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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2020-2023 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
//
//===----------------------------------------------------------------------===//
#if FOUNDATION_FRAMEWORK
@_spi(Unstable) internal import CollectionsInternal
#elseif canImport(_RopeModule)
internal import _RopeModule
#elseif canImport(_FoundationCollections)
internal import _FoundationCollections
#endif
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString {
public struct Runs: Sendable {
internal typealias _InternalRun = AttributedString._InternalRun
internal typealias _AttributeStorage = AttributedString._AttributeStorage
internal typealias _InternalRuns = AttributedString._InternalRuns
internal typealias AttributeRunBoundaries = AttributedString.AttributeRunBoundaries
internal var _guts: Guts
internal var _bounds: Range<Index>
internal var _strBounds: Range<BigString.Index>
internal init(_ guts: Guts, in bounds: Range<BigString.Index>) {
_guts = guts
let stringLowerBound = _guts.string.unicodeScalars.index(roundingDown: bounds.lowerBound)
let stringUpperBound = _guts.string.unicodeScalars.index(roundingDown: bounds.upperBound)
_strBounds = stringLowerBound ..< stringUpperBound
let lower = _guts.findRun(at: _strBounds.lowerBound)
let start = Index(_runIndex: lower.runIndex, stringIndex: lower.start)
let end: Index
if _strBounds.upperBound == _guts.string.endIndex {
end = Index(
_runOffset: _guts.runs.count,
runIndex: _guts.runs.endIndex.base,
stringIndex: _strBounds.upperBound)
} else if _strBounds.upperBound == _guts.string.startIndex {
assert(stringLowerBound == stringUpperBound)
end = start
} else {
let last = _guts.runs.index(atUTF8Offset: _strBounds.upperBound.utf8Offset - 1).index
let next = _guts.runs.index(after: last)
let stringEnd = _guts.string.utf8.index(
_strBounds.upperBound,
offsetBy: next.utf8Offset - _strBounds.upperBound.utf8Offset)
end = Index(_runIndex: next, stringIndex: stringEnd)
}
assert(start._runIndex != nil && start._stringIndex != nil)
assert(end._runIndex != nil && end._stringIndex != nil)
assert(start._stringIndex!.utf8Offset <= _strBounds.lowerBound.utf8Offset)
assert(end._stringIndex!.utf8Offset >= _strBounds.upperBound.utf8Offset)
self._bounds = start ..< end
}
}
public var runs: Runs {
Runs(_guts, in: _guts.string.startIndex ..< _guts.string.endIndex)
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString.Runs: Equatable {
public static func == (lhs: Self, rhs: Self) -> Bool {
// Note: Unlike AttributedString itself, this is comparing run lengths without normalizing
// the underlying characters.
//
// I.e., the runs of two equal attribute strings may or may not compare equal.
// Shortcut: compare overall UTF-8 counts.
let leftUTF8Count = lhs._strBounds._utf8OffsetRange.count
let rightUTF8Count = rhs._strBounds._utf8OffsetRange.count
guard leftUTF8Count == rightUTF8Count else { return false }
// Shortcut: compare run counts.
let leftRunCount = lhs._bounds.upperBound._runOffset - lhs._bounds.lowerBound._runOffset
let rightRunCount = rhs._bounds.upperBound._runOffset - rhs._bounds.lowerBound._runOffset
guard leftRunCount == rightRunCount else { return false }
return lhs.elementsEqual(rhs)
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString.Runs: CustomStringConvertible {
public var description: String {
_guts.description(in: _strBounds)
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString.Runs {
public struct Index: Sendable {
/// The offset of this run from the start of the attributed string.
/// This is always set to a valid value.
internal var _runOffset: Int
/// The underlying index in the rope.
///
/// This may be nil if the index was advanced without going through the Collection APIs;
/// in that case, the index can be restored using the offset, although
/// at a log(count) cost.
internal var _runIndex: _InternalRuns.Storage.Index?
/// The position in string storage corresponding to the start of this run.
/// This may be outside of the bounds of the `Runs` if this is addressing the first run.
/// (I.e., this is the unsliced, global start of the run.)
///
/// This may be nil if the index was advanced without going through the Collection APIs;
/// in that case, the index can be restored using the offset, although
/// at a log(count) cost.
internal var _stringIndex: BigString.Index?
internal init(_runOffset: Int) {
self._runOffset = _runOffset
self._runIndex = nil
self._stringIndex = nil
}
internal init(_runOffset: Int, runIndex: _InternalRuns.Storage.Index, stringIndex: BigString.Index) {
self._runOffset = _runOffset
self._runIndex = runIndex
self._stringIndex = stringIndex
}
internal init(_runIndex: _InternalRuns.Index, stringIndex: BigString.Index) {
self._runOffset = _runIndex.offset
self._runIndex = _runIndex.base
self._stringIndex = stringIndex
}
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString.Runs.Index: Comparable {
public static func == (lhs: Self, rhs: Self) -> Bool {
lhs._runOffset == rhs._runOffset
}
public static func < (lhs: Self, rhs: Self) -> Bool {
lhs._runOffset < rhs._runOffset
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString.Runs.Index: Strideable {
// FIXME: `Index` conforming to `Strideable` was an unfortunate choice.
// It means we lose direct rope indices whenever someone advances a standalone index,
// slowing down subsequent access.
public func distance(to other: Self) -> Int {
other._runOffset - self._runOffset
}
public func advanced(by n: Int) -> Self {
Self(_runOffset: self._runOffset + n)
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension Range<AttributedString.Runs.Index> {
var _runOffsetRange: Range<Int> {
Range<Int>(uncheckedBounds: (lowerBound._runOffset, upperBound._runOffset))
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString.Runs: BidirectionalCollection {
public typealias Element = Run
internal func _resolveRun(_ i: Index) -> _InternalRuns.Index {
precondition(i >= _bounds.lowerBound && i <= _bounds.upperBound, "Index out of bounds")
guard let ri = i._runIndex, _guts.runs._rope.isValid(ri) else {
return _guts.runs.index(atRunOffset: i._runOffset)
}
let utf8Offset = (
i._stringIndex.map { $0.utf8Offset }
?? _guts.runs._rope.offset(of: ri, in: _InternalRuns.UTF8Metric()))
return _InternalRuns.Index(ri, offset: i._runOffset, utf8Offset: utf8Offset)
}
internal func _resolve(_ i: Index) -> (runIndex: _InternalRuns.Index, start: BigString.Index) {
let runIndex = _resolveRun(i)
var start: BigString.Index
if let si = i._stringIndex, si.utf8Offset == runIndex.utf8Offset {
// Don't trust that the string index is still valid. Let BigString resolve it.
start = _guts.string.utf8.index(roundingDown: si)
} else {
start = _guts.utf8Index(at: runIndex.utf8Offset)
}
return (runIndex, start)
}
public var startIndex: Index {
_bounds.lowerBound
}
public var endIndex: Index {
_bounds.upperBound
}
public func index(after i: Index) -> Index {
precondition(i >= _bounds.lowerBound, "AttributedString.Runs index out of bounds")
precondition(i < _bounds.upperBound, "Can't advance AttributedString.Runs index beyond end")
let next = _guts.runs.index(after: _resolveRun(i))
let stringIndex = (
i._stringIndex.map { _guts.string.utf8.index($0, offsetBy: next.utf8Offset - $0.utf8Offset) }
?? _guts.utf8Index(at: next.utf8Offset))
return Index(_runIndex: next, stringIndex: stringIndex)
}
public func index(before i: Index) -> Index {
precondition(i > _bounds.lowerBound, "Can't step AttributedString.Runs index below start")
let prev = _guts.runs.index(before: _resolveRun(i))
let stringIndex = (
i._stringIndex.map { _guts.string.utf8.index($0, offsetBy: prev.utf8Offset - $0.utf8Offset) }
?? _guts.utf8Index(at: prev.utf8Offset))
return Index(_runIndex: prev, stringIndex: stringIndex)
}
@_alwaysEmitIntoClient
public func distance(from start: Index, to end: Index) -> Int {
start.distance(to: end)
}
@_alwaysEmitIntoClient
public func index(_ i: Index, offsetBy distance: Int) -> Index {
#if FOUNDATION_FRAMEWORK
if #available(macOS 14, iOS 17, tvOS 17, watchOS 10, *) {
return _index(i, offsetBy: distance)
}
#endif
return i.advanced(by: distance)
}
@available(FoundationPreview 0.1, *)
@usableFromInline
internal func _index(_ index: Index, offsetBy distance: Int) -> Index {
let i = _guts.runs.index(_resolveRun(index), offsetBy: distance)
// Note: bounds checking of result is delayed until subscript.
let stringIndex = (
index._stringIndex.map { _guts.string.utf8.index($0, offsetBy: i.utf8Offset - $0.utf8Offset) }
?? _guts.utf8Index(at: i.utf8Offset))
return Index(_runIndex: i, stringIndex: stringIndex)
}
@_alwaysEmitIntoClient
public func index(_ i: Index, offsetBy distance: Int, limitedBy limit: Index) -> Index? {
// This is the stdlib's default implementation for RandomAccessCollection types.
// (It's _far_ more efficient than the O(n) algorithm that used to apply here by default,
// in both the original and the tree-based representation.)
let l = self.distance(from: i, to: limit)
if distance > 0 ? l >= 0 && l < distance : l <= 0 && distance < l {
return nil
}
return index(i, offsetBy: distance)
}
public subscript(position: Index) -> Run {
precondition(_bounds.contains(position), "AttributedString.Runs index is out of bounds")
return self[_unchecked: _resolve(position)]
}
public subscript(position: AttributedString.Index) -> Run {
precondition(
_strBounds.contains(position._value),
"AttributedString index is out of bounds")
let r = _guts.findRun(at: position._value)
return self[_unchecked: r]
}
internal subscript(_unchecked i: (runIndex: _InternalRuns.Index, start: BigString.Index)) -> Run {
let run = _guts.runs[i.runIndex]
// Clamp the run into the bounds of self, using relative calculations.
let lowerBound = Swift.max(i.start, _strBounds.lowerBound)
let upperUTF8 = Swift.min(i.start.utf8Offset + run.length, _strBounds.upperBound.utf8Offset)
let upperBound = _guts.string.utf8.index(lowerBound, offsetBy: upperUTF8 - lowerBound.utf8Offset)
return Run(_attributes: run.attributes, lowerBound ..< upperBound, _guts)
}
internal subscript(internal position: Index) -> _InternalRun {
let i = _resolveRun(position)
return _guts.runs[i]
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString.Runs {
// FIXME: Make public, with a better name. (Probably no need to state "run" -- `index(containing:)`?)
internal func indexOfRun(at position: AttributedString.Index) -> Index {
precondition(
position._value >= _strBounds.lowerBound && position._value <= _strBounds.upperBound,
"AttributedString index is out of bounds")
let r = _guts.findRun(at: position._value)
return Index(_runIndex: r.runIndex, stringIndex: r.start)
}
internal func _firstOfMatchingRuns(
with i: _InternalRuns.Index,
comparing attributeNames: [String]
) -> _InternalRuns.Index {
precondition(!attributeNames.isEmpty)
let attributes = _guts.runs[i].attributes
var j = i
while j.offset > startIndex._runOffset {
let prev = _guts.runs.index(before: j)
let a = _guts.runs[prev].attributes
if !attributes.isEqual(to: a, comparing: attributeNames) {
return j
}
j = prev
}
return j
}
internal func _lastOfMatchingRuns(
with i: _InternalRuns.Index,
comparing attributeNames: [String]
) -> _InternalRuns.Index {
precondition(!attributeNames.isEmpty)
precondition(i.offset < endIndex._runOffset)
let attributes = _guts.runs[i].attributes
var j = i
while true {
let next = _guts.runs.index(after: j)
if next.offset == endIndex._runOffset { break }
let a = _guts.runs[next].attributes
if !attributes.isEqual(to: a, comparing: attributeNames) {
return j
}
j = next
}
return j
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension AttributedString.Runs {
internal func _slicedRunBoundary(
after i: AttributedString.Index,
attributeNames: [String],
constraints: [AttributeRunBoundaries]
) -> AttributedString.Index {
precondition(
self._strBounds.contains(i._value),
"AttributedString index is out of bounds")
precondition(!attributeNames.isEmpty)
let r = _guts.findRun(at: i._value)
let endRun = _lastOfMatchingRuns(with: r.runIndex, comparing: attributeNames)
let utf8End = endRun.utf8Offset + _guts.runs[endRun].length
let stringEnd = Swift.min(
_guts.string.utf8.index(r.start, offsetBy: utf8End - r.start.utf8Offset),
_strBounds.upperBound)
return .init(_guts.string._firstConstraintBreak(in: i._value ..< stringEnd, with: constraints))
}
internal func _slicedRunBoundary(
before i: AttributedString.Index,
attributeNames: [String],
constraints: [AttributeRunBoundaries]
) -> AttributedString.Index {
precondition(
i._value > self._strBounds.lowerBound && i._value <= self._strBounds.upperBound,
"AttributedString index is out of bounds")
precondition(!attributeNames.isEmpty)
let r = _guts.runs.index(atUTF8Offset: i._value.utf8Offset - 1)
let startRun = _firstOfMatchingRuns(with: r.index, comparing: attributeNames)
let stringStart = Swift.max(
_guts.string.utf8.index(i._value, offsetBy: startRun.utf8Offset - i._value.utf8Offset),
_strBounds.lowerBound)
return .init(_guts.string._lastConstraintBreak(in: stringStart ..< i._value, with: constraints))
}
internal func _slicedRunBoundary(
roundingDown i: AttributedString.Index,
attributeNames: [String],
constraints: [AttributeRunBoundaries]
) -> (index: AttributedString.Index, runIndex: AttributedString._InternalRuns.Index) {
precondition(
i._value >= self._strBounds.lowerBound && i._value <= self._strBounds.upperBound,
"AttributedString index is out of bounds")
precondition(!attributeNames.isEmpty)
let r = _guts.findRun(at: i._value)
if r.runIndex.offset == endIndex._runOffset {
return (i, r.runIndex)
}
let startRun = _firstOfMatchingRuns(with: r.runIndex, comparing: attributeNames)
let stringStart = Swift.max(
_guts.string.utf8.index(r.start, offsetBy: startRun.utf8Offset - r.start.utf8Offset),
_strBounds.lowerBound)
let j = _guts.string.unicodeScalars.index(after: i._value)
let last = _guts.string._lastConstraintBreak(in: stringStart ..< j, with: constraints)
return (.init(last), r.runIndex)
}
}
@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
extension BigString {
internal func _firstConstraintBreak(
in range: Range<Index>,
with constraints: [AttributedString.AttributeRunBoundaries]
) -> Index {
guard !constraints.isEmpty, !range.isEmpty else { return range.upperBound }
var r = range
if
constraints.contains(.paragraph),
let firstBreak = self._findFirstParagraphBoundary(in: r)
{
r = r.lowerBound ..< firstBreak
}
if constraints._containsScalarConstraint {
// Note: we need to slice runs on matching scalars even if they don't carry
// the attributes we're looking for.
let scalars: [UnicodeScalar] = constraints.compactMap { $0._constrainedScalar }
if let firstBreak = self.unicodeScalars[r]._findFirstScalarBoundary(for: scalars) {
r = r.lowerBound ..< firstBreak
}
}
return r.upperBound
}
internal func _lastConstraintBreak(
in range: Range<Index>,
with constraints: [AttributedString.AttributeRunBoundaries]
) -> Index {
guard !constraints.isEmpty, !range.isEmpty else { return range.lowerBound }
var r = range
if
constraints.contains(.paragraph),
let lastBreak = self._findLastParagraphBoundary(in: r)
{
r = lastBreak ..< r.upperBound
}
if constraints._containsScalarConstraint {
// Note: we need to slice runs on matching scalars even if they don't carry
// the attributes we're looking for.
let scalars: [UnicodeScalar] = constraints.compactMap { $0._constrainedScalar }
if let lastBreak = self.unicodeScalars[r]._findLastScalarBoundary(for: scalars) {
r = lastBreak ..< r.upperBound
}
}
return r.lowerBound
}
internal func _findFirstParagraphBoundary(in range: Range<Index>) -> Index? {
self.utf8[range]._getBlock(for: [.findEnd], in: range.lowerBound ..< range.lowerBound).end
}
internal func _findLastParagraphBoundary(in range: Range<Index>) -> Index? {
guard range.upperBound > startIndex else { return nil }
let lower = self.utf8.index(before: range.upperBound)
return self.utf8[range]._getBlock(for: [.findStart], in: lower ..< range.upperBound).start
}
}
extension BigSubstring.UnicodeScalarView {
internal func _findFirstScalarBoundary(for scalars: [UnicodeScalar]) -> Index? {
var i = self.startIndex
guard i < self.endIndex else { return nil }
if scalars.contains(self[i]) {
return self.index(after: i)
}
while true {
self.formIndex(after: &i)
guard i < self.endIndex else { break }
if scalars.contains(self[i]) {
return i
}
}
return nil
}
internal func _findLastScalarBoundary(for scalars: [UnicodeScalar]) -> Index? {
guard !isEmpty else { return nil }
var i = self.index(before: self.endIndex)
if scalars.contains(self[i]) {
return i
}
while i > self.startIndex {
let j = self.index(before: i)
if scalars.contains(self[j]) {
return i
}
i = j
}
return nil
}
}
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