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StringIndexValidation.swift
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StringIndexValidation.swift
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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 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
//
//===----------------------------------------------------------------------===//
// Index validation
extension _StringGuts {
@_alwaysEmitIntoClient @inline(__always)
internal func isFastScalarIndex(_ i: String.Index) -> Bool {
hasMatchingEncoding(i) && i._isScalarAligned
}
@_alwaysEmitIntoClient @inline(__always)
internal func isFastCharacterIndex(_ i: String.Index) -> Bool {
hasMatchingEncoding(i) && i._isCharacterAligned
}
}
// Subscalar index validation (UTF-8 & UTF-16 views)
extension _StringGuts {
@_alwaysEmitIntoClient
internal func validateSubscalarIndex(_ i: String.Index) -> String.Index {
let i = ensureMatchingEncoding(i)
_precondition(i._encodedOffset < count, "String index is out of bounds")
return i
}
@_alwaysEmitIntoClient
internal func validateSubscalarIndex(
_ i: String.Index,
in bounds: Range<String.Index>
) -> String.Index {
_internalInvariant(bounds.upperBound <= endIndex)
let i = ensureMatchingEncoding(i)
_precondition(i >= bounds.lowerBound && i < bounds.upperBound,
"Substring index is out of bounds")
return i
}
@_alwaysEmitIntoClient
internal func validateInclusiveSubscalarIndex(
_ i: String.Index
) -> String.Index {
let i = ensureMatchingEncoding(i)
_precondition(i._encodedOffset <= count, "String index is out of bounds")
return i
}
@_alwaysEmitIntoClient
internal func validateInclusiveSubscalarIndex(
_ i: String.Index,
in bounds: Range<String.Index>
) -> String.Index {
_internalInvariant(bounds.upperBound <= endIndex)
let i = ensureMatchingEncoding(i)
_precondition(i >= bounds.lowerBound && i <= bounds.upperBound,
"Substring index is out of bounds")
return i
}
@_alwaysEmitIntoClient
internal func validateSubscalarRange(
_ range: Range<String.Index>
) -> Range<String.Index> {
let upper = ensureMatchingEncoding(range.upperBound)
let lower = ensureMatchingEncoding(range.lowerBound)
// Note: if only `lower` was miscoded, then the range invariant `lower <=
// upper` may no longer hold after the above conversions, so we need to
// re-check it here.
_precondition(upper <= endIndex && lower <= upper,
"String index range is out of bounds")
return Range(_uncheckedBounds: (lower, upper))
}
@_alwaysEmitIntoClient
internal func validateSubscalarRange(
_ range: Range<String.Index>,
in bounds: Range<String.Index>
) -> Range<String.Index> {
_internalInvariant(bounds.upperBound <= endIndex)
let upper = ensureMatchingEncoding(range.upperBound)
let lower = ensureMatchingEncoding(range.lowerBound)
// Note: if only `lower` was miscoded, then the range invariant `lower <=
// upper` may no longer hold after the above conversions, so we need to
// re-check it here.
_precondition(
lower >= bounds.lowerBound
&& lower <= upper
&& upper <= bounds.upperBound,
"Substring index range is out of bounds")
return Range(_uncheckedBounds: (lower, upper))
}
}
// Scalar index validation (Unicode scalar views)
extension _StringGuts {
/// Validate `i` and adjust its position toward the start, returning the
/// resulting index or trapping as appropriate. If this function returns, then
/// the returned value
///
/// - has an encoding that matches this string,
/// - is within the bounds of this string, and
/// - is aligned on a scalar boundary.
@_alwaysEmitIntoClient
internal func validateScalarIndex(_ i: String.Index) -> String.Index {
if isFastScalarIndex(i) {
_precondition(i._encodedOffset < count, "String index is out of bounds")
return i
}
return scalarAlign(validateSubscalarIndex(i))
}
/// Validate `i` and adjust its position toward the start, returning the
/// resulting index or trapping as appropriate. If this function returns, then
/// the returned value
///
/// - has an encoding that matches this string,
/// - is within `start ..< end`, and
/// - is aligned on a scalar boundary.
@_alwaysEmitIntoClient
internal func validateScalarIndex(
_ i: String.Index,
in bounds: Range<String.Index>
) -> String.Index {
_internalInvariant(bounds.upperBound <= endIndex)
if isFastScalarIndex(i) {
_precondition(i >= bounds.lowerBound && i < bounds.upperBound,
"Substring index is out of bounds")
return i
}
return scalarAlign(validateSubscalarIndex(i, in: bounds))
}
}
extension _StringGuts {
/// Validate `i` and adjust its position toward the start, returning the
/// resulting index or trapping as appropriate. If this function returns, then
/// the returned value
///
/// - has an encoding that matches this string,
/// - is within the bounds of this string (including the `endIndex`), and
/// - is aligned on a scalar boundary.
@_alwaysEmitIntoClient
internal func validateInclusiveScalarIndex(
_ i: String.Index
) -> String.Index {
if isFastScalarIndex(i) {
_precondition(i._encodedOffset <= count, "String index is out of bounds")
return i
}
return scalarAlign(validateInclusiveSubscalarIndex(i))
}
/// Validate `i` and adjust its position toward the start, returning the
/// resulting index or trapping as appropriate. If this function returns, then
/// the returned value
///
/// - has an encoding that matches this string,
/// - is within the bounds of this string (including the `endIndex`), and
/// - is aligned on a scalar boundary.
@_alwaysEmitIntoClient
internal func validateInclusiveScalarIndex(
_ i: String.Index,
in bounds: Range<String.Index>
) -> String.Index {
_internalInvariant(bounds.upperBound <= endIndex)
if isFastScalarIndex(i) {
_precondition(i >= bounds.lowerBound && i <= bounds.upperBound,
"Substring index is out of bounds")
return i
}
return scalarAlign(validateInclusiveSubscalarIndex(i, in: bounds))
}
}
extension _StringGuts {
/// Validate `range` and adjust the position of its bounds, returning the
/// resulting range or trapping as appropriate. If this function returns, then
/// the bounds of the returned value
///
/// - have an encoding that matches this string,
/// - are within the bounds of this string, and
/// - are aligned on a scalar boundary.
internal func validateScalarRange(
_ range: Range<String.Index>
) -> Range<String.Index> {
if
isFastScalarIndex(range.lowerBound), isFastScalarIndex(range.upperBound)
{
_precondition(range.upperBound._encodedOffset <= count,
"String index range is out of bounds")
return range
}
let r = validateSubscalarRange(range)
return Range(
_uncheckedBounds: (scalarAlign(r.lowerBound), scalarAlign(r.upperBound)))
}
/// Validate `range` and adjust the position of its bounds, returning the
/// resulting range or trapping as appropriate. If this function returns, then
/// the bounds of the returned value
///
/// - have an encoding that matches this string,
/// - are within `start ..< end`, and
/// - are aligned on a scalar boundary.
internal func validateScalarRange(
_ range: Range<String.Index>,
in bounds: Range<String.Index>
) -> Range<String.Index> {
_internalInvariant(bounds.upperBound <= endIndex)
if
isFastScalarIndex(range.lowerBound), isFastScalarIndex(range.upperBound)
{
_precondition(
range.lowerBound >= bounds.lowerBound
&& range.upperBound <= bounds.upperBound,
"String index range is out of bounds")
return range
}
let r = validateSubscalarRange(range, in: bounds)
let upper = scalarAlign(r.upperBound)
let lower = scalarAlign(r.lowerBound)
return Range(_uncheckedBounds: (lower, upper))
}
}
// Character index validation (String & Substring)
extension _StringGuts {
internal func validateCharacterIndex(_ i: String.Index) -> String.Index {
if isFastCharacterIndex(i) {
_precondition(i._encodedOffset < count, "String index is out of bounds")
return i
}
return roundDownToNearestCharacter(scalarAlign(validateSubscalarIndex(i)))
}
internal func validateCharacterIndex(
_ i: String.Index,
in bounds: Range<String.Index>
) -> String.Index {
_internalInvariant(bounds.upperBound <= endIndex)
if isFastCharacterIndex(i) {
_precondition(i >= bounds.lowerBound && i < bounds.upperBound,
"Substring index is out of bounds")
return i
}
return roundDownToNearestCharacter(
scalarAlign(validateSubscalarIndex(i, in: bounds)),
in: bounds)
}
internal func validateInclusiveCharacterIndex(
_ i: String.Index
) -> String.Index {
if isFastCharacterIndex(i) {
_precondition(i._encodedOffset <= count, "String index is out of bounds")
return i
}
return roundDownToNearestCharacter(
scalarAlign(validateInclusiveSubscalarIndex(i)))
}
internal func validateInclusiveCharacterIndex(
_ i: String.Index,
in bounds: Range<String.Index>
) -> String.Index {
_internalInvariant(bounds.upperBound <= endIndex)
if isFastCharacterIndex(i) {
_precondition(i >= bounds.lowerBound && i <= bounds.upperBound,
"Substring index is out of bounds")
return i
}
return roundDownToNearestCharacter(
scalarAlign(validateInclusiveSubscalarIndex(i, in: bounds)),
in: bounds)
}
}
// Temporary additions to deal with binary compatibility issues with existing
// binaries that accidentally pass invalid indices to String APIs in cases that
// were previously undiagnosed.
//
// FIXME: Remove these after a release or two.
extension _StringGuts {
/// A version of `validateInclusiveSubscalarIndex` that only traps if the main
/// executable was linked with Swift Stdlib version 5.7 or better. This is
/// used to work around binary compatibility problems with existing apps that
/// pass invalid indices to String APIs.
internal func validateInclusiveSubscalarIndex_5_7(
_ i: String.Index
) -> String.Index {
let i = ensureMatchingEncoding(i)
_precondition(
ifLinkedOnOrAfter: .v5_7_0,
i._encodedOffset <= count,
"String index is out of bounds")
return i
}
/// A version of `validateInclusiveScalarIndex` that only traps if the main
/// executable was linked with Swift Stdlib version 5.7 or better. This is
/// used to work around binary compatibility problems with existing apps that
/// pass invalid indices to String APIs.
internal func validateInclusiveScalarIndex_5_7(
_ i: String.Index
) -> String.Index {
if isFastScalarIndex(i) {
_precondition(
ifLinkedOnOrAfter: .v5_7_0,
i._encodedOffset <= count,
"String index is out of bounds")
return i
}
return scalarAlign(validateInclusiveSubscalarIndex_5_7(i))
}
/// A version of `validateSubscalarRange` that only traps if the main
/// executable was linked with Swift Stdlib version 5.7 or better. This is
/// used to work around binary compatibility problems with existing apps that
/// pass invalid indices to String APIs.
internal func validateSubscalarRange_5_7(
_ range: Range<String.Index>
) -> Range<String.Index> {
let upper = ensureMatchingEncoding(range.upperBound)
let lower = ensureMatchingEncoding(range.lowerBound)
_precondition(upper <= endIndex && lower <= upper,
"String index range is out of bounds")
return Range(_uncheckedBounds: (lower, upper))
}
/// A version of `validateScalarRange` that only traps if the main executable
/// was linked with Swift Stdlib version 5.7 or better. This is used to work
/// around binary compatibility problems with existing apps that pass invalid
/// indices to String APIs.
internal func validateScalarRange_5_7(
_ range: Range<String.Index>
) -> Range<String.Index> {
if
isFastScalarIndex(range.lowerBound), isFastScalarIndex(range.upperBound)
{
_precondition(
ifLinkedOnOrAfter: .v5_7_0,
range.upperBound._encodedOffset <= count,
"String index range is out of bounds")
return range
}
let r = validateSubscalarRange_5_7(range)
return Range(
_uncheckedBounds: (scalarAlign(r.lowerBound), scalarAlign(r.upperBound)))
}
/// A version of `validateInclusiveCharacterIndex` that only traps if the main
/// executable was linked with Swift Stdlib version 5.7 or better. This is
/// used to work around binary compatibility problems with existing apps that
/// pass invalid indices to String APIs.
internal func validateInclusiveCharacterIndex_5_7(
_ i: String.Index
) -> String.Index {
if isFastCharacterIndex(i) {
_precondition(
ifLinkedOnOrAfter: .v5_7_0,
i._encodedOffset <= count,
"String index is out of bounds")
return i
}
return roundDownToNearestCharacter(
scalarAlign(validateInclusiveSubscalarIndex_5_7(i)))
}
}
// Word index validation (String)
extension _StringGuts {
internal func validateWordIndex(
_ i: String.Index
) -> String.Index {
return roundDownToNearestWord(scalarAlign(validateSubscalarIndex(i)))
}
internal func validateInclusiveWordIndex(
_ i: String.Index
) -> String.Index {
return roundDownToNearestWord(
scalarAlign(validateInclusiveSubscalarIndex(i))
)
}
}