Merge pull request Mooophy#373 from chihyang/master

Simplify header files of exercise 15.39

ch15/ex15.39.40/main.cpp

@@ -29,13 +29,8 @@
 #include <memory>
 #include <fstream>
 
-#include "queryresult.h"
 #include "textquery.h"
-#include "query_base.h"
 #include "query.h"
-#include "andquery.h"
-#include "orquery.h"
-#include "notquery.h"
 
 int main()
 {

ch15/ex15.39.40/query.cpp

@@ -1,3 +1,70 @@
+#include <algorithm>
 #include "query.h"
+/**
+ * @brief AndQuery::eval
+ * @return the intersection of its operands' result sets
+ */
+QueryResult AndQuery::eval(const TextQuery &text) const
+{
+    // virtual calls through the Query operands to get result sets for the operands
+    QueryResult left = lhs.eval(text), right = rhs.eval(text);
 
+    // set to hold the intersection of the left and right
+    std::shared_ptr<std::set<line_no>>
+                   ret_lines = std::make_shared<std::set<line_no>>();
 
+    // writes the intersection of two ranges to a destination iterator
+    std::set_intersection(left.begin(), left.end(),
+                          right.begin(), right.end(),
+                          std::inserter(*ret_lines, ret_lines->begin()));
+
+    return QueryResult(rep(), ret_lines, left.get_file());
+}
+
+/**
+ * @brief OrQuery::eval
+ * @return the union of its operands' result sets
+ */
+QueryResult OrQuery::eval(const TextQuery &text) const
+{
+    QueryResult right = rhs.eval(text), left= lhs.eval(text);
+
+    // copy the left-hand operand into the result set
+    std::shared_ptr<std::set<line_no>> ret_lines =
+            std::make_shared<std::set<line_no>>(left.begin(), left.end());
+
+    // inert lines from the right-hand operand
+    ret_lines->insert(right.begin(), right.end());
+
+    return QueryResult(rep(), ret_lines, left.get_file());
+}
+
+/**
+ * @brief NotQuery::eval
+ * @return the lines not in its operand's result set
+ */
+QueryResult NotQuery::eval(const TextQuery &text) const
+{
+    // virtual call to eval through the Query operand
+    QueryResult result = query.eval(text);
+
+    // start out with an empty result set
+    std::shared_ptr<std::set<line_no>>
+            ret_lines = std::make_shared<std::set<line_no>>();
+
+    std::set<TextQuery::line_no>::iterator
+            begin = result.begin(),
+            end   = result.end();
+
+    StrBlob::size_type sz = result.get_file().size();
+
+    for(std::size_t n = 0; n != sz; ++n)
+    {
+        if(begin == end || *begin != n)
+            ret_lines->insert(n);
+        else if (begin != end)
+            ++begin;
+    }
+
+    return QueryResult(rep(), ret_lines, result.get_file());
+}