4 * Copyright (C) 1991-1998, Thomas G. Lane.
5 * Copyright (C) 2012, D. R. Commander.
6 * This file is part of the Independent JPEG Group's software.
7 * For conditions of distribution and use, see the accompanying README file.
9 * This file contains routines to decode JPEG datastream markers.
10 * Most of the complexity arises from our desire to support input
11 * suspension: if not all of the data for a marker is available,
12 * we must exit back to the application. On resumption, we reprocess
16 #define JPEG_INTERNALS
21 typedef enum { /* JPEG marker codes */
92 struct jpeg_marker_reader pub; /* public fields */
94 /* Application-overridable marker processing methods */
95 jpeg_marker_parser_method process_COM;
96 jpeg_marker_parser_method process_APPn[16];
98 /* Limit on marker data length to save for each marker type */
99 unsigned int length_limit_COM;
100 unsigned int length_limit_APPn[16];
102 /* Status of COM/APPn marker saving */
103 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
104 unsigned int bytes_read; /* data bytes read so far in marker */
105 /* Note: cur_marker is not linked into marker_list until it's all read. */
108 typedef my_marker_reader * my_marker_ptr;
112 * Macros for fetching data from the data source module.
114 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
115 * the current restart point; we update them only when we have reached a
116 * suitable place to restart if a suspension occurs.
119 /* Declare and initialize local copies of input pointer/count */
120 #define INPUT_VARS(cinfo) \
121 struct jpeg_source_mgr * datasrc = (cinfo)->src; \
122 const JOCTET * next_input_byte = datasrc->next_input_byte; \
123 size_t bytes_in_buffer = datasrc->bytes_in_buffer
125 /* Unload the local copies --- do this only at a restart boundary */
126 #define INPUT_SYNC(cinfo) \
127 ( datasrc->next_input_byte = next_input_byte, \
128 datasrc->bytes_in_buffer = bytes_in_buffer )
130 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
131 #define INPUT_RELOAD(cinfo) \
132 ( next_input_byte = datasrc->next_input_byte, \
133 bytes_in_buffer = datasrc->bytes_in_buffer )
135 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
136 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
137 * but we must reload the local copies after a successful fill.
139 #define MAKE_BYTE_AVAIL(cinfo,action) \
140 if (bytes_in_buffer == 0) { \
141 if (! (*datasrc->fill_input_buffer) (cinfo)) \
143 INPUT_RELOAD(cinfo); \
146 /* Read a byte into variable V.
147 * If must suspend, take the specified action (typically "return FALSE").
149 #define INPUT_BYTE(cinfo,V,action) \
150 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
152 V = GETJOCTET(*next_input_byte++); )
154 /* As above, but read two bytes interpreted as an unsigned 16-bit integer.
155 * V should be declared unsigned int or perhaps INT32.
157 #define INPUT_2BYTES(cinfo,V,action) \
158 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
160 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
161 MAKE_BYTE_AVAIL(cinfo,action); \
163 V += GETJOCTET(*next_input_byte++); )
167 * Routines to process JPEG markers.
169 * Entry condition: JPEG marker itself has been read and its code saved
170 * in cinfo->unread_marker; input restart point is just after the marker.
172 * Exit: if return TRUE, have read and processed any parameters, and have
173 * updated the restart point to point after the parameters.
174 * If return FALSE, was forced to suspend before reaching end of
175 * marker parameters; restart point has not been moved. Same routine
176 * will be called again after application supplies more input data.
178 * This approach to suspension assumes that all of a marker's parameters
179 * can fit into a single input bufferload. This should hold for "normal"
180 * markers. Some COM/APPn markers might have large parameter segments
181 * that might not fit. If we are simply dropping such a marker, we use
182 * skip_input_data to get past it, and thereby put the problem on the
183 * source manager's shoulders. If we are saving the marker's contents
184 * into memory, we use a slightly different convention: when forced to
185 * suspend, the marker processor updates the restart point to the end of
186 * what it's consumed (ie, the end of the buffer) before returning FALSE.
187 * On resumption, cinfo->unread_marker still contains the marker code,
188 * but the data source will point to the next chunk of marker data.
189 * The marker processor must retain internal state to deal with this.
191 * Note that we don't bother to avoid duplicate trace messages if a
192 * suspension occurs within marker parameters. Other side effects
198 get_soi (j_decompress_ptr cinfo)
199 /* Process an SOI marker */
203 TRACEMS(cinfo, 1, JTRC_SOI);
205 if (cinfo->marker->saw_SOI)
206 ERREXIT(cinfo, JERR_SOI_DUPLICATE);
208 /* Reset all parameters that are defined to be reset by SOI */
210 for (i = 0; i < NUM_ARITH_TBLS; i++) {
211 cinfo->arith_dc_L[i] = 0;
212 cinfo->arith_dc_U[i] = 1;
213 cinfo->arith_ac_K[i] = 5;
215 cinfo->restart_interval = 0;
217 /* Set initial assumptions for colorspace etc */
219 cinfo->jpeg_color_space = JCS_UNKNOWN;
220 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
222 cinfo->saw_JFIF_marker = FALSE;
223 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
224 cinfo->JFIF_minor_version = 1;
225 cinfo->density_unit = 0;
226 cinfo->X_density = 1;
227 cinfo->Y_density = 1;
228 cinfo->saw_Adobe_marker = FALSE;
229 cinfo->Adobe_transform = 0;
231 cinfo->marker->saw_SOI = TRUE;
238 get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
239 /* Process a SOFn marker */
243 jpeg_component_info * compptr;
246 cinfo->progressive_mode = is_prog;
247 cinfo->arith_code = is_arith;
249 INPUT_2BYTES(cinfo, length, return FALSE);
251 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
252 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
253 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
254 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
258 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
259 (int) cinfo->image_width, (int) cinfo->image_height,
260 cinfo->num_components);
262 if (cinfo->marker->saw_SOF)
263 ERREXIT(cinfo, JERR_SOF_DUPLICATE);
265 /* We don't support files in which the image height is initially specified */
266 /* as 0 and is later redefined by DNL. As long as we have to check that, */
267 /* might as well have a general sanity check. */
268 if (cinfo->image_height <= 0 || cinfo->image_width <= 0
269 || cinfo->num_components <= 0)
270 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
272 if (length != (cinfo->num_components * 3))
273 ERREXIT(cinfo, JERR_BAD_LENGTH);
275 if (cinfo->comp_info == NULL) /* do only once, even if suspend */
276 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
277 ((j_common_ptr) cinfo, JPOOL_IMAGE,
278 cinfo->num_components * SIZEOF(jpeg_component_info));
280 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
282 compptr->component_index = ci;
283 INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
284 INPUT_BYTE(cinfo, c, return FALSE);
285 compptr->h_samp_factor = (c >> 4) & 15;
286 compptr->v_samp_factor = (c ) & 15;
287 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
289 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
290 compptr->component_id, compptr->h_samp_factor,
291 compptr->v_samp_factor, compptr->quant_tbl_no);
294 cinfo->marker->saw_SOF = TRUE;
302 get_sos (j_decompress_ptr cinfo)
303 /* Process a SOS marker */
307 jpeg_component_info * compptr;
310 if (! cinfo->marker->saw_SOF)
311 ERREXIT(cinfo, JERR_SOS_NO_SOF);
313 INPUT_2BYTES(cinfo, length, return FALSE);
315 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
317 TRACEMS1(cinfo, 1, JTRC_SOS, n);
319 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
320 ERREXIT(cinfo, JERR_BAD_LENGTH);
322 cinfo->comps_in_scan = n;
324 /* Collect the component-spec parameters */
326 for (i = 0; i < MAX_COMPS_IN_SCAN; i++)
327 cinfo->cur_comp_info[i] = NULL;
329 for (i = 0; i < n; i++) {
330 INPUT_BYTE(cinfo, cc, return FALSE);
331 INPUT_BYTE(cinfo, c, return FALSE);
333 for (ci = 0, compptr = cinfo->comp_info;
334 ci < cinfo->num_components && ci < MAX_COMPS_IN_SCAN;
336 if (cc == compptr->component_id && !cinfo->cur_comp_info[ci])
340 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
344 cinfo->cur_comp_info[i] = compptr;
345 compptr->dc_tbl_no = (c >> 4) & 15;
346 compptr->ac_tbl_no = (c ) & 15;
348 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
349 compptr->dc_tbl_no, compptr->ac_tbl_no);
352 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
353 INPUT_BYTE(cinfo, c, return FALSE);
355 INPUT_BYTE(cinfo, c, return FALSE);
357 INPUT_BYTE(cinfo, c, return FALSE);
358 cinfo->Ah = (c >> 4) & 15;
359 cinfo->Al = (c ) & 15;
361 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
362 cinfo->Ah, cinfo->Al);
364 /* Prepare to scan data & restart markers */
365 cinfo->marker->next_restart_num = 0;
367 /* Count another SOS marker */
368 cinfo->input_scan_number++;
375 #ifdef D_ARITH_CODING_SUPPORTED
378 get_dac (j_decompress_ptr cinfo)
379 /* Process a DAC marker */
385 INPUT_2BYTES(cinfo, length, return FALSE);
389 INPUT_BYTE(cinfo, index, return FALSE);
390 INPUT_BYTE(cinfo, val, return FALSE);
394 TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
396 if (index < 0 || index >= (2*NUM_ARITH_TBLS))
397 ERREXIT1(cinfo, JERR_DAC_INDEX, index);
399 if (index >= NUM_ARITH_TBLS) { /* define AC table */
400 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
401 } else { /* define DC table */
402 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
403 cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
404 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
405 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
410 ERREXIT(cinfo, JERR_BAD_LENGTH);
416 #else /* ! D_ARITH_CODING_SUPPORTED */
418 #define get_dac(cinfo) skip_variable(cinfo)
420 #endif /* D_ARITH_CODING_SUPPORTED */
424 get_dht (j_decompress_ptr cinfo)
425 /* Process a DHT marker */
434 INPUT_2BYTES(cinfo, length, return FALSE);
437 while (length > 16) {
438 INPUT_BYTE(cinfo, index, return FALSE);
440 TRACEMS1(cinfo, 1, JTRC_DHT, index);
444 for (i = 1; i <= 16; i++) {
445 INPUT_BYTE(cinfo, bits[i], return FALSE);
451 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
452 bits[1], bits[2], bits[3], bits[4],
453 bits[5], bits[6], bits[7], bits[8]);
454 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
455 bits[9], bits[10], bits[11], bits[12],
456 bits[13], bits[14], bits[15], bits[16]);
458 /* Here we just do minimal validation of the counts to avoid walking
459 * off the end of our table space. jdhuff.c will check more carefully.
461 if (count > 256 || ((INT32) count) > length)
462 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
464 for (i = 0; i < count; i++)
465 INPUT_BYTE(cinfo, huffval[i], return FALSE);
469 if (index & 0x10) { /* AC table definition */
471 htblptr = &cinfo->ac_huff_tbl_ptrs[index];
472 } else { /* DC table definition */
473 htblptr = &cinfo->dc_huff_tbl_ptrs[index];
476 if (index < 0 || index >= NUM_HUFF_TBLS)
477 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
479 if (*htblptr == NULL)
480 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
482 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
483 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
487 ERREXIT(cinfo, JERR_BAD_LENGTH);
495 get_dqt (j_decompress_ptr cinfo)
496 /* Process a DQT marker */
501 JQUANT_TBL *quant_ptr;
504 INPUT_2BYTES(cinfo, length, return FALSE);
508 INPUT_BYTE(cinfo, n, return FALSE);
512 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
514 if (n >= NUM_QUANT_TBLS)
515 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
517 if (cinfo->quant_tbl_ptrs[n] == NULL)
518 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
519 quant_ptr = cinfo->quant_tbl_ptrs[n];
521 for (i = 0; i < DCTSIZE2; i++) {
523 INPUT_2BYTES(cinfo, tmp, return FALSE);
525 INPUT_BYTE(cinfo, tmp, return FALSE);
526 /* We convert the zigzag-order table to natural array order. */
527 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
530 if (cinfo->err->trace_level >= 2) {
531 for (i = 0; i < DCTSIZE2; i += 8) {
532 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
533 quant_ptr->quantval[i], quant_ptr->quantval[i+1],
534 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
535 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
536 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
540 length -= DCTSIZE2+1;
541 if (prec) length -= DCTSIZE2;
545 ERREXIT(cinfo, JERR_BAD_LENGTH);
553 get_dri (j_decompress_ptr cinfo)
554 /* Process a DRI marker */
560 INPUT_2BYTES(cinfo, length, return FALSE);
563 ERREXIT(cinfo, JERR_BAD_LENGTH);
565 INPUT_2BYTES(cinfo, tmp, return FALSE);
567 TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
569 cinfo->restart_interval = tmp;
577 * Routines for processing APPn and COM markers.
578 * These are either saved in memory or discarded, per application request.
579 * APP0 and APP14 are specially checked to see if they are
580 * JFIF and Adobe markers, respectively.
583 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
584 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
585 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
589 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
590 unsigned int datalen, INT32 remaining)
591 /* Examine first few bytes from an APP0.
592 * Take appropriate action if it is a JFIF marker.
593 * datalen is # of bytes at data[], remaining is length of rest of marker data.
596 INT32 totallen = (INT32) datalen + remaining;
598 if (datalen >= APP0_DATA_LEN &&
599 GETJOCTET(data[0]) == 0x4A &&
600 GETJOCTET(data[1]) == 0x46 &&
601 GETJOCTET(data[2]) == 0x49 &&
602 GETJOCTET(data[3]) == 0x46 &&
603 GETJOCTET(data[4]) == 0) {
604 /* Found JFIF APP0 marker: save info */
605 cinfo->saw_JFIF_marker = TRUE;
606 cinfo->JFIF_major_version = GETJOCTET(data[5]);
607 cinfo->JFIF_minor_version = GETJOCTET(data[6]);
608 cinfo->density_unit = GETJOCTET(data[7]);
609 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
610 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
612 * Major version must be 1, anything else signals an incompatible change.
613 * (We used to treat this as an error, but now it's a nonfatal warning,
614 * because some bozo at Hijaak couldn't read the spec.)
615 * Minor version should be 0..2, but process anyway if newer.
617 if (cinfo->JFIF_major_version != 1)
618 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
619 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
620 /* Generate trace messages */
621 TRACEMS5(cinfo, 1, JTRC_JFIF,
622 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
623 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
624 /* Validate thumbnail dimensions and issue appropriate messages */
625 if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
626 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
627 GETJOCTET(data[12]), GETJOCTET(data[13]));
628 totallen -= APP0_DATA_LEN;
630 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
631 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
632 } else if (datalen >= 6 &&
633 GETJOCTET(data[0]) == 0x4A &&
634 GETJOCTET(data[1]) == 0x46 &&
635 GETJOCTET(data[2]) == 0x58 &&
636 GETJOCTET(data[3]) == 0x58 &&
637 GETJOCTET(data[4]) == 0) {
638 /* Found JFIF "JFXX" extension APP0 marker */
639 /* The library doesn't actually do anything with these,
640 * but we try to produce a helpful trace message.
642 switch (GETJOCTET(data[5])) {
644 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
647 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
650 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
653 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
654 GETJOCTET(data[5]), (int) totallen);
658 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
659 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
665 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
666 unsigned int datalen, INT32 remaining)
667 /* Examine first few bytes from an APP14.
668 * Take appropriate action if it is an Adobe marker.
669 * datalen is # of bytes at data[], remaining is length of rest of marker data.
672 unsigned int version, flags0, flags1, transform;
674 if (datalen >= APP14_DATA_LEN &&
675 GETJOCTET(data[0]) == 0x41 &&
676 GETJOCTET(data[1]) == 0x64 &&
677 GETJOCTET(data[2]) == 0x6F &&
678 GETJOCTET(data[3]) == 0x62 &&
679 GETJOCTET(data[4]) == 0x65) {
680 /* Found Adobe APP14 marker */
681 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
682 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
683 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
684 transform = GETJOCTET(data[11]);
685 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
686 cinfo->saw_Adobe_marker = TRUE;
687 cinfo->Adobe_transform = (UINT8) transform;
689 /* Start of APP14 does not match "Adobe", or too short */
690 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
696 get_interesting_appn (j_decompress_ptr cinfo)
697 /* Process an APP0 or APP14 marker without saving it */
700 JOCTET b[APPN_DATA_LEN];
701 unsigned int i, numtoread;
704 INPUT_2BYTES(cinfo, length, return FALSE);
707 /* get the interesting part of the marker data */
708 if (length >= APPN_DATA_LEN)
709 numtoread = APPN_DATA_LEN;
711 numtoread = (unsigned int) length;
714 for (i = 0; i < numtoread; i++)
715 INPUT_BYTE(cinfo, b[i], return FALSE);
719 switch (cinfo->unread_marker) {
721 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
724 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
727 /* can't get here unless jpeg_save_markers chooses wrong processor */
728 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
732 /* skip any remaining data -- could be lots */
735 (*cinfo->src->skip_input_data) (cinfo, (long) length);
741 #ifdef SAVE_MARKERS_SUPPORTED
744 save_marker (j_decompress_ptr cinfo)
745 /* Save an APPn or COM marker into the marker list */
747 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
748 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
749 unsigned int bytes_read, data_length;
754 if (cur_marker == NULL) {
755 /* begin reading a marker */
756 INPUT_2BYTES(cinfo, length, return FALSE);
758 if (length >= 0) { /* watch out for bogus length word */
759 /* figure out how much we want to save */
761 if (cinfo->unread_marker == (int) M_COM)
762 limit = marker->length_limit_COM;
764 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
765 if ((unsigned int) length < limit)
766 limit = (unsigned int) length;
767 /* allocate and initialize the marker item */
768 cur_marker = (jpeg_saved_marker_ptr)
769 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
770 SIZEOF(struct jpeg_marker_struct) + limit);
771 cur_marker->next = NULL;
772 cur_marker->marker = (UINT8) cinfo->unread_marker;
773 cur_marker->original_length = (unsigned int) length;
774 cur_marker->data_length = limit;
775 /* data area is just beyond the jpeg_marker_struct */
776 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
777 marker->cur_marker = cur_marker;
778 marker->bytes_read = 0;
782 /* deal with bogus length word */
783 bytes_read = data_length = 0;
787 /* resume reading a marker */
788 bytes_read = marker->bytes_read;
789 data_length = cur_marker->data_length;
790 data = cur_marker->data + bytes_read;
793 while (bytes_read < data_length) {
794 INPUT_SYNC(cinfo); /* move the restart point to here */
795 marker->bytes_read = bytes_read;
796 /* If there's not at least one byte in buffer, suspend */
797 MAKE_BYTE_AVAIL(cinfo, return FALSE);
798 /* Copy bytes with reasonable rapidity */
799 while (bytes_read < data_length && bytes_in_buffer > 0) {
800 *data++ = *next_input_byte++;
806 /* Done reading what we want to read */
807 if (cur_marker != NULL) { /* will be NULL if bogus length word */
808 /* Add new marker to end of list */
809 if (cinfo->marker_list == NULL) {
810 cinfo->marker_list = cur_marker;
812 jpeg_saved_marker_ptr prev = cinfo->marker_list;
813 while (prev->next != NULL)
815 prev->next = cur_marker;
817 /* Reset pointer & calc remaining data length */
818 data = cur_marker->data;
819 length = cur_marker->original_length - data_length;
821 /* Reset to initial state for next marker */
822 marker->cur_marker = NULL;
824 /* Process the marker if interesting; else just make a generic trace msg */
825 switch (cinfo->unread_marker) {
827 examine_app0(cinfo, data, data_length, length);
830 examine_app14(cinfo, data, data_length, length);
833 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
834 (int) (data_length + length));
838 /* skip any remaining data -- could be lots */
839 INPUT_SYNC(cinfo); /* do before skip_input_data */
841 (*cinfo->src->skip_input_data) (cinfo, (long) length);
846 #endif /* SAVE_MARKERS_SUPPORTED */
850 skip_variable (j_decompress_ptr cinfo)
851 /* Skip over an unknown or uninteresting variable-length marker */
856 INPUT_2BYTES(cinfo, length, return FALSE);
859 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
861 INPUT_SYNC(cinfo); /* do before skip_input_data */
863 (*cinfo->src->skip_input_data) (cinfo, (long) length);
870 * Find the next JPEG marker, save it in cinfo->unread_marker.
871 * Returns FALSE if had to suspend before reaching a marker;
872 * in that case cinfo->unread_marker is unchanged.
874 * Note that the result might not be a valid marker code,
875 * but it will never be 0 or FF.
879 next_marker (j_decompress_ptr cinfo)
885 INPUT_BYTE(cinfo, c, return FALSE);
886 /* Skip any non-FF bytes.
887 * This may look a bit inefficient, but it will not occur in a valid file.
888 * We sync after each discarded byte so that a suspending data source
889 * can discard the byte from its buffer.
892 cinfo->marker->discarded_bytes++;
894 INPUT_BYTE(cinfo, c, return FALSE);
896 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
897 * pad bytes, so don't count them in discarded_bytes. We assume there
898 * will not be so many consecutive FF bytes as to overflow a suspending
899 * data source's input buffer.
902 INPUT_BYTE(cinfo, c, return FALSE);
905 break; /* found a valid marker, exit loop */
906 /* Reach here if we found a stuffed-zero data sequence (FF/00).
907 * Discard it and loop back to try again.
909 cinfo->marker->discarded_bytes += 2;
913 if (cinfo->marker->discarded_bytes != 0) {
914 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
915 cinfo->marker->discarded_bytes = 0;
918 cinfo->unread_marker = c;
926 first_marker (j_decompress_ptr cinfo)
927 /* Like next_marker, but used to obtain the initial SOI marker. */
928 /* For this marker, we do not allow preceding garbage or fill; otherwise,
929 * we might well scan an entire input file before realizing it ain't JPEG.
930 * If an application wants to process non-JFIF files, it must seek to the
931 * SOI before calling the JPEG library.
937 INPUT_BYTE(cinfo, c, return FALSE);
938 INPUT_BYTE(cinfo, c2, return FALSE);
939 if (c != 0xFF || c2 != (int) M_SOI)
940 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
942 cinfo->unread_marker = c2;
950 * Read markers until SOS or EOI.
952 * Returns same codes as are defined for jpeg_consume_input:
953 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
957 read_markers (j_decompress_ptr cinfo)
959 /* Outer loop repeats once for each marker. */
961 /* Collect the marker proper, unless we already did. */
962 /* NB: first_marker() enforces the requirement that SOI appear first. */
963 if (cinfo->unread_marker == 0) {
964 if (! cinfo->marker->saw_SOI) {
965 if (! first_marker(cinfo))
966 return JPEG_SUSPENDED;
968 if (! next_marker(cinfo))
969 return JPEG_SUSPENDED;
972 /* At this point cinfo->unread_marker contains the marker code and the
973 * input point is just past the marker proper, but before any parameters.
974 * A suspension will cause us to return with this state still true.
976 switch (cinfo->unread_marker) {
978 if (! get_soi(cinfo))
979 return JPEG_SUSPENDED;
982 case M_SOF0: /* Baseline */
983 case M_SOF1: /* Extended sequential, Huffman */
984 if (! get_sof(cinfo, FALSE, FALSE))
985 return JPEG_SUSPENDED;
988 case M_SOF2: /* Progressive, Huffman */
989 if (! get_sof(cinfo, TRUE, FALSE))
990 return JPEG_SUSPENDED;
993 case M_SOF9: /* Extended sequential, arithmetic */
994 if (! get_sof(cinfo, FALSE, TRUE))
995 return JPEG_SUSPENDED;
998 case M_SOF10: /* Progressive, arithmetic */
999 if (! get_sof(cinfo, TRUE, TRUE))
1000 return JPEG_SUSPENDED;
1003 /* Currently unsupported SOFn types */
1004 case M_SOF3: /* Lossless, Huffman */
1005 case M_SOF5: /* Differential sequential, Huffman */
1006 case M_SOF6: /* Differential progressive, Huffman */
1007 case M_SOF7: /* Differential lossless, Huffman */
1008 case M_JPG: /* Reserved for JPEG extensions */
1009 case M_SOF11: /* Lossless, arithmetic */
1010 case M_SOF13: /* Differential sequential, arithmetic */
1011 case M_SOF14: /* Differential progressive, arithmetic */
1012 case M_SOF15: /* Differential lossless, arithmetic */
1013 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1017 if (! get_sos(cinfo))
1018 return JPEG_SUSPENDED;
1019 cinfo->unread_marker = 0; /* processed the marker */
1020 return JPEG_REACHED_SOS;
1023 TRACEMS(cinfo, 1, JTRC_EOI);
1024 cinfo->unread_marker = 0; /* processed the marker */
1025 return JPEG_REACHED_EOI;
1028 if (! get_dac(cinfo))
1029 return JPEG_SUSPENDED;
1033 if (! get_dht(cinfo))
1034 return JPEG_SUSPENDED;
1038 if (! get_dqt(cinfo))
1039 return JPEG_SUSPENDED;
1043 if (! get_dri(cinfo))
1044 return JPEG_SUSPENDED;
1063 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1064 cinfo->unread_marker - (int) M_APP0]) (cinfo))
1065 return JPEG_SUSPENDED;
1069 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1070 return JPEG_SUSPENDED;
1073 case M_RST0: /* these are all parameterless */
1082 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1085 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1086 if (! skip_variable(cinfo))
1087 return JPEG_SUSPENDED;
1090 default: /* must be DHP, EXP, JPGn, or RESn */
1091 /* For now, we treat the reserved markers as fatal errors since they are
1092 * likely to be used to signal incompatible JPEG Part 3 extensions.
1093 * Once the JPEG 3 version-number marker is well defined, this code
1096 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1099 /* Successfully processed marker, so reset state variable */
1100 cinfo->unread_marker = 0;
1106 * Read a restart marker, which is expected to appear next in the datastream;
1107 * if the marker is not there, take appropriate recovery action.
1108 * Returns FALSE if suspension is required.
1110 * This is called by the entropy decoder after it has read an appropriate
1111 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1112 * has already read a marker from the data source. Under normal conditions
1113 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1114 * it holds a marker which the decoder will be unable to read past.
1118 read_restart_marker (j_decompress_ptr cinfo)
1120 /* Obtain a marker unless we already did. */
1121 /* Note that next_marker will complain if it skips any data. */
1122 if (cinfo->unread_marker == 0) {
1123 if (! next_marker(cinfo))
1127 if (cinfo->unread_marker ==
1128 ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1129 /* Normal case --- swallow the marker and let entropy decoder continue */
1130 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1131 cinfo->unread_marker = 0;
1133 /* Uh-oh, the restart markers have been messed up. */
1134 /* Let the data source manager determine how to resync. */
1135 if (! (*cinfo->src->resync_to_restart) (cinfo,
1136 cinfo->marker->next_restart_num))
1140 /* Update next-restart state */
1141 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1148 * This is the default resync_to_restart method for data source managers
1149 * to use if they don't have any better approach. Some data source managers
1150 * may be able to back up, or may have additional knowledge about the data
1151 * which permits a more intelligent recovery strategy; such managers would
1152 * presumably supply their own resync method.
1154 * read_restart_marker calls resync_to_restart if it finds a marker other than
1155 * the restart marker it was expecting. (This code is *not* used unless
1156 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1157 * the marker code actually found (might be anything, except 0 or FF).
1158 * The desired restart marker number (0..7) is passed as a parameter.
1159 * This routine is supposed to apply whatever error recovery strategy seems
1160 * appropriate in order to position the input stream to the next data segment.
1161 * Note that cinfo->unread_marker is treated as a marker appearing before
1162 * the current data-source input point; usually it should be reset to zero
1164 * Returns FALSE if suspension is required.
1166 * This implementation is substantially constrained by wanting to treat the
1167 * input as a data stream; this means we can't back up. Therefore, we have
1168 * only the following actions to work with:
1169 * 1. Simply discard the marker and let the entropy decoder resume at next
1171 * 2. Read forward until we find another marker, discarding intervening
1172 * data. (In theory we could look ahead within the current bufferload,
1173 * without having to discard data if we don't find the desired marker.
1174 * This idea is not implemented here, in part because it makes behavior
1175 * dependent on buffer size and chance buffer-boundary positions.)
1176 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1177 * This will cause the entropy decoder to process an empty data segment,
1178 * inserting dummy zeroes, and then we will reprocess the marker.
1180 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1181 * appropriate if the found marker is a future restart marker (indicating
1182 * that we have missed the desired restart marker, probably because it got
1184 * We apply #2 or #3 if the found marker is a restart marker no more than
1185 * two counts behind or ahead of the expected one. We also apply #2 if the
1186 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1187 * If the found marker is a restart marker more than 2 counts away, we do #1
1188 * (too much risk that the marker is erroneous; with luck we will be able to
1189 * resync at some future point).
1190 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1191 * overrunning the end of a scan. An implementation limited to single-scan
1192 * files might find it better to apply #2 for markers other than EOI, since
1193 * any other marker would have to be bogus data in that case.
1197 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1199 int marker = cinfo->unread_marker;
1202 /* Always put up a warning. */
1203 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1205 /* Outer loop handles repeated decision after scanning forward. */
1207 if (marker < (int) M_SOF0)
1208 action = 2; /* invalid marker */
1209 else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1210 action = 3; /* valid non-restart marker */
1212 if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1213 marker == ((int) M_RST0 + ((desired+2) & 7)))
1214 action = 3; /* one of the next two expected restarts */
1215 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1216 marker == ((int) M_RST0 + ((desired-2) & 7)))
1217 action = 2; /* a prior restart, so advance */
1219 action = 1; /* desired restart or too far away */
1221 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1224 /* Discard marker and let entropy decoder resume processing. */
1225 cinfo->unread_marker = 0;
1228 /* Scan to the next marker, and repeat the decision loop. */
1229 if (! next_marker(cinfo))
1231 marker = cinfo->unread_marker;
1234 /* Return without advancing past this marker. */
1235 /* Entropy decoder will be forced to process an empty segment. */
1243 * Reset marker processing state to begin a fresh datastream.
1247 reset_marker_reader (j_decompress_ptr cinfo)
1249 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1251 cinfo->comp_info = NULL; /* until allocated by get_sof */
1252 cinfo->input_scan_number = 0; /* no SOS seen yet */
1253 cinfo->unread_marker = 0; /* no pending marker */
1254 marker->pub.saw_SOI = FALSE; /* set internal state too */
1255 marker->pub.saw_SOF = FALSE;
1256 marker->pub.discarded_bytes = 0;
1257 marker->cur_marker = NULL;
1262 * Initialize the marker reader module.
1263 * This is called only once, when the decompression object is created.
1267 jinit_marker_reader (j_decompress_ptr cinfo)
1269 my_marker_ptr marker;
1272 /* Create subobject in permanent pool */
1273 marker = (my_marker_ptr)
1274 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1275 SIZEOF(my_marker_reader));
1276 cinfo->marker = (struct jpeg_marker_reader *) marker;
1277 /* Initialize public method pointers */
1278 marker->pub.reset_marker_reader = reset_marker_reader;
1279 marker->pub.read_markers = read_markers;
1280 marker->pub.read_restart_marker = read_restart_marker;
1281 /* Initialize COM/APPn processing.
1282 * By default, we examine and then discard APP0 and APP14,
1283 * but simply discard COM and all other APPn.
1285 marker->process_COM = skip_variable;
1286 marker->length_limit_COM = 0;
1287 for (i = 0; i < 16; i++) {
1288 marker->process_APPn[i] = skip_variable;
1289 marker->length_limit_APPn[i] = 0;
1291 marker->process_APPn[0] = get_interesting_appn;
1292 marker->process_APPn[14] = get_interesting_appn;
1293 /* Reset marker processing state */
1294 reset_marker_reader(cinfo);
1299 * Control saving of COM and APPn markers into marker_list.
1302 #ifdef SAVE_MARKERS_SUPPORTED
1305 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1306 unsigned int length_limit)
1308 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1310 jpeg_marker_parser_method processor;
1312 /* Length limit mustn't be larger than what we can allocate
1313 * (should only be a concern in a 16-bit environment).
1315 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1316 if (((long) length_limit) > maxlength)
1317 length_limit = (unsigned int) maxlength;
1319 /* Choose processor routine to use.
1320 * APP0/APP14 have special requirements.
1323 processor = save_marker;
1324 /* If saving APP0/APP14, save at least enough for our internal use. */
1325 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1326 length_limit = APP0_DATA_LEN;
1327 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1328 length_limit = APP14_DATA_LEN;
1330 processor = skip_variable;
1331 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1332 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1333 processor = get_interesting_appn;
1336 if (marker_code == (int) M_COM) {
1337 marker->process_COM = processor;
1338 marker->length_limit_COM = length_limit;
1339 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1340 marker->process_APPn[marker_code - (int) M_APP0] = processor;
1341 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1343 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1346 #endif /* SAVE_MARKERS_SUPPORTED */
1350 * Install a special processing method for COM or APPn markers.
1354 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1355 jpeg_marker_parser_method routine)
1357 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1359 if (marker_code == (int) M_COM)
1360 marker->process_COM = routine;
1361 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1362 marker->process_APPn[marker_code - (int) M_APP0] = routine;
1364 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);