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4ab45dfe20
This is a giant squashing of a lot of individual changes prototyping a switch of String in Swift 5 to be natively encoded as UTF-8. It includes what's necessary for a functional prototype, dropping some history, but still leaves plenty of history available for future commits. My apologies to anyone trying to do code archeology between this commit and the one prior. This was the lesser of evils.
72 lines
2.4 KiB
Swift
72 lines
2.4 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 - 2017 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 https://swift.org/LICENSE.txt for license information
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// See https://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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/// Returns a string read from standard input through the end of the current
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/// line or until EOF is reached.
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///
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/// Standard input is interpreted as `UTF-8`. Invalid bytes are replaced by
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/// Unicode [replacement characters][rc].
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///
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/// [rc]:
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/// https://unicode.org/glossary/#replacement_character
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///
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/// - Parameter strippingNewline: If `true`, newline characters and character
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/// combinations are stripped from the result; otherwise, newline characters
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/// or character combinations are preserved. The default is `true`.
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/// - Returns: The string of characters read from standard input. If EOF has
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/// already been reached when `readLine()` is called, the result is `nil`.
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public func readLine(strippingNewline: Bool = true) -> String? {
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var linePtrVar: UnsafeMutablePointer<UInt8>?
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var readBytes = swift_stdlib_readLine_stdin(&linePtrVar)
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if readBytes == -1 {
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return nil
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}
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_sanityCheck(readBytes >= 0,
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"unexpected return value from swift_stdlib_readLine_stdin")
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if readBytes == 0 {
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return ""
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}
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let linePtr = linePtrVar!
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if strippingNewline {
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// FIXME: Unicode conformance. To fix this, we need to reimplement the
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// code we call above to get a line, since it will only stop on LF.
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//
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// <rdar://problem/20013999> Recognize Unicode newlines in readLine()
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//
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// Recognize only LF and CR+LF combinations for now.
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let cr = UInt8(ascii: "\r")
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let lf = UInt8(ascii: "\n")
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if readBytes == 1 && linePtr[0] == lf {
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return ""
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}
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if readBytes >= 2 {
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switch (linePtr[readBytes - 2], linePtr[readBytes - 1]) {
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case (cr, lf):
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readBytes -= 2
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break
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case (_, lf):
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readBytes -= 1
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break
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default:
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()
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}
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}
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}
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let result = String._fromUTF8Repairing(
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UnsafeBufferPointer(start: linePtr, count: readBytes)).0
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_swift_stdlib_free(linePtr)
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return result
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}
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