[Str] add after and before helpers (#102)

src/Psl/Internal/Loader.php

@@ -215,6 +215,7 @@ final class Loader
         'Psl\Str\Byte\search',
         'Psl\Str\Byte\search_ci',
         'Psl\Str\Byte\search_last',
+        'Psl\Str\Byte\search_last_ci',
         'Psl\Str\Byte\shuffle',
         'Psl\Str\Byte\slice',
         'Psl\Str\Byte\splice',
@@ -229,6 +230,14 @@ final class Loader
         'Psl\Str\Byte\uppercase',
         'Psl\Str\Byte\words',
         'Psl\Str\Byte\wrap',
+        'Psl\Str\Byte\after',
+        'Psl\Str\Byte\after_ci',
+        'Psl\Str\Byte\after_last',
+        'Psl\Str\Byte\after_last_ci',
+        'Psl\Str\Byte\before',
+        'Psl\Str\Byte\before_ci',
+        'Psl\Str\Byte\before_last',
+        'Psl\Str\Byte\before_last_ci',
         'Psl\Str\capitalize',
         'Psl\Str\capitalize_words',
         'Psl\Str\chr',
@@ -278,6 +287,14 @@ final class Loader
         'Psl\Str\uppercase',
         'Psl\Str\width',
         'Psl\Str\wrap',
+        'Psl\Str\after',
+        'Psl\Str\after_ci',
+        'Psl\Str\after_last',
+        'Psl\Str\after_last_ci',
+        'Psl\Str\before',
+        'Psl\Str\before_ci',
+        'Psl\Str\before_last',
+        'Psl\Str\before_last_ci',
         'Psl\invariant',
         'Psl\invariant_violation',
         'Psl\sequence',
@@ -353,6 +370,14 @@ final class Loader
         'Psl\Str\Grapheme\starts_with_ci',
         'Psl\Str\Grapheme\strip_prefix',
         'Psl\Str\Grapheme\strip_suffix',
+        'Psl\Str\Grapheme\after',
+        'Psl\Str\Grapheme\after_ci',
+        'Psl\Str\Grapheme\after_last',
+        'Psl\Str\Grapheme\after_last_ci',
+        'Psl\Str\Grapheme\before',
+        'Psl\Str\Grapheme\before_ci',
+        'Psl\Str\Grapheme\before_last',
+        'Psl\Str\Grapheme\before_last_ci',
     ];
 
     public const INTERFACES = [

src/Psl/Str/Byte/after.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function after(string $haystack, string $needle, int $offset = 0): ?string
+{
+    $position = search($haystack, $needle, $offset);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position);
+}

src/Psl/Str/Byte/after_ci.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function after_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $position = search_ci($haystack, $needle, $offset);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position);
+}

src/Psl/Str/Byte/after_last.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function after_last(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $position = search_last($haystack, $needle, $offset);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position);
+}

src/Psl/Str/Byte/after_last_ci.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function after_last_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $position = search_last_ci($haystack, $needle, $offset);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position);
+}

src/Psl/Str/Byte/before.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function before(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $length = search($haystack, $needle, $offset);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length);
+}

src/Psl/Str/Byte/before_ci.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function before_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $length = search_ci($haystack, $needle, $offset);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length);
+}

src/Psl/Str/Byte/before_last.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function before_last(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $length = search_last($haystack, $needle, $offset);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length);
+}

src/Psl/Str/Byte/before_last_ci.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function before_last_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $length = search_last_ci($haystack, $needle, $offset);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length);
+}

src/Psl/Str/Byte/search_last.php

@@ -23,6 +23,10 @@ use function strrpos;
  */
 function search_last(string $haystack, string $needle, int $offset = 0): ?int
 {
+    if ('' === $needle) {
+        return null;
+    }
+
     $haystack_length = length($haystack);
     Psl\invariant($offset >= -$haystack_length && $offset <= $haystack_length, 'Offset is out-of-bounds.');
 

src/Psl/Str/Byte/search_last_ci.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Byte;
+
+use Psl;
+
+/**
+ * Returns the last position of the 'needle' string in the 'haystack' string,
+ * or null if it isn't found (case-insensitive).
+ *
+ * An optional offset determines where in the haystack (from the beginning) the
+ * search begins. If the offset is negative, the search will begin that many
+ * characters from the end of the string and go backwards. If the offset is
+ * out-of-bounds, an InvariantViolationException will be thrown.
+ *
+ * @psalm-pure
+ *
+ * @throws Psl\Exception\InvariantViolationException If $offset is out-of-bounds.
+ */
+function search_last_ci(string $haystack, string $needle, int $offset = 0): ?int
+{
+    if ('' === $needle) {
+        return null;
+    }
+
+    $haystack_length = length($haystack);
+    Psl\invariant($offset >= -$haystack_length && $offset <= $haystack_length, 'Offset is out-of-bounds.');
+
+    return false === ($pos = strripos($haystack, $needle, $offset)) ? null : $pos;
+}

src/Psl/Str/Grapheme/after.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function after(string $haystack, string $needle, int $offset = 0): ?string
+{
+    $position = search($haystack, $needle, $offset);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position);
+}

src/Psl/Str/Grapheme/after_ci.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function after_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $position = search_ci($haystack, $needle, $offset);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position);
+}

src/Psl/Str/Grapheme/after_last.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function after_last(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $position = search_last($haystack, $needle, $offset);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position);
+}

src/Psl/Str/Grapheme/after_last_ci.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function after_last_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $position = search_last_ci($haystack, $needle, $offset);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position);
+}

src/Psl/Str/Grapheme/before.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function before(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $length = search($haystack, $needle, $offset);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length);
+}

src/Psl/Str/Grapheme/before_ci.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function before_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $length = search_ci($haystack, $needle, $offset);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length);
+}

src/Psl/Str/Grapheme/before_last.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function before_last(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $length = search_last($haystack, $needle, $offset);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length);
+}

src/Psl/Str/Grapheme/before_last_ci.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ *
+ * @psalm-pure
+ */
+function before_last_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0
+): ?string {
+    $length = search_last_ci($haystack, $needle, $offset);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length);
+}

src/Psl/Str/after.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function after(
+    string $haystack,
+    string $needle,
+    int $offset = 0,
+    ?string $encoding = null
+): ?string {
+    $position = search($haystack, $needle, $offset, $encoding);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position, null, $encoding);
+}

src/Psl/Str/after_ci.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function after_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0,
+    ?string $encoding = null
+): ?string {
+    $position = search_ci($haystack, $needle, $offset, $encoding);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position, null, $encoding);
+}

src/Psl/Str/after_last.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function after_last(
+    string $haystack,
+    string $needle,
+    int $offset = 0,
+    ?string $encoding = null
+): ?string {
+    $position = search_last($haystack, $needle, $offset, $encoding);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position, null, $encoding);
+}

src/Psl/Str/after_last_ci.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function after_last_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0,
+    ?string $encoding = null
+): ?string {
+    $position = search_last_ci($haystack, $needle, $offset, $encoding);
+    if (null === $position) {
+        return null;
+    }
+
+    $position += length($needle);
+
+    return slice($haystack, $position, null, $encoding);
+}

src/Psl/Str/before.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function before(
+    string $haystack,
+    string $needle,
+    int $offset = 0,
+    ?string $encoding = null
+): ?string {
+    $length = search($haystack, $needle, $offset, $encoding);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length, $encoding);
+}

src/Psl/Str/before_ci.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function before_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0,
+    ?string $encoding = null
+): ?string {
+    $length = search_ci($haystack, $needle, $offset, $encoding);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length, $encoding);
+}

src/Psl/Str/before_last.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function before_last(
+    string $haystack,
+    string $needle,
+    int $offset = 0,
+    ?string $encoding = null
+): ?string {
+    $length = search_last($haystack, $needle, $offset, $encoding);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length, $encoding);
+}

src/Psl/Str/before_last_ci.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str;
+
+use Psl;
+
+/**
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ * @throws Psl\Exception\InvariantViolationException If an invalid $encoding is provided.
+ *
+ * @psalm-pure
+ */
+function before_last_ci(
+    string $haystack,
+    string $needle,
+    int $offset = 0,
+    ?string $encoding = null
+): ?string {
+    $length = search_last_ci($haystack, $needle, $offset, $encoding);
+    if (null === $length) {
+        return null;
+    }
+
+    return slice($haystack, 0, $length, $encoding);
+}

tests/Psl/Str/AfterCiTest.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str;
+
+final class AfterCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset,
+        ?string $encoding
+    ): void {
+        static::assertSame($expected, Str\after_ci($haystack, $needle, $offset, $encoding));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0, null],
+            ['orld!', 'Hello, World!', 'W', 0, null],
+            ['!', '🤷!', '🤷', 0, null],
+            [null, 'مرحبا بكم', '', 0, null],
+            [null, 'مرحبا بكم', 'ß', 0, null],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0, null],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            [', wôrld!', 'ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            ['好', '你好', '你', 0, null],
+            ['にちは世界', 'こんにちは世界', 'こん', 0, null],
+            ['สดี', 'สวัสดี', 'วั', 0, null],
+            [', world!', 'Hello, world!', 'o', 0, null],
+            ['rld!', 'Hello, world!', 'o', 7, null],
+        ];
+    }
+}

tests/Psl/Str/AfterLastCiTest.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str;
+
+final class AfterLastCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset,
+        ?string $encoding
+    ): void {
+        static::assertSame($expected, Str\after_last_ci($haystack, $needle, $offset, $encoding));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0, null],
+            ['orld!', 'Hello, World!', 'W', 0, null],
+            ['!', '🤷!', '🤷', 0, null],
+            [null, 'مرحبا بكم', '', 0, null],
+            [null, 'مرحبا بكم', 'ß', 0, null],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0, null],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            [', wôrld!', 'ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            ['好', '你好', '你', 0, null],
+            ['にちは世界', 'こんにちは世界', 'こん', 0, null],
+            ['สดี', 'สวัสดี', 'วั', 0, null],
+            ['rld!', 'Hello, world!', 'o', 0, null],
+            ['rld!', 'Hello, world!', 'o', 7, null],
+        ];
+    }
+}

tests/Psl/Str/AfterLastTest.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str;
+
+final class AfterLastTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset,
+        ?string $encoding
+    ): void {
+        static::assertSame($expected, Str\after_last($haystack, $needle, $offset, $encoding));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0, null],
+            ['orld!', 'Hello, World!', 'W', 0, null],
+            ['!', '🤷!', '🤷', 0, null],
+            [null, 'مرحبا بكم', '', 0, null],
+            [null, 'مرحبا بكم', 'ß', 0, null],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0, null],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            ['好', '你好', '你', 0, null],
+            ['にちは世界', 'こんにちは世界', 'こん', 0, null],
+            ['สดี', 'สวัสดี', 'วั', 0, null],
+            ['rld!', 'Hello, world!', 'o', 0, null],
+            ['rld!', 'Hello, world!', 'o', 7, null],
+        ];
+    }
+}

tests/Psl/Str/AfterTest.php

@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str;
+
+final class AfterTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset,
+        ?string $encoding
+    ): void {
+        static::assertSame($expected, Str\after($haystack, $needle, $offset, $encoding));
+    }
+
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0, null],
+            ['orld!', 'Hello, World!', 'W', 0, null],
+            ['!', '🤷!', '🤷', 0, null],
+            [null, 'مرحبا بكم', '', 0, null],
+            [null, 'مرحبا بكم', 'ß', 0, null],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0, null],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            ['好', '你好', '你', 0, null],
+            ['にちは世界', 'こんにちは世界', 'こん', 0, null],
+            ['สดี', 'สวัสดี', 'วั', 0, null],
+            [', world!', 'Hello, world!', 'o', 0, null],
+            ['rld!', 'Hello, world!', 'o', 7, null],
+        ];
+    }
+}

tests/Psl/Str/BeforeCiTest.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str;
+
+final class BeforeCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset,
+        ?string $encoding
+    ): void {
+        static::assertSame($expected, Str\before_ci($haystack, $needle, $offset, $encoding));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0, null],
+            ['Hello, ', 'Hello, World!', 'W', 0, null],
+            ['', '🤷!', '🤷', 0, null],
+            [null, 'مرحبا بكم', '', 0, null],
+            [null, 'مرحبا بكم', 'ß', 0, null],
+            ['', 'héllö, wôrld!', 'héllö', 0, null],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            ['', 'ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            ['', 'Ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            ['héllö, ', 'héllö, wôrld!', 'w', 0, null],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'w', 0, null],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'w', 0, null],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'w', 0, null],
+            ['Ḫéllö, ', 'Ḫéllö, wôrld!', 'w', 0, null],
+            ['你', '你好', '好', 0, null],
+            ['', '你好', '你', 0, null],
+            ['こんにちは世', 'こんにちは世界', '界', 0, null],
+            ['こんに', 'こんにちは世界', 'ち', 0, null],
+            ['ส ว ั ส ด', 'ส ว ั ส ด ี', ' ี', 0, null],
+            ['Hell', 'Hello, world!', 'o', 0, null],
+            ['Hello, w', 'Hello, world!', 'o', 7, null],
+        ];
+    }
+}

tests/Psl/Str/BeforeLastCiTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str;
+
+final class BeforeLastCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset,
+        ?string $encoding
+    ): void {
+        static::assertSame($expected, Str\before_last_ci($haystack, $needle, $offset, $encoding));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0, null],
+            ['Hello, ', 'Hello, World!', 'W', 0, null],
+            ['', '🤷!', '🤷', 0, null],
+            [null, 'مرحبا بكم', '', 0, null],
+            [null, 'مرحبا بكم', 'ß', 0, null],
+            ['', 'héllö, wôrld!', 'héllö', 0, null],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            ['', 'ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            ['', 'Ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            ['héllö, ', 'héllö, Wôrld!', 'wôrld', 0, null],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'Wôrld', 0, null],
+            ['ḫéllö, ', 'ḫéllö, Wôrld!', 'wôrld', 0, null],
+            ['Ḫéllö, ', 'Ḫéllö, wôrld!', 'Wôrld', 0, null],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'wôrld', 0, null],
+            ['你', '你好', '好', 0, null],
+            ['こんにちは', 'こんにちは世界', '世界', 0, null],
+            ['สวัส', 'สวัสดี', 'ดี', 0, null],
+            ['Hello, w', 'Hello, world!', 'o', 0, null],
+            ['Hello, w', 'Hello, world!', 'o', 7, null],
+        ];
+    }
+}

tests/Psl/Str/BeforeLastTest.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str;
+
+final class BeforeLastTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset,
+        ?string $encoding
+    ): void {
+        static::assertSame($expected, Str\before_last($haystack, $needle, $offset, $encoding));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0, null],
+            ['Hello, ', 'Hello, World!', 'W', 0, null],
+            ['', '🤷!', '🤷', 0, null],
+            [null, 'مرحبا بكم', '', 0, null],
+            [null, 'مرحبا بكم', 'ß', 0, null],
+            ['', 'héllö, wôrld!', 'héllö', 0, null],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            [null, 'héllö, Wôrld!', 'wôrld', 0, null],
+            [null, 'ḫéllö, wôrld!', 'Wôrld', 0, null],
+            [null, 'ḫéllö, Wôrld!', 'wôrld', 0, null],
+            [null, 'Ḫéllö, wôrld!', 'Wôrld', 0, null],
+            [null, 'Ḫéllö, Wôrld!', 'wôrld', 0, null],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'Wôrld', 0, null],
+            ['你', '你好', '好', 0, null],
+            ['こんにちは', 'こんにちは世界', '世界', 0, null],
+            ['สวัส', 'สวัสดี', 'ดี', 0, null],
+            ['Hello, w', 'Hello, world!', 'o', 0, null],
+            ['Hello, w', 'Hello, world!', 'o', 7, null],
+        ];
+    }
+}

tests/Psl/Str/BeforeTest.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str;
+
+final class BeforeTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset,
+        ?string $encoding
+    ): void {
+        static::assertSame($expected, Str\before($haystack, $needle, $offset, $encoding));
+    }
+
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0, null],
+            ['Hello, ', 'Hello, World!', 'W', 0, null],
+            ['', '🤷!', '🤷', 0, null],
+            [null, 'مرحبا بكم', '', 0, null],
+            [null, 'مرحبا بكم', 'ß', 0, null],
+            ['', 'héllö, wôrld!', 'héllö', 0, null],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0, null],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0, null],
+            [null, 'héllö, Wôrld!', 'wôrld', 0, null],
+            [null, 'ḫéllö, wôrld!', 'Wôrld', 0, null],
+            [null, 'ḫéllö, Wôrld!', 'wôrld', 0, null],
+            [null, 'Ḫéllö, wôrld!', 'Wôrld', 0, null],
+            [null, 'Ḫéllö, Wôrld!', 'wôrld', 0, null],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'Wôrld', 0, null],
+            ['你', '你好', '好', 0, null],
+            ['こんにちは', 'こんにちは世界', '世界', 0, null],
+            ['สวัส', 'สวัสดี', 'ดี', 0, null],
+            ['Hell', 'Hello, world!', 'o', 0, null],
+            ['Hello, w', 'Hello, world!', 'o', 7, null],
+        ];
+    }
+}

tests/Psl/Str/Byte/AfterCiTest.php

@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Byte;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Byte;
+
+final class AfterCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Byte\after_ci($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['orld!', 'Hello, World!', 'W', 0],
+            ['!', '🤷!', '🤷', 0],
+            ['', '🤷!', '!', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', world!', 'Hello, world!', 'Hello', 0],
+            [', world!', 'Hello, world!', 'hello', 0],
+            [', world!', 'hello, world!', 'Hello', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['好', '你好', '你', 0],
+            ['にちは世界', 'こんにちは世界', 'こん', 0],
+            ['สดี', 'สวัสดี', 'วั', 0],
+            [', world!', 'Hello, world!', 'o', 0],
+            ['rld!', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Byte/AfterLastCiTest.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Byte;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Byte;
+
+final class AfterLastCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Byte\after_last_ci($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['orld!', 'Hello, World!', 'W', 0],
+            ['!', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['好', '你好', '你', 0],
+            ['にちは世界', 'こんにちは世界', 'こん', 0],
+            ['สดี', 'สวัสดี', 'วั', 0],
+            ['rld!', 'Hello, world!', 'o', 0],
+            ['rld!', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Byte/AfterLastTest.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Byte;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Byte;
+
+final class AfterLastTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Byte\after_last($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['orld!', 'Hello, World!', 'W', 0],
+            ['!', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['好', '你好', '你', 0],
+            ['にちは世界', 'こんにちは世界', 'こん', 0],
+            ['สดี', 'สวัสดี', 'วั', 0],
+            ['rld!', 'Hello, world!', 'o', 0],
+            ['rld!', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Byte/AfterTest.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Byte;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Byte;
+
+final class AfterTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Byte\after($haystack, $needle, $offset));
+    }
+
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['orld!', 'Hello, World!', 'W', 0],
+            ['!', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['好', '你好', '你', 0],
+            ['にちは世界', 'こんにちは世界', 'こん', 0],
+            ['สดี', 'สวัสดี', 'วั', 0],
+            [', world!', 'Hello, world!', 'o', 0],
+            ['rld!', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Byte/BeforeCiTest.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Byte;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Byte;
+
+final class BeforeCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Byte\before_ci($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['Hello, ', 'Hello, World!', 'W', 0],
+            ['', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            ['', 'héllö, wôrld!', 'héllö', 0],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['héllö, ', 'héllö, wôrld!', 'w', 0],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'w', 0],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'w', 0],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'w', 0],
+            ['Ḫéllö, ', 'Ḫéllö, wôrld!', 'w', 0],
+            ['你', '你好', '好', 0],
+            ['', '你好', '你', 0],
+            ['こんにちは世', 'こんにちは世界', '界', 0],
+            ['こんに', 'こんにちは世界', 'ち', 0],
+            ['ส ว ั ส ด', 'ส ว ั ส ด ี', ' ี', 0],
+            ['Hell', 'Hello, world!', 'o', 0],
+            ['Hello, w', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Byte/BeforeLastCiTest.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Byte;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Byte;
+
+final class BeforeLastCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Byte\before_last_ci($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['Hello, ', 'Hello, World!', 'W', 0],
+            ['', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            ['', 'héllö, wôrld!', 'héllö', 0],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['héllö, ', 'héllö, Wôrld!', 'wôrld', 0],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'Wôrld', 0],
+            ['ḫéllö, ', 'ḫéllö, Wôrld!', 'wôrld', 0],
+            ['Ḫéllö, ', 'Ḫéllö, wôrld!', 'Wôrld', 0],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'wôrld', 0],
+            ['你', '你好', '好', 0],
+            ['こんにちは', 'こんにちは世界', '世界', 0],
+            ['สวัส', 'สวัสดี', 'ดี', 0],
+            ['Hello, w', 'Hello, world!', 'o', 0],
+            ['Hello, w', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Byte/BeforeLastTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Byte;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Byte;
+
+final class BeforeLastTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Byte\before_last($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['Hello, ', 'Hello, World!', 'W', 0],
+            ['', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            ['', 'héllö, wôrld!', 'héllö', 0],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'héllö, Wôrld!', 'wôrld', 0],
+            [null, 'ḫéllö, wôrld!', 'Wôrld', 0],
+            [null, 'ḫéllö, Wôrld!', 'wôrld', 0],
+            [null, 'Ḫéllö, wôrld!', 'Wôrld', 0],
+            [null, 'Ḫéllö, Wôrld!', 'wôrld', 0],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'Wôrld', 0],
+            ['你', '你好', '好', 0],
+            ['こんにちは', 'こんにちは世界', '世界', 0],
+            ['สวัส', 'สวัสดี', 'ดี', 0],
+            ['Hello, w', 'Hello, world!', 'o', 0],
+            ['Hello, w', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Byte/BeforeTest.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Byte;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Byte;
+
+final class BeforeTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Byte\before($haystack, $needle, $offset));
+    }
+
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['Hello, ', 'Hello, World!', 'W', 0],
+            ['', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            ['', 'héllö, wôrld!', 'héllö', 0],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'héllö, Wôrld!', 'wôrld', 0],
+            [null, 'ḫéllö, wôrld!', 'Wôrld', 0],
+            [null, 'ḫéllö, Wôrld!', 'wôrld', 0],
+            [null, 'Ḫéllö, wôrld!', 'Wôrld', 0],
+            [null, 'Ḫéllö, Wôrld!', 'wôrld', 0],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'Wôrld', 0],
+            ['你', '你好', '好', 0],
+            ['こんにちは', 'こんにちは世界', '世界', 0],
+            ['สวัส', 'สวัสดี', 'ดี', 0],
+            ['Hell', 'Hello, world!', 'o', 0],
+            ['Hello, w', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Grapheme/AfterCiTest.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Grapheme;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Grapheme;
+
+final class AfterCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Grapheme\after_ci($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['orld!', 'Hello, World!', 'W', 0],
+            ['!', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', world!', 'Hello, world!', 'Hello', 0],
+            [', world!', 'Hello, world!', 'hello', 0],
+            [', world!', 'hello, world!', 'Hello', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['好', '你好', '你', 0],
+            ['にちは世界', 'こんにちは世界', 'こん', 0],
+            ['สดี', 'สวัสดี', 'วั', 0],
+            [', world!', 'Hello, world!', 'o', 0],
+            ['rld!', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Grapheme/AfterLastCiTest.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Grapheme;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Grapheme;
+
+final class AfterLastCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Grapheme\after_last_ci($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['orld!', 'Hello, World!', 'W', 0],
+            ['!', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['好', '你好', '你', 0],
+            ['にちは世界', 'こんにちは世界', 'こん', 0],
+            ['สดี', 'สวัสดี', 'วั', 0],
+            ['rld!', 'Hello, world!', 'o', 0],
+            ['rld!', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Grapheme/AfterLastTest.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Grapheme;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Grapheme;
+
+final class AfterLastTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Grapheme\after_last($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['orld!', 'Hello, World!', 'W', 0],
+            ['!', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['好', '你好', '你', 0],
+            ['にちは世界', 'こんにちは世界', 'こん', 0],
+            ['สดี', 'สวัสดี', 'วั', 0],
+            ['rld!', 'Hello, world!', 'o', 0],
+            ['rld!', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Grapheme/AfterTest.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Grapheme;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Grapheme;
+
+final class AfterTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Grapheme\after($haystack, $needle, $offset));
+    }
+
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['orld!', 'Hello, World!', 'W', 0],
+            ['!', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            [', wôrld!', 'héllö, wôrld!', 'héllö', 0],
+            [', wôrld!', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [', wôrld!', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['好', '你好', '你', 0],
+            ['にちは世界', 'こんにちは世界', 'こん', 0],
+            ['สดี', 'สวัสดี', 'วั', 0],
+            [', world!', 'Hello, world!', 'o', 0],
+            ['rld!', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Grapheme/BeforeCiTest.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Grapheme;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Grapheme;
+
+final class BeforeCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Grapheme\before_ci($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['Hello, ', 'Hello, World!', 'W', 0],
+            ['', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            ['', 'héllö, wôrld!', 'héllö', 0],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['', 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['héllö, ', 'héllö, wôrld!', 'w', 0],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'w', 0],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'w', 0],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'w', 0],
+            ['Ḫéllö, ', 'Ḫéllö, wôrld!', 'w', 0],
+            ['你', '你好', '好', 0],
+            ['', '你好', '你', 0],
+            ['こんにちは世', 'こんにちは世界', '界', 0],
+            ['こんに', 'こんにちは世界', 'ち', 0],
+            ['ส ว ั ส ด', 'ส ว ั ส ด ี', ' ี', 0],
+            ['Hell', 'Hello, world!', 'o', 0],
+            ['Hello, w', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Grapheme/BeforeLastCiTest.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Grapheme;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Grapheme;
+
+final class BeforeLastCiTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Grapheme\before_last_ci($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['Hello, ', 'Hello, World!', 'W', 0],
+            ['', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            ['', 'héllö, wôrld!', 'héllö', 0],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['', 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            ['héllö, ', 'héllö, Wôrld!', 'wôrld', 0],
+            ['ḫéllö, ', 'ḫéllö, wôrld!', 'Wôrld', 0],
+            ['ḫéllö, ', 'ḫéllö, Wôrld!', 'wôrld', 0],
+            ['Ḫéllö, ', 'Ḫéllö, wôrld!', 'Wôrld', 0],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'wôrld', 0],
+            ['你', '你好', '好', 0],
+            ['こんにちは', 'こんにちは世界', '世界', 0],
+            ['สวัส', 'สวัสดี', 'ดี', 0],
+            ['Hello, w', 'Hello, world!', 'o', 0],
+            ['Hello, w', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Grapheme/BeforeLastTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Grapheme;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Grapheme;
+
+final class BeforeLastTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Grapheme\before_last($haystack, $needle, $offset));
+    }
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['Hello, ', 'Hello, World!', 'W', 0],
+            ['', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            ['', 'héllö, wôrld!', 'héllö', 0],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'héllö, Wôrld!', 'wôrld', 0],
+            [null, 'ḫéllö, wôrld!', 'Wôrld', 0],
+            [null, 'ḫéllö, Wôrld!', 'wôrld', 0],
+            [null, 'Ḫéllö, wôrld!', 'Wôrld', 0],
+            [null, 'Ḫéllö, Wôrld!', 'wôrld', 0],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'Wôrld', 0],
+            ['你', '你好', '好', 0],
+            ['こんにちは', 'こんにちは世界', '世界', 0],
+            ['สวัส', 'สวัสดี', 'ดี', 0],
+            ['Hello, w', 'Hello, world!', 'o', 0],
+            ['Hello, w', 'Hello, world!', 'o', 7],
+        ];
+    }
+}

tests/Psl/Str/Grapheme/BeforeTest.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Str\Grapheme;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Str\Grapheme;
+
+final class BeforeTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testAfter(
+        ?string $expected,
+        string $haystack,
+        string $needle,
+        int $offset
+    ): void {
+        static::assertSame($expected, Grapheme\before($haystack, $needle, $offset));
+    }
+
+
+    public function provideData(): array
+    {
+        return [
+            [null, '', '',  0],
+            ['Hello, ', 'Hello, World!', 'W', 0],
+            ['', '🤷!', '🤷', 0],
+            [null, 'مرحبا بكم', '', 0],
+            [null, 'مرحبا بكم', 'ß', 0],
+            ['', 'héllö, wôrld!', 'héllö', 0],
+            ['', 'ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'ḫéllö, wôrld!', 'Ḫéllö', 0],
+            ['', 'Ḫéllö, wôrld!', 'Ḫéllö', 0],
+            [null, 'Ḫéllö, wôrld!', 'ḫéllö', 0],
+            [null, 'héllö, Wôrld!', 'wôrld', 0],
+            [null, 'ḫéllö, wôrld!', 'Wôrld', 0],
+            [null, 'ḫéllö, Wôrld!', 'wôrld', 0],
+            [null, 'Ḫéllö, wôrld!', 'Wôrld', 0],
+            [null, 'Ḫéllö, Wôrld!', 'wôrld', 0],
+            ['Ḫéllö, ', 'Ḫéllö, Wôrld!', 'Wôrld', 0],
+            ['你', '你好', '好', 0],
+            ['こんにちは', 'こんにちは世界', '世界', 0],
+            ['สวัส', 'สวัสดี', 'ดี', 0],
+            ['Hell', 'Hello, world!', 'o', 0],
+            ['Hello, w', 'Hello, world!', 'o', 7],
+        ];
+    }
+}