parseHeaderAndEnvelope()

bool fl::fled::parseHeaderAndEnvelope	(	const fl::u8 *	data,
		fl::size	len,
		ParsedHeader *	outHeader,
		fl::json *	outEnvelope )

Definition at line 22 of file parser.cpp.hpp.

                                                              {
    if (!outHeader || !outEnvelope) {
        return false;
    }
    if (!data) {
        return false;
    }
    if (len < kHeaderBytes) {
        return false;
    }
    if (data[0] != kMagic[0] || data[1] != kMagic[1] ||
        data[2] != kMagic[2] || data[3] != kMagic[3]) {
        return false;
    }
    const fl::u8 ver = data[4];
    if (ver != kVersionV1) {
        return false;
    }
    if (data[6] != 0 || data[7] != 0) {
        return false;
    }
    const fl::u8 pixelFormat = data[5];
    const fl::u32 jsonLen =
        static_cast<fl::u32>(data[8]) |
        (static_cast<fl::u32>(data[9]) << 8) |
        (static_cast<fl::u32>(data[10]) << 16) |
        (static_cast<fl::u32>(data[11]) << 24);
    // Bound-check in u32 BEFORE narrowing to fl::size - on 16-bit targets
    // (AVR) fl::size is 16 bits and naive narrowing would wraparound.
    if (jsonLen > static_cast<fl::u32>(kMaxJsonBytes)) {
        return false;
    }
    if (jsonLen > static_cast<fl::u32>(len - kHeaderBytes)) {
        return false;
    }
    const fl::size jsonLenSz = static_cast<fl::size>(jsonLen);
    // Build a string view over the JSON bytes (fl::string copies the bytes
    // internally - required because json::parse takes const string&).
    fl::string jsonText(fl::reinterpret_cast_<const char *>(data + kHeaderBytes),
                        jsonLenSz);
    fl::json parsed = fl::json::parse(jsonText);
    // parse() returns json(nullptr) on failure - that flags an envelope
    // that is not a valid JSON document. Strict-reject per design.
    if (!parsed.has_value()) {
        return false;
    }
    outHeader->version = ver;
    outHeader->pixelFormat = pixelFormat;
    outHeader->payloadOffset = kHeaderBytes + jsonLenSz;
    *outEnvelope = parsed;
    return true;
}

References fl::FL_NO_EXCEPT, fl::json::has_value(), fl::json::parse(), and fl::reinterpret_cast_().

Referenced by fl::Fled::loadFromStatic(), and fl::Fled::loadFromVector().

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