followup: do not use uniform_real_distribution as it's platform depen…

…dant
qgis · Dec 13, 2019 · 65112f8 · 65112f8
1 parent adf40e2
commit 65112f8
Show file tree

Hide file tree

Showing 2 changed files with 13 additions and 20 deletions.
diff --git a/src/core/expression/qgsexpressionfunction.cpp b/src/core/expression/qgsexpressionfunction.cpp
@@ -376,7 +376,6 @@ static QVariant fcnRndF( const QVariantList &values, const QgsExpressionContext
 
   std::random_device rd;
   std::mt19937_64 generator( rd() );
-  std::uniform_real_distribution<double> dist( min, max );
 
   if ( !QgsExpressionUtils::isNull( values.at( 2 ) ) )
   {
@@ -397,7 +396,8 @@ static QVariant fcnRndF( const QVariantList &values, const QgsExpressionContext
   }
 
   // Return a random integer in the range [min, max] (inclusive)
-  return QVariant( dist( generator ) );
+  double f = static_cast< double >( generator() ) / generator.max();
+  return QVariant( min + f * ( max - min ) );
 }
 static QVariant fcnRnd( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
 {
@@ -408,7 +408,6 @@ static QVariant fcnRnd( const QVariantList &values, const QgsExpressionContext *
 
   std::random_device rd;
   std::mt19937_64 generator( rd() );
-  std::uniform_int_distribution<qlonglong> dist( min, max );
 
   if ( !QgsExpressionUtils::isNull( values.at( 2 ) ) )
   {
@@ -429,7 +428,7 @@ static QVariant fcnRnd( const QVariantList &values, const QgsExpressionContext *
   }
 
   // Return a random integer in the range [min, max] (inclusive)
-  return QVariant( dist( generator ) );
+  return QVariant( min + ( generator() % ( max - min + 1 ) ) );
 }
 
 static QVariant fcnLinearScale( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )

diff --git a/tests/src/core/testqgsexpression.cpp b/tests/src/core/testqgsexpression.cpp
@@ -2179,20 +2179,17 @@ class TestQgsExpression: public QObject
       QCOMPARE( v7.toInt() <= 10, true );
       QCOMPARE( v7.toInt() >= 1, true );
 
-      // Two calls with the same seed return the same number
+      // Two calls with the same seed always return the same number
       QgsExpression exp8( QStringLiteral( "rand(1,1000000000,1)" ) );
       QVariant v8 = exp8.evaluate();
       QCOMPARE( v8.toInt() == 546311529, true );
-      QgsExpression exp9( QStringLiteral( "rand(1,1000000000,1)" ) );
-      QVariant v9 = exp9.evaluate();
-      QCOMPARE( v9.toInt() == 546311529, true );
 
       // Two calls with a different seed return a different number
-      QgsExpression exp10( QStringLiteral( "rand(1,100000000000,1)" ) );
+      QgsExpression exp9( QStringLiteral( "rand(1,100000000000,1)" ) );
+      QVariant v9 = exp9.evaluate();
+      QgsExpression exp10( QStringLiteral( "rand(1,100000000000,2)" ) );
       QVariant v10 = exp10.evaluate();
-      QgsExpression exp11( QStringLiteral( "rand(1,100000000000,2)" ) );
-      QVariant v11 = exp11.evaluate();
-      QCOMPARE( v10.toInt() != v11.toInt(), true );
+      QCOMPARE( v9.toInt() != v10.toInt(), true );
     }
 
     void eval_randf()
@@ -2229,20 +2226,17 @@ class TestQgsExpression: public QObject
       QCOMPARE( v7.toDouble() <= 9.5, true );
       QCOMPARE( v7.toDouble() >= 1.5, true );
 
-      // Two calls with the same seed return the same number
+      // Two calls with the same seed always return the same number
       QgsExpression exp8( QStringLiteral( "randf(seed:=1)" ) );
       QVariant v8 = exp8.evaluate();
       QCOMPARE( v8.toFloat() == 0.13387664401253274, true );
-      QgsExpression exp9( QStringLiteral( "randf(seed:=1)" ) );
-      QVariant v9 = exp9.evaluate();
-      QCOMPARE( v9.toFloat() == 0.13387664401253274, true );
 
       // Two calls with a different seed return a different number
-      QgsExpression exp10( QStringLiteral( "randf(seed:=1)" ) );
+      QgsExpression exp9( QStringLiteral( "randf(seed:=1)" ) );
+      QVariant v9 = exp9.evaluate();
+      QgsExpression exp10( QStringLiteral( "randf(seed:=2)" ) );
       QVariant v10 = exp10.evaluate();
-      QgsExpression exp11( QStringLiteral( "randf(seed:=2)" ) );
-      QVariant v11 = exp11.evaluate();
-      QCOMPARE( v10.toFloat() != v11.toFloat(), true );
+      QCOMPARE( v9.toFloat() != v10.toFloat(), true );
     }
 
     void referenced_columns()