for the lulz

rusq · Oct 12, 2024 · b55b0ac · b55b0ac
1 parent 8260bed
commit b55b0ac
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diff --git a/internal/fasttime/benchmarks.adoc b/internal/fasttime/benchmarks.adoc
@@ -0,0 +1,48 @@
+= BenchmarkTs2Int
+
+== i7-4600U
+=== 32bit
+
+[source]
+---
+PS C:\slackdump\internal\fasttime>go test . -bench ".*" -count=10
+goos: windows
+goarch: 386
+pkg: github.com/rusq/slackdump/v3/internal/fasttime
+cpu: Intel(R) Core(TM) i7-4600U CPU @ 2.10GHz
+BenchmarkTs2Int-4        3084236               388.5 ns/op
+BenchmarkTs2Int-4        3130807               379.5 ns/op
+BenchmarkTs2Int-4        3134098               382.9 ns/op
+BenchmarkTs2Int-4        3142426               378.4 ns/op
+BenchmarkTs2Int-4        3133819               382.8 ns/op
+BenchmarkTs2Int-4        3152484               376.7 ns/op
+BenchmarkTs2Int-4        3076028               377.8 ns/op
+BenchmarkTs2Int-4        3143527               379.2 ns/op
+BenchmarkTs2Int-4        3134566               380.1 ns/op
+BenchmarkTs2Int-4        3152730               378.8 ns/op
+PASS
+ok      github.com/rusq/slackdump/v3/internal/fasttime  16.000s
+---
+
+=== 64bit
+
+[source]
+---   
+PS C:\slackdump\internal\fasttime> go test . -bench ".*" -count=10
+goos: windows
+goarch: amd64
+pkg: github.com/rusq/slackdump/v3/internal/fasttime
+cpu: Intel(R) Core(TM) i7-4600U CPU @ 2.10GHz
+BenchmarkTs2Int-4       15718426                73.29 ns/op
+BenchmarkTs2Int-4       16554610                72.74 ns/op
+BenchmarkTs2Int-4       13828022                73.78 ns/op
+BenchmarkTs2Int-4       14210768                72.53 ns/op
+BenchmarkTs2Int-4       14328169                74.43 ns/op
+BenchmarkTs2Int-4       16349811                72.58 ns/op
+BenchmarkTs2Int-4       16485547                72.99 ns/op
+BenchmarkTs2Int-4       16368154                72.58 ns/op
+BenchmarkTs2Int-4       13619184                73.89 ns/op
+BenchmarkTs2Int-4       16509716                72.28 ns/op
+PASS
+ok      github.com/rusq/slackdump/v3/internal/fasttime  18.064s
+---
diff --git a/internal/fasttime/fasttime.go b/internal/fasttime/fasttime.go
@@ -46,7 +46,7 @@ func TS2int(ts string) (int64, error) {
 	if i == -1 {
 		return 0, fmt.Errorf("%w: %q", ErrNotATimestamp, ts)
 	}
-	val, err := strconv.ParseUint(ts[:i]+ts[i+1:], 10, 64)
+	val, err := atoi(ts[:i] + ts[i+1:])
 	return int64(val), err
 }
 

diff --git a/internal/fasttime/fasttime_386.go b/internal/fasttime/fasttime_386.go
@@ -0,0 +1,9 @@
+//go:build 386
+
+package fasttime
+
+import "strconv"
+
+// int size on the 32-bit systems is 32 bit (surprise), this constraints us to slower 64-bit implementation.
+
+var atoi = func(s string) (int64, error) { return strconv.ParseInt(s, 10, 64) }
diff --git a/internal/fasttime/fasttime_test.go b/internal/fasttime/fasttime_test.go
@@ -1,7 +1,9 @@
 package fasttime
 
 import (
+	"math"
 	"reflect"
+	"strconv"
 	"testing"
 	"time"
 )
@@ -34,6 +36,12 @@ func TestTs2int(t *testing.T) {
 			1674255434388009,
 			false,
 		},
+		{
+			"maxint64",
+			args{strconv.FormatInt(math.MaxInt64/1000, 10) + ".000"},
+			math.MaxInt64 / 1000 * 1000,
+			false,
+		},
 		{
 			"no dot",
 			args{"1674255434"},

diff --git a/internal/fasttime/fasttime_x64.go b/internal/fasttime/fasttime_x64.go
@@ -0,0 +1,9 @@
+//go:build !386
+
+package fasttime
+
+import "strconv"
+
+// As int on 64-bit systems is 64 bit, it is possible to use faster Atoi.
+
+var atoi = strconv.Atoi