初步添加sdp相关代码

webrtc/Sdp.cpp

+//
+// Created by xzl on 2021/3/27.
+//
+
+#include "Sdp.h"

webrtc/Sdp.h

+//
+// Created by xzl on 2021/3/27.
+//
+
+#ifndef ZLMEDIAKIT_SDP_H
+#define ZLMEDIAKIT_SDP_H
+
+#include <list>
+#include <string>
+using namespace std;
+
+enum class RtpDirection {
+    invalid = -1,
+    //只发送
+    sendonly,
+    //只接收
+    revonly,
+    //同时发送接收
+    sendrecv,
+    //禁止发送数据
+    inactive
+};
+
+enum class DtlsRole {
+    invalid = -1,
+    //客户端
+    active,
+    //服务端
+    passive,
+    //既可作做客户端也可以做服务端
+    actpass,
+};
+
+enum class SdpType {
+    invalid = -1,
+    offer,
+    answer
+};
+
+//
+//v=0
+//o=- 7268199939077294076 2 IN IP4 127.0.0.1
+//s=-
+//t=0 0
+//a=group:BUNDLE video
+//a=msid-semantic: WMS
+//m=video 9 RTP/SAVPF 96
+//c=IN IP4 0.0.0.0
+//a=rtcp:9 IN IP4 0.0.0.0
+//a=ice-ufrag:y94W
+//a=ice-pwd:fuz1hZCAarezk35fruVGfdyP
+//a=ice-options:trickle
+//a=fingerprint:sha-256 FF:8C:29:B8:B3:2B:45:F5:21:D2:47:D5:EE:B7:F8:BB:F1:DC:95:47:7B:20:B4:59:75:0F:16:93:D0:AC:D2:73
+//a=setup:active
+//a=mid:video
+//a=recvonly
+//a=rtcp-mux
+//a=rtpmap:96 H264/90000
+//a=fmtp:96 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f
+
+//Session description
+//         v=  (protocol version)
+//         o=  (originator and session identifier)
+//         s=  (session name)
+//         i=* (session information)
+//         u=* (URI of description)
+//         e=* (email address)
+//         p=* (phone number)
+//         c=* (connection information -- not required if included in
+//              all media)
+//         b=* (zero or more bandwidth information lines)
+//         One or more time descriptions ("t=" and "r=" lines; see below)
+//         z=* (time zone adjustments)
+//         k=* (encryption key)
+//         a=* (zero or more session attribute lines)
+//         Zero or more media descriptions
+//
+//      Time description
+//         t=  (time the session is active)
+//         r=* (zero or more repeat times)
+//
+//      Media description, if present
+//         m=  (media name and transport address)
+//         i=* (media title)
+//         c=* (connection information -- optional if included at
+//              session level)
+//         b=* (zero or more bandwidth information lines)
+//         k=* (encryption key)
+//         a=* (zero or more media attribute lines)
+
+class SdpItem {
+public:
+    SdpItem() = default;
+    virtual ~SdpItem() = default;
+    virtual void parse(const string &str) = 0;
+    virtual string toString() const = 0;
+};
+
+class SdpTime : public SdpItem{
+public:
+    float start;
+    float end;
+    void parse(const string &str) override;
+    string toString() const override;
+};
+
+class SdpAttr : public SdpItem{
+public:
+    string name;
+    string value;
+    void parse(const string &str) override;
+    string toString() const override;
+};
+
+class SdpOrigin : public SdpItem{
+public:
+    // https://datatracker.ietf.org/doc/rfc4566/?include_text=1 5.2.  Origin ("o=")
+    // o=jdoe 2890844526 2890842807 IN IP4 10.47.16.5
+    // o=<username> <sess-id> <sess-version> <nettype> <addrtype> <unicast-address>
+    string username;
+    string session_id;
+    string session_version;
+    string nettype;
+    string addrtype;
+    string address;
+    void parse(const string &str) override;
+    string toString() const override;
+};
+
+class SdpConnection : public SdpItem {
+public:
+    //  https://datatracker.ietf.org/doc/rfc4566/?include_text=1 5.7.  Connection Data ("c=")
+    // c=IN IP4 224.2.17.12/127
+    // c=<nettype> <addrtype> <connection-address>
+    string nettype;
+    string addrtype;
+    string address;
+    void parse(const string &str) override;
+    string toString() const override;
+};
+
+class RtcMedia {
+public:
+
+};
+class RtcSdp {
+public:
+    /////Session description（会话级别描述）////
+    //v=  (protocol version)
+    int version;
+    //o=  (session origin information )
+    SdpOrigin origin;
+    //s=  (session name)
+    string session_name;
+    //i=* (session information)
+    string session_information;
+    //c=* (connection information -- not required if included in all media)
+    SdpConnection connection;
+
+    //// Time description ////
+    //t=  (time the session is active)
+    SdpTime time;
+    //r=* (zero or more repeat times)
+    int repeat;
+    //a=* (zero or more media attribute lines)
+    list<SdpAttr> attributes;
+
+};
+
+
+
+
+#endif //ZLMEDIAKIT_SDP_H