Optimize and minimize bound checks
Motivation: We should minimize and optimize bound checks as much as possible to get the most out of performance. Modifications: - Use bitwise operations to remove branching - Remove branches when possible Result: Better performance for various operations.
This commit is contained in:
Norman Maurer
parent
4403b1a7ea
commit
af9dc2c6a6
@ -232,11 +232,15 @@ public abstract class AbstractByteBuf extends ByteBuf {
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throw new IllegalArgumentException(String.format(
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"minWritableBytes: %d (expected: >= 0)", minWritableBytes));
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}
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if (minWritableBytes <= writableBytes()) {
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ensureWritable0(minWritableBytes);
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return this;
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}
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private void ensureWritable0(int minWritableBytes) {
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if (minWritableBytes <= writableBytes()) {
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return;
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}
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if (minWritableBytes > maxCapacity - writerIndex) {
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throw new IndexOutOfBoundsException(String.format(
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"writerIndex(%d) + minWritableBytes(%d) exceeds maxCapacity(%d): %s",
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@ -248,7 +252,6 @@ public abstract class AbstractByteBuf extends ByteBuf {
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// Adjust to the new capacity.
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capacity(newCapacity);
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return this;
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}
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@Override
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@ -543,21 +546,22 @@ public abstract class AbstractByteBuf extends ByteBuf {
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int nLong = length >>> 3;
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int nBytes = length & 7;
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for (int i = nLong; i > 0; i --) {
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setLong(index, 0);
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_setLong(index, 0);
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index += 8;
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}
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if (nBytes == 4) {
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setInt(index, 0);
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_setInt(index, 0);
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// Not need to update the index as we not will use it after this.
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} else if (nBytes < 4) {
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for (int i = nBytes; i > 0; i --) {
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setByte(index, (byte) 0);
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_setByte(index, (byte) 0);
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index ++;
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}
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} else {
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setInt(index, 0);
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_setInt(index, 0);
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index += 4;
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for (int i = nBytes - 4; i > 0; i --) {
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setByte(index, (byte) 0);
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_setByte(index, (byte) 0);
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index ++;
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}
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}
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@ -566,9 +570,9 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public byte readByte() {
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checkReadableBytes(1);
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checkReadableBytes0(1);
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int i = readerIndex;
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byte b = getByte(i);
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byte b = _getByte(i);
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readerIndex = i + 1;
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return b;
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}
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@ -585,7 +589,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public short readShort() {
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checkReadableBytes(2);
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checkReadableBytes0(2);
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short v = _getShort(readerIndex);
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readerIndex += 2;
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return v;
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@ -607,7 +611,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public int readUnsignedMedium() {
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checkReadableBytes(3);
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checkReadableBytes0(3);
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int v = _getUnsignedMedium(readerIndex);
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readerIndex += 3;
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return v;
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@ -615,7 +619,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public int readInt() {
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checkReadableBytes(4);
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checkReadableBytes0(4);
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int v = _getInt(readerIndex);
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readerIndex += 4;
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return v;
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@ -628,7 +632,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public long readLong() {
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checkReadableBytes(8);
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checkReadableBytes0(8);
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long v = _getLong(readerIndex);
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readerIndex += 8;
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return v;
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@ -751,7 +755,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public ByteBuf writeByte(int value) {
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ensureAccessible();
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ensureWritable(1);
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ensureWritable0(1);
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_setByte(writerIndex++, value);
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return this;
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}
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@ -759,7 +763,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public ByteBuf writeShort(int value) {
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ensureAccessible();
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ensureWritable(2);
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ensureWritable0(2);
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_setShort(writerIndex, value);
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writerIndex += 2;
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return this;
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@ -768,7 +772,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public ByteBuf writeMedium(int value) {
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ensureAccessible();
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ensureWritable(3);
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ensureWritable0(3);
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_setMedium(writerIndex, value);
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writerIndex += 3;
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return this;
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@ -777,7 +781,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public ByteBuf writeInt(int value) {
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ensureAccessible();
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ensureWritable(4);
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ensureWritable0(4);
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_setInt(writerIndex, value);
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writerIndex += 4;
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return this;
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@ -786,7 +790,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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@Override
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public ByteBuf writeLong(long value) {
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ensureAccessible();
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ensureWritable(8);
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ensureWritable0(8);
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_setLong(writerIndex, value);
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writerIndex += 8;
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return this;
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@ -891,25 +895,32 @@ public abstract class AbstractByteBuf extends ByteBuf {
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}
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ensureWritable(length);
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checkIndex(writerIndex, length);
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int wIndex = writerIndex;
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checkIndex(wIndex, length);
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int nLong = length >>> 3;
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int nBytes = length & 7;
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for (int i = nLong; i > 0; i --) {
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writeLong(0);
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_setLong(wIndex, 0);
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wIndex += 8;
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}
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if (nBytes == 4) {
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writeInt(0);
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_setInt(wIndex, 0);
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wIndex += 4;
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} else if (nBytes < 4) {
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for (int i = nBytes; i > 0; i --) {
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writeByte((byte) 0);
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_setByte(wIndex, (byte) 0);
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wIndex++;
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}
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} else {
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writeInt(0);
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_setInt(wIndex, 0);
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wIndex += 4;
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for (int i = nBytes - 4; i > 0; i --) {
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writeByte((byte) 0);
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_setByte(wIndex, (byte) 0);
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wIndex++;
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}
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}
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writerIndex = wIndex;
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return this;
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}
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@ -1117,19 +1128,12 @@ public abstract class AbstractByteBuf extends ByteBuf {
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}
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protected final void checkIndex(int index) {
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ensureAccessible();
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if (index < 0 || index >= capacity()) {
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throw new IndexOutOfBoundsException(String.format(
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"index: %d (expected: range(0, %d))", index, capacity()));
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}
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checkIndex(index, 1);
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}
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protected final void checkIndex(int index, int fieldLength) {
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ensureAccessible();
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if (fieldLength < 0) {
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throw new IllegalArgumentException("length: " + fieldLength + " (expected: >= 0)");
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}
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if (index < 0 || index > capacity() - fieldLength) {
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if (isInvalid(index, fieldLength, capacity())) {
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throw new IndexOutOfBoundsException(String.format(
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"index: %d, length: %d (expected: range(0, %d))", index, fieldLength, capacity()));
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}
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@ -1137,7 +1141,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
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protected final void checkSrcIndex(int index, int length, int srcIndex, int srcCapacity) {
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checkIndex(index, length);
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if (srcIndex < 0 || srcIndex > srcCapacity - length) {
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if (isInvalid(srcIndex, length, srcCapacity)) {
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throw new IndexOutOfBoundsException(String.format(
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"srcIndex: %d, length: %d (expected: range(0, %d))", srcIndex, length, srcCapacity));
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}
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@ -1145,22 +1149,30 @@ public abstract class AbstractByteBuf extends ByteBuf {
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protected final void checkDstIndex(int index, int length, int dstIndex, int dstCapacity) {
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checkIndex(index, length);
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if (dstIndex < 0 || dstIndex > dstCapacity - length) {
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if (isInvalid(dstIndex, length, dstCapacity)) {
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throw new IndexOutOfBoundsException(String.format(
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"dstIndex: %d, length: %d (expected: range(0, %d))", dstIndex, length, dstCapacity));
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}
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}
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private static boolean isInvalid(int index, int length, int capacity) {
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return (index | length | (index + length) | (capacity - (index + length))) < 0;
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}
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/**
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* Throws an {@link IndexOutOfBoundsException} if the current
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* {@linkplain #readableBytes() readable bytes} of this buffer is less
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* than the specified value.
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*/
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protected final void checkReadableBytes(int minimumReadableBytes) {
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ensureAccessible();
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if (minimumReadableBytes < 0) {
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throw new IllegalArgumentException("minimumReadableBytes: " + minimumReadableBytes + " (expected: >= 0)");
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}
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checkReadableBytes0(minimumReadableBytes);
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}
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private void checkReadableBytes0(int minimumReadableBytes) {
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ensureAccessible();
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if (readerIndex > writerIndex - minimumReadableBytes) {
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throw new IndexOutOfBoundsException(String.format(
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"readerIndex(%d) + length(%d) exceeds writerIndex(%d): %s",
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