fix exception "sizes don’t match"

include/xlnt/cell/rich_text.hpp

@@ -151,6 +151,8 @@ class XLNT_API rich_text
     /// </summary>
     bool operator!=(const std::string &rhs) const;
 
+    std::size_t unique_index{0};
+
 private:
     /// <summary>
     /// The runs that make up this rich text.
@@ -171,6 +173,7 @@ class XLNT_API rich_text_hash
         {
             res ^= std::hash<std::string>()(r.first);
         }
+        res ^= std::hash<std::string>()(std::to_string(k.unique_index));
 
         return res;
     }

source/cell/rich_text.cpp

@@ -56,6 +56,7 @@ rich_text &rich_text::operator=(const rich_text &rhs)
     runs_ = rhs.runs_;
     phonetic_runs_ = rhs.phonetic_runs_;
     phonetic_properties_ = rhs.phonetic_properties_;
+    unique_index = rhs.unique_index;
     return *this;
 }
 
@@ -69,6 +70,7 @@ void rich_text::clear()
     runs_.clear();
     phonetic_runs_.clear();
     phonetic_properties_.clear();
+    unique_index = 0;
 }
 
 void rich_text::plain_text(const std::string &s, bool preserve_space = false)
@@ -151,7 +153,7 @@ bool rich_text::operator==(const rich_text &rhs) const
 
     if (phonetic_properties_ != rhs.phonetic_properties_) return false;
 
-    return true;
+    return unique_index == rhs.unique_index;
 }
 
 bool rich_text::operator==(const std::string &rhs) const

source/detail/serialization/xlsx_consumer.cpp

@@ -2270,10 +2270,12 @@ void xlsx_consumer::read_shared_string_table()
         unique_count = parser().attribute<std::size_t>("uniqueCount");
     }
 
+    size_t unique_index = 0;
     while (in_element(qn("spreadsheetml", "sst")))
     {
         expect_start_element(qn("spreadsheetml", "si"), xml::content::complex);
         auto rt = read_rich_text(qn("spreadsheetml", "si"));
+        rt.unique_index = unique_index++;
         target_.add_shared_string(rt, true);
         expect_end_element(qn("spreadsheetml", "si"));
     }