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Make DataWord immutable #884

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Make DataWord immutable #884

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1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@ logs
test_db*
testnetSampleDb
sampleDB*
out

# Mac
.DS_Store
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3 changes: 1 addition & 2 deletions ethereumj-core/src/main/java/org/ethereum/config/CommonConfig.java
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Expand Up @@ -208,8 +208,7 @@ public Source<byte[], ProgramPrecompile> precompileSource() {
new Serializer<byte[], byte[]>() {
public byte[] serialize(byte[] object) {
DataWord ret = new DataWord(object);
ret.add(new DataWord(1));
return ret.getLast20Bytes();
return ret.add(new DataWord(1)).getLast20Bytes();
}
public byte[] deserialize(byte[] stream) {
throw new RuntimeException("Shouldn't be called");
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2 changes: 1 addition & 1 deletion ethereumj-core/src/main/java/org/ethereum/config/blockchain/AbstractConfig.java
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Expand Up @@ -142,7 +142,7 @@ public DataWord getCallGas(OpCode op, DataWord requestedGas, DataWord availableG
if (requestedGas.compareTo(availableGas) > 0) {
throw Program.Exception.notEnoughOpGas(op, requestedGas, availableGas);
}
return requestedGas.clone();
return requestedGas;
}

@Override
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6 changes: 1 addition & 5 deletions ethereumj-core/src/main/java/org/ethereum/util/Utils.java
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Expand Up @@ -230,11 +230,7 @@ public static List<ByteArrayWrapper> dumpKeys(DbSource<byte[]> ds) {
}

public static DataWord allButOne64th(DataWord dw) {
DataWord ret = dw.clone();
DataWord d = dw.clone();
d.div(DIVISOR);
ret.sub(d);
return ret;
return dw.sub(dw.div(DIVISOR));
}

/**
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168 changes: 81 additions & 87 deletions ethereumj-core/src/main/java/org/ethereum/vm/DataWord.java
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Expand Up @@ -31,6 +31,7 @@
/**
* DataWord is the 32-byte array representation of a 256-bit number
* Calculations can be done on this word with other DataWords
* The data byte array is immutable
*
* @author Roman Mandeleil
* @since 01.06.2014
Expand All @@ -40,12 +41,12 @@ public class DataWord implements Comparable<DataWord> {
/* Maximum value of the DataWord */
public static final BigInteger _2_256 = BigInteger.valueOf(2).pow(256);
public static final BigInteger MAX_VALUE = _2_256.subtract(BigInteger.ONE);
public static final DataWord ZERO = new DataWord(new byte[32]); // don't push it in to the stack
public static final DataWord ZERO_EMPTY_ARRAY = new DataWord(new byte[0]); // don't push it in to the stack
public static final DataWord ZERO = new DataWord();

private byte[] data = new byte[32];
private final byte[] data;

public DataWord() {
this.data = new byte[32];
}

public DataWord(int num) {
Expand Down Expand Up @@ -73,18 +74,20 @@ public DataWord(ByteArrayWrapper wrappedData){
}

public DataWord(byte[] data) {
if (data == null)
if (data == null) {
this.data = ByteUtil.EMPTY_BYTE_ARRAY;
else if (data.length == 32)
this.data = data;
else if (data.length <= 32)
} else if (data.length == 32) {
this.data = Arrays.clone(data);
} else if (data.length <= 32) {
this.data = new byte[32];
System.arraycopy(data, 0, this.data, 32 - data.length, data.length);
}
else
throw new RuntimeException("Data word can't exceed 32 bytes: " + data);
}

public byte[] getData() {
return data;
return copyData();
}

public byte[] getNoLeadZeroesData() {
Expand Down Expand Up @@ -182,158 +185,144 @@ public boolean isNegative() {
return result == 0x80;
}

public DataWord and(DataWord w2) {
private byte[] copyData() {
return Arrays.clone(data);
}

for (int i = 0; i < this.data.length; ++i) {
this.data[i] &= w2.data[i];
public DataWord and(DataWord w2) {
byte[] data = copyData();
for (int i = 0; i < data.length; ++i) {
data[i] &= w2.data[i];
}
return this;
return new DataWord(data);
}

public DataWord or(DataWord w2) {

for (int i = 0; i < this.data.length; ++i) {
this.data[i] |= w2.data[i];
byte[] data = copyData();
for (int i = 0; i < data.length; ++i) {
data[i] |= w2.data[i];
}
return this;
return new DataWord(data);
}

public DataWord xor(DataWord w2) {

for (int i = 0; i < this.data.length; ++i) {
this.data[i] ^= w2.data[i];
byte[] data = copyData();
for (int i = 0; i < data.length; ++i) {
data[i] ^= w2.data[i];
}
return this;
return new DataWord(data);
}

public void negate() {

if (this.isZero()) return;
public DataWord negate() {
if (this.isZero()) {
return this;
}

for (int i = 0; i < this.data.length; ++i) {
this.data[i] = (byte) ~this.data[i];
byte[] data = copyData();
for (int i = 0; i < data.length; ++i) {
data[i] = (byte) ~ data[i];
}

for (int i = this.data.length - 1; i >= 0; --i) {
this.data[i] = (byte) (1 + this.data[i] & 0xFF);
if (this.data[i] != 0) break;
for (int i = data.length - 1; i >= 0; --i) {
data[i] = (byte) (1 + data[i] & 0xFF);
if (data[i] != 0) {
break;
}
}
return new DataWord(data);
}

public void bnot() {
public DataWord bnot() {
if (this.isZero()) {
this.data = ByteUtil.copyToArray(MAX_VALUE);
return;
return new DataWord(ByteUtil.copyToArray(MAX_VALUE));
}
this.data = ByteUtil.copyToArray(MAX_VALUE.subtract(this.value()));
return new DataWord(ByteUtil.copyToArray(MAX_VALUE.subtract(this.value())));
}

// By : Holger
// From : http://stackoverflow.com/a/24023466/459349
public void add(DataWord word) {
public DataWord add(DataWord word) {
byte[] result = new byte[32];
for (int i = 31, overflow = 0; i >= 0; i--) {
int v = (this.data[i] & 0xff) + (word.data[i] & 0xff) + overflow;
result[i] = (byte) v;
overflow = v >>> 8;
}
this.data = result;
}

// old add-method with BigInteger quick hack
public void add2(DataWord word) {
BigInteger result = value().add(word.value());
this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(result);
}

// TODO: mul can be done in more efficient way
// TODO: with shift left shift right trick
// TODO without BigInteger quick hack
public void mul(DataWord word) {
public DataWord mul(DataWord word) {
BigInteger result = value().multiply(word.value());
this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(ByteUtil.copyToArray(result.and(MAX_VALUE)));
}

// TODO: improve with no BigInteger
public void div(DataWord word) {

public DataWord div(DataWord word) {
if (word.isZero()) {
this.and(ZERO);
return;
return ZERO;
}

BigInteger result = value().divide(word.value());
this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(ByteUtil.copyToArray(result.and(MAX_VALUE)));
}

// TODO: improve with no BigInteger
public void sDiv(DataWord word) {

public DataWord sDiv(DataWord word) {
if (word.isZero()) {
this.and(ZERO);
return;
return ZERO;
}

BigInteger result = sValue().divide(word.sValue());
this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(ByteUtil.copyToArray(result.and(MAX_VALUE)));
}

// TODO: improve with no BigInteger
public void sub(DataWord word) {
public DataWord sub(DataWord word) {
BigInteger result = value().subtract(word.value());
this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
byte[] data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(data);
}

// TODO: improve with no BigInteger
public void exp(DataWord word) {
public DataWord exp(DataWord word) {
BigInteger result = value().modPow(word.value(), _2_256);
this.data = ByteUtil.copyToArray(result);
return new DataWord(ByteUtil.copyToArray(result));
}

// TODO: improve with no BigInteger
public void mod(DataWord word) {

public DataWord mod(DataWord word) {
if (word.isZero()) {
this.and(ZERO);
return;
return ZERO;
}

BigInteger result = value().mod(word.value());
this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(ByteUtil.copyToArray(result.and(MAX_VALUE)));
}

public void sMod(DataWord word) {

public DataWord sMod(DataWord word) {
if (word.isZero()) {
this.and(ZERO);
return;
return ZERO;
}

BigInteger result = sValue().abs().mod(word.sValue().abs());
result = (sValue().signum() == -1) ? result.negate() : result;

this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(ByteUtil.copyToArray(result.and(MAX_VALUE)));
}

public void addmod(DataWord word1, DataWord word2) {
public DataWord addmod(DataWord word1, DataWord word2) {
if (word2.isZero()) {
this.data = new byte[32];
return;
return ZERO;
}

BigInteger result = value().add(word1.value()).mod(word2.value());
this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(ByteUtil.copyToArray(result.and(MAX_VALUE)));
}

public void mulmod(DataWord word1, DataWord word2) {

public DataWord mulmod(DataWord word1, DataWord word2) {
if (this.isZero() || word1.isZero() || word2.isZero()) {
this.data = new byte[32];
return;
return ZERO;
}

BigInteger result = value().multiply(word1.value()).mod(word2.value());
this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
return new DataWord(ByteUtil.copyToArray(result.and(MAX_VALUE)));
}

@JsonValue
Expand All @@ -358,10 +347,6 @@ public String shortHex() {
return "0x" + hexValue.replaceFirst("^0+(?!$)", "");
}

public DataWord clone() {
return new DataWord(Arrays.clone(data));
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
Expand All @@ -388,13 +373,15 @@ public int compareTo(DataWord o) {
return (int) Math.signum(result);
}

public void signExtend(byte k) {
public DataWord signExtend(byte k) {
if (0 > k || k > 31)
throw new IndexOutOfBoundsException();
byte mask = this.sValue().testBit((k * 8) + 7) ? (byte) 0xff : 0;
byte[] data = copyData();
for (int i = 31; i > k; i--) {
this.data[31 - i] = mask;
data[31 - i] = mask;
}
return new DataWord(data);
}

public int bytesOccupied() {
Expand All @@ -410,4 +397,11 @@ public boolean isHex(String hex) {
public String asString(){
return new String(getNoLeadZeroesData());
}

public DataWord withByte(byte b, int i) {
byte[] data = copyData();
data[i] = b;
return new DataWord(data);
}

}
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