Fixed bug in a timsort algorithm.

coding/coding_tests/coding_tests.pro

@@ -12,46 +12,47 @@ include($$ROOT_DIR/common.pri)
 win32-g++: LIBS *= -lpthread
 
 SOURCES += ../../testing/testingmain.cpp \
-    endianness_test.cpp \
-    varint_test.cpp \
-    mem_file_reader_test.cpp \
-    mem_file_writer_test.cpp \
-    var_serial_vector_test.cpp \
-    hex_test.cpp \
-    dd_vector_test.cpp \
-    diff_test.cpp \
-    png_decoder_test.cpp \
-    reader_test.cpp \
-    writer_test.cpp \
-    var_record_reader_test.cpp \
-    file_sort_test.cpp \
-    reader_cache_test.cpp \
-    file_container_test.cpp \
-    url_encode_test.cpp \
-    bzip2_test.cpp \
-    gzip_test.cpp \
-    coder_util_test.cpp \
-    bit_shift_test.cpp \
-    base64_test.cpp \
-    base64_for_user_id_test.cpp \
-    sha2_test.cpp \
-    value_opt_string_test.cpp \
-    multilang_utf8_string_test.cpp \
-    file_data_test.cpp \
-    zip_reader_test.cpp \
-    trie_test.cpp \
-    reader_writer_ops_test.cpp \
-    blob_storage_test.cpp \
-    uri_test.cpp \
-    zip_creator_test.cpp \
-    file_utils_test.cpp \
-    varint_vector_test.cpp \
     arithmetic_codec_test.cpp \
+    base64_for_user_id_test.cpp \
+    base64_test.cpp \
+    bit_shift_test.cpp \
+    bit_streams_test.cpp \
+    blob_storage_test.cpp \
+    bzip2_test.cpp \
+    coder_util_test.cpp \
     compressed_bit_vector_test.cpp \
     compressed_varnum_vector_test.cpp \
-    bit_streams_test.cpp \
+    dd_vector_test.cpp \
+    diff_test.cpp \
+    endianness_test.cpp \
+    file_container_test.cpp \
+    file_data_test.cpp \
+    file_sort_test.cpp \
+    file_utils_test.cpp \
+    gzip_test.cpp \
+    hex_test.cpp \
+    mem_file_reader_test.cpp \
+    mem_file_writer_test.cpp \
+    multilang_utf8_string_test.cpp \
+    png_decoder_test.cpp \
+    reader_cache_test.cpp \
+    reader_test.cpp \
+    reader_writer_ops_test.cpp \
+    sha2_test.cpp \
+    timsort_test.cpp \
+    trie_test.cpp \
+    uri_test.cpp \
+    url_encode_test.cpp \
+    value_opt_string_test.cpp \
+    var_record_reader_test.cpp \
+    var_serial_vector_test.cpp \
+    varint_test.cpp \
+    varint_vector_test.cpp \
+    writer_test.cpp \
+    zip_creator_test.cpp \
+    zip_reader_test.cpp \
 
 HEADERS += \
-    reader_test.hpp \
     coder_test.hpp \
     compressor_test_utils.hpp \
+    reader_test.hpp \

coding/coding_tests/timsort_test.cpp

@@ -0,0 +1,33 @@
+#include "../../testing/testing.hpp"
+
+#include "../timsort/timsort.hpp"
+
+#include "../../std/algorithm.hpp"
+#include "../../std/vector.hpp"
+
+int intCmp(void const * plhs, void const * prhs)
+{
+  int const lhs = *static_cast<int const *>(plhs);
+  int const rhs = *static_cast<int const *>(prhs);
+  if (lhs < rhs)
+    return -1;
+  if (lhs == rhs)
+    return 0;
+  return 1;
+}
+
+UNIT_TEST(TimSort_Empty) {
+  vector<int> buffer;
+  timsort(&buffer[0], 0, sizeof(int), intCmp);
+}
+
+UNIT_TEST(Timsort_Simple) {
+  vector<int> buffer = { 5, 1, 0, 7, 9, 10, 1, 3, 4 };
+
+  vector<int> sorted_buffer(buffer);
+  sort(sorted_buffer.begin(), sorted_buffer.end());
+
+  timsort(&buffer[0], buffer.size(), sizeof(int), intCmp);
+
+  TEST_EQUAL(sorted_buffer, buffer, ());
+}

coding/timsort/timsort.cpp

@@ -1183,7 +1183,8 @@ static void timMergeCollapse(timMergeState *aState, cmpFunc *aCmpCb)
     {
         n = aState->mPendingRunCnt - 2;
 
-        if (n > 0 && sSlice[n-1].mLen <= sSlice[n].mLen + sSlice[n+1].mLen)
+        if ((n > 0 && sSlice[n-1].mLen <= sSlice[n].mLen + sSlice[n+1].mLen) ||
+            (n-1 > 0 && sSlice[n-2].mLen <= sSlice[n].mLen + sSlice[n-1].mLen))
         {
             if (sSlice[n-1].mLen < sSlice[n+1].mLen)
             {