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Add AppendInt function with positive/negative number convertion to string #90

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Add AppendInt function with positive/negative number convertion to string #90

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e60c5a7
Add AppendInt function with positive/negative number convertion to st…
ReneWerner87 Jul 21, 2024
87790b8
Add AppendInt function with positive/negative number convertion to st…
ReneWerner87 Jul 21, 2024
9c0bea3
Add AppendInt function with positive/negative number convertion to st…
ReneWerner87 Jul 21, 2024
ac59843
Add AppendInt function with positive/negative number convertion to st…
ReneWerner87 Jul 21, 2024
14f52bc
Add AppendInt function with positive/negative number convertion to st…
ReneWerner87 Jul 22, 2024
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16 changes: 15 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ pkg: github.com/gofiber/utils
cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz

```go
// go test -benchmem -run=^$ -bench=Benchmark_ -count=2
// go test -benchmem -run=^$ -bench=Benchmark_ -count=2

Benchmark_ToLowerBytes/fiber-12 29715831 36.44 ns/op 0 B/op 0 allocs/op
Benchmark_ToLowerBytes/fiber-12 33316479 36.28 ns/op 0 B/op 0 allocs/op
Expand Down Expand Up @@ -60,6 +60,19 @@ Benchmark_UnsafeBytes/default-12 52615048 22.33 ns/op
Benchmark_ToString-12 22981430 51.72 ns/op 40 B/op 2 allocs/op
Benchmark_ToString-12 22956476 52.93 ns/op 40 B/op 2 allocs/op

Benchmark_ItoA/fiber (pos_num)-12 186969812 6.25 ns/op 0 B/op 0 allocs/op
Benchmark_ItoA/fiber (pos_num)-12 193965686 6.16 ns/op 0 B/op 0 allocs/op
Benchmark_ItoA/strconv.Itoa (pos_num)-12 80716807 14.42 ns/op 4 B/op 1 allocs/op
Benchmark_ItoA/strconv.Itoa (pos_num)-12 80445802 14.85 ns/op 4 B/op 1 allocs/op
Benchmark_ItoA/strconv.FormatInt_(pos_num)-12 81137728 14.52 ns/op 4 B/op 1 allocs/op
Benchmark_ItoA/strconv.FormatInt_(pos_num)-12 81345360 14.51 ns/op 4 B/op 1 allocs/op
Benchmark_ItoA/fiber (neg_num)-12 192902048 6.18 ns/op 0 B/op 0 allocs/op
Benchmark_ItoA/fiber (neg_num)-12 194245189 6.14 ns/op 0 B/op 0 allocs/op
Benchmark_ItoA/strconv.Itoa (neg_num)-12 84505304 13.55 ns/op 5 B/op 1 allocs/op
Benchmark_ItoA/strconv.Itoa (neg_num)-12 82524801 13.54 ns/op 5 B/op 1 allocs/op
Benchmark_ItoA/strconv.FormatInt (neg_num)-12 84884136 13.63 ns/op 5 B/op 1 allocs/op
Benchmark_ItoA/strconv.FormatInt (neg_num)-12 85829492 13.63 ns/op 5 B/op 1 allocs/op

Benchmark_GetMIME/fiber-12 15782622 74.99 ns/op 0 B/op 0 allocs/op
Benchmark_GetMIME/fiber-12 13992375 93.13 ns/op 0 B/op 0 allocs/op
Benchmark_GetMIME/default-12 6825952 147.0 ns/op 0 B/op 0 allocs/op
Expand Down Expand Up @@ -100,6 +113,7 @@ Benchmark_CalculateTimestamp/fiber-12 1000000000 0.2634 ns/op
Benchmark_CalculateTimestamp/fiber-12 1000000000 0.2935 ns/op 0 B/op 0 allocs/op
Benchmark_CalculateTimestamp/default-12 15740576 73.79 ns/op 0 B/op 0 allocs/op
Benchmark_CalculateTimestamp/default-12 15789036 71.12 ns/op 0 B/op 0 allocs/op

```

See all the benchmarks under https://gofiber.github.io/utils/
31 changes: 31 additions & 0 deletions convert.go
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Expand Up @@ -151,3 +151,34 @@ func ToString(arg any, timeFormat ...string) string {
return fmt.Sprint(arg)
}
}

// AppendInt appends the string representation of the int n to dst and returns the extended buffer.
func AppendInt(dst []byte, n int) []byte {
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I think we need a separate function for AppendUint that uses uint as param, else we won't be able to handle values bigger than 2,147,483,647

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The math module in Golang defines these:

MaxUint32 = 1<<32 - 1           // 4294967295
MaxUint64 = 1<<64 - 1           // 18446744073709551615

isNegative := n < 0
if isNegative {
// Convert the number to positive
n = -n
}
Comment on lines +156 to +161
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Correctness: Handle integer overflow for negative values.

When converting a negative integer to positive, be cautious of integer overflow. The edge case for n = math.MinInt should be handled.

if isNegative {
	if n == math.MinInt {
		// Handle the edge case for the smallest possible integer
		dst = append(dst, "-9223372036854775808"...)
		return dst
	}
	n = -n
}


var b [20]byte
buf := b[:]
i := len(buf)
var q int
for n >= 10 {
i--
q = n / 10
buf[i] = '0' + byte(n-q*10)
n = q
}
i--
buf[i] = '0' + byte(n)

if isNegative {
// add '-' in front of the number
dst = append(dst, '-')
}

dst = append(dst, buf[i:]...)

return dst
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}
81 changes: 81 additions & 0 deletions convert_test.go
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Expand Up @@ -6,6 +6,7 @@ package utils

import (
"reflect"
"strconv"
"testing"
"time"

Expand Down Expand Up @@ -232,6 +233,19 @@ func TestByteSize(t *testing.T) {
}
}

func Test_AppendInt(t *testing.T) {
t.Parallel()

dst := make([]byte, 0)

require.Equal(t, []byte("42"), AppendInt(dst, 42))
require.Equal(t, []byte("1500"), AppendInt(dst, 1500))
require.Equal(t, []byte("0"), AppendInt(dst, 0))
require.Equal(t, []byte("-1"), AppendInt(dst, -1))
require.Equal(t, []byte("-2"), AppendInt(dst, -2))
require.Equal(t, []byte("-4500"), AppendInt(dst, -4500))
}

// go test -v -run=^$ -bench=ToString -benchmem -count=4
func Benchmark_ToString(b *testing.B) {
for _, value := range dataTypeExamples {
Expand Down Expand Up @@ -295,3 +309,70 @@ func Benchmark_UnsafeString(b *testing.B) {
require.Equal(b, "Hello, World!", res)
})
}

// go test -v -run=^$ -bench=ItoA -benchmem -count=4
func Benchmark_ItoA(b *testing.B) {
number := 4242
number64 := int64(number)
numberString := "4242"
numberN := -4242
number64N := int64(numberN)
numberNString := "-4242"

var resB []byte
var resS string
b.Run("fiber (positiv number)", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()

for n := 0; n < b.N; n++ {
resB = AppendInt(resB[:0], number)
}
require.Equal(b, []byte(numberString), resB)
})

b.Run("default - strconv.Itoa (positiv number)", func(b *testing.B) {
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positive*

b.ReportAllocs()
b.ResetTimer()
for n := 0; n < b.N; n++ {
resS = strconv.Itoa(number)
}
require.Equal(b, numberString, resS)
})

b.Run("default - strconv.FormatInt (positiv number)", func(b *testing.B) {
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positive*

b.ReportAllocs()
b.ResetTimer()
for n := 0; n < b.N; n++ {
resS = strconv.FormatInt(number64, 10)
}
require.Equal(b, numberString, resS)
})

b.Run("fiber (negative number)", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
for n := 0; n < b.N; n++ {
resB = AppendInt(resB[:0], numberN)
}
require.Equal(b, []byte(numberNString), resB)
})

b.Run("default - strconv.Itoa (negative number)", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
for n := 0; n < b.N; n++ {
resS = strconv.Itoa(numberN)
}
require.Equal(b, numberNString, resS)
})

b.Run("default - strconv.FormatInt (negative number)", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
for n := 0; n < b.N; n++ {
resS = strconv.FormatInt(number64N, 10)
}
require.Equal(b, numberNString, resS)
})
}
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