[Str] add grarpheme support

composer.json

@@ -14,7 +14,8 @@
         "ext-bcmath": "*",
         "ext-mbstring": "*",
         "ext-json": "*",
-        "ext-sodium": "*"
+        "ext-sodium": "*",
+        "ext-intl": "*"
     },
     "require-dev": {
         "vimeo/psalm": "dev-master",

src/Psl/Internal/Loader.php

@@ -328,6 +328,20 @@ final class Loader
         'Psl\Password\hash',
         'Psl\Password\needs_rehash',
         'Psl\Password\verify',
+        'Psl\Str\Grapheme\contains',
+        'Psl\Str\Grapheme\contains_ci',
+        'Psl\Str\Grapheme\ends_with',
+        'Psl\Str\Grapheme\ends_with_ci',
+        'Psl\Str\Grapheme\length',
+        'Psl\Str\Grapheme\search',
+        'Psl\Str\Grapheme\search_ci',
+        'Psl\Str\Grapheme\search_last',
+        'Psl\Str\Grapheme\search_last_ci',
+        'Psl\Str\Grapheme\slice',
+        'Psl\Str\Grapheme\starts_with',
+        'Psl\Str\Grapheme\starts_with_ci',
+        'Psl\Str\Grapheme\strip_prefix',
+        'Psl\Str\Grapheme\strip_suffix',
     ];
 
     public const INTERFACES = [

src/Psl/Str/Grapheme/contains.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * Returns whether the 'haystack' string contains the 'needle' string.
+ *
+ * An optional offset determines where in the haystack the search begins. If the
+ * offset is negative, the search will begin that many characters from the end
+ * of the string. If the offset is out-of-bounds, a ViolationException will be
+ * thrown.
+ *
+ * @psalm-pure
+ *
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ */
+function contains(string $haystack, string $needle, int $offset = 0): bool
+{
+    if ('' === $needle) {
+        Psl\Internal\validate_offset($offset, length($haystack));
+
+        return true;
+    }
+
+    return null !== search($haystack, $needle, $offset);
+}

src/Psl/Str/Grapheme/contains_ci.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * Returns whether the 'haystack' string contains the 'needle' string.
+ *
+ * An optional offset determines where in the haystack the search begins. If the
+ * offset is negative, the search will begin that many characters from the end
+ * of the string. If the offset is out-of-bounds, a ViolationException will be
+ * thrown.
+ *
+ * @psalm-pure
+ *
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ */
+function contains_ci(string $haystack, string $needle, int $offset = 0): bool
+{
+    if ('' === $needle) {
+        Psl\Internal\validate_offset($offset, length($haystack));
+
+        return true;
+    }
+
+    return null !== search_ci($haystack, $needle, $offset);
+}

src/Psl/Str/Grapheme/ends_with.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * Returns whether the string ends with the given suffix.
+ *
+ * @psalm-pure
+ */
+function ends_with(string $string, string $suffix): bool
+{
+    if ($suffix === $string) {
+        return true;
+    }
+
+    $suffix_length = length($suffix);
+    $total_length  = length($string);
+    if ($suffix_length > $total_length) {
+        return false;
+    }
+
+    /** @psalm-suppress MissingThrowsDocblock */
+    $position = search_last($string, $suffix);
+    if (null === $position) {
+        return false;
+    }
+
+    return $position + $suffix_length === $total_length;
+}

src/Psl/Str/Grapheme/ends_with_ci.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * Returns whether the string ends with the given suffix (case-insensitive).
+ *
+ * @psalm-pure
+ */
+function ends_with_ci(string $string, string $suffix): bool
+{
+    if ($suffix === $string) {
+        return true;
+    }
+
+    $suffix_length = length($suffix);
+    $total_length  = length($string);
+    if ($suffix_length > $total_length) {
+        return false;
+    }
+
+    /** @psalm-suppress MissingThrowsDocblock */
+    $position = search_last_ci($string, $suffix);
+    if (null === $position) {
+        return false;
+    }
+
+    return $position + $suffix_length === $total_length;
+}

src/Psl/Str/Grapheme/length.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use function grapheme_strlen;
+
+/**
+ * Returns the length of the given string in grapheme units
+ *
+ * @psalm-pure
+ */
+function length(string $string): int
+{
+    return (int) grapheme_strlen($string);
+}

src/Psl/Str/Grapheme/search.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+use function grapheme_strpos;
+
+/**
+ * Returns the first position of the 'needle' string in the 'haystack' string
+ * grapheme units, or null if it isn't found.
+ *
+ * An optional offset determines where in the haystack the search begins. If the
+ * offset is negative, the search will begin that many characters from the end
+ * of the string.
+ *
+ * @psalm-pure
+ *
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ */
+function search(string $haystack, string $needle, int $offset = 0): ?int
+{
+    if ('' === $needle) {
+        return null;
+    }
+
+    $offset = Psl\Internal\validate_offset($offset, length($haystack));
+
+    return false === ($pos = grapheme_strpos($haystack, $needle, $offset)) ?
+        null :
+        $pos;
+}

src/Psl/Str/Grapheme/search_ci.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+use function grapheme_stripos;
+
+/**
+ * Returns the first position of the 'needle' string in the 'haystack' string,
+ * in grapheme units, or null if it isn't found (case-insensitive).
+ *
+ * An optional offset determines where in the haystack the search begins. If the
+ * offset is negative, the search will begin that many characters from the end
+ * of the string.
+ *
+ * @psalm-pure
+ *
+ * @throws Psl\Exception\InvariantViolationException If $offset is out-of-bounds.
+ */
+function search_ci(string $haystack, string $needle, int $offset = 0): ?int
+{
+    if ('' === $needle) {
+        return null;
+    }
+
+    $offset = Psl\Internal\validate_offset($offset, length($haystack));
+
+    return false === ($pos = grapheme_stripos($haystack, $needle, $offset)) ?
+        null :
+        $pos;
+}

src/Psl/Str/Grapheme/search_last.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+use function grapheme_strrpos;
+
+/**
+ * Returns the last position of the 'needle' string in the 'haystack' string,
+ * or null if it isn't found.
+ *
+ * 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.
+ *
+ * @psalm-pure
+ *
+ * @throws Psl\Exception\InvariantViolationException If the $offset is out-of-bounds.
+ */
+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 <= $haystack_length, 'Offset is out-of-bounds.');
+
+    return false === ($pos = grapheme_strrpos($haystack, $needle, $offset)) ?
+        null :
+        $pos;
+}

src/Psl/Str/Grapheme/search_last_ci.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+use function grapheme_strripos;
+
+/**
+ * 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.
+ *
+ * @psalm-pure
+ *
+ * @throws Psl\Exception\InvariantViolationException If the 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 = grapheme_strripos($haystack, $needle, $offset)) ?
+        null :
+        $pos;
+}

src/Psl/Str/Grapheme/slice.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+use Psl\Internal;
+
+use function mb_substr;
+
+/**
+ * Returns a substring of length `$length` of the given string starting at the
+ * `$offset`.
+ *
+ * If no length is given, the slice will contain the rest of the
+ * string. If the length is zero, the empty string will be returned. If the
+ * offset is out-of-bounds, an InvariantViolationException will be thrown.
+ *
+ * @psalm-pure
+ *
+ * @throws Psl\Exception\InvariantViolationException If a negative $length is given, or $offset is out-of-bounds.
+ */
+function slice(string $string, int $offset, ?int $length = null): string
+{
+    Psl\invariant(null === $length || $length >= 0, 'Expected a non-negative length.');
+    $string_length = length($string);
+    $offset        = Psl\Internal\validate_offset($offset, $string_length);
+
+    if (0 === $offset && (null === $length || $string_length <= $length)) {
+        return $string;
+    }
+
+    if (null === $length) {
+        return (string) grapheme_substr($string, $offset);
+    }
+
+    return (string) grapheme_substr($string, $offset, $length);
+}

src/Psl/Str/Grapheme/starts_with.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * Returns whether the string starts with the given prefix.
+ *
+ * @psalm-pure
+ */
+function starts_with(string $string, string $prefix): bool
+{
+    /** @psalm-suppress MissingThrowsDocblock */
+    return 0 === search($string, $prefix);
+}

src/Psl/Str/Grapheme/starts_with_ci.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Str\Grapheme;
+
+use Psl;
+
+/**
+ * Returns whether the string starts with the given prefix (case-insensitive).
+ *
+ * @psalm-pure
+ */
+function starts_with_ci(string $string, string $prefix): bool
+{
+    /** @psalm-suppress MissingThrowsDocblock */
+    return 0 === search_ci($string, $prefix);
+}