Optimize DISK I/O Rate precision and add shading for clearer display

Row.c

@@ -468,28 +468,49 @@ void Row_printRate(RichString* str, double rate, bool coloring) {
    }
 
    if (!isNonnegative(rate)) {
-      RichString_appendAscii(str, shadowColor, "        N/A ");
-   } else if (rate < 0.005) {
-      int len = snprintf(buffer, sizeof(buffer), "%7.2f B/s ", rate);
-      RichString_appendnAscii(str, shadowColor, buffer, len);
+      RichString_appendAscii(str, shadowColor, "     N/A ");
    } else if (rate < ONE_K) {
-      int len = snprintf(buffer, sizeof(buffer), "%7.2f B/s ", rate);
-      RichString_appendnAscii(str, baseColor, buffer, len);
-   } else if (rate < ONE_M) {
-      int len = snprintf(buffer, sizeof(buffer), "%7.2f K/s ", rate / ONE_K);
-      RichString_appendnAscii(str, baseColor, buffer, len);
-   } else if (rate < ONE_G) {
-      int len = snprintf(buffer, sizeof(buffer), "%7.2f M/s ", rate / ONE_M);
-      RichString_appendnAscii(str, megabytesColor, buffer, len);
-   } else if (rate < ONE_T) {
-      int len = snprintf(buffer, sizeof(buffer), "%7.2f G/s ", rate / ONE_G);
-      RichString_appendnAscii(str, largeNumberColor, buffer, len);
-   } else if (rate < ONE_P) {
-      int len = snprintf(buffer, sizeof(buffer), "%7.2f T/s ", rate / ONE_T);
-      RichString_appendnAscii(str, largeNumberColor, buffer, len);
+      int len = snprintf(buffer, sizeof(buffer), "%4.0f B/s ", rate);
+      RichString_appendnAscii(str, shadowColor, buffer, len);
    } else {
-      int len = snprintf(buffer, sizeof(buffer), "%7.2f P/s ", rate / ONE_P);
-      RichString_appendnAscii(str, largeNumberColor, buffer, len);
+      size_t unitPrefixIndex = 0;
+      do {
+         if (unitPrefixIndex > ARRAYSIZE(unitPrefixes)-1) {
+            int len = snprintf(buffer, sizeof(buffer), "     INF ");
+            RichString_appendnAscii(str, largeNumberColor, buffer, len);
+            return;
+         }
+         unitPrefixIndex++;
+         rate /= ONE_K;
+      } while (rate >= ONE_K);
+
+      unitPrefixIndex--; // unitPrefixes starts from K
+
+      int precision = 0;
+      if (rate <= 999.9) {
+         if (rate <= 99.99) {
+            if (rate <= 9.999)
+               precision = 3;
+            else
+               precision = 2;
+         }
+         else
+            precision = 1;
+      }
+
+      if (precision < 3) {
+         double upper_limit = (precision < 2) ? ((precision < 1) ? 1000 : 100) : 10;
+         if (rate < upper_limit) {
+            rate = upper_limit;
+         }
+      }
+
+      int len = snprintf(buffer, sizeof(buffer), "%5.*f", precision, rate);
+      int rateDisplayColor = (unitPrefixIndex < 2) ? ((!unitPrefixIndex) ? baseColor : megabytesColor) : largeNumberColor;
+      RichString_appendnAscii(str, rateDisplayColor, buffer, len);
+      len = snprintf(buffer, sizeof(buffer), "%c/s ", unitPrefixes[unitPrefixIndex]);
+      RichString_appendnAscii(str, shadowColor, buffer, len);
+
    }
 }