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jdmarker.c
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/*
* jdmarker.c
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1991-1998, Thomas G. Lane.
* libjpeg-turbo Modifications:
* Copyright (C) 2012, 2015, 2022, D. R. Commander.
* For conditions of distribution and use, see the accompanying README.ijg
* 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 = *next_input_byte++; )
/* As above, but read two bytes interpreted as an unsigned 16-bit integer.
* V should be declared unsigned int or perhaps JLONG.
*/
#define INPUT_2BYTES(cinfo, V, action) \
MAKESTMT( MAKE_BYTE_AVAIL(cinfo, action); \
bytes_in_buffer--; \
V = ((unsigned int)(*next_input_byte++)) << 8; \
MAKE_BYTE_AVAIL(cinfo, action); \
bytes_in_buffer--; \
V += *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 */
{
JLONG 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 */
{
JLONG length;
int i, ci, n, c, cc, pi;
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 < MAX_COMPS_IN_SCAN; i++)
cinfo->cur_comp_info[i] = NULL;
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 < MAX_COMPS_IN_SCAN;
ci++, compptr++) {
if (cc == compptr->component_id && !cinfo->cur_comp_info[ci])
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);
/* This CSi (cc) should differ from the previous CSi */
for (pi = 0; pi < i; pi++) {
if (cinfo->cur_comp_info[pi] == compptr) {
ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
}
}
}
/* 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 */
{
JLONG 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 */
{
JLONG 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 || ((JLONG)count) > length)
ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
for (i = 0; i < count; i++)
INPUT_BYTE(cinfo, huffval[i], return FALSE);
memset(&huffval[count], 0, (256 - count) * sizeof(UINT8));
length -= count;
if (index & 0x10) { /* AC table definition */
index -= 0x10;
if (index < 0 || index >= NUM_HUFF_TBLS)
ERREXIT1(cinfo, JERR_DHT_INDEX, index);
htblptr = &cinfo->ac_huff_tbl_ptrs[index];
} else { /* DC table definition */
if (index < 0 || index >= NUM_HUFF_TBLS)
ERREXIT1(cinfo, JERR_DHT_INDEX, index);
htblptr = &cinfo->dc_huff_tbl_ptrs[index];
}
if (*htblptr == NULL)
*htblptr = jpeg_alloc_huff_table((j_common_ptr)cinfo);
memcpy((*htblptr)->bits, bits, sizeof((*htblptr)->bits));
memcpy((*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 */
{
JLONG 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 */
{
JLONG 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 *data, unsigned int datalen,
JLONG 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.
*/
{
JLONG totallen = (JLONG)datalen + remaining;
if (datalen >= APP0_DATA_LEN &&
data[0] == 0x4A &&
data[1] == 0x46 &&
data[2] == 0x49 &&
data[3] == 0x46 &&
data[4] == 0) {
/* Found JFIF APP0 marker: save info */
cinfo->saw_JFIF_marker = TRUE;
cinfo->JFIF_major_version = data[5];
cinfo->JFIF_minor_version = data[6];
cinfo->density_unit = data[7];
cinfo->X_density = (data[8] << 8) + data[9];
cinfo->Y_density = (data[10] << 8) + 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 (data[12] | data[13])
TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, data[12], data[13]);
totallen -= APP0_DATA_LEN;
if (totallen != ((JLONG)data[12] * (JLONG)data[13] * (JLONG)3))
TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int)totallen);
} else if (datalen >= 6 &&
data[0] == 0x4A &&
data[1] == 0x46 &&
data[2] == 0x58 &&
data[3] == 0x58 &&
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 (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, 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 *data, unsigned int datalen,
JLONG 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 &&
data[0] == 0x41 &&
data[1] == 0x64 &&
data[2] == 0x6F &&
data[3] == 0x62 &&
data[4] == 0x65) {
/* Found Adobe APP14 marker */
version = (data[5] << 8) + data[6];
flags0 = (data[7] << 8) + data[8];
flags1 = (data[9] << 8) + data[10];
transform = 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 */
{
JLONG 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 *)b, numtoread, length);
break;
case M_APP14:
examine_app14(cinfo, (JOCTET *)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 *data;
JLONG 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 *)(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 */
{
JLONG 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;