4 * Copyright (C) 1991-1998, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
8 * This file contains routines to decode JPEG datastream markers.
9 * Most of the complexity arises from our desire to support input
10 * suspension: if not all of the data for a marker is available,
11 * we must exit back to the application. On resumption, we reprocess
15 #define JPEG_INTERNALS
16 #include "jinclude12.h"
17 #include "jpeglib12.h"
20 typedef enum { /* JPEG marker codes */
91 struct jpeg_marker_reader pub; /* public fields */
93 /* Application-overridable marker processing methods */
94 jpeg_marker_parser_method process_COM;
95 jpeg_marker_parser_method process_APPn[16];
97 /* Limit on marker data length to save for each marker type */
98 unsigned int length_limit_COM;
99 unsigned int length_limit_APPn[16];
101 /* Status of COM/APPn marker saving */
102 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
103 unsigned int bytes_read; /* data bytes read so far in marker */
104 /* Note: cur_marker is not linked into marker_list until it's all read. */
107 typedef my_marker_reader * my_marker_ptr;
111 * Macros for fetching data from the data source module.
113 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
114 * the current restart point; we update them only when we have reached a
115 * suitable place to restart if a suspension occurs.
118 /* Declare and initialize local copies of input pointer/count */
119 #define INPUT_VARS(cinfo) \
120 struct jpeg_source_mgr * datasrc = (cinfo)->src; \
121 const JOCTET * next_input_byte = datasrc->next_input_byte; \
122 size_t bytes_in_buffer = datasrc->bytes_in_buffer
124 /* Unload the local copies --- do this only at a restart boundary */
125 #define INPUT_SYNC(cinfo) \
126 ( datasrc->next_input_byte = next_input_byte, \
127 datasrc->bytes_in_buffer = bytes_in_buffer )
129 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
130 #define INPUT_RELOAD(cinfo) \
131 ( next_input_byte = datasrc->next_input_byte, \
132 bytes_in_buffer = datasrc->bytes_in_buffer )
134 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
135 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
136 * but we must reload the local copies after a successful fill.
138 #define MAKE_BYTE_AVAIL(cinfo,action) \
139 if (bytes_in_buffer == 0) { \
140 if (! (*datasrc->fill_input_buffer) (cinfo)) \
142 INPUT_RELOAD(cinfo); \
145 /* Read a byte into variable V.
146 * If must suspend, take the specified action (typically "return FALSE").
148 #define INPUT_BYTE(cinfo,V,action) \
149 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
151 V = GETJOCTET(*next_input_byte++); )
153 /* As above, but read two bytes interpreted as an unsigned 16-bit integer.
154 * V should be declared unsigned int or perhaps INT32.
156 #define INPUT_2BYTES(cinfo,V,action) \
157 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
159 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
160 MAKE_BYTE_AVAIL(cinfo,action); \
162 V += GETJOCTET(*next_input_byte++); )
166 * Routines to process JPEG markers.
168 * Entry condition: JPEG marker itself has been read and its code saved
169 * in cinfo->unread_marker; input restart point is just after the marker.
171 * Exit: if return TRUE, have read and processed any parameters, and have
172 * updated the restart point to point after the parameters.
173 * If return FALSE, was forced to suspend before reaching end of
174 * marker parameters; restart point has not been moved. Same routine
175 * will be called again after application supplies more input data.
177 * This approach to suspension assumes that all of a marker's parameters
178 * can fit into a single input bufferload. This should hold for "normal"
179 * markers. Some COM/APPn markers might have large parameter segments
180 * that might not fit. If we are simply dropping such a marker, we use
181 * skip_input_data to get past it, and thereby put the problem on the
182 * source manager's shoulders. If we are saving the marker's contents
183 * into memory, we use a slightly different convention: when forced to
184 * suspend, the marker processor updates the restart point to the end of
185 * what it's consumed (ie, the end of the buffer) before returning FALSE.
186 * On resumption, cinfo->unread_marker still contains the marker code,
187 * but the data source will point to the next chunk of marker data.
188 * The marker processor must retain internal state to deal with this.
190 * Note that we don't bother to avoid duplicate trace messages if a
191 * suspension occurs within marker parameters. Other side effects
197 get_soi (j_decompress_ptr cinfo)
198 /* Process an SOI marker */
202 TRACEMS(cinfo, 1, JTRC_SOI);
204 if (cinfo->marker->saw_SOI)
205 ERREXIT(cinfo, JERR_SOI_DUPLICATE);
207 /* Reset all parameters that are defined to be reset by SOI */
209 for (i = 0; i < NUM_ARITH_TBLS; i++) {
210 cinfo->arith_dc_L[i] = 0;
211 cinfo->arith_dc_U[i] = 1;
212 cinfo->arith_ac_K[i] = 5;
214 cinfo->restart_interval = 0;
216 /* Set initial assumptions for colorspace etc */
218 cinfo->jpeg_color_space = JCS_UNKNOWN;
219 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
221 cinfo->saw_JFIF_marker = FALSE;
222 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
223 cinfo->JFIF_minor_version = 1;
224 cinfo->density_unit = 0;
225 cinfo->X_density = 1;
226 cinfo->Y_density = 1;
227 cinfo->saw_Adobe_marker = FALSE;
228 cinfo->Adobe_transform = 0;
230 cinfo->marker->saw_SOI = TRUE;
237 get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
238 /* Process a SOFn marker */
242 jpeg_component_info * compptr;
245 cinfo->progressive_mode = is_prog;
246 cinfo->arith_code = is_arith;
248 INPUT_2BYTES(cinfo, length, return FALSE);
250 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
251 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
252 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
253 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
257 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
258 (int) cinfo->image_width, (int) cinfo->image_height,
259 cinfo->num_components);
261 if (cinfo->marker->saw_SOF)
262 ERREXIT(cinfo, JERR_SOF_DUPLICATE);
264 /* We don't support files in which the image height is initially specified */
265 /* as 0 and is later redefined by DNL. As long as we have to check that, */
266 /* might as well have a general sanity check. */
267 if (cinfo->image_height <= 0 || cinfo->image_width <= 0
268 || cinfo->num_components <= 0)
269 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
271 if (length != (cinfo->num_components * 3))
272 ERREXIT(cinfo, JERR_BAD_LENGTH);
274 if (cinfo->comp_info == NULL) /* do only once, even if suspend */
275 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
276 ((j_common_ptr) cinfo, JPOOL_IMAGE,
277 cinfo->num_components * SIZEOF(jpeg_component_info));
279 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
281 compptr->component_index = ci;
282 INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
283 INPUT_BYTE(cinfo, c, return FALSE);
284 compptr->h_samp_factor = (c >> 4) & 15;
285 compptr->v_samp_factor = (c ) & 15;
286 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
288 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
289 compptr->component_id, compptr->h_samp_factor,
290 compptr->v_samp_factor, compptr->quant_tbl_no);
293 cinfo->marker->saw_SOF = TRUE;
301 get_sos (j_decompress_ptr cinfo)
302 /* Process a SOS marker */
306 jpeg_component_info * compptr;
309 if (! cinfo->marker->saw_SOF)
310 ERREXIT(cinfo, JERR_SOS_NO_SOF);
312 INPUT_2BYTES(cinfo, length, return FALSE);
314 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
316 TRACEMS1(cinfo, 1, JTRC_SOS, n);
318 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
319 ERREXIT(cinfo, JERR_BAD_LENGTH);
321 cinfo->comps_in_scan = n;
323 /* Collect the component-spec parameters */
325 for (i = 0; i < n; i++) {
326 INPUT_BYTE(cinfo, cc, return FALSE);
327 INPUT_BYTE(cinfo, c, return FALSE);
329 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
331 if (cc == compptr->component_id)
335 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
339 cinfo->cur_comp_info[i] = compptr;
340 compptr->dc_tbl_no = (c >> 4) & 15;
341 compptr->ac_tbl_no = (c ) & 15;
343 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
344 compptr->dc_tbl_no, compptr->ac_tbl_no);
347 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
348 INPUT_BYTE(cinfo, c, return FALSE);
350 INPUT_BYTE(cinfo, c, return FALSE);
352 INPUT_BYTE(cinfo, c, return FALSE);
353 cinfo->Ah = (c >> 4) & 15;
354 cinfo->Al = (c ) & 15;
356 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
357 cinfo->Ah, cinfo->Al);
359 /* Prepare to scan data & restart markers */
360 cinfo->marker->next_restart_num = 0;
362 /* Count another SOS marker */
363 cinfo->input_scan_number++;
370 #ifdef D_ARITH_CODING_SUPPORTED
373 get_dac (j_decompress_ptr cinfo)
374 /* Process a DAC marker */
380 INPUT_2BYTES(cinfo, length, return FALSE);
384 INPUT_BYTE(cinfo, index, return FALSE);
385 INPUT_BYTE(cinfo, val, return FALSE);
389 TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
391 if (index < 0 || index >= (2*NUM_ARITH_TBLS))
392 ERREXIT1(cinfo, JERR_DAC_INDEX, index);
394 if (index >= NUM_ARITH_TBLS) { /* define AC table */
395 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
396 } else { /* define DC table */
397 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
398 cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
399 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
400 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
405 ERREXIT(cinfo, JERR_BAD_LENGTH);
411 #else /* ! D_ARITH_CODING_SUPPORTED */
413 #define get_dac(cinfo) skip_variable(cinfo)
415 #endif /* D_ARITH_CODING_SUPPORTED */
419 get_dht (j_decompress_ptr cinfo)
420 /* Process a DHT marker */
429 INPUT_2BYTES(cinfo, length, return FALSE);
432 while (length > 16) {
433 INPUT_BYTE(cinfo, index, return FALSE);
435 TRACEMS1(cinfo, 1, JTRC_DHT, index);
439 for (i = 1; i <= 16; i++) {
440 INPUT_BYTE(cinfo, bits[i], return FALSE);
446 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
447 bits[1], bits[2], bits[3], bits[4],
448 bits[5], bits[6], bits[7], bits[8]);
449 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
450 bits[9], bits[10], bits[11], bits[12],
451 bits[13], bits[14], bits[15], bits[16]);
453 /* Here we just do minimal validation of the counts to avoid walking
454 * off the end of our table space. jdhuff.c will check more carefully.
456 if (count > 256 || ((INT32) count) > length) {
457 printf("JERR_BAD_HUFF_TABLE in jdmarker12.c count : %d\n",count);
458 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
460 for (i = 0; i < count; i++)
461 INPUT_BYTE(cinfo, huffval[i], return FALSE);
465 if (index & 0x10) { /* AC table definition */
467 htblptr = &cinfo->ac_huff_tbl_ptrs[index];
468 } else { /* DC table definition */
469 htblptr = &cinfo->dc_huff_tbl_ptrs[index];
472 if (index < 0 || index >= NUM_HUFF_TBLS)
473 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
475 if (*htblptr == NULL)
476 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
478 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
479 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
483 ERREXIT(cinfo, JERR_BAD_LENGTH);
491 get_dqt (j_decompress_ptr cinfo)
492 /* Process a DQT marker */
497 JQUANT_TBL *quant_ptr;
500 INPUT_2BYTES(cinfo, length, return FALSE);
504 INPUT_BYTE(cinfo, n, return FALSE);
508 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
510 if (n >= NUM_QUANT_TBLS)
511 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
513 if (cinfo->quant_tbl_ptrs[n] == NULL)
514 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
515 quant_ptr = cinfo->quant_tbl_ptrs[n];
517 for (i = 0; i < DCTSIZE2; i++) {
519 INPUT_2BYTES(cinfo, tmp, return FALSE);
521 INPUT_BYTE(cinfo, tmp, return FALSE);
522 /* We convert the zigzag-order table to natural array order. */
523 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
526 if (cinfo->err->trace_level >= 2) {
527 for (i = 0; i < DCTSIZE2; i += 8) {
528 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
529 quant_ptr->quantval[i], quant_ptr->quantval[i+1],
530 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
531 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
532 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
536 length -= DCTSIZE2+1;
537 if (prec) length -= DCTSIZE2;
541 ERREXIT(cinfo, JERR_BAD_LENGTH);
549 get_dri (j_decompress_ptr cinfo)
550 /* Process a DRI marker */
556 INPUT_2BYTES(cinfo, length, return FALSE);
559 ERREXIT(cinfo, JERR_BAD_LENGTH);
561 INPUT_2BYTES(cinfo, tmp, return FALSE);
563 TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
565 cinfo->restart_interval = tmp;
573 * Routines for processing APPn and COM markers.
574 * These are either saved in memory or discarded, per application request.
575 * APP0 and APP14 are specially checked to see if they are
576 * JFIF and Adobe markers, respectively.
579 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
580 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
581 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
585 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
586 unsigned int datalen, INT32 remaining)
587 /* Examine first few bytes from an APP0.
588 * Take appropriate action if it is a JFIF marker.
589 * datalen is # of bytes at data[], remaining is length of rest of marker data.
592 INT32 totallen = (INT32) datalen + remaining;
594 if (datalen >= APP0_DATA_LEN &&
595 GETJOCTET(data[0]) == 0x4A &&
596 GETJOCTET(data[1]) == 0x46 &&
597 GETJOCTET(data[2]) == 0x49 &&
598 GETJOCTET(data[3]) == 0x46 &&
599 GETJOCTET(data[4]) == 0) {
600 /* Found JFIF APP0 marker: save info */
601 cinfo->saw_JFIF_marker = TRUE;
602 cinfo->JFIF_major_version = GETJOCTET(data[5]);
603 cinfo->JFIF_minor_version = GETJOCTET(data[6]);
604 cinfo->density_unit = GETJOCTET(data[7]);
605 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
606 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
608 * Major version must be 1, anything else signals an incompatible change.
609 * (We used to treat this as an error, but now it's a nonfatal warning,
610 * because some bozo at Hijaak couldn't read the spec.)
611 * Minor version should be 0..2, but process anyway if newer.
613 if (cinfo->JFIF_major_version != 1)
614 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
615 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
616 /* Generate trace messages */
617 TRACEMS5(cinfo, 1, JTRC_JFIF,
618 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
619 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
620 /* Validate thumbnail dimensions and issue appropriate messages */
621 if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
622 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
623 GETJOCTET(data[12]), GETJOCTET(data[13]));
624 totallen -= APP0_DATA_LEN;
626 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
627 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
628 } else if (datalen >= 6 &&
629 GETJOCTET(data[0]) == 0x4A &&
630 GETJOCTET(data[1]) == 0x46 &&
631 GETJOCTET(data[2]) == 0x58 &&
632 GETJOCTET(data[3]) == 0x58 &&
633 GETJOCTET(data[4]) == 0) {
634 /* Found JFIF "JFXX" extension APP0 marker */
635 /* The library doesn't actually do anything with these,
636 * but we try to produce a helpful trace message.
638 switch (GETJOCTET(data[5])) {
640 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
643 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
646 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
649 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
650 GETJOCTET(data[5]), (int) totallen);
654 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
655 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
661 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
662 unsigned int datalen, INT32 remaining)
663 /* Examine first few bytes from an APP14.
664 * Take appropriate action if it is an Adobe marker.
665 * datalen is # of bytes at data[], remaining is length of rest of marker data.
668 unsigned int version, flags0, flags1, transform;
670 if (datalen >= APP14_DATA_LEN &&
671 GETJOCTET(data[0]) == 0x41 &&
672 GETJOCTET(data[1]) == 0x64 &&
673 GETJOCTET(data[2]) == 0x6F &&
674 GETJOCTET(data[3]) == 0x62 &&
675 GETJOCTET(data[4]) == 0x65) {
676 /* Found Adobe APP14 marker */
677 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
678 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
679 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
680 transform = GETJOCTET(data[11]);
681 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
682 cinfo->saw_Adobe_marker = TRUE;
683 cinfo->Adobe_transform = (UINT8) transform;
685 /* Start of APP14 does not match "Adobe", or too short */
686 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
692 get_interesting_appn (j_decompress_ptr cinfo)
693 /* Process an APP0 or APP14 marker without saving it */
696 JOCTET b[APPN_DATA_LEN];
697 unsigned int i, numtoread;
700 INPUT_2BYTES(cinfo, length, return FALSE);
703 /* get the interesting part of the marker data */
704 if (length >= APPN_DATA_LEN)
705 numtoread = APPN_DATA_LEN;
707 numtoread = (unsigned int) length;
710 for (i = 0; i < numtoread; i++)
711 INPUT_BYTE(cinfo, b[i], return FALSE);
715 switch (cinfo->unread_marker) {
717 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
720 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
723 /* can't get here unless jpeg_save_markers chooses wrong processor */
724 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
728 /* skip any remaining data -- could be lots */
731 (*cinfo->src->skip_input_data) (cinfo, (long) length);
737 #ifdef SAVE_MARKERS_SUPPORTED
740 save_marker (j_decompress_ptr cinfo)
741 /* Save an APPn or COM marker into the marker list */
743 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
744 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
745 unsigned int bytes_read, data_length;
750 if (cur_marker == NULL) {
751 /* begin reading a marker */
752 INPUT_2BYTES(cinfo, length, return FALSE);
754 if (length >= 0) { /* watch out for bogus length word */
755 /* figure out how much we want to save */
757 if (cinfo->unread_marker == (int) M_COM)
758 limit = marker->length_limit_COM;
760 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
761 if ((unsigned int) length < limit)
762 limit = (unsigned int) length;
763 /* allocate and initialize the marker item */
764 cur_marker = (jpeg_saved_marker_ptr)
765 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
766 SIZEOF(struct jpeg_marker_struct) + limit);
767 cur_marker->next = NULL;
768 cur_marker->marker = (UINT8) cinfo->unread_marker;
769 cur_marker->original_length = (unsigned int) length;
770 cur_marker->data_length = limit;
771 /* data area is just beyond the jpeg_marker_struct */
772 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
773 marker->cur_marker = cur_marker;
774 marker->bytes_read = 0;
778 /* deal with bogus length word */
779 bytes_read = data_length = 0;
783 /* resume reading a marker */
784 bytes_read = marker->bytes_read;
785 data_length = cur_marker->data_length;
786 data = cur_marker->data + bytes_read;
789 while (bytes_read < data_length) {
790 INPUT_SYNC(cinfo); /* move the restart point to here */
791 marker->bytes_read = bytes_read;
792 /* If there's not at least one byte in buffer, suspend */
793 MAKE_BYTE_AVAIL(cinfo, return FALSE);
794 /* Copy bytes with reasonable rapidity */
795 while (bytes_read < data_length && bytes_in_buffer > 0) {
796 *data++ = *next_input_byte++;
802 /* Done reading what we want to read */
803 if (cur_marker != NULL) { /* will be NULL if bogus length word */
804 /* Add new marker to end of list */
805 if (cinfo->marker_list == NULL) {
806 cinfo->marker_list = cur_marker;
808 jpeg_saved_marker_ptr prev = cinfo->marker_list;
809 while (prev->next != NULL)
811 prev->next = cur_marker;
813 /* Reset pointer & calc remaining data length */
814 data = cur_marker->data;
815 length = cur_marker->original_length - data_length;
817 /* Reset to initial state for next marker */
818 marker->cur_marker = NULL;
820 /* Process the marker if interesting; else just make a generic trace msg */
821 switch (cinfo->unread_marker) {
823 examine_app0(cinfo, data, data_length, length);
826 examine_app14(cinfo, data, data_length, length);
829 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
830 (int) (data_length + length));
834 /* skip any remaining data -- could be lots */
835 INPUT_SYNC(cinfo); /* do before skip_input_data */
837 (*cinfo->src->skip_input_data) (cinfo, (long) length);
842 #endif /* SAVE_MARKERS_SUPPORTED */
846 skip_variable (j_decompress_ptr cinfo)
847 /* Skip over an unknown or uninteresting variable-length marker */
852 INPUT_2BYTES(cinfo, length, return FALSE);
855 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
857 INPUT_SYNC(cinfo); /* do before skip_input_data */
859 (*cinfo->src->skip_input_data) (cinfo, (long) length);
866 * Find the next JPEG marker, save it in cinfo->unread_marker.
867 * Returns FALSE if had to suspend before reaching a marker;
868 * in that case cinfo->unread_marker is unchanged.
870 * Note that the result might not be a valid marker code,
871 * but it will never be 0 or FF.
875 next_marker (j_decompress_ptr cinfo)
881 INPUT_BYTE(cinfo, c, return FALSE);
882 /* Skip any non-FF bytes.
883 * This may look a bit inefficient, but it will not occur in a valid file.
884 * We sync after each discarded byte so that a suspending data source
885 * can discard the byte from its buffer.
888 cinfo->marker->discarded_bytes++;
890 INPUT_BYTE(cinfo, c, return FALSE);
892 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
893 * pad bytes, so don't count them in discarded_bytes. We assume there
894 * will not be so many consecutive FF bytes as to overflow a suspending
895 * data source's input buffer.
898 INPUT_BYTE(cinfo, c, return FALSE);
901 break; /* found a valid marker, exit loop */
902 /* Reach here if we found a stuffed-zero data sequence (FF/00).
903 * Discard it and loop back to try again.
905 cinfo->marker->discarded_bytes += 2;
909 if (cinfo->marker->discarded_bytes != 0) {
910 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
911 cinfo->marker->discarded_bytes = 0;
914 cinfo->unread_marker = c;
922 first_marker (j_decompress_ptr cinfo)
923 /* Like next_marker, but used to obtain the initial SOI marker. */
924 /* For this marker, we do not allow preceding garbage or fill; otherwise,
925 * we might well scan an entire input file before realizing it ain't JPEG.
926 * If an application wants to process non-JFIF files, it must seek to the
927 * SOI before calling the JPEG library.
933 INPUT_BYTE(cinfo, c, return FALSE);
934 INPUT_BYTE(cinfo, c2, return FALSE);
935 if (c != 0xFF || c2 != (int) M_SOI)
936 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
938 cinfo->unread_marker = c2;
946 * Read markers until SOS or EOI.
948 * Returns same codes as are defined for jpeg_consume_input:
949 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
953 read_markers (j_decompress_ptr cinfo)
955 /* Outer loop repeats once for each marker. */
957 /* Collect the marker proper, unless we already did. */
958 /* NB: first_marker() enforces the requirement that SOI appear first. */
959 if (cinfo->unread_marker == 0) {
960 if (! cinfo->marker->saw_SOI) {
961 if (! first_marker(cinfo))
962 return JPEG_SUSPENDED;
964 if (! next_marker(cinfo))
965 return JPEG_SUSPENDED;
968 /* At this point cinfo->unread_marker contains the marker code and the
969 * input point is just past the marker proper, but before any parameters.
970 * A suspension will cause us to return with this state still true.
972 switch (cinfo->unread_marker) {
974 if (! get_soi(cinfo))
975 return JPEG_SUSPENDED;
978 case M_SOF0: /* Baseline */
979 case M_SOF1: /* Extended sequential, Huffman */
980 if (! get_sof(cinfo, FALSE, FALSE))
981 return JPEG_SUSPENDED;
984 case M_SOF2: /* Progressive, Huffman */
985 if (! get_sof(cinfo, TRUE, FALSE))
986 return JPEG_SUSPENDED;
989 case M_SOF9: /* Extended sequential, arithmetic */
990 if (! get_sof(cinfo, FALSE, TRUE))
991 return JPEG_SUSPENDED;
994 case M_SOF10: /* Progressive, arithmetic */
995 if (! get_sof(cinfo, TRUE, TRUE))
996 return JPEG_SUSPENDED;
999 /* Currently unsupported SOFn types */
1000 case M_SOF3: /* Lossless, Huffman */
1001 case M_SOF5: /* Differential sequential, Huffman */
1002 case M_SOF6: /* Differential progressive, Huffman */
1003 case M_SOF7: /* Differential lossless, Huffman */
1004 case M_JPG: /* Reserved for JPEG extensions */
1005 case M_SOF11: /* Lossless, arithmetic */
1006 case M_SOF13: /* Differential sequential, arithmetic */
1007 case M_SOF14: /* Differential progressive, arithmetic */
1008 case M_SOF15: /* Differential lossless, arithmetic */
1009 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1013 if (! get_sos(cinfo))
1014 return JPEG_SUSPENDED;
1015 cinfo->unread_marker = 0; /* processed the marker */
1016 return JPEG_REACHED_SOS;
1019 TRACEMS(cinfo, 1, JTRC_EOI);
1020 cinfo->unread_marker = 0; /* processed the marker */
1021 return JPEG_REACHED_EOI;
1024 if (! get_dac(cinfo))
1025 return JPEG_SUSPENDED;
1029 if (! get_dht(cinfo))
1030 return JPEG_SUSPENDED;
1034 if (! get_dqt(cinfo))
1035 return JPEG_SUSPENDED;
1039 if (! get_dri(cinfo))
1040 return JPEG_SUSPENDED;
1059 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1060 cinfo->unread_marker - (int) M_APP0]) (cinfo))
1061 return JPEG_SUSPENDED;
1065 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1066 return JPEG_SUSPENDED;
1069 case M_RST0: /* these are all parameterless */
1078 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1081 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1082 if (! skip_variable(cinfo))
1083 return JPEG_SUSPENDED;
1086 default: /* must be DHP, EXP, JPGn, or RESn */
1087 /* For now, we treat the reserved markers as fatal errors since they are
1088 * likely to be used to signal incompatible JPEG Part 3 extensions.
1089 * Once the JPEG 3 version-number marker is well defined, this code
1092 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1095 /* Successfully processed marker, so reset state variable */
1096 cinfo->unread_marker = 0;
1102 * Read a restart marker, which is expected to appear next in the datastream;
1103 * if the marker is not there, take appropriate recovery action.
1104 * Returns FALSE if suspension is required.
1106 * This is called by the entropy decoder after it has read an appropriate
1107 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1108 * has already read a marker from the data source. Under normal conditions
1109 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1110 * it holds a marker which the decoder will be unable to read past.
1114 read_restart_marker (j_decompress_ptr cinfo)
1116 /* Obtain a marker unless we already did. */
1117 /* Note that next_marker will complain if it skips any data. */
1118 if (cinfo->unread_marker == 0) {
1119 if (! next_marker(cinfo))
1123 if (cinfo->unread_marker ==
1124 ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1125 /* Normal case --- swallow the marker and let entropy decoder continue */
1126 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1127 cinfo->unread_marker = 0;
1129 /* Uh-oh, the restart markers have been messed up. */
1130 /* Let the data source manager determine how to resync. */
1131 if (! (*cinfo->src->resync_to_restart) (cinfo,
1132 cinfo->marker->next_restart_num))
1136 /* Update next-restart state */
1137 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1144 * This is the default resync_to_restart method for data source managers
1145 * to use if they don't have any better approach. Some data source managers
1146 * may be able to back up, or may have additional knowledge about the data
1147 * which permits a more intelligent recovery strategy; such managers would
1148 * presumably supply their own resync method.
1150 * read_restart_marker calls resync_to_restart if it finds a marker other than
1151 * the restart marker it was expecting. (This code is *not* used unless
1152 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1153 * the marker code actually found (might be anything, except 0 or FF).
1154 * The desired restart marker number (0..7) is passed as a parameter.
1155 * This routine is supposed to apply whatever error recovery strategy seems
1156 * appropriate in order to position the input stream to the next data segment.
1157 * Note that cinfo->unread_marker is treated as a marker appearing before
1158 * the current data-source input point; usually it should be reset to zero
1160 * Returns FALSE if suspension is required.
1162 * This implementation is substantially constrained by wanting to treat the
1163 * input as a data stream; this means we can't back up. Therefore, we have
1164 * only the following actions to work with:
1165 * 1. Simply discard the marker and let the entropy decoder resume at next
1167 * 2. Read forward until we find another marker, discarding intervening
1168 * data. (In theory we could look ahead within the current bufferload,
1169 * without having to discard data if we don't find the desired marker.
1170 * This idea is not implemented here, in part because it makes behavior
1171 * dependent on buffer size and chance buffer-boundary positions.)
1172 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1173 * This will cause the entropy decoder to process an empty data segment,
1174 * inserting dummy zeroes, and then we will reprocess the marker.
1176 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1177 * appropriate if the found marker is a future restart marker (indicating
1178 * that we have missed the desired restart marker, probably because it got
1180 * We apply #2 or #3 if the found marker is a restart marker no more than
1181 * two counts behind or ahead of the expected one. We also apply #2 if the
1182 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1183 * If the found marker is a restart marker more than 2 counts away, we do #1
1184 * (too much risk that the marker is erroneous; with luck we will be able to
1185 * resync at some future point).
1186 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1187 * overrunning the end of a scan. An implementation limited to single-scan
1188 * files might find it better to apply #2 for markers other than EOI, since
1189 * any other marker would have to be bogus data in that case.
1193 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1195 int marker = cinfo->unread_marker;
1198 /* Always put up a warning. */
1199 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1201 /* Outer loop handles repeated decision after scanning forward. */
1203 if (marker < (int) M_SOF0)
1204 action = 2; /* invalid marker */
1205 else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1206 action = 3; /* valid non-restart marker */
1208 if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1209 marker == ((int) M_RST0 + ((desired+2) & 7)))
1210 action = 3; /* one of the next two expected restarts */
1211 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1212 marker == ((int) M_RST0 + ((desired-2) & 7)))
1213 action = 2; /* a prior restart, so advance */
1215 action = 1; /* desired restart or too far away */
1217 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1220 /* Discard marker and let entropy decoder resume processing. */
1221 cinfo->unread_marker = 0;
1224 /* Scan to the next marker, and repeat the decision loop. */
1225 if (! next_marker(cinfo))
1227 marker = cinfo->unread_marker;
1230 /* Return without advancing past this marker. */
1231 /* Entropy decoder will be forced to process an empty segment. */
1239 * Reset marker processing state to begin a fresh datastream.
1243 reset_marker_reader (j_decompress_ptr cinfo)
1245 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1247 cinfo->comp_info = NULL; /* until allocated by get_sof */
1248 cinfo->input_scan_number = 0; /* no SOS seen yet */
1249 cinfo->unread_marker = 0; /* no pending marker */
1250 marker->pub.saw_SOI = FALSE; /* set internal state too */
1251 marker->pub.saw_SOF = FALSE;
1252 marker->pub.discarded_bytes = 0;
1253 marker->cur_marker = NULL;
1258 * Initialize the marker reader module.
1259 * This is called only once, when the decompression object is created.
1263 jinit_marker_reader (j_decompress_ptr cinfo)
1265 my_marker_ptr marker;
1268 /* Create subobject in permanent pool */
1269 marker = (my_marker_ptr)
1270 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1271 SIZEOF(my_marker_reader));
1272 cinfo->marker = (struct jpeg_marker_reader *) marker;
1273 /* Initialize public method pointers */
1274 marker->pub.reset_marker_reader = reset_marker_reader;
1275 marker->pub.read_markers = read_markers;
1276 marker->pub.read_restart_marker = read_restart_marker;
1277 /* Initialize COM/APPn processing.
1278 * By default, we examine and then discard APP0 and APP14,
1279 * but simply discard COM and all other APPn.
1281 marker->process_COM = skip_variable;
1282 marker->length_limit_COM = 0;
1283 for (i = 0; i < 16; i++) {
1284 marker->process_APPn[i] = skip_variable;
1285 marker->length_limit_APPn[i] = 0;
1287 marker->process_APPn[0] = get_interesting_appn;
1288 marker->process_APPn[14] = get_interesting_appn;
1289 /* Reset marker processing state */
1290 reset_marker_reader(cinfo);
1295 * Control saving of COM and APPn markers into marker_list.
1298 #ifdef SAVE_MARKERS_SUPPORTED
1301 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1302 unsigned int length_limit)
1304 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1306 jpeg_marker_parser_method processor;
1308 /* Length limit mustn't be larger than what we can allocate
1309 * (should only be a concern in a 16-bit environment).
1311 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1312 if (((long) length_limit) > maxlength)
1313 length_limit = (unsigned int) maxlength;
1315 /* Choose processor routine to use.
1316 * APP0/APP14 have special requirements.
1319 processor = save_marker;
1320 /* If saving APP0/APP14, save at least enough for our internal use. */
1321 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1322 length_limit = APP0_DATA_LEN;
1323 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1324 length_limit = APP14_DATA_LEN;
1326 processor = skip_variable;
1327 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1328 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1329 processor = get_interesting_appn;
1332 if (marker_code == (int) M_COM) {
1333 marker->process_COM = processor;
1334 marker->length_limit_COM = length_limit;
1335 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1336 marker->process_APPn[marker_code - (int) M_APP0] = processor;
1337 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1339 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1342 #endif /* SAVE_MARKERS_SUPPORTED */
1346 * Install a special processing method for COM or APPn markers.
1350 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1351 jpeg_marker_parser_method routine)
1353 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1355 if (marker_code == (int) M_COM)
1356 marker->process_COM = routine;
1357 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1358 marker->process_APPn[marker_code - (int) M_APP0] = routine;
1360 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);