Merge 6e54f647f0 into a1bdfc355e

CHANGELOG.md

@@ -1,3 +1,30 @@
+## Decimal v1.4.0
+#### BREAKING
+- Drop support for Go version older than 1.10 [#361](https://github.com/shopspring/decimal/pull/361)
+
+#### FEATURES
+- Add implementation of natural logarithm [#339](https://github.com/shopspring/decimal/pull/339) [#357](https://github.com/shopspring/decimal/pull/357)
+- Add improved implementation of power operation [#358](https://github.com/shopspring/decimal/pull/358)
+- Add Compare method which forwards calls to Cmp [#346](https://github.com/shopspring/decimal/pull/346)
+- Add NewFromBigRat constructor [#288](https://github.com/shopspring/decimal/pull/288)
+- Add NewFromUint64 constructor [#352](https://github.com/shopspring/decimal/pull/352)
+
+#### ENHANCEMENTS
+- Migrate to Github Actions [#245](https://github.com/shopspring/decimal/pull/245) [#340](https://github.com/shopspring/decimal/pull/340)
+- Fix examples for RoundDown, RoundFloor, RoundUp, and RoundCeil [#285](https://github.com/shopspring/decimal/pull/285) [#328](https://github.com/shopspring/decimal/pull/328) [#341](https://github.com/shopspring/decimal/pull/341)
+- Use Godoc standard to mark deprecated Equals and StringScaled methods [#342](https://github.com/shopspring/decimal/pull/342)
+- Removed unnecessary min function for RescalePair method [#265](https://github.com/shopspring/decimal/pull/265)
+- Avoid reallocation of initial slice in MarshalBinary (GobEncode) [#355](https://github.com/shopspring/decimal/pull/355)
+- Optimize NumDigits method [#301](https://github.com/shopspring/decimal/pull/301) [#356](https://github.com/shopspring/decimal/pull/356)
+- Optimize BigInt method [#359](https://github.com/shopspring/decimal/pull/359)
+- Support scanning uint64 [#131](https://github.com/shopspring/decimal/pull/131) [#364](https://github.com/shopspring/decimal/pull/364)
+- Add docs section with alternative libraries [#363](https://github.com/shopspring/decimal/pull/363)
+
+#### BUGFIXES
+- Fix incorrect calculation of decimal modulo [#258](https://github.com/shopspring/decimal/pull/258) [#317](https://github.com/shopspring/decimal/pull/317)
+- Allocate new(big.Int) in Copy method to deeply clone it [#278](https://github.com/shopspring/decimal/pull/278)
+- Fix overflow edge case in QuoRem method [#322](https://github.com/shopspring/decimal/pull/322)
+
 ## Decimal v1.3.1
 
 #### ENHANCEMENTS

README.md

@@ -24,6 +24,11 @@ Run `go get github.com/shopspring/decimal`
 
 Decimal library requires Go version `>=1.10`
 
+## Documentation
+
+http://godoc.org/github.com/shopspring/decimal
+
+
 ## Usage
 
 ```go
@@ -59,9 +64,16 @@ func main() {
 }
 ```
 
-## Documentation
+## Alternative libraries
 
-http://godoc.org/github.com/shopspring/decimal
+When working with decimal numbers, you might face problems this library is not perfectly suited for. 
+Fortunately, thanks to the wonderful community we have a dozen other libraries that you can choose from.  
+Explore other alternatives to find the one that best fits your needs :)  
+
+* [cockroachdb/apd](https://github.com/cockroachdb/apd) - arbitrary precision, mutable and rich API similar to `big.Int`, more performant than this library 
+* [alpacahq/alpacadecimal](https://github.com/alpacahq/alpacadecimal) - high performance, low precision (12 digits), fully compatible API with this library 
+* [govalues/decimal](https://github.com/govalues/decimal) - high performance, zero-allocation, low precision (19 digits)
+* [greatcloak/decimal](https://github.com/greatcloak/decimal) - fork focusing on billing and e-commerce web application related use cases, includes out-of-the-box BSON marshaling support
 
 ## FAQ
 

decimal.go

@@ -65,6 +65,14 @@ var PowPrecisionNegativeExponent = 16
 // silently lose precision.
 var MarshalJSONWithoutQuotes = false
 
+// StringTrimTrailingZeros should be set to false if you want the decimal stringify without zeros trailing.
+// By default, when decimal is output as a string (for example, in JSON), zeros are truncated from it (2.00 -> 2, 3.11 -> 3.11, 13.000 -> 13).
+// But this logic can be changed by this variable.
+// For example, if you have numeric(10,2) values stored in your database,
+// and you want your API response to always be given 2 decimal places (even 2.00, 3.00, 17.00 [not 2,3,17]),
+// then this variable is a great way out.
+var StringTrimTrailingZeros = true
+
 // ExpMaxIterations specifies the maximum number of iterations needed to calculate
 // precise natural exponent value using ExpHullAbrham method.
 var ExpMaxIterations = 1000
@@ -1469,7 +1477,7 @@ func (d Decimal) InexactFloat64() float64 {
 //
 //	-12.345
 func (d Decimal) String() string {
-	return d.string(true)
+	return d.string(StringTrimTrailingZeros)
 }
 
 // StringFixed returns a rounded fixed-point string with places digits after
@@ -1847,6 +1855,11 @@ func (d *Decimal) Scan(value interface{}) error {
 		*d = New(v, 0)
 		return nil
 
+	case uint64:
+		// while clickhouse may send 0 in db as uint64
+		*d = NewFromUint64(v)
+		return nil
+
 	default:
 		// default is trying to interpret value stored as string
 		str, err := unquoteIfQuoted(v)

decimal_test.go

@@ -2416,104 +2416,57 @@ func TestDecimal_Max(t *testing.T) {
 	}
 }
 
-func TestDecimal_Scan(t *testing.T) {
-	// test the Scan method that implements the
-	// sql.Scanner interface
-	// check for the for different type of values
-	// that are possible to be received from the database
-	// drivers
+func scanHelper(t *testing.T, dbval interface{}, expected Decimal) {
+	t.Helper()
 
-	// in normal operations the db driver (sqlite at least)
-	// will return an int64 if you specified a numeric format
 	a := Decimal{}
-	dbvalue := 54.33
-	expected := NewFromFloat(dbvalue)
-
-	err := a.Scan(dbvalue)
-	if err != nil {
+	if err := a.Scan(dbval); err != nil {
 		// Scan failed... no need to test result value
-		t.Errorf("a.Scan(54.33) failed with message: %s", err)
-
-	} else {
+		t.Errorf("a.Scan(%v) failed with message: %s", dbval, err)
+	} else if !a.Equal(expected) {
 		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
 		t.Errorf("%s does not equal to %s", a, expected)
 	}
 }
 
+func TestDecimal_Scan(t *testing.T) {
+	// test the Scan method that implements the sql.Scanner interface
+	// check different types received from various database drivers
+
+	dbvalue := 54.33
+	expected := NewFromFloat(dbvalue)
+	scanHelper(t, dbvalue, expected)
+
 	// apparently MySQL 5.7.16 and returns these as float32 so we need
 	// to handle these as well
 	dbvalueFloat32 := float32(54.33)
 	expected = NewFromFloat(float64(dbvalueFloat32))
-
-	err = a.Scan(dbvalueFloat32)
-	if err != nil {
-		// Scan failed... no need to test result value
-		t.Errorf("a.Scan(54.33) failed with message: %s", err)
-
-	} else {
-		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
-	}
+	scanHelper(t, dbvalueFloat32, expected)
 
 	// at least SQLite returns an int64 when 0 is stored in the db
 	// and you specified a numeric format on the schema
 	dbvalueInt := int64(0)
 	expected = New(dbvalueInt, 0)
+	scanHelper(t, dbvalueInt, expected)
 
-	err = a.Scan(dbvalueInt)
-	if err != nil {
-		// Scan failed... no need to test result value
-		t.Errorf("a.Scan(0) failed with message: %s", err)
-
-	} else {
-		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
-	}
+	// also test uint64
+	dbvalueUint64 := uint64(2)
+	expected = New(2, 0)
+	scanHelper(t, dbvalueUint64, expected)
 
 	// in case you specified a varchar in your SQL schema,
-	// the database driver will return byte slice []byte
+	// the database driver may return either []byte or string
 	valueStr := "535.666"
 	dbvalueStr := []byte(valueStr)
-	expected, err = NewFromString(valueStr)
+	expected, err := NewFromString(valueStr)
 	if err != nil {
 		t.Fatal(err)
 	}
-
-	err = a.Scan(dbvalueStr)
-	if err != nil {
-		// Scan failed... no need to test result value
-		t.Errorf("a.Scan('535.666') failed with message: %s", err)
-
-	} else {
-		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
-	}
-
-	// lib/pq can also return strings
-	expected, err = NewFromString(valueStr)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	err = a.Scan(valueStr)
-	if err != nil {
-		// Scan failed... no need to test result value
-		t.Errorf("a.Scan('535.666') failed with message: %s", err)
-	} else {
-		// Scan succeeded... test resulting values
-		if !a.Equal(expected) {
-			t.Errorf("%s does not equal to %s", a, expected)
-		}
-	}
+	scanHelper(t, dbvalueStr, expected)
+	scanHelper(t, valueStr, expected)
 
 	type foo struct{}
+	a := Decimal{}
 	err = a.Scan(foo{})
 	if err == nil {
 		t.Errorf("a.Scan(Foo{}) should have thrown an error but did not")
@@ -3694,3 +3647,48 @@ func ExampleNewFromFloat() {
 	//0.123123123123123
 	//-10000000000000
 }
+
+func TestDecimal_String(t *testing.T) {
+	type testData struct {
+		input string
+		expected string
+	}
+
+	tests := []testData{
+		{"1.22", "1.22"},
+		{"1.00", "1"},
+		{"153.192", "153.192"},
+		{"999.999", "999.999"},
+		{"0.0000000001", "0.0000000001"},
+		{"0.0000000000", "0"},
+	}
+
+	for _, test := range tests {
+		d, err := NewFromString(test.input);
+		if err != nil {
+			t.Fatal(err)
+		} else if d.String() != test.expected {
+			t.Errorf("expected %s, got %s", test.expected, d.String())
+		}
+	}
+
+	defer func() {
+		StringTrimTrailingZeros = true
+	}()
+
+	StringTrimTrailingZeros = false
+	tests = []testData{
+		{"1.00", "1.00"},
+		{"0.00", "0.00"},
+		{"129.123000", "129.123000"},
+	}
+
+	for _, test := range tests {
+		d, err := NewFromString(test.input);
+		if err != nil {
+			t.Fatal(err)
+		} else if d.String() != test.expected {
+			t.Errorf("expected %s, got %s", test.expected, d.String())
+		}
+	}
+}