PluginJPEG.cpp | searchcode

/src/FreeImage/Source/FreeImage/PluginJPEG.cpp

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Possible License(s): LGPL-3.0, BSD-3-Clause, CPL-1.0, Unlicense, GPL-2.0, GPL-3.0, LGPL-2.0, MPL-2.0-no-copyleft-exception, BSD-2-Clause, LGPL-2.1

// ==========================================================
// JPEG Loader and writer
// Based on code developed by The Independent JPEG Group
//
// Design and implementation by
// - Floris van den Berg (flvdberg@wxs.nl)
// - Jan L. Nauta (jln@magentammt.com)
// - Markus Loibl (markus.loibl@epost.de)
// - Karl-Heinz Bussian (khbussian@moss.de)
// - Hervé Drolon (drolon@infonie.fr)
// - Jascha Wetzel (jascha@mainia.de)
// - Mihail Naydenov (mnaydenov@users.sourceforge.net)
//
// This file is part of FreeImage 3
//
// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
// THIS DISCLAIMER.
//
// Use at your own risk!
// ==========================================================

#ifdef _MSC_VER 
#pragma warning (disable : 4786) // identifier was truncated to 'number' characters
#endif

extern "C" {
#define XMD_H
#undef FAR
#include <setjmp.h>

#include "../LibJPEG/jinclude.h"
#include "../LibJPEG/jpeglib.h"
#include "../LibJPEG/jerror.h"
}

#include "FreeImage.h"
#include "Utilities.h"

#include "../Metadata/FreeImageTag.h"


// ==========================================================
// Plugin Interface
// ==========================================================

static int s_format_id;

// ----------------------------------------------------------
//   Constant declarations
// ----------------------------------------------------------

#define INPUT_BUF_SIZE  4096	// choose an efficiently fread'able size 
#define OUTPUT_BUF_SIZE 4096    // choose an efficiently fwrite'able size

#define EXIF_MARKER		(JPEG_APP0+1)	// EXIF marker / Adobe XMP marker
#define ICC_MARKER		(JPEG_APP0+2)	// ICC profile marker
#define IPTC_MARKER		(JPEG_APP0+13)	// IPTC marker / BIM marker 

#define ICC_HEADER_SIZE 14				// size of non-profile data in APP2
#define MAX_BYTES_IN_MARKER 65533L		// maximum data length of a JPEG marker
#define MAX_DATA_BYTES_IN_MARKER 65519L	// maximum data length of a JPEG APP2 marker

#define MAX_JFXX_THUMB_SIZE (MAX_BYTES_IN_MARKER - 5 - 1)

#define JFXX_TYPE_JPEG 	0x10	// JFIF extension marker: JPEG-compressed thumbnail image
#define JFXX_TYPE_8bit 	0x11	// JFIF extension marker: palette thumbnail image
#define JFXX_TYPE_24bit	0x13	// JFIF extension marker: RGB thumbnail image

// ----------------------------------------------------------
//   Typedef declarations
// ----------------------------------------------------------

typedef struct tagErrorManager {
	/// "public" fields
	struct jpeg_error_mgr pub;
	/// for return to caller
	jmp_buf setjmp_buffer;
} ErrorManager;

typedef struct tagSourceManager {
	/// public fields
	struct jpeg_source_mgr pub;
	/// source stream
	fi_handle infile;
	FreeImageIO *m_io;
	/// start of buffer
	JOCTET * buffer;
	/// have we gotten any data yet ?
	boolean start_of_file;
} SourceManager;

typedef struct tagDestinationManager {
	/// public fields
	struct jpeg_destination_mgr pub;
	/// destination stream
	fi_handle outfile;
	FreeImageIO *m_io;
	/// start of buffer
	JOCTET * buffer;
} DestinationManager;

typedef SourceManager*		freeimage_src_ptr;
typedef DestinationManager* freeimage_dst_ptr;
typedef ErrorManager*		freeimage_error_ptr;

// ----------------------------------------------------------
//   Error handling
// ----------------------------------------------------------

/** Fatal errors (print message and exit) */
static inline void
JPEG_EXIT(j_common_ptr cinfo, int code) {
	freeimage_error_ptr error_ptr = (freeimage_error_ptr)cinfo->err;
	error_ptr->pub.msg_code = code;
	error_ptr->pub.error_exit(cinfo);
}

/** Nonfatal errors (we can keep going, but the data is probably corrupt) */
static inline void
JPEG_WARNING(j_common_ptr cinfo, int code) {
	freeimage_error_ptr error_ptr = (freeimage_error_ptr)cinfo->err;
	error_ptr->pub.msg_code = code;
	error_ptr->pub.emit_message(cinfo, -1);
}

/**
	Receives control for a fatal error.  Information sufficient to
	generate the error message has been stored in cinfo->err; call
	output_message to display it.  Control must NOT return to the caller;
	generally this routine will exit() or longjmp() somewhere.
*/
METHODDEF(void)
jpeg_error_exit (j_common_ptr cinfo) {
	freeimage_error_ptr error_ptr = (freeimage_error_ptr)cinfo->err;

	// always display the message
	error_ptr->pub.output_message(cinfo);

	// allow JPEG with unknown markers
	if(error_ptr->pub.msg_code != JERR_UNKNOWN_MARKER) {
	
		// let the memory manager delete any temp files before we die
		jpeg_destroy(cinfo);
		
		// return control to the setjmp point
		longjmp(error_ptr->setjmp_buffer, 1);		
	}
}

/**
	Actual output of any JPEG message.  Note that this method does not know
	how to generate a message, only where to send it.
*/
METHODDEF(void)
jpeg_output_message (j_common_ptr cinfo) {
	char buffer[JMSG_LENGTH_MAX];
	freeimage_error_ptr error_ptr = (freeimage_error_ptr)cinfo->err;

	// create the message
	error_ptr->pub.format_message(cinfo, buffer);
	// send it to user's message proc
	FreeImage_OutputMessageProc(s_format_id, buffer);
}

// ----------------------------------------------------------
//   Destination manager
// ----------------------------------------------------------

/**
	Initialize destination.  This is called by jpeg_start_compress()
	before any data is actually written. It must initialize
	next_output_byte and free_in_buffer. free_in_buffer must be
	initialized to a positive value.
*/
METHODDEF(void)
init_destination (j_compress_ptr cinfo) {
	freeimage_dst_ptr dest = (freeimage_dst_ptr) cinfo->dest;

	dest->buffer = (JOCTET *)
	  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				  OUTPUT_BUF_SIZE * sizeof(JOCTET));

	dest->pub.next_output_byte = dest->buffer;
	dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
}

/**
	This is called whenever the buffer has filled (free_in_buffer
	reaches zero). In typical applications, it should write out the
	*entire* buffer (use the saved start address and buffer length;
	ignore the current state of next_output_byte and free_in_buffer).
	Then reset the pointer & count to the start of the buffer, and
	return TRUE indicating that the buffer has been dumped.
	free_in_buffer must be set to a positive value when TRUE is
	returned.  A FALSE return should only be used when I/O suspension is
	desired.
*/
METHODDEF(boolean)
empty_output_buffer (j_compress_ptr cinfo) {
	freeimage_dst_ptr dest = (freeimage_dst_ptr) cinfo->dest;

	if (dest->m_io->write_proc(dest->buffer, 1, OUTPUT_BUF_SIZE, dest->outfile) != OUTPUT_BUF_SIZE) {
		// let the memory manager delete any temp files before we die
		jpeg_destroy((j_common_ptr)cinfo);

		JPEG_EXIT((j_common_ptr)cinfo, JERR_FILE_WRITE);
	}

	dest->pub.next_output_byte = dest->buffer;
	dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;

	return TRUE;
}

/**
	Terminate destination --- called by jpeg_finish_compress() after all
	data has been written.  In most applications, this must flush any
	data remaining in the buffer.  Use either next_output_byte or
	free_in_buffer to determine how much data is in the buffer.
*/
METHODDEF(void)
term_destination (j_compress_ptr cinfo) {
	freeimage_dst_ptr dest = (freeimage_dst_ptr) cinfo->dest;

	size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;

	// write any data remaining in the buffer

	if (datacount > 0) {
		if (dest->m_io->write_proc(dest->buffer, 1, (unsigned int)datacount, dest->outfile) != datacount) {
			// let the memory manager delete any temp files before we die
			jpeg_destroy((j_common_ptr)cinfo);
			
			JPEG_EXIT((j_common_ptr)cinfo, JERR_FILE_WRITE);
		}
	}
}

// ----------------------------------------------------------
//   Source manager
// ----------------------------------------------------------

/**
	Initialize source.  This is called by jpeg_read_header() before any
	data is actually read. Unlike init_destination(), it may leave
	bytes_in_buffer set to 0 (in which case a fill_input_buffer() call
	will occur immediately).
*/
METHODDEF(void)
init_source (j_decompress_ptr cinfo) {
	freeimage_src_ptr src = (freeimage_src_ptr) cinfo->src;

	/* We reset the empty-input-file flag for each image,
 	 * but we don't clear the input buffer.
	 * This is correct behavior for reading a series of images from one source.
	*/

	src->start_of_file = TRUE;
}

/**
	This is called whenever bytes_in_buffer has reached zero and more
	data is wanted.  In typical applications, it should read fresh data
	into the buffer (ignoring the current state of next_input_byte and
	bytes_in_buffer), reset the pointer & count to the start of the
	buffer, and return TRUE indicating that the buffer has been reloaded.
	It is not necessary to fill the buffer entirely, only to obtain at
	least one more byte.  bytes_in_buffer MUST be set to a positive value
	if TRUE is returned.  A FALSE return should only be used when I/O
	suspension is desired.
*/
METHODDEF(boolean)
fill_input_buffer (j_decompress_ptr cinfo) {
	freeimage_src_ptr src = (freeimage_src_ptr) cinfo->src;

	size_t nbytes = src->m_io->read_proc(src->buffer, 1, INPUT_BUF_SIZE, src->infile);

	if (nbytes <= 0) {
		if (src->start_of_file)	{
			// treat empty input file as fatal error

			// let the memory manager delete any temp files before we die
			jpeg_destroy((j_common_ptr)cinfo);

			JPEG_EXIT((j_common_ptr)cinfo, JERR_INPUT_EMPTY);
		}

		JPEG_WARNING((j_common_ptr)cinfo, JWRN_JPEG_EOF);

		/* Insert a fake EOI marker */

		src->buffer[0] = (JOCTET) 0xFF;
		src->buffer[1] = (JOCTET) JPEG_EOI;

		nbytes = 2;
	}

	src->pub.next_input_byte = src->buffer;
	src->pub.bytes_in_buffer = nbytes;
	src->start_of_file = FALSE;

	return TRUE;
}

/**
	Skip num_bytes worth of data.  The buffer pointer and count should
	be advanced over num_bytes input bytes, refilling the buffer as
	needed. This is used to skip over a potentially large amount of
	uninteresting data (such as an APPn marker). In some applications
	it may be possible to optimize away the reading of the skipped data,
	but it's not clear that being smart is worth much trouble; large
	skips are uncommon.  bytes_in_buffer may be zero on return.
	A zero or negative skip count should be treated as a no-op.
*/
METHODDEF(void)
skip_input_data (j_decompress_ptr cinfo, long num_bytes) {
	freeimage_src_ptr src = (freeimage_src_ptr) cinfo->src;

	/* Just a dumb implementation for now.  Could use fseek() except
     * it doesn't work on pipes.  Not clear that being smart is worth
	 * any trouble anyway --- large skips are infrequent.
	*/

	if (num_bytes > 0) {
		while (num_bytes > (long) src->pub.bytes_in_buffer) {
		  num_bytes -= (long) src->pub.bytes_in_buffer;

		  (void) fill_input_buffer(cinfo);

		  /* note we assume that fill_input_buffer will never return FALSE,
		   * so suspension need not be handled.
		   */
		}

		src->pub.next_input_byte += (size_t) num_bytes;
		src->pub.bytes_in_buffer -= (size_t) num_bytes;
	}
}

/**
	Terminate source --- called by jpeg_finish_decompress
	after all data has been read.  Often a no-op.

	NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
	application must deal with any cleanup that should happen even
	for error exit.
*/
METHODDEF(void)
term_source (j_decompress_ptr cinfo) {
  // no work necessary here
}

// ----------------------------------------------------------
//   Source manager & Destination manager setup
// ----------------------------------------------------------

/**
	Prepare for input from a stdio stream.
	The caller must have already opened the stream, and is responsible
	for closing it after finishing decompression.
*/
GLOBAL(void)
jpeg_freeimage_src (j_decompress_ptr cinfo, fi_handle infile, FreeImageIO *io) {
	freeimage_src_ptr src;

	// allocate memory for the buffer. is released automatically in the end

	if (cinfo->src == NULL) {
		cinfo->src = (struct jpeg_source_mgr *) (*cinfo->mem->alloc_small)
			((j_common_ptr) cinfo, JPOOL_PERMANENT, sizeof(SourceManager));

		src = (freeimage_src_ptr) cinfo->src;

		src->buffer = (JOCTET *) (*cinfo->mem->alloc_small)
			((j_common_ptr) cinfo, JPOOL_PERMANENT, INPUT_BUF_SIZE * sizeof(JOCTET));
	}

	// initialize the jpeg pointer struct with pointers to functions

	src = (freeimage_src_ptr) cinfo->src;
	src->pub.init_source = init_source;
	src->pub.fill_input_buffer = fill_input_buffer;
	src->pub.skip_input_data = skip_input_data;
	src->pub.resync_to_restart = jpeg_resync_to_restart; // use default method 
	src->pub.term_source = term_source;
	src->infile = infile;
	src->m_io = io;
	src->pub.bytes_in_buffer = 0;		// forces fill_input_buffer on first read 
	src->pub.next_input_byte = NULL;	// until buffer loaded 
}

/**
	Prepare for output to a stdio stream.
	The caller must have already opened the stream, and is responsible
	for closing it after finishing compression.
*/
GLOBAL(void)
jpeg_freeimage_dst (j_compress_ptr cinfo, fi_handle outfile, FreeImageIO *io) {
	freeimage_dst_ptr dest;

	if (cinfo->dest == NULL) {
		cinfo->dest = (struct jpeg_destination_mgr *)(*cinfo->mem->alloc_small)
			((j_common_ptr) cinfo, JPOOL_PERMANENT, sizeof(DestinationManager));
	}

	dest = (freeimage_dst_ptr) cinfo->dest;
	dest->pub.init_destination = init_destination;
	dest->pub.empty_output_buffer = empty_output_buffer;
	dest->pub.term_destination = term_destination;
	dest->outfile = outfile;
	dest->m_io = io;
}

// ----------------------------------------------------------
//   Special markers read functions
// ----------------------------------------------------------

/**
	Read JPEG_COM marker (comment)
*/
static BOOL 
jpeg_read_comment(FIBITMAP *dib, const BYTE *dataptr, unsigned int datalen) {
	size_t length = datalen;
	BYTE *profile = (BYTE*)dataptr;

	// read the comment
	char *value = (char*)malloc((length + 1) * sizeof(char));
	if(value == NULL) return FALSE;
	memcpy(value, profile, length);
	value[length] = '\0';

	// create a tag
	FITAG *tag = FreeImage_CreateTag();
	if(tag) {
		unsigned int count = (unsigned int)length + 1;	// includes the null value

		FreeImage_SetTagID(tag, JPEG_COM);
		FreeImage_SetTagKey(tag, "Comment");
		FreeImage_SetTagLength(tag, count);
		FreeImage_SetTagCount(tag, count);
		FreeImage_SetTagType(tag, FIDT_ASCII);
		FreeImage_SetTagValue(tag, value);
		
		// store the tag
		FreeImage_SetMetadata(FIMD_COMMENTS, dib, FreeImage_GetTagKey(tag), tag);

		// destroy the tag
		FreeImage_DeleteTag(tag);
	}

	free(value);

	return TRUE;
}

/** 
	Read JPEG_APP2 marker (ICC profile)
*/

/**
Handy subroutine to test whether a saved marker is an ICC profile marker.
*/
static BOOL 
marker_is_icc(jpeg_saved_marker_ptr marker) {
    // marker identifying string "ICC_PROFILE" (null-terminated)
	const BYTE icc_signature[12] = { 0x49, 0x43, 0x43, 0x5F, 0x50, 0x52, 0x4F, 0x46, 0x49, 0x4C, 0x45, 0x00 };

	if(marker->marker == ICC_MARKER) {
		// verify the identifying string
		if(marker->data_length >= ICC_HEADER_SIZE) {
			if(memcmp(icc_signature, marker->data, sizeof(icc_signature)) == 0) {
				return TRUE;
			}
		}
	}

	return FALSE;
}

/**
  See if there was an ICC profile in the JPEG file being read;
  if so, reassemble and return the profile data.

  TRUE is returned if an ICC profile was found, FALSE if not.
  If TRUE is returned, *icc_data_ptr is set to point to the
  returned data, and *icc_data_len is set to its length.
  
  IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
  and must be freed by the caller with free() when the caller no longer
  needs it.  (Alternatively, we could write this routine to use the
  IJG library's memory allocator, so that the data would be freed implicitly
  at jpeg_finish_decompress() time.  But it seems likely that many apps
  will prefer to have the data stick around after decompression finishes.)
  
  NOTE: if the file contains invalid ICC APP2 markers, we just silently
  return FALSE.  You might want to issue an error message instead.
*/
static BOOL 
jpeg_read_icc_profile(j_decompress_ptr cinfo, JOCTET **icc_data_ptr, unsigned *icc_data_len) {
	jpeg_saved_marker_ptr marker;
	int num_markers = 0;
	int seq_no;
	JOCTET *icc_data;
	unsigned total_length;

	const int MAX_SEQ_NO = 255;			// sufficient since marker numbers are bytes
	BYTE marker_present[MAX_SEQ_NO+1];	// 1 if marker found
	unsigned data_length[MAX_SEQ_NO+1];	// size of profile data in marker
	unsigned data_offset[MAX_SEQ_NO+1];	// offset for data in marker
	
	*icc_data_ptr = NULL;		// avoid confusion if FALSE return
	*icc_data_len = 0;
	
	/**
	this first pass over the saved markers discovers whether there are
	any ICC markers and verifies the consistency of the marker numbering.
	*/
	
	memset(marker_present, 0, (MAX_SEQ_NO + 1));
	
	for(marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
		if (marker_is_icc(marker)) {
			if (num_markers == 0) {
				// number of markers
				num_markers = GETJOCTET(marker->data[13]);
			}
			else if (num_markers != GETJOCTET(marker->data[13])) {
				return FALSE;		// inconsistent num_markers fields 
			}
			// sequence number
			seq_no = GETJOCTET(marker->data[12]);
			if (seq_no <= 0 || seq_no > num_markers) {
				return FALSE;		// bogus sequence number 
			}
			if (marker_present[seq_no]) {
				return FALSE;		// duplicate sequence numbers 
			}
			marker_present[seq_no] = 1;
			data_length[seq_no] = marker->data_length - ICC_HEADER_SIZE;
		}
	}
	
	if (num_markers == 0)
		return FALSE;
		
	/**
	check for missing markers, count total space needed,
	compute offset of each marker's part of the data.
	*/
	
	total_length = 0;
	for(seq_no = 1; seq_no <= num_markers; seq_no++) {
		if (marker_present[seq_no] == 0) {
			return FALSE;		// missing sequence number
		}
		data_offset[seq_no] = total_length;
		total_length += data_length[seq_no];
	}
	
	if (total_length <= 0)
		return FALSE;		// found only empty markers ?
	
	// allocate space for assembled data 
	icc_data = (JOCTET *) malloc(total_length * sizeof(JOCTET));
	if (icc_data == NULL)
		return FALSE;		// out of memory
	
	// and fill it in
	for (marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
		if (marker_is_icc(marker)) {
			JOCTET FAR *src_ptr;
			JOCTET *dst_ptr;
			unsigned length;
			seq_no = GETJOCTET(marker->data[12]);
			dst_ptr = icc_data + data_offset[seq_no];
			src_ptr = marker->data + ICC_HEADER_SIZE;
			length = data_length[seq_no];
			while (length--) {
				*dst_ptr++ = *src_ptr++;
			}
		}
	}
	
	*icc_data_ptr = icc_data;
	*icc_data_len = total_length;
	
	return TRUE;
}

/**
	Read JPEG_APPD marker (IPTC or Adobe Photoshop profile)
*/
static BOOL 
jpeg_read_iptc_profile(FIBITMAP *dib, const BYTE *dataptr, unsigned int datalen) {
	return read_iptc_profile(dib, dataptr, datalen);
}

/**
	Read JPEG_APP1 marker (XMP profile)
	@param dib Input FIBITMAP
	@param dataptr Pointer to the APP1 marker
	@param datalen APP1 marker length
	@return Returns TRUE if successful, FALSE otherwise
*/
static BOOL  
jpeg_read_xmp_profile(FIBITMAP *dib, const BYTE *dataptr, unsigned int datalen) {
	// marker identifying string for XMP (null terminated)
	const char *xmp_signature = "http://ns.adobe.com/xap/1.0/";
	// XMP signature is 29 bytes long
	const size_t xmp_signature_size = strlen(xmp_signature) + 1;

	size_t length = datalen;
	BYTE *profile = (BYTE*)dataptr;

	if(length <= xmp_signature_size) {
		// avoid reading corrupted or empty data 
		return FALSE;
	}

	// verify the identifying string

	if(memcmp(xmp_signature, profile, strlen(xmp_signature)) == 0) {
		// XMP profile

		profile += xmp_signature_size;
		length  -= xmp_signature_size;

		// create a tag
		FITAG *tag = FreeImage_CreateTag();
		if(tag) {
			FreeImage_SetTagID(tag, JPEG_APP0+1);	// 0xFFE1
			FreeImage_SetTagKey(tag, g_TagLib_XMPFieldName);
			FreeImage_SetTagLength(tag, (DWORD)length);
			FreeImage_SetTagCount(tag, (DWORD)length);
			FreeImage_SetTagType(tag, FIDT_ASCII);
			FreeImage_SetTagValue(tag, profile);
			
			// store the tag
			FreeImage_SetMetadata(FIMD_XMP, dib, FreeImage_GetTagKey(tag), tag);

			// destroy the tag
			FreeImage_DeleteTag(tag);
		}

		return TRUE;
	}

	return FALSE;
}

/**
	Read JPEG_APP1 marker (Exif profile)
	@param dib Input FIBITMAP
	@param dataptr Pointer to the APP1 marker
	@param datalen APP1 marker length
	@return Returns TRUE if successful, FALSE otherwise
*/
static BOOL  
jpeg_read_exif_profile_raw(FIBITMAP *dib, const BYTE *profile, unsigned int length) {
    // marker identifying string for Exif = "Exif\0\0"
    BYTE exif_signature[6] = { 0x45, 0x78, 0x69, 0x66, 0x00, 0x00 };

	// verify the identifying string
	if(memcmp(exif_signature, profile, sizeof(exif_signature)) != 0) {
		// not an Exif profile
		return FALSE;
	}

	// create a tag
	FITAG *tag = FreeImage_CreateTag();
	if(tag) {
		FreeImage_SetTagID(tag, EXIF_MARKER);	// (JPEG_APP0 + 1) => EXIF marker / Adobe XMP marker
		FreeImage_SetTagKey(tag, g_TagLib_ExifRawFieldName);
		FreeImage_SetTagLength(tag, (DWORD)length);
		FreeImage_SetTagCount(tag, (DWORD)length);
		FreeImage_SetTagType(tag, FIDT_BYTE);
		FreeImage_SetTagValue(tag, profile);

		// store the tag
		FreeImage_SetMetadata(FIMD_EXIF_RAW, dib, FreeImage_GetTagKey(tag), tag);

		// destroy the tag
		FreeImage_DeleteTag(tag);

		return TRUE;
	}

	return FALSE;
}

/**
	Read JFIF "JFXX" extension APP0 marker
	@param dib Input FIBITMAP
	@param dataptr Pointer to the APP0 marker
	@param datalen APP0 marker length
	@return Returns TRUE if successful, FALSE otherwise
*/
static BOOL 
jpeg_read_jfxx(FIBITMAP *dib, const BYTE *dataptr, unsigned int datalen) {
	if(datalen < 6) {
		return FALSE;
	}
	
	const int id_length = 5;
	const BYTE *data = dataptr + id_length;
	unsigned remaining = datalen - id_length;
		
	const BYTE type = *data;
	++data, --remaining;

	switch(type) {
		case JFXX_TYPE_JPEG:
		{
			// load the thumbnail
			FIMEMORY* hmem = FreeImage_OpenMemory(const_cast<BYTE*>(data), remaining);
			FIBITMAP* thumbnail = FreeImage_LoadFromMemory(FIF_JPEG, hmem);
			FreeImage_CloseMemory(hmem);
			// store the thumbnail
			FreeImage_SetThumbnail(dib, thumbnail);
			// then delete it
			FreeImage_Unload(thumbnail);
			break;
		}
		case JFXX_TYPE_8bit:
			// colormapped uncompressed thumbnail (no supported)
			break;
		case JFXX_TYPE_24bit:
			// truecolor uncompressed thumbnail (no supported)
			break;
		default:
			break;
	}

	return TRUE;
}


/**
	Read JPEG special markers
*/
static BOOL 
read_markers(j_decompress_ptr cinfo, FIBITMAP *dib) {
	jpeg_saved_marker_ptr marker;

	for(marker = cinfo->marker_list; marker != NULL; marker = marker->next) {
		switch(marker->marker) {
			case JPEG_APP0:
				// JFIF is handled by libjpeg already, handle JFXX
				if(memcmp(marker->data, "JFIF" , 5) == 0) {
					continue;
				}
				if(memcmp(marker->data, "JFXX" , 5) == 0) {
					if(!cinfo->saw_JFIF_marker || cinfo->JFIF_minor_version < 2) {
						FreeImage_OutputMessageProc(s_format_id, "Warning: non-standard JFXX segment");
					}					
					jpeg_read_jfxx(dib, marker->data, marker->data_length);
				}
				// other values such as 'Picasa' : ignore safely unknown APP0 marker
				break;
			case JPEG_COM:
				// JPEG comment
				jpeg_read_comment(dib, marker->data, marker->data_length);
				break;
			case EXIF_MARKER:
				// Exif or Adobe XMP profile
				jpeg_read_exif_profile(dib, marker->data, marker->data_length);
				jpeg_read_xmp_profile(dib, marker->data, marker->data_length);
				jpeg_read_exif_profile_raw(dib, marker->data, marker->data_length);
				break;
			case IPTC_MARKER:
				// IPTC/NAA or Adobe Photoshop profile
				jpeg_read_iptc_profile(dib, marker->data, marker->data_length);
				break;
		}
	}

	// ICC profile
	BYTE *icc_profile = NULL;
	unsigned icc_length = 0;

	if( jpeg_read_icc_profile(cinfo, &icc_profile, &icc_length) ) {
		// copy ICC profile data
		FreeImage_CreateICCProfile(dib, icc_profile, icc_length);
		// clean up
		free(icc_profile);
	}

	return TRUE;
}

// ----------------------------------------------------------
//   Special markers write functions
// ----------------------------------------------------------

/**
	Write JPEG_COM marker (comment)
*/
static BOOL 
jpeg_write_comment(j_compress_ptr cinfo, FIBITMAP *dib) {
	FITAG *tag = NULL;

	// write user comment as a JPEG_COM marker
	FreeImage_GetMetadata(FIMD_COMMENTS, dib, "Comment", &tag);
	if(tag) {
		const char *tag_value = (char*)FreeImage_GetTagValue(tag);

		if(NULL != tag_value) {
			for(long i = 0; i < (long)strlen(tag_value); i+= MAX_BYTES_IN_MARKER) {
				jpeg_write_marker(cinfo, JPEG_COM, (BYTE*)tag_value + i, MIN((long)strlen(tag_value + i), MAX_BYTES_IN_MARKER));
			}
			return TRUE;
		}
	}
	return FALSE;
}

/** 
	Write JPEG_APP2 marker (ICC profile)
*/
static BOOL 
jpeg_write_icc_profile(j_compress_ptr cinfo, FIBITMAP *dib) {
    // marker identifying string "ICC_PROFILE" (null-terminated)
	BYTE icc_signature[12] = { 0x49, 0x43, 0x43, 0x5F, 0x50, 0x52, 0x4F, 0x46, 0x49, 0x4C, 0x45, 0x00 };

	FIICCPROFILE *iccProfile = FreeImage_GetICCProfile(dib);

	if (iccProfile->size && iccProfile->data) {
		// ICC_HEADER_SIZE: ICC signature is 'ICC_PROFILE' + 2 bytes

		BYTE *profile = (BYTE*)malloc((iccProfile->size + ICC_HEADER_SIZE) * sizeof(BYTE));
		if(profile == NULL) return FALSE;
		memcpy(profile, icc_signature, 12);

		for(long i = 0; i < (long)iccProfile->size; i += MAX_DATA_BYTES_IN_MARKER) {
			unsigned length = MIN((long)(iccProfile->size - i), MAX_DATA_BYTES_IN_MARKER);
			// sequence number
			profile[12] = (BYTE) ((i / MAX_DATA_BYTES_IN_MARKER) + 1);
			// number of markers
			profile[13] = (BYTE) (iccProfile->size / MAX_DATA_BYTES_IN_MARKER + 1);

			memcpy(profile + ICC_HEADER_SIZE, (BYTE*)iccProfile->data + i, length);
			jpeg_write_marker(cinfo, ICC_MARKER, profile, (length + ICC_HEADER_SIZE));
        }

		free(profile);

		return TRUE;		
	}
	
	return FALSE;
}

/** 
	Write JPEG_APPD marker (IPTC or Adobe Photoshop profile)
	@return Returns TRUE if successful, FALSE otherwise
*/
static BOOL  
jpeg_write_iptc_profile(j_compress_ptr cinfo, FIBITMAP *dib) {
	//const char *ps_header = "Photoshop 3.0\x08BIM\x04\x04\x0\x0\x0\x0";
	const unsigned tag_length = 26;

	if(FreeImage_GetMetadataCount(FIMD_IPTC, dib)) {
		BYTE *profile = NULL;
		unsigned profile_size = 0;

		// create a binary profile
		if(write_iptc_profile(dib, &profile, &profile_size)) {

			// write the profile
			for(long i = 0; i < (long)profile_size; i += 65517L) {
				unsigned length = MIN((long)profile_size - i, 65517L);
				unsigned roundup = length & 0x01;	// needed for Photoshop
				BYTE *iptc_profile = (BYTE*)malloc(length + roundup + tag_length);
				if(iptc_profile == NULL) break;
				// Photoshop identification string
				memcpy(&iptc_profile[0], "Photoshop 3.0\x0", 14);
				// 8BIM segment type
				memcpy(&iptc_profile[14], "8BIM\x04\x04\x0\x0\x0\x0", 10);
				// segment size
				iptc_profile[24] = (BYTE)(length >> 8);
				iptc_profile[25] = (BYTE)(length & 0xFF);
				// segment data
				memcpy(&iptc_profile[tag_length], &profile[i], length);
				if(roundup)
					iptc_profile[length + tag_length] = 0;
				jpeg_write_marker(cinfo, IPTC_MARKER, iptc_profile, length + roundup + tag_length);
				free(iptc_profile);
			}

			// release profile
			free(profile);

			return TRUE;
		}
	}

	return FALSE;
}

/** 
	Write JPEG_APP1 marker (XMP profile)
	@return Returns TRUE if successful, FALSE otherwise
*/
static BOOL  
jpeg_write_xmp_profile(j_compress_ptr cinfo, FIBITMAP *dib) {
	// marker identifying string for XMP (null terminated)
	const char *xmp_signature = "http://ns.adobe.com/xap/1.0/";

	FITAG *tag_xmp = NULL;
	FreeImage_GetMetadata(FIMD_XMP, dib, g_TagLib_XMPFieldName, &tag_xmp);

	if(tag_xmp) {
		const BYTE *tag_value = (BYTE*)FreeImage_GetTagValue(tag_xmp);

		if(NULL != tag_value) {
			// XMP signature is 29 bytes long
			unsigned int xmp_header_size = (unsigned int)strlen(xmp_signature) + 1;

			DWORD tag_length = FreeImage_GetTagLength(tag_xmp);

			BYTE *profile = (BYTE*)malloc((tag_length + xmp_header_size) * sizeof(BYTE));
			if(profile == NULL) return FALSE;
			memcpy(profile, xmp_signature, xmp_header_size);

			for(DWORD i = 0; i < tag_length; i += 65504L) {
				unsigned length = MIN((long)(tag_length - i), 65504L);
				
				memcpy(profile + xmp_header_size, tag_value + i, length);
				jpeg_write_marker(cinfo, EXIF_MARKER, profile, (length + xmp_header_size));
			}

			free(profile);

			return TRUE;	
		}
	}

	return FALSE;
}

/** 
	Write JPEG_APP1 marker (Exif profile)
	@return Returns TRUE if successful, FALSE otherwise
*/
static BOOL 
jpeg_write_exif_profile_raw(j_compress_ptr cinfo, FIBITMAP *dib) {
    // marker identifying string for Exif = "Exif\0\0"
    BYTE exif_signature[6] = { 0x45, 0x78, 0x69, 0x66, 0x00, 0x00 };

	FITAG *tag_exif = NULL;
	FreeImage_GetMetadata(FIMD_EXIF_RAW, dib, g_TagLib_ExifRawFieldName, &tag_exif);

	if(tag_exif) {
		const BYTE *tag_value = (BYTE*)FreeImage_GetTagValue(tag_exif);
		
		// verify the identifying string
		if(memcmp(exif_signature, tag_value, sizeof(exif_signature)) != 0) {
			// not an Exif profile
			return FALSE;
		}

		if(NULL != tag_value) {
			DWORD tag_length = FreeImage_GetTagLength(tag_exif);

			BYTE *profile = (BYTE*)malloc(tag_length * sizeof(BYTE));
			if(profile == NULL) return FALSE;

			for(DWORD i = 0; i < tag_length; i += 65504L) {
				unsigned length = MIN((long)(tag_length - i), 65504L);
				
				memcpy(profile, tag_value + i, length);
				jpeg_write_marker(cinfo, EXIF_MARKER, profile, length);
			}

			free(profile);

			return TRUE;	
		}
	}

	return FALSE;
}

/**
	Write thumbnail (JFXX segment, JPEG compressed)
*/
static BOOL
jpeg_write_jfxx(j_compress_ptr cinfo, FIBITMAP *dib) {
	// get the thumbnail to be stored
	FIBITMAP* thumbnail = FreeImage_GetThumbnail(dib);
	if(!thumbnail) {
		return TRUE;
	}
	// check for a compatible output format
	if((FreeImage_GetImageType(thumbnail) != FIT_BITMAP) || (FreeImage_GetBPP(thumbnail) != 8) && (FreeImage_GetBPP(thumbnail) != 24)) {
		FreeImage_OutputMessageProc(s_format_id, FI_MSG_WARNING_INVALID_THUMBNAIL);
		return FALSE;
	}
	
	// stores the thumbnail as a baseline JPEG into a memory block
	// return the memory block only if its size is within JFXX marker size limit!
	FIMEMORY *stream = FreeImage_OpenMemory();
	
	if(FreeImage_SaveToMemory(FIF_JPEG, thumbnail, stream, JPEG_BASELINE)) {
		// check that the memory block size is within JFXX marker size limit
		FreeImage_SeekMemory(stream, 0, SEEK_END);
		const long eof = FreeImage_TellMemory(stream);
		if(eof > MAX_JFXX_THUMB_SIZE) {
			FreeImage_OutputMessageProc(s_format_id, "Warning: attached thumbnail is %d bytes larger than maximum supported size - Thumbnail saving aborted", eof - MAX_JFXX_THUMB_SIZE);
			FreeImage_CloseMemory(stream);
			return FALSE;
		}
	} else {
		FreeImage_CloseMemory(stream);
		return FALSE;
	}

	BYTE* thData = NULL;
	DWORD thSize = 0;
	
	FreeImage_AcquireMemory(stream, &thData, &thSize);	
	
	BYTE id_length = 5; //< "JFXX"
	BYTE type = JFXX_TYPE_JPEG;
	
	DWORD totalsize = id_length + sizeof(type) + thSize;
	jpeg_write_m_header(cinfo, JPEG_APP0, totalsize);
	
	jpeg_write_m_byte(cinfo, 'J');
	jpeg_write_m_byte(cinfo, 'F');
	jpeg_write_m_byte(cinfo, 'X');
	jpeg_write_m_byte(cinfo, 'X');
	jpeg_write_m_byte(cinfo, '\0');
	
	jpeg_write_m_byte(cinfo, type);
	
	// write thumbnail to destination.
	// We "cram it straight into the data destination module", because write_m_byte is slow
	
	freeimage_dst_ptr dest = (freeimage_dst_ptr) cinfo->dest;
	
	BYTE* & out = dest->pub.next_output_byte;
	size_t & bufRemain = dest->pub.free_in_buffer;
	
	const BYTE *thData_end = thData + thSize;

	while(thData < thData_end) {
		*(out)++ = *(thData)++;
		if (--bufRemain == 0) {	
			// buffer full - flush
			if (!dest->pub.empty_output_buffer(cinfo)) {
				break;
			}
		}
	}
	
	FreeImage_CloseMemory(stream);

	return TRUE;
}

/**
	Write JPEG special markers
*/
static BOOL 
write_markers(j_compress_ptr cinfo, FIBITMAP *dib) {
	// write thumbnail as a JFXX marker
	jpeg_write_jfxx(cinfo, dib);

	// write user comment as a JPEG_COM marker
	jpeg_write_comment(cinfo, dib);

	// write ICC profile
	jpeg_write_icc_profile(cinfo, dib);

	// write IPTC profile
	jpeg_write_iptc_profile(cinfo, dib);

	// write Adobe XMP profile
	jpeg_write_xmp_profile(cinfo, dib);

	// write Exif raw data
	jpeg_write_exif_profile_raw(cinfo, dib);

	return TRUE;
}

// ------------------------------------------------------------
//   Keep original size info when using scale option on loading
// ------------------------------------------------------------
static void 
store_size_info(FIBITMAP *dib, JDIMENSION width, JDIMENSION height) {
	char buffer[256];
	// create a tag
	FITAG *tag = FreeImage_CreateTag();
	if(tag) {
		size_t length = 0;
		// set the original width
		sprintf(buffer, "%d", (int)width);
		length = strlen(buffer) + 1;	// include the NULL/0 value
		FreeImage_SetTagKey(tag, "OriginalJPEGWidth");
		FreeImage_SetTagLength(tag, (DWORD)length);
		FreeImage_SetTagCount(tag, (DWORD)length);
		FreeImage_SetTagType(tag, FIDT_ASCII);
		FreeImage_SetTagValue(tag, buffer);
		FreeImage_SetMetadata(FIMD_COMMENTS, dib, FreeImage_GetTagKey(tag), tag);
		// set the original height
		sprintf(buffer, "%d", (int)height);
		length = strlen(buffer) + 1;	// include the NULL/0 value
		FreeImage_SetTagKey(tag, "OriginalJPEGHeight");
		FreeImage_SetTagLength(tag, (DWORD)length);
		FreeImage_SetTagCount(tag, (DWORD)length);
		FreeImage_SetTagType(tag, FIDT_ASCII);
		FreeImage_SetTagValue(tag, buffer);
		FreeImage_SetMetadata(FIMD_COMMENTS, dib, FreeImage_GetTagKey(tag), tag);
		// destroy the tag
		FreeImage_DeleteTag(tag);
	}
}

// ------------------------------------------------------------
//   Rotate a dib according to Exif info
// ------------------------------------------------------------

static void 
rotate_exif(FIBITMAP **dib) {
	// check for Exif rotation
	if(FreeImage_GetMetadataCount(FIMD_EXIF_MAIN, *dib)) {
		FIBITMAP *rotated = NULL;
		// process Exif rotation
		FITAG *tag = NULL;
		FreeImage_GetMetadata(FIMD_EXIF_MAIN, *dib, "Orientation", &tag);
		if(tag != NULL) {
			if(FreeImage_GetTagID(tag) == TAG_ORIENTATION) {
				unsigned short orientation = *((unsigned short *)FreeImage_GetTagValue(tag));
				switch (orientation) {
					case 1:		// "top, left side" => 0°
						break;
					case 2:		// "top, right side" => flip left-right
						FreeImage_FlipHorizontal(*dib);
						break;
					case 3:		// "bottom, right side"; => -180°
						rotated = FreeImage_Rotate(*dib, 180);
						FreeImage_Unload(*dib);
						*dib = rotated;
						break;
					case 4:		// "bottom, left side" => flip up-down
						FreeImage_FlipVertical(*dib);
						break;
					case 5:		// "left side, top" => +90° + flip up-down
						rotated = FreeImage_Rotate(*dib, 90);
						FreeImage_Unload(*dib);
						*dib = rotated;
						FreeImage_FlipVertical(*dib);
						break;
					case 6:		// "right side, top" => -90°
						rotated = FreeImage_Rotate(*dib, -90);
						FreeImage_Unload(*dib);
						*dib = rotated;
						break;
					case 7:		// "right side, bottom" => -90° + flip up-down
						rotated = FreeImage_Rotate(*dib, -90);
						FreeImage_Unload(*dib);
						*dib = rotated;
						FreeImage_FlipVertical(*dib);
						break;
					case 8:		// "left side, bottom" => +90°
						rotated = FreeImage_Rotate(*dib, 90);
						FreeImage_Unload(*dib);
						*dib = rotated;
						break;
					default:
						break;
				}
			}
		}
	}
}


// ==========================================================
// Plugin Implementation
// ==========================================================

static const char * DLL_CALLCONV
Format() {
	return "JPEG";
}

static const char * DLL_CALLCONV
Description() {
	return "JPEG - JFIF Compliant";
}

static const char * DLL_CALLCONV
Extension() {
	return "jpg,jif,jpeg,jpe";
}

static const char * DLL_CALLCONV
RegExpr() {
	return "^\377\330\377";
}

static const char * DLL_CALLCONV
MimeType() {
	return "image/jpeg";
}

static BOOL DLL_CALLCONV
Validate(FreeImageIO *io, fi_handle handle) {
	BYTE jpeg_signature[] = { 0xFF, 0xD8 };
	BYTE signature[2] = { 0, 0 };

	io->read_proc(signature, 1, sizeof(jpeg_signature), handle);

	return (memcmp(jpeg_signature, signature, sizeof(jpeg_signature)) == 0);
}

static BOOL DLL_CALLCONV
SupportsExportDepth(int depth) {
	return (
			(depth == 8) ||
			(depth == 24)
		);
}

static BOOL DLL_CALLCONV 
SupportsExportType(FREE_IMAGE_TYPE type) {
	return (type == FIT_BITMAP) ? TRUE : FALSE;
}

static BOOL DLL_CALLCONV
SupportsICCProfiles() {
	return TRUE;
}

static BOOL DLL_CALLCONV
SupportsNoPixels() {
	return TRUE;
}

// ----------------------------------------------------------

static FIBITMAP * DLL_CALLCONV
Load(FreeImageIO *io, fi_handle handle, int page, int flags, void *data) {
	if (handle) {
		FIBITMAP *dib = NULL;

		BOOL header_only = (flags & FIF_LOAD_NOPIXELS) == FIF_LOAD_NOPIXELS;

		// set up the jpeglib structures

		struct jpeg_decompress_struct cinfo;
		ErrorManager fi_error_mgr;

		try {

			// step 1: allocate and initialize JPEG decompression object

			// we set up the normal JPEG error routines, then override error_exit & output_message
			cinfo.err = jpeg_std_error(&fi_error_mgr.pub);
			fi_error_mgr.pub.error_exit     = jpeg_error_exit;
			fi_error_mgr.pub.output_message = jpeg_output_message;
			
			// establish the setjmp return context for jpeg_error_exit to use
			if (setjmp(fi_error_mgr.setjmp_buffer)) {
				// If we get here, the JPEG code has signaled an error.
				// We need to clean up the JPEG object, close the input file, and return.
				jpeg_destroy_decompress(&cinfo);
				throw (const char*)NULL;
			}

			jpeg_create_decompress(&cinfo);

			// step 2a: specify data source (eg, a handle)

			jpeg_freeimage_src(&cinfo, handle, io);

			// step 2b: save special markers for later reading
			
			jpeg_save_markers(&cinfo, JPEG_COM, 0xFFFF);
			for(int m = 0; m < 16; m++) {
				jpeg_save_markers(&cinfo, JPEG_APP0 + m, 0xFFFF);
			}

			// step 3: read handle parameters with jpeg_read_header()

			jpeg_read_header(&cinfo, TRUE);

			// step 4: set parameters for decompression

			unsigned int scale_denom = 1;		// fraction by which to scale image
			int	requested_size = flags >> 16;	// requested user size in pixels
			if(requested_size > 0) {
				// the JPEG codec can perform x2, x4 or x8 scaling on loading
				// try to find the more appropriate scaling according to user's need
				double scale = MAX((double)cinfo.image_width, (double)cinfo.image_height) / (double)requested_size;
				if(scale >= 8) {
					scale_denom = 8;
				} else if(scale >= 4) {
					scale_denom = 4;
				} else if(scale >= 2) {
					scale_denom = 2;
				}
			}
			cinfo.scale_num = 1;
			cinfo.scale_denom = scale_denom;

			if ((flags & JPEG_ACCURATE) != JPEG_ACCURATE) {
				cinfo.dct_method          = JDCT_IFAST;
				cinfo.do_fancy_upsampling = FALSE;
			}

			// step 5a: start decompressor and calculate output width and height

			jpeg_start_decompress(&cinfo);

			// step 5b: allocate dib and init header

			if((cinfo.num_components == 4) && (cinfo.out_color_space == JCS_CMYK)) {
				// CMYK image
				if((flags & JPEG_CMYK) == JPEG_CMYK) {
					// load as CMYK
					dib = FreeImage_AllocateHeader(header_only, cinfo.output_width, cinfo.output_height, 32, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
					if(!dib) throw FI_MSG_ERROR_DIB_MEMORY;
					FreeImage_GetICCProfile(dib)->flags |= FIICC_COLOR_IS_CMYK;
				} else {
					// load as CMYK and convert to RGB
					dib = FreeImage_AllocateHeader(header_only, cinfo.output_width, cinfo.output_height, 24, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
					if(!dib) throw FI_MSG_ERROR_DIB_MEMORY;
				}
			} else {
				// RGB or greyscale image
				dib = FreeImage_AllocateHeader(header_only, cinfo.output_width, cinfo.output_height, 8 * cinfo.num_components, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
				if(!dib) throw FI_MSG_ERROR_DIB_MEMORY;

				if (cinfo.num_components == 1) {
					// build a greyscale palette
					RGBQUAD *colors = FreeImage_GetPalette(dib);

					for (int i = 0; i < 256; i++) {
						colors[i].rgbRed   = (BYTE)i;
						colors[i].rgbGreen = (BYTE)i;
						colors[i].rgbBlue  = (BYTE)i;
					}
				}
			}
			if(scale_denom != 1) {
				// store original size info if a scaling was requested
				store_size_info(dib, cinfo.image_width, cinfo.image_height);
			}

			// step 5c: handle metrices

			if (cinfo.density_unit == 1) {
				// dots/inch
				FreeImage_SetDotsPerMeterX(dib, (unsigned) (((float)cinfo.X_density) / 0.0254000 + 0.5));
				FreeImage_SetDotsPerMeterY(dib, (unsigned) (((float)cinfo.Y_density) / 0.0254000 + 0.5));
			} else if (cinfo.density_unit == 2) {
				// dots/cm
				FreeImage_SetDotsPerMeterX(dib, (unsigned) (cinfo.X_density * 100));
				FreeImage_SetDotsPerMeterY(dib, (unsigned) (cinfo.Y_density * 100));
			}
			
			// step 6: read special markers
			
			read_markers(&cinfo, dib);

			// --- header only mode => clean-up and return

			if (header_only) {
				// release JPEG decompression object
				jpeg_destroy_decompress(&cinfo);
				// return header data
				return dib;
			}

			// step 7a: while (scan lines remain to be read) jpeg_read_scanlines(...);

			if((cinfo.out_color_space == JCS_CMYK) && ((flags & JPEG_CMYK) != JPEG_CMYK)) {
				// convert from CMYK to RGB

				JSAMPARRAY buffer;		// output row buffer
				unsigned row_stride;	// physical row width in output buffer

				// JSAMPLEs per row in output buffer
				row_stride = cinfo.output_width * cinfo.output_components;
				// make a one-row-high sample array that will go away when done with image
				buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

				while (cinfo.output_scanline < cinfo.output_height) {
					JSAMPROW src = buffer[0];
					JSAMPROW dst = FreeImage_GetScanLine(dib, cinfo.output_height - cinfo.output_scanline - 1);

					jpeg_read_scanlines(&cinfo, buffer, 1);

					for(unsigned x = 0; x < cinfo.output_width; x++) {
						WORD K = (WORD)src[3];
						dst[FI_RGBA_RED]   = (BYTE)((K * src[0]) / 255);	// C -> R
						dst[FI_RGBA_GREEN] = (BYTE)((K * src[1]) / 255);	// M -> G
						dst[FI_RGBA_BLUE]  = (BYTE)((K * src[2]) / 255);	// Y -> B
						src += 4;
						dst += 3;
					}
				}
			} else if((cinfo.out_color_space == JCS_CMYK) && ((flags & JPEG_CMYK) == JPEG_CMYK)) {
				// convert from LibJPEG CMYK to standard CMYK

				JSAMPARRAY buffer;		// output row buffer
				unsigned row_stride;	// physical row width in output buffer

				// JSAMPLEs per row in output buffer
				row_stride = cinfo.output_width * cinfo.output_components;
				// make a one-row-high sample array that will go away when done with image
				buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

				while (cinfo.output_scanline < cinfo.output_height) {
					JSAMPROW src = buffer[0];
					JSAMPROW dst = FreeImage_GetScanLine(dib, cinfo.output_height - cinfo.output_scanline - 1);

					jpeg_read_scanlines(&cinfo, buffer, 1);

					for(unsigned x = 0; x < cinfo.output_width; x++) {
						// CMYK pixels are inverted
						dst[0] = ~src[0];	// C
						dst[1] = ~src[1];	// M
						dst[2] = ~src[2];	// Y
						dst[3] = ~src[3];	// K
						src += 4;
						dst += 4;
					}
				}

			} else {
				// normal case (RGB or greyscale image)

				while (cinfo.output_scanline < cinfo.output_height) {
					JSAMPROW dst = FreeImage_GetScanLine(dib, cinfo.output_height - cinfo.output_scanline - 1);

					jpeg_read_scanlines(&cinfo, &dst, 1);
				}

				// step 7b: swap red and blue components (see LibJPEG/jmorecfg.h: #define RGB_RED, ...)
				// The default behavior of the JPEG library is kept "as is" because LibTIFF uses 
				// LibJPEG "as is".

#if FREEIMAGE_COLORORDER == FREEIMAGE_COLORORDER_BGR
				SwapRedBlue32(dib);
#endif
			}

			// step 8: finish decompression

			jpeg_finish_decompress(&cinfo);

			// step 9: release JPEG decompression object

			jpeg_destroy_decompress(&cinfo);

			// check for automatic Exif rotation
			if(!header_only && ((flags & JPEG_EXIFROTATE) == JPEG_EXIFROTATE)) {
				rotate_exif(&dib);
			}

			// everything went well. return the loaded dib

			return dib;

		} catch (const char *text) {
			jpeg_destroy_decompress(&cinfo);
			if(NULL != dib) {
				FreeImage_Unload(dib);
			}
			if(NULL != text) {
				FreeImage_OutputMessageProc(s_format_id, text);
			}
		}
	}

	return NULL;
}

// ----------------------------------------------------------

static BOOL DLL_CALLCONV
Save(FreeImageIO *io, FIBITMAP *dib, fi_handle handle, int page, int flags, void *data) {
	if ((dib) && (handle)) {
		try {
			// Check dib format

			const char *sError = "only 24-bit highcolor or 8-bit greyscale/palette bitmaps can be saved as JPEG";

			FREE_IMAGE_COLOR_TYPE color_type = FreeImage_GetColorType(dib);
			WORD bpp = (WORD)FreeImage_GetBPP(dib);

			if ((bpp != 24) && (bpp != 8)) {
				throw sError;
			}

			if(bpp == 8) {
				// allow grey, reverse grey and palette 
				if ((color_type != FIC_MINISBLACK) && (color_type != FIC_MINISWHITE) && (color_type != FIC_PALETTE)) {
					throw sError;
				}
			}


			struct jpeg_compress_struct cinfo;
			ErrorManager fi_error_mgr;

			// Step 1: allocate and initialize JPEG compression object

			// we set up the normal JPEG error routines, then override error_exit & output_message
			cinfo.err = jpeg_std_error(&fi_error_mgr.pub);
			fi_error_mgr.pub.error_exit     = jpeg_error_exit;
			fi_error_mgr.pub.output_message = jpeg_output_message;
			
			// establish the setjmp return context for jpeg_error_exit to use
			if (setjmp(fi_error_mgr.setjmp_buffer)) {
				// If we get here, the JPEG code has signaled an error.
				// We need to clean up the JPEG object, close the input file, and return.
				jpeg_destroy_compress(&cinfo);
				throw (const char*)NULL;
			}

			// Now we can initialize the JPEG compression object

			jpeg_create_compress(&cinfo);

			// Step 2: specify data destination (eg, a file)

			jpeg_freeimage_dst(&cinfo, handle, io);

			// Step 3: set parameters for compression 

			cinfo.image_width = FreeImage_GetWidth(dib);
			cinfo.image_height = FreeImage_GetHeight(dib);

			switch(color_type) {
				case FIC_MINISBLACK :
				case FIC_MINISWHITE :
					cinfo.in_color_space = JCS_GRAYSCALE;
					cinfo.input_components = 1;
					break;

				default :
					cinfo.in_color_space = JCS_RGB;
					cinfo.input_components = 3;
					break;
			}

			jpeg_set_defaults(&cinfo);

		    // progressive-JPEG support
			if((flags & JPEG_PROGRESSIVE) == JPEG_PROGRESSIVE) {
				jpeg_simple_progression(&cinfo);
			}
			
			// compute optimal Huffman coding tables for the image
			if((flags & JPEG_OPTIMIZE) == JPEG_OPTIMIZE) {
				cinfo.optimize_coding = TRUE;
			}

			// Set JFIF density parameters from the DIB data

			cinfo.X_density = (UINT16) (0.5 + 0.0254 * FreeImage_GetDotsPerMeterX(dib));
			cinfo.Y_density = (UINT16) (0.5 + 0.0254 * FreeImage_GetDotsPerMeterY(dib));
			cinfo.density_unit = 1;	// dots / inch

			// thumbnail support (JFIF 1.02 extension markers)
			if(FreeImage_GetThumbnail(dib) != NULL) {
				cinfo.write_JFIF_header = 1; //<### force it, though when color is CMYK it will be incorrect
				cinfo.JFIF_minor_version = 2;
			}

			// baseline JPEG support
			if ((flags & JPEG_BASELINE) ==  JPEG_BASELINE) {
				cinfo.write_JFIF_header = 0;	// No marker for non-JFIF colorspaces
				cinfo.write_Adobe_marker = 0;	// write no Adobe marker by default				
			}

			// set subsampling options if required

			if(cinfo.in_color_space == JCS_RGB) {
				if((flags & JPEG_SUBSAMPLING_411) == JPEG_SUBSAMPLING_411) { 
					// 4:1:1 (4x1 1x1 1x1) - CrH 25% - CbH 25% - CrV 100% - CbV 100%
					// the horizontal color resolution is quartered
					cinfo.comp_info[0].h_samp_factor = 4;	// Y 
					cinfo.comp_info[0].v_samp_factor = 1; 
					cinfo.comp_info[1].h_samp_factor = 1;	// Cb 
					cinfo.comp_info[1].v_samp_factor = 1; 
					cinfo.comp_info[2].h_samp_factor = 1;	// Cr 
					cinfo.comp_info[2].v_samp_factor = 1; 
				} else if((flags & JPEG_SUBSAMPLING_420) == JPEG_SUBSAMPLING_420) {
					// 4:2:0 (2x2 1x1 1x1) - CrH 50% - CbH 50% - CrV 50% - CbV 50%
					// the chrominance resolution in both the horizontal and vertical directions is cut in half
					cinfo.comp_info[0].h_samp_factor = 2;	// Y
					cinfo.comp_info[0].v_samp_factor = 2; 
					cinfo.comp_info[1].h_samp_factor = 1;	// Cb
					cinfo.comp_info[1].v_samp_factor = 1; 
					cinfo.comp_info[2].h_samp_factor = 1;	// Cr
					cinfo.comp_info[2].v_samp_factor = 1; 
				} else if((flags & JPEG_SUBSAMPLING_422) == JPEG_SUBSAMPLING_422){ //2x1 (low) 
					// 4:2:2 (2x1 1x1 1x1) - CrH 50% - CbH 50% - CrV 100% - CbV 100%
					// half of the horizontal resolution in the chrominance is dropped (Cb & Cr), 
					// while the full resolution is retained in the vertical direction, with respect to the luminance
					cinfo.comp_info[0].h_samp_factor = 2;	// Y 
					cinfo.comp_info[0].v_samp_factor = 1; 
					cinfo.comp_info[1].h_samp_factor = 1;	// Cb 
					cinfo.comp_info[1].v_samp_factor = 1; 
					cinfo.comp_info[2].h_samp_factor = 1;	// Cr 
					cinfo.comp_info[2].v_samp_factor = 1; 
				} 
				else if((flags & JPEG_SUBSAMPLING_444) == JPEG_SUBSAMPLING_444){ //1x1 (no subsampling) 
					// 4:4:4 (1x1 1x1 1x1) - CrH 100% - CbH 100% - CrV 100% - CbV 100%
					// the resolution of chrominance information (Cb & Cr) is preserved 
					// at the same rate as the luminance (Y) information
					cinfo.comp_info[0].h_samp_factor = 1;	// Y 
					cinfo.comp_info[0].v_samp_factor = 1; 
					cinfo.comp_info[1].h_samp_factor = 1;	// Cb 
					cinfo.comp_info[1].v_samp_factor = 1; 
					cinfo.comp_info[2].h_samp_factor = 1;	// Cr 
					cinfo.comp_info[2].v_samp_factor = 1;  
				} 
			}

			// Step 4: set quality
			// the first 7 bits are reserved for low level quality settings
			// the other bits are high level (i.e. enum-ish)

			int quality;

			if ((flags & JPEG_QUALITYBAD) == JPEG_QUALITYBAD) {
				quality = 10;
			} else if ((flags & JPEG_QUALITYAVERAGE) == JPEG_QUALITYAVERAGE) {
				quality = 25;
			} else if ((flags & JPEG_QUALITYNORMAL) == JPEG_QUALITYNORMAL) {
				quality = 50;
			} else if ((flags & JPEG_QUALITYGOOD) == JPEG_QUALITYGOOD) {
				quality = 75;
			} else 	if ((flags & JPEG_QUALITYSUPERB) == JPEG_QUALITYSUPERB) {
				quality = 100;
			} else {
				if ((flags & 0x7F) == 0) {
					quality = 75;
				} else {
					quality = flags & 0x7F;
				}
			}

			jpeg_set_quality(&cinfo, quality, TRUE); /* limit to baseline-JPEG values */

			// Step 5: Start compressor 

			jpeg_start_compress(&cinfo, TRUE);

			// Step 6: Write special markers
			
			if ((flags & JPEG_BASELINE) !=  JPEG_BASELINE) {
				write_markers(&cinfo, dib);
			}

			// Step 7: while (scan lines remain to be written) 

			if(color_type == FIC_RGB) {
				// 24-bit RGB image : need to swap red and blue channels
				unsigned pitch = FreeImage_GetPitch(dib);
				BYTE *target = (BYTE*)malloc(pitch * sizeof(BYTE));
				if (target == NULL) {
					throw FI_MSG_ERROR_MEMORY;
				}

				while (cinfo.next_scanline < cinfo.image_height) {
					// get a copy of the scanline
					memcpy(target, FreeImage_GetScanLine(dib, FreeImage_GetHeight(dib) - cinfo.next_scanline - 1), pitch);
#if FREEIMAGE_COLORORDER == FREEIMAGE_COLORORDER_BGR
					// swap R and B channels
					BYTE *target_p = target;
					for(unsigned x = 0; x < cinfo.image_width; x++) {
						INPLACESWAP(target_p[0], target_p[2]);
						target_p += 3;
					}
#endif
					// write the scanline
					jpeg_write_scanlines(&cinfo, &target, 1);
				}
				free(target);
			}
			else if(color_type == FIC_MINISBLACK) {
				// 8-bit standard greyscale images
				while (cinfo.next_scanline < cinfo.image_height) {
					JSAMPROW b = FreeImage_GetScanLine(dib, FreeImage_GetHeight(dib) - cinfo.next_scanline - 1);

					jpeg_write_scanlines(&cinfo, &b, 1);
				}
			}
			else if(color_type == FIC_PALETTE) {
				// 8-bit palettized images are converted to 24-bit images
				RGBQUAD *palette = FreeImage_GetPalette(dib);
				BYTE *target = (BYTE*)malloc(cinfo.image_width * 3);
				if (target == NULL) {
					throw FI_MSG_ERROR_MEMORY;
				}

				while (cinfo.next_scanline < cinfo.image_height) {
					BYTE *source = FreeImage_GetScanLine(dib, FreeImage_GetHeight(dib) - cinfo.next_scanline - 1);
					FreeImage_ConvertLine8To24(target, source, cinfo.image_width, palette);

#if FREEIMAGE_COLORORDER == FREEIMAGE_COLORORDER_BGR
					// swap R and B channels
					BYTE *target_p = target;
					for(unsigned x = 0; x < cinfo.image_width; x++) {
						INPLACESWAP(target_p[0], target_p[2]);
						target_p += 3;
					}
#endif


					jpeg_write_scanlines(&cinfo, &target, 1);
				}

				free(target);
			}
			else if(color_type == FIC_MINISWHITE) {
				// reverse 8-bit greyscale image, so reverse grey value on the fly
				unsigned i;
				BYTE reverse[256];
				BYTE *target = (BYTE *)malloc(cinfo.image_width);
				if (target == NULL) {
					throw FI_MSG_ERROR_MEMORY;
				}

				for(i = 0; i < 256; i++) {
					reverse[i] = (BYTE)(255 - i);
				}

				while(cinfo.next_scanline < cinfo.image_height) {
					BYTE *source = FreeImage_GetScanLine(dib, FreeImage_GetHeight(dib) - cinfo.next_scanline - 1);
					for(i = 0; i < cinfo.image_width; i++) {
						target[i] = reverse[ source[i] ];
					}
					jpeg_write_scanlines(&cinfo, &target, 1);
				}

				free(target);
			}

			// Step 8: Finish compression 

			jpeg_finish_compress(&cinfo);

			// Step 9: release JPEG compression object 

			jpeg_destroy_compress(&cinfo);

			return TRUE;

		} catch (const char *text) {
			if(text) {
				FreeImage_OutputMessageProc(s_format_id, text);
			}
			return FALSE;
		} 
	}

	return FALSE;
}

// ==========================================================
//   Init
// ==========================================================

void DLL_CALLCONV
InitJPEG(Plugin *plugin, int format_id) {
	s_format_id = format_id;

	plugin->format_proc = Format;
	plugin->description_proc = Description;
	plugin->extension_proc = Extension;
	plugin->regexpr_proc = RegExpr;
	plugin->open_proc = NULL;
	plugin->close_proc = NULL;
	plugin->pagecount_proc = NULL;
	plugin->pagecapability_proc = NULL;
	plugin->load_proc = Load;
	plugin->save_proc = Save;
	plugin->validate_proc = Validate;
	plugin->mime_proc = MimeType;
	plugin->supports_export_bpp_proc = SupportsExportDepth;
	plugin->supports_export_type_proc = SupportsExportType;
	plugin->supports_icc_profiles_proc = SupportsICCProfiles;
	plugin->supports_no_pixels_proc = SupportsNoPixels;
}