ff..a74cd42 100644 (file)
--- a/src/oping.c
+++ b/src/oping.c
@@ -167,17 +167,22 @@ typedef struct ping_context
 #endif
        /* The last n RTTs in the order they were sent. */
        double history_by_time[HISTORY_SIZE_MAX];
-       /* Current size of the history. This is a value between 0 and
-        * HISTORY_SIZE_MAX. */
+
+       /* Current number of entries in the history. This is a value between 0
+        * and HISTORY_SIZE_MAX. */
        size_t history_size;
+
+       /* Number "received" entries in the history, i.e. non-NAN entries. */
+       size_t history_received;
+
        /* Index of the next RTT to be written to history_by_time. This wraps
         * around to 0 once the histroty has grown to HISTORY_SIZE_MAX. */
        size_t history_index;
-       /* Number received replies, i.e. non-NAN entries. */
-       size_t history_received;
-       /* The last n RTTs sorted by value. timed out packets are sorted to the
-        * back. */
+
+       /* The last history_size RTTs sorted by value. timed out packets (NAN
+        * entries) are sorted to the back. */
        double history_by_value[HISTORY_SIZE_MAX];
+
        /* If set to true, history_by_value has to be re-calculated. */
        _Bool history_dirty;
 
@@ -282,10 +287,12 @@ static void clean_history (ping_context_t *ctx) /* {{{ */
        /* Copy all values from by_time to by_value. */
        memcpy (ctx->history_by_value, ctx->history_by_time,
                        sizeof (ctx->history_by_time));
+
        /* Sort all RTTs. */
        qsort (ctx->history_by_value, ctx->history_size, sizeof
                        (ctx->history_by_value[0]), compare_double);
 
+       /* Update the number of received RTTs. */
        ctx->history_received = 0;
        for (i = 0; i < ctx->history_size; i++)
                if (!isnan (ctx->history_by_value[i]))
@@ -302,6 +309,7 @@ static double percentile_to_latency (ping_context_t *ctx, /* {{{ */
 
        clean_history (ctx);
 
+       /* Not a single packet was received successfully. */
        if (ctx->history_received == 0)
                return NAN;
 
@@ -320,7 +328,7 @@ static double percentile_to_latency (ping_context_t *ctx, /* {{{ */
 } /* }}} double percentile_to_latency */
 
 #if USE_NCURSES
-static double latency_to_percentile (ping_context_t *ctx, /* {{{ */
+static double latency_to_ratio (ping_context_t *ctx, /* {{{ */
                double latency)
 {
        size_t low;
@@ -329,6 +337,7 @@ static double latency_to_percentile (ping_context_t *ctx, /* {{{ */
 
        clean_history (ctx);
 
+       /* Not a single packet was received successfully. */
        if (ctx->history_received == 0)
                return NAN;
 
@@ -340,6 +349,11 @@ static double latency_to_percentile (ping_context_t *ctx, /* {{{ */
        else if (latency >= ctx->history_by_value[high])
                return 100.0;
 
+       /* Do a binary search for the latency. This will work even when the
+        * exact latency is not in the array. If the latency is in the array
+        * multiple times, "low" will be set to the index of the last
+        * occurrence. The value at index "high" will be larger than the
+        * searched for latency (assured by the above "if" block. */
        while ((high - low) > 1)
        {
                index = (high + low) / 2;
@@ -358,8 +372,8 @@ static double latency_to_percentile (ping_context_t *ctx, /* {{{ */
        else
                index = high;
 
-       return (100.0 * ((double) (index + 1)) / ((double) ctx->history_received));
-} /* }}} double latency_to_percentile */
+       return (((double) (index + 1)) / ((double) ctx->history_received));
+} /* }}} double latency_to_ratio */
 #endif
 
 static double context_get_packet_loss (const ping_context_t *ctx) /* {{{ */
@@ -962,6 +976,8 @@ static int update_graph_prettyping (ping_context_t *ctx, /* {{{ */
                return (EINVAL);
        x_max -= 4;
 
+       /* Determine the first index in the history we need to draw
+        * the graph. */
        history_offset = 0;
        if (((size_t) x_max) < ctx->history_size)
        {
@@ -1481,29 +1497,16 @@ static void update_host_hook (pingobj_iter_t *iter, /* {{{ */
 #if USE_NCURSES
                if (has_colors () == TRUE)
                {
-                       double percentile;
+                       double ratio;
                        int color = OPING_GREEN;
 
-                       percentile = latency_to_percentile (context, latency);
-                       if (percentile < (100.0 * threshold_green))
-                               color = OPING_GREEN;
-                       else if (percentile < (100.0 * threshold_yellow))
-                               color = OPING_YELLOW;
-                       else
-                               color = OPING_RED;
-
-#if 0
-                       if ((ratio_this <= threshold_green)
-                                       || ((ratio_prev < threshold_green)
-                                               && (ratio_this > threshold_green)))
+                       ratio = latency_to_ratio (context, latency);
+                       if (ratio < threshold_green)
                                color = OPING_GREEN;
-                       else if ((ratio_this <= threshold_yellow)
-                                       || ((ratio_prev < threshold_yellow)
-                                               && (ratio_this > threshold_yellow)))
+                       else if (ratio < threshold_yellow)
                                color = OPING_YELLOW;
                        else
                                color = OPING_RED;
-#endif
 
                        HOST_PRINTF ("%zu bytes from %s (%s): icmp_seq=%u ttl=%i ",
                                        data_len, context->host, context->addr,