From c283a2f12395df0d8e40b965b116e8df7e7bb7f3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Wed, 24 Apr 2019 20:59:00 +0200
Subject: [PATCH] Fixes #26 ("Invalid iterator increment/decrement in the last
 iteration of adaptive_sort_combine_blocks")

---
 doc/move.qbk                                      |  7 +++++++
 include/boost/move/algo/adaptive_sort.hpp         | 10 ++++++++--
 include/boost/move/algo/detail/set_difference.hpp |  2 +-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/doc/move.qbk b/doc/move.qbk
index 413fafe..e7a3be0 100644
--- a/doc/move.qbk
+++ b/doc/move.qbk
@@ -802,6 +802,13 @@ Special thanks to:
 
 [section:release_notes Release Notes]
 
+[section:release_notes_boost_1_71 Boost 1.71 Release]
+
+*  Fixed bugs:
+   *  [@https://github.com/boostorg/move/issues/26 Git Issue #26: ['"Invalid iterator increment/decrement in the last iteration of adaptive_sort_combine_blocks"]].
+
+[endsect]
+
 [section:release_notes_boost_1_70 Boost 1.70 Release]
 
 *  Removed support for deprecated GCC compilers.
diff --git a/include/boost/move/algo/adaptive_sort.hpp b/include/boost/move/algo/adaptive_sort.hpp
index 5819399..cdffa2e 100644
--- a/include/boost/move/algo/adaptive_sort.hpp
+++ b/include/boost/move/algo/adaptive_sort.hpp
@@ -180,7 +180,7 @@ void adaptive_sort_combine_blocks
    size_type const max_i = n_reg_combined + (l_irreg_combined != 0);
 
    if(merge_left || !use_buf) {
-      for( size_type combined_i = 0; combined_i != max_i; ++combined_i, combined_first += l_reg_combined) {
+      for( size_type combined_i = 0; combined_i != max_i; ) {
          //Now merge blocks
          bool const is_last = combined_i==n_reg_combined;
          size_type const l_cur_combined = is_last ? l_irreg_combined : l_reg_combined;
@@ -202,11 +202,15 @@ void adaptive_sort_combine_blocks
                (keys, key_comp, combined_first, l_block, 0u, n_block_a, n_block_b, l_irreg2, comp, xbuf_used);
          }
          BOOST_MOVE_ADAPTIVE_SORT_PRINT_L2("   After merge_blocks_L: ", len + l_block);
+         ++combined_i;
+         if(combined_i != max_i)
+            combined_first += l_reg_combined;
       }
    }
    else{
       combined_first += l_reg_combined*(max_i-1);
-      for( size_type combined_i = max_i; combined_i--; combined_first -= l_reg_combined) {
+      for( size_type combined_i = max_i; combined_i; ) {
+         --combined_i;
          bool const is_last = combined_i==n_reg_combined;
          size_type const l_cur_combined = is_last ? l_irreg_combined : l_reg_combined;
 
@@ -222,6 +226,8 @@ void adaptive_sort_combine_blocks
          merge_blocks_right
             (keys, key_comp, combined_first, l_block, n_block_a, n_block_b, l_irreg2, comp, xbuf_used);
          BOOST_MOVE_ADAPTIVE_SORT_PRINT_L2("   After merge_blocks_R: ", len + l_block);
+         if(combined_i)
+            combined_first -= l_reg_combined;
       }
    }
 }
diff --git a/include/boost/move/algo/detail/set_difference.hpp b/include/boost/move/algo/detail/set_difference.hpp
index 51d0475..c988294 100644
--- a/include/boost/move/algo/detail/set_difference.hpp
+++ b/include/boost/move/algo/detail/set_difference.hpp
@@ -174,7 +174,7 @@ ForwardOutputIt1 inplace_set_unique_difference
          ++first2;
       }
       else if (comp(*first1, *first2)){
-         //skip any adjacent equivalent elementin range 1
+         //skip any adjacent equivalent element in range 1
          ForwardOutputIt1 result = first1;
          if (++first1 != last1 && !comp(*result, *first1)) {
             //Some elements from range 1 must be skipped, no longer an inplace operation