zlog/internal/json/string.go

122 lines
3.3 KiB
Go
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package json
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import "unicode/utf8"
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const hex = "0123456789abcdef"
var noEscapeTable = [256]bool{}
func init() {
for i := 0; i <= 0x7e; i++ {
noEscapeTable[i] = i >= 0x20 && i != '\\' && i != '"'
}
}
// AppendStrings encodes the input strings to json and
// appends the encoded string list to the input byte slice.
Get back some ns by removing the extra inferance added by binary support benchstat old new name old time/op new time/op delta LogEmpty-8 15.2ns ±14% 13.4ns ± 3% -12.11% (p=0.008 n=5+5) Disabled-8 2.50ns ± 1% 2.28ns ± 6% -8.81% (p=0.008 n=5+5) Info-8 44.4ns ± 1% 36.4ns ± 4% -17.99% (p=0.008 n=5+5) ContextFields-8 47.6ns ± 1% 39.4ns ± 7% -17.30% (p=0.008 n=5+5) ContextAppend-8 18.9ns ± 4% 15.2ns ± 4% -19.68% (p=0.008 n=5+5) LogFields-8 181ns ± 2% 173ns ± 2% -4.63% (p=0.008 n=5+5) LogArrayObject-8 530ns ± 3% 487ns ± 3% -8.11% (p=0.008 n=5+5) LogFieldType/Int-8 29.5ns ± 3% 28.8ns ± 2% ~ (p=0.167 n=5+5) LogFieldType/Interface-8 180ns ± 7% 175ns ± 4% ~ (p=0.579 n=5+5) LogFieldType/Interface(Object)-8 87.8ns ± 3% 80.5ns ± 1% -8.29% (p=0.008 n=5+5) LogFieldType/Object-8 83.7ns ± 2% 77.2ns ± 3% -7.76% (p=0.008 n=5+5) LogFieldType/Bools-8 34.6ns ± 3% 32.3ns ± 6% -6.64% (p=0.032 n=5+5) LogFieldType/Float-8 43.0ns ± 4% 40.5ns ± 4% -5.86% (p=0.016 n=5+5) LogFieldType/Str-8 29.8ns ± 2% 26.5ns ± 5% -11.01% (p=0.008 n=5+5) LogFieldType/Err-8 32.8ns ± 2% 29.8ns ± 4% -9.21% (p=0.008 n=5+5) LogFieldType/Durs-8 309ns ± 3% 304ns ± 3% ~ (p=0.238 n=5+5) LogFieldType/Floats-8 175ns ± 2% 174ns ± 3% ~ (p=0.968 n=5+5) LogFieldType/Strs-8 51.0ns ± 3% 48.4ns ± 6% -5.06% (p=0.032 n=5+5) LogFieldType/Dur-8 44.5ns ± 3% 41.3ns ± 3% -7.11% (p=0.008 n=5+5) LogFieldType/Interface(Objects)-8 758ns ± 3% 760ns ± 6% ~ (p=1.000 n=5+5) LogFieldType/Interfaces-8 772ns ± 5% 762ns ± 4% ~ (p=0.794 n=5+5) LogFieldType/Bool-8 28.0ns ± 6% 26.5ns ± 9% ~ (p=0.143 n=5+5) LogFieldType/Ints-8 49.6ns ± 2% 46.2ns ± 2% -6.70% (p=0.008 n=5+5) LogFieldType/Errs-8 46.5ns ±11% 40.9ns ± 4% -11.92% (p=0.008 n=5+5) LogFieldType/Time-8 115ns ± 3% 113ns ± 3% ~ (p=0.167 n=5+5) LogFieldType/Times-8 810ns ± 1% 811ns ± 3% ~ (p=0.889 n=5+5) ContextFieldType/Errs-8 158ns ± 6% 156ns ±12% ~ (p=1.000 n=5+5) ContextFieldType/Times-8 165ns ±11% 173ns ± 9% ~ (p=0.651 n=5+5) ContextFieldType/Interface-8 289ns ±13% 287ns ±11% ~ (p=0.690 n=5+5) ContextFieldType/Interface(Object)-8 285ns ±12% 297ns ± 6% ~ (p=0.238 n=5+5) ContextFieldType/Interface(Objects)-8 941ns ± 6% 941ns ± 5% ~ (p=1.000 n=5+5) ContextFieldType/Object-8 201ns ± 5% 210ns ±12% ~ (p=0.262 n=5+5) ContextFieldType/Ints-8 173ns ±10% 165ns ± 9% ~ (p=0.198 n=5+5) ContextFieldType/Floats-8 297ns ± 6% 292ns ± 7% ~ (p=0.579 n=5+5) ContextFieldType/Timestamp-8 174ns ± 9% 174ns ±11% ~ (p=0.810 n=5+5) ContextFieldType/Durs-8 445ns ± 9% 425ns ± 3% ~ (p=0.151 n=5+5) ContextFieldType/Interfaces-8 944ns ± 6% 876ns ±10% ~ (p=0.095 n=5+5) ContextFieldType/Strs-8 179ns ±11% 165ns ±13% ~ (p=0.135 n=5+5) ContextFieldType/Dur-8 158ns ± 8% 160ns ±19% ~ (p=1.000 n=5+5) ContextFieldType/Time-8 152ns ±15% 148ns ±14% ~ (p=0.952 n=5+5) ContextFieldType/Str-8 146ns ±12% 147ns ±16% ~ (p=0.841 n=5+5) ContextFieldType/Err-8 138ns ±12% 145ns ±17% ~ (p=0.595 n=5+5) ContextFieldType/Int-8 145ns ±10% 146ns ±13% ~ (p=0.873 n=5+5) ContextFieldType/Float-8 181ns ± 9% 162ns ±12% ~ (p=0.151 n=5+5) ContextFieldType/Bool-8 153ns ±10% 131ns ±19% ~ (p=0.063 n=5+5) ContextFieldType/Bools-8 149ns ±11% 160ns ±16% ~ (p=0.500 n=5+5)
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func (e Encoder) AppendStrings(dst []byte, vals []string) []byte {
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if len(vals) == 0 {
return append(dst, '[', ']')
}
dst = append(dst, '[')
Get back some ns by removing the extra inferance added by binary support benchstat old new name old time/op new time/op delta LogEmpty-8 15.2ns ±14% 13.4ns ± 3% -12.11% (p=0.008 n=5+5) Disabled-8 2.50ns ± 1% 2.28ns ± 6% -8.81% (p=0.008 n=5+5) Info-8 44.4ns ± 1% 36.4ns ± 4% -17.99% (p=0.008 n=5+5) ContextFields-8 47.6ns ± 1% 39.4ns ± 7% -17.30% (p=0.008 n=5+5) ContextAppend-8 18.9ns ± 4% 15.2ns ± 4% -19.68% (p=0.008 n=5+5) LogFields-8 181ns ± 2% 173ns ± 2% -4.63% (p=0.008 n=5+5) LogArrayObject-8 530ns ± 3% 487ns ± 3% -8.11% (p=0.008 n=5+5) LogFieldType/Int-8 29.5ns ± 3% 28.8ns ± 2% ~ (p=0.167 n=5+5) LogFieldType/Interface-8 180ns ± 7% 175ns ± 4% ~ (p=0.579 n=5+5) LogFieldType/Interface(Object)-8 87.8ns ± 3% 80.5ns ± 1% -8.29% (p=0.008 n=5+5) LogFieldType/Object-8 83.7ns ± 2% 77.2ns ± 3% -7.76% (p=0.008 n=5+5) LogFieldType/Bools-8 34.6ns ± 3% 32.3ns ± 6% -6.64% (p=0.032 n=5+5) LogFieldType/Float-8 43.0ns ± 4% 40.5ns ± 4% -5.86% (p=0.016 n=5+5) LogFieldType/Str-8 29.8ns ± 2% 26.5ns ± 5% -11.01% (p=0.008 n=5+5) LogFieldType/Err-8 32.8ns ± 2% 29.8ns ± 4% -9.21% (p=0.008 n=5+5) LogFieldType/Durs-8 309ns ± 3% 304ns ± 3% ~ (p=0.238 n=5+5) LogFieldType/Floats-8 175ns ± 2% 174ns ± 3% ~ (p=0.968 n=5+5) LogFieldType/Strs-8 51.0ns ± 3% 48.4ns ± 6% -5.06% (p=0.032 n=5+5) LogFieldType/Dur-8 44.5ns ± 3% 41.3ns ± 3% -7.11% (p=0.008 n=5+5) LogFieldType/Interface(Objects)-8 758ns ± 3% 760ns ± 6% ~ (p=1.000 n=5+5) LogFieldType/Interfaces-8 772ns ± 5% 762ns ± 4% ~ (p=0.794 n=5+5) LogFieldType/Bool-8 28.0ns ± 6% 26.5ns ± 9% ~ (p=0.143 n=5+5) LogFieldType/Ints-8 49.6ns ± 2% 46.2ns ± 2% -6.70% (p=0.008 n=5+5) LogFieldType/Errs-8 46.5ns ±11% 40.9ns ± 4% -11.92% (p=0.008 n=5+5) LogFieldType/Time-8 115ns ± 3% 113ns ± 3% ~ (p=0.167 n=5+5) LogFieldType/Times-8 810ns ± 1% 811ns ± 3% ~ (p=0.889 n=5+5) ContextFieldType/Errs-8 158ns ± 6% 156ns ±12% ~ (p=1.000 n=5+5) ContextFieldType/Times-8 165ns ±11% 173ns ± 9% ~ (p=0.651 n=5+5) ContextFieldType/Interface-8 289ns ±13% 287ns ±11% ~ (p=0.690 n=5+5) ContextFieldType/Interface(Object)-8 285ns ±12% 297ns ± 6% ~ (p=0.238 n=5+5) ContextFieldType/Interface(Objects)-8 941ns ± 6% 941ns ± 5% ~ (p=1.000 n=5+5) ContextFieldType/Object-8 201ns ± 5% 210ns ±12% ~ (p=0.262 n=5+5) ContextFieldType/Ints-8 173ns ±10% 165ns ± 9% ~ (p=0.198 n=5+5) ContextFieldType/Floats-8 297ns ± 6% 292ns ± 7% ~ (p=0.579 n=5+5) ContextFieldType/Timestamp-8 174ns ± 9% 174ns ±11% ~ (p=0.810 n=5+5) ContextFieldType/Durs-8 445ns ± 9% 425ns ± 3% ~ (p=0.151 n=5+5) ContextFieldType/Interfaces-8 944ns ± 6% 876ns ±10% ~ (p=0.095 n=5+5) ContextFieldType/Strs-8 179ns ±11% 165ns ±13% ~ (p=0.135 n=5+5) ContextFieldType/Dur-8 158ns ± 8% 160ns ±19% ~ (p=1.000 n=5+5) ContextFieldType/Time-8 152ns ±15% 148ns ±14% ~ (p=0.952 n=5+5) ContextFieldType/Str-8 146ns ±12% 147ns ±16% ~ (p=0.841 n=5+5) ContextFieldType/Err-8 138ns ±12% 145ns ±17% ~ (p=0.595 n=5+5) ContextFieldType/Int-8 145ns ±10% 146ns ±13% ~ (p=0.873 n=5+5) ContextFieldType/Float-8 181ns ± 9% 162ns ±12% ~ (p=0.151 n=5+5) ContextFieldType/Bool-8 153ns ±10% 131ns ±19% ~ (p=0.063 n=5+5) ContextFieldType/Bools-8 149ns ±11% 160ns ±16% ~ (p=0.500 n=5+5)
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dst = e.AppendString(dst, vals[0])
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if len(vals) > 1 {
for _, val := range vals[1:] {
Get back some ns by removing the extra inferance added by binary support benchstat old new name old time/op new time/op delta LogEmpty-8 15.2ns ±14% 13.4ns ± 3% -12.11% (p=0.008 n=5+5) Disabled-8 2.50ns ± 1% 2.28ns ± 6% -8.81% (p=0.008 n=5+5) Info-8 44.4ns ± 1% 36.4ns ± 4% -17.99% (p=0.008 n=5+5) ContextFields-8 47.6ns ± 1% 39.4ns ± 7% -17.30% (p=0.008 n=5+5) ContextAppend-8 18.9ns ± 4% 15.2ns ± 4% -19.68% (p=0.008 n=5+5) LogFields-8 181ns ± 2% 173ns ± 2% -4.63% (p=0.008 n=5+5) LogArrayObject-8 530ns ± 3% 487ns ± 3% -8.11% (p=0.008 n=5+5) LogFieldType/Int-8 29.5ns ± 3% 28.8ns ± 2% ~ (p=0.167 n=5+5) LogFieldType/Interface-8 180ns ± 7% 175ns ± 4% ~ (p=0.579 n=5+5) LogFieldType/Interface(Object)-8 87.8ns ± 3% 80.5ns ± 1% -8.29% (p=0.008 n=5+5) LogFieldType/Object-8 83.7ns ± 2% 77.2ns ± 3% -7.76% (p=0.008 n=5+5) LogFieldType/Bools-8 34.6ns ± 3% 32.3ns ± 6% -6.64% (p=0.032 n=5+5) LogFieldType/Float-8 43.0ns ± 4% 40.5ns ± 4% -5.86% (p=0.016 n=5+5) LogFieldType/Str-8 29.8ns ± 2% 26.5ns ± 5% -11.01% (p=0.008 n=5+5) LogFieldType/Err-8 32.8ns ± 2% 29.8ns ± 4% -9.21% (p=0.008 n=5+5) LogFieldType/Durs-8 309ns ± 3% 304ns ± 3% ~ (p=0.238 n=5+5) LogFieldType/Floats-8 175ns ± 2% 174ns ± 3% ~ (p=0.968 n=5+5) LogFieldType/Strs-8 51.0ns ± 3% 48.4ns ± 6% -5.06% (p=0.032 n=5+5) LogFieldType/Dur-8 44.5ns ± 3% 41.3ns ± 3% -7.11% (p=0.008 n=5+5) LogFieldType/Interface(Objects)-8 758ns ± 3% 760ns ± 6% ~ (p=1.000 n=5+5) LogFieldType/Interfaces-8 772ns ± 5% 762ns ± 4% ~ (p=0.794 n=5+5) LogFieldType/Bool-8 28.0ns ± 6% 26.5ns ± 9% ~ (p=0.143 n=5+5) LogFieldType/Ints-8 49.6ns ± 2% 46.2ns ± 2% -6.70% (p=0.008 n=5+5) LogFieldType/Errs-8 46.5ns ±11% 40.9ns ± 4% -11.92% (p=0.008 n=5+5) LogFieldType/Time-8 115ns ± 3% 113ns ± 3% ~ (p=0.167 n=5+5) LogFieldType/Times-8 810ns ± 1% 811ns ± 3% ~ (p=0.889 n=5+5) ContextFieldType/Errs-8 158ns ± 6% 156ns ±12% ~ (p=1.000 n=5+5) ContextFieldType/Times-8 165ns ±11% 173ns ± 9% ~ (p=0.651 n=5+5) ContextFieldType/Interface-8 289ns ±13% 287ns ±11% ~ (p=0.690 n=5+5) ContextFieldType/Interface(Object)-8 285ns ±12% 297ns ± 6% ~ (p=0.238 n=5+5) ContextFieldType/Interface(Objects)-8 941ns ± 6% 941ns ± 5% ~ (p=1.000 n=5+5) ContextFieldType/Object-8 201ns ± 5% 210ns ±12% ~ (p=0.262 n=5+5) ContextFieldType/Ints-8 173ns ±10% 165ns ± 9% ~ (p=0.198 n=5+5) ContextFieldType/Floats-8 297ns ± 6% 292ns ± 7% ~ (p=0.579 n=5+5) ContextFieldType/Timestamp-8 174ns ± 9% 174ns ±11% ~ (p=0.810 n=5+5) ContextFieldType/Durs-8 445ns ± 9% 425ns ± 3% ~ (p=0.151 n=5+5) ContextFieldType/Interfaces-8 944ns ± 6% 876ns ±10% ~ (p=0.095 n=5+5) ContextFieldType/Strs-8 179ns ±11% 165ns ±13% ~ (p=0.135 n=5+5) ContextFieldType/Dur-8 158ns ± 8% 160ns ±19% ~ (p=1.000 n=5+5) ContextFieldType/Time-8 152ns ±15% 148ns ±14% ~ (p=0.952 n=5+5) ContextFieldType/Str-8 146ns ±12% 147ns ±16% ~ (p=0.841 n=5+5) ContextFieldType/Err-8 138ns ±12% 145ns ±17% ~ (p=0.595 n=5+5) ContextFieldType/Int-8 145ns ±10% 146ns ±13% ~ (p=0.873 n=5+5) ContextFieldType/Float-8 181ns ± 9% 162ns ±12% ~ (p=0.151 n=5+5) ContextFieldType/Bool-8 153ns ±10% 131ns ±19% ~ (p=0.063 n=5+5) ContextFieldType/Bools-8 149ns ±11% 160ns ±16% ~ (p=0.500 n=5+5)
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dst = e.AppendString(append(dst, ','), val)
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}
}
dst = append(dst, ']')
return dst
}
// AppendString encodes the input string to json and appends
// the encoded string to the input byte slice.
//
// The operation loops though each byte in the string looking
// for characters that need json or utf8 encoding. If the string
// does not need encoding, then the string is appended in it's
// entirety to the byte slice.
// If we encounter a byte that does need encoding, switch up
// the operation and perform a byte-by-byte read-encode-append.
Get back some ns by removing the extra inferance added by binary support benchstat old new name old time/op new time/op delta LogEmpty-8 15.2ns ±14% 13.4ns ± 3% -12.11% (p=0.008 n=5+5) Disabled-8 2.50ns ± 1% 2.28ns ± 6% -8.81% (p=0.008 n=5+5) Info-8 44.4ns ± 1% 36.4ns ± 4% -17.99% (p=0.008 n=5+5) ContextFields-8 47.6ns ± 1% 39.4ns ± 7% -17.30% (p=0.008 n=5+5) ContextAppend-8 18.9ns ± 4% 15.2ns ± 4% -19.68% (p=0.008 n=5+5) LogFields-8 181ns ± 2% 173ns ± 2% -4.63% (p=0.008 n=5+5) LogArrayObject-8 530ns ± 3% 487ns ± 3% -8.11% (p=0.008 n=5+5) LogFieldType/Int-8 29.5ns ± 3% 28.8ns ± 2% ~ (p=0.167 n=5+5) LogFieldType/Interface-8 180ns ± 7% 175ns ± 4% ~ (p=0.579 n=5+5) LogFieldType/Interface(Object)-8 87.8ns ± 3% 80.5ns ± 1% -8.29% (p=0.008 n=5+5) LogFieldType/Object-8 83.7ns ± 2% 77.2ns ± 3% -7.76% (p=0.008 n=5+5) LogFieldType/Bools-8 34.6ns ± 3% 32.3ns ± 6% -6.64% (p=0.032 n=5+5) LogFieldType/Float-8 43.0ns ± 4% 40.5ns ± 4% -5.86% (p=0.016 n=5+5) LogFieldType/Str-8 29.8ns ± 2% 26.5ns ± 5% -11.01% (p=0.008 n=5+5) LogFieldType/Err-8 32.8ns ± 2% 29.8ns ± 4% -9.21% (p=0.008 n=5+5) LogFieldType/Durs-8 309ns ± 3% 304ns ± 3% ~ (p=0.238 n=5+5) LogFieldType/Floats-8 175ns ± 2% 174ns ± 3% ~ (p=0.968 n=5+5) LogFieldType/Strs-8 51.0ns ± 3% 48.4ns ± 6% -5.06% (p=0.032 n=5+5) LogFieldType/Dur-8 44.5ns ± 3% 41.3ns ± 3% -7.11% (p=0.008 n=5+5) LogFieldType/Interface(Objects)-8 758ns ± 3% 760ns ± 6% ~ (p=1.000 n=5+5) LogFieldType/Interfaces-8 772ns ± 5% 762ns ± 4% ~ (p=0.794 n=5+5) LogFieldType/Bool-8 28.0ns ± 6% 26.5ns ± 9% ~ (p=0.143 n=5+5) LogFieldType/Ints-8 49.6ns ± 2% 46.2ns ± 2% -6.70% (p=0.008 n=5+5) LogFieldType/Errs-8 46.5ns ±11% 40.9ns ± 4% -11.92% (p=0.008 n=5+5) LogFieldType/Time-8 115ns ± 3% 113ns ± 3% ~ (p=0.167 n=5+5) LogFieldType/Times-8 810ns ± 1% 811ns ± 3% ~ (p=0.889 n=5+5) ContextFieldType/Errs-8 158ns ± 6% 156ns ±12% ~ (p=1.000 n=5+5) ContextFieldType/Times-8 165ns ±11% 173ns ± 9% ~ (p=0.651 n=5+5) ContextFieldType/Interface-8 289ns ±13% 287ns ±11% ~ (p=0.690 n=5+5) ContextFieldType/Interface(Object)-8 285ns ±12% 297ns ± 6% ~ (p=0.238 n=5+5) ContextFieldType/Interface(Objects)-8 941ns ± 6% 941ns ± 5% ~ (p=1.000 n=5+5) ContextFieldType/Object-8 201ns ± 5% 210ns ±12% ~ (p=0.262 n=5+5) ContextFieldType/Ints-8 173ns ±10% 165ns ± 9% ~ (p=0.198 n=5+5) ContextFieldType/Floats-8 297ns ± 6% 292ns ± 7% ~ (p=0.579 n=5+5) ContextFieldType/Timestamp-8 174ns ± 9% 174ns ±11% ~ (p=0.810 n=5+5) ContextFieldType/Durs-8 445ns ± 9% 425ns ± 3% ~ (p=0.151 n=5+5) ContextFieldType/Interfaces-8 944ns ± 6% 876ns ±10% ~ (p=0.095 n=5+5) ContextFieldType/Strs-8 179ns ±11% 165ns ±13% ~ (p=0.135 n=5+5) ContextFieldType/Dur-8 158ns ± 8% 160ns ±19% ~ (p=1.000 n=5+5) ContextFieldType/Time-8 152ns ±15% 148ns ±14% ~ (p=0.952 n=5+5) ContextFieldType/Str-8 146ns ±12% 147ns ±16% ~ (p=0.841 n=5+5) ContextFieldType/Err-8 138ns ±12% 145ns ±17% ~ (p=0.595 n=5+5) ContextFieldType/Int-8 145ns ±10% 146ns ±13% ~ (p=0.873 n=5+5) ContextFieldType/Float-8 181ns ± 9% 162ns ±12% ~ (p=0.151 n=5+5) ContextFieldType/Bool-8 153ns ±10% 131ns ±19% ~ (p=0.063 n=5+5) ContextFieldType/Bools-8 149ns ±11% 160ns ±16% ~ (p=0.500 n=5+5)
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func (Encoder) AppendString(dst []byte, s string) []byte {
// Start with a double quote.
dst = append(dst, '"')
// Loop through each character in the string.
for i := 0; i < len(s); i++ {
// Check if the character needs encoding. Control characters, slashes,
// and the double quote need json encoding. Bytes above the ascii
// boundary needs utf8 encoding.
if !noEscapeTable[s[i]] {
// We encountered a character that needs to be encoded. Switch
// to complex version of the algorithm.
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dst = appendStringComplex(dst, s, i)
return append(dst, '"')
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}
}
// The string has no need for encoding an therefore is directly
// appended to the byte slice.
dst = append(dst, s...)
// End with a double quote
return append(dst, '"')
}
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// appendStringComplex is used by appendString to take over an in
// progress JSON string encoding that encountered a character that needs
// to be encoded.
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func appendStringComplex(dst []byte, s string, i int) []byte {
start := 0
for i < len(s) {
b := s[i]
if b >= utf8.RuneSelf {
r, size := utf8.DecodeRuneInString(s[i:])
if r == utf8.RuneError && size == 1 {
// In case of error, first append previous simple characters to
// the byte slice if any and append a remplacement character code
// in place of the invalid sequence.
if start < i {
dst = append(dst, s[start:i]...)
}
dst = append(dst, `\ufffd`...)
i += size
start = i
continue
}
i += size
continue
}
if noEscapeTable[b] {
i++
continue
}
// We encountered a character that needs to be encoded.
// Let's append the previous simple characters to the byte slice
// and switch our operation to read and encode the remainder
// characters byte-by-byte.
if start < i {
dst = append(dst, s[start:i]...)
}
switch b {
case '"', '\\':
dst = append(dst, '\\', b)
case '\b':
dst = append(dst, '\\', 'b')
case '\f':
dst = append(dst, '\\', 'f')
case '\n':
dst = append(dst, '\\', 'n')
case '\r':
dst = append(dst, '\\', 'r')
case '\t':
dst = append(dst, '\\', 't')
default:
dst = append(dst, '\\', 'u', '0', '0', hex[b>>4], hex[b&0xF])
}
i++
start = i
}
if start < len(s) {
dst = append(dst, s[start:]...)
}
return dst
}