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Use SWAR technique for more efficient parsing and serialization on JV…
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…Ms (#866) (#876)
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@plokhotnyuk
plokhotnyuk committed Mar 28, 2022
1 parent 44949d8 commit b1cec24
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30 changes: 30 additions & 0 deletions ...la-core/jvm/src/main/java/com/github/plokhotnyuk/jsoniter_scala/core/ByteArrayAccess.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,30 @@
package com.github.plokhotnyuk.jsoniter_scala.core;

import java.lang.invoke.MethodHandles;
import java.lang.invoke.VarHandle;
import java.nio.ByteOrder;

class ByteArrayAccess { // FIXME: Use Java wrapper as w/a for missing support of @PolymorphicSignature methods in Scala 3, see: https://github.com/lampepfl/dotty/issues/11332
private static final VarHandle VH_LONG =
MethodHandles.byteArrayViewVarHandle(long[].class, ByteOrder.LITTLE_ENDIAN);
private static final VarHandle VH_INT =
MethodHandles.byteArrayViewVarHandle(int[].class, ByteOrder.LITTLE_ENDIAN);
private static final VarHandle VH_SHORT =
MethodHandles.byteArrayViewVarHandle(short[].class, ByteOrder.LITTLE_ENDIAN);

static void setLong(byte[] buf, int pos, long value) {
VH_LONG.set(buf, pos, value);
}

static long getLong(byte[] buf, int pos) {
return (long) VH_LONG.get(buf, pos);
}

static void setInt(byte[] buf, int pos, int value) {
VH_INT.set(buf, pos, value);
}

static void setShort(byte[] buf, int pos, short value) {
VH_SHORT.set(buf, pos, value);
}
}
82 changes: 66 additions & 16 deletions ...scala-core/jvm/src/main/scala/com/github/plokhotnyuk/jsoniter_scala/core/JsonReader.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -1272,6 +1272,25 @@ final class JsonReader private[jsoniter_scala](
else {
var pos = head
var buf = this.buf
var bs = 0L
while ((pos + 7 < tail || {
pos = loadMore(pos)
buf = this.buf
pos + 7 < tail
}) && {
bs = ByteArrayAccess.getLong(buf, pos) // Use a trick of fast 8 digit checking from: https://github.com/simdjson/simdjson/blob/7e1893db428936e13457ba0e9a5aac0cdfb7bc15/include/simdjson/generic/numberparsing.h#L344
(bs & 0xF0F0F0F0F0F0F0F0L) == 0x3030303030303030L &&
((bs + 0x0606060606060606L) & 0xF0F0F0F0F0F0F0F0L) == 0x3030303030303030L
}) {
if (x < -92233720368L || { // Use a trick of fast 8 digit to int conversion from: http://govnokod.ru/13461#comment189156
bs = (bs & 0x0F0F0F0F0F0F0F0FL) * 2561 >> 8
bs = (bs & 0x00FF00FF00FF00FFL) * 6553601 >> 16
bs = (bs & 0x0000FFFF0000FFFFL) * 42949672960001L >> 32
x = x * 100000000 - bs
x > 0
}) longOverflowError(pos + 2)
pos += 8
}
while ((pos < tail || {
pos = loadMore(pos)
buf = this.buf
Expand Down Expand Up @@ -1617,6 +1636,15 @@ final class JsonReader private[jsoniter_scala](
else oldMark
mark = newMark
try {
while ((pos + 7 < tail || {
pos = loadMore(pos)
buf = this.buf
pos + 7 < tail
}) && {
val bs = ByteArrayAccess.getLong(buf, pos) // Use a trick of fast 8 digit checking from: https://github.com/simdjson/simdjson/blob/7e1893db428936e13457ba0e9a5aac0cdfb7bc15/include/simdjson/generic/numberparsing.h#L344
(bs & 0xF0F0F0F0F0F0F0F0L) == 0x3030303030303030L &&
((bs + 0x0606060606060606L) & 0xF0F0F0F0F0F0F0F0L) == 0x3030303030303030L
}) pos += 8
while ((pos < tail || {
pos = loadMore(pos)
buf = this.buf
Expand Down Expand Up @@ -1666,6 +1694,17 @@ final class JsonReader private[jsoniter_scala](
}) leadingZeroError(pos - 1)
} else {
digits -= pos
while ((pos + 7 < tail || {
digits += pos
pos = loadMore(pos)
digits -= pos
buf = this.buf
pos + 7 < tail
}) && {
val bs = ByteArrayAccess.getLong(buf, pos) // Use a trick of fast 8 digit checking from: https://github.com/simdjson/simdjson/blob/7e1893db428936e13457ba0e9a5aac0cdfb7bc15/include/simdjson/generic/numberparsing.h#L344
(bs & 0xF0F0F0F0F0F0F0F0L) == 0x3030303030303030L &&
((bs + 0x0606060606060606L) & 0xF0F0F0F0F0F0F0F0L) == 0x3030303030303030L
}) pos += 8
while ((pos < tail || {
digits += pos
pos = loadMore(pos)
Expand All @@ -1683,6 +1722,17 @@ final class JsonReader private[jsoniter_scala](
if (b == '.') {
pos += 1
fracLen -= pos
while ((pos + 7 < tail || {
fracLen += pos
pos = loadMore(pos)
fracLen -= pos
buf = this.buf
pos + 7 < tail
}) && {
val bs = ByteArrayAccess.getLong(buf, pos) // Use a trick of fast 8 digit checking from: https://github.com/simdjson/simdjson/blob/7e1893db428936e13457ba0e9a5aac0cdfb7bc15/include/simdjson/generic/numberparsing.h#L344
(bs & 0xF0F0F0F0F0F0F0F0L) == 0x3030303030303030L &&
((bs + 0x0606060606060606L) & 0xF0F0F0F0F0F0F0F0L) == 0x3030303030303030L
}) pos += 8
while ((pos < tail || {
fracLen += pos
pos = loadMore(pos)
Expand Down Expand Up @@ -1789,16 +1839,17 @@ final class JsonReader private[jsoniter_scala](
x1 = x1 * 10 + (buf(pos) - '0')
pos += 1
}
var x2 =
(buf(pos) * 10 + buf(pos + 1)) * 10000000000000000L +
((buf(pos + 2) * 10 + buf(pos + 3)) * 1000000 +
(buf(pos + 4) * 10 + buf(pos + 5)) * 10000 +
(buf(pos + 6) * 10 + buf(pos + 7)) * 100 +
(buf(pos + 8) * 10 + buf(pos + 9))) * 100000000L +
((buf(pos + 10) * 10 + buf(pos + 11)) * 1000000 +
(buf(pos + 12) * 10 + buf(pos + 13)) * 10000 +
(buf(pos + 14) * 10 + buf(pos + 15)) * 100 +
buf(pos + 16) * 10 + buf(pos + 17)) - 5333333333333333328L // 5333333333333333328L == '0' * 111111111111111111L
var bs = ByteArrayAccess.getLong(buf, pos) // Use a trick of fast 8 digit to int conversion from: http://govnokod.ru/13461#comment189156
bs = (bs & 0x0F0F0F0F0F0F0F0FL) * 2561 >> 8
bs = (bs & 0x00FF00FF00FF00FFL) * 6553601 >> 16
bs = (bs & 0x0000FFFF0000FFFFL) * 42949672960001L >> 32
var x2 = (bs * 10 + (buf(pos + 8) - '0')) * 1000000000 + {
bs = ByteArrayAccess.getLong(buf, pos + 9) // Use a trick of fast 8 digit to int conversion from: http://govnokod.ru/13461#comment189156
bs = (bs & 0x0F0F0F0F0F0F0F0FL) * 2561 >> 8
bs = (bs & 0x00FF00FF00FF00FFL) * 6553601 >> 16
bs = (bs & 0x0000FFFF0000FFFFL) * 42949672960001L >> 32
bs * 10 + (buf(pos + 17) - '0')
}
if (isNeg) {
x1 = -x1
x2 = -x2
Expand All @@ -1823,12 +1874,11 @@ final class JsonReader private[jsoniter_scala](
val magWords = new Array[Int](numWords)
magWords(lastWord) = x.toInt
while (pos < limit) {
x =
(buf(pos) * 10 + buf(pos + 1)) * 10000000L +
((buf(pos + 2) * 10 + buf(pos + 3)) * 100000 +
(buf(pos + 4) * 10 + buf(pos + 5)) * 1000 +
(buf(pos + 6) * 10 + buf(pos + 7)) * 10 +
buf(pos + 8)) - 5333333328L // 5333333328L == '0' * 111111111L
x = ByteArrayAccess.getLong(buf, pos) // Use a trick of fast 8 digit to int conversion from: http://govnokod.ru/13461#comment189156
x = (x & 0x0F0F0F0F0F0F0F0FL) * 2561 >> 8
x = (x & 0x00FF00FF00FF00FFL) * 6553601 >> 16
x = (x & 0x0000FFFF0000FFFFL) * 42949672960001L >> 32
x = x * 10 + (buf(pos + 8) - '0')
firstWord = Math.max(firstWord - 1, 0)
var i = lastWord
while (i >= firstWord) {
Expand Down
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