/* wrap jpeg libray for write
 *
 * 28/11/03 JC
 *	- better no-overshoot on tile loop
 * 12/11/04
 *	- better demand size choice for eval
 * 30/6/05 JC
 *	- update im_error()/im_warn()
 *	- now loads and saves exif data
 * 30/7/05
 * 	- now loads ICC profiles
 * 	- now saves ICC profiles from the VIPS header
 * 24/8/05
 * 	- jpeg load sets vips xres/yres from exif, if possible
 * 	- jpeg save sets exif xres/yres from vips, if possible
 * 29/8/05
 * 	- cut from old vips_jpeg.c
 * 20/4/06
 * 	- auto convert to sRGB/mono for save
 * 13/10/06
 * 	- add </libexif/ prefix if required
 * 19/1/07
 * 	- oop, libexif confusion
 * 2/11/07
 * 	- use im_wbuffer() API for BG writes
 * 15/2/08
 * 	- write CMYK if Bands == 4 and Type == CMYK
 * 12/5/09
 *	- fix signed/unsigned warning
 * 13/8/09
 * 	- allow "none" for profile, meaning don't embed one
 * 4/2/10
 * 	- gtkdoc
 * 17/7/10
 * 	- use g_assert()
 * 	- allow space for the header in init_destination(), helps writing very
 * 	  small JPEGs (thanks Tim Elliott)
 * 18/7/10
 * 	- collect im_vips2bufjpeg() output in a list of blocks ... we no
 * 	  longer overallocate or underallocate
 * 8/7/11
 * 	- oop CMYK write was not inverting, thanks Ole
 * 12/10/2011
 * 	- write XMP data
 * 18/10/2011
 * 	- update Orientation as well
 * 3/11/11
 * 	- rebuild exif tags from coded metadata values 
 * 24/11/11
 * 	- turn into a set of write fns ready to be called from a class
 * 7/8/12
 * 	- use VIPS_META_RESOLUTION_UNIT to select resolution unit
 * 16/11/12
 * 	- read ifds from exif fields 
 * 	- optionally parse rationals as a/b
 * 	- update exif image dimensions
 * 21/11/12
 * 	- attach IPCT data (app13), thanks Gary
 * 2/10/13 Lovell Fuller
 * 	- add optimize_coding parameter
 * 	- add progressive mode
 * 12/11/13
 * 	- add "strip" option to remove all metadata
 * 13/11/13
 * 	- add a "no_subsample" option to disable chroma subsample
 * 9/9/14
 * 	- support "none" as a resolution unit
 * 8/7/15
 * 	- omit oversized jpeg markers
 * 15/7/15
 * 	- exif tags use @name, not @title
 * 	- set arbitrary exif tags from metadata
 * 25/11/15	
 * 	- don't write JFIF headers if we are stripping, thanks Benjamin
 * 13/4/16
 * 	- remove deleted exif fields more carefully
 * 9/5/16 felixbuenemann
 * 	- add quant_table
 * 26/5/16
 * 	- switch to new orientation tag
 * 9/7/16
 * 	- turn off chroma subsample for Q > 90
 */

/*

    This file is part of VIPS.
    
    VIPS is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301  USA

 */

/*

    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk

 */

/*
#define DEBUG
#define VIPS_DEBUG
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>

#ifdef HAVE_JPEG

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <setjmp.h>
#include <math.h>

#include <vips/vips.h>
#include <vips/debug.h>

#ifdef HAVE_EXIF
#ifdef UNTAGGED_EXIF
#include <exif-data.h>
#include <exif-loader.h>
#include <exif-ifd.h>
#include <exif-utils.h>
#else /*!UNTAGGED_EXIF*/
#include <libexif/exif-data.h>
#include <libexif/exif-loader.h>
#include <libexif/exif-ifd.h>
#include <libexif/exif-utils.h>
#endif /*UNTAGGED_EXIF*/
#endif /*HAVE_EXIF*/

#include "jpeg.h"
#include "vipsjpeg.h"

/* New output message method - send to VIPS.
 */
void
vips__new_output_message( j_common_ptr cinfo )
{
	char buffer[JMSG_LENGTH_MAX];

	(*cinfo->err->format_message)( cinfo, buffer );
	vips_error( "VipsJpeg", _( "%s" ), buffer );

#ifdef DEBUG
	printf( "vips__new_output_message: \"%s\"\n", buffer );
#endif /*DEBUG*/
}

/* New error_exit handler.
 */
void
vips__new_error_exit( j_common_ptr cinfo )
{
	ErrorManager *eman = (ErrorManager *) cinfo->err;

#ifdef DEBUG
	printf( "vips__new_error_exit:\n" );
#endif /*DEBUG*/

	/* Close the fp if necessary.
	 */
	if( eman->fp ) {
		(void) fclose( eman->fp );
		eman->fp = NULL;
	}

	/* Send the error message to VIPS. This method is overridden above.
	 */
	(*cinfo->err->output_message)( cinfo );

	/* Jump back.
	 */
	longjmp( eman->jmp, 1 );
}

/* What we track during a JPEG write.
 */
typedef struct {
	VipsImage *in;
	struct jpeg_compress_struct cinfo;
        ErrorManager eman;
	JSAMPROW *row_pointer;
	char *profile_bytes;
	size_t profile_length;
	VipsImage *inverted;
} Write;

static void
write_destroy( Write *write )
{
	jpeg_destroy_compress( &write->cinfo );
	VIPS_FREEF( fclose, write->eman.fp );
	VIPS_FREE( write->row_pointer );
	VIPS_FREE( write->profile_bytes );
	VIPS_UNREF( write->inverted );

	g_free( write );
}

static Write *
write_new( VipsImage *in )
{
	Write *write;

	if( !(write = g_new0( Write, 1 )) )
		return( NULL );

	write->in = in;
	write->row_pointer = NULL;
        write->cinfo.err = jpeg_std_error( &write->eman.pub );
	write->eman.pub.error_exit = vips__new_error_exit;
	write->eman.pub.output_message = vips__new_output_message;
	write->eman.fp = NULL;
	write->profile_bytes = NULL;
	write->profile_length = 0;
	write->inverted = NULL;

        return( write );
}

#ifdef HAVE_EXIF
static void
vips_exif_set_int( ExifData *ed, 
	ExifEntry *entry, unsigned long component, void *data )
{
	int value = *((int *) data);

	ExifByteOrder bo;
	size_t sizeof_component;
	size_t offset = component;

	if( entry->components <= component ) {
		VIPS_DEBUG_MSG( "vips_exif_set_int: too few components\n" );
		return;
	}

	/* Wait until after the component check to make sure we cant get /0.
	 */
	bo = exif_data_get_byte_order( ed );
	sizeof_component = entry->size / entry->components;
	offset = component * sizeof_component;

	VIPS_DEBUG_MSG( "vips_exif_set_int: %s = %d\n",
		exif_tag_get_name( entry->tag ), value );

	if( entry->format == EXIF_FORMAT_SHORT ) 
		exif_set_short( entry->data + offset, bo, value );
	else if( entry->format == EXIF_FORMAT_SSHORT ) 
		exif_set_sshort( entry->data + offset, bo, value );
	else if( entry->format == EXIF_FORMAT_LONG ) 
		exif_set_long( entry->data + offset, bo, value );
	else if( entry->format == EXIF_FORMAT_SLONG ) 
		exif_set_slong( entry->data + offset, bo, value );
}

static void
vips_exif_double_to_rational( double value, ExifRational *rv )
{
	/* We will usually set factors of 10, so use 1000 as the denominator
	 * and it'll probably be OK.
	 */
	rv->numerator = value * 1000;
	rv->denominator = 1000;
}

static void
vips_exif_double_to_srational( double value, ExifSRational *srv )
{
	/* We will usually set factors of 10, so use 1000 as the denominator
	 * and it'll probably be OK.
	 */
	srv->numerator = value * 1000;
	srv->denominator = 1000;
}

/* Parse a char* into an ExifRational. We allow floats as well.
 */
static void
vips_exif_parse_rational( const char *str, ExifRational *rv )
{
	if( sscanf( str, " %u / %u ", &rv->numerator, &rv->denominator ) == 2 )
		return;
	vips_exif_double_to_rational( g_ascii_strtod( str, NULL ), rv );
}

/* Parse a char* into an ExifSRational. We allow floats as well.
 */
static void
vips_exif_parse_srational( const char *str, ExifSRational *srv )
{
	if( sscanf( str, " %d / %d ", 
		&srv->numerator, &srv->denominator ) == 2 )
		return;
	vips_exif_double_to_srational( g_ascii_strtod( str, NULL ), srv );
}

/* Does both signed and unsigned rationals from a char*.
 */
static void
vips_exif_set_rational( ExifData *ed, 
	ExifEntry *entry, unsigned long component, void *data )
{
	char *value = (char *) data;

	ExifByteOrder bo;
	size_t sizeof_component;
	size_t offset;

	if( entry->components <= component ) {
		VIPS_DEBUG_MSG( "vips_exif_set_rational: "
			"too few components\n" );
		return;
	}

	/* Wait until after the component check to make sure we cant get /0.
	 */
	bo = exif_data_get_byte_order( ed );
	sizeof_component = entry->size / entry->components;
	offset = component * sizeof_component;

	VIPS_DEBUG_MSG( "vips_exif_set_rational: %s = \"%s\"\n",
		exif_tag_get_name( entry->tag ), value );

	if( entry->format == EXIF_FORMAT_RATIONAL ) {
		ExifRational rv;

		vips_exif_parse_rational( value, &rv ); 

		VIPS_DEBUG_MSG( "vips_exif_set_rational: %u / %u\n", 
			rv.numerator, 
			rv.denominator ); 

		exif_set_rational( entry->data + offset, bo, rv );
	}
	else if( entry->format == EXIF_FORMAT_SRATIONAL ) {
		ExifSRational srv;

		vips_exif_parse_srational( value, &srv ); 

		VIPS_DEBUG_MSG( "vips_exif_set_rational: %d / %d\n", 
			srv.numerator, srv.denominator ); 

		exif_set_srational( entry->data + offset, bo, srv );
	}
}

/* Does both signed and unsigned rationals from a double*.
 *
 * Don't change the exit entry if the value currently there is a good
 * approximation of the double we are trying to set.
 */
static void
vips_exif_set_double( ExifData *ed, 
	ExifEntry *entry, unsigned long component, void *data )
{
	double value = *((double *) data);

	ExifByteOrder bo;
	size_t sizeof_component;
	size_t offset;
	double old_value;

	if( entry->components <= component ) {
		VIPS_DEBUG_MSG( "vips_exif_set_double: "
			"too few components\n" );
		return;
	}

	/* Wait until after the component check to make sure we cant get /0.
	 */
	bo = exif_data_get_byte_order( ed );
	sizeof_component = entry->size / entry->components;
	offset = component * sizeof_component;

	VIPS_DEBUG_MSG( "vips_exif_set_double: %s = %g\n",
		exif_tag_get_name( entry->tag ), value );

	if( entry->format == EXIF_FORMAT_RATIONAL ) {
		ExifRational rv;

		rv = exif_get_rational( entry->data + offset, bo );
		old_value = (double) rv.numerator / rv.denominator;
		if( VIPS_FABS( old_value - value ) > 0.0001 ) {
			vips_exif_double_to_rational( value, &rv ); 

			VIPS_DEBUG_MSG( "vips_exif_set_double: %u / %u\n", 
				rv.numerator, 
				rv.denominator ); 

			exif_set_rational( entry->data + offset, bo, rv );
		}
	}
	else if( entry->format == EXIF_FORMAT_SRATIONAL ) {
		ExifSRational srv;

		srv = exif_get_srational( entry->data + offset, bo );
		old_value = (double) srv.numerator / srv.denominator;
		if( VIPS_FABS( old_value - value ) > 0.0001 ) {
			vips_exif_double_to_srational( value, &srv ); 

			VIPS_DEBUG_MSG( "vips_exif_set_double: %d / %d\n", 
				srv.numerator, srv.denominator ); 

			exif_set_srational( entry->data + offset, bo, srv );
		}
	}
}

typedef void (*write_fn)( ExifData *ed, 
	ExifEntry *entry, unsigned long component, void *data );

/* Write a tag. Update what's there, or make a new one.
 */
static void
write_tag( ExifData *ed, int ifd, ExifTag tag, write_fn fn, void *data )
{
	ExifEntry *entry;

	if( (entry = exif_content_get_entry( ed->ifd[ifd], tag )) ) {
		fn( ed, entry, 0, data );
	}
	else {
		entry = exif_entry_new();

		/* tag must be set before calling exif_content_add_entry.
		 */
		entry->tag = tag; 

		exif_content_add_entry( ed->ifd[ifd], entry );
		exif_entry_initialize( entry, tag );
		exif_entry_unref( entry );

		fn( ed, entry, 0, data );
	}
}

/* This is different, we set the xres/yres from the vips header rather than
 * from the exif tags on the image metadata.
 *
 * This is also called from the jpg reader to fix up bad exif resoltion.
 */
int
vips__set_exif_resolution( ExifData *ed, VipsImage *im )
{
	double xres, yres;
	const char *p;
	int unit;

	VIPS_DEBUG_MSG( "vips__set_exif_resolution: vips res of %g, %g\n",
		im->Xres, im->Yres );

	/* Default to inches, more progs support it.
	 */
	unit = 2;
	if( vips_image_get_typeof( im, VIPS_META_RESOLUTION_UNIT ) &&
		!vips_image_get_string( im, VIPS_META_RESOLUTION_UNIT, &p ) ) {
		if( vips_isprefix( "cm", p ) ) 
			unit = 3;
		else if( vips_isprefix( "none", p ) ) 
			unit = 1;
	}

	switch( unit ) {
	case 1:
		xres = im->Xres;
		yres = im->Yres;
		break;

	case 2:
		xres = im->Xres * 25.4;
		yres = im->Yres * 25.4;
		break;

	case 3:
		xres = im->Xres * 10.0;
		yres = im->Yres * 10.0;
		break;

	default:
		vips_warn( "VipsJpeg", 
			"%s", _( "unknown EXIF resolution unit" ) );
		return( 0 );
	}

	/* Main image xres/yres/unit are in ifd0. ifd1 has the thumbnail
	 * xres/yres/unit.
	 */
	write_tag( ed, 0, EXIF_TAG_X_RESOLUTION, 
		vips_exif_set_double, (void *) &xres );
	write_tag( ed, 0, EXIF_TAG_Y_RESOLUTION, 
		vips_exif_set_double, (void *) &yres );
	write_tag( ed, 0, EXIF_TAG_RESOLUTION_UNIT, 
		vips_exif_set_int, (void *) &unit );

	return( 0 );
}

/* Exif also tracks image dimensions. 
 */
static int
set_exif_dimensions( ExifData *ed, VipsImage *im )
{
	VIPS_DEBUG_MSG( "set_exif_dimensions: vips size of %d, %d\n",
		im->Xsize, im->Ysize );

	write_tag( ed, 2, EXIF_TAG_PIXEL_X_DIMENSION, 
		vips_exif_set_int, (void *) &im->Xsize );
	write_tag( ed, 2, EXIF_TAG_PIXEL_Y_DIMENSION, 
		vips_exif_set_int, (void *) &im->Ysize );

	return( 0 );
}

/* And orientation. 
 */
static int
set_exif_orientation( ExifData *ed, VipsImage *im )
{
	int orientation;

	/* We set the tag, even if it's been deleted, since it's a required
	 * field.
	 */
	if( !vips_image_get_typeof( im, VIPS_META_ORIENTATION ) ||
		vips_image_get_int( im, VIPS_META_ORIENTATION, &orientation ) ) 
		orientation = 1;

	VIPS_DEBUG_MSG( "set_exif_orientation: %d\n", orientation );

	write_tag( ed, 0, EXIF_TAG_ORIENTATION, 
		vips_exif_set_int, (void *) &orientation );

	return( 0 );
}

/* See also vips_exif_to_s() ... keep in sync.
 */
static void
vips_exif_from_s( ExifData *ed, ExifEntry *entry, const char *value )
{
	unsigned long i;
	const char *p;

	if( entry->format != EXIF_FORMAT_SHORT &&
		entry->format != EXIF_FORMAT_SSHORT &&
		entry->format != EXIF_FORMAT_LONG &&
		entry->format != EXIF_FORMAT_SLONG &&
		entry->format != EXIF_FORMAT_RATIONAL &&
		entry->format != EXIF_FORMAT_SRATIONAL )
		return;
	if( entry->components >= 10 )
		return;

	/* Skip any leading spaces.
	 */
	p = value;
	while( *p == ' ' )
		p += 1;

	for( i = 0; i < entry->components; i++ ) {
		if( entry->format == EXIF_FORMAT_SHORT || 
			entry->format == EXIF_FORMAT_SSHORT || 
			entry->format == EXIF_FORMAT_LONG || 
			entry->format == EXIF_FORMAT_SLONG ) {
			int value = atof( p );

			vips_exif_set_int( ed, entry, i, &value );
		}
		else if( entry->format == EXIF_FORMAT_RATIONAL || 
			entry->format == EXIF_FORMAT_SRATIONAL ) 
			vips_exif_set_rational( ed, entry, i, (void *) p );

		/* Skip to the next set of spaces, then to the beginning of
		 * the next item.
		 */
		while( *p && *p != ' ' )
			p += 1;
		while( *p == ' ' )
			p += 1;
		if( !*p )
			break;
	}
}

static void 
vips_exif_set_entry( ExifData *ed, ExifEntry *entry, 
	unsigned long component, void *data )
{
	const char *string = (const char *) data; 

	vips_exif_from_s( ed, entry, string ); 
}

static void *
vips_exif_image_field( VipsImage *image, 
	const char *field, GValue *value, void *data )
{
	ExifData *ed = (ExifData *) data;

	const char *string;
	int ifd;
	const char *p;
	ExifTag tag;

	if( !vips_isprefix( "exif-ifd", field ) ) 
		return( NULL );

	/* value must be a string.
	 */
	if( vips_image_get_string( image, field, &string ) ) {
		vips_warn( "VipsJpeg", _( "bad exif meta \"%s\"" ), field );
		return( NULL ); 
	}

	p = field + strlen( "exif-ifd" );
	ifd = atoi( p ); 

	for( ; isdigit( *p ); p++ )
		;
	if( *p != '-' ) {
		vips_warn( "VipsJpeg", _( "bad exif meta \"%s\"" ), field );
		return( NULL ); 
	}

	if( !(tag = exif_tag_from_name( p + 1 )) ) {
		vips_warn( "VipsJpeg", _( "bad exif meta \"%s\"" ), field );
		return( NULL ); 
	}

	write_tag( ed, ifd, tag, vips_exif_set_entry, (void *) string );

	return( NULL ); 
}

typedef struct _VipsExif {
	VipsImage *image;
	ExifData *ed;
	ExifContent *content;
	GSList *to_remove;
} VipsExif;

static void
vips_exif_exif_entry( ExifEntry *entry, VipsExif *ve )
{
	const char *tag_name;
	char vips_name_txt[256];
	VipsBuf vips_name = VIPS_BUF_STATIC( vips_name_txt );

	if( !(tag_name = exif_tag_get_name( entry->tag )) )
		return;

	vips_buf_appendf( &vips_name, "exif-ifd%d-%s", 
		exif_entry_get_ifd( entry ), tag_name );

	/* Does this field exist on the image? If not, schedule it for
	 * removal.
	 */
	if( !vips_image_get_typeof( ve->image, vips_buf_all( &vips_name ) ) ) 
		ve->to_remove = g_slist_prepend( ve->to_remove, entry );

	/* Orientation is really set from the vips
	 * VIPS_META_ORIENTATION tag. If that's been deleted, we must delete
	 * any matching EXIF tags too.
	 */
	if( strcmp( tag_name, "Orientation" ) == 0 &&
		vips_image_get_typeof( ve->image, VIPS_META_ORIENTATION ) )
		ve->to_remove = g_slist_prepend( ve->to_remove, entry );
}

static void *
vips_exif_exif_remove( ExifEntry *entry, VipsExif *ve )
{
#ifdef DEBUG
{
	const char *tag_name;
	char vips_name_txt[256];
	VipsBuf vips_name = VIPS_BUF_STATIC( vips_name_txt );

	tag_name = exif_tag_get_name( entry->tag );
	vips_buf_appendf( &vips_name, "exif-ifd%d-%s", 
		exif_entry_get_ifd( entry ), tag_name );

	printf( "vips_exif_exif_remove: %s\n", vips_buf_all( &vips_name ) );
}
#endif /*DEBUG*/

	exif_content_remove_entry( ve->content, entry );

	return( NULL );
}

static void
vips_exif_exif_content( ExifContent *content, VipsExif *ve )
{
	ve->content = content;
	ve->to_remove = NULL;
        exif_content_foreach_entry( content, 
		(ExifContentForeachEntryFunc) vips_exif_exif_entry, ve );
	vips_slist_map2( ve->to_remove,
		(VipsSListMap2Fn) vips_exif_exif_remove, ve, NULL );
	VIPS_FREEF( g_slist_free, ve->to_remove );
}

static void
vips_exif_update( ExifData *ed, VipsImage *image )
{
	VipsExif ve;

	VIPS_DEBUG_MSG( "vips_exif_update: \n" );

	/* Walk the image and update any stuff that's been changed in image
	 * metadata.
	 */
	vips_image_map( image, vips_exif_image_field, ed );

	/* Walk the exif and look for any fields which are NOT in image
	 * metadata. They must have been removed ... remove them from exif as
	 * well.
	 */
	ve.image = image;
	ve.ed = ed;
	exif_data_foreach_content( ed, 
		(ExifDataForeachContentFunc) vips_exif_exif_content, &ve );
}

#endif /*HAVE_EXIF*/

static int
write_blob( Write *write, const char *field, int app )
{
	unsigned char *data;
	size_t data_length;

	if( vips_image_get_typeof( write->in, field ) ) {
		if( vips_image_get_blob( write->in, field, 
			(void *) &data, &data_length ) )
			return( -1 );

		/* Single jpeg markers can only hold 64kb, large objects must
		 * be split into multiple markers.
		 *
		 * Unfortunately, how this splitting is done depends on the
		 * data type. For example, ICC and XMP have completely 
		 * different ways of doing this.
		 *
		 * For now, just ignore oversize objects and warn.
		 */
		if( data_length > 65530 ) 
			vips_warn( "VipsJpeg", _( "field \"%s\" is too large "
				"for a single JPEG marker, ignoring" ), 
				field );
		else {
#ifdef DEBUG
			printf( "write_blob: attaching %zd bytes of %s\n", 
				data_length, field );
#endif /*DEBUG*/

			jpeg_write_marker( &write->cinfo, app, 
				data, data_length ); } }

	return( 0 );
}

static int
write_exif( Write *write )
{
#ifdef HAVE_EXIF
	unsigned char *data;
	size_t data_length;
	unsigned int idl;
	ExifData *ed;

	/* Either parse from the embedded EXIF, or if there's none, make
	 * some fresh EXIF we can write the resolution to.
	 */
	if( vips_image_get_typeof( write->in, VIPS_META_EXIF_NAME ) ) {
		if( vips_image_get_blob( write->in, VIPS_META_EXIF_NAME, 
			(void *) &data, &data_length ) )
			return( -1 );

		if( !(ed = exif_data_new_from_data( data, data_length )) )
			return( -1 );
	}
	else  {
		ed = exif_data_new();

		exif_data_set_option( ed, 
			EXIF_DATA_OPTION_FOLLOW_SPECIFICATION );
		exif_data_set_data_type( ed, EXIF_DATA_TYPE_COMPRESSED );
		exif_data_set_byte_order( ed, EXIF_BYTE_ORDER_INTEL );
	
		/* Create the mandatory EXIF fields with default data.
		 */
		exif_data_fix( ed );
	}

	/* Update EXIF tags from the image metadata.
	 */
	vips_exif_update( ed, write->in );

	/* Update EXIF resolution from the vips image header.
	 */
	if( vips__set_exif_resolution( ed, write->in ) ) {
		exif_data_free( ed );
		return( -1 );
	}

	/* Update EXIF image dimensions from the vips image header.
	 */
	if( set_exif_dimensions( ed, write->in ) ) {
		exif_data_free( ed );
		return( -1 );
	}

	/* Update EXIF orientation from the vips image header.
	 */
	if( set_exif_orientation( ed, write->in ) ) {
		exif_data_free( ed );
		return( -1 );
	}

	/* Reserialise and write. exif_data_save_data() returns an int for some
	 * reason.
	 */
	exif_data_save_data( ed, &data, &idl );
	if( !idl ) {
		vips_error( "VipsJpeg", "%s", _( "error saving EXIF" ) );
		exif_data_free( ed );
		return( -1 );
	}
	data_length = idl;

#ifdef DEBUG
	printf( "write_exif: attaching %zd bytes of EXIF\n", data_length  );
#endif /*DEBUG*/

	exif_data_free( ed );
	jpeg_write_marker( &write->cinfo, JPEG_APP0 + 1, data, data_length );
	free( data );
#else /*!HAVE_EXIF*/
	/* No libexif ... just copy the embedded EXIF over.
	 */
	if( write_blob( write, VIPS_META_EXIF_NAME, JPEG_APP0 + 1 ) )
		return( -1 );
#endif /*!HAVE_EXIF*/

	return( 0 );
}

/* ICC writer from lcms, slight tweaks.
 */

#define ICC_MARKER  (JPEG_APP0 + 2)     /* JPEG marker code for ICC */
#define ICC_OVERHEAD_LEN  14            /* size of non-profile data in APP2 */
#define MAX_BYTES_IN_MARKER  65533      /* maximum data len of a JPEG marker */
#define MAX_DATA_BYTES_IN_MARKER  (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)

/*
 * This routine writes the given ICC profile data into a JPEG file.
 * It *must* be called AFTER calling jpeg_start_compress() and BEFORE
 * the first call to jpeg_write_scanlines().
 * (This ordering ensures that the APP2 marker(s) will appear after the
 * SOI and JFIF or Adobe markers, but before all else.)
 */

static void
write_profile_data (j_compress_ptr cinfo,
                   const JOCTET *icc_data_ptr,
                   unsigned int icc_data_len)
{
  unsigned int num_markers;     /* total number of markers we'll write */
  int cur_marker = 1;           /* per spec, counting starts at 1 */
  unsigned int length;          /* number of bytes to write in this marker */

  /* rounding up will fail for length == 0 */
  g_assert( icc_data_len > 0 );

  /* Calculate the number of markers we'll need, rounding up of course */
  num_markers = (icc_data_len + MAX_DATA_BYTES_IN_MARKER - 1) / 
	  MAX_DATA_BYTES_IN_MARKER;

  while (icc_data_len > 0) {
    /* length of profile to put in this marker */
    length = icc_data_len;
    if (length > MAX_DATA_BYTES_IN_MARKER)
      length = MAX_DATA_BYTES_IN_MARKER;
    icc_data_len -= length;

    /* Write the JPEG marker header (APP2 code and marker length) */
    jpeg_write_m_header(cinfo, ICC_MARKER,
                        (unsigned int) (length + ICC_OVERHEAD_LEN));

    /* Write the marker identifying string "ICC_PROFILE" (null-terminated).
     * We code it in this less-than-transparent way so that the code works
     * even if the local character set is not ASCII.
     */
    jpeg_write_m_byte(cinfo, 0x49);
    jpeg_write_m_byte(cinfo, 0x43);
    jpeg_write_m_byte(cinfo, 0x43);
    jpeg_write_m_byte(cinfo, 0x5F);
    jpeg_write_m_byte(cinfo, 0x50);
    jpeg_write_m_byte(cinfo, 0x52);
    jpeg_write_m_byte(cinfo, 0x4F);
    jpeg_write_m_byte(cinfo, 0x46);
    jpeg_write_m_byte(cinfo, 0x49);
    jpeg_write_m_byte(cinfo, 0x4C);
    jpeg_write_m_byte(cinfo, 0x45);
    jpeg_write_m_byte(cinfo, 0x0);

    /* Add the sequencing info */
    jpeg_write_m_byte(cinfo, cur_marker);
    jpeg_write_m_byte(cinfo, (int) num_markers);

    /* Add the profile data */
    while (length--) {
      jpeg_write_m_byte(cinfo, *icc_data_ptr);
      icc_data_ptr++;
    }
    cur_marker++;
  }
}

/* Write an ICC Profile from a file into the JPEG stream.
 */
static int
write_profile_file( Write *write, const char *profile )
{
	if( !(write->profile_bytes = 
		vips__file_read_name( profile, VIPS_ICC_DIR, 
		&write->profile_length )) ) 
		return( -1 );
	write_profile_data( &write->cinfo, 
		(JOCTET *) write->profile_bytes, write->profile_length );

#ifdef DEBUG
	printf( "write_profile_file: attached profile \"%s\"\n", profile );
#endif /*DEBUG*/

	return( 0 );
}

static int
write_profile_meta( Write *write )
{
	void *data;
	size_t data_length;

	if( vips_image_get_blob( write->in, VIPS_META_ICC_NAME, 
		&data, &data_length ) )
		return( -1 );

	write_profile_data( &write->cinfo, data, data_length );

#ifdef DEBUG
	printf( "write_profile_meta: attached %zd byte profile from header\n",
		data_length );
#endif /*DEBUG*/

	return( 0 );
}

static int
write_jpeg_block( VipsRegion *region, VipsRect *area, void *a )
{
	Write *write = (Write *) a;
	int i;

	for( i = 0; i < area->height; i++ )
		write->row_pointer[i] = (JSAMPROW) 
			VIPS_REGION_ADDR( region, 0, area->top + i );

	/* Catch any longjmp()s from jpeg_write_scanlines() here.
	 */
	if( setjmp( write->eman.jmp ) ) 
		return( -1 );

	jpeg_write_scanlines( &write->cinfo, write->row_pointer, area->height );

	return( 0 );
}

/* Write a VIPS image to a JPEG compress struct.
 */
static int
write_vips( Write *write, int qfac, const char *profile, 
	gboolean optimize_coding, gboolean progressive, gboolean strip, 
	gboolean no_subsample, gboolean trellis_quant,
	gboolean overshoot_deringing, gboolean optimize_scans, int quant_table )
{
	VipsImage *in;
	J_COLOR_SPACE space;

	/* The image we'll be writing ... can change, see CMYK.
	 */
	in = write->in;

	/* Should have been converted for save.
	 */
        g_assert( in->BandFmt == VIPS_FORMAT_UCHAR );
	g_assert( in->Coding == VIPS_CODING_NONE );
        g_assert( in->Bands == 1 || 
		in->Bands == 3 || 
		in->Bands == 4 );

        /* Check input image.
         */
	if( vips_image_pio_input( in ) )
		return( -1 );

	/* Set compression parameters.
	 */
        write->cinfo.image_width = in->Xsize;
        write->cinfo.image_height = in->Ysize;
	write->cinfo.input_components = in->Bands;
	if( in->Bands == 4 && 
		in->Type == VIPS_INTERPRETATION_CMYK ) {
		space = JCS_CMYK;
		/* IJG always sets an Adobe marker, so we should invert CMYK.
		 */
		if( vips_invert( in, &write->inverted, NULL ) ) 
			return( -1 );
		in = write->inverted;
	}
	else if( in->Bands == 3 )
		space = JCS_RGB;
	else if( in->Bands == 1 )
		space = JCS_GRAYSCALE;
	else 
		/* Use luminance compression for all channels.
		 */
		space = JCS_UNKNOWN;
	write->cinfo.in_color_space = space; 

	/* Build VIPS output stuff now we know the image we'll be writing.
	 */
	if( !(write->row_pointer = VIPS_ARRAY( NULL, in->Ysize, JSAMPROW )) )
		return( -1 );

#ifdef HAVE_JPEG_EXT_PARAMS
	/* Reset compression profile to libjpeg defaults
	 */
	if( jpeg_c_int_param_supported( &write->cinfo, JINT_COMPRESS_PROFILE ) )
		jpeg_c_set_int_param( &write->cinfo, 
			JINT_COMPRESS_PROFILE, JCP_FASTEST );
#endif

	/* Reset to default.
	 */
        jpeg_set_defaults( &write->cinfo );

 	/* Compute optimal Huffman coding tables.
	 */
	write->cinfo.optimize_coding = optimize_coding;

#ifdef HAVE_JPEG_EXT_PARAMS
	/* Apply trellis quantisation to each 8x8 block. Implies 
	 * "optimize_coding".
	 */
	if( trellis_quant ) {
		if( jpeg_c_bool_param_supported( &write->cinfo, 
			JBOOLEAN_TRELLIS_QUANT ) ) {
			jpeg_c_set_bool_param( &write->cinfo,
				JBOOLEAN_TRELLIS_QUANT, TRUE );
			write->cinfo.optimize_coding = TRUE;
		}
		else 
			vips_warn( "vips2jpeg", 
				"%s", _( "trellis_quant unsupported" ) );
	}

	/* Apply overshooting to samples with extreme values e.g. 0 & 255 
	 * for 8-bit.
	 */
	if( overshoot_deringing ) {
		if( jpeg_c_bool_param_supported( &write->cinfo, 
			JBOOLEAN_OVERSHOOT_DERINGING ) ) 
			jpeg_c_set_bool_param( &write->cinfo,
				JBOOLEAN_OVERSHOOT_DERINGING, TRUE );
		else 
			vips_warn( "vips2jpeg", 
				"%s", _( "overshoot_deringing unsupported" ) );
	}
	/* Split the spectrum of DCT coefficients into separate scans.
	 * Requires progressive output. Must be set before 
	 * jpeg_simple_progression.
	 */
	if( optimize_scans ) {
		if( progressive ) {
			if( jpeg_c_bool_param_supported( &write->cinfo, 
				JBOOLEAN_OPTIMIZE_SCANS ) ) 
				jpeg_c_set_bool_param( &write->cinfo, 
					JBOOLEAN_OPTIMIZE_SCANS, TRUE );
			else 
				vips_warn( "vips2jpeg", 
					"%s", _( "Ignoring optimize_scans" ) );
		}
		else 
			vips_warn( "vips2jpeg", "%s",
				_( "Ignoring optimize_scans for baseline" ) );
	}

	/* Use predefined quantization table.
	 */
	if( quant_table > 0 ) {
		if( jpeg_c_int_param_supported( &write->cinfo,
			JINT_BASE_QUANT_TBL_IDX ) )
			jpeg_c_set_int_param( &write->cinfo,
				JINT_BASE_QUANT_TBL_IDX, quant_table );
		else
			vips_warn( "vips2jpeg",
				"%s", _( "Setting quant_table unsupported" ) );
	}
#else
	/* Using jpeglib.h without extension parameters, warn of ignored 
	 * options.
	 */
	if( trellis_quant ) 
		vips_warn( "vips2jpeg", "%s", _( "Ignoring trellis_quant" ) );
	if( overshoot_deringing ) 
		vips_warn( "vips2jpeg", 
			"%s", _( "Ignoring overshoot_deringing" ) );
	if( optimize_scans ) 
		vips_warn( "vips2jpeg", "%s", _( "Ignoring optimize_scans" ) );
	if( quant_table > 0 )
		vips_warn( "vips2jpeg", "%s", _( "Ignoring quant_table" ) );
#endif

	/* Set compression quality. Must be called after setting params above.
	 */
        jpeg_set_quality( &write->cinfo, qfac, TRUE );

	/* Enable progressive write.
	 */
	if( progressive ) 
		jpeg_simple_progression( &write->cinfo ); 

	/* Turn off chroma subsampling. Follow IM and do it automatically for
	 * high Q. 
	 */
	if( no_subsample ||
		qfac > 90 ) { 
		int i;

		for( i = 0; i < in->Bands; i++ ) { 
			write->cinfo.comp_info[i].h_samp_factor = 1;
			write->cinfo.comp_info[i].v_samp_factor = 1;
		}
	}

	/* Don't write the APP0 JFIF headers if we are stripping.
	 */
	if( strip ) 
		write->cinfo.write_JFIF_header = FALSE;

	/* Build compress tables.
	 */
	jpeg_start_compress( &write->cinfo, TRUE );

	/* Write any APP markers we need.
	 */
	if( !strip ) { 
		if( write_exif( write ) ||
			write_blob( write, 
				VIPS_META_XMP_NAME, JPEG_APP0 + 1 ) ||
			write_blob( write, 
				VIPS_META_IPCT_NAME, JPEG_APP0 + 13 ) )
			return( -1 );

		/* A profile supplied as an argument overrides an embedded 
		 * profile. "none" means don't attach a profile.
		 */
		if( profile && 
			strcmp( profile, "none" ) != 0 &&
			write_profile_file( write, profile ) )
			return( -1 );
		if( !profile && 
			vips_image_get_typeof( in, VIPS_META_ICC_NAME ) && 
			write_profile_meta( write ) )
			return( -1 );
	}

	/* Write data. Note that the write function grabs the longjmp()!
	 */
	if( vips_sink_disc( in, write_jpeg_block, write ) )
		return( -1 );

	/* We have to reinstate the setjmp() before we jpeg_finish_compress().
	 */
	if( setjmp( write->eman.jmp ) ) 
		return( -1 );

	jpeg_finish_compress( &write->cinfo );

	return( 0 );
}

/* Write an image to a jpeg file.
 */
int
vips__jpeg_write_file( VipsImage *in, 
	const char *filename, int Q, const char *profile, 
	gboolean optimize_coding, gboolean progressive, gboolean strip, 
	gboolean no_subsample, gboolean trellis_quant,
	gboolean overshoot_deringing, gboolean optimize_scans, int quant_table )
{
	Write *write;

	if( !(write = write_new( in )) )
		return( -1 );

	if( setjmp( write->eman.jmp ) ) {
		/* Here for longjmp() from new_error_exit().
		 */
		write_destroy( write );

		return( -1 );
	}

	/* Can't do this in write_new(), has to be after we've made the
	 * setjmp().
	 */
        jpeg_create_compress( &write->cinfo );

	/* Make output.
	 */
        if( !(write->eman.fp = vips__file_open_write( filename, FALSE )) ) {
		write_destroy( write );
                return( -1 );
        }
        jpeg_stdio_dest( &write->cinfo, write->eman.fp );

	/* Convert!
	 */
	if( write_vips( write, 
		Q, profile, optimize_coding, progressive, strip, no_subsample,
		trellis_quant, overshoot_deringing, optimize_scans, 
		quant_table ) ) {
		write_destroy( write );
		return( -1 );
	}
	write_destroy( write );

	return( 0 );
}

/* We can't predict how large the output buffer we need is, because we might
 * need space for ICC profiles and stuff. So we write to a linked list of mem
 * buffers and add a new one as they fill.
 */

#define BUFFER_SIZE (10000)

/* A buffer.
 */
typedef struct _Block {
	j_compress_ptr cinfo;

	struct _Block *first;
	struct _Block *next;

	JOCTET *data;		/* Allocated area */
	size_t size;		/* Max size */
	size_t used;		/* How much has been used */
} Block;

static Block *
block_new( j_compress_ptr cinfo )
{
	Block *block;

	block = (Block *) (*cinfo->mem->alloc_large) 
		( (j_common_ptr) cinfo, JPOOL_IMAGE, sizeof( Block ) );

	block->cinfo = cinfo;
	block->first = block;
	block->next = NULL;
	block->data = (JOCTET *) (*cinfo->mem->alloc_large) 
		( (j_common_ptr) cinfo, JPOOL_IMAGE, BUFFER_SIZE );
	block->size = BUFFER_SIZE;
	block->used = 0;

	return( block );
}

static Block *
block_last( Block *block )
{
	while( block->next )
		block = block->next;

	return( block );
}

static Block *
block_append( Block *block )
{
	Block *new;

	g_assert( block );

	new = block_new( block->cinfo );
	new->first = block->first;
	block_last( block )->next = new;

	return( new );
}

static size_t
block_length( Block *block )
{
	size_t len;

	len = 0;
	for( block = block->first; block; block = block->next )
		len += block->used;

	return( len );
}

static void
block_copy( Block *block, void *dest )
{
	JOCTET *p;
	
	p = dest;
	for( block = block->first; block; block = block->next ) {
		memcpy( p, block->data, block->used );
		p += block->used;
	}
}

#ifdef DEBUG
static void
block_print( Block *block )
{
	int i;

	printf( "total length = %zd\n", block_length( block ) );
	printf( "set of blocks:\n" );

	i = 0;
	for( block = block->first; block; block = block->next ) {
		printf( "%d) %p, first = %p, next = %p"
			"\t data = %p, size = %zd, used = %zd\n", 
			i, block, block->first, block->next,
			block->data, block->size, block->used );
		i += 1;
	}
}
#endif /*DEBUG*/

/* Just like the above, but we write to a memory buffer.
 *
 * A memory buffer for the compressed image.
 */
typedef struct {
	/* Public jpeg fields.
	 */
	struct jpeg_destination_mgr pub;

	/* Private stuff during write.
	 */

	/* Build the output area here in chunks.
	 */
	Block *block;

	/* Copy the compressed area here.
	 */
	void **obuf;		/* Allocated buffer, and size */
	size_t *olen;
} OutputBuffer;

/* Init dest method.
 */
METHODDEF(void)
init_destination( j_compress_ptr cinfo )
{
	OutputBuffer *buf = (OutputBuffer *) cinfo->dest;

	/* Allocate relative to the image we are writing .. freed when we junk
	 * this output.
	 */
	buf->block = block_new( cinfo );

	/* Set buf pointers for library.
	 */
	buf->pub.next_output_byte = buf->block->data;
	buf->pub.free_in_buffer = buf->block->size;
}

/* Buffer full method ... allocate a new output block.
 */
METHODDEF(boolean)
empty_output_buffer( j_compress_ptr cinfo )
{
	OutputBuffer *buf = (OutputBuffer *) cinfo->dest;

	/* Record how many bytes we used. empty_output_buffer() is always
	 * called when the buffer is exactly full.
	 */
	buf->block->used = buf->block->size;

	/* New block and reset.
	 */
	buf->block = block_append( buf->block );
	buf->pub.next_output_byte = buf->block->data;
	buf->pub.free_in_buffer = buf->block->size;

	/* TRUE means we've made some more space.
	 */
	return( 1 );
}

/* Cleanup. Copy the set of blocks out as a big lump.
 */
METHODDEF(void)
term_destination( j_compress_ptr cinfo )
{
        OutputBuffer *buf = (OutputBuffer *) cinfo->dest;

	size_t len;
	void *obuf;

	/* Record the number of bytes we wrote in the final buffer.
	 * pub.free_in_buffer is valid here.
	 */
	buf->block->used = buf->block->size - buf->pub.free_in_buffer;

#ifdef DEBUG
	block_print( buf->block );
#endif /*DEBUG*/

	/* ... and we can count up our buffers now.
	 */
	len = block_length( buf->block );

	/* Allocate and copy to the output area.
	 */
	if( !(obuf = vips_malloc( NULL, len )) )
		ERREXIT( cinfo, JERR_FILE_WRITE );
	else {
		/* coverity doesn't know ERREXIT() does not return, so put
		 * this in an else.
		 */
		*(buf->obuf) = obuf;
		*(buf->olen) = len;

		block_copy( buf->block, obuf );
	}
}

/* Set dest to one of our objects.
 */
static void
buf_dest( j_compress_ptr cinfo, void **obuf, size_t *olen )
{
	OutputBuffer *buf;

	/* The destination object is made permanent so that multiple JPEG 
	 * images can be written to the same file without re-executing 
	 * jpeg_stdio_dest. This makes it dangerous to use this manager and 
	 * a different destination manager serially with the same JPEG object,
	 * because their private object sizes may be different.  
	 *
	 * Caveat programmer.
	 */
	if( !cinfo->dest ) {    /* first time for this JPEG object? */
		cinfo->dest = (struct jpeg_destination_mgr *)
			(*cinfo->mem->alloc_small) 
				( (j_common_ptr) cinfo, JPOOL_PERMANENT,
				  sizeof( OutputBuffer ) );
	}

	buf = (OutputBuffer *) cinfo->dest;
	buf->pub.init_destination = init_destination;
	buf->pub.empty_output_buffer = empty_output_buffer;
	buf->pub.term_destination = term_destination;

	/* Save output parameters.
	 */
	buf->obuf = obuf;
	buf->olen = olen;
}

int
vips__jpeg_write_buffer( VipsImage *in, 
	void **obuf, size_t *olen, int Q, const char *profile, 
	gboolean optimize_coding, gboolean progressive,
	gboolean strip, gboolean no_subsample, gboolean trellis_quant,
	gboolean overshoot_deringing, gboolean optimize_scans, int quant_table )
{
	Write *write;

	if( !(write = write_new( in )) )
		return( -1 );

	/* Clear output parameters.
	 */
	*obuf = NULL;
	*olen = 0;

	/* Make jpeg compression object.
 	 */
	if( setjmp( write->eman.jmp ) ) {
		/* Here for longjmp() from new_error_exit().
		 */
		write_destroy( write );

		return( -1 );
	}
        jpeg_create_compress( &write->cinfo );

	/* Attach output.
	 */
        buf_dest( &write->cinfo, obuf, olen );

	/* Convert!
	 */
	if( write_vips( write, 
		Q, profile, optimize_coding, progressive, strip, no_subsample,
		trellis_quant, overshoot_deringing, optimize_scans, 
		quant_table ) ) {
		write_destroy( write );

		return( -1 );
	}
	write_destroy( write );

	return( 0 );
}

const char *vips__jpeg_suffs[] = { ".jpg", ".jpeg", ".jpe", NULL };

#endif /*HAVE_JPEG*/