internal/chacha8rand: use internal/byteorder

Change-Id: Ia5bcaba47da949583a720ca3506d6bd9e3794824
GitHub-Last-Rev: 1ed3dad2bf
GitHub-Pull-Request: golang/go#67320
Reviewed-on: https://go-review.googlesource.com/c/go/+/584996
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/cmd/internal/objabi/pkgspecial.go

@@ -50,6 +50,7 @@ var runtimePkgs = []string{
 
 	"internal/abi",
 	"internal/bytealg",
+	"internal/byteorder",
 	"internal/chacha8rand",
 	"internal/coverage/rtcov",
 	"internal/cpu",

src/go/build/deps_test.go

@@ -43,16 +43,17 @@ var depsRules = `
 	  internal/cfg, internal/coverage, internal/coverage/rtcov,
 	  internal/coverage/uleb128, internal/coverage/calloc,
 	  internal/cpu, internal/goarch, internal/godebugs,
-	  internal/goexperiment, internal/goos,
+	  internal/goexperiment, internal/goos, internal/byteorder,
 	  internal/goversion, internal/nettrace, internal/platform,
 	  internal/trace/traceviewer/format,
 	  log/internal,
 	  unicode/utf8, unicode/utf16, unicode,
 	  unsafe;
 
-	# These packages depend only on internal/goarch and unsafe.
+	# internal/abi depends only on internal/goarch and unsafe.
-	internal/goarch, unsafe
+	internal/goarch, unsafe < internal/abi;
-	< internal/abi, internal/chacha8rand;
+
+	internal/byteorder, internal/goarch, unsafe < internal/chacha8rand;
 
 	unsafe < maps;
 
@@ -67,7 +68,6 @@ var depsRules = `
 	internal/goos
 	< internal/bytealg
 	< internal/stringslite
-	< internal/byteorder
 	< internal/itoa
 	< internal/unsafeheader
 	< runtime/internal/sys

src/internal/chacha8rand/chacha8.go

@@ -4,9 +4,11 @@
 
 // Package chacha8rand implements a pseudorandom generator
 // based on ChaCha8. It is used by both runtime and math/rand/v2
-// and must have no dependencies.
+// and must have minimal dependencies.
 package chacha8rand
 
+import "internal/byteorder"
+
 const (
 	ctrInc = 4  // increment counter by 4 between block calls
 	ctrMax = 16 // reseed when counter reaches 16
@@ -51,10 +53,10 @@ func (s *State) Next() (uint64, bool) {
 // Init seeds the State with the given seed value.
 func (s *State) Init(seed [32]byte) {
 	s.Init64([4]uint64{
-		leUint64(seed[0*8:]),
+		byteorder.LeUint64(seed[0*8:]),
-		leUint64(seed[1*8:]),
+		byteorder.LeUint64(seed[1*8:]),
-		leUint64(seed[2*8:]),
+		byteorder.LeUint64(seed[2*8:]),
-		leUint64(seed[3*8:]),
+		byteorder.LeUint64(seed[3*8:]),
 	})
 }
 
@@ -122,9 +124,9 @@ func Marshal(s *State) []byte {
 	data := make([]byte, 6*8)
 	copy(data, "chacha8:")
 	used := (s.c/ctrInc)*chunk + s.i
-	bePutUint64(data[1*8:], uint64(used))
+	byteorder.BePutUint64(data[1*8:], uint64(used))
 	for i, seed := range s.seed {
-		lePutUint64(data[(2+i)*8:], seed)
+		byteorder.LePutUint64(data[(2+i)*8:], seed)
 	}
 	return data
 }
@@ -140,12 +142,12 @@ func Unmarshal(s *State, data []byte) error {
 	if len(data) != 6*8 || string(data[:8]) != "chacha8:" {
 		return new(errUnmarshalChaCha8)
 	}
-	used := beUint64(data[1*8:])
+	used := byteorder.BeUint64(data[1*8:])
 	if used > (ctrMax/ctrInc)*chunk-reseed {
 		return new(errUnmarshalChaCha8)
 	}
 	for i := range s.seed {
-		s.seed[i] = leUint64(data[(2+i)*8:])
+		s.seed[i] = byteorder.LeUint64(data[(2+i)*8:])
 	}
 	s.c = ctrInc * (uint32(used) / chunk)
 	block(&s.seed, &s.buf, s.c)
@@ -156,43 +158,3 @@ func Unmarshal(s *State, data []byte) error {
 	}
 	return nil
 }
-
-// binary.bigEndian.Uint64, copied to avoid dependency
-func beUint64(b []byte) uint64 {
-	_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
-	return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
-		uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
-}
-
-// binary.bigEndian.PutUint64, copied to avoid dependency
-func bePutUint64(b []byte, v uint64) {
-	_ = b[7] // early bounds check to guarantee safety of writes below
-	b[0] = byte(v >> 56)
-	b[1] = byte(v >> 48)
-	b[2] = byte(v >> 40)
-	b[3] = byte(v >> 32)
-	b[4] = byte(v >> 24)
-	b[5] = byte(v >> 16)
-	b[6] = byte(v >> 8)
-	b[7] = byte(v)
-}
-
-// binary.littleEndian.Uint64, copied to avoid dependency
-func leUint64(b []byte) uint64 {
-	_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
-	return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
-		uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
-}
-
-// binary.littleEndian.PutUint64, copied to avoid dependency
-func lePutUint64(b []byte, v uint64) {
-	_ = b[7] // early bounds check to guarantee safety of writes below
-	b[0] = byte(v)
-	b[1] = byte(v >> 8)
-	b[2] = byte(v >> 16)
-	b[3] = byte(v >> 24)
-	b[4] = byte(v >> 32)
-	b[5] = byte(v >> 40)
-	b[6] = byte(v >> 48)
-	b[7] = byte(v >> 56)
-}