feat: add termutil module with bar graph rendering support

cmake/libdwarfs.cmake

@@ -42,6 +42,7 @@ add_library(
   src/pcm_sample_transformer.cpp
   $<IF:$<BOOL:${ENABLE_PERFMON}>,src/performance_monitor.cpp,>
   src/terminal_ansi.cpp
+  src/termutil.cpp
   src/thread_pool.cpp
   src/util.cpp
   src/varint.cpp

include/dwarfs/termutil.h

@@ -0,0 +1,46 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/**
+ * \author     Marcus Holland-Moritz (github@mhxnet.de)
+ * \copyright  Copyright (c) Marcus Holland-Moritz
+ *
+ * This file is part of dwarfs.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the “Software”), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <span>
+#include <string>
+
+namespace dwarfs {
+
+class terminal;
+
+struct bar_chart_section {
+  std::string label;
+  double fraction;
+};
+
+std::string
+render_bar_chart(terminal const& term, std::span<bar_chart_section const> bars);
+
+} // namespace dwarfs

src/termutil.cpp

@@ -0,0 +1,133 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/**
+ * \author     Marcus Holland-Moritz (github@mhxnet.de)
+ * \copyright  Copyright (c) Marcus Holland-Moritz
+ *
+ * This file is part of dwarfs.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the “Software”), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <numeric>
+#include <vector>
+
+#include <dwarfs/terminal.h>
+#include <dwarfs/termutil.h>
+
+namespace dwarfs {
+
+namespace {
+
+struct bar_color {
+  termcolor fg;
+  termcolor bg;
+};
+
+constexpr std::array bar_colors = {
+    bar_color{termcolor::WHITE, termcolor::DIM_BLUE},
+    bar_color{termcolor::BLACK, termcolor::YELLOW},
+    bar_color{termcolor::WHITE, termcolor::RED},
+    bar_color{termcolor::BLACK, termcolor::CYAN},
+    bar_color{termcolor::WHITE, termcolor::MAGENTA},
+    bar_color{termcolor::BLACK, termcolor::GREEN},
+};
+
+} // namespace
+
+std::string render_bar_chart(terminal const& term,
+                             std::span<bar_chart_section const> bars) {
+  auto const width = term.width();
+
+  if (bars.empty() || width == 0) {
+    return {};
+  }
+
+  // ----- 1. how many character cells for each bar? -----
+  double const total_fraction = std::accumulate(
+      bars.begin(), bars.end(), 0.0,
+      [](double s, bar_chart_section const& b) { return s + b.fraction; });
+
+  struct chunk {
+    size_t len = 0;       // integer width actually used
+    double remainder = 0; // fractional remainder (for redistribution)
+  };
+  std::vector<chunk> chunks(bars.size());
+
+  size_t used = 0;
+  for (size_t i = 0; i < bars.size(); ++i) {
+    double const raw =
+        (total_fraction == 0.0
+             ? 0.0
+             : bars[i].fraction / total_fraction * static_cast<double>(width));
+    chunks[i].len = static_cast<size_t>(std::floor(raw));
+    chunks[i].remainder = raw - static_cast<double>(chunks[i].len);
+    used += chunks[i].len;
+  }
+
+  // distribute the remaining columns to the bars with the largest remainders
+  size_t missing = width - used;
+  while (missing > 0) {
+    auto const it =
+        std::max_element(chunks.begin(), chunks.end(), [](auto& a, auto& b) {
+          return a.remainder < b.remainder;
+        });
+    ++it->len;
+    it->remainder = 0.0; // so it doesn’t get another extra column
+    --missing;
+  }
+
+  // ----- 2. build the coloured string bar by bar -----
+  std::string result;
+  result.reserve(width * 16); // rough guess, avoids many reallocations
+
+  for (size_t i = 0; i < bars.size(); ++i) {
+    auto const w = chunks[i].len;
+    if (w == 0) {
+      continue;
+    } // fractions can be tiny – simply skip
+
+    auto const& lbl = bars[i].label;
+    auto const& color = bar_colors[i % bar_colors.size()];
+
+    std::string segment(w, ' '); // filled with spaces → solid background
+
+    if (lbl.size() >= w) { // truncate
+      segment.assign(lbl.substr(0, w));
+    } else { // centre
+      std::size_t const left = (w - lbl.size()) / 2;
+      segment.replace(left, lbl.size(), lbl);
+    }
+
+    result += term.bgcolor(color.bg);
+    result += term.color(color.fg);
+    result += segment;
+  }
+
+  result += term.bgcolor(termcolor::NORMAL);
+  result += term.color(termcolor::NORMAL);
+
+  return result;
+}
+
+} // namespace dwarfs