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omochimetaru 7/5/2018 6:43 AM
String.count https://github.com/apple/swift/blob/9286b3627d90523752cb1a2ffc02f7500ead0ea8/stdlib/public/core/StringRangeReplaceableCollection.swift#L82 String.distance(from:to:) https://github.com/apple/swift/blob/9286b3627d90523752cb1a2ffc02f7500ead0ea8/stdlib/public/core/StringRangeReplaceableCollection.swift#L233 _visistGuts(...) https://github.com/apple/swift/blob/dd20dfd8ee1c057923eda4c2d0a8106135d55c90/stdlib/public/core/StringGutsVisitor.swift#L213
apple/swift
swift - The Swift Programming Language
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apple/swift
swift - The Swift Programming Language
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apple/swift
swift - The Swift Programming Language
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6:44 AM
String._visit -> if _slowPath https://github.com/apple/swift/blob/dd20dfd8ee1c057923eda4c2d0a8106135d55c90/stdlib/public/core/StringGutsVisitor.swift#L30 String._visitOpaque https://github.com/apple/swift/blob/dd20dfd8ee1c057923eda4c2d0a8106135d55c90/stdlib/public/core/StringGutsVisitor.swift#L59 ここもさらにファストパスを全部さけると _UnmanagedOpaqueString : _StringVariant https://github.com/apple/swift/blob/084698da889de6ffc2a01bcc3c595c174096cebd/stdlib/public/core/UnmanagedOpaqueString.swift#L225
apple/swift
swift - The Swift Programming Language
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apple/swift
swift - The Swift Programming Language
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apple/swift
swift - The Swift Programming Language
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6:44 AM
_StringVariant.characterDistance https://github.com/apple/swift/blob/a4230ab2ad37e37edc9ed86cd1510b7c016a769d/stdlib/public/core/StringGraphemeBreaking.swift#L110
apple/swift
swift - The Swift Programming Language
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6:45 AM
で、たしかにO(n)で文字をstartからendまでイテレートしてた。
😂 1