JPWL - JPEG-2000 Part11 (JPWL) codestream manager

Data Structures
struct	jpwl_epb_ms
	EPB (Error Protection Block) Marker segment. More...
struct	jpwl_epc_ms
	EPC (Error Protection Capability) Marker segment. More...
struct	jpwl_esd_ms
	ESD (Error Sensitivity Descriptor) Marker segment. More...
struct	jpwl_red_ms
	RED (Residual Error Descriptor) Marker segment. More...
struct	jpwl_marker
	Structure used to store JPWL markers temporary position and readyness. More...
Defines
#define	JPWL_ASSUME   true
	Assume a basic codestream structure, so you can resort better from uncorrected errors.
#define	jpwl_updateCRC16(CRC, DATA)   updateCRC16(CRC, DATA)
	Macro functions for CRC computation.
#define	jpwl_updateCRC32(CRC, DATA)   updateCRC32(CRC, DATA)
	Computes the CRC-32, as stated in JPWL specs.
#define	min(a, b)   (((a) < (b)) ? (a) : (b))
	Computes the minimum between two integers.
Typedefs
typedef struct jpwl_epb_ms	jpwl_epb_ms_t
	EPB (Error Protection Block) Marker segment.
typedef struct jpwl_epc_ms	jpwl_epc_ms_t
	EPC (Error Protection Capability) Marker segment.
typedef struct jpwl_esd_ms	jpwl_esd_ms_t
	ESD (Error Sensitivity Descriptor) Marker segment.
typedef struct jpwl_red_ms	jpwl_red_ms_t
	RED (Residual Error Descriptor) Marker segment.
typedef struct jpwl_marker	jpwl_marker_t
	Structure used to store JPWL markers temporary position and readyness.
Functions
void	jpwl_encode (opj_j2k_t *j2k, opj_cio_t *cio, opj_image_t *image)
	Encode according to JPWL specs.
void	jpwl_prepare_marks (opj_j2k_t *j2k, opj_cio_t *cio, opj_image_t *image)
	Prepare the list of JPWL markers, after the Part 1 codestream has been finalized (index struct is full).
void	jpwl_dump_marks (opj_j2k_t *j2k, opj_cio_t *cio, opj_image_t *image)
	Dump the list of JPWL markers, after it has been prepared.
void	j2k_read_epc (opj_j2k_t *j2k)
	Read the EPC marker (Error Protection Capability).
void	j2k_write_epc (opj_j2k_t *j2k)
	Write the EPC marker (Error Protection Capability), BUT the DL field is always set to 0 (this simplifies the management of EPBs and it is openly stated in the standard as a possible value, mening that the information is not available) and the informative techniques are not yet implemented.
void	j2k_read_epb (opj_j2k_t *j2k)
	Read the EPB marker (Error Protection Block).
void	j2k_write_epb (opj_j2k_t *j2k)
	Write the EPB marker (Error Protection Block).
void	j2k_read_esd (opj_j2k_t *j2k)
	Read the ESD marker (Error Sensitivity Descriptor).
void	j2k_read_red (opj_j2k_t *j2k)
	Read the RED marker (Residual Error Descriptor).
jpwl_epb_ms_t *	jpwl_epb_create (opj_j2k_t *j2k, bool latest, bool packed, int tileno, int idx, int hprot, unsigned long int pre_len, unsigned long int post_len)
	create an EPB marker segment
int	jpwl_epbs_add (opj_j2k_t *j2k, jpwl_marker_t *jwmarker, int *jwmarker_num, bool latest, bool packed, bool insideMH, int *idx, int hprot, double place_pos, int tileno, unsigned long int pre_len, unsigned long int post_len)
	add a number of EPB marker segments
int	jpwl_esds_add (opj_j2k_t *j2k, jpwl_marker_t *jwmarker, int *jwmarker_num, int comps, unsigned char addrm, unsigned char ad_size, unsigned char senst, unsigned char se_size, double place_pos, int tileno)
	add a number of ESD marker segments
bool	jpwl_update_info (opj_j2k_t *j2k, jpwl_marker_t *jwmarker, int jwmarker_num)
	updates the information structure by modifying the positions and lengths
bool	jpwl_esd_fill (opj_j2k_t *j2k, jpwl_esd_ms_t *esdmark, unsigned char *buf)
bool	jpwl_epb_fill (opj_j2k_t *j2k, jpwl_epb_ms_t *epbmark, unsigned char *buf, unsigned char *post_buf)
void	j2k_add_marker (opj_codestream_info_t *cstr_info, unsigned short int type, int pos, int len)
bool	jpwl_correct (opj_j2k_t *j2k)
	corrects the data in the JPWL codestream
bool	jpwl_epb_correct (opj_j2k_t *j2k, unsigned char *buffer, int type, int pre_len, int post_len, int *conn, unsigned char **L4_bufp)
	corrects the data protected by an EPB
bool	jpwl_check_tile (opj_j2k_t *j2k, opj_tcd_t *tcd, int tileno)
	check that a tile and its children have valid data
Local static variables
static int	jwmarker_num
	number of JPWL prepared markers
static jpwl_marker_t	jwmarker [JPWL_MAX_NO_MARKERS]
	properties of JPWL markers to insert

---

Define Documentation

#define JPWL_ASSUME   true

Assume a basic codestream structure, so you can resort better from uncorrected errors.

Referenced by j2k_decode(), j2k_read_ppm(), j2k_read_qcc(), j2k_read_qcx(), j2k_read_rgn(), j2k_read_siz(), j2k_read_sot(), j2k_read_unk(), jpwl_check_tile(), and t2_decode_packet().

#define jpwl_updateCRC16	(	CRC,
		DATA		)	updateCRC16(CRC, DATA)

Macro functions for CRC computation.

Computes the CRC-16, as stated in JPWL specs

Parameters:

CRC

two bytes containing the CRC value (must be initialized with 0x0000) Parameters: DATA  byte for which the CRC is computed; call this on every byte of the sequence and get the CRC at the end

Referenced by j2k_read_epc(), j2k_write_epc(), jpwl_dump_marks(), jpwl_epb_correct(), and jpwl_epb_fill().

#define jpwl_updateCRC32	(	CRC,
		DATA		)	updateCRC32(CRC, DATA)

Computes the CRC-32, as stated in JPWL specs.

Parameters:

CRC

four bytes containing the CRC value (must be initialized with 0x00000000) Parameters: DATA  byte for which the CRC is computed; call this on every byte of the sequence and get the CRC at the end

Referenced by jpwl_epb_correct(), and jpwl_epb_fill().

#define min	(	a,
		b		)	(((a) < (b)) ? (a) : (b))

Computes the minimum between two integers.

Parameters:

a

first integer to compare Parameters: b  second integer to compare Returns: returns the minimum integer between a and b

Referenced by eras_dec_rs(), jpwl_epbs_add(), tcd_decode_tile(), and tcd_rateallocate().

---

Typedef Documentation

typedef struct jpwl_epb_ms jpwl_epb_ms_t

EPB (Error Protection Block) Marker segment.

typedef struct jpwl_epc_ms jpwl_epc_ms_t

EPC (Error Protection Capability) Marker segment.

typedef struct jpwl_esd_ms jpwl_esd_ms_t

ESD (Error Sensitivity Descriptor) Marker segment.

typedef struct jpwl_marker jpwl_marker_t

Structure used to store JPWL markers temporary position and readyness.

typedef struct jpwl_red_ms jpwl_red_ms_t

RED (Residual Error Descriptor) Marker segment.

---

Function Documentation

void j2k_add_marker	(	opj_codestream_info_t *	cstr_info,
		unsigned short int	type,
		int	pos,
		int	len
	)

References opj_marker_info_t::len, opj_codestream_info::marker, opj_codestream_info::marknum, opj_codestream_info::maxmarknum, opj_realloc, opj_marker_info_t::pos, and opj_marker_info_t::type.

Referenced by j2k_write_eoc(), j2k_write_epb(), j2k_write_epc(), j2k_write_soc(), j2k_write_sod(), j2k_write_sot(), jpwl_epb_write(), jpwl_epc_write(), and jpwl_esd_write().

void j2k_read_epb

(

opj_j2k_t *

j2k

)

Read the EPB marker (Error Protection Block).

Parameters:

j2k

J2K handle

References opj_cio::bp, opj_j2k::cinfo, opj_j2k::cio, cio_read(), cio_seek(), cio_skip(), cio_tell(), opj_cp::correct, opj_j2k::cp, EVT_ERROR, EVT_INFO, opj_cp::exp_comps, J2K_STATE_MH, J2K_STATE_TPH, jpwl_epb_correct(), opj_event_msg(), and opj_j2k::state.

void j2k_read_epc

(

opj_j2k_t *

j2k

)

Read the EPC marker (Error Protection Capability).

Parameters:

j2k

J2K handle

References opj_j2k::cinfo, opj_j2k::cio, cio_read(), cio_seek(), cio_skip(), cio_tell(), EVT_INFO, jpwl_updateCRC16, and opj_event_msg().

void j2k_read_esd

(

opj_j2k_t *

j2k

)

Read the ESD marker (Error Sensitivity Descriptor).

Parameters:

j2k

J2K handle

References opj_j2k::cinfo, opj_j2k::cio, cio_read(), cio_skip(), cio_tell(), EVT_INFO, opj_j2k::image, opj_image::numcomps, and opj_event_msg().

void j2k_read_red

(

opj_j2k_t *

j2k

)

Read the RED marker (Residual Error Descriptor).

Parameters:

j2k

J2K handle

References opj_j2k::cinfo, opj_j2k::cio, cio_read(), cio_skip(), cio_tell(), EVT_INFO, and opj_event_msg().

void j2k_write_epb

(

opj_j2k_t *

j2k

)

Write the EPB marker (Error Protection Block).

Parameters:

j2k

J2K handle

References opj_j2k::cio, cio_seek(), cio_skip(), cio_tell(), cio_write(), opj_j2k::cstr_info, j2k_add_marker(), and J2K_MS_EPB.

void j2k_write_epc

(

opj_j2k_t *

j2k

)

Write the EPC marker (Error Protection Capability), BUT the DL field is always set to 0 (this simplifies the management of EPBs and it is openly stated in the standard as a possible value, mening that the information is not available) and the informative techniques are not yet implemented.

Parameters:

j2k

J2K handle

References opj_j2k::cio, cio_read(), cio_seek(), cio_skip(), cio_tell(), cio_write(), opj_j2k::cstr_info, j2k_add_marker(), J2K_MS_EPC, and jpwl_updateCRC16.

bool jpwl_check_tile	(	opj_j2k_t *	j2k,
		opj_tcd_t *	tcd,
		int	tileno
	)

check that a tile and its children have valid data

Parameters:

j2k

J2K decompressor handle Parameters: tcd  Tile decompressor handle Parameters: tileno  number of the tile to check

References opj_tcd_resolution::bands, opj_tcd_precinct::cblks, opj_tcd_precinct::ch, opj_j2k::cinfo, opj_tcd_tile::comps, opj_tcd_precinct::cw, EVT_ERROR, EVT_WARNING, JPWL_ASSUME, opj_tcd_resolution::numbands, opj_tcd_tile::numcomps, opj_tcd_tilecomp::numresolutions, opj_event_msg(), opj_tcd_resolution::ph, opj_tcd_band::precincts, opj_tcd_resolution::pw, opj_tcd_tilecomp::resolutions, opj_tcd::tcd_image, opj_tcd_image::tiles, opj_tcd_precinct::x0, and opj_tcd_precinct::x1.

bool jpwl_correct

(

opj_j2k_t *

j2k

)

corrects the data in the JPWL codestream

Parameters:

j2k

J2K compressor handle Returns: true if correction is performed correctly

References opj_cio::bp, opj_j2k::cio, cio_read(), cio_seek(), cio_skip(), cio_tell(), opj_j2k::cp, opj_cio::end, opj_cp::exp_comps, J2K_MS_EOC, J2K_MS_EPB, J2K_MS_SIZ, J2K_MS_SOC, J2K_MS_SOD, J2K_MS_SOT, J2K_STATE_MH, J2K_STATE_MHSIZ, J2K_STATE_MHSOC, J2K_STATE_MT, J2K_STATE_TPH, jpwl_epb_correct(), opj_cio::length, and opj_j2k::state.

Referenced by j2k_decode().

void jpwl_dump_marks	(	opj_j2k_t *	j2k,
		opj_cio_t *	cio,
		opj_image_t *	image
	)

Dump the list of JPWL markers, after it has been prepared.

Parameters:

j2k

J2K handle Parameters: cio  codestream handle Parameters: image  image handle

References opj_cio::bp, opj_cio::buffer, opj_cio::cinfo, opj_j2k::cinfo, cio_getbp(), cio_seek(), cio_tell(), opj_codestream_info::codestream_size, opj_j2k::cp, opj_j2k::cstr_info, opj_cio::end, opj_cp::epb_on, opj_cp::esd_on, EVT_ERROR, EVT_INFO, J2K_MS_EPB, J2K_MS_EPC, J2K_MS_ESD, J2K_MS_RED, jpwl_epb_fill(), jpwl_epb_write(), jpwl_epc_write(), jpwl_esd_fill(), jpwl_esd_write(), jpwl_markcomp(), jpwl_update_info(), jpwl_updateCRC16, jwmarker_num, opj_cio::length, opj_codestream_info::main_head_start, opj_codestream_info::marker, opj_codestream_info::marknum, opj_cio::openmode, opj_clock(), opj_event_msg(), opj_free, opj_malloc, opj_marker_info_t::pos, and opj_cio::start.

Referenced by jpwl_encode().

void jpwl_encode	(	opj_j2k_t *	j2k,
		opj_cio_t *	cio,
		opj_image_t *	image
	)

Encode according to JPWL specs.

Parameters:

j2k

J2K handle Parameters: cio  codestream handle Parameters: image  image handle

References J2K_MS_EPB, J2K_MS_EPC, J2K_MS_ESD, J2K_MS_RED, jpwl_dump_marks(), JPWL_MAX_NO_MARKERS, jpwl_prepare_marks(), jwmarker_num, and opj_j2k::pos_correction.

Referenced by j2k_encode().

bool jpwl_epb_correct	(	opj_j2k_t *	j2k,
		unsigned char *	buffer,
		int	type,
		int	pre_len,
		int	post_len,
		int *	conn,
		unsigned char **	L4_bufp
	)

corrects the data protected by an EPB

Parameters:

j2k

J2K compressor handle Parameters: buffer  pointer to the EPB position Parameters: type  type of EPB: 0=MH, 1=TPH, 2=other, 3=auto Parameters: pre_len  length of pre-data Parameters: post_len  length of post_data Parameters: conn  is a pointer to the length of all connected (packed) EPBs Parameters: L4_bufp  is a pointer to the buffer pointer of redundancy data Returns: returns true if correction could be succesfully performed

References opj_cio::bp, opj_j2k::cinfo, opj_j2k::cio, cio_numbytesleft(), cio_read(), cio_seek(), cio_skip(), cio_tell(), eras_dec_rs(), EVT_ERROR, EVT_INFO, EVT_WARNING, init_rs(), jpwl_epb_correct(), jpwl_updateCRC16, jpwl_updateCRC32, NN, and opj_event_msg().

Referenced by j2k_read_epb(), jpwl_correct(), and jpwl_epb_correct().

jpwl_epb_ms_t* jpwl_epb_create	(	opj_j2k_t *	j2k,
		bool	latest,
		bool	packed,
		int	tileno,
		int	idx,
		int	hprot,
		unsigned long int	pre_len,
		unsigned long int	post_len
	)

create an EPB marker segment

Parameters:

j2k

J2K compressor handle Parameters: latest  it is the latest EPB in the header Parameters: packed  EPB is in packed style Parameters: tileno  tile number where the marker has been placed (-1 means MH) Parameters: idx  current EPB running index Parameters: hprot  applied protection type (-1/0,1,16,32,37-128) Parameters: pre_len  length of pre-protected data Parameters: post_len  length of post-protected data Returns: returns the freshly created EPB

References opj_j2k::cinfo, jpwl_epb_ms::Depb, EVT_ERROR, jpwl_epb_ms::hprot, jpwl_epb_ms::k_post, jpwl_epb_ms::k_pre, jpwl_epb_ms::LDPepb, jpwl_epb_ms::Lepb, jpwl_epb_ms::n_post, jpwl_epb_ms::n_pre, opj_event_msg(), opj_malloc, jpwl_epb_ms::Pepb, jpwl_epb_ms::post_len, jpwl_epb_ms::pre_len, and jpwl_epb_ms::tileno.

Referenced by jpwl_epbs_add(), and jpwl_prepare_marks().

bool jpwl_epb_fill	(	opj_j2k_t *	j2k,
		jpwl_epb_ms_t *	epbmark,
		unsigned char *	buf,
		unsigned char *	post_buf
	)

References opj_j2k::cinfo, encode_rs(), EVT_ERROR, EVT_WARNING, jpwl_epb_ms::hprot, init_rs(), jpwl_updateCRC16, jpwl_updateCRC32, jpwl_epb_ms::k_post, jpwl_epb_ms::k_pre, jpwl_epb_ms::Lepb, jpwl_epb_ms::n_post, jpwl_epb_ms::n_pre, NN, opj_event_msg(), jpwl_epb_ms::post_len, and jpwl_epb_ms::pre_len.

Referenced by jpwl_dump_marks().

int jpwl_epbs_add	(	opj_j2k_t *	j2k,
		jpwl_marker_t *	jwmarker,
		int *	jwmarker_num,
		bool	latest,
		bool	packed,
		bool	insideMH,
		int *	idx,
		int	hprot,
		double	place_pos,
		int	tileno,
		unsigned long int	pre_len,
		unsigned long int	post_len
	)

add a number of EPB marker segments

Parameters:

j2k

J2K compressor handle Parameters: jwmarker  pointer to the JPWL markers list Parameters: jwmarker_num  pointer to the number of JPWL markers (gets updated) Parameters: latest  it is the latest group of EPBs in the header Parameters: packed  EPBs are in packed style Parameters: insideMH  it is in the MH Parameters: idx  pointer to the starting EPB running index (gets updated) Parameters: hprot  applied protection type (-1/0,1,16,32,37-128) Parameters: place_pos  place in original codestream where EPBs should go Parameters: tileno  tile number of these EPBs Parameters: pre_len  length of pre-protected data Parameters: post_len  length of post-protected data Returns: returns the length of all added markers

References opj_j2k::cinfo, jpwl_marker::data_ready, jpwl_marker::dpos, jpwl_marker::epbmark, EVT_ERROR, jpwl_marker::id, J2K_MS_EPB, jpwl_epb_create(), JPWL_MAX_NO_MARKERS, JPWL_MAXIMUM_EPB_ROOM, jpwl_marker::len, jpwl_marker::len_ready, jpwl_epb_ms::Lepb, min, opj_event_msg(), jpwl_marker::parms_ready, jpwl_marker::pos, and jpwl_marker::pos_ready.

Referenced by jpwl_prepare_marks().

bool jpwl_esd_fill	(	opj_j2k_t *	j2k,
		jpwl_esd_ms_t *	esdmark,
		unsigned char *	buf
	)

References jpwl_esd_ms::ad_size, jpwl_esd_ms::addrm, opj_image_comp::bpp, opj_j2k::cinfo, opj_image::comps, opj_j2k::cstr_info, jpwl_esd_ms::data, opj_packet_info::disto, opj_tile_info::distotile, opj_tile_info::end_header, opj_packet_info::end_pos, EVT_WARNING, opj_j2k::image, jpwl_double_to_pfp(), jpwl_pfp_to_double(), opj_codestream_info::main_head_end, MAX_V1, jpwl_esd_ms::numcomps, opj_image::numcomps, opj_tile_info::numpix, opj_event_msg(), opj_tile_info::packet, opj_codestream_info::packno, jpwl_esd_ms::se_size, jpwl_esd_ms::senst, opj_image_comp::sgnd, opj_tile_info::start_pos, opj_packet_info::start_pos, jpwl_esd_ms::svalnum, opj_codestream_info::th, opj_codestream_info::tile, jpwl_esd_ms::tileno, and opj_codestream_info::tw.

Referenced by jpwl_dump_marks().

int jpwl_esds_add	(	opj_j2k_t *	j2k,
		jpwl_marker_t *	jwmarker,
		int *	jwmarker_num,
		int	comps,
		unsigned char	addrm,
		unsigned char	ad_size,
		unsigned char	senst,
		unsigned char	se_size,
		double	place_pos,
		int	tileno
	)

add a number of ESD marker segments

Parameters:

j2k

J2K compressor handle Parameters: jwmarker  pointer to the JPWL markers list Parameters: jwmarker_num  pointer to the number of JPWL markers (gets updated) Parameters: comps  considered component (-1=average, 0/1/2/...=component no.) Parameters: addrm  addressing mode (0=packet, 1=byte range, 2=packet range, 3=reserved) Parameters: ad_size  size of addresses (2/4 bytes) Parameters: senst  sensitivity type Parameters: se_size  sensitivity values size (1/2 bytes) Parameters: place_pos  place in original codestream where EPBs should go Parameters: tileno  tile number of these EPBs Returns: returns the length of all added markers

void jpwl_prepare_marks	(	opj_j2k_t *	j2k,
		opj_cio_t *	cio,
		opj_image_t *	image
	)

Prepare the list of JPWL markers, after the Part 1 codestream has been finalized (index struct is full).

Parameters:

j2k

J2K handle Parameters: cio  codestream handle Parameters: image  image handle

References opj_j2k::cinfo, cio_getbp(), cio_read(), cio_seek(), cio_skip(), cio_tell(), cio_write(), opj_j2k::cp, opj_j2k::cstr_info, jpwl_marker::data_ready, jpwl_epb_ms::Depb, jpwl_marker::dpos, opj_packet_info::end_pos, opj_cp::epb_on, jpwl_marker::epbmark, jpwl_marker::epcmark, opj_cp::esd_on, jpwl_marker::esdmark, EVT_ERROR, EVT_INFO, opj_cp::hprot_MH, opj_cp::hprot_TPH, opj_cp::hprot_TPH_tileno, jpwl_marker::id, J2K_MS_EPB, J2K_MS_EPC, J2K_MS_ESD, jpwl_epb_create(), jpwl_epbs_add(), jpwl_epc_create(), jpwl_esd_create(), JPWL_MAX_NO_MARKERS, JPWL_MAX_NO_PACKSPECS, JPWL_MAX_NO_TILESPECS, jwmarker_num, jpwl_marker::len, jpwl_marker::len_ready, jpwl_epb_ms::Lepb, jpwl_epc_ms::Lepc, jpwl_esd_ms::Lesd, opj_codestream_info::main_head_end, opj_codestream_info::main_head_start, opj_tile_info::num_tps, opj_event_msg(), opj_tile_info::packet, opj_codestream_info::packno, jpwl_marker::parms_ready, jpwl_marker::pos, jpwl_marker::pos_ready, opj_cp::pprot, opj_cp::pprot_packno, opj_cp::pprot_tileno, opj_cp::red_on, opj_cp::sens_addr, opj_cp::sens_MH, opj_cp::sens_range, opj_cp::sens_size, opj_cp::sens_TPH, opj_cp::sens_TPH_tileno, opj_packet_info::start_pos, opj_codestream_info::th, opj_codestream_info::tile, opj_tile_info::tp, opj_tp_info::tp_end_header, opj_tp_info::tp_numpacks, opj_tp_info::tp_start_pack, opj_tp_info::tp_start_pos, and opj_codestream_info::tw.

Referenced by jpwl_encode().

bool jpwl_update_info	(	opj_j2k_t *	j2k,
		jpwl_marker_t *	jwmarker,
		int	jwmarker_num
	)

updates the information structure by modifying the positions and lengths

Parameters:

j2k

J2K compressor handle Parameters: jwmarker  pointer to JPWL markers list Parameters: jwmarker_num  number of JPWL markers Returns: returns true in case of success

References opj_j2k::cinfo, opj_codestream_info::codestream_size, opj_j2k::cstr_info, opj_tile_info::end_header, opj_packet_info::end_ph_pos, opj_packet_info::end_pos, opj_tile_info::end_pos, EVT_ERROR, jpwl_marker::len, opj_codestream_info::main_head_end, opj_tile_info::num_tps, opj_event_msg(), opj_tile_info::packet, opj_codestream_info::packno, opj_packet_info::start_pos, opj_tile_info::start_pos, opj_codestream_info::th, opj_codestream_info::tile, opj_tile_info::tp, opj_tp_info::tp_end_header, opj_tp_info::tp_end_pos, opj_tp_info::tp_start_pos, and opj_codestream_info::tw.

Referenced by jpwl_dump_marks().

---

Variable Documentation

jpwl_marker_t jwmarker[JPWL_MAX_NO_MARKERS] [static]

properties of JPWL markers to insert

int jwmarker_num [static]

number of JPWL prepared markers

Referenced by jpwl_dump_marks(), jpwl_encode(), and jpwl_prepare_marks().