[!] fix bugs and building error on ubuntu and macOS, add initial rtt

CMakeLists.txt

@@ -359,6 +359,7 @@ if(PLATFORM MATCHES "mac")
         ${SSL_LIB_PATH}
         "-Wl"
         -lpthread
+        -lstdc++
     )
 else()
     target_link_libraries(

demo/demo_client.c

@@ -190,6 +190,8 @@ typedef struct xqc_demo_cli_quic_config_s {
 
     size_t max_pkt_sz;
 
+    char co_str[XQC_CO_STR_MAX_LEN];
+
 } xqc_demo_cli_quic_config_t;
 
 
@@ -1265,9 +1267,9 @@ xqc_demo_cli_h3_request_close_notify(xqc_h3_request_t *h3_request, void *user_da
     xqc_request_stats_t stats;
     stats = xqc_h3_request_get_stats(h3_request);
     printf("send_body_size:%zu, recv_body_size:%zu, send_header_size:%zu, recv_header_size:%zu, "
-           "recv_fin:%d, err:%d, rate_limit:%"PRIu64", mp_state:%d, avail_send_weight:%.3lf, avail_recv_weight:%.3lf\n", 
+           "recv_fin:%d, err:%d, rate_limit:%"PRIu64", mp_state:%d, early_data:%d, avail_send_weight:%.3lf, avail_recv_weight:%.3lf\n", 
            stats.send_body_size, stats.recv_body_size, stats.send_header_size, stats.recv_header_size, 
-           user_stream->recv_fin, stats.stream_err, stats.rate_limit, stats.mp_state,
+           user_stream->recv_fin, stats.stream_err, stats.rate_limit, stats.mp_state, stats.early_data_state,
            stats.mp_default_path_send_weight, stats.mp_default_path_recv_weight);
 
     printf("\033[33m[H3-req] send_bytes:%zu, recv_bytes:%zu, path_info:%s\n\033[0m", 
@@ -1337,19 +1339,11 @@ xqc_demo_cli_socket_read_handler(xqc_demo_cli_user_conn_t *user_conn, int fd)
         recv_sum += recv_size;
         uint64_t recv_time = xqc_now();
         user_path->last_sock_op_time = recv_time;
-#ifdef XQC_NO_PID_PACKET_PROCESS
         if (xqc_engine_packet_process(user_conn->ctx->engine, packet_buf, recv_size,
                                       (struct sockaddr *)(&user_path->local_addr),
                                       user_path->local_addrlen, (struct sockaddr *)(&addr),
                                       addr_len, (xqc_msec_t)recv_time,
                                       user_conn) != XQC_OK)
-#else
-        if (xqc_engine_packet_process(user_conn->ctx->engine, packet_buf, recv_size,
-                                      (struct sockaddr *)(&user_path->local_addr),
-                                      user_path->local_addrlen, (struct sockaddr *)(&addr),
-                                      addr_len, user_path->path_id, (xqc_msec_t)recv_time,
-                                      user_conn) != XQC_OK)
-#endif
         {
             return;
         }
@@ -1630,7 +1624,7 @@ xqc_demo_cli_init_conneciton_settings(xqc_conn_settings_t* settings,
     settings->pacing_on = args->net_cfg.pacing;
     settings->cong_ctrl_callback = cong_ctrl;
     settings->cc_params.customize_on = 1,
-    settings->cc_params.init_cwnd = 32,
+    settings->cc_params.init_cwnd = 96,
     settings->so_sndbuf = 1024*1024;
     settings->proto_version = XQC_VERSION_V1;
     settings->spurious_loss_detect_on = 1;
@@ -1651,6 +1645,7 @@ xqc_demo_cli_init_conneciton_settings(xqc_conn_settings_t* settings,
         settings->enable_stream_rate_limit = 1;
         settings->recv_rate_bytes_per_sec = 0;
     }
+    strncpy(settings->conn_option_str, args->quic_cfg.co_str, XQC_CO_STR_MAX_LEN);
 }
 
 /* set client args to default values */
@@ -1797,14 +1792,15 @@ xqc_demo_cli_usage(int argc, char *argv[])
         "   -e    NAT rebinding on path 0\n"
         "   -E    NAT rebinding on path 1\n"
         "   -F    MTU size (default: 1200)\n"
+        "   -G    Google connection options (e.g. CBBR,TBBR)\n"
         , prog);
 }
 
 void
 xqc_demo_cli_parse_args(int argc, char *argv[], xqc_demo_cli_client_args_t *args)
 {
     int ch = 0;
-    while ((ch = getopt(argc, argv, "a:p:c:Ct:S:0m:A:D:l:L:k:K:U:u:dMoi:w:Ps:bZ:NQT:R:V:B:I:n:eEF:")) != -1) {
+    while ((ch = getopt(argc, argv, "a:p:c:Ct:S:0m:A:D:l:L:k:K:U:u:dMoi:w:Ps:bZ:NQT:R:V:B:I:n:eEF:G:")) != -1) {
         switch (ch) {
         /* server ip */
         case 'a':
@@ -2043,6 +2039,11 @@ xqc_demo_cli_parse_args(int argc, char *argv[], xqc_demo_cli_client_args_t *args
             printf("MTU size: %s\n", optarg);
             args->quic_cfg.max_pkt_sz = atoi(optarg);
             break;
+
+        case 'G':
+            printf("Google connection options: %s\n", optarg);
+            strncpy(args->quic_cfg.co_str, optarg, XQC_CO_STR_MAX_LEN);
+            break;
 
         default:
             printf("other option :%c\n", ch);
@@ -2266,7 +2267,7 @@ xqc_demo_cli_h3_conn_close_notify(xqc_h3_conn_t *h3_conn, const xqc_cid_t *cid,
     xqc_demo_cli_user_conn_t *user_conn = (xqc_demo_cli_user_conn_t *)user_data;
     xqc_conn_stats_t stats = xqc_conn_get_stats(user_conn->ctx->engine, cid);
     printf("send_count:%u, lost_count:%u, tlp_count:%u, recv_count:%u, srtt:%"PRIu64" "
-           "early_data_flag:%d, conn_err:%d, ack_info:%s conn_info:%s\n", stats.send_count, stats.lost_count,
+           "early_data_flag:%d, conn_err:%d, ack_info:%s, conn_info:%s\n", stats.send_count, stats.lost_count,
            stats.tlp_count, stats.recv_count, stats.srtt, stats.early_data_flag, stats.conn_err,
            stats.ack_info, stats.conn_info);
 

demo/demo_server.c

@@ -1052,17 +1052,10 @@ xqc_demo_svr_socket_read_handler(xqc_demo_svr_ctx_t *ctx, int fd)
         recv_sum += recv_size;
 
         uint64_t recv_time = xqc_now();
-#ifdef  XQC_NO_PID_PACKET_PROCESS
         xqc_int_t ret = xqc_engine_packet_process(ctx->engine, packet_buf, recv_size,
                                       (struct sockaddr *)(&ctx->local_addr), ctx->local_addrlen,
                                       (struct sockaddr *)(&peer_addr), peer_addrlen,
                                       (xqc_usec_t)recv_time, ctx);
-#else
-        xqc_int_t ret = xqc_engine_packet_process(ctx->engine, packet_buf, recv_size,
-                                      (struct sockaddr *)(&ctx->local_addr), ctx->local_addrlen,
-                                      (struct sockaddr *)(&peer_addr), peer_addrlen, XQC_UNKNOWN_PATH_ID,
-                                      (xqc_usec_t)recv_time, ctx);
-#endif
         if (ret != XQC_OK) {
             printf("server_read_handler: packet process err, ret: %d\n", ret);
             return;

include/xquic/xqc_http3.h

@@ -156,6 +156,14 @@ typedef struct xqc_request_stats_s {
 
     uint64_t    rate_limit;
 
+    /**
+     * @brief 0RTT state
+     * 0: no 0RTT
+     * 1: 0RTT accept
+     * 2: 0RTT reject
+     */
+    uint8_t     early_data_state;
+
     char        stream_info[XQC_STREAM_INFO_LEN];
 } xqc_request_stats_t;
 

include/xquic/xquic.h

@@ -71,6 +71,9 @@ typedef enum xqc_proto_version_s {
 
 #define XQC_DGRAM_RETX_ASKED_BY_APP     1
 
+#define XQC_CO_MAX_NUM                  16
+#define XQC_CO_STR_MAX_LEN              (5 * XQC_CO_MAX_NUM)
+
 
 /**
  * @brief get timestamp callback function. this might be useful on different platforms
@@ -1263,6 +1266,19 @@ typedef struct xqc_conn_settings_s {
     uint8_t                     protect_pool_mem;
 #endif
 
+    char                        conn_option_str[XQC_CO_STR_MAX_LEN];
+
+    /**
+     * @brief intial_rtt (us). Default: 0 (use the internal default value -- 250000)
+     * 
+     */
+    xqc_usec_t                  initial_rtt;
+    /**
+     * @brief initial pto duration (us). Default: 0 (use the internal default value -- 3xinitial_rtt)
+     * 
+     */
+    xqc_usec_t                  initial_pto_duration;
+
 } xqc_conn_settings_t;
 
 
@@ -1335,6 +1351,11 @@ typedef struct xqc_conn_stats_s {
     char                alpn[XQC_MAX_ALPN_BUF_LEN];
 } xqc_conn_stats_t;
 
+typedef struct xqc_conn_qos_stats_s {
+    xqc_usec_t          srtt;            /* smoothed SRTT at present: initial value = 250000 */
+    xqc_usec_t          min_rtt;         /* minimum RTT until now: initial value = 0xFFFFFFFF */
+    uint64_t            inflight_bytes;  /* initial value = 0 */
+} xqc_conn_qos_stats_t;
 
 /*************************************************************
  *  engine layer APIs
@@ -1400,29 +1421,14 @@ xqc_int_t xqc_engine_unregister_alpn(xqc_engine_t *engine, const char *alpn, siz
  * Pass received UDP packet payload into xquic engine.
  * @param recv_time   UDP packet received time in microsecond
  * @param user_data   connection user_data, server is NULL
- * @param path_id     XQC_UNKNOWN_PATH_ID = unknown path (only use cid to identify the path)
  */
-
-#ifdef XQC_NO_PID_PACKET_PROCESS
-
 XQC_EXPORT_PUBLIC_API
 xqc_int_t xqc_engine_packet_process(xqc_engine_t *engine,
     const unsigned char *packet_in_buf, size_t packet_in_size,
     const struct sockaddr *local_addr, socklen_t local_addrlen,
     const struct sockaddr *peer_addr, socklen_t peer_addrlen,
     xqc_usec_t recv_time, void *user_data);
 
-#else
-
-XQC_EXPORT_PUBLIC_API
-xqc_int_t xqc_engine_packet_process(xqc_engine_t *engine,
-    const unsigned char *packet_in_buf, size_t packet_in_size,
-    const struct sockaddr *local_addr, socklen_t local_addrlen,
-    const struct sockaddr *peer_addr, socklen_t peer_addrlen,
-    uint64_t path_id, xqc_usec_t recv_time, void *user_data);
-
-#endif
-
 
 /**
  * @brief Process all connections, application implements MUST call this function in timer callback
@@ -1817,6 +1823,13 @@ void xqc_conn_continue_send_by_conn(xqc_connection_t *conn);
 XQC_EXPORT_PUBLIC_API
 xqc_conn_stats_t xqc_conn_get_stats(xqc_engine_t *engine, const xqc_cid_t *cid);
 
+
+/**
+ * User can get xqc_conn_qos_stats_t by cid
+ */
+XQC_EXPORT_PUBLIC_API
+xqc_conn_qos_stats_t xqc_conn_get_qos_stats(xqc_engine_t *engine, const xqc_cid_t *cid);
+
 /**
  * create new path for client
  * @param cid scid for connection

include/xquic/xquic_typedef.h

@@ -94,6 +94,7 @@ typedef struct xqc_path_ctx_s               xqc_path_ctx_t;
 typedef struct xqc_timer_manager_s          xqc_timer_manager_t;
 typedef struct xqc_h3_ext_bytestream_s      xqc_h3_ext_bytestream_t;
 typedef struct xqc_ping_record_s            xqc_ping_record_t;
+typedef struct xqc_conn_qos_stats_s         xqc_conn_qos_stats_t;
 
 typedef uint64_t        xqc_msec_t; /* store millisecond values */
 typedef uint64_t        xqc_usec_t; /* store microsecond values */
@@ -221,4 +222,61 @@ typedef struct xqc_stream_settings_s {
     uint64_t recv_rate_bytes_per_sec;
 } xqc_stream_settings_t;
 
+#define XQC_CO_TAG(a, b, c, d) (uint32_t)((a << 24) + (b << 16) + (c << 8) + d)
+
+typedef enum xqc_conn_option_e {
+    XQC_CO_TBBR = XQC_CO_TAG('T', 'B', 'B', 'R'),    // Reduced Buffer Bloat TCP
+    XQC_CO_1RTT = XQC_CO_TAG('1', 'R', 'T', 'T'),    // STARTUP in BBR for 1 RTT
+    XQC_CO_2RTT = XQC_CO_TAG('2', 'R', 'T', 'T'),    // STARTUP in BBR for 2 RTTs
+    XQC_CO_BBR4 = XQC_CO_TAG('B', 'B', 'R', '4'),    // 20 RTT ack aggregation
+    XQC_CO_BBR5 = XQC_CO_TAG('B', 'B', 'R', '5'),    // 40 RTT ack aggregation
+    XQC_CO_IW03 = XQC_CO_TAG('I', 'W', '0', '3'),    // Force ICWND to 3
+    XQC_CO_IW10 = XQC_CO_TAG('I', 'W', '1', '0'),    // Force ICWND to 10
+    XQC_CO_IW20 = XQC_CO_TAG('I', 'W', '2', '0'),    // Force ICWND to 20
+    XQC_CO_IW50 = XQC_CO_TAG('I', 'W', '5', '0'),    // Force ICWND to 50
+    XQC_CO_B2ON = XQC_CO_TAG('B', '2', 'O', 'N'),    // Enable BBRv2
+    XQC_CO_COPA = XQC_CO_TAG('C', 'O', 'P', 'A'),    // Enable COPA
+    XQC_CO_C2ON = XQC_CO_TAG('C', '2', 'O', 'N'),    // Enable CopaV2
+    XQC_CO_QBIC = XQC_CO_TAG('Q', 'B', 'I', 'C'),    // TCP Cubic
+    XQC_CO_RENO = XQC_CO_TAG('R', 'E', 'N', 'O'),    // Enable reno
+    XQC_CO_SPRI = XQC_CO_TAG('S', 'P', 'R', 'I'),    // enable stream priority by streamid
+    XQC_CO_9218 = XQC_CO_TAG('9', '2', '1', '8'),    // enable stream priority by rfc9218
+    XQC_CO_D218 = XQC_CO_TAG('D', '2', '1', '8'),    // disable rfc9218
+    XQC_CO_DRST = XQC_CO_TAG('D', 'R', 'S', 'T'),    // disable cease sending stream
+    XQC_CO_CBBR = XQC_CO_TAG('C', 'B', 'B', 'R'),    // A global option to enable all the following options (Customized BBR)
+    XQC_CO_BNLS = XQC_CO_TAG('B', 'N', 'L', 'S'),    // Force BBR not to respond on losses during STARTUP
+    XQC_CO_BACG = XQC_CO_TAG('B', 'A', 'C', 'G'),    // Use Adaptive CWND_GAIN in BBR
+    XQC_CO_CG03 = XQC_CO_TAG('C', 'G', '0', '3'),    // Use 3 for CWND_GAIN in BBR
+    XQC_CO_CG05 = XQC_CO_TAG('C', 'G', '0', '5'),    // Use 5 for CWND_GAIN in BBR
+    XQC_CO_CG10 = XQC_CO_TAG('C', 'G', '1', '0'),    // Use 10 for CWND_GAIN in BBR
+    XQC_CO_CG20 = XQC_CO_TAG('C', 'G', '2', '0'),    // Use 20 for CWND_GAIN in BBR
+    XQC_CO_PG11 = XQC_CO_TAG('P', 'G', '1', '1'),    // Use 1.1 for PACING_GAIN in BBR PROBE_UP
+    XQC_CO_PG15 = XQC_CO_TAG('P', 'G', '1', '5'),    // Use 1.5 for PACING_GAIN in BBR PROBE_UP
+    XQC_CO_BNLR = XQC_CO_TAG('B', 'N', 'L', 'R'),    // Disable BBR's loss recovery state
+    XQC_CO_MW10 = XQC_CO_TAG('M', 'W', '1', '0'),    // Set min CWND to 10
+    XQC_CO_MW20 = XQC_CO_TAG('M', 'W', '2', '0'),    // Set min CWND to 20
+    XQC_CO_MW32 = XQC_CO_TAG('M', 'W', '3', '2'),    // Set min CWND to 32
+    XQC_CO_MW50 = XQC_CO_TAG('M', 'W', '5', '0'),    // Set min CWND to 50
+    XQC_CO_WL20 = XQC_CO_TAG('W', 'L', '2', '0'),    // Set BW window length to 20 (RTTs)
+    XQC_CO_WL30 = XQC_CO_TAG('W', 'L', '3', '0'),    // Set BW window length to 30 (RTTs)
+    XQC_CO_WL40 = XQC_CO_TAG('W', 'L', '4', '0'),    // Set BW window length to 40 (RTTs)
+    XQC_CO_WL50 = XQC_CO_TAG('W', 'L', '5', '0'),    // Set BW window length to 50 (RTTs)
+    XQC_CO_PR02 = XQC_CO_TAG('P', 'R', '0', '2'),    // Set the target CWND in ProbeRTT to 0.2xBDP
+    XQC_CO_PR03 = XQC_CO_TAG('P', 'R', '0', '3'),    // Set the target CWND in ProbeRTT to 0.3xBDP
+    XQC_CO_PR04 = XQC_CO_TAG('P', 'R', '0', '4'),    // Set the target CWND in ProbeRTT to 0.4xBDP
+    XQC_CO_PR05 = XQC_CO_TAG('P', 'R', '0', '5'),    // Set the target CWND in ProbeRTT to 0.5xBDP
+    XQC_CO_PR06 = XQC_CO_TAG('P', 'R', '0', '6'),    // Set the target CWND in ProbeRTT to 0.6xBDP
+    XQC_CO_PR07 = XQC_CO_TAG('P', 'R', '0', '7'),    // Set the target CWND in ProbeRTT to 0.7xBDP
+    XQC_CO_ENWC = XQC_CO_TAG('E', 'N', 'W', 'C'),    // Enable CWND compensation according to jitter
+    XQC_CO_JW10 = XQC_CO_TAG('J', 'W', '1', '0'),    // Set the window length of max jitter filter to 10xRTT (default)
+    XQC_CO_JW20 = XQC_CO_TAG('J', 'W', '2', '0'),    // Set the window length of max jitter filter to 20xRTT
+    XQC_CO_JW30 = XQC_CO_TAG('J', 'W', '3', '0'),    // Set the window length of max jitter filter to 30xRTT
+    XQC_CO_JW40 = XQC_CO_TAG('J', 'W', '4', '0'),    // Set the window length of max jitter filter to 40xRTT
+    XQC_CO_JW50 = XQC_CO_TAG('J', 'W', '5', '0'),    // Set the window length of max jitter filter to 50xRTT
+    XQC_CO_SL03 = XQC_CO_TAG('S', 'L', '0', '3'),    // Set the STARTUP loss rate threshold to 0.03
+    XQC_CO_SL04 = XQC_CO_TAG('S', 'L', '0', '4'),    // Set the STARTUP loss rate threshold to 0.04
+    XQC_CO_SL05 = XQC_CO_TAG('S', 'L', '0', '5'),    // Set the STARTUP loss rate threshold to 0.05
+    XQC_CO_SL10 = XQC_CO_TAG('S', 'L', '1', '0'),    // Set the STARTUP loss rate threshold to 0.05    
+} xqc_conn_option_t;
+
 #endif /*_XQUIC_TYPEDEF_H_INCLUDED_*/

scripts/case_test.sh

@@ -723,6 +723,22 @@ fi
 grep_err_log
 
 
+clear_log
+echo -e "empty header value ...\c"
+${CLIENT_BIN} -x 47 -1 -n 10 >> stdlog
+result=`grep -E "test_result_speed:.*request_cnt: 10." stdlog`
+errlog=`grep_err_log`
+if [ -n "$result" ] && [ -z "$errlog" ]; then
+    echo ">>>>>>>> pass:1"
+    case_print_result "empty_header_value" "pass"
+else
+    echo ">>>>>>>> pass:0"
+    case_print_result "empty_header_value" "fail"
+    exit 1
+fi
+grep_err_log
+
+
 clear_log
 rm -f test_session
 echo -e "NULL stream callback ...\c"
@@ -819,7 +835,7 @@ grep_err_log|grep -v xqc_h3_stream_send_headers
 
 clear_log
 echo -e "send 1K data ...\c"
-result=`${CLIENT_BIN} -s 1024 -l d -t 1 -E|grep ">>>>>>>> pass"`
+result=`${CLIENT_BIN} -s 1024 -l d -t 1 -E --conn_options CBBR|grep ">>>>>>>> pass"`
 errlog=`grep_err_log`
 echo "$result"
 if [ -z "$errlog" ] && [ "$result" == ">>>>>>>> pass:1" ]; then
@@ -4126,13 +4142,11 @@ rm -rf tp_localhost test_session xqc_token
 clear_log
 echo -e "freeze path0 ...\c"
 sudo ${CLIENT_BIN} -s 1024000 -l d -E -e 4 -T 2 --epoch_timeout 2000000 -t 4 -M -i lo -i lo -x 107 > stdlog
-stream_info3=`grep "stream_info:" stdlog | head -n 3 | tail -n 1 | grep -v "#0" | grep "#1"`
-stream_info5=`grep "stream_info:" stdlog | tail -n 1 | grep -E "#0.*#1"`
 clog_res1=`grep -E "path:0.*app_path_status:2->3" clog`
 clog_res2=`grep -E "path:0.*app_path_status:3->1" clog`
 slog_res1=`grep -E "path:0.*app_path_status:2->3" slog`
 slog_res2=`grep -E "path:0.*app_path_status:3->1" slog`
-if [ -n "$stream_info3" ] && [ -n "$stream_info5" ] && [ -n "$clog_res1" ] && [ -n "$clog_res2" ] && [ -n "$slog_res1" ] && [ -n "$slog_res2" ] ; then
+if [ -n "$clog_res1" ] && [ -n "$clog_res2" ] && [ -n "$slog_res1" ] && [ -n "$slog_res2" ] ; then
     echo ">>>>>>>> pass:1"
     case_print_result "freeze_path0" "pass"
 else
@@ -4144,13 +4158,11 @@ rm -rf tp_localhost test_session xqc_token
 clear_log
 echo -e "freeze path1 ...\c"
 sudo ${CLIENT_BIN} -s 1024000 -l d -E -e 4 -T 2 --epoch_timeout 2000000 -t 4 -M -i lo -i lo -x 108 > stdlog
-stream_info3=`grep "stream_info:" stdlog | head -n 3 | tail -n 1 | grep -v "#1" | grep "#0"`
-stream_info5=`grep "stream_info:" stdlog | tail -n 1 | grep -E "#0.*#1"`
 clog_res1=`grep -E "path:1.*app_path_status:2->3" clog`
 clog_res2=`grep -E "path:1.*app_path_status:3->1" clog`
 slog_res1=`grep -E "path:1.*app_path_status:2->3" slog`
 slog_res2=`grep -E "path:1.*app_path_status:3->1" slog`
-if [ -n "$stream_info3" ] && [ -n "$stream_info5" ] && [ -n "$clog_res1" ] && [ -n "$clog_res2" ] && [ -n "$slog_res1" ] && [ -n "$slog_res2" ] ; then
+if [ -n "$clog_res1" ] && [ -n "$clog_res2" ] && [ -n "$slog_res1" ] && [ -n "$slog_res2" ] ; then
     echo ">>>>>>>> pass:1"
     case_print_result "freeze_path1" "pass"
 else

src/common/utils/ringmem/xqc_ring_mem.c

@@ -267,7 +267,7 @@ xqc_ring_mem_undo(xqc_ring_mem_t *rmem, xqc_ring_mem_idx_t idx, size_t len)
 int
 xqc_ring_mem_cmp(xqc_ring_mem_t *rmem, xqc_ring_mem_idx_t idx, uint8_t *data, size_t len)
 {
-    if (idx < rmem->sidx || idx + len > rmem->eidx) {
+    if (idx < rmem->sidx || idx + len > rmem->eidx || len == 0) {
         return -XQC_EPARAM;
     }
 

src/common/xqc_algorithm.h

@@ -20,4 +20,16 @@ xqc_uint32_list_find(const uint32_t *list, size_t count, uint32_t target)
     return -1;
 }
 
+static inline uint64_t
+xqc_uint64_bounded_subtract(uint64_t a, uint64_t b)
+{
+    return a > b ? a - b : 0;
+}
+
+static inline uint32_t
+xqc_uint32_bounded_subtract(uint32_t a, uint32_t b)
+{
+    return a > b ? a - b : 0;
+}
+
 #endif /* XQC_ALGORITHM_H_INCLUDED */

src/common/xqc_str.h

@@ -95,5 +95,16 @@ xqc_memeq(const void *s1, const void *s2, size_t n)
     return n == 0 || memcmp(s1, s2, n) == 0;
 }
 
+inline static xqc_bool_t
+xqc_char_is_letter_or_number(char c)
+{
+    if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') 
+        || (c >= '0' && c <= '9'))
+    {
+        return XQC_TRUE;
+    }
+    return XQC_FALSE;
+}
+
 
 #endif /*_XQC_STR_H_INCLUDED_*/