//liveMedia/RTSPServer.cpp #478附近
    lookForHeader("x-sessioncookie", &reqStr[i], reqStrSize-i, sessionCookie, sessionCookieMaxSize);
    lookForHeader("Accept", &reqStr[i], reqStrSize-i, acceptStr, acceptStrMaxSize);

//liveMedia/RTSPServer.cpp #825附近
    ...
    // The request was not (valid) RTSP, but check for a special case:
    // HTTP commands (for setting up RTSP-over-HTTP tunneling):
->  char sessionCookie[RTSP_PARAM_STRING_MAX];  
    //RTSP_PARAM_STRING_MAX 200
->  char acceptStr[RTSP_PARAM_STRING_MAX];      
    //RTSP_PARAM_STRING_MAX 200
    *fLastCRLF = '\0'; // temporarily, for parsing
    parseSucceeded = parseHTTPRequestString(cmdName, sizeof cmdName,
        urlSuffix, sizeof urlPreSuffix,
        sessionCookie, sizeof sessionCookie,
        acceptStr, sizeof acceptStr);
    *fLastCRLF = '\r';

static void lookForHeader(char const* headerName, 
                            char const* source, 
                            unsigned sourceLen, 
                            char* resultStr, 
                            unsigned resultMaxSize) {
    resultStr[0] = '\0';  // by default, return an empty string
    unsigned headerNameLen = strlen(headerName);
①---for (int i = 0; i < (int)(sourceLen-headerNameLen); ++i) {
②------if (strncmp(&source[i], headerName, headerNameLen) == 0 && source[i+headerNameLen] == ':') {
        // We found the header.  Skip over any whitespace, then copy the rest of the line to "resultStr":
        for (i += headerNameLen+1; i < (int)sourceLen && (source[i] == ' ' || source[i] == '\t'); ++i) {}
③----------for (unsigned j = i; j < sourceLen; ++j) {
                if (source[j] == '\r' || source[j] == '\n') {
                    // We've found the end of the line.  Copy it to the result (if it will fit):
                    if (j-i+1 > resultMaxSize) break;
                    char const* resultSource = &source[i];
                    char const* resultSourceEnd = &source[j];
                    while (resultSource < resultSourceEnd) *resultStr++ = *resultSource++;
                    *resultStr = '\0';
④ -----------------break;
                }
            }
        }
    }
}