//  [c]
static int process_line(URLContext *h, char *line, int line_count,
                        int *new_location)
{
    HTTPContext *s = h->priv_data;
    const char *auto_method =  h->flags & AVIO_FLAG_READ ? "POST" : "GET";
    char *tag, *p, *end, *method, *resource, *version;
    int ret;

    /* end of header */
    if (line[0] == '\0') {
        s->end_header = 1;
        return 0;
    }

    p = line;
    if (line_count == 0) {
        if (s->is_connected_server) {
            // HTTP method
            method = p;
            while (*p && !av_isspace(*p))
                p++;
            *(p++) = '\0';
            av_log(h, AV_LOG_TRACE, "Received method: %s\n", method);
            if (s->method) {
                if (av_strcasecmp(s->method, method)) {
                    av_log(h, AV_LOG_ERROR, "Received and expected HTTP method do not match. (%s expected, %s received)\n",
                           s->method, method);
                    return ff_http_averror(400, AVERROR(EIO));
                }
            } else {
                // use autodetected HTTP method to expect
                av_log(h, AV_LOG_TRACE, "Autodetected %s HTTP method\n", auto_method);
                if (av_strcasecmp(auto_method, method)) {
                    av_log(h, AV_LOG_ERROR, "Received and autodetected HTTP method did not match "
                           "(%s autodetected %s received)\n", auto_method, method);
                    return ff_http_averror(400, AVERROR(EIO));
                }
                if (!(s->method = av_strdup(method)))
                    return AVERROR(ENOMEM);
            }

            // HTTP resource
            while (av_isspace(*p))
                p++;
            resource = p;
            while (!av_isspace(*p))
                p++;
            *(p++) = '\0';
            av_log(h, AV_LOG_TRACE, "Requested resource: %s\n", resource);
            if (!(s->resource = av_strdup(resource)))
                return AVERROR(ENOMEM);

            // HTTP version
            while (av_isspace(*p))
                p++;
            version = p;
            while (*p && !av_isspace(*p))
                p++;
            *p = '\0';
            if (av_strncasecmp(version, "HTTP/", 5)) {
                av_log(h, AV_LOG_ERROR, "Malformed HTTP version string.\n");
                return ff_http_averror(400, AVERROR(EIO));
            }
            av_log(h, AV_LOG_TRACE, "HTTP version string: %s\n", version);
        } else {
            while (!av_isspace(*p) && *p != '\0')
                p++;
            while (av_isspace(*p))
                p++;
            s->http_code = strtol(p, &end, 10);

            av_log(h, AV_LOG_TRACE, "http_code=%d\n", s->http_code);

            if ((ret = check_http_code(h, s->http_code, end)) < 0)
                return ret;
        }
    } else {
        while (*p != '\0' && *p != ':')
            p++;
        if (*p != ':')
            return 1;

        *p  = '\0';
        tag = line;
        p++;
        while (av_isspace(*p))
            p++;
        if (!av_strcasecmp(tag, "Location")) {
            if ((ret = parse_location(s, p)) < 0)
                return ret;
            *new_location = 1;
        } else if (!av_strcasecmp(tag, "Content-Length") && s->filesize == -1) {
            s->filesize = strtoll(p, NULL, 10);
        } else if (!av_strcasecmp(tag, "Content-Range")) {
            parse_content_range(h, p);
        } else if (!av_strcasecmp(tag, "Accept-Ranges") &&
                   !strncmp(p, "bytes", 5) &&
                   s->seekable == -1) {
            h->is_streamed = 0;
        } else if (!av_strcasecmp(tag, "Transfer-Encoding") &&
                   !av_strncasecmp(p, "chunked", 7)) {
            s->filesize  = -1;
            s->chunksize = 0;
        } else if (!av_strcasecmp(tag, "WWW-Authenticate")) {
            ff_http_auth_handle_header(&s->auth_state, tag, p);
        } else if (!av_strcasecmp(tag, "Authentication-Info")) {
            ff_http_auth_handle_header(&s->auth_state, tag, p);
        } else if (!av_strcasecmp(tag, "Proxy-Authenticate")) {
            ff_http_auth_handle_header(&s->proxy_auth_state, tag, p);
        } else if (!av_strcasecmp(tag, "Connection")) {
            if (!strcmp(p, "close"))
                s->willclose = 1;
        } else if (!av_strcasecmp(tag, "Server")) {
            if (!av_strcasecmp(p, "AkamaiGHost")) {
                s->is_akamai = 1;
            } else if (!av_strncasecmp(p, "MediaGateway", 12)) {
                s->is_mediagateway = 1;
            }
        } else if (!av_strcasecmp(tag, "Content-Type")) {
            av_free(s->mime_type);
            s->mime_type = av_strdup(p);
        } else if (!av_strcasecmp(tag, "Set-Cookie")) {
            if (parse_cookie(s, p, &s->cookie_dict))
                av_log(h, AV_LOG_WARNING, "Unable to parse '%s'\n", p);
        } else if (!av_strcasecmp(tag, "Icy-MetaInt")) {
            s->icy_metaint = strtoll(p, NULL, 10);
        } else if (!av_strncasecmp(tag, "Icy-", 4)) {
            if ((ret = parse_icy(s, tag, p)) < 0)
                return ret;
        } else if (!av_strcasecmp(tag, "Content-Encoding")) {
            if ((ret = parse_content_encoding(h, p)) < 0)
                return ret;
        }
    }
    return 1;
}