ref: 1ccd0cd04d75840861e26f6c5f6ac73396d43d8a
dir: /sys/src/cmd/gs/jpeg/jdmarker.c/
/*
* jdmarker.c
*
* Copyright (C) 1991-1998, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains routines to decode JPEG datastream markers.
* Most of the complexity arises from our desire to support input
* suspension: if not all of the data for a marker is available,
* we must exit back to the application. On resumption, we reprocess
* the marker.
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
typedef enum { /* JPEG marker codes */
M_SOF0 = 0xc0,
M_SOF1 = 0xc1,
M_SOF2 = 0xc2,
M_SOF3 = 0xc3,
M_SOF5 = 0xc5,
M_SOF6 = 0xc6,
M_SOF7 = 0xc7,
M_JPG = 0xc8,
M_SOF9 = 0xc9,
M_SOF10 = 0xca,
M_SOF11 = 0xcb,
M_SOF13 = 0xcd,
M_SOF14 = 0xce,
M_SOF15 = 0xcf,
M_DHT = 0xc4,
M_DAC = 0xcc,
M_RST0 = 0xd0,
M_RST1 = 0xd1,
M_RST2 = 0xd2,
M_RST3 = 0xd3,
M_RST4 = 0xd4,
M_RST5 = 0xd5,
M_RST6 = 0xd6,
M_RST7 = 0xd7,
M_SOI = 0xd8,
M_EOI = 0xd9,
M_SOS = 0xda,
M_DQT = 0xdb,
M_DNL = 0xdc,
M_DRI = 0xdd,
M_DHP = 0xde,
M_EXP = 0xdf,
M_APP0 = 0xe0,
M_APP1 = 0xe1,
M_APP2 = 0xe2,
M_APP3 = 0xe3,
M_APP4 = 0xe4,
M_APP5 = 0xe5,
M_APP6 = 0xe6,
M_APP7 = 0xe7,
M_APP8 = 0xe8,
M_APP9 = 0xe9,
M_APP10 = 0xea,
M_APP11 = 0xeb,
M_APP12 = 0xec,
M_APP13 = 0xed,
M_APP14 = 0xee,
M_APP15 = 0xef,
M_JPG0 = 0xf0,
M_JPG13 = 0xfd,
M_COM = 0xfe,
M_TEM = 0x01,
M_ERROR = 0x100
} JPEG_MARKER;
/* Private state */
typedef struct {
struct jpeg_marker_reader pub; /* public fields */
/* Application-overridable marker processing methods */
jpeg_marker_parser_method process_COM;
jpeg_marker_parser_method process_APPn[16];
/* Limit on marker data length to save for each marker type */
unsigned int length_limit_COM;
unsigned int length_limit_APPn[16];
/* Status of COM/APPn marker saving */
jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
unsigned int bytes_read; /* data bytes read so far in marker */
/* Note: cur_marker is not linked into marker_list until it's all read. */
} my_marker_reader;
typedef my_marker_reader * my_marker_ptr;
/*
* Macros for fetching data from the data source module.
*
* At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
* the current restart point; we update them only when we have reached a
* suitable place to restart if a suspension occurs.
*/
/* Declare and initialize local copies of input pointer/count */
#define INPUT_VARS(cinfo) \
struct jpeg_source_mgr * datasrc = (cinfo)->src; \
const JOCTET * next_input_byte = datasrc->next_input_byte; \
size_t bytes_in_buffer = datasrc->bytes_in_buffer
/* Unload the local copies --- do this only at a restart boundary */
#define INPUT_SYNC(cinfo) \
( datasrc->next_input_byte = next_input_byte, \
datasrc->bytes_in_buffer = bytes_in_buffer )
/* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
#define INPUT_RELOAD(cinfo) \
( next_input_byte = datasrc->next_input_byte, \
bytes_in_buffer = datasrc->bytes_in_buffer )
/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
* Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
* but we must reload the local copies after a successful fill.
*/
#define MAKE_BYTE_AVAIL(cinfo,action) \
if (bytes_in_buffer == 0) { \
if (! (*datasrc->fill_input_buffer) (cinfo)) \
{ action; } \
INPUT_RELOAD(cinfo); \
}
/* Read a byte into variable V.
* If must suspend, take the specified action (typically "return FALSE").
*/
#define INPUT_BYTE(cinfo,V,action) \
MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
bytes_in_buffer--; \
V = GETJOCTET(*next_input_byte++); )
/* As above, but read two bytes interpreted as an unsigned 16-bit integer.
* V should be declared unsigned int or perhaps INT32.
*/
#define INPUT_2BYTES(cinfo,V,action) \
MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
bytes_in_buffer--; \
V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
MAKE_BYTE_AVAIL(cinfo,action); \
bytes_in_buffer--; \
V += GETJOCTET(*next_input_byte++); )
/*
* Routines to process JPEG markers.
*
* Entry condition: JPEG marker itself has been read and its code saved
* in cinfo->unread_marker; input restart point is just after the marker.
*
* Exit: if return TRUE, have read and processed any parameters, and have
* updated the restart point to point after the parameters.
* If return FALSE, was forced to suspend before reaching end of
* marker parameters; restart point has not been moved. Same routine
* will be called again after application supplies more input data.
*
* This approach to suspension assumes that all of a marker's parameters
* can fit into a single input bufferload. This should hold for "normal"
* markers. Some COM/APPn markers might have large parameter segments
* that might not fit. If we are simply dropping such a marker, we use
* skip_input_data to get past it, and thereby put the problem on the
* source manager's shoulders. If we are saving the marker's contents
* into memory, we use a slightly different convention: when forced to
* suspend, the marker processor updates the restart point to the end of
* what it's consumed (ie, the end of the buffer) before returning FALSE.
* On resumption, cinfo->unread_marker still contains the marker code,
* but the data source will point to the next chunk of marker data.
* The marker processor must retain internal state to deal with this.
*
* Note that we don't bother to avoid duplicate trace messages if a
* suspension occurs within marker parameters. Other side effects
* require more care.
*/
LOCAL(boolean)
get_soi (j_decompress_ptr cinfo)
/* Process an SOI marker */
{
int i;
TRACEMS(cinfo, 1, JTRC_SOI);
if (cinfo->marker->saw_SOI)
ERREXIT(cinfo, JERR_SOI_DUPLICATE);
/* Reset all parameters that are defined to be reset by SOI */
for (i = 0; i < NUM_ARITH_TBLS; i++) {
cinfo->arith_dc_L[i] = 0;
cinfo->arith_dc_U[i] = 1;
cinfo->arith_ac_K[i] = 5;
}
cinfo->restart_interval = 0;
/* Set initial assumptions for colorspace etc */
cinfo->jpeg_color_space = JCS_UNKNOWN;
cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
cinfo->saw_JFIF_marker = FALSE;
cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
cinfo->JFIF_minor_version = 1;
cinfo->density_unit = 0;
cinfo->X_density = 1;
cinfo->Y_density = 1;
cinfo->saw_Adobe_marker = FALSE;
cinfo->Adobe_transform = 0;
cinfo->marker->saw_SOI = TRUE;
return TRUE;
}
LOCAL(boolean)
get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
/* Process a SOFn marker */
{
INT32 length;
int c, ci;
jpeg_component_info * compptr;
INPUT_VARS(cinfo);
cinfo->progressive_mode = is_prog;
cinfo->arith_code = is_arith;
INPUT_2BYTES(cinfo, length, return FALSE);
INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
length -= 8;
TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
(int) cinfo->image_width, (int) cinfo->image_height,
cinfo->num_components);
if (cinfo->marker->saw_SOF)
ERREXIT(cinfo, JERR_SOF_DUPLICATE);
/* We don't support files in which the image height is initially specified */
/* as 0 and is later redefined by DNL. As long as we have to check that, */
/* might as well have a general sanity check. */
if (cinfo->image_height <= 0 || cinfo->image_width <= 0
|| cinfo->num_components <= 0)
ERREXIT(cinfo, JERR_EMPTY_IMAGE);
if (length != (cinfo->num_components * 3))
ERREXIT(cinfo, JERR_BAD_LENGTH);
if (cinfo->comp_info == NULL) /* do only once, even if suspend */
cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
((j_common_ptr) cinfo, JPOOL_IMAGE,
cinfo->num_components * SIZEOF(jpeg_component_info));
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
compptr->component_index = ci;
INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
INPUT_BYTE(cinfo, c, return FALSE);
compptr->h_samp_factor = (c >> 4) & 15;
compptr->v_samp_factor = (c ) & 15;
INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
compptr->component_id, compptr->h_samp_factor,
compptr->v_samp_factor, compptr->quant_tbl_no);
}
cinfo->marker->saw_SOF = TRUE;
INPUT_SYNC(cinfo);
return TRUE;
}
LOCAL(boolean)
get_sos (j_decompress_ptr cinfo)
/* Process a SOS marker */
{
INT32 length;
int i, ci, n, c, cc;
jpeg_component_info * compptr;
INPUT_VARS(cinfo);
if (! cinfo->marker->saw_SOF)
ERREXIT(cinfo, JERR_SOS_NO_SOF);
INPUT_2BYTES(cinfo, length, return FALSE);
INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
TRACEMS1(cinfo, 1, JTRC_SOS, n);
if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
ERREXIT(cinfo, JERR_BAD_LENGTH);
cinfo->comps_in_scan = n;
/* Collect the component-spec parameters */
for (i = 0; i < n; i++) {
INPUT_BYTE(cinfo, cc, return FALSE);
INPUT_BYTE(cinfo, c, return FALSE);
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
if (cc == compptr->component_id)
goto id_found;
}
ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
id_found:
cinfo->cur_comp_info[i] = compptr;
compptr->dc_tbl_no = (c >> 4) & 15;
compptr->ac_tbl_no = (c ) & 15;
TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
compptr->dc_tbl_no, compptr->ac_tbl_no);
}
/* Collect the additional scan parameters Ss, Se, Ah/Al. */
INPUT_BYTE(cinfo, c, return FALSE);
cinfo->Ss = c;
INPUT_BYTE(cinfo, c, return FALSE);
cinfo->Se = c;
INPUT_BYTE(cinfo, c, return FALSE);
cinfo->Ah = (c >> 4) & 15;
cinfo->Al = (c ) & 15;
TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
cinfo->Ah, cinfo->Al);
/* Prepare to scan data & restart markers */
cinfo->marker->next_restart_num = 0;
/* Count another SOS marker */
cinfo->input_scan_number++;
INPUT_SYNC(cinfo);
return TRUE;
}
#ifdef D_ARITH_CODING_SUPPORTED
LOCAL(boolean)
get_dac (j_decompress_ptr cinfo)
/* Process a DAC marker */
{
INT32 length;
int index, val;
INPUT_VARS(cinfo);
INPUT_2BYTES(cinfo, length, return FALSE);
length -= 2;
while (length > 0) {
INPUT_BYTE(cinfo, index, return FALSE);
INPUT_BYTE(cinfo, val, return FALSE);
length -= 2;
TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
if (index < 0 || index >= (2*NUM_ARITH_TBLS))
ERREXIT1(cinfo, JERR_DAC_INDEX, index);
if (index >= NUM_ARITH_TBLS) { /* define AC table */
cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
} else { /* define DC table */
cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
ERREXIT1(cinfo, JERR_DAC_VALUE, val);
}
}
if (length != 0)
ERREXIT(cinfo, JERR_BAD_LENGTH);
INPUT_SYNC(cinfo);
return TRUE;
}
#else /* ! D_ARITH_CODING_SUPPORTED */
#define get_dac(cinfo) skip_variable(cinfo)
#endif /* D_ARITH_CODING_SUPPORTED */
LOCAL(boolean)
get_dht (j_decompress_ptr cinfo)
/* Process a DHT marker */
{
INT32 length;
UINT8 bits[17];
UINT8 huffval[256];
int i, index, count;
JHUFF_TBL **htblptr;
INPUT_VARS(cinfo);
INPUT_2BYTES(cinfo, length, return FALSE);
length -= 2;
while (length > 16) {
INPUT_BYTE(cinfo, index, return FALSE);
TRACEMS1(cinfo, 1, JTRC_DHT, index);
bits[0] = 0;
count = 0;
for (i = 1; i <= 16; i++) {
INPUT_BYTE(cinfo, bits[i], return FALSE);
count += bits[i];
}
length -= 1 + 16;
TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
bits[1], bits[2], bits[3], bits[4],
bits[5], bits[6], bits[7], bits[8]);
TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
bits[9], bits[10], bits[11], bits[12],
bits[13], bits[14], bits[15], bits[16]);
/* Here we just do minimal validation of the counts to avoid walking
* off the end of our table space. jdhuff.c will check more carefully.
*/
if (count > 256 || ((INT32) count) > length)
ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
for (i = 0; i < count; i++)
INPUT_BYTE(cinfo, huffval[i], return FALSE);
length -= count;
if (index & 0x10) { /* AC table definition */
index -= 0x10;
htblptr = &cinfo->ac_huff_tbl_ptrs[index];
} else { /* DC table definition */
htblptr = &cinfo->dc_huff_tbl_ptrs[index];
}
if (index < 0 || index >= NUM_HUFF_TBLS)
ERREXIT1(cinfo, JERR_DHT_INDEX, index);
if (*htblptr == NULL)
*htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
}
if (length != 0)
ERREXIT(cinfo, JERR_BAD_LENGTH);
INPUT_SYNC(cinfo);
return TRUE;
}
LOCAL(boolean)
get_dqt (j_decompress_ptr cinfo)
/* Process a DQT marker */
{
INT32 length;
int n, i, prec;
unsigned int tmp;
JQUANT_TBL *quant_ptr;
INPUT_VARS(cinfo);
INPUT_2BYTES(cinfo, length, return FALSE);
length -= 2;
while (length > 0) {
INPUT_BYTE(cinfo, n, return FALSE);
prec = n >> 4;
n &= 0x0F;
TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
if (n >= NUM_QUANT_TBLS)
ERREXIT1(cinfo, JERR_DQT_INDEX, n);
if (cinfo->quant_tbl_ptrs[n] == NULL)
cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
quant_ptr = cinfo->quant_tbl_ptrs[n];
for (i = 0; i < DCTSIZE2; i++) {
if (prec)
INPUT_2BYTES(cinfo, tmp, return FALSE);
else
INPUT_BYTE(cinfo, tmp, return FALSE);
/* We convert the zigzag-order table to natural array order. */
quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
}
if (cinfo->err->trace_level >= 2) {
for (i = 0; i < DCTSIZE2; i += 8) {
TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
quant_ptr->quantval[i], quant_ptr->quantval[i+1],
quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
}
}
length -= DCTSIZE2+1;
if (prec) length -= DCTSIZE2;
}
if (length != 0)
ERREXIT(cinfo, JERR_BAD_LENGTH);
INPUT_SYNC(cinfo);
return TRUE;
}
LOCAL(boolean)
get_dri (j_decompress_ptr cinfo)
/* Process a DRI marker */
{
INT32 length;
unsigned int tmp;
INPUT_VARS(cinfo);
INPUT_2BYTES(cinfo, length, return FALSE);
if (length != 4)
ERREXIT(cinfo, JERR_BAD_LENGTH);
INPUT_2BYTES(cinfo, tmp, return FALSE);
TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
cinfo->restart_interval = tmp;
INPUT_SYNC(cinfo);
return TRUE;
}
/*
* Routines for processing APPn and COM markers.
* These are either saved in memory or discarded, per application request.
* APP0 and APP14 are specially checked to see if they are
* JFIF and Adobe markers, respectively.
*/
#define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
#define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
#define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
LOCAL(void)
examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
unsigned int datalen, INT32 remaining)
/* Examine first few bytes from an APP0.
* Take appropriate action if it is a JFIF marker.
* datalen is # of bytes at data[], remaining is length of rest of marker data.
*/
{
INT32 totallen = (INT32) datalen + remaining;
if (datalen >= APP0_DATA_LEN &&
GETJOCTET(data[0]) == 0x4A &&
GETJOCTET(data[1]) == 0x46 &&
GETJOCTET(data[2]) == 0x49 &&
GETJOCTET(data[3]) == 0x46 &&
GETJOCTET(data[4]) == 0) {
/* Found JFIF APP0 marker: save info */
cinfo->saw_JFIF_marker = TRUE;
cinfo->JFIF_major_version = GETJOCTET(data[5]);
cinfo->JFIF_minor_version = GETJOCTET(data[6]);
cinfo->density_unit = GETJOCTET(data[7]);
cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
/* Check version.
* Major version must be 1, anything else signals an incompatible change.
* (We used to treat this as an error, but now it's a nonfatal warning,
* because some bozo at Hijaak couldn't read the spec.)
* Minor version should be 0..2, but process anyway if newer.
*/
if (cinfo->JFIF_major_version != 1)
WARNMS2(cinfo, JWRN_JFIF_MAJOR,
cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
/* Generate trace messages */
TRACEMS5(cinfo, 1, JTRC_JFIF,
cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
/* Validate thumbnail dimensions and issue appropriate messages */
if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
GETJOCTET(data[12]), GETJOCTET(data[13]));
totallen -= APP0_DATA_LEN;
if (totallen !=
((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
} else if (datalen >= 6 &&
GETJOCTET(data[0]) == 0x4A &&
GETJOCTET(data[1]) == 0x46 &&
GETJOCTET(data[2]) == 0x58 &&
GETJOCTET(data[3]) == 0x58 &&
GETJOCTET(data[4]) == 0) {
/* Found JFIF "JFXX" extension APP0 marker */
/* The library doesn't actually do anything with these,
* but we try to produce a helpful trace message.
*/
switch (GETJOCTET(data[5])) {
case 0x10:
TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
break;
case 0x11:
TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
break;
case 0x13:
TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
break;
default:
TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
GETJOCTET(data[5]), (int) totallen);
break;
}
} else {
/* Start of APP0 does not match "JFIF" or "JFXX", or too short */
TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
}
}
LOCAL(void)
examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
unsigned int datalen, INT32 remaining)
/* Examine first few bytes from an APP14.
* Take appropriate action if it is an Adobe marker.
* datalen is # of bytes at data[], remaining is length of rest of marker data.
*/
{
unsigned int version, flags0, flags1, transform;
if (datalen >= APP14_DATA_LEN &&
GETJOCTET(data[0]) == 0x41 &&
GETJOCTET(data[1]) == 0x64 &&
GETJOCTET(data[2]) == 0x6F &&
GETJOCTET(data[3]) == 0x62 &&
GETJOCTET(data[4]) == 0x65) {
/* Found Adobe APP14 marker */
version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
transform = GETJOCTET(data[11]);
TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
cinfo->saw_Adobe_marker = TRUE;
cinfo->Adobe_transform = (UINT8) transform;
} else {
/* Start of APP14 does not match "Adobe", or too short */
TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
}
}
METHODDEF(boolean)
get_interesting_appn (j_decompress_ptr cinfo)
/* Process an APP0 or APP14 marker without saving it */
{
INT32 length;
JOCTET b[APPN_DATA_LEN];
unsigned int i, numtoread;
INPUT_VARS(cinfo);
INPUT_2BYTES(cinfo, length, return FALSE);
length -= 2;
/* get the interesting part of the marker data */
if (length >= APPN_DATA_LEN)
numtoread = APPN_DATA_LEN;
else if (length > 0)
numtoread = (unsigned int) length;
else
numtoread = 0;
for (i = 0; i < numtoread; i++)
INPUT_BYTE(cinfo, b[i], return FALSE);
length -= numtoread;
/* process it */
switch (cinfo->unread_marker) {
case M_APP0:
examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
break;
case M_APP14:
examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
break;
default:
/* can't get here unless jpeg_save_markers chooses wrong processor */
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
break;
}
/* skip any remaining data -- could be lots */
INPUT_SYNC(cinfo);
if (length > 0)
(*cinfo->src->skip_input_data) (cinfo, (long) length);
return TRUE;
}
#ifdef SAVE_MARKERS_SUPPORTED
METHODDEF(boolean)
save_marker (j_decompress_ptr cinfo)
/* Save an APPn or COM marker into the marker list */
{
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
unsigned int bytes_read, data_length;
JOCTET FAR * data;
INT32 length = 0;
INPUT_VARS(cinfo);
if (cur_marker == NULL) {
/* begin reading a marker */
INPUT_2BYTES(cinfo, length, return FALSE);
length -= 2;
if (length >= 0) { /* watch out for bogus length word */
/* figure out how much we want to save */
unsigned int limit;
if (cinfo->unread_marker == (int) M_COM)
limit = marker->length_limit_COM;
else
limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
if ((unsigned int) length < limit)
limit = (unsigned int) length;
/* allocate and initialize the marker item */
cur_marker = (jpeg_saved_marker_ptr)
(*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF(struct jpeg_marker_struct) + limit);
cur_marker->next = NULL;
cur_marker->marker = (UINT8) cinfo->unread_marker;
cur_marker->original_length = (unsigned int) length;
cur_marker->data_length = limit;
/* data area is just beyond the jpeg_marker_struct */
data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
marker->cur_marker = cur_marker;
marker->bytes_read = 0;
bytes_read = 0;
data_length = limit;
} else {
/* deal with bogus length word */
bytes_read = data_length = 0;
data = NULL;
}
} else {
/* resume reading a marker */
bytes_read = marker->bytes_read;
data_length = cur_marker->data_length;
data = cur_marker->data + bytes_read;
}
while (bytes_read < data_length) {
INPUT_SYNC(cinfo); /* move the restart point to here */
marker->bytes_read = bytes_read;
/* If there's not at least one byte in buffer, suspend */
MAKE_BYTE_AVAIL(cinfo, return FALSE);
/* Copy bytes with reasonable rapidity */
while (bytes_read < data_length && bytes_in_buffer > 0) {
*data++ = *next_input_byte++;
bytes_in_buffer--;
bytes_read++;
}
}
/* Done reading what we want to read */
if (cur_marker != NULL) { /* will be NULL if bogus length word */
/* Add new marker to end of list */
if (cinfo->marker_list == NULL) {
cinfo->marker_list = cur_marker;
} else {
jpeg_saved_marker_ptr prev = cinfo->marker_list;
while (prev->next != NULL)
prev = prev->next;
prev->next = cur_marker;
}
/* Reset pointer & calc remaining data length */
data = cur_marker->data;
length = cur_marker->original_length - data_length;
}
/* Reset to initial state for next marker */
marker->cur_marker = NULL;
/* Process the marker if interesting; else just make a generic trace msg */
switch (cinfo->unread_marker) {
case M_APP0:
examine_app0(cinfo, data, data_length, length);
break;
case M_APP14:
examine_app14(cinfo, data, data_length, length);
break;
default:
TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
(int) (data_length + length));
break;
}
/* skip any remaining data -- could be lots */
INPUT_SYNC(cinfo); /* do before skip_input_data */
if (length > 0)
(*cinfo->src->skip_input_data) (cinfo, (long) length);
return TRUE;
}
#endif /* SAVE_MARKERS_SUPPORTED */
METHODDEF(boolean)
skip_variable (j_decompress_ptr cinfo)
/* Skip over an unknown or uninteresting variable-length marker */
{
INT32 length;
INPUT_VARS(cinfo);
INPUT_2BYTES(cinfo, length, return FALSE);
length -= 2;
TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
INPUT_SYNC(cinfo); /* do before skip_input_data */
if (length > 0)
(*cinfo->src->skip_input_data) (cinfo, (long) length);
return TRUE;
}
/*
* Find the next JPEG marker, save it in cinfo->unread_marker.
* Returns FALSE if had to suspend before reaching a marker;
* in that case cinfo->unread_marker is unchanged.
*
* Note that the result might not be a valid marker code,
* but it will never be 0 or FF.
*/
LOCAL(boolean)
next_marker (j_decompress_ptr cinfo)
{
int c;
INPUT_VARS(cinfo);
for (;;) {
INPUT_BYTE(cinfo, c, return FALSE);
/* Skip any non-FF bytes.
* This may look a bit inefficient, but it will not occur in a valid file.
* We sync after each discarded byte so that a suspending data source
* can discard the byte from its buffer.
*/
while (c != 0xFF) {
cinfo->marker->discarded_bytes++;
INPUT_SYNC(cinfo);
INPUT_BYTE(cinfo, c, return FALSE);
}
/* This loop swallows any duplicate FF bytes. Extra FFs are legal as
* pad bytes, so don't count them in discarded_bytes. We assume there
* will not be so many consecutive FF bytes as to overflow a suspending
* data source's input buffer.
*/
do {
INPUT_BYTE(cinfo, c, return FALSE);
} while (c == 0xFF);
if (c != 0)
break; /* found a valid marker, exit loop */
/* Reach here if we found a stuffed-zero data sequence (FF/00).
* Discard it and loop back to try again.
*/
cinfo->marker->discarded_bytes += 2;
INPUT_SYNC(cinfo);
}
if (cinfo->marker->discarded_bytes != 0) {
WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
cinfo->marker->discarded_bytes = 0;
}
cinfo->unread_marker = c;
INPUT_SYNC(cinfo);
return TRUE;
}
LOCAL(boolean)
first_marker (j_decompress_ptr cinfo)
/* Like next_marker, but used to obtain the initial SOI marker. */
/* For this marker, we do not allow preceding garbage or fill; otherwise,
* we might well scan an entire input file before realizing it ain't JPEG.
* If an application wants to process non-JFIF files, it must seek to the
* SOI before calling the JPEG library.
*/
{
int c, c2;
INPUT_VARS(cinfo);
INPUT_BYTE(cinfo, c, return FALSE);
INPUT_BYTE(cinfo, c2, return FALSE);
if (c != 0xFF || c2 != (int) M_SOI)
ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
cinfo->unread_marker = c2;
INPUT_SYNC(cinfo);
return TRUE;
}
/*
* Read markers until SOS or EOI.
*
* Returns same codes as are defined for jpeg_consume_input:
* JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
*/
METHODDEF(int)
read_markers (j_decompress_ptr cinfo)
{
/* Outer loop repeats once for each marker. */
for (;;) {
/* Collect the marker proper, unless we already did. */
/* NB: first_marker() enforces the requirement that SOI appear first. */
if (cinfo->unread_marker == 0) {
if (! cinfo->marker->saw_SOI) {
if (! first_marker(cinfo))
return JPEG_SUSPENDED;
} else {
if (! next_marker(cinfo))
return JPEG_SUSPENDED;
}
}
/* At this point cinfo->unread_marker contains the marker code and the
* input point is just past the marker proper, but before any parameters.
* A suspension will cause us to return with this state still true.
*/
switch (cinfo->unread_marker) {
case M_SOI:
if (! get_soi(cinfo))
return JPEG_SUSPENDED;
break;
case M_SOF0: /* Baseline */
case M_SOF1: /* Extended sequential, Huffman */
if (! get_sof(cinfo, FALSE, FALSE))
return JPEG_SUSPENDED;
break;
case M_SOF2: /* Progressive, Huffman */
if (! get_sof(cinfo, TRUE, FALSE))
return JPEG_SUSPENDED;
break;
case M_SOF9: /* Extended sequential, arithmetic */
if (! get_sof(cinfo, FALSE, TRUE))
return JPEG_SUSPENDED;
break;
case M_SOF10: /* Progressive, arithmetic */
if (! get_sof(cinfo, TRUE, TRUE))
return JPEG_SUSPENDED;
break;
/* Currently unsupported SOFn types */
case M_SOF3: /* Lossless, Huffman */
case M_SOF5: /* Differential sequential, Huffman */
case M_SOF6: /* Differential progressive, Huffman */
case M_SOF7: /* Differential lossless, Huffman */
case M_JPG: /* Reserved for JPEG extensions */
case M_SOF11: /* Lossless, arithmetic */
case M_SOF13: /* Differential sequential, arithmetic */
case M_SOF14: /* Differential progressive, arithmetic */
case M_SOF15: /* Differential lossless, arithmetic */
ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
break;
case M_SOS:
if (! get_sos(cinfo))
return JPEG_SUSPENDED;
cinfo->unread_marker = 0; /* processed the marker */
return JPEG_REACHED_SOS;
case M_EOI:
TRACEMS(cinfo, 1, JTRC_EOI);
cinfo->unread_marker = 0; /* processed the marker */
return JPEG_REACHED_EOI;
case M_DAC:
if (! get_dac(cinfo))
return JPEG_SUSPENDED;
break;
case M_DHT:
if (! get_dht(cinfo))
return JPEG_SUSPENDED;
break;
case M_DQT:
if (! get_dqt(cinfo))
return JPEG_SUSPENDED;
break;
case M_DRI:
if (! get_dri(cinfo))
return JPEG_SUSPENDED;
break;
case M_APP0:
case M_APP1:
case M_APP2:
case M_APP3:
case M_APP4:
case M_APP5:
case M_APP6:
case M_APP7:
case M_APP8:
case M_APP9:
case M_APP10:
case M_APP11:
case M_APP12:
case M_APP13:
case M_APP14:
case M_APP15:
if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
cinfo->unread_marker - (int) M_APP0]) (cinfo))
return JPEG_SUSPENDED;
break;
case M_COM:
if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
return JPEG_SUSPENDED;
break;
case M_RST0: /* these are all parameterless */
case M_RST1:
case M_RST2:
case M_RST3:
case M_RST4:
case M_RST5:
case M_RST6:
case M_RST7:
case M_TEM:
TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
break;
case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
if (! skip_variable(cinfo))
return JPEG_SUSPENDED;
break;
default: /* must be DHP, EXP, JPGn, or RESn */
/* For now, we treat the reserved markers as fatal errors since they are
* likely to be used to signal incompatible JPEG Part 3 extensions.
* Once the JPEG 3 version-number marker is well defined, this code
* ought to change!
*/
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
break;
}
/* Successfully processed marker, so reset state variable */
cinfo->unread_marker = 0;
} /* end loop */
}
/*
* Read a restart marker, which is expected to appear next in the datastream;
* if the marker is not there, take appropriate recovery action.
* Returns FALSE if suspension is required.
*
* This is called by the entropy decoder after it has read an appropriate
* number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
* has already read a marker from the data source. Under normal conditions
* cinfo->unread_marker will be reset to 0 before returning; if not reset,
* it holds a marker which the decoder will be unable to read past.
*/
METHODDEF(boolean)
read_restart_marker (j_decompress_ptr cinfo)
{
/* Obtain a marker unless we already did. */
/* Note that next_marker will complain if it skips any data. */
if (cinfo->unread_marker == 0) {
if (! next_marker(cinfo))
return FALSE;
}
if (cinfo->unread_marker ==
((int) M_RST0 + cinfo->marker->next_restart_num)) {
/* Normal case --- swallow the marker and let entropy decoder continue */
TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
cinfo->unread_marker = 0;
} else {
/* Uh-oh, the restart markers have been messed up. */
/* Let the data source manager determine how to resync. */
if (! (*cinfo->src->resync_to_restart) (cinfo,
cinfo->marker->next_restart_num))
return FALSE;
}
/* Update next-restart state */
cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
return TRUE;
}
/*
* This is the default resync_to_restart method for data source managers
* to use if they don't have any better approach. Some data source managers
* may be able to back up, or may have additional knowledge about the data
* which permits a more intelligent recovery strategy; such managers would
* presumably supply their own resync method.
*
* read_restart_marker calls resync_to_restart if it finds a marker other than
* the restart marker it was expecting. (This code is *not* used unless
* a nonzero restart interval has been declared.) cinfo->unread_marker is
* the marker code actually found (might be anything, except 0 or FF).
* The desired restart marker number (0..7) is passed as a parameter.
* This routine is supposed to apply whatever error recovery strategy seems
* appropriate in order to position the input stream to the next data segment.
* Note that cinfo->unread_marker is treated as a marker appearing before
* the current data-source input point; usually it should be reset to zero
* before returning.
* Returns FALSE if suspension is required.
*
* This implementation is substantially constrained by wanting to treat the
* input as a data stream; this means we can't back up. Therefore, we have
* only the following actions to work with:
* 1. Simply discard the marker and let the entropy decoder resume at next
* byte of file.
* 2. Read forward until we find another marker, discarding intervening
* data. (In theory we could look ahead within the current bufferload,
* without having to discard data if we don't find the desired marker.
* This idea is not implemented here, in part because it makes behavior
* dependent on buffer size and chance buffer-boundary positions.)
* 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
* This will cause the entropy decoder to process an empty data segment,
* inserting dummy zeroes, and then we will reprocess the marker.
*
* #2 is appropriate if we think the desired marker lies ahead, while #3 is
* appropriate if the found marker is a future restart marker (indicating
* that we have missed the desired restart marker, probably because it got
* corrupted).
* We apply #2 or #3 if the found marker is a restart marker no more than
* two counts behind or ahead of the expected one. We also apply #2 if the
* found marker is not a legal JPEG marker code (it's certainly bogus data).
* If the found marker is a restart marker more than 2 counts away, we do #1
* (too much risk that the marker is erroneous; with luck we will be able to
* resync at some future point).
* For any valid non-restart JPEG marker, we apply #3. This keeps us from
* overrunning the end of a scan. An implementation limited to single-scan
* files might find it better to apply #2 for markers other than EOI, since
* any other marker would have to be bogus data in that case.
*/
GLOBAL(boolean)
jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
{
int marker = cinfo->unread_marker;
int action = 1;
/* Always put up a warning. */
WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
/* Outer loop handles repeated decision after scanning forward. */
for (;;) {
if (marker < (int) M_SOF0)
action = 2; /* invalid marker */
else if (marker < (int) M_RST0 || marker > (int) M_RST7)
action = 3; /* valid non-restart marker */
else {
if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
marker == ((int) M_RST0 + ((desired+2) & 7)))
action = 3; /* one of the next two expected restarts */
else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
marker == ((int) M_RST0 + ((desired-2) & 7)))
action = 2; /* a prior restart, so advance */
else
action = 1; /* desired restart or too far away */
}
TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
switch (action) {
case 1:
/* Discard marker and let entropy decoder resume processing. */
cinfo->unread_marker = 0;
return TRUE;
case 2:
/* Scan to the next marker, and repeat the decision loop. */
if (! next_marker(cinfo))
return FALSE;
marker = cinfo->unread_marker;
break;
case 3:
/* Return without advancing past this marker. */
/* Entropy decoder will be forced to process an empty segment. */
return TRUE;
}
} /* end loop */
}
/*
* Reset marker processing state to begin a fresh datastream.
*/
METHODDEF(void)
reset_marker_reader (j_decompress_ptr cinfo)
{
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
cinfo->comp_info = NULL; /* until allocated by get_sof */
cinfo->input_scan_number = 0; /* no SOS seen yet */
cinfo->unread_marker = 0; /* no pending marker */
marker->pub.saw_SOI = FALSE; /* set internal state too */
marker->pub.saw_SOF = FALSE;
marker->pub.discarded_bytes = 0;
marker->cur_marker = NULL;
}
/*
* Initialize the marker reader module.
* This is called only once, when the decompression object is created.
*/
GLOBAL(void)
jinit_marker_reader (j_decompress_ptr cinfo)
{
my_marker_ptr marker;
int i;
/* Create subobject in permanent pool */
marker = (my_marker_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
SIZEOF(my_marker_reader));
cinfo->marker = (struct jpeg_marker_reader *) marker;
/* Initialize public method pointers */
marker->pub.reset_marker_reader = reset_marker_reader;
marker->pub.read_markers = read_markers;
marker->pub.read_restart_marker = read_restart_marker;
/* Initialize COM/APPn processing.
* By default, we examine and then discard APP0 and APP14,
* but simply discard COM and all other APPn.
*/
marker->process_COM = skip_variable;
marker->length_limit_COM = 0;
for (i = 0; i < 16; i++) {
marker->process_APPn[i] = skip_variable;
marker->length_limit_APPn[i] = 0;
}
marker->process_APPn[0] = get_interesting_appn;
marker->process_APPn[14] = get_interesting_appn;
/* Reset marker processing state */
reset_marker_reader(cinfo);
}
/*
* Control saving of COM and APPn markers into marker_list.
*/
#ifdef SAVE_MARKERS_SUPPORTED
GLOBAL(void)
jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
unsigned int length_limit)
{
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
long maxlength;
jpeg_marker_parser_method processor;
/* Length limit mustn't be larger than what we can allocate
* (should only be a concern in a 16-bit environment).
*/
maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
if (((long) length_limit) > maxlength)
length_limit = (unsigned int) maxlength;
/* Choose processor routine to use.
* APP0/APP14 have special requirements.
*/
if (length_limit) {
processor = save_marker;
/* If saving APP0/APP14, save at least enough for our internal use. */
if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
length_limit = APP0_DATA_LEN;
else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
length_limit = APP14_DATA_LEN;
} else {
processor = skip_variable;
/* If discarding APP0/APP14, use our regular on-the-fly processor. */
if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
processor = get_interesting_appn;
}
if (marker_code == (int) M_COM) {
marker->process_COM = processor;
marker->length_limit_COM = length_limit;
} else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
marker->process_APPn[marker_code - (int) M_APP0] = processor;
marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
} else
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
}
#endif /* SAVE_MARKERS_SUPPORTED */
/*
* Install a special processing method for COM or APPn markers.
*/
GLOBAL(void)
jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
jpeg_marker_parser_method routine)
{
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
if (marker_code == (int) M_COM)
marker->process_COM = routine;
else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
marker->process_APPn[marker_code - (int) M_APP0] = routine;
else
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
}