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107 lines
3.5 KiB
Swift
107 lines
3.5 KiB
Swift
//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import SwiftShims
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#if _runtime(_ObjC)
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@_silgen_name("swift_stdlib_NSStringHashValue")
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func _stdlib_NSStringHashValue(_ str: AnyObject, _ isASCII: Bool) -> Int
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@_silgen_name("swift_stdlib_NSStringHashValuePointer")
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func _stdlib_NSStringHashValuePointer(_ str: OpaquePointer, _ isASCII: Bool) -> Int
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#endif
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extension _Unicode {
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internal static func hashASCII(
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_ string: UnsafeBufferPointer<UInt8>
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) -> Int {
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let collationTable = _swift_stdlib_unicode_getASCIICollationTable()
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var hasher = _SipHash13Context(key: _Hashing.secretKey)
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for c in string {
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_precondition(c <= 127)
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let element = collationTable[Int(c)]
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// Ignore zero valued collation elements. They don't participate in the
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// ordering relation.
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if element != 0 {
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hasher.append(element)
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}
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}
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return hasher._finalizeAndReturnIntHash()
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}
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internal static func hashUTF16(
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_ string: UnsafeBufferPointer<UInt16>
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) -> Int {
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let collationIterator = _swift_stdlib_unicodeCollationIterator_create(
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string.baseAddress!,
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UInt32(string.count))
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defer { _swift_stdlib_unicodeCollationIterator_delete(collationIterator) }
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var hasher = _SipHash13Context(key: _Hashing.secretKey)
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while true {
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var hitEnd = false
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let element =
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_swift_stdlib_unicodeCollationIterator_next(collationIterator, &hitEnd)
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if hitEnd {
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break
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}
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// Ignore zero valued collation elements. They don't participate in the
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// ordering relation.
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if element != 0 {
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hasher.append(element)
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}
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}
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return hasher._finalizeAndReturnIntHash()
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}
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}
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extension String : Hashable {
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/// The string's hash value.
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///
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/// Hash values are not guaranteed to be equal across different executions of
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/// your program. Do not save hash values to use during a future execution.
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public var hashValue: Int {
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#if _runtime(_ObjC)
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// Mix random bits into NSString's hash so that clients don't rely on
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// Swift.String.hashValue and NSString.hash being the same.
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#if arch(i386) || arch(arm)
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let hashOffset = Int(bitPattern: 0x88dd_cc21)
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#else
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let hashOffset = Int(bitPattern: 0x429b_1266_88dd_cc21)
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#endif
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// If we have a contiguous string then we can use the stack optimization.
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let core = self._core
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let isASCII = core.isASCII
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if core.hasContiguousStorage {
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let stackAllocated = _NSContiguousString(core)
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return hashOffset ^ stackAllocated._unsafeWithNotEscapedSelfPointer {
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return _stdlib_NSStringHashValuePointer($0, isASCII)
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}
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} else {
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let cocoaString = unsafeBitCast(
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self._bridgeToObjectiveCImpl(), to: _NSStringCore.self)
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return hashOffset ^ _stdlib_NSStringHashValue(cocoaString, isASCII)
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}
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#else
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if let asciiBuffer = self._core.asciiBuffer {
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return _Unicode.hashASCII(UnsafeBufferPointer(
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start: asciiBuffer.baseAddress!,
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count: asciiBuffer.count))
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} else {
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return _Unicode.hashUTF16(
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UnsafeBufferPointer(start: _core.startUTF16, count: _core.count))
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}
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#endif
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}
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}
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