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piyongcai 2024-04-10 16:22:48 +05:00 committed by GitHub
commit 82f2252e92
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2 changed files with 149 additions and 0 deletions

55
decimal_magpack_test.go Normal file
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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)
}
}
}

94
decimal_msgpack.go Normal file
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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
}