Asynchronous & Stream Parsing

SIP traffic over TCP or TLS arrives in continuous stream buffers where multiple SIP frames can be packed together, or where a single frame might be partially received.

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Stream Processing Mechanics

sip2json::parseAsync operates directly over string iterators (std::string::const_iterator or std::string::iterator), advancing the start iterator as frames are successfully recognized.

#include "siddiqsoft/sip2json.hpp"

using namespace siddiqsoft;

void onNetworkBufferReceived(std::string& tcpBuffer)
{
    auto cursor = tcpBuffer.begin();

    // Iterate through buffer and invoke callback for each complete SIP frame
    sip2json::parseAsync(
        cursor,
        tcpBuffer.end(),
        [](sipmessage&& msg) {
            // Processing valid message
            std::cout << "Method: " << msg.method << ", CSeq: " << msg.cseq << "\n";
        },
        [](sip2jsonErrors& err, const std::string& description) {
            std::cerr << "Parse error (" << static_cast<int>(err) << "): " << description << "\n";
        }
    );

    // Erase processed frames from front of buffer; incomplete frames remain for next packet
    tcpBuffer.erase(tcpBuffer.begin(), cursor);
}

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Performance & Ownership Highlights

1. Move Semantics: Messages passed to the success callback are moved (sipmessage&&), giving zero-copy ownership to the handler.
2. Buffer Residuals: If a partial frame remains at the end of the buffer, parseAsync stops without erasing it, allowing next read cycles to append data seamlessly.
3. No Allocation Spikes: Internal parsing uses Compile-Time Regular Expressions (CTRE) for fast header identification.