mirror of
https://github.com/apple/swift.git
synced 2025-12-21 12:14:44 +01:00
54f4c77ce7
This property is too specific in that it forces a particular normalization; let's not expose it this way, but instead in the future with a full normalization API.
104 lines
3.9 KiB
Swift
104 lines
3.9 KiB
Swift
//===--- StringNormalization.swift ----------------------------------------===//
|
|
//
|
|
// This source file is part of the Swift.org open source project
|
|
//
|
|
// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
|
|
// Licensed under Apache License v2.0 with Runtime Library Exception
|
|
//
|
|
// See https://swift.org/LICENSE.txt for license information
|
|
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
import SwiftShims
|
|
|
|
// A namespace for various heuristics
|
|
//
|
|
internal enum _Normalization {
|
|
// ICU's NFC unorm2 instance
|
|
internal static var _nfcNormalizer: OpaquePointer = {
|
|
var err = __swift_stdlib_U_ZERO_ERROR
|
|
let normalizer = __swift_stdlib_unorm2_getNFCInstance(&err)
|
|
guard err.isSuccess else {
|
|
// This shouldn't be possible unless some deep (unrecoverable) system
|
|
// invariants are violated
|
|
fatalError("Unable to talk to ICU")
|
|
}
|
|
return normalizer
|
|
}()
|
|
|
|
// Whether this buffer of code units satisfies the quickCheck=YES property for
|
|
// normality checking under NFC.
|
|
//
|
|
// ICU provides a quickCheck, which may yield "YES", "NO", or "MAYBE". YES
|
|
// means that the string was determined to definitely be normal under NFC. In
|
|
// practice, the majority of Strings have this property. Checking for YES is
|
|
// considerably faster than trying to distinguish between NO and MAYBE.
|
|
internal static func _prenormalQuickCheckYes(
|
|
_ buffer: UnsafeBufferPointer<UInt16>
|
|
) -> Bool {
|
|
var err = __swift_stdlib_U_ZERO_ERROR
|
|
let length = __swift_stdlib_unorm2_spanQuickCheckYes(
|
|
_Normalization._nfcNormalizer,
|
|
buffer.baseAddress._unsafelyUnwrappedUnchecked,
|
|
Int32(buffer.count),
|
|
&err)
|
|
|
|
guard err.isSuccess else {
|
|
// This shouldn't be possible unless some deep (unrecoverable) system
|
|
// invariants are violated
|
|
fatalError("Unable to talk to ICU")
|
|
}
|
|
return length == buffer.count
|
|
}
|
|
internal static func _prenormalQuickCheckYes(
|
|
_ string: _UnmanagedString<UInt16>
|
|
) -> Bool {
|
|
var err = __swift_stdlib_U_ZERO_ERROR
|
|
let length = __swift_stdlib_unorm2_spanQuickCheckYes(
|
|
_Normalization._nfcNormalizer,
|
|
string.start,
|
|
Int32(string.count),
|
|
&err)
|
|
|
|
guard err.isSuccess else {
|
|
// This shouldn't be possible unless some deep (unrecoverable) system
|
|
// invariants are violated
|
|
fatalError("Unable to talk to ICU")
|
|
}
|
|
return length == string.count
|
|
}
|
|
}
|
|
|
|
extension UnicodeScalar {
|
|
// Normalization boundary - a place in a string where everything left of the
|
|
// boundary can be normalized independently from everything right of the
|
|
// boundary. The concatenation of each result is the same as if the entire
|
|
// string had been normalized as a whole.
|
|
//
|
|
// Normalization segment - a sequence of code units between two normalization
|
|
// boundaries (without any boundaries in the middle). Note that normalization
|
|
// segments can, as a process of normalization, expand, contract, and even
|
|
// produce new sub-segments.
|
|
|
|
// Whether this scalar value always has a normalization boundary before it.
|
|
internal var _hasNormalizationBoundaryBefore: Bool {
|
|
_sanityCheck(Int32(exactly: self.value) != nil, "top bit shouldn't be set")
|
|
let value = Int32(bitPattern: self.value)
|
|
return 0 != __swift_stdlib_unorm2_hasBoundaryBefore(
|
|
_Normalization._nfcNormalizer, value)
|
|
}
|
|
}
|
|
|
|
extension _Normalization {
|
|
// When normalized in NFC, some segments may expand in size (e.g. some non-BMP
|
|
// musical notes). This expansion is capped by the maximum expansion factor of
|
|
// the normal form. For NFC, that is 3x.
|
|
internal static let _maxNFCExpansionFactor = 3
|
|
|
|
// A small output buffer to use for normalizing a single normalization
|
|
// segment. Fits all but pathological arbitrary-length segments (i.e. zalgo-
|
|
// segments)
|
|
internal typealias _SegmentOutputBuffer = _FixedArray16<UInt16>
|
|
}
|