blob: f318d2c59da39455d627fcc79e1b8af3bd88799e [file] [log] [blame]
Scott Bakere7144bc2019-10-01 14:16:47 -07001package jsoniter
2
3import (
4 "math"
5 "strconv"
6)
7
8var pow10 []uint64
9
10func init() {
11 pow10 = []uint64{1, 10, 100, 1000, 10000, 100000, 1000000}
12}
13
14// WriteFloat32 write float32 to stream
15func (stream *Stream) WriteFloat32(val float32) {
16 abs := math.Abs(float64(val))
17 fmt := byte('f')
18 // Note: Must use float32 comparisons for underlying float32 value to get precise cutoffs right.
19 if abs != 0 {
20 if float32(abs) < 1e-6 || float32(abs) >= 1e21 {
21 fmt = 'e'
22 }
23 }
24 stream.buf = strconv.AppendFloat(stream.buf, float64(val), fmt, -1, 32)
25}
26
27// WriteFloat32Lossy write float32 to stream with ONLY 6 digits precision although much much faster
28func (stream *Stream) WriteFloat32Lossy(val float32) {
29 if val < 0 {
30 stream.writeByte('-')
31 val = -val
32 }
33 if val > 0x4ffffff {
34 stream.WriteFloat32(val)
35 return
36 }
37 precision := 6
38 exp := uint64(1000000) // 6
39 lval := uint64(float64(val)*float64(exp) + 0.5)
40 stream.WriteUint64(lval / exp)
41 fval := lval % exp
42 if fval == 0 {
43 return
44 }
45 stream.writeByte('.')
46 for p := precision - 1; p > 0 && fval < pow10[p]; p-- {
47 stream.writeByte('0')
48 }
49 stream.WriteUint64(fval)
50 for stream.buf[len(stream.buf)-1] == '0' {
51 stream.buf = stream.buf[:len(stream.buf)-1]
52 }
53}
54
55// WriteFloat64 write float64 to stream
56func (stream *Stream) WriteFloat64(val float64) {
57 abs := math.Abs(val)
58 fmt := byte('f')
59 // Note: Must use float32 comparisons for underlying float32 value to get precise cutoffs right.
60 if abs != 0 {
61 if abs < 1e-6 || abs >= 1e21 {
62 fmt = 'e'
63 }
64 }
65 stream.buf = strconv.AppendFloat(stream.buf, float64(val), fmt, -1, 64)
66}
67
68// WriteFloat64Lossy write float64 to stream with ONLY 6 digits precision although much much faster
69func (stream *Stream) WriteFloat64Lossy(val float64) {
70 if val < 0 {
71 stream.writeByte('-')
72 val = -val
73 }
74 if val > 0x4ffffff {
75 stream.WriteFloat64(val)
76 return
77 }
78 precision := 6
79 exp := uint64(1000000) // 6
80 lval := uint64(val*float64(exp) + 0.5)
81 stream.WriteUint64(lval / exp)
82 fval := lval % exp
83 if fval == 0 {
84 return
85 }
86 stream.writeByte('.')
87 for p := precision - 1; p > 0 && fval < pow10[p]; p-- {
88 stream.writeByte('0')
89 }
90 stream.WriteUint64(fval)
91 for stream.buf[len(stream.buf)-1] == '0' {
92 stream.buf = stream.buf[:len(stream.buf)-1]
93 }
94}