Merge pull request #4 from bugless/quick-conversions

Quick conversions
bugless · Jul 16, 2021 · 088ebf6 · 088ebf6
2 parents bee976a + 049a16e
commit 088ebf6
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # CHANGELOG
 
+## 0.2.0
+- Implement and test toDouble, toBigInt and toInt
+
 ## 0.1.0
 - Better parser and toString implementations
 - Fix problems with rounding

diff --git a/lib/src/big_decimal.dart b/lib/src/big_decimal.dart
@@ -149,6 +149,11 @@ class BigDecimal implements Comparable<BigDecimal> {
     throw Exception('Invalid operation: Exponent should be between 0 and 999999999');
   }
 
+  double toDouble() => intVal.toDouble() / BigInt.from(10).pow(scale).toDouble();
+  BigInt toBigInt({RoundingMode roundingMode = RoundingMode.UNNECESSARY}) =>
+      withScale(0, roundingMode: roundingMode).intVal;
+  int toInt({RoundingMode roundingMode = RoundingMode.UNNECESSARY}) => toBigInt(roundingMode: roundingMode).toInt();
+
   BigDecimal withScale(
     int newScale, {
     RoundingMode roundingMode = RoundingMode.UNNECESSARY,

diff --git a/pubspec.yaml b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: big_decimal
-version: 0.1.0
+version: 0.2.0
 description: >
   A bugless implementation of BigDecimal in Dart based on Java's BigDecimal
 

diff --git a/test/big_decimal_test.dart b/test/big_decimal_test.dart
@@ -320,6 +320,72 @@ void main() {
     });
   });
 
+  group(
+    'toDouble',
+    tabular((BigDecimal bd, double d) {
+      expect(bd.toDouble(), d);
+    }, [
+      tabCase(['1.5'.dec, 1.5]),
+      tabCase(['0'.dec, 0.0]),
+      tabCase(['-0'.dec, 0.0]),
+      tabCase([BigInt.from(9223372036854775807).dec, 9223372036854775807.0]),
+      // the above case and the one below are actually the same, because
+      // 9223372036854775807 is not perfectly representable by a double
+      // it gets "rounded" to 9223372036854776000.0
+      tabCase([BigInt.from(9223372036854775807).dec, 9223372036854776000.0]),
+      tabCase([BigInt.from(-9223372036854775808).dec, -9223372036854775808.0]),
+      tabCase([BigInt.from(-9223372036854775808).dec, -9223372036854776000.0]),
+    ]),
+  );
+
+  group(
+    'toBigInt',
+    tabular((BigDecimal bd, BigInt bint, [RoundingMode roundingMode = RoundingMode.UNNECESSARY]) {
+      expect(bd.toBigInt(roundingMode: roundingMode), bint);
+    }, [
+      tabCase(['1.5'.dec, BigInt.from(1), RoundingMode.DOWN]),
+      tabCase(['1.5'.dec, BigInt.from(1), RoundingMode.FLOOR]),
+      tabCase(['1.5'.dec, BigInt.from(2), RoundingMode.UP]),
+      tabCase(['1.5'.dec, BigInt.from(2), RoundingMode.CEILING]),
+      tabCase(['1.5'.dec, BigInt.from(2), RoundingMode.HALF_EVEN]),
+      tabCase(['1.5'.dec, BigInt.from(2), RoundingMode.HALF_UP]),
+      tabCase(['1.5'.dec, BigInt.from(1), RoundingMode.HALF_DOWN]),
+      tabCase(['-1.5'.dec, BigInt.from(-1), RoundingMode.DOWN]),
+      tabCase(['-1.5'.dec, BigInt.from(-2), RoundingMode.FLOOR]),
+      tabCase(['-1.5'.dec, BigInt.from(-2), RoundingMode.UP]),
+      tabCase(['-1.5'.dec, BigInt.from(-1), RoundingMode.CEILING]),
+      tabCase(['-1.5'.dec, BigInt.from(-2), RoundingMode.HALF_EVEN]),
+      tabCase(['-1.5'.dec, BigInt.from(-2), RoundingMode.HALF_UP]),
+      tabCase(['-1.5'.dec, BigInt.from(-1), RoundingMode.HALF_DOWN]),
+      tabCase(['92233720368547758089999'.dec, BigInt.parse('92233720368547758089999')], 'very large integer'),
+      tabCase(['-92233720368547758089999'.dec, BigInt.parse('-92233720368547758089999')], 'very small integer'),
+    ]),
+  );
+
+  group(
+    'toInt',
+    tabular((BigDecimal bd, int i, [RoundingMode roundingMode = RoundingMode.UNNECESSARY]) {
+      expect(bd.toInt(roundingMode: roundingMode), i);
+    }, [
+      tabCase(['1.5'.dec, 1, RoundingMode.DOWN]),
+      tabCase(['1.5'.dec, 1, RoundingMode.FLOOR]),
+      tabCase(['1.5'.dec, 2, RoundingMode.UP]),
+      tabCase(['1.5'.dec, 2, RoundingMode.CEILING]),
+      tabCase(['1.5'.dec, 2, RoundingMode.HALF_EVEN]),
+      tabCase(['1.5'.dec, 2, RoundingMode.HALF_UP]),
+      tabCase(['1.5'.dec, 1, RoundingMode.HALF_DOWN]),
+      tabCase(['-1.5'.dec, -1, RoundingMode.DOWN]),
+      tabCase(['-1.5'.dec, -2, RoundingMode.FLOOR]),
+      tabCase(['-1.5'.dec, -2, RoundingMode.UP]),
+      tabCase(['-1.5'.dec, -1, RoundingMode.CEILING]),
+      tabCase(['-1.5'.dec, -2, RoundingMode.HALF_EVEN]),
+      tabCase(['-1.5'.dec, -2, RoundingMode.HALF_UP]),
+      tabCase(['-1.5'.dec, -1, RoundingMode.HALF_DOWN]),
+      tabCase(['92233720368547758089999'.dec, 9223372036854775807], 'very large integer'),
+      tabCase(['-92233720368547758089999'.dec, -9223372036854775808], 'very small integer'),
+    ]),
+  );
+
   group(
     'toString()',
     tabular((Object a, String result) {