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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift Collections open source project
//
// Copyright (c) 2023 - 2024 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
//
//===----------------------------------------------------------------------===//
#if swift(>=5.8)
@available(macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4, *)
extension BigString._Chunk {
mutating func append(_ other: __owned Self) {
self._append(other.string[...], other.counts)
}
mutating func append(from ingester: inout BigString._Ingester) -> Self? {
let desired = BigString._Ingester.desiredNextChunkSize(
remaining: self.utf8Count + ingester.remainingUTF8)
if desired == self.utf8Count {
return nil
}
if desired > self.utf8Count {
if let slice = ingester.nextSlice(maxUTF8Count: desired - self.utf8Count) {
self._append(slice)
}
return nil
}
// Split current chunk.
let cut = string.unicodeScalars._index(roundingDown: string._utf8Index(at: desired))
var new = self.split(at: cut)
precondition(!self.isUndersized)
let slice = ingester.nextSlice()!
new._append(slice)
precondition(ingester.isAtEnd)
precondition(!new.isUndersized)
return new
}
mutating func _append(_ other: Slice) {
let c = Counts(other)
_append(other.string, c)
}
mutating func _append(_ str: __owned Substring, _ other: Counts) {
self.counts.append(other)
self.string += str
invariantCheck()
}
mutating func _prepend(_ other: Slice) {
let c = Counts(other)
_prepend(other.string, c)
}
mutating func _prepend(_ str: __owned Substring, _ other: Counts) {
let c = self.counts
self.counts = other
self.counts.append(c)
self.string = str + self.string
invariantCheck()
}
}
@available(macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4, *)
extension BigString._Chunk {
mutating func _insert(
_ slice: Slice,
at index: String.Index,
old: inout _CharacterRecognizer,
new: inout _CharacterRecognizer
) -> String.Index? {
let offset = string._utf8Offset(of: index)
let count = slice.string.utf8.count
precondition(utf8Count + count <= Self.maxUTF8Count)
let parts = self.splitCounts(at: index)
self.counts = parts.left
self.counts.append(Counts(slice))
self.counts.append(parts.right)
string.insert(contentsOf: slice.string, at: index)
let end = string._utf8Index(at: offset + count)
return resyncBreaks(startingAt: end, old: &old, new: &new)
}
typealias States = (increment: Int, old: _CharacterRecognizer, new: _CharacterRecognizer)
mutating func insertAll(
from ingester: inout BigString._Ingester,
at index: String.Index
) -> States? {
let remaining = ingester.remainingUTF8
precondition(self.utf8Count + remaining <= Self.maxUTF8Count)
var startState = ingester.state
guard let slice = ingester.nextSlice(maxUTF8Count: remaining) else { return nil }
var endState = ingester.state
assert(ingester.isAtEnd)
let offset = string._utf8Offset(of: index)
if let _ = self._insert(slice, at: index, old: &startState, new: &endState) {
return nil
}
return (self.utf8Count - offset, startState, endState)
}
enum InsertResult {
case inline(States?)
case split(spawn: BigString._Chunk, endStates: States?)
case large
}
mutating func insert(
from ingester: inout BigString._Ingester,
at index: String.Index
) -> InsertResult {
let origCount = self.utf8Count
let rem = ingester.remainingUTF8
guard rem > 0 else { return .inline(nil) }
let sum = origCount + rem
let offset = string._utf8Offset(of: index)
if sum <= Self.maxUTF8Count {
let r = insertAll(from: &ingester, at: index)
return .inline(r)
}
let desired = BigString._Ingester.desiredNextChunkSize(remaining: sum)
guard sum - desired + Self.maxSlicingError <= Self.maxUTF8Count else { return .large }
if desired <= offset {
// Inserted text lies entirely within `spawn`.
let cut = string.unicodeScalars._index(roundingDown: string._utf8Index(at: desired))
var spawn = split(at: cut)
let i = spawn.string._utf8Index(at: offset - self.utf8Count)
let r = spawn.insertAll(from: &ingester, at: i)
assert(r == nil || r?.increment == sum - offset)
return .split(spawn: spawn, endStates: r)
}
if desired >= offset + rem {
// Inserted text lies entirely within `self`.
let cut = string.unicodeScalars._index(roundingDown: string._utf8Index(at: desired - rem))
assert(cut >= index)
var spawn = split(at: cut)
guard
var r = self.insertAll(from: &ingester, at: string._utf8Index(at: offset)),
nil == spawn.resyncBreaks(startingAt: spawn.string.startIndex, old: &r.old, new: &r.new)
else {
return .split(spawn: spawn, endStates: nil)
}
return .split(spawn: spawn, endStates: (sum - offset, r.old, r.new))
}
// Inserted text is split across `self` and `spawn`.
var spawn = split(at: index)
var old = ingester.state
if let slice = ingester.nextSlice(maxUTF8Count: desired - offset) {
self._append(slice)
}
let slice = ingester.nextSlice()!
assert(ingester.isAtEnd)
var new = ingester.state
let stop = spawn._insert(slice, at: spawn.string.startIndex, old: &old, new: &new)
if stop != nil {
return .split(spawn: spawn, endStates: nil)
}
return .split(spawn: spawn, endStates: (sum - offset, old, new))
}
}
#endif
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