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Parsing Unicode escape sequences (#21)
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Lines changed: 677 additions & 259 deletions

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‎README.md‎

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@@ -8,12 +8,6 @@ A Java version of [simdjson](https://github.com/simdjson/simdjson) - a JSON pars
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based on the paper [Parsing Gigabytes of JSON per Second](https://arxiv.org/abs/1902.08318)
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by Geoff Langdale and Daniel Lemire.
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This implementation is still missing several features available in simdsjon. For example:
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* Support for Unicode characters
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* UTF-8 validation
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* Support for 512-bit vectors
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## Code Sample
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```java
@@ -73,8 +67,8 @@ This section presents a performance comparison of different JSON parsers availab
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the [twitter.json](src/jmh/resources/twitter.json) dataset, and its goal was to measure the throughput (ops/s) of parsing
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and finding all unique users with a default profile.
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**Note that simdjson-java is still missing several features (mentioned in the introduction), so the following results
77-
may not reflect its real performance.**
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**Note that simdjson-java is still missing several features (see [GitHub Issues](https://github.com/simdjson/simdjson-java/issues)),
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so the following results may not reflect its real performance.**
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Environment:
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* CPU: Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz

‎build.gradle‎

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@@ -38,16 +38,18 @@ java {
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ext {
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junitVersion = '5.9.1'
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jsoniterScalaVersion = '2.23.2'
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}
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dependencies {
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jmhImplementation group: 'com.fasterxml.jackson.core', name: 'jackson-databind', version: '2.15.2'
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jmhImplementation group: 'com.alibaba.fastjson2', name: 'fastjson2', version: '2.0.35'
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jmhImplementation group: 'com.jsoniter', name: 'jsoniter', version: '0.9.23'
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jmhImplementation group: 'com.github.plokhotnyuk.jsoniter-scala', name: 'jsoniter-scala-core_2.13', version: '2.23.2'
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compileOnly group: 'com.github.plokhotnyuk.jsoniter-scala', name: 'jsoniter-scala-macros_2.13', version: '2.23.2'
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jmhImplementation group: 'com.github.plokhotnyuk.jsoniter-scala', name: 'jsoniter-scala-core_2.13', version: jsoniterScalaVersion
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compileOnly group: 'com.github.plokhotnyuk.jsoniter-scala', name: 'jsoniter-scala-macros_2.13', version: jsoniterScalaVersion
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testImplementation group: 'org.assertj', name: 'assertj-core', version: '3.24.2'
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testImplementation group: 'org.apache.commons', name: 'commons-text', version: '1.10.0'
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testImplementation group: 'org.junit.jupiter', name: 'junit-jupiter-api', version: junitVersion
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testImplementation group: 'org.junit.jupiter', name: 'junit-jupiter-params', version: junitVersion
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testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: junitVersion
@@ -74,6 +76,9 @@ test {
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'--add-modules', 'jdk.incubator.vector',
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'-Xmx2g'
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]
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testLogging {
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events 'PASSED', 'SKIPPED', 'FAILED', 'STANDARD_OUT', 'STANDARD_ERROR'
81+
}
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}
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tasks.withType(JmhBytecodeGeneratorTask).configureEach {

‎src/jmh/java/org/simdjson/ParseBenchmark.java‎

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@@ -21,7 +21,7 @@
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@OutputTimeUnit(TimeUnit.SECONDS)
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public class ParseBenchmark {
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@Param({"/twitter.json" /*, "/gsoc-2018.json - unicode is not supported yet"*/, "/github_events.json"})
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@Param({"/twitter.json", "/gsoc-2018.json", "/github_events.json"})
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String fileName;
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private final SimdJsonParser simdJsonParser = new SimdJsonParser();

‎src/main/java/org/simdjson/CharacterUtils.java‎

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‎src/main/java/org/simdjson/JsonCharUtils.java‎

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‎src/main/java/org/simdjson/NumberParser.java‎

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@@ -9,7 +9,7 @@
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import static java.lang.Long.remainderUnsigned;
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import static java.lang.Math.abs;
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import static java.lang.Math.unsignedMultiplyHigh;
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import static org.simdjson.JsonCharUtils.isStructuralOrWhitespace;
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import static org.simdjson.CharacterUtils.isStructuralOrWhitespace;
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import static org.simdjson.NumberParserTables.NUMBER_OF_ADDITIONAL_DIGITS_AFTER_LEFT_SHIFT;
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import static org.simdjson.NumberParserTables.POWERS_OF_FIVE;
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import static org.simdjson.NumberParserTables.POWER_OF_FIVE_DIGITS;

‎src/main/java/org/simdjson/StringParser.java‎

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@@ -0,0 +1,127 @@
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package org.simdjson;
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import jdk.incubator.vector.ByteVector;
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import static org.simdjson.CharacterUtils.escape;
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import static org.simdjson.CharacterUtils.hexToInt;
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import static org.simdjson.Tape.STRING;
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class StringParser {
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private static final byte BACKSLASH = '\\';
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private static final byte QUOTE = '"';
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private static final int BYTES_PROCESSED = StructuralIndexer.SPECIES.vectorByteSize();
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private static final int MIN_HIGH_SURROGATE = 0xD800;
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private static final int MAX_HIGH_SURROGATE = 0xDBFF;
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private static final int MIN_LOW_SURROGATE = 0xDC00;
17+
private static final int MAX_LOW_SURROGATE = 0xDFFF;
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private final Tape tape;
20+
private final byte[] stringBuffer;
21+
22+
private int stringBufferIdx;
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StringParser(Tape tape, byte[] stringBuffer) {
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this.tape = tape;
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this.stringBuffer = stringBuffer;
27+
}
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void parseString(byte[] buffer, int idx) {
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tape.append(stringBufferIdx, STRING);
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int src = idx + 1;
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int dst = stringBufferIdx + Integer.BYTES;
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while (true) {
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ByteVector srcVec = ByteVector.fromArray(StructuralIndexer.SPECIES, buffer, src);
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srcVec.intoArray(stringBuffer, dst);
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long backslashBits = srcVec.eq(BACKSLASH).toLong();
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long quoteBits = srcVec.eq(QUOTE).toLong();
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if (hasQuoteFirst(backslashBits, quoteBits)) {
40+
dst += Long.numberOfTrailingZeros(quoteBits);
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break;
42+
}
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if (hasBackslash(backslashBits, quoteBits)) {
44+
int backslashDist = Long.numberOfTrailingZeros(backslashBits);
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byte escapeChar = buffer[src + backslashDist + 1];
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if (escapeChar == 'u') {
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src += backslashDist;
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dst += backslashDist;
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int codePoint = hexToInt(buffer, src + 2);
50+
src += 6;
51+
if (codePoint >= MIN_HIGH_SURROGATE && codePoint <= MAX_HIGH_SURROGATE) {
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codePoint = parseLowSurrogate(buffer, src, codePoint);
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src += 6;
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} else if (codePoint >= MIN_LOW_SURROGATE && codePoint <= MAX_LOW_SURROGATE) {
55+
throw new JsonParsingException("Invalid code point. The range U+DC00–U+DFFF is reserved for low surrogate.");
56+
}
57+
dst += storeCodePointInStringBuffer(codePoint, dst);
58+
} else {
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stringBuffer[dst + backslashDist] = escape(escapeChar);
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src += backslashDist + 2;
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dst += backslashDist + 1;
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}
63+
} else {
64+
src += BYTES_PROCESSED;
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dst += BYTES_PROCESSED;
66+
}
67+
}
68+
int len = dst - stringBufferIdx - Integer.BYTES;
69+
IntegerUtils.toBytes(len, stringBuffer, stringBufferIdx);
70+
stringBufferIdx = dst;
71+
}
72+
73+
private int parseLowSurrogate(byte[] buffer, int src, int codePoint) {
74+
if ((buffer[src] << 8 | buffer[src + 1]) != ('\\' << 8 | 'u')) {
75+
throw new JsonParsingException("Low surrogate should start with '\\u'");
76+
} else {
77+
int codePoint2 = hexToInt(buffer, src + 2);
78+
int lowBit = codePoint2 - MIN_LOW_SURROGATE;
79+
if (lowBit >> 10 == 0) {
80+
return (((codePoint - MIN_HIGH_SURROGATE) << 10) | lowBit) + 0x10000;
81+
} else {
82+
throw new JsonParsingException("Invalid code point. Low surrogate should be in the range U+DC00–U+DFFF.");
83+
}
84+
}
85+
}
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87+
private int storeCodePointInStringBuffer(int codePoint, int dst) {
88+
if (codePoint < 0) {
89+
throw new JsonParsingException("Invalid unicode escape sequence.");
90+
}
91+
if (codePoint <= 0x7F) {
92+
stringBuffer[dst] = (byte) codePoint;
93+
return 1;
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}
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if (codePoint <= 0x7FF) {
96+
stringBuffer[dst] = (byte) ((codePoint >> 6) + 192);
97+
stringBuffer[dst + 1] = (byte) ((codePoint & 63) + 128);
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return 2;
99+
}
100+
if (codePoint <= 0xFFFF) {
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stringBuffer[dst] = (byte) ((codePoint >> 12) + 224);
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stringBuffer[dst + 1] = (byte) (((codePoint >> 6) & 63) + 128);
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stringBuffer[dst + 2] = (byte) ((codePoint & 63) + 128);
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return 3;
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}
106+
if (codePoint <= 0x10FFFF) {
107+
stringBuffer[dst] = (byte) ((codePoint >> 18) + 240);
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stringBuffer[dst + 1] = (byte) (((codePoint >> 12) & 63) + 128);
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stringBuffer[dst + 2] = (byte) (((codePoint >> 6) & 63) + 128);
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stringBuffer[dst + 3] = (byte) ((codePoint & 63) + 128);
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return 4;
112+
}
113+
throw new IllegalStateException("Code point is greater than 0x110000.");
114+
}
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116+
private boolean hasQuoteFirst(long backslashBits, long quoteBits) {
117+
return ((backslashBits - 1) & quoteBits) != 0;
118+
}
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120+
private boolean hasBackslash(long backslashBits, long quoteBits) {
121+
return ((quoteBits - 1) & backslashBits) != 0;
122+
}
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void reset() {
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stringBufferIdx = 0;
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}
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}

‎src/main/java/org/simdjson/TapeBuilder.java‎

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@@ -1,55 +1,27 @@
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package org.simdjson;
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3-
import jdk.incubator.vector.ByteVector;
4-
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import java.util.Arrays;
64

7-
import static org.simdjson.JsonCharUtils.isStructuralOrWhitespace;
5+
import static org.simdjson.CharacterUtils.isStructuralOrWhitespace;
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import static org.simdjson.Tape.END_ARRAY;
97
import static org.simdjson.Tape.END_OBJECT;
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import static org.simdjson.Tape.FALSE_VALUE;
119
import static org.simdjson.Tape.NULL_VALUE;
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import static org.simdjson.Tape.ROOT;
1311
import static org.simdjson.Tape.START_ARRAY;
1412
import static org.simdjson.Tape.START_OBJECT;
15-
import static org.simdjson.Tape.STRING;
1613
import static org.simdjson.Tape.TRUE_VALUE;
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1815
class TapeBuilder {
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2017
private static final byte SPACE = 0x20;
21-
private static final byte BACKSLASH = '\\';
22-
private static final byte QUOTE = '"';
23-
private static final int BYTES_PROCESSED = StructuralIndexer.SPECIES.vectorByteSize();
24-
private static final byte[] ESCAPE_MAP = new byte[]{
25-
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0x0.
26-
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0x22, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x2f,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0x4.
31-
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x5c, 0, 0, 0, // 0x5.
32-
0, 0, 0x08, 0, 0, 0, 0x0c, 0, 0, 0, 0, 0, 0, 0, 0x0a, 0, // 0x6.
33-
0, 0, 0x0d, 0, 0x09, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0x7.
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35-
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
43-
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
44-
};
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4619
private final Tape tape;
4720
private final byte[] stringBuffer;
4821
private final OpenContainer[] openContainers;
4922
private final int padding;
5023
private final NumberParser numberParser;
51-
52-
private int stringBufferIdx;
24+
private final StringParser stringParser;
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5426
TapeBuilder(int capacity, int depth, int padding) {
5527
this.tape = new Tape(capacity);
@@ -60,6 +32,7 @@ class TapeBuilder {
6032
}
6133
this.stringBuffer = new byte[capacity];
6234
this.numberParser = new NumberParser(tape);
35+
this.stringParser = new StringParser(tape, stringBuffer);
6336
}
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6538
void visitDocumentStart() {
@@ -193,56 +166,7 @@ void visitKey(byte[] buffer, int idx) {
193166
}
194167

195168
private void visitString(byte[] buffer, int idx) {
196-
tape.append(stringBufferIdx, STRING);
197-
int src = idx + 1;
198-
int dst = stringBufferIdx + Integer.BYTES;
199-
while (true) {
200-
ByteVector srcVec = ByteVector.fromArray(StructuralIndexer.SPECIES, buffer, src);
201-
srcVec.intoArray(stringBuffer, dst);
202-
long backslashBits = srcVec.eq(BACKSLASH).toLong();
203-
long quoteBits = srcVec.eq(QUOTE).toLong();
204-
205-
if (hasQuoteFirst(backslashBits, quoteBits)) {
206-
dst += Long.numberOfTrailingZeros(quoteBits);
207-
break;
208-
}
209-
if (hasBackslash(backslashBits, quoteBits)) {
210-
int backslashDist = Long.numberOfTrailingZeros(backslashBits);
211-
byte escapeChar = buffer[src + backslashDist + 1];
212-
if (escapeChar == 'u') {
213-
throw new UnsupportedOperationException("Support for unicode characters is not implemented yet.");
214-
} else {
215-
stringBuffer[dst + backslashDist] = escape(escapeChar);
216-
src += backslashDist + 2;
217-
dst += backslashDist + 1;
218-
}
219-
} else {
220-
src += BYTES_PROCESSED;
221-
dst += BYTES_PROCESSED;
222-
}
223-
}
224-
int len = dst - stringBufferIdx - Integer.BYTES;
225-
IntegerUtils.toBytes(len, stringBuffer, stringBufferIdx);
226-
stringBufferIdx = dst;
227-
}
228-
229-
private byte escape(byte escapeChar) {
230-
if (escapeChar < 0) {
231-
throw new JsonParsingException("Escaped unexpected character: " + ((char) escapeChar));
232-
}
233-
byte escapeResult = ESCAPE_MAP[escapeChar];
234-
if (escapeResult == 0) {
235-
throw new JsonParsingException("Escaped unexpected character: " + ((char) escapeChar));
236-
}
237-
return escapeResult;
238-
}
239-
240-
private boolean hasQuoteFirst(long backslashBits, long quoteBits) {
241-
return ((backslashBits - 1) & quoteBits) != 0;
242-
}
243-
244-
private boolean hasBackslash(long backslashBits, long quoteBits) {
245-
return ((quoteBits - 1) & backslashBits) != 0;
169+
stringParser.parseString(buffer, idx);
246170
}
247171

248172
private void visitNumber(byte[] buffer, int idx) {
@@ -278,7 +202,7 @@ private void emptyContainer(char start, char end) {
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279203
void reset() {
280204
tape.reset();
281-
stringBufferIdx = 0;
205+
stringParser.reset();
282206
}
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284208
JsonValue createJsonValue(byte[] buffer) {

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