Merge 6e8c4f56de into a1bdfc355e

Mote: Marshal max digits is 30. it decimal.IntPart large than 30,it will be lose extra digits.

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

@@ -1847,6 +1847,11 @@ 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_magpack_test.go

@@ -0,0 +1,55 @@
+package decimal
+
+import (
+	"testing"
+)
+
+func TestMsgPack(t *testing.T) {
+	for _, x := range testTable {
+		s := x.short
+		// limit to 31 digits
+		if len(s) > 31 {
+			s = s[:31]
+			if s[30] == '.' {
+				s = s[:30]
+			}
+		}
+
+		// Prepare Test Decimal Data
+		amount, err := NewFromString(s)
+		if err != nil {
+			t.Error(err)
+		}
+		s = amount.String()
+
+		// MarshalMsg
+		var b []byte
+		out, err := amount.MarshalMsg(b)
+		if err != nil {
+			t.Errorf("error marshalMsg %s: %v", s, err)
+		}
+
+		// check msg type
+		typ := out[0] & 0xe0
+		if typ != 0xa0 {
+			t.Errorf("error marshalMsg, expected type = %b, got %b", 0xa0, typ)
+		}
+
+		// check msg len
+		sz := int(out[0] & 0x1f)
+		if sz != len(s) {
+			t.Errorf("error marshalMsg, expected size = %d, got %d", len(s), sz)
+		}
+
+		// UnmarshalMsg
+		var unmarshalAmount Decimal
+		_, err = unmarshalAmount.UnmarshalMsg(out)
+		if err != nil {
+			t.Errorf("error unmarshalMsg %s: %v", s, err)
+		} else if !unmarshalAmount.Equal(amount) {
+			t.Errorf("expected %s, got %s (%s, %d)",
+				amount.String(), unmarshalAmount.String(),
+				unmarshalAmount.value.String(), unmarshalAmount.exp)
+		}
+	}
+}

decimal_msgpack.go

@@ -0,0 +1,94 @@
+package decimal
+
+import (
+	"errors"
+)
+
+var (
+	errShortBytes = errors.New("msgp: too few bytes left to read object")
+)
+
+// MarshalMsg implements msgp.Marshaler
+//  Note: limit to 31 digits, if d.IntPart size large than 31, will be lose.
+func (d Decimal) MarshalMsg(b []byte) ([]byte, error) {
+	o := require(b, d.Msgsize())
+	str := d.String()
+	sz := len(str)
+	// limit to 31 digits
+	// note, if d.IntPart size large than 3, will be lose.
+	if sz > 31 {
+		sz = 31
+		// if last char is '.' then limit to 30 digits
+		if str[30] == '.' {
+			sz = 30
+		}
+
+		str = str[:sz]
+	}
+
+	o, n := ensure(o, 1+sz)
+	o[n] = byte(0xa0 | sz)
+	n++
+
+	return o[:n+copy(o[n:], str)], nil
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (d *Decimal) UnmarshalMsg(b []byte) ([]byte, error) {
+	o, err := b, errShortBytes
+
+	l := len(b)
+	if l < 1 {
+		return o, err
+	}
+
+	sz := int(b[0] & 0x1f)
+	if len(b[1:]) < sz {
+		return o, err
+	}
+	if *d, err = NewFromString(string(b[1 : sz+1])); err == nil {
+		o = b[sz:]
+	}
+	return o, err
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (d Decimal) Msgsize() int {
+	return 32
+}
+
+// Require ensures that cap(old)-len(old) >= extra.
+func require(old []byte, extra int) []byte {
+	l := len(old)
+	c := cap(old)
+	r := l + extra
+	if c >= r {
+		return old
+	} else if l == 0 {
+		return make([]byte, 0, extra)
+	}
+	// the new size is the greater
+	// of double the old capacity
+	// and the sum of the old length
+	// and the number of new bytes
+	// necessary.
+	c <<= 1
+	if c < r {
+		c = r
+	}
+	n := make([]byte, l, c)
+	copy(n, old)
+	return n
+}
+
+// ensure 'sz' extra bytes in 'b' btw len(b) and cap(b)
+func ensure(b []byte, sz int) ([]byte, int) {
+	l := len(b)
+	c := cap(b)
+	if c-l < sz {
+		o := make([]byte, (2*c)+sz) // exponential growth
+		n := copy(o, b)
+		return o[:n+sz], n
+	}
+	return b[:l+sz], l
+}

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")