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AK: Add String{View,}::find(StringView)

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I personally mistook `find_first_of(StringView)` to be analogous to this
so let's add a `find()` method that actually searches the string.
This commit is contained in:
AnotherTest 2021-01-12 23:28:45 +03:30 • committed by Andreas Kling
parent 4fa8435310
commit 39442e6d4f
8 changed files with 70 additions and 11 deletions
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33
AK/MemMem.h
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@ -120,28 +120,39 @@ static inline Optional<size_t> memmem(const HaystackIterT& haystack_begin, const
return {};
}
static inline const void* memmem(const void* haystack, size_t haystack_length, const void* needle, size_t needle_length)
static inline Optional<size_t> memmem_optional(const void* haystack, size_t haystack_length, const void* needle, size_t needle_length)
{
if (needle_length == 0)
return haystack;
return 0;
if (haystack_length < needle_length)
return nullptr;
return {};
if (haystack_length == needle_length)
return __builtin_memcmp(haystack, needle, haystack_length) == 0 ? haystack : nullptr;
if (haystack_length == needle_length) {
if (__builtin_memcmp(haystack, needle, haystack_length) == 0)
return 0;
return {};
}
if (needle_length < 32)
return bitap_bitwise(haystack, haystack_length, needle, needle_length);
if (needle_length < 32) {
auto ptr = bitap_bitwise(haystack, haystack_length, needle, needle_length);
if (ptr)
return static_cast<size_t>((FlatPtr)ptr - (FlatPtr)haystack);
return {};
}
// Fallback to KMP.
Array<Span<const u8>, 1> spans { Span<const u8> { (const u8*)haystack, haystack_length } };
auto result = memmem(spans.begin(), spans.end(), { (const u8*)needle, needle_length });
return memmem(spans.begin(), spans.end(), { (const u8*)needle, needle_length });
}
if (result.has_value())
return (const u8*)haystack + result.value();
static inline const void* memmem(const void* haystack, size_t haystack_length, const void* needle, size_t needle_length)
{
auto offset = memmem_optional(haystack, haystack_length, needle, needle_length);
if (offset.has_value())
return ((const u8*)haystack) + offset.value();
return {};
return nullptr;
}
}