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pjfanningpjfanning
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more fully copy Netty Two-Way string matching impl
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2 files changed

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‎actor/src/main/scala/org/apache/pekko/util/ByteString.scala‎

Lines changed: 112 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -329,6 +329,62 @@ object ByteString {
329329
else -1
330330
}
331331

332+
// Derived from code in Netty
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// https://github.com/netty/netty/blob/d28a0fc6598b50fbe8f296831777cf4b653a475f/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java#L242-L325
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override def indexOfSlice(slice: Array[Byte], from: Int): Int = {
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val n = length - from
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val m = slice.length
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if (m == 0) return 0
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// When the needle has only one byte that can be read,
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// the indexOf() can be used
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if (m == 1) return indexOf(slice.head, from)
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var i = 0
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var j = 0
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val aStartIndex = 0
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val bStartIndex = from
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val suffixes = SWARUtil.maxSuf(slice, m, aStartIndex, true)
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val prefixes = SWARUtil.maxSuf(slice, m, aStartIndex, false)
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val ell = Math.max((suffixes >> 32).toInt, (prefixes >> 32).toInt)
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var per = Math.max(suffixes.toInt, prefixes.toInt)
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var memory = 0
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val checkLen = Math.min(m - per, ell + 1)
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if (SWARUtil.arrayBytesMatch(slice, aStartIndex, slice, aStartIndex + per, checkLen)) {
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memory = -1
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while (j <= n - m) {
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i = Math.max(ell, memory) + 1
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while (i < m && (slice(i + aStartIndex) == bytes(i + j + bStartIndex))) i += 1
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if (i > n) return -1
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if (i >= m) {
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i = ell
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while (i > memory && (slice(i + aStartIndex) == bytes(i + j + bStartIndex))) i -= 1
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if (i <= memory) return j + bStartIndex
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j += per
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memory = m - per - 1
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}
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else {
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j += i - ell
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memory = -1
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}
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}
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}
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else {
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per = Math.max(ell + 1, m - ell - 1) + 1
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while (j <= n - m) {
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i = ell + 1
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while (i < m && (slice(i + aStartIndex) == bytes(i + j + bStartIndex))) i += 1
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if (i > n) return -1
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if (i >= m) {
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i = ell
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while (i >= 0 && (slice(i + aStartIndex) == bytes(i + j + bStartIndex))) i -= 1
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if (i < 0) return j + bStartIndex
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j += per
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}
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else j += i - ell
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}
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}
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-1
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}
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332388
// Derived from code in Netty
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// https://github.com/netty/netty/blob/d28a0fc6598b50fbe8f296831777cf4b653a475f/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java#L366-L408
334390
override private[util] def bytesMatch(fromIndex: Int, checkBytes: Array[Byte], bytesFromIndex: Int,
@@ -615,6 +671,62 @@ object ByteString {
615671
else -1
616672
}
617673

674+
// Derived from code in Netty
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// https://github.com/netty/netty/blob/d28a0fc6598b50fbe8f296831777cf4b653a475f/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java#L242-L325
676+
override def indexOfSlice(slice: Array[Byte], from: Int): Int = {
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val n = length - from
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val m = slice.length
679+
if (m == 0) return 0
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// When the needle has only one byte that can be read,
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// the indexOf() can be used
682+
if (m == 1) return indexOf(slice.head, from)
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var i = 0
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var j = 0
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val aStartIndex = 0
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val bStartIndex = from + startIndex
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val suffixes = SWARUtil.maxSuf(slice, m, aStartIndex, true)
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val prefixes = SWARUtil.maxSuf(slice, m, aStartIndex, false)
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val ell = Math.max((suffixes >> 32).toInt, (prefixes >> 32).toInt)
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var per = Math.max(suffixes.toInt, prefixes.toInt)
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var memory = 0
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val checkLen = Math.min(m - per, ell + 1)
693+
if (SWARUtil.arrayBytesMatch(slice, aStartIndex, slice, aStartIndex + per, checkLen)) {
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memory = -1
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while (j <= n - m) {
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i = Math.max(ell, memory) + 1
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while (i < m && (slice(i + aStartIndex) == bytes(i + j + bStartIndex))) i += 1
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if (i > n) return -1
699+
if (i >= m) {
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i = ell
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while (i > memory && (slice(i + aStartIndex) == bytes(i + j + bStartIndex))) i -= 1
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if (i <= memory) return j + bStartIndex - startIndex
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j += per
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memory = m - per - 1
705+
}
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else {
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j += i - ell
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memory = -1
709+
}
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}
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}
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else {
713+
per = Math.max(ell + 1, m - ell - 1) + 1
714+
while (j <= n - m) {
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i = ell + 1
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while (i < m && (slice(i + aStartIndex) == bytes(i + j + bStartIndex))) i += 1
717+
if (i > n) return -1
718+
if (i >= m) {
719+
i = ell
720+
while (i >= 0 && (slice(i + aStartIndex) == bytes(i + j + bStartIndex))) i -= 1
721+
if (i < 0) return j + bStartIndex - startIndex
722+
j += per
723+
}
724+
else j += i - ell
725+
}
726+
}
727+
-1
728+
}
729+
618730
// Derived from code in Netty
619731
// https://github.com/netty/netty/blob/d28a0fc6598b50fbe8f296831777cf4b653a475f/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java#L366-L408
620732
override private[util] def bytesMatch(fromIndex: Int,

‎actor/src/main/scala/org/apache/pekko/util/SWARUtil.scala‎

Lines changed: 62 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -93,4 +93,66 @@ private[util] object SWARUtil {
9393
(array(index + 7).toLong & 0xFF)
9494
}
9595
}
96+
97+
// Derived from code in Netty
98+
// https://github.com/netty/netty/blob/d28a0fc6598b50fbe8f296831777cf4b653a475f/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java#L366-L408
99+
def arrayBytesMatch(arrayBytes: Array[Byte],
100+
fromIndex: Int,
101+
checkBytes: Array[Byte],
102+
bytesFromIndex: Int,
103+
checkLength: Int): Boolean = {
104+
var aIndex = fromIndex
105+
var bIndex = bytesFromIndex
106+
val longCount = checkLength >>> 3
107+
val byteCount = checkLength & 7
108+
var i = 0
109+
while (i < longCount) {
110+
if (SWARUtil.getLong(arrayBytes, aIndex) != SWARUtil.getLong(checkBytes, bIndex)) return false
111+
aIndex += 8
112+
bIndex += 8
113+
i += 1
114+
}
115+
i = 0
116+
while (i < byteCount) {
117+
if (arrayBytes(aIndex) != checkBytes(bIndex)) return false
118+
aIndex += 1
119+
bIndex += 1
120+
i += 1
121+
}
122+
true
123+
}
124+
125+
// Derived from code in Netty
126+
// https://github.com/netty/netty/blob/a5343227b10456ec889a3fdc5fa4246f036a216d/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java#L327-L356
127+
def maxSuf(arrayBytes: Array[Byte], m: Int, start: Int, isSuffix: Boolean): Long = {
128+
var p = 1
129+
var ms = -1
130+
var j = start
131+
var k = 1
132+
var a = 0
133+
var b = 0
134+
while (j + k < m) {
135+
a = arrayBytes(j + k)
136+
b = arrayBytes(ms + k)
137+
val suffix = if (isSuffix) a < b
138+
else a > b
139+
if (suffix) {
140+
j += k
141+
k = 1
142+
p = j - ms
143+
}
144+
else if (a == b) if (k != p) k += 1
145+
else {
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j += p
147+
k = 1
148+
}
149+
else {
150+
ms = j
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j = ms + 1
152+
k = 1
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p = 1
154+
}
155+
}
156+
(ms.toLong << 32) + p
157+
}
96158
}

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