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.
39 lines
1.8 KiB
Swift
39 lines
1.8 KiB
Swift
public extension PureXML.Parsing {
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/// A character encoding PureXML can decode from raw bytes. XML processors are
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/// required to support UTF-8 and UTF-16; those are covered here. Other declared
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/// encodings are out of scope (and reported as malformed rather than guessed).
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enum InputEncoding: String, Equatable, Sendable {
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case utf8
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case utf16BigEndian
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case utf16LittleEndian
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/// Detects the encoding from the leading bytes, following the XML sniff
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/// order: a byte-order mark first, then the `<?` byte pattern of the XML
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/// declaration, defaulting to UTF-8 when neither is present.
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public static func detect(_ bytes: [UInt8]) -> InputEncoding {
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detectWithBOM(bytes).encoding
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}
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/// Detects the encoding and the length of any byte-order mark to strip.
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static func detectWithBOM(_ bytes: [UInt8]) -> (encoding: InputEncoding, bomLength: Int) {
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if bytes.count >= 3, bytes[0] == 0xEF, bytes[1] == 0xBB, bytes[2] == 0xBF {
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return (.utf8, 3)
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}
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if bytes.count >= 2, bytes[0] == 0xFE, bytes[1] == 0xFF {
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return (.utf16BigEndian, 2)
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}
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if bytes.count >= 2, bytes[0] == 0xFF, bytes[1] == 0xFE {
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return (.utf16LittleEndian, 2)
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}
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// No BOM: sniff the "<?" pattern of an XML declaration.
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if bytes.count >= 4, bytes[0] == 0x00, bytes[1] == 0x3C, bytes[2] == 0x00, bytes[3] == 0x3F {
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return (.utf16BigEndian, 0)
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}
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if bytes.count >= 4, bytes[0] == 0x3C, bytes[1] == 0x00, bytes[2] == 0x3F, bytes[3] == 0x00 {
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return (.utf16LittleEndian, 0)
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}
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return (.utf8, 0)
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}
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}
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}
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