FloatingPointParsing.swift.gyb

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2019 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

%{

allFloatBits = [16, 32, 64, 80]

def floatName(bits):
    if bits == 16:
        return 'Float16'
    if bits == 32:
        return 'Float'
    if bits == 64:
        return 'Double'
    if bits == 80:
        return 'Float80'

cFuncSuffix2 = {16: 'f16', 32: 'f', 64: 'd', 80: 'ld'}

}%

/// Returns `true` if isspace(u) would return nonzero when the current
/// locale is the C locale; otherwise, returns false.
@inlinable // FIXME(sil-serialize-all)
internal func _isspace_clocale(_ u: UTF16.CodeUnit) -> Bool {
  return "\t\n\u{b}\u{c}\r ".utf16.contains(u)
}

% for bits in allFloatBits:
%   Self = floatName(bits)

% if bits == 80:
#if !(os(Windows) || os(Android)) && (arch(i386) || arch(x86_64))
% elif bits == 16:
#if !((os(macOS) || targetEnvironment(macCatalyst)) && arch(x86_64))
% end

%if bits == 16:
@available(SwiftStdlib 5.3, *)
%end
extension ${Self}: LosslessStringConvertible {
  /// Creates a new instance from the given string.
  ///
  /// The string passed as `text` can represent a real number in decimal or
  /// hexadecimal format or can be in a special format representing infinity
  /// or NaN ("not a number"). If `text` is not in a recognized format,
  /// the optional initializer will fail and return `nil`.
  ///
  /// The `text` string consists of an optional
  /// plus or minus sign character (`+` or `-`)
  /// followed by one of the following:
  ///
  /// - A *decimal string* contains a significand consisting of one
  ///   or more decimal digits that may include a decimal point:
  ///
  ///       let c = ${Self}("-1.0")
  ///       // c == -1.0
  ///
  ///       let d = ${Self}("28.375")
  ///       // d == 28.375
  ///
  ///   A decimal string may also include an exponent following the
  ///   significand, indicating the power of 10 by which the significand should
  ///   be multiplied. If included, the exponent is separated by a single
  ///   character, `e` or `E`, and consists of an optional plus or minus sign
  ///   character and a sequence of decimal digits.
  ///
  ///       let e = ${Self}("2837.5e-2")
  ///       // e == 28.375
  ///
  /// - A *hexadecimal string* contains a significand consisting of
  ///   `0X` or `0x` followed by one or more hexadecimal digits that may
  ///   include a decimal point.
  ///
  ///       let f = ${Self}("0x1c.6")
  ///       // f == 28.375
  ///
  ///   A hexadecimal string may also include an exponent
  ///   indicating the power of 2 by which the significand should
  ///   be multiplied. If included, the exponent is separated by a single
  ///   character, `p` or `P`, and consists of an optional plus or minus sign
  ///   character and a sequence of decimal digits.
  ///
  ///       let g = ${Self}("0x1.c6p4")
  ///       // g == 28.375
  ///
  /// - The input strings `"inf"` or `"infinity"` (case insensitive)
  ///   are converted to an infinite result:
  ///
  ///       let i = ${Self}("inf")
  ///       // i == ${Self}.infinity
  ///
  ///       let j = ${Self}("-Infinity")
  ///       // j == -${Self}.infinity
  ///
  /// - An input string of `"nan"` (case insensitive) is converted
  ///   into a *NaN* value:
  ///
  ///       let n = ${Self}("-nan")
  ///       // n?.isNaN == true
  ///       // n?.sign == .minus
  ///
  ///   A NaN string may also include a payload in parentheses following the
  ///   `"nan"` keyword. The payload consists of a sequence of decimal digits,
  ///   or the characters `0X` or `0x` followed by a sequence of hexadecimal
  ///   digits. If the payload contains any other characters, it is ignored.
  ///   If the value of the payload is larger than can be stored as the
  ///   payload of a `${Self}.nan`, the least significant bits are used.
  ///
  ///       let p = ${Self}("nan(0x10)")
  ///       // p?.isNaN == true
  ///       // String(p!) == "nan(0x10)"
  ///
  /// A string in any other format than those described above
  /// or containing additional characters
  /// results in a `nil` value. For example, the following conversions
  /// result in `nil`:
  ///
  ///       ${Self}(" 5.0")      // Includes whitespace
  ///       ${Self}("±2.0")      // Invalid character
  ///       ${Self}("0x1.25e4")  // Incorrect exponent format
  ///
  /// A decimal or hexadecimal string is converted to a `${Self}`
  /// instance using the IEEE 754 roundTiesToEven (default) rounding
  /// attribute.
  /// Values with absolute value smaller than `${Self}.leastNonzeroMagnitude`
  /// are rounded to plus or minus zero.
  /// Values with absolute value larger than `${Self}.greatestFiniteMagnitude`
  /// are rounded to plus or minus infinity.
  ///
  ///       let y = ${Self}("1.23e-9999")
  ///       // y == 0.0
  ///       // y?.sign == .plus
  ///
  ///       let z = ${Self}("-7.89e-7206")
  ///       // z == -0.0
  ///       // z?.sign == .minus
  ///
  ///       let r = ${Self}("1.23e17802")
  ///       // r == ${Self}.infinity
  ///
  ///       let s = ${Self}("-7.89e7206")
  ///       // s == ${Self}.-infinity
  ///
  /// - Note:  Prior to Swift 5.4, a decimal or
  /// hexadecimal input string whose value was too large to represent
  /// as a finite `${Self}` instance returned `nil` instead of
  /// `${Self}.infinity`.
  ///
  /// - Parameter text: An input string to convert to a `${Self}?` instance.
  ///
  @inlinable
  public init?<S: StringProtocol>(_ text: S) {
  %if bits == 16:
    self.init(Substring(text))
  %else:
    if #available(macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0, *) { //SwiftStdlib 5.3
      self.init(Substring(text))
    } else {
      self = 0.0
      let success = _withUnprotectedUnsafeMutablePointer(to: &self) { p -> Bool in
        text.withCString { chars -> Bool in
          switch chars[0] {
          case 9, 10, 11, 12, 13, 32:
            return false // Reject leading whitespace
          case 0:
            return false // Reject empty string
          default:
            break
          }
          let endPtr = _swift_stdlib_strto${cFuncSuffix2[bits]}_clocale(chars, p)
          // Succeed only if endPtr points to end of C string
          return endPtr != nil && endPtr![0] == 0
        }
      }
      if !success {
        return nil
      }
    }
  %end
  }

  // Caveat:  This implementation used to be inlineable.
  // In particular, we still have to export
  // _swift_stdlib_strtoXYZ_clocale()
  // as ABI to support old compiled code that still requires it.
  @available(SwiftStdlib 5.3, *)
  public init?(_ text: Substring) {
    self = 0.0
    let success = _withUnprotectedUnsafeMutablePointer(to: &self) { p -> Bool in
      text.withCString { chars -> Bool in
        switch chars[0] {
        case 9, 10, 11, 12, 13, 32:
          return false // Reject leading whitespace
        case 0:
          return false // Reject empty string
        default:
          break
        }
        let endPtr = _swift_stdlib_strto${cFuncSuffix2[bits]}_clocale(chars, p)
        // Succeed only if endPtr points to end of C string
        return endPtr != nil && endPtr![0] == 0
      }
    }
    if !success {
      return nil
    }
  }
}

% if bits in [16,80]:
#endif
% end

% end

// ${'Local Variables'}:
// eval: (read-only-mode 1)
// End: