Mihaela Mihaljevic
e4b2e0127d
Add PureXML.parse(bytes:) and events(bytes:) for raw [UInt8] input. The encoding is detected following the XML sniff order (BOM first, then the <? byte pattern, defaulting to UTF-8) and decoded with the Swift standard library only, so the package stays Foundation-free and portable. UTF-8 and UTF-16 (both byte orders, with or without a BOM) are supported, the encoding set the XML spec requires. Malformed input (odd-length UTF-16) raises ParseError.malformedEncoding. PureXML.Parsing.InputEncoding.detect(_:) exposes the detector. The lint rule optional_data_string_conversion is disabled because its suggested fix is a Foundation API this package cannot use. Reimplemented from the documented XML byte-detection algorithm; no upstream code copied.
36 lines
1.6 KiB
Swift
36 lines
1.6 KiB
Swift
extension PureXML.Parsing {
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/// Decodes raw bytes into a string using the detected encoding, stripping any
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/// byte-order mark. UTF-8 and UTF-16 (both byte orders) are supported, which
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/// is the encoding set the XML specification requires of every processor.
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/// Uses only the Swift standard library (no Foundation), so it stays portable.
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enum ByteDecoder {
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static func decode(_ bytes: [UInt8]) throws -> String {
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let (encoding, bomLength) = InputEncoding.detectWithBOM(bytes)
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let body = bytes.dropFirst(bomLength)
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switch encoding {
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case .utf8:
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return String(decoding: body, as: UTF8.self)
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case .utf16BigEndian:
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return try decodeUTF16(body, bigEndian: true)
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case .utf16LittleEndian:
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return try decodeUTF16(body, bigEndian: false)
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}
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}
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private static func decodeUTF16(_ bytes: ArraySlice<UInt8>, bigEndian: Bool) throws -> String {
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guard bytes.count.isMultiple(of: 2) else {
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throw PureXML.Parsing.ParseError.malformedEncoding
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}
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var units: [UInt16] = []
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units.reserveCapacity(bytes.count / 2)
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var iterator = bytes.makeIterator()
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while let first = iterator.next(), let second = iterator.next() {
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let high = UInt16(first)
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let low = UInt16(second)
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units.append(bigEndian ? (high << 8 | low) : (low << 8 | high))
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}
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return String(decoding: units, as: UTF16.self)
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}
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}
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}
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