common/math: delete some further dead code (#30639)

Author: karalabe

common/math/big.go

@@ -24,12 +24,9 @@ import (
 
 // Various big integer limit values.
 var (
-	tt255     = BigPow(2, 255)
 	tt256     = BigPow(2, 256)
 	tt256m1   = new(big.Int).Sub(tt256, big.NewInt(1))
-	tt63      = BigPow(2, 63)
 	MaxBig256 = new(big.Int).Set(tt256m1)
-	MaxBig63  = new(big.Int).Sub(tt63, big.NewInt(1))
 )
 
 const (
@@ -162,16 +159,6 @@ func BigMin(x, y *big.Int) *big.Int {
 	return x
 }
 
-// FirstBitSet returns the index of the first 1 bit in v, counting from LSB.
-func FirstBitSet(v *big.Int) int {
-	for i := 0; i < v.BitLen(); i++ {
-		if v.Bit(i) > 0 {
-			return i
-		}
-	}
-	return v.BitLen()
-}
-
 // PaddedBigBytes encodes a big integer as a big-endian byte slice. The length
 // of the slice is at least n bytes.
 func PaddedBigBytes(bigint *big.Int, n int) []byte {
@@ -183,34 +170,6 @@ func PaddedBigBytes(bigint *big.Int, n int) []byte {
 	return ret
 }
 
-// bigEndianByteAt returns the byte at position n,
-// in Big-Endian encoding
-// So n==0 returns the least significant byte
-func bigEndianByteAt(bigint *big.Int, n int) byte {
-	words := bigint.Bits()
-	// Check word-bucket the byte will reside in
-	i := n / wordBytes
-	if i >= len(words) {
-		return byte(0)
-	}
-	word := words[i]
-	// Offset of the byte
-	shift := 8 * uint(n%wordBytes)
-
-	return byte(word >> shift)
-}
-
-// Byte returns the byte at position n,
-// with the supplied padlength in Little-Endian encoding.
-// n==0 returns the MSB
-// Example: bigint '5', padlength 32, n=31 => 5
-func Byte(bigint *big.Int, padlength, n int) byte {
-	if n >= padlength {
-		return byte(0)
-	}
-	return bigEndianByteAt(bigint, padlength-1-n)
-}
-
 // ReadBits encodes the absolute value of bigint as big-endian bytes. Callers must ensure
 // that buf has enough space. If buf is too short the result will be incomplete.
 func ReadBits(bigint *big.Int, buf []byte) {

common/math/big_test.go

@@ -21,8 +21,6 @@ import (
 	"encoding/hex"
 	"math/big"
 	"testing"
-
-	"github.com/ethereum/go-ethereum/common"
 )
 
 func TestHexOrDecimal256(t *testing.T) {
@@ -100,23 +98,6 @@ func TestBigMin(t *testing.T) {
 	}
 }
 
-func TestFirstBigSet(t *testing.T) {
-	tests := []struct {
-		num *big.Int
-		ix  int
-	}{
-		{big.NewInt(0), 0},
-		{big.NewInt(1), 0},
-		{big.NewInt(2), 1},
-		{big.NewInt(0x100), 8},
-	}
-	for _, test := range tests {
-		if ix := FirstBitSet(test.num); ix != test.ix {
-			t.Errorf("FirstBitSet(b%b) = %d, want %d", test.num, ix, test.ix)
-		}
-	}
-}
-
 func TestPaddedBigBytes(t *testing.T) {
 	tests := []struct {
 		num    *big.Int
@@ -220,60 +201,3 @@ func TestU256Bytes(t *testing.T) {
 		t.Errorf("expected %x got %x", ubytes, unsigned)
 	}
 }
-
-func TestBigEndianByteAt(t *testing.T) {
-	tests := []struct {
-		x   string
-		y   int
-		exp byte
-	}{
-		{"00", 0, 0x00},
-		{"01", 1, 0x00},
-		{"00", 1, 0x00},
-		{"01", 0, 0x01},
-		{"0000000000000000000000000000000000000000000000000000000000102030", 0, 0x30},
-		{"0000000000000000000000000000000000000000000000000000000000102030", 1, 0x20},
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 31, 0xAB},
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 32, 0x00},
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 500, 0x00},
-	}
-	for _, test := range tests {
-		v := new(big.Int).SetBytes(common.Hex2Bytes(test.x))
-		actual := bigEndianByteAt(v, test.y)
-		if actual != test.exp {
-			t.Fatalf("Expected  [%v] %v:th byte to be %v, was %v.", test.x, test.y, test.exp, actual)
-		}
-	}
-}
-func TestLittleEndianByteAt(t *testing.T) {
-	tests := []struct {
-		x   string
-		y   int
-		exp byte
-	}{
-		{"00", 0, 0x00},
-		{"01", 1, 0x00},
-		{"00", 1, 0x00},
-		{"01", 0, 0x00},
-		{"0000000000000000000000000000000000000000000000000000000000102030", 0, 0x00},
-		{"0000000000000000000000000000000000000000000000000000000000102030", 1, 0x00},
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 31, 0x00},
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 32, 0x00},
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 0, 0xAB},
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 1, 0xCD},
-		{"00CDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff", 0, 0x00},
-		{"00CDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff", 1, 0xCD},
-		{"0000000000000000000000000000000000000000000000000000000000102030", 31, 0x30},
-		{"0000000000000000000000000000000000000000000000000000000000102030", 30, 0x20},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", 32, 0x0},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", 31, 0xFF},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", 0xFFFF, 0x0},
-	}
-	for _, test := range tests {
-		v := new(big.Int).SetBytes(common.Hex2Bytes(test.x))
-		actual := Byte(v, 32, test.y)
-		if actual != test.exp {
-			t.Fatalf("Expected  [%v] %v:th byte to be %v, was %v.", test.x, test.y, test.exp, actual)
-		}
-	}
-}