Optimize Hpack and AsciiString hashcode and equals (#8902)
Motivation: While looking at hpack header-processing hotspots I noticed some low level too-big-to-inline methods which can be shrunk. Modifications: Reduce bytecode size and/or runtime operations used for the following methods: PlatformDependent0.equals(byte[], ...) PlatformDependent0.equalsConstantTime(byte[], ...) PlatformDependent0.hashCodeAscii(byte[],int,int) PlatformDependent.hashCodeAscii(CharSequence) Result: Existing benchmarks show decent improvement Before Benchmark (size) Mode Cnt Score Error Units HpackUtilBenchmark.newEquals SMALL thrpt 5 17200229.374 ± 1701239.198 ops/s HpackUtilBenchmark.newEquals MEDIUM thrpt 5 3386061.629 ± 72264.685 ops/s HpackUtilBenchmark.newEquals LARGE thrpt 5 507579.209 ± 65883.951 ops/s After Benchmark (size) Mode Cnt Score Error Units HpackUtilBenchmark.newEquals SMALL thrpt 5 29221527.058 ± 4805825.836 ops/s HpackUtilBenchmark.newEquals MEDIUM thrpt 5 6556251.645 ± 466115.199 ops/s HpackUtilBenchmark.newEquals LARGE thrpt 5 879828.889 ± 148136.641 ops/s Before Benchmark (size) Mode Cnt Score Error Units PlatformDepBench.unsafeBytesEqual 4 avgt 10 4.263 ± 0.110 ns/op PlatformDepBench.unsafeBytesEqual 10 avgt 10 5.206 ± 0.133 ns/op PlatformDepBench.unsafeBytesEqual 50 avgt 10 8.160 ± 0.320 ns/op PlatformDepBench.unsafeBytesEqual 100 avgt 10 13.810 ± 0.751 ns/op PlatformDepBench.unsafeBytesEqual 1000 avgt 10 89.077 ± 7.275 ns/op PlatformDepBench.unsafeBytesEqual 10000 avgt 10 773.940 ± 24.579 ns/op PlatformDepBench.unsafeBytesEqual 100000 avgt 10 7546.807 ± 110.395 ns/op After Benchmark (size) Mode Cnt Score Error Units PlatformDepBench.unsafeBytesEqual 4 avgt 10 3.337 ± 0.087 ns/op PlatformDepBench.unsafeBytesEqual 10 avgt 10 4.286 ± 0.194 ns/op PlatformDepBench.unsafeBytesEqual 50 avgt 10 7.817 ± 0.123 ns/op PlatformDepBench.unsafeBytesEqual 100 avgt 10 11.260 ± 0.412 ns/op PlatformDepBench.unsafeBytesEqual 1000 avgt 10 84.255 ± 2.596 ns/op PlatformDepBench.unsafeBytesEqual 10000 avgt 10 591.892 ± 5.136 ns/op PlatformDepBench.unsafeBytesEqual 100000 avgt 10 6978.859 ± 285.043 ns/op
This commit is contained in:
Nick Hill
Norman Maurer
parent
7e76d02fe7
commit
a258cd6f42
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@ -682,83 +682,43 @@ public final class PlatformDependent {
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* The resulting hash code will be case insensitive.
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*/
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public static int hashCodeAscii(CharSequence bytes) {
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final int length = bytes.length();
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final int remainingBytes = length & 7;
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int hash = HASH_CODE_ASCII_SEED;
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final int remainingBytes = bytes.length() & 7;
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// Benchmarking shows that by just naively looping for inputs 8~31 bytes long we incur a relatively large
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// performance penalty (only achieve about 60% performance of loop which iterates over each char). So because
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// of this we take special provisions to unroll the looping for these conditions.
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switch (bytes.length()) {
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case 31:
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case 30:
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case 29:
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case 28:
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case 27:
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case 26:
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case 25:
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case 24:
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hash = hashCodeAsciiCompute(bytes, bytes.length() - 24,
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hashCodeAsciiCompute(bytes, bytes.length() - 16,
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hashCodeAsciiCompute(bytes, bytes.length() - 8, hash)));
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break;
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case 23:
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case 22:
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case 21:
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case 20:
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case 19:
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case 18:
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case 17:
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case 16:
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hash = hashCodeAsciiCompute(bytes, bytes.length() - 16,
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hashCodeAsciiCompute(bytes, bytes.length() - 8, hash));
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break;
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case 15:
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case 14:
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case 13:
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case 12:
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case 11:
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case 10:
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case 9:
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case 8:
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hash = hashCodeAsciiCompute(bytes, bytes.length() - 8, hash);
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break;
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case 7:
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case 6:
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case 5:
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case 4:
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case 3:
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case 2:
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case 1:
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case 0:
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break;
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default:
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for (int i = bytes.length() - 8; i >= remainingBytes; i -= 8) {
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hash = hashCodeAsciiCompute(bytes, i, hash);
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if (length >= 32) {
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for (int i = length - 8; i >= remainingBytes; i -= 8) {
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hash = hashCodeAsciiCompute(bytes, i, hash);
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}
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} else if (length >= 8) {
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hash = hashCodeAsciiCompute(bytes, length - 8, hash);
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if (length >= 16) {
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hash = hashCodeAsciiCompute(bytes, length - 16, hash);
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if (length >= 24) {
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hash = hashCodeAsciiCompute(bytes, length - 24, hash);
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}
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break;
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}
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}
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switch(remainingBytes) {
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case 7:
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return ((hash * HASH_CODE_C1 + hashCodeAsciiSanitizeByte(bytes.charAt(0)))
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* HASH_CODE_C2 + hashCodeAsciiSanitizeShort(bytes, 1))
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* HASH_CODE_C1 + hashCodeAsciiSanitizeInt(bytes, 3);
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case 6:
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return (hash * HASH_CODE_C1 + hashCodeAsciiSanitizeShort(bytes, 0))
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* HASH_CODE_C2 + hashCodeAsciiSanitizeInt(bytes, 2);
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case 5:
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return (hash * HASH_CODE_C1 + hashCodeAsciiSanitizeByte(bytes.charAt(0)))
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* HASH_CODE_C2 + hashCodeAsciiSanitizeInt(bytes, 1);
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case 4:
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return hash * HASH_CODE_C1 + hashCodeAsciiSanitizeInt(bytes, 0);
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case 3:
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return (hash * HASH_CODE_C1 + hashCodeAsciiSanitizeByte(bytes.charAt(0)))
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* HASH_CODE_C2 + hashCodeAsciiSanitizeShort(bytes, 1);
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case 2:
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return hash * HASH_CODE_C1 + hashCodeAsciiSanitizeShort(bytes, 0);
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case 1:
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return hash * HASH_CODE_C1 + hashCodeAsciiSanitizeByte(bytes.charAt(0));
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default:
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return hash;
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if (remainingBytes == 0) {
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return hash;
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}
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int offset = 0;
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if (remainingBytes != 2 & remainingBytes != 4 & remainingBytes != 6) { // 1, 3, 5, 7
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hash = hash * HASH_CODE_C1 + hashCodeAsciiSanitizeByte(bytes.charAt(0));
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offset = 1;
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}
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if (remainingBytes != 1 & remainingBytes != 4 & remainingBytes != 5) { // 2, 3, 6, 7
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hash = hash * (offset == 0 ? HASH_CODE_C1 : HASH_CODE_C2)
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+ hashCodeAsciiSanitize(hashCodeAsciiSanitizeShort(bytes, offset));
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offset += 2;
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}
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if (remainingBytes >= 4) { // 4, 5, 6, 7
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return hash * ((offset == 0 | offset == 3) ? HASH_CODE_C1 : HASH_CODE_C2)
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+ hashCodeAsciiSanitizeInt(bytes, offset);
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}
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return hash;
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}
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private static final class Mpsc {
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@ -569,72 +569,57 @@ final class PlatformDependent0 {
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}
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static boolean equals(byte[] bytes1, int startPos1, byte[] bytes2, int startPos2, int length) {
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if (length <= 0) {
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return true;
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}
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final long baseOffset1 = BYTE_ARRAY_BASE_OFFSET + startPos1;
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final long baseOffset2 = BYTE_ARRAY_BASE_OFFSET + startPos2;
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int remainingBytes = length & 7;
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final long end = baseOffset1 + remainingBytes;
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for (long i = baseOffset1 - 8 + length, j = baseOffset2 - 8 + length; i >= end; i -= 8, j -= 8) {
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if (UNSAFE.getLong(bytes1, i) != UNSAFE.getLong(bytes2, j)) {
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return false;
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final long baseOffset1 = BYTE_ARRAY_BASE_OFFSET + startPos1;
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final long diff = startPos2 - startPos1;
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if (length >= 8) {
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final long end = baseOffset1 + remainingBytes;
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for (long i = baseOffset1 - 8 + length; i >= end; i -= 8) {
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if (UNSAFE.getLong(bytes1, i) != UNSAFE.getLong(bytes2, i + diff)) {
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return false;
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}
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}
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}
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if (remainingBytes >= 4) {
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remainingBytes -= 4;
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if (UNSAFE.getInt(bytes1, baseOffset1 + remainingBytes) !=
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UNSAFE.getInt(bytes2, baseOffset2 + remainingBytes)) {
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long pos = baseOffset1 + remainingBytes;
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if (UNSAFE.getInt(bytes1, pos) != UNSAFE.getInt(bytes2, pos + diff)) {
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return false;
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}
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}
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final long baseOffset2 = baseOffset1 + diff;
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if (remainingBytes >= 2) {
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return UNSAFE.getChar(bytes1, baseOffset1) == UNSAFE.getChar(bytes2, baseOffset2) &&
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(remainingBytes == 2 || bytes1[startPos1 + 2] == bytes2[startPos2 + 2]);
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(remainingBytes == 2 ||
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UNSAFE.getByte(bytes1, baseOffset1 + 2) == UNSAFE.getByte(bytes2, baseOffset2 + 2));
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}
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return bytes1[startPos1] == bytes2[startPos2];
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return remainingBytes == 0 ||
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UNSAFE.getByte(bytes1, baseOffset1) == UNSAFE.getByte(bytes2, baseOffset2);
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}
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static int equalsConstantTime(byte[] bytes1, int startPos1, byte[] bytes2, int startPos2, int length) {
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long result = 0;
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long remainingBytes = length & 7;
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final long baseOffset1 = BYTE_ARRAY_BASE_OFFSET + startPos1;
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final long baseOffset2 = BYTE_ARRAY_BASE_OFFSET + startPos2;
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final int remainingBytes = length & 7;
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final long end = baseOffset1 + remainingBytes;
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for (long i = baseOffset1 - 8 + length, j = baseOffset2 - 8 + length; i >= end; i -= 8, j -= 8) {
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result |= UNSAFE.getLong(bytes1, i) ^ UNSAFE.getLong(bytes2, j);
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final long diff = startPos2 - startPos1;
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for (long i = baseOffset1 - 8 + length; i >= end; i -= 8) {
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result |= UNSAFE.getLong(bytes1, i) ^ UNSAFE.getLong(bytes2, i + diff);
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}
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switch (remainingBytes) {
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case 7:
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return ConstantTimeUtils.equalsConstantTime(result |
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(UNSAFE.getInt(bytes1, baseOffset1 + 3) ^ UNSAFE.getInt(bytes2, baseOffset2 + 3)) |
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(UNSAFE.getChar(bytes1, baseOffset1 + 1) ^ UNSAFE.getChar(bytes2, baseOffset2 + 1)) |
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(UNSAFE.getByte(bytes1, baseOffset1) ^ UNSAFE.getByte(bytes2, baseOffset2)), 0);
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case 6:
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return ConstantTimeUtils.equalsConstantTime(result |
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(UNSAFE.getInt(bytes1, baseOffset1 + 2) ^ UNSAFE.getInt(bytes2, baseOffset2 + 2)) |
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(UNSAFE.getChar(bytes1, baseOffset1) ^ UNSAFE.getChar(bytes2, baseOffset2)), 0);
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case 5:
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return ConstantTimeUtils.equalsConstantTime(result |
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(UNSAFE.getInt(bytes1, baseOffset1 + 1) ^ UNSAFE.getInt(bytes2, baseOffset2 + 1)) |
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(UNSAFE.getByte(bytes1, baseOffset1) ^ UNSAFE.getByte(bytes2, baseOffset2)), 0);
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case 4:
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return ConstantTimeUtils.equalsConstantTime(result |
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(UNSAFE.getInt(bytes1, baseOffset1) ^ UNSAFE.getInt(bytes2, baseOffset2)), 0);
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case 3:
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return ConstantTimeUtils.equalsConstantTime(result |
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(UNSAFE.getChar(bytes1, baseOffset1 + 1) ^ UNSAFE.getChar(bytes2, baseOffset2 + 1)) |
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(UNSAFE.getByte(bytes1, baseOffset1) ^ UNSAFE.getByte(bytes2, baseOffset2)), 0);
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case 2:
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return ConstantTimeUtils.equalsConstantTime(result |
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(UNSAFE.getChar(bytes1, baseOffset1) ^ UNSAFE.getChar(bytes2, baseOffset2)), 0);
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case 1:
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return ConstantTimeUtils.equalsConstantTime(result |
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(UNSAFE.getByte(bytes1, baseOffset1) ^ UNSAFE.getByte(bytes2, baseOffset2)), 0);
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default:
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return ConstantTimeUtils.equalsConstantTime(result, 0);
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if (remainingBytes >= 4) {
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result |= UNSAFE.getInt(bytes1, baseOffset1) ^ UNSAFE.getInt(bytes2, baseOffset1 + diff);
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remainingBytes -= 4;
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}
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if (remainingBytes >= 2) {
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long pos = end - remainingBytes;
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result |= UNSAFE.getChar(bytes1, pos) ^ UNSAFE.getChar(bytes2, pos + diff);
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remainingBytes -= 2;
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}
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if (remainingBytes == 1) {
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long pos = end - 1;
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result |= UNSAFE.getByte(bytes1, pos) ^ UNSAFE.getByte(bytes2, pos + diff);
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}
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return ConstantTimeUtils.equalsConstantTime(result, 0);
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}
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static boolean isZero(byte[] bytes, int startPos, int length) {
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@ -665,35 +650,30 @@ final class PlatformDependent0 {
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static int hashCodeAscii(byte[] bytes, int startPos, int length) {
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int hash = HASH_CODE_ASCII_SEED;
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final long baseOffset = BYTE_ARRAY_BASE_OFFSET + startPos;
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long baseOffset = BYTE_ARRAY_BASE_OFFSET + startPos;
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final int remainingBytes = length & 7;
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final long end = baseOffset + remainingBytes;
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for (long i = baseOffset - 8 + length; i >= end; i -= 8) {
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hash = hashCodeAsciiCompute(UNSAFE.getLong(bytes, i), hash);
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}
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switch(remainingBytes) {
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case 7:
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return ((hash * HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getByte(bytes, baseOffset)))
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* HASH_CODE_C2 + hashCodeAsciiSanitize(UNSAFE.getShort(bytes, baseOffset + 1)))
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* HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getInt(bytes, baseOffset + 3));
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case 6:
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return (hash * HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getShort(bytes, baseOffset)))
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* HASH_CODE_C2 + hashCodeAsciiSanitize(UNSAFE.getInt(bytes, baseOffset + 2));
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case 5:
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return (hash * HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getByte(bytes, baseOffset)))
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* HASH_CODE_C2 + hashCodeAsciiSanitize(UNSAFE.getInt(bytes, baseOffset + 1));
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case 4:
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return hash * HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getInt(bytes, baseOffset));
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case 3:
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return (hash * HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getByte(bytes, baseOffset)))
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* HASH_CODE_C2 + hashCodeAsciiSanitize(UNSAFE.getShort(bytes, baseOffset + 1));
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case 2:
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return hash * HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getShort(bytes, baseOffset));
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case 1:
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return hash * HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getByte(bytes, baseOffset));
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default:
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if (remainingBytes == 0) {
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return hash;
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}
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int hcConst = HASH_CODE_C1;
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if (remainingBytes != 2 & remainingBytes != 4 & remainingBytes != 6) { // 1, 3, 5, 7
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hash = hash * HASH_CODE_C1 + hashCodeAsciiSanitize(UNSAFE.getByte(bytes, baseOffset));
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hcConst = HASH_CODE_C2;
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baseOffset++;
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}
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if (remainingBytes != 1 & remainingBytes != 4 & remainingBytes != 5) { // 2, 3, 6, 7
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hash = hash * hcConst + hashCodeAsciiSanitize(UNSAFE.getShort(bytes, baseOffset));
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hcConst = hcConst == HASH_CODE_C1 ? HASH_CODE_C2 : HASH_CODE_C1;
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baseOffset += 2;
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}
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if (remainingBytes >= 4) { // 4, 5, 6, 7
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return hash * hcConst + hashCodeAsciiSanitize(UNSAFE.getInt(bytes, baseOffset));
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}
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return hash;
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}
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static int hashCodeAsciiCompute(long value, int hash) {
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