blob: 826aa594ac6f34a832fd3a4b8e4dea654278dc3b [file] [log] [blame]
Matteo Scandoloa4285862020-12-01 18:10:10 -08001package jsoniter
2
3import (
4 "fmt"
5 "math"
6 "strconv"
7)
8
9var pow10 []uint64
10
11func init() {
12 pow10 = []uint64{1, 10, 100, 1000, 10000, 100000, 1000000}
13}
14
15// WriteFloat32 write float32 to stream
16func (stream *Stream) WriteFloat32(val float32) {
17 if math.IsInf(float64(val), 0) || math.IsNaN(float64(val)) {
18 stream.Error = fmt.Errorf("unsupported value: %f", val)
19 return
20 }
21 abs := math.Abs(float64(val))
22 fmt := byte('f')
23 // Note: Must use float32 comparisons for underlying float32 value to get precise cutoffs right.
24 if abs != 0 {
25 if float32(abs) < 1e-6 || float32(abs) >= 1e21 {
26 fmt = 'e'
27 }
28 }
29 stream.buf = strconv.AppendFloat(stream.buf, float64(val), fmt, -1, 32)
30}
31
32// WriteFloat32Lossy write float32 to stream with ONLY 6 digits precision although much much faster
33func (stream *Stream) WriteFloat32Lossy(val float32) {
34 if math.IsInf(float64(val), 0) || math.IsNaN(float64(val)) {
35 stream.Error = fmt.Errorf("unsupported value: %f", val)
36 return
37 }
38 if val < 0 {
39 stream.writeByte('-')
40 val = -val
41 }
42 if val > 0x4ffffff {
43 stream.WriteFloat32(val)
44 return
45 }
46 precision := 6
47 exp := uint64(1000000) // 6
48 lval := uint64(float64(val)*float64(exp) + 0.5)
49 stream.WriteUint64(lval / exp)
50 fval := lval % exp
51 if fval == 0 {
52 return
53 }
54 stream.writeByte('.')
55 for p := precision - 1; p > 0 && fval < pow10[p]; p-- {
56 stream.writeByte('0')
57 }
58 stream.WriteUint64(fval)
59 for stream.buf[len(stream.buf)-1] == '0' {
60 stream.buf = stream.buf[:len(stream.buf)-1]
61 }
62}
63
64// WriteFloat64 write float64 to stream
65func (stream *Stream) WriteFloat64(val float64) {
66 if math.IsInf(val, 0) || math.IsNaN(val) {
67 stream.Error = fmt.Errorf("unsupported value: %f", val)
68 return
69 }
70 abs := math.Abs(val)
71 fmt := byte('f')
72 // Note: Must use float32 comparisons for underlying float32 value to get precise cutoffs right.
73 if abs != 0 {
74 if abs < 1e-6 || abs >= 1e21 {
75 fmt = 'e'
76 }
77 }
78 stream.buf = strconv.AppendFloat(stream.buf, float64(val), fmt, -1, 64)
79}
80
81// WriteFloat64Lossy write float64 to stream with ONLY 6 digits precision although much much faster
82func (stream *Stream) WriteFloat64Lossy(val float64) {
83 if math.IsInf(val, 0) || math.IsNaN(val) {
84 stream.Error = fmt.Errorf("unsupported value: %f", val)
85 return
86 }
87 if val < 0 {
88 stream.writeByte('-')
89 val = -val
90 }
91 if val > 0x4ffffff {
92 stream.WriteFloat64(val)
93 return
94 }
95 precision := 6
96 exp := uint64(1000000) // 6
97 lval := uint64(val*float64(exp) + 0.5)
98 stream.WriteUint64(lval / exp)
99 fval := lval % exp
100 if fval == 0 {
101 return
102 }
103 stream.writeByte('.')
104 for p := precision - 1; p > 0 && fval < pow10[p]; p-- {
105 stream.writeByte('0')
106 }
107 stream.WriteUint64(fval)
108 for stream.buf[len(stream.buf)-1] == '0' {
109 stream.buf = stream.buf[:len(stream.buf)-1]
110 }
111}