custom formatter for numbers in 'pow' units format

include/util/format.hpp

@@ -1,9 +1,70 @@
 #pragma once
 
-#include <sstream>
+#include <fmt/format.h>
 
-namespace waybar::util {
+class pow_format {
+  public:
+    pow_format(long long val, std::string&& unit, bool binary = false):
+      val_(val), unit_(unit), binary_(binary) { };
 
-std::string pow_format(unsigned long long value, const std::string &unit, bool binary = false);
+    long long val_;
+    std::string unit_;
+    bool binary_;
+};
 
+
+namespace fmt {
+  template <>
+    struct formatter<pow_format> {
+      char spec = 0;
+
+      template <typename ParseContext>
+        constexpr auto parse(ParseContext& ctx) -> decltype (ctx.begin()) {
+          auto it = ctx.begin();
+          if (it != ctx.end() && *it == ':') ++it;
+          if (*it == '>' || *it == '<' || *it == '=') {
+            spec = *it;
+            ++it;
+          }
+          return it;
+        }
+
+      template<class FormatContext>
+        auto format(const pow_format& s, FormatContext &ctx) -> decltype (ctx.out()) {
+          const char* units[] = { "", "k",  "M",  "G",  "T",  "P",  nullptr};
+
+          auto base = s.binary_ ? 1024ull : 1000ll;
+          auto fraction = (double) s.val_;
+
+          int pow;
+          for (pow = 0; units[pow+1] != nullptr && fraction / base >= 1; ++pow) {
+            fraction /= base;
+          }
+
+          const char * format;
+          std::string string;
+          switch (spec) {
+            case '>':
+            case '<':
+              return format_to(ctx.out()
+                  , spec == '<' ? "{:<{}}" : "{:>{}}"
+                  , fmt::format("{}", s)
+                  , 4 /*coeff in :.3g format*/ + 1 /*prefix*/ + s.binary_ + s.unit_.length()
+                  );
+            case '=':
+              format = "{coefficient:<4.3g}{padding}{prefix}{unit}";
+              break;
+            case 0:
+            default:
+              format = "{coefficient:.3g}{prefix}{unit}";
+          }
+          return format_to(ctx.out(), format
+              , fmt::arg("coefficient", fraction)
+              , fmt::arg("prefix", std::string() + units[pow] + ((s.binary_ && pow) ? "i" : ""))
+              , fmt::arg("unit", s.unit_)
+              , fmt::arg("padding", pow ? "" : s.binary_ ? "  " : " ")
+            );
+        }
+    };
 }
+

meson.build

@@ -91,7 +91,6 @@ src_files = files(
     'src/modules/disk.cpp',
     'src/modules/idle_inhibitor.cpp',
     'src/modules/temperature.cpp',
-    'src/util/format.cpp',
     'src/main.cpp',
     'src/bar.cpp',
     'src/client.cpp'

src/modules/disk.cpp

@@ -44,15 +44,33 @@ auto waybar::modules::Disk::update() -> void {
     return;
   }
 
-  label_.set_markup(fmt::format(format_,
-        stats.f_bavail * 100 / stats.f_blocks,
-        fmt::arg("free", pow_format(stats.f_bavail * stats.f_bsize, "B", true)),
-        fmt::arg("percentage_free", stats.f_bavail * 100 / stats.f_blocks),
-        fmt::arg("used", pow_format((stats.f_blocks - stats.f_bavail) * stats.f_bsize, "B", true)),
-        fmt::arg("percentage_used", (stats.f_blocks - stats.f_bavail) * 100 / stats.f_blocks)
-  ));
+  auto free = pow_format(stats.f_bavail * stats.f_bsize, "B", true);
+  auto used = pow_format((stats.f_blocks - stats.f_bavail) * stats.f_bsize, "B", true);
+  auto total = pow_format(stats.f_blocks * stats.f_bsize, "B", true);
+
+  label_.set_markup(fmt::format(format_
+      , stats.f_bavail * 100 / stats.f_blocks
+      , fmt::arg("free", free)
+      , fmt::arg("percentage_free", stats.f_bavail * 100 / stats.f_blocks)
+      , fmt::arg("used", used)
+      , fmt::arg("percentage_used", (stats.f_blocks - stats.f_bavail) * 100 / stats.f_blocks)
+      , fmt::arg("total", total)
+      , fmt::arg("path", path_)
+      ));
   if (tooltipEnabled()) {
-    label_.set_tooltip_text(fmt::format("{} used", pow_format(stats.f_bavail * stats.f_bsize, "B", true)));
+    std::string tooltip_format = "{used} out of {total} used on  ({percentage_used}%)";
+    if (config_["tooltip-format"].isString()) {
+      tooltip_format = config_["tooltip-format"].asString();
+    }
+    label_.set_tooltip_text(fmt::format(tooltip_format
+      , stats.f_bavail * 100 / stats.f_blocks
+      , fmt::arg("free", free)
+      , fmt::arg("percentage_free", stats.f_bavail * 100 / stats.f_blocks)
+      , fmt::arg("used", used)
+      , fmt::arg("percentage_used", (stats.f_blocks - stats.f_bavail) * 100 / stats.f_blocks)
+      , fmt::arg("total", total)
+      , fmt::arg("path", path_)
+      ));
   }
   event_box_.show();
 }