math/rand/v2, math/big: use internal/byteorder

Change-Id: Id07f16d14133ee539bc2880b39641c42418fa6e2
GitHub-Last-Rev: 7b327d508f677f2476d24f046d25921f4599dd9a
GitHub-Pull-Request: golang/go#67319
Reviewed-on: https://go-review.googlesource.com/c/go/+/585016
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

5 files changed, 17 insertions, 36 deletions

diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index 44976c7356..537de94a75 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -249,7 +249,7 @@ var depsRules = `
 	< hash/adler32, hash/crc32, hash/crc64, hash/fnv;
 
 	# math/big
-	FMT, encoding/binary, math/rand
+	FMT, math/rand
 	< math/big;
 
 	# compression
diff --git a/src/math/big/floatmarsh.go b/src/math/big/floatmarsh.go
index 8a908cef28..16be946971 100644
--- a/src/math/big/floatmarsh.go
+++ b/src/math/big/floatmarsh.go
@@ -7,9 +7,9 @@
 package big
 
 import (
-	"encoding/binary"
 	"errors"
 	"fmt"
+	"internal/byteorder"
 )
 
 // Gob codec version. Permits backward-compatible changes to the encoding.
@@ -48,10 +48,10 @@ func (x *Float) GobEncode() ([]byte, error) {
 		b |= 1
 	}
 	buf[1] = b
-	binary.BigEndian.PutUint32(buf[2:], x.prec)
+	byteorder.BePutUint32(buf[2:], x.prec)
 
 	if x.form == finite {
-		binary.BigEndian.PutUint32(buf[6:], uint32(x.exp))
+		byteorder.BePutUint32(buf[6:], uint32(x.exp))
 		x.mant[len(x.mant)-n:].bytes(buf[10:]) // cut off unused trailing words
 	}
 
@@ -84,13 +84,13 @@ func (z *Float) GobDecode(buf []byte) error {
 	z.acc = Accuracy((b>>3)&3) - 1
 	z.form = form((b >> 1) & 3)
 	z.neg = b&1 != 0
-	z.prec = binary.BigEndian.Uint32(buf[2:])
+	z.prec = byteorder.BeUint32(buf[2:])
 
 	if z.form == finite {
 		if len(buf) < 10 {
 			return errors.New("Float.GobDecode: buffer too small for finite form float")
 		}
-		z.exp = int32(binary.BigEndian.Uint32(buf[6:]))
+		z.exp = int32(byteorder.BeUint32(buf[6:]))
 		z.mant = z.mant.setBytes(buf[10:])
 	}
 
diff --git a/src/math/big/nat.go b/src/math/big/nat.go
index 1d702c7726..23b2a0b8dd 100644
--- a/src/math/big/nat.go
+++ b/src/math/big/nat.go
@@ -14,7 +14,7 @@
 package big
 
 import (
-	"encoding/binary"
+	"internal/byteorder"
 	"math/bits"
 	"math/rand"
 	"sync"
@@ -1321,9 +1321,9 @@ func (z nat) bytes(buf []byte) (i int) {
 // bigEndianWord returns the contents of buf interpreted as a big-endian encoded Word value.
 func bigEndianWord(buf []byte) Word {
 	if _W == 64 {
-		return Word(binary.BigEndian.Uint64(buf))
+		return Word(byteorder.BeUint64(buf))
 	}
-	return Word(binary.BigEndian.Uint32(buf))
+	return Word(byteorder.BeUint32(buf))
 }
 
 // setBytes interprets buf as the bytes of a big-endian unsigned
diff --git a/src/math/big/ratmarsh.go b/src/math/big/ratmarsh.go
index 033fb4459d..6962829453 100644
--- a/src/math/big/ratmarsh.go
+++ b/src/math/big/ratmarsh.go
@@ -7,9 +7,9 @@
 package big
 
 import (
-	"encoding/binary"
 	"errors"
 	"fmt"
+	"internal/byteorder"
 	"math"
 )
 
@@ -29,7 +29,7 @@ func (x *Rat) GobEncode() ([]byte, error) {
 		// this should never happen
 		return nil, errors.New("Rat.GobEncode: numerator too large")
 	}
-	binary.BigEndian.PutUint32(buf[j-4:j], uint32(n))
+	byteorder.BePutUint32(buf[j-4:j], uint32(n))
 	j -= 1 + 4
 	b := ratGobVersion << 1 // make space for sign bit
 	if x.a.neg {
@@ -54,7 +54,7 @@ func (z *Rat) GobDecode(buf []byte) error {
 		return fmt.Errorf("Rat.GobDecode: encoding version %d not supported", b>>1)
 	}
 	const j = 1 + 4
-	ln := binary.BigEndian.Uint32(buf[j-4 : j])
+	ln := byteorder.BeUint32(buf[j-4 : j])
 	if uint64(ln) > math.MaxInt-j {
 		return errors.New("Rat.GobDecode: invalid length")
 	}
diff --git a/src/math/rand/v2/pcg.go b/src/math/rand/v2/pcg.go
index 77708d799e..4ccd5e320b 100644
--- a/src/math/rand/v2/pcg.go
+++ b/src/math/rand/v2/pcg.go
@@ -6,6 +6,7 @@ package rand
 
 import (
 	"errors"
+	"internal/byteorder"
 	"math/bits"
 )
 
@@ -30,32 +31,12 @@ func (p *PCG) Seed(seed1, seed2 uint64) {
 	p.lo = seed2
 }
 
-// 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)
-}
-
 // MarshalBinary implements the encoding.BinaryMarshaler interface.
 func (p *PCG) MarshalBinary() ([]byte, error) {
 	b := make([]byte, 20)
 	copy(b, "pcg:")
-	bePutUint64(b[4:], p.hi)
-	bePutUint64(b[4+8:], p.lo)
+	byteorder.BePutUint64(b[4:], p.hi)
+	byteorder.BePutUint64(b[4+8:], p.lo)
 	return b, nil
 }
 
@@ -66,8 +47,8 @@ func (p *PCG) UnmarshalBinary(data []byte) error {
 	if len(data) != 20 || string(data[:4]) != "pcg:" {
 		return errUnmarshalPCG
 	}
-	p.hi = beUint64(data[4:])
-	p.lo = beUint64(data[4+8:])
+	p.hi = byteorder.BeUint64(data[4:])
+	p.lo = byteorder.BeUint64(data[4+8:])
 	return nil
 }