core/vm, common/math: Add doc about Byte, fix format

This commit is contained in:
Martin Holst Swende 2017-06-08 23:16:05 +02:00
parent 1496b3aff6
commit ac9865791a
3 changed files with 20 additions and 16 deletions

View File

@ -131,7 +131,7 @@ func PaddedBigBytes(bigint *big.Int, n int) []byte {
}
// bigEndianByteAt returns the byte at position n,
// if bigint is considered big-endian.
// in Big-Endian encoding
// So n==0 returns the least significant byte
func bigEndianByteAt(bigint *big.Int, n int) byte {
words := bigint.Bits()
@ -148,9 +148,9 @@ func bigEndianByteAt(bigint *big.Int, n int) byte {
}
// Byte returns the byte at position n,
// if bigint is considered little-endian with the supplied padlength.
// n==0 returns the most significant byte
// bigint '5', padlength 32, n=31 => 5
// 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)

View File

@ -141,6 +141,7 @@ func BenchmarkPaddedBigBytesLargePadding(b *testing.B) {
PaddedBigBytes(bigint, 200)
}
}
func BenchmarkPaddedBigBytesSmallPadding(b *testing.B) {
bigint := MustParseBig256("0x18F8F8F1000111000110011100222004330052300000000000000000FEFCF3CC")
for i := 0; i < b.N; i++ {
@ -154,18 +155,21 @@ func BenchmarkPaddedBigBytesSmallOnePadding(b *testing.B) {
PaddedBigBytes(bigint, 32)
}
}
func BenchmarkByteAtBrandNew(b *testing.B) {
bigint := MustParseBig256("0x18F8F8F1000111000110011100222004330052300000000000000000FEFCF3CC")
for i := 0; i < b.N; i++ {
bigEndianByteAt(bigint, 15)
}
}
func BenchmarkByteAt(b *testing.B) {
bigint := MustParseBig256("0x18F8F8F1000111000110011100222004330052300000000000000000FEFCF3CC")
for i := 0; i < b.N; i++ {
bigEndianByteAt(bigint, 15)
}
}
func BenchmarkByteAtOld(b *testing.B) {
bigint := MustParseBig256("0x18F8F8F1000111000110011100222004330052300000000000000000FEFCF3CC")
@ -207,21 +211,22 @@ func TestU256(t *testing.T) {
}
}
}
func TestLittleEndianByteAt(t *testing.T) {
func TestBigEndianByteAt(t *testing.T) {
tests := []struct {
x string
y int
exp byte
}{
{"0", 0, 0x00},
{"1", 1, 0x00},
{"0", 1, 0x00},
//{"1", 0, 0x01},
{"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))
@ -232,17 +237,16 @@ func TestLittleEndianByteAt(t *testing.T) {
}
}
func TestBigEndianByteAt(t *testing.T) {
func TestLittleEndianByteAt(t *testing.T) {
tests := []struct {
x string
y int
exp byte
}{
{"0", 0, 0x00},
{"1", 1, 0x00},
{"0", 1, 0x00},
{"1", 0, 0x00},
{"00", 0, 0x00},
{"01", 1, 0x00},
{"00", 1, 0x00},
{"01", 0, 0x00},
{"0000000000000000000000000000000000000000000000000000000000102030", 0, 0x00},
{"0000000000000000000000000000000000000000000000000000000000102030", 1, 0x00},
{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 31, 0x00},
@ -266,6 +270,7 @@ func TestBigEndianByteAt(t *testing.T) {
}
}
func TestS256(t *testing.T) {
tests := []struct{ x, y *big.Int }{
{x: big.NewInt(0), y: big.NewInt(0)},

View File

@ -9,7 +9,6 @@ import (
)
func TestByteOp(t *testing.T) {
var (
env = NewEVM(Context{}, nil, params.TestChainConfig, Config{EnableJit: false, ForceJit: false})
stack = newstack()