15  * suspension: if not all of the data for a marker is available,
17  * the marker.
25 typedef enum {                  /* JPEG marker codes */
98   /* Application-overridable marker processing methods */
102   /* Limit on marker data length to save for each marker type */
106   /* Status of COM/APPn marker saving */
107   jpeg_saved_marker_ptr cur_marker;     /* NULL if not processing a marker */
108   unsigned int bytes_read;              /* data bytes read so far in marker */
173  * Entry condition: JPEG marker itself has been read and its code saved
174  *   in cinfo->unread_marker; input restart point is just after the marker.
179  *   marker parameters; restart point has not been moved.  Same routine
182  * This approach to suspension assumes that all of a marker's parameters
185  * that might not fit.  If we are simply dropping such a marker, we use
187  * source manager's shoulders.  If we are saving the marker's contents
189  * suspend, the marker processor updates the restart point to the end of
191  * On resumption, cinfo->unread_marker still contains the marker code,
192  * but the data source will point to the next chunk of marker data.
193  * The marker processor must retain internal state to deal with this.
196  * suspension occurs within marker parameters.  Other side effects
203 /* Process an SOI marker */  in get_soi()
209   if (cinfo->marker->saw_SOI)  in get_soi()
235   cinfo->marker->saw_SOI = TRUE;  in get_soi()
243 /* Process a SOFn marker */  in get_sof()
266   if (cinfo->marker->saw_SOF)  in get_sof()
298   cinfo->marker->saw_SOF = TRUE;  in get_sof()
307 /* Process a SOS marker */  in get_sos()
314   if (!cinfo->marker->saw_SOF)  in get_sos()
376   cinfo->marker->next_restart_num = 0;  in get_sos()
378   /* Count another SOS marker */  in get_sos()
390 /* Process a DAC marker */  in get_dac()
436 /* Process a DHT marker */  in get_dht()
510 /* Process a DQT marker */  in get_dqt()
568 /* Process a DRI marker */  in get_dri()
606  * Take appropriate action if it is a JFIF marker.  in examine_app0()
607  * datalen is # of bytes at data[], remaining is length of rest of marker data.  in examine_app0()
618     /* Found JFIF APP0 marker: save info */  in examine_app0()
650     /* Found JFIF "JFXX" extension APP0 marker */  in examine_app0()
679  * Take appropriate action if it is an Adobe marker.  in examine_app14()
680  * datalen is # of bytes at data[], remaining is length of rest of marker data.  in examine_app14()
691     /* Found Adobe APP14 marker */  in examine_app14()
708 /* Process an APP0 or APP14 marker without saving it */  in get_interesting_appn()
718   /* get the interesting part of the marker data */  in get_interesting_appn()
756 /* Save an APPn or COM marker into the marker list */  in save_marker()
758   my_marker_ptr marker = (my_marker_ptr)cinfo->marker;  in save_marker()  local
759   jpeg_saved_marker_ptr cur_marker = marker->cur_marker;  in save_marker()
766     /* begin reading a marker */  in save_marker()
773         limit = marker->length_limit_COM;  in save_marker()
775         limit = marker->length_limit_APPn[cinfo->unread_marker - (int)M_APP0];  in save_marker()
778       /* allocate and initialize the marker item */  in save_marker()
783       cur_marker->marker = (UINT8)cinfo->unread_marker;  in save_marker()
788       marker->cur_marker = cur_marker;  in save_marker()
789       marker->bytes_read = 0;  in save_marker()
798     /* resume reading a marker */  in save_marker()
799     bytes_read = marker->bytes_read;  in save_marker()
806     marker->bytes_read = bytes_read;  in save_marker()
819     /* Add new marker to end of list */  in save_marker()
830   /* Reset to initial state for next marker */  in save_marker()
831   marker->cur_marker = NULL;  in save_marker()
833   /* Process the marker if interesting; else just make a generic trace msg */  in save_marker()
860 /* Skip over an unknown or uninteresting variable-length marker */  in skip_variable()
879  * Find the next JPEG marker, save it in cinfo->unread_marker.
880  * Returns FALSE if had to suspend before reaching a marker;
883  * Note that the result might not be a valid marker code,
901       cinfo->marker->discarded_bytes++;  in next_marker()
914       break;                    /* found a valid marker, exit loop */  in next_marker()
918     cinfo->marker->discarded_bytes += 2;  in next_marker()
922   if (cinfo->marker->discarded_bytes != 0) {  in next_marker()
923     WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);  in next_marker()
924     cinfo->marker->discarded_bytes = 0;  in next_marker()
936 /* Like next_marker, but used to obtain the initial SOI marker. */  in first_marker()
937 /* For this marker, we do not allow preceding garbage or fill; otherwise,  in first_marker()
968   /* Outer loop repeats once for each marker. */  in read_markers()
970     /* Collect the marker proper, unless we already did. */  in read_markers()
973       if (!cinfo->marker->saw_SOI) {  in read_markers()
981     /* At this point cinfo->unread_marker contains the marker code and the  in read_markers()
982      * input point is just past the marker proper, but before any parameters.  in read_markers()
1028       cinfo->unread_marker = 0; /* processed the marker */  in read_markers()
1033       cinfo->unread_marker = 0; /* processed the marker */  in read_markers()
1072       if (!(*((my_marker_ptr)cinfo->marker)->process_APPn[  in read_markers()
1078       if (!(*((my_marker_ptr)cinfo->marker)->process_COM) (cinfo))  in read_markers()
1102        * Once the JPEG 3 version-number marker is well defined, this code  in read_markers()
1108     /* Successfully processed marker, so reset state variable */  in read_markers()
1115  * Read a restart marker, which is expected to appear next in the datastream;
1116  * if the marker is not there, take appropriate recovery action.
1121  * has already read a marker from the data source.  Under normal conditions
1123  * it holds a marker which the decoder will be unable to read past.
1129   /* Obtain a marker unless we already did. */  in read_restart_marker()
1137       ((int)M_RST0 + cinfo->marker->next_restart_num)) {  in read_restart_marker()
1138     /* Normal case --- swallow the marker and let entropy decoder continue */  in read_restart_marker()
1139     TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);  in read_restart_marker()
1145                                            cinfo->marker->next_restart_num))  in read_restart_marker()
1150   cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;  in read_restart_marker()
1163  * read_restart_marker calls resync_to_restart if it finds a marker other than
1164  * the restart marker it was expecting.  (This code is *not* used unless
1166  * the marker code actually found (might be anything, except 0 or FF).
1167  * The desired restart marker number (0..7) is passed as a parameter.
1170  * Note that cinfo->unread_marker is treated as a marker appearing before
1178  *   1. Simply discard the marker and let the entropy decoder resume at next
1180  *   2. Read forward until we find another marker, discarding intervening
1182  *      without having to discard data if we don't find the desired marker.
1185  *   3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1187  *      inserting dummy zeroes, and then we will reprocess the marker.
1189  * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1190  * appropriate if the found marker is a future restart marker (indicating
1191  * that we have missed the desired restart marker, probably because it got
1193  * We apply #2 or #3 if the found marker is a restart marker no more than
1195  * found marker is not a legal JPEG marker code (it's certainly bogus data).
1196  * If the found marker is a restart marker more than 2 counts away, we do #1
1197  * (too much risk that the marker is erroneous; with luck we will be able to
1199  * For any valid non-restart JPEG marker, we apply #3.  This keeps us from
1202  * any other marker would have to be bogus data in that case.
1208   int marker = cinfo->unread_marker;  in jpeg_resync_to_restart()  local
1212   WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);  in jpeg_resync_to_restart()
1216     if (marker < (int)M_SOF0)  in jpeg_resync_to_restart()
1217       action = 2;               /* invalid marker */  in jpeg_resync_to_restart()
1218     else if (marker < (int)M_RST0 || marker > (int)M_RST7)  in jpeg_resync_to_restart()
1219       action = 3;               /* valid non-restart marker */  in jpeg_resync_to_restart()
1221       if (marker == ((int)M_RST0 + ((desired + 1) & 7)) ||  in jpeg_resync_to_restart()
1222           marker == ((int)M_RST0 + ((desired + 2) & 7)))  in jpeg_resync_to_restart()
1224       else if (marker == ((int)M_RST0 + ((desired - 1) & 7)) ||  in jpeg_resync_to_restart()
1225                marker == ((int)M_RST0 + ((desired - 2) & 7)))  in jpeg_resync_to_restart()
1230     TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);  in jpeg_resync_to_restart()
1233       /* Discard marker and let entropy decoder resume processing. */  in jpeg_resync_to_restart()
1237       /* Scan to the next marker, and repeat the decision loop. */  in jpeg_resync_to_restart()
1240       marker = cinfo->unread_marker;  in jpeg_resync_to_restart()
1243       /* Return without advancing past this marker. */  in jpeg_resync_to_restart()
1252  * Reset marker processing state to begin a fresh datastream.
1258   my_marker_ptr marker = (my_marker_ptr)cinfo->marker;  in reset_marker_reader()  local
1262   cinfo->unread_marker = 0;             /* no pending marker */  in reset_marker_reader()
1263   marker->pub.saw_SOI = FALSE;          /* set internal state too */  in reset_marker_reader()
1264   marker->pub.saw_SOF = FALSE;  in reset_marker_reader()
1265   marker->pub.discarded_bytes = 0;  in reset_marker_reader()
1266   marker->cur_marker = NULL;  in reset_marker_reader()
1271  * Initialize the marker reader module.
1278   my_marker_ptr marker;  in jinit_marker_reader()  local
1282   marker = (my_marker_ptr)  in jinit_marker_reader()
1285   cinfo->marker = (struct jpeg_marker_reader *)marker;  in jinit_marker_reader()
1287   marker->pub.reset_marker_reader = reset_marker_reader;  in jinit_marker_reader()
1288   marker->pub.read_markers = read_markers;  in jinit_marker_reader()
1289   marker->pub.read_restart_marker = read_restart_marker;  in jinit_marker_reader()
1294   marker->process_COM = skip_variable;  in jinit_marker_reader()
1295   marker->length_limit_COM = 0;  in jinit_marker_reader()
1297     marker->process_APPn[i] = skip_variable;  in jinit_marker_reader()
1298     marker->length_limit_APPn[i] = 0;  in jinit_marker_reader()
1300   marker->process_APPn[0] = get_interesting_appn;  in jinit_marker_reader()
1301   marker->process_APPn[14] = get_interesting_appn;  in jinit_marker_reader()
1302   /* Reset marker processing state */  in jinit_marker_reader()
1317   my_marker_ptr marker = (my_marker_ptr)cinfo->marker;  in jpeg_save_markers()  local
1346     marker->process_COM = processor;  in jpeg_save_markers()
1347     marker->length_limit_COM = length_limit;  in jpeg_save_markers()
1349     marker->process_APPn[marker_code - (int)M_APP0] = processor;  in jpeg_save_markers()
1350     marker->length_limit_APPn[marker_code - (int)M_APP0] = length_limit;  in jpeg_save_markers()
1366   my_marker_ptr marker = (my_marker_ptr)cinfo->marker;  in jpeg_set_marker_processor()  local
1369     marker->process_COM = routine;  in jpeg_set_marker_processor()
1371     marker->process_APPn[marker_code - (int)M_APP0] = routine;  in jpeg_set_marker_processor()