nuke/monotoniic: reset's behavior and a little bit of improvements

go.mod

@@ -1,8 +1,8 @@
 module github.com/ortuman/nuke
 
-go 1.21.7
+go 1.21.8
 
-require github.com/stretchr/testify v1.8.4
+require github.com/stretchr/testify v1.9.0
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect

go.sum

@@ -2,8 +2,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

monotonic_arena.go

@@ -26,8 +26,8 @@ func (s *monotonicBuffer) alloc(size, alignment uintptr) (unsafe.Pointer, bool)
 		s.ptr = unsafe.Pointer(unsafe.SliceData(buf))
 	}
 	alignOffset := uintptr(0)
-	for alignedPtr := uintptr(s.ptr) + s.offset; alignedPtr%alignment != 0; alignedPtr++ {
-		alignOffset++
+	if delta := (uintptr(s.ptr) + s.offset) % alignment; delta > 0 {
+		alignOffset = alignment - delta
 	}
 	allocSize := size + alignOffset
 
@@ -37,15 +37,7 @@ func (s *monotonicBuffer) alloc(size, alignment uintptr) (unsafe.Pointer, bool)
 	ptr := unsafe.Pointer(uintptr(s.ptr) + s.offset + alignOffset)
 	s.offset += allocSize
 
-	// This piece of code will be translated into a runtime.memclrNoHeapPointers
-	// invocation by the compiler, which is an assembler optimized implementation.
-	// Architecture specific code can be found at src/runtime/memclr_$GOARCH.s
-	// in Go source (since https://codereview.appspot.com/137880043).
-	b := unsafe.Slice((*byte)(ptr), size)
-
-	for i := range b {
-		b[i] = 0
-	}
+	clear(unsafe.Slice((*byte)(ptr), size))
 
 	return ptr, true
 }
@@ -67,7 +59,7 @@ func (s *monotonicBuffer) availableBytes() uintptr {
 
 // NewMonotonicArena creates a new monotonic arena with a specified number of buffers and a buffer size.
 func NewMonotonicArena(bufferSize, bufferCount int) Arena {
-	a := &monotonicArena{}
+	a := &monotonicArena{buffers: make([]*monotonicBuffer, 0, bufferCount)}
 	for i := 0; i < bufferCount; i++ {
 		a.buffers = append(a.buffers, newMonotonicBuffer(bufferSize))
 	}
@@ -76,7 +68,7 @@ func NewMonotonicArena(bufferSize, bufferCount int) Arena {
 
 // Alloc satisfies the Arena interface.
 func (a *monotonicArena) Alloc(size, alignment uintptr) unsafe.Pointer {
-	for i := 0; i < len(a.buffers); i++ {
+	for i := range a.buffers {
 		ptr, ok := a.buffers[i].alloc(size, alignment)
 		if ok {
 			return ptr
@@ -87,7 +79,7 @@ func (a *monotonicArena) Alloc(size, alignment uintptr) unsafe.Pointer {
 
 // Reset satisfies the Arena interface.
 func (a *monotonicArena) Reset(release bool) {
-	for _, s := range a.buffers {
-		s.reset(release)
+	for i := range a.buffers {
+		a.buffers[i].reset(release)
 	}
 }