From 9b5d05d9240766c5db4c6435984020b3fbdc9e8b Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <mo@bunkus.online>
Date: Wed, 21 Sep 2022 15:58:09 +0200
Subject: [PATCH] table formatter: support for column alignments

---
 src/common/strings/table_formatter.cpp | 19 ++++++++++++++++++-
 src/common/strings/table_formatter.h   |  9 +++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/common/strings/table_formatter.cpp b/src/common/strings/table_formatter.cpp
index dbfc393a2..2860fa96c 100644
--- a/src/common/strings/table_formatter.cpp
+++ b/src/common/strings/table_formatter.cpp
@@ -24,6 +24,13 @@ table_formatter_c::set_header(std::vector<std::string> const &header) {
   return *this;
 }
 
+table_formatter_c &
+table_formatter_c::set_alignment(std::vector<alignment_e> const &alignment) {
+  m_alignment = alignment;
+  return *this;
+}
+
+
 table_formatter_c &
 table_formatter_c::add_row(std::vector<std::string> const &row) {
   m_rows.emplace_back(row);
@@ -37,6 +44,10 @@ table_formatter_c::format()
     return {};
 
   auto num_columns = m_header.size();
+  auto alignment   = m_alignment;
+
+  while (alignment.size() < num_columns)
+    alignment.push_back(align_left);
 
   // 1. Calculate column widths.
   std::vector<uint64_t> column_widths(num_columns, 0ull);
@@ -53,10 +64,16 @@ table_formatter_c::format()
   column_formats.reserve(num_columns);
 
   auto row_size = 1u + (num_columns - 1) * 3;
+  auto idx      = 0;
 
   for (auto width : column_widths) {
-    column_formats.emplace_back(fmt::format("{{0:{0:}s}}", width));
+    auto fmt_alignment = alignment[idx] == align_left  ? "<"
+                       : alignment[idx] == align_right ? ">"
+                       :                                 "^";
+
+    column_formats.emplace_back(fmt::format("{{0:{0}{1}s}}", fmt_alignment, width));
     row_size += width;
+    ++idx;
   }
 
   // 3. Reserve space for full output & create row formatting lambda.
diff --git a/src/common/strings/table_formatter.h b/src/common/strings/table_formatter.h
index 889554524..5f6f9dc31 100644
--- a/src/common/strings/table_formatter.h
+++ b/src/common/strings/table_formatter.h
@@ -16,12 +16,21 @@
 namespace mtx::string {
 
 class table_formatter_c {
+public:
+  enum alignment_e {
+    align_left,
+    align_right,
+    align_center,
+  };
+
 private:
   std::vector<std::string> m_header;
+  std::vector<alignment_e> m_alignment;
   std::vector<std::vector<std::string>> m_rows;
 
 public:
   table_formatter_c &set_header(std::vector<std::string> const &header);
+  table_formatter_c &set_alignment(std::vector<alignment_e> const &alignment);
   table_formatter_c &add_row(std::vector<std::string> const &row);
   std::string format() const;
 };