bug fix: in the case of constant value on the left side of expression…

… (1+some_column/function), the constant-value was modified per each new-row, which cause a wrong calculation; (#37)

include/s3select_oper.h

@@ -882,7 +882,7 @@ class value
     return compute<binop_mult>(*this, v);
   }
 
-  value& operator/(value& v)  // TODO  handle division by zero
+  value& operator/(value& v)
   {
     if (v.is_null() || this->is_null()) {
       v.set_nan();
@@ -1454,14 +1454,15 @@ class mulldiv_operation : public base_statement
 
 public:
 
-  enum class muldiv_t {NA, MULL, DIV, POW,MOD} ;
+  enum class muldiv_t {NA, MULL, DIV, POW, MOD} ;
 
 private:
   base_statement* l;
   base_statement* r;
 
   muldiv_t _mulldiv;
   value var_value;
+  value tmp_value;
 
 public:
 
@@ -1491,19 +1492,23 @@ class mulldiv_operation : public base_statement
     switch (_mulldiv)
     {
     case muldiv_t::MULL:
-      return var_value = l->eval() * r->eval();
+      tmp_value = l->eval();
+      return var_value = tmp_value * r->eval();
       break;
 
     case muldiv_t::DIV:
-      return var_value = l->eval() / r->eval();
+      tmp_value = l->eval();
+      return var_value = tmp_value / r->eval();
       break;
 
     case muldiv_t::POW:
-      return var_value = l->eval() ^ r->eval();
+      tmp_value = l->eval();
+      return var_value = tmp_value ^ r->eval();
       break;
 
     case muldiv_t::MOD:
-      return var_value = l->eval() % r->eval();
+      tmp_value = l->eval();
+      return var_value = tmp_value % r->eval();
       break;
 
     default:
@@ -1530,6 +1535,7 @@ class addsub_operation : public base_statement
 
   addsub_op_t _op;
   value var_value;
+  value tmp_value;
 
 public:
 
@@ -1571,12 +1577,12 @@ class addsub_operation : public base_statement
       }
     }
     else if (_op == addsub_op_t::ADD)
-    {
-      return var_value = (l->eval() + r->eval());
+    {tmp_value=l->eval();
+      return var_value = (tmp_value + r->eval());
     }
     else
-    {
-      return var_value = (l->eval() - r->eval());
+    {tmp_value=l->eval();
+      return var_value = (tmp_value - r->eval());
     }
 
     return var_value;

test/s3select_test.cpp

@@ -485,6 +485,43 @@ TEST(TestS3selectFunctions, max)
     ASSERT_EQ(s3select_result, std::string("127,12.699999999999999,"));
 }
 
+
+int count_string(std::string in,std::string substr)
+{
+    int count = 0;
+    size_t nPos = in.find(substr, 0); // first occurrence
+    while(nPos != std::string::npos)
+    {
+        count++;
+        nPos = in.find(substr, nPos + 1);
+    }
+
+    return count;
+}
+
+TEST(TestS3selectFunctions, binop_constant)
+{
+    //bug-fix for expresion with constant value on the left side(the bug change the constant values between rows)
+    s3select s3select_syntax;
+    const std::string input_query = "select 10+1,20-12,2*3,128/2,29%5,2^10 from stdin;";
+    auto status = s3select_syntax.parse_query(input_query.c_str());
+    ASSERT_EQ(status, 0);
+    s3selectEngine::csv_object s3_csv_object(&s3select_syntax);
+    std::string s3select_result;
+    std::string input;
+    size_t size = 128;
+    generate_csv(input, size);
+    status = s3_csv_object.run_s3select_on_object(s3select_result, input.c_str(), input.size(), 
+        false, // dont skip first line 
+        false, // dont skip last line
+        true   // aggregate call
+        ); 
+    ASSERT_EQ(status, 0);
+
+    int count = count_string(s3select_result,"11,8,6,64,4,1024");
+    ASSERT_EQ(count,size);
+}
+
 TEST(TestS3selectOperator, add)
 {
     const std::string input_query = "select -5 + 0.5 + -0.25 from stdin;" ;