[internal] add enumerate() helper

src/base/CMakeLists.txt

@@ -52,6 +52,7 @@ add_library(
         is_utf8.hh
         isc.hh
         itertools.hh
+        itertools.enumerate.hh
         keycodes.hh
         line_range.hh
         lnav.console.hh

src/base/Makefile.am

@@ -48,6 +48,7 @@ noinst_HEADERS = \
     is_utf8.hh \
     isc.hh \
     itertools.hh \
+    itertools.enumerate.hh \
     keycodes.hh \
     line_range.hh \
     lnav_log.hh \

src/base/itertools.enumerate.hh

@@ -0,0 +1,88 @@
+/**
+ * Copyright (c) 2024, Timothy Stack
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * * Neither the name of Timothy Stack nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef lnav_itertools_enumerate_hh
+#define lnav_itertools_enumerate_hh
+
+#include <tuple>
+
+namespace lnav::itertools {
+
+namespace details {
+
+template<typename Iterator, typename CounterType = size_t>
+class EnumerateIterator {
+    Iterator iter;
+    CounterType index;
+
+public:
+    EnumerateIterator(Iterator iter, CounterType index)
+        : iter(std::move(iter)), index(index)
+    {
+    }
+
+    EnumerateIterator& operator++()
+    {
+        ++iter;
+        ++index;
+        return *this;
+    }
+
+    auto operator*() { return std::forward_as_tuple(index, *iter); }
+    bool operator!=(EnumerateIterator const& rhs) const
+    {
+        return iter != rhs.iter;
+    }
+};
+
+}  // namespace details
+
+template<typename Iterable, typename CounterType = size_t>
+class enumerate {
+public:
+    enumerate(Iterable& iterable, CounterType start = 0)
+        : iterable(iterable), index(start)
+    {
+    }
+
+    auto begin()
+    {
+        return details::EnumerateIterator{std::begin(iterable), index};
+    }
+
+    auto end() { return details::EnumerateIterator{std::end(iterable), index}; }
+
+private:
+    Iterable& iterable;
+    CounterType index;
+};
+
+}  // namespace lnav::itertools
+
+#endif

src/breadcrumb_curses.cc

@@ -29,6 +29,7 @@
 
 #include "breadcrumb_curses.hh"
 
+#include "base/itertools.enumerate.hh"
 #include "base/itertools.hh"
 #include "itertools.similar.hh"
 
@@ -39,7 +40,8 @@ breadcrumb_curses::no_op_action(breadcrumb_curses&)
 {
 }
 
-breadcrumb_curses::breadcrumb_curses()
+breadcrumb_curses::
+breadcrumb_curses()
 {
     this->bc_match_search_overlay.sos_parent = this;
     this->bc_match_source.set_reverse_selection(true);
@@ -60,7 +62,6 @@ breadcrumb_curses::do_update()
         return false;
     }
 
-    size_t crumb_index = 0;
     size_t sel_crumb_offset = 0;
     auto width = static_cast<size_t>(getmaxx(this->bc_window));
     auto crumbs = this->bc_focused_crumbs.empty() ? this->bc_line_source()
@@ -72,7 +73,8 @@ breadcrumb_curses::do_update()
     }
     this->bc_displayed_crumbs.clear();
     attr_line_t crumbs_line;
-    for (const auto& crumb : crumbs) {
+    for (const auto& [crumb_index, crumb] : lnav::itertools::enumerate(crumbs))
+    {
         auto accum_width = crumbs_line.column_width();
         auto elem_width = crumb.c_display_value.column_width();
         auto is_selected = this->bc_selected_crumb
@@ -99,7 +101,6 @@ breadcrumb_curses::do_update()
                        (int) (accum_width + elem_width),
                        line_range::unit::codepoint},
             crumb_index);
-        crumb_index += 1;
         crumbs_line.append(" \uff1a"_breadcrumb);
     }
 

src/md2attr_line.cc

@@ -30,6 +30,7 @@
 #include "md2attr_line.hh"
 
 #include "base/attr_line.builder.hh"
+#include "base/itertools.enumerate.hh"
 #include "base/itertools.hh"
 #include "base/lnav_log.hh"
 #include "base/map_util.hh"
@@ -76,10 +77,11 @@ md2attr_line::flush_footnotes()
     auto longest_foot = this->ml_footnotes
         | lnav::itertools::map(&attr_line_t::utf8_length_or_length)
         | lnav::itertools::max(0);
-    size_t index = 1;
 
     block_text.append("\n");
-    for (auto& foot : this->ml_footnotes) {
+    for (const auto& [index, foot] :
+         lnav::itertools::enumerate(this->ml_footnotes, 1))
+    {
         auto footline
             = attr_line_t(" ")
                   .append("\u258c"_footnote_border)
@@ -91,7 +93,6 @@ md2attr_line::flush_footnotes()
                   .with_attr_for_all(SA_PREFORMATTED.value());
 
         block_text.append(footline).append("\n");
-        index += 1;
     }
     this->ml_footnotes.clear();
 }