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
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
);
346 /* This CSi (cc) should differ from the previous CSi */
347 for (ci
= 0; ci
< i
; ci
++) {
348 if (cinfo
->cur_comp_info
[ci
] == compptr
)
349 ERREXIT1(cinfo
, JERR_BAD_COMPONENT_ID
, cc
);
353 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
354 INPUT_BYTE(cinfo
, c
, return FALSE
);
356 INPUT_BYTE(cinfo
, c
, return FALSE
);
358 INPUT_BYTE(cinfo
, c
, return FALSE
);
359 cinfo
->Ah
= (c
>> 4) & 15;
360 cinfo
->Al
= (c
) & 15;
362 TRACEMS4(cinfo
, 1, JTRC_SOS_PARAMS
, cinfo
->Ss
, cinfo
->Se
,
363 cinfo
->Ah
, cinfo
->Al
);
365 /* Prepare to scan data & restart markers */
366 cinfo
->marker
->next_restart_num
= 0;
368 /* Count another SOS marker */
369 cinfo
->input_scan_number
++;
376 #ifdef D_ARITH_CODING_SUPPORTED
379 get_dac (j_decompress_ptr cinfo
)
380 /* Process a DAC marker */
386 INPUT_2BYTES(cinfo
, length
, return FALSE
);
390 INPUT_BYTE(cinfo
, index
, return FALSE
);
391 INPUT_BYTE(cinfo
, val
, return FALSE
);
395 TRACEMS2(cinfo
, 1, JTRC_DAC
, index
, val
);
397 if (index
< 0 || index
>= (2*NUM_ARITH_TBLS
))
398 ERREXIT1(cinfo
, JERR_DAC_INDEX
, index
);
400 if (index
>= NUM_ARITH_TBLS
) { /* define AC table */
401 cinfo
->arith_ac_K
[index
-NUM_ARITH_TBLS
] = (UINT8
) val
;
402 } else { /* define DC table */
403 cinfo
->arith_dc_L
[index
] = (UINT8
) (val
& 0x0F);
404 cinfo
->arith_dc_U
[index
] = (UINT8
) (val
>> 4);
405 if (cinfo
->arith_dc_L
[index
] > cinfo
->arith_dc_U
[index
])
406 ERREXIT1(cinfo
, JERR_DAC_VALUE
, val
);
411 ERREXIT(cinfo
, JERR_BAD_LENGTH
);
417 #else /* ! D_ARITH_CODING_SUPPORTED */
419 #define get_dac(cinfo) skip_variable(cinfo)
421 #endif /* D_ARITH_CODING_SUPPORTED */
425 get_dht (j_decompress_ptr cinfo
)
426 /* Process a DHT marker */
435 INPUT_2BYTES(cinfo
, length
, return FALSE
);
438 while (length
> 16) {
439 INPUT_BYTE(cinfo
, index
, return FALSE
);
441 TRACEMS1(cinfo
, 1, JTRC_DHT
, index
);
445 for (i
= 1; i
<= 16; i
++) {
446 INPUT_BYTE(cinfo
, bits
[i
], return FALSE
);
452 TRACEMS8(cinfo
, 2, JTRC_HUFFBITS
,
453 bits
[1], bits
[2], bits
[3], bits
[4],
454 bits
[5], bits
[6], bits
[7], bits
[8]);
455 TRACEMS8(cinfo
, 2, JTRC_HUFFBITS
,
456 bits
[9], bits
[10], bits
[11], bits
[12],
457 bits
[13], bits
[14], bits
[15], bits
[16]);
459 /* Here we just do minimal validation of the counts to avoid walking
460 * off the end of our table space. jdhuff.c will check more carefully.
462 if (count
> 256 || ((INT32
) count
) > length
)
463 ERREXIT(cinfo
, JERR_BAD_HUFF_TABLE
);
465 for (i
= 0; i
< count
; i
++)
466 INPUT_BYTE(cinfo
, huffval
[i
], return FALSE
);
470 if (index
& 0x10) { /* AC table definition */
472 htblptr
= &cinfo
->ac_huff_tbl_ptrs
[index
];
473 } else { /* DC table definition */
474 htblptr
= &cinfo
->dc_huff_tbl_ptrs
[index
];
477 if (index
< 0 || index
>= NUM_HUFF_TBLS
)
478 ERREXIT1(cinfo
, JERR_DHT_INDEX
, index
);
480 if (*htblptr
== NULL
)
481 *htblptr
= jpeg_alloc_huff_table((j_common_ptr
) cinfo
);
483 MEMCOPY((*htblptr
)->bits
, bits
, SIZEOF((*htblptr
)->bits
));
484 MEMCOPY((*htblptr
)->huffval
, huffval
, SIZEOF((*htblptr
)->huffval
));
488 ERREXIT(cinfo
, JERR_BAD_LENGTH
);
496 get_dqt (j_decompress_ptr cinfo
)
497 /* Process a DQT marker */
502 JQUANT_TBL
*quant_ptr
;
505 INPUT_2BYTES(cinfo
, length
, return FALSE
);
509 INPUT_BYTE(cinfo
, n
, return FALSE
);
513 TRACEMS2(cinfo
, 1, JTRC_DQT
, n
, prec
);
515 if (n
>= NUM_QUANT_TBLS
)
516 ERREXIT1(cinfo
, JERR_DQT_INDEX
, n
);
518 if (cinfo
->quant_tbl_ptrs
[n
] == NULL
)
519 cinfo
->quant_tbl_ptrs
[n
] = jpeg_alloc_quant_table((j_common_ptr
) cinfo
);
520 quant_ptr
= cinfo
->quant_tbl_ptrs
[n
];
522 for (i
= 0; i
< DCTSIZE2
; i
++) {
524 INPUT_2BYTES(cinfo
, tmp
, return FALSE
);
526 INPUT_BYTE(cinfo
, tmp
, return FALSE
);
527 /* We convert the zigzag-order table to natural array order. */
528 quant_ptr
->quantval
[jpeg_natural_order
[i
]] = (UINT16
) tmp
;
531 if (cinfo
->err
->trace_level
>= 2) {
532 for (i
= 0; i
< DCTSIZE2
; i
+= 8) {
533 TRACEMS8(cinfo
, 2, JTRC_QUANTVALS
,
534 quant_ptr
->quantval
[i
], quant_ptr
->quantval
[i
+1],
535 quant_ptr
->quantval
[i
+2], quant_ptr
->quantval
[i
+3],
536 quant_ptr
->quantval
[i
+4], quant_ptr
->quantval
[i
+5],
537 quant_ptr
->quantval
[i
+6], quant_ptr
->quantval
[i
+7]);
541 length
-= DCTSIZE2
+1;
542 if (prec
) length
-= DCTSIZE2
;
546 ERREXIT(cinfo
, JERR_BAD_LENGTH
);
554 get_dri (j_decompress_ptr cinfo
)
555 /* Process a DRI marker */
561 INPUT_2BYTES(cinfo
, length
, return FALSE
);
564 ERREXIT(cinfo
, JERR_BAD_LENGTH
);
566 INPUT_2BYTES(cinfo
, tmp
, return FALSE
);
568 TRACEMS1(cinfo
, 1, JTRC_DRI
, tmp
);
570 cinfo
->restart_interval
= tmp
;
578 * Routines for processing APPn and COM markers.
579 * These are either saved in memory or discarded, per application request.
580 * APP0 and APP14 are specially checked to see if they are
581 * JFIF and Adobe markers, respectively.
584 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
585 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
586 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
590 examine_app0 (j_decompress_ptr cinfo
, JOCTET FAR
* data
,
591 unsigned int datalen
, INT32 remaining
)
592 /* Examine first few bytes from an APP0.
593 * Take appropriate action if it is a JFIF marker.
594 * datalen is # of bytes at data[], remaining is length of rest of marker data.
597 INT32 totallen
= (INT32
) datalen
+ remaining
;
599 if (datalen
>= APP0_DATA_LEN
&&
600 GETJOCTET(data
[0]) == 0x4A &&
601 GETJOCTET(data
[1]) == 0x46 &&
602 GETJOCTET(data
[2]) == 0x49 &&
603 GETJOCTET(data
[3]) == 0x46 &&
604 GETJOCTET(data
[4]) == 0) {
605 /* Found JFIF APP0 marker: save info */
606 cinfo
->saw_JFIF_marker
= TRUE
;
607 cinfo
->JFIF_major_version
= GETJOCTET(data
[5]);
608 cinfo
->JFIF_minor_version
= GETJOCTET(data
[6]);
609 cinfo
->density_unit
= GETJOCTET(data
[7]);
610 cinfo
->X_density
= (GETJOCTET(data
[8]) << 8) + GETJOCTET(data
[9]);
611 cinfo
->Y_density
= (GETJOCTET(data
[10]) << 8) + GETJOCTET(data
[11]);
613 * Major version must be 1, anything else signals an incompatible change.
614 * (We used to treat this as an error, but now it's a nonfatal warning,
615 * because some bozo at Hijaak couldn't read the spec.)
616 * Minor version should be 0..2, but process anyway if newer.
618 if (cinfo
->JFIF_major_version
!= 1)
619 WARNMS2(cinfo
, JWRN_JFIF_MAJOR
,
620 cinfo
->JFIF_major_version
, cinfo
->JFIF_minor_version
);
621 /* Generate trace messages */
622 TRACEMS5(cinfo
, 1, JTRC_JFIF
,
623 cinfo
->JFIF_major_version
, cinfo
->JFIF_minor_version
,
624 cinfo
->X_density
, cinfo
->Y_density
, cinfo
->density_unit
);
625 /* Validate thumbnail dimensions and issue appropriate messages */
626 if (GETJOCTET(data
[12]) | GETJOCTET(data
[13]))
627 TRACEMS2(cinfo
, 1, JTRC_JFIF_THUMBNAIL
,
628 GETJOCTET(data
[12]), GETJOCTET(data
[13]));
629 totallen
-= APP0_DATA_LEN
;
631 ((INT32
)GETJOCTET(data
[12]) * (INT32
)GETJOCTET(data
[13]) * (INT32
) 3))
632 TRACEMS1(cinfo
, 1, JTRC_JFIF_BADTHUMBNAILSIZE
, (int) totallen
);
633 } else if (datalen
>= 6 &&
634 GETJOCTET(data
[0]) == 0x4A &&
635 GETJOCTET(data
[1]) == 0x46 &&
636 GETJOCTET(data
[2]) == 0x58 &&
637 GETJOCTET(data
[3]) == 0x58 &&
638 GETJOCTET(data
[4]) == 0) {
639 /* Found JFIF "JFXX" extension APP0 marker */
640 /* The library doesn't actually do anything with these,
641 * but we try to produce a helpful trace message.
643 switch (GETJOCTET(data
[5])) {
645 TRACEMS1(cinfo
, 1, JTRC_THUMB_JPEG
, (int) totallen
);
648 TRACEMS1(cinfo
, 1, JTRC_THUMB_PALETTE
, (int) totallen
);
651 TRACEMS1(cinfo
, 1, JTRC_THUMB_RGB
, (int) totallen
);
654 TRACEMS2(cinfo
, 1, JTRC_JFIF_EXTENSION
,
655 GETJOCTET(data
[5]), (int) totallen
);
659 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
660 TRACEMS1(cinfo
, 1, JTRC_APP0
, (int) totallen
);
666 examine_app14 (j_decompress_ptr cinfo
, JOCTET FAR
* data
,
667 unsigned int datalen
, INT32 remaining
)
668 /* Examine first few bytes from an APP14.
669 * Take appropriate action if it is an Adobe marker.
670 * datalen is # of bytes at data[], remaining is length of rest of marker data.
673 unsigned int version
, flags0
, flags1
, transform
;
675 if (datalen
>= APP14_DATA_LEN
&&
676 GETJOCTET(data
[0]) == 0x41 &&
677 GETJOCTET(data
[1]) == 0x64 &&
678 GETJOCTET(data
[2]) == 0x6F &&
679 GETJOCTET(data
[3]) == 0x62 &&
680 GETJOCTET(data
[4]) == 0x65) {
681 /* Found Adobe APP14 marker */
682 version
= (GETJOCTET(data
[5]) << 8) + GETJOCTET(data
[6]);
683 flags0
= (GETJOCTET(data
[7]) << 8) + GETJOCTET(data
[8]);
684 flags1
= (GETJOCTET(data
[9]) << 8) + GETJOCTET(data
[10]);
685 transform
= GETJOCTET(data
[11]);
686 TRACEMS4(cinfo
, 1, JTRC_ADOBE
, version
, flags0
, flags1
, transform
);
687 cinfo
->saw_Adobe_marker
= TRUE
;
688 cinfo
->Adobe_transform
= (UINT8
) transform
;
690 /* Start of APP14 does not match "Adobe", or too short */
691 TRACEMS1(cinfo
, 1, JTRC_APP14
, (int) (datalen
+ remaining
));
697 get_interesting_appn (j_decompress_ptr cinfo
)
698 /* Process an APP0 or APP14 marker without saving it */
701 JOCTET b
[APPN_DATA_LEN
];
702 unsigned int i
, numtoread
;
705 INPUT_2BYTES(cinfo
, length
, return FALSE
);
708 /* get the interesting part of the marker data */
709 if (length
>= APPN_DATA_LEN
)
710 numtoread
= APPN_DATA_LEN
;
712 numtoread
= (unsigned int) length
;
715 for (i
= 0; i
< numtoread
; i
++)
716 INPUT_BYTE(cinfo
, b
[i
], return FALSE
);
720 switch (cinfo
->unread_marker
) {
722 examine_app0(cinfo
, (JOCTET FAR
*) b
, numtoread
, length
);
725 examine_app14(cinfo
, (JOCTET FAR
*) b
, numtoread
, length
);
728 /* can't get here unless jpeg_save_markers chooses wrong processor */
729 ERREXIT1(cinfo
, JERR_UNKNOWN_MARKER
, cinfo
->unread_marker
);
733 /* skip any remaining data -- could be lots */
736 (*cinfo
->src
->skip_input_data
) (cinfo
, (long) length
);
742 #ifdef SAVE_MARKERS_SUPPORTED
745 save_marker (j_decompress_ptr cinfo
)
746 /* Save an APPn or COM marker into the marker list */
748 my_marker_ptr marker
= (my_marker_ptr
) cinfo
->marker
;
749 jpeg_saved_marker_ptr cur_marker
= marker
->cur_marker
;
750 unsigned int bytes_read
, data_length
;
755 if (cur_marker
== NULL
) {
756 /* begin reading a marker */
757 INPUT_2BYTES(cinfo
, length
, return FALSE
);
759 if (length
>= 0) { /* watch out for bogus length word */
760 /* figure out how much we want to save */
762 if (cinfo
->unread_marker
== (int) M_COM
)
763 limit
= marker
->length_limit_COM
;
765 limit
= marker
->length_limit_APPn
[cinfo
->unread_marker
- (int) M_APP0
];
766 if ((unsigned int) length
< limit
)
767 limit
= (unsigned int) length
;
768 /* allocate and initialize the marker item */
769 cur_marker
= (jpeg_saved_marker_ptr
)
770 (*cinfo
->mem
->alloc_large
) ((j_common_ptr
) cinfo
, JPOOL_IMAGE
,
771 SIZEOF(struct jpeg_marker_struct
) + limit
);
772 cur_marker
->next
= NULL
;
773 cur_marker
->marker
= (UINT8
) cinfo
->unread_marker
;
774 cur_marker
->original_length
= (unsigned int) length
;
775 cur_marker
->data_length
= limit
;
776 /* data area is just beyond the jpeg_marker_struct */
777 data
= cur_marker
->data
= (JOCTET FAR
*) (cur_marker
+ 1);
778 marker
->cur_marker
= cur_marker
;
779 marker
->bytes_read
= 0;
783 /* deal with bogus length word */
784 bytes_read
= data_length
= 0;
788 /* resume reading a marker */
789 bytes_read
= marker
->bytes_read
;
790 data_length
= cur_marker
->data_length
;
791 data
= cur_marker
->data
+ bytes_read
;
794 while (bytes_read
< data_length
) {
795 INPUT_SYNC(cinfo
); /* move the restart point to here */
796 marker
->bytes_read
= bytes_read
;
797 /* If there's not at least one byte in buffer, suspend */
798 MAKE_BYTE_AVAIL(cinfo
, return FALSE
);
799 /* Copy bytes with reasonable rapidity */
800 while (bytes_read
< data_length
&& bytes_in_buffer
> 0) {
801 *data
++ = *next_input_byte
++;
807 /* Done reading what we want to read */
808 if (cur_marker
!= NULL
) { /* will be NULL if bogus length word */
809 /* Add new marker to end of list */
810 if (cinfo
->marker_list
== NULL
) {
811 cinfo
->marker_list
= cur_marker
;
813 jpeg_saved_marker_ptr prev
= cinfo
->marker_list
;
814 while (prev
->next
!= NULL
)
816 prev
->next
= cur_marker
;
818 /* Reset pointer & calc remaining data length */
819 data
= cur_marker
->data
;
820 length
= cur_marker
->original_length
- data_length
;
822 /* Reset to initial state for next marker */
823 marker
->cur_marker
= NULL
;
825 /* Process the marker if interesting; else just make a generic trace msg */
826 switch (cinfo
->unread_marker
) {
828 examine_app0(cinfo
, data
, data_length
, length
);
831 examine_app14(cinfo
, data
, data_length
, length
);
834 TRACEMS2(cinfo
, 1, JTRC_MISC_MARKER
, cinfo
->unread_marker
,
835 (int) (data_length
+ length
));
839 /* skip any remaining data -- could be lots */
840 INPUT_SYNC(cinfo
); /* do before skip_input_data */
842 (*cinfo
->src
->skip_input_data
) (cinfo
, (long) length
);
847 #endif /* SAVE_MARKERS_SUPPORTED */
851 skip_variable (j_decompress_ptr cinfo
)
852 /* Skip over an unknown or uninteresting variable-length marker */
857 INPUT_2BYTES(cinfo
, length
, return FALSE
);
860 TRACEMS2(cinfo
, 1, JTRC_MISC_MARKER
, cinfo
->unread_marker
, (int) length
);
862 INPUT_SYNC(cinfo
); /* do before skip_input_data */
864 (*cinfo
->src
->skip_input_data
) (cinfo
, (long) length
);
871 * Find the next JPEG marker, save it in cinfo->unread_marker.
872 * Returns FALSE if had to suspend before reaching a marker;
873 * in that case cinfo->unread_marker is unchanged.
875 * Note that the result might not be a valid marker code,
876 * but it will never be 0 or FF.
880 next_marker (j_decompress_ptr cinfo
)
886 INPUT_BYTE(cinfo
, c
, return FALSE
);
887 /* Skip any non-FF bytes.
888 * This may look a bit inefficient, but it will not occur in a valid file.
889 * We sync after each discarded byte so that a suspending data source
890 * can discard the byte from its buffer.
893 cinfo
->marker
->discarded_bytes
++;
895 INPUT_BYTE(cinfo
, c
, return FALSE
);
897 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
898 * pad bytes, so don't count them in discarded_bytes. We assume there
899 * will not be so many consecutive FF bytes as to overflow a suspending
900 * data source's input buffer.
903 INPUT_BYTE(cinfo
, c
, return FALSE
);
906 break; /* found a valid marker, exit loop */
907 /* Reach here if we found a stuffed-zero data sequence (FF/00).
908 * Discard it and loop back to try again.
910 cinfo
->marker
->discarded_bytes
+= 2;
914 if (cinfo
->marker
->discarded_bytes
!= 0) {
915 WARNMS2(cinfo
, JWRN_EXTRANEOUS_DATA
, cinfo
->marker
->discarded_bytes
, c
);
916 cinfo
->marker
->discarded_bytes
= 0;
919 cinfo
->unread_marker
= c
;
927 first_marker (j_decompress_ptr cinfo
)
928 /* Like next_marker, but used to obtain the initial SOI marker. */
929 /* For this marker, we do not allow preceding garbage or fill; otherwise,
930 * we might well scan an entire input file before realizing it ain't JPEG.
931 * If an application wants to process non-JFIF files, it must seek to the
932 * SOI before calling the JPEG library.
938 INPUT_BYTE(cinfo
, c
, return FALSE
);
939 INPUT_BYTE(cinfo
, c2
, return FALSE
);
940 if (c
!= 0xFF || c2
!= (int) M_SOI
)
941 ERREXIT2(cinfo
, JERR_NO_SOI
, c
, c2
);
943 cinfo
->unread_marker
= c2
;
951 * Read markers until SOS or EOI.
953 * Returns same codes as are defined for jpeg_consume_input:
954 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
958 read_markers (j_decompress_ptr cinfo
)
960 /* Outer loop repeats once for each marker. */
962 /* Collect the marker proper, unless we already did. */
963 /* NB: first_marker() enforces the requirement that SOI appear first. */
964 if (cinfo
->unread_marker
== 0) {
965 if (! cinfo
->marker
->saw_SOI
) {
966 if (! first_marker(cinfo
))
967 return JPEG_SUSPENDED
;
969 if (! next_marker(cinfo
))
970 return JPEG_SUSPENDED
;
973 /* At this point cinfo->unread_marker contains the marker code and the
974 * input point is just past the marker proper, but before any parameters.
975 * A suspension will cause us to return with this state still true.
977 switch (cinfo
->unread_marker
) {
979 if (! get_soi(cinfo
))
980 return JPEG_SUSPENDED
;
983 case M_SOF0
: /* Baseline */
984 case M_SOF1
: /* Extended sequential, Huffman */
985 if (! get_sof(cinfo
, FALSE
, FALSE
))
986 return JPEG_SUSPENDED
;
989 case M_SOF2
: /* Progressive, Huffman */
990 if (! get_sof(cinfo
, TRUE
, FALSE
))
991 return JPEG_SUSPENDED
;
994 case M_SOF9
: /* Extended sequential, arithmetic */
995 if (! get_sof(cinfo
, FALSE
, TRUE
))
996 return JPEG_SUSPENDED
;
999 case M_SOF10
: /* Progressive, arithmetic */
1000 if (! get_sof(cinfo
, TRUE
, TRUE
))
1001 return JPEG_SUSPENDED
;
1004 /* Currently unsupported SOFn types */
1005 case M_SOF3
: /* Lossless, Huffman */
1006 case M_SOF5
: /* Differential sequential, Huffman */
1007 case M_SOF6
: /* Differential progressive, Huffman */
1008 case M_SOF7
: /* Differential lossless, Huffman */
1009 case M_JPG
: /* Reserved for JPEG extensions */
1010 case M_SOF11
: /* Lossless, arithmetic */
1011 case M_SOF13
: /* Differential sequential, arithmetic */
1012 case M_SOF14
: /* Differential progressive, arithmetic */
1013 case M_SOF15
: /* Differential lossless, arithmetic */
1014 ERREXIT1(cinfo
, JERR_SOF_UNSUPPORTED
, cinfo
->unread_marker
);
1018 if (! get_sos(cinfo
))
1019 return JPEG_SUSPENDED
;
1020 cinfo
->unread_marker
= 0; /* processed the marker */
1021 return JPEG_REACHED_SOS
;
1024 TRACEMS(cinfo
, 1, JTRC_EOI
);
1025 cinfo
->unread_marker
= 0; /* processed the marker */
1026 return JPEG_REACHED_EOI
;
1029 if (! get_dac(cinfo
))
1030 return JPEG_SUSPENDED
;
1034 if (! get_dht(cinfo
))
1035 return JPEG_SUSPENDED
;
1039 if (! get_dqt(cinfo
))
1040 return JPEG_SUSPENDED
;
1044 if (! get_dri(cinfo
))
1045 return JPEG_SUSPENDED
;
1064 if (! (*((my_marker_ptr
) cinfo
->marker
)->process_APPn
[
1065 cinfo
->unread_marker
- (int) M_APP0
]) (cinfo
))
1066 return JPEG_SUSPENDED
;
1070 if (! (*((my_marker_ptr
) cinfo
->marker
)->process_COM
) (cinfo
))
1071 return JPEG_SUSPENDED
;
1074 case M_RST0
: /* these are all parameterless */
1083 TRACEMS1(cinfo
, 1, JTRC_PARMLESS_MARKER
, cinfo
->unread_marker
);
1086 case M_DNL
: /* Ignore DNL ... perhaps the wrong thing */
1087 if (! skip_variable(cinfo
))
1088 return JPEG_SUSPENDED
;
1091 default: /* must be DHP, EXP, JPGn, or RESn */
1092 /* For now, we treat the reserved markers as fatal errors since they are
1093 * likely to be used to signal incompatible JPEG Part 3 extensions.
1094 * Once the JPEG 3 version-number marker is well defined, this code
1097 ERREXIT1(cinfo
, JERR_UNKNOWN_MARKER
, cinfo
->unread_marker
);
1100 /* Successfully processed marker, so reset state variable */
1101 cinfo
->unread_marker
= 0;
1107 * Read a restart marker, which is expected to appear next in the datastream;
1108 * if the marker is not there, take appropriate recovery action.
1109 * Returns FALSE if suspension is required.
1111 * This is called by the entropy decoder after it has read an appropriate
1112 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1113 * has already read a marker from the data source. Under normal conditions
1114 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1115 * it holds a marker which the decoder will be unable to read past.
1119 read_restart_marker (j_decompress_ptr cinfo
)
1121 /* Obtain a marker unless we already did. */
1122 /* Note that next_marker will complain if it skips any data. */
1123 if (cinfo
->unread_marker
== 0) {
1124 if (! next_marker(cinfo
))
1128 if (cinfo
->unread_marker
==
1129 ((int) M_RST0
+ cinfo
->marker
->next_restart_num
)) {
1130 /* Normal case --- swallow the marker and let entropy decoder continue */
1131 TRACEMS1(cinfo
, 3, JTRC_RST
, cinfo
->marker
->next_restart_num
);
1132 cinfo
->unread_marker
= 0;
1134 /* Uh-oh, the restart markers have been messed up. */
1135 /* Let the data source manager determine how to resync. */
1136 if (! (*cinfo
->src
->resync_to_restart
) (cinfo
,
1137 cinfo
->marker
->next_restart_num
))
1141 /* Update next-restart state */
1142 cinfo
->marker
->next_restart_num
= (cinfo
->marker
->next_restart_num
+ 1) & 7;
1149 * This is the default resync_to_restart method for data source managers
1150 * to use if they don't have any better approach. Some data source managers
1151 * may be able to back up, or may have additional knowledge about the data
1152 * which permits a more intelligent recovery strategy; such managers would
1153 * presumably supply their own resync method.
1155 * read_restart_marker calls resync_to_restart if it finds a marker other than
1156 * the restart marker it was expecting. (This code is *not* used unless
1157 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1158 * the marker code actually found (might be anything, except 0 or FF).
1159 * The desired restart marker number (0..7) is passed as a parameter.
1160 * This routine is supposed to apply whatever error recovery strategy seems
1161 * appropriate in order to position the input stream to the next data segment.
1162 * Note that cinfo->unread_marker is treated as a marker appearing before
1163 * the current data-source input point; usually it should be reset to zero
1165 * Returns FALSE if suspension is required.
1167 * This implementation is substantially constrained by wanting to treat the
1168 * input as a data stream; this means we can't back up. Therefore, we have
1169 * only the following actions to work with:
1170 * 1. Simply discard the marker and let the entropy decoder resume at next
1172 * 2. Read forward until we find another marker, discarding intervening
1173 * data. (In theory we could look ahead within the current bufferload,
1174 * without having to discard data if we don't find the desired marker.
1175 * This idea is not implemented here, in part because it makes behavior
1176 * dependent on buffer size and chance buffer-boundary positions.)
1177 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1178 * This will cause the entropy decoder to process an empty data segment,
1179 * inserting dummy zeroes, and then we will reprocess the marker.
1181 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1182 * appropriate if the found marker is a future restart marker (indicating
1183 * that we have missed the desired restart marker, probably because it got
1185 * We apply #2 or #3 if the found marker is a restart marker no more than
1186 * two counts behind or ahead of the expected one. We also apply #2 if the
1187 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1188 * If the found marker is a restart marker more than 2 counts away, we do #1
1189 * (too much risk that the marker is erroneous; with luck we will be able to
1190 * resync at some future point).
1191 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1192 * overrunning the end of a scan. An implementation limited to single-scan
1193 * files might find it better to apply #2 for markers other than EOI, since
1194 * any other marker would have to be bogus data in that case.
1198 jpeg_resync_to_restart (j_decompress_ptr cinfo
, int desired
)
1200 int marker
= cinfo
->unread_marker
;
1203 /* Always put up a warning. */
1204 WARNMS2(cinfo
, JWRN_MUST_RESYNC
, marker
, desired
);
1206 /* Outer loop handles repeated decision after scanning forward. */
1208 if (marker
< (int) M_SOF0
)
1209 action
= 2; /* invalid marker */
1210 else if (marker
< (int) M_RST0
|| marker
> (int) M_RST7
)
1211 action
= 3; /* valid non-restart marker */
1213 if (marker
== ((int) M_RST0
+ ((desired
+1) & 7)) ||
1214 marker
== ((int) M_RST0
+ ((desired
+2) & 7)))
1215 action
= 3; /* one of the next two expected restarts */
1216 else if (marker
== ((int) M_RST0
+ ((desired
-1) & 7)) ||
1217 marker
== ((int) M_RST0
+ ((desired
-2) & 7)))
1218 action
= 2; /* a prior restart, so advance */
1220 action
= 1; /* desired restart or too far away */
1222 TRACEMS2(cinfo
, 4, JTRC_RECOVERY_ACTION
, marker
, action
);
1225 /* Discard marker and let entropy decoder resume processing. */
1226 cinfo
->unread_marker
= 0;
1229 /* Scan to the next marker, and repeat the decision loop. */
1230 if (! next_marker(cinfo
))
1232 marker
= cinfo
->unread_marker
;
1235 /* Return without advancing past this marker. */
1236 /* Entropy decoder will be forced to process an empty segment. */
1244 * Reset marker processing state to begin a fresh datastream.
1248 reset_marker_reader (j_decompress_ptr cinfo
)
1250 my_marker_ptr marker
= (my_marker_ptr
) cinfo
->marker
;
1252 cinfo
->comp_info
= NULL
; /* until allocated by get_sof */
1253 cinfo
->input_scan_number
= 0; /* no SOS seen yet */
1254 cinfo
->unread_marker
= 0; /* no pending marker */
1255 marker
->pub
.saw_SOI
= FALSE
; /* set internal state too */
1256 marker
->pub
.saw_SOF
= FALSE
;
1257 marker
->pub
.discarded_bytes
= 0;
1258 marker
->cur_marker
= NULL
;
1263 * Initialize the marker reader module.
1264 * This is called only once, when the decompression object is created.
1268 jinit_marker_reader (j_decompress_ptr cinfo
)
1270 my_marker_ptr marker
;
1273 /* Create subobject in permanent pool */
1274 marker
= (my_marker_ptr
)
1275 (*cinfo
->mem
->alloc_small
) ((j_common_ptr
) cinfo
, JPOOL_PERMANENT
,
1276 SIZEOF(my_marker_reader
));
1277 cinfo
->marker
= (struct jpeg_marker_reader
*) marker
;
1278 /* Initialize public method pointers */
1279 marker
->pub
.reset_marker_reader
= reset_marker_reader
;
1280 marker
->pub
.read_markers
= read_markers
;
1281 marker
->pub
.read_restart_marker
= read_restart_marker
;
1282 /* Initialize COM/APPn processing.
1283 * By default, we examine and then discard APP0 and APP14,
1284 * but simply discard COM and all other APPn.
1286 marker
->process_COM
= skip_variable
;
1287 marker
->length_limit_COM
= 0;
1288 for (i
= 0; i
< 16; i
++) {
1289 marker
->process_APPn
[i
] = skip_variable
;
1290 marker
->length_limit_APPn
[i
] = 0;
1292 marker
->process_APPn
[0] = get_interesting_appn
;
1293 marker
->process_APPn
[14] = get_interesting_appn
;
1294 /* Reset marker processing state */
1295 reset_marker_reader(cinfo
);
1300 * Control saving of COM and APPn markers into marker_list.
1303 #ifdef SAVE_MARKERS_SUPPORTED
1306 jpeg_save_markers (j_decompress_ptr cinfo
, int marker_code
,
1307 unsigned int length_limit
)
1309 my_marker_ptr marker
= (my_marker_ptr
) cinfo
->marker
;
1311 jpeg_marker_parser_method processor
;
1313 /* Length limit mustn't be larger than what we can allocate
1314 * (should only be a concern in a 16-bit environment).
1316 maxlength
= cinfo
->mem
->max_alloc_chunk
- SIZEOF(struct jpeg_marker_struct
);
1317 if (((long) length_limit
) > maxlength
)
1318 length_limit
= (unsigned int) maxlength
;
1320 /* Choose processor routine to use.
1321 * APP0/APP14 have special requirements.
1324 processor
= save_marker
;
1325 /* If saving APP0/APP14, save at least enough for our internal use. */
1326 if (marker_code
== (int) M_APP0
&& length_limit
< APP0_DATA_LEN
)
1327 length_limit
= APP0_DATA_LEN
;
1328 else if (marker_code
== (int) M_APP14
&& length_limit
< APP14_DATA_LEN
)
1329 length_limit
= APP14_DATA_LEN
;
1331 processor
= skip_variable
;
1332 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1333 if (marker_code
== (int) M_APP0
|| marker_code
== (int) M_APP14
)
1334 processor
= get_interesting_appn
;
1337 if (marker_code
== (int) M_COM
) {
1338 marker
->process_COM
= processor
;
1339 marker
->length_limit_COM
= length_limit
;
1340 } else if (marker_code
>= (int) M_APP0
&& marker_code
<= (int) M_APP15
) {
1341 marker
->process_APPn
[marker_code
- (int) M_APP0
] = processor
;
1342 marker
->length_limit_APPn
[marker_code
- (int) M_APP0
] = length_limit
;
1344 ERREXIT1(cinfo
, JERR_UNKNOWN_MARKER
, marker_code
);
1347 #endif /* SAVE_MARKERS_SUPPORTED */
1351 * Install a special processing method for COM or APPn markers.
1355 jpeg_set_marker_processor (j_decompress_ptr cinfo
, int marker_code
,
1356 jpeg_marker_parser_method routine
)
1358 my_marker_ptr marker
= (my_marker_ptr
) cinfo
->marker
;
1360 if (marker_code
== (int) M_COM
)
1361 marker
->process_COM
= routine
;
1362 else if (marker_code
>= (int) M_APP0
&& marker_code
<= (int) M_APP15
)
1363 marker
->process_APPn
[marker_code
- (int) M_APP0
] = routine
;
1365 ERREXIT1(cinfo
, JERR_UNKNOWN_MARKER
, marker_code
);