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Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12

1 files changed, 2035 insertions, 0 deletions

diff --git a/src/3rdparty/libtiff/libtiff/tif_jpeg.c b/src/3rdparty/libtiff/libtiff/tif_jpeg.c
new file mode 100644
index 0000000000..74b0d3f860
--- /dev/null
+++ b/src/3rdparty/libtiff/libtiff/tif_jpeg.c
@@ -0,0 +1,2035 @@
+/* $Id: tif_jpeg.c,v 1.50.2.4 2009-08-30 16:21:46 bfriesen Exp $ */
+
+/*
+ * Copyright (c) 1994-1997 Sam Leffler
+ * Copyright (c) 1994-1997 Silicon Graphics, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and 
+ * its documentation for any purpose is hereby granted without fee, provided
+ * that (i) the above copyright notices and this permission notice appear in
+ * all copies of the software and related documentation, and (ii) the names of
+ * Sam Leffler and Silicon Graphics may not be used in any advertising or
+ * publicity relating to the software without the specific, prior written
+ * permission of Sam Leffler and Silicon Graphics.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
+ * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
+ * 
+ * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
+ * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
+ * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+ * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
+ * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
+ * OF THIS SOFTWARE.
+ */
+
+#define WIN32_LEAN_AND_MEAN
+#define VC_EXTRALEAN
+
+#include "tiffiop.h"
+#ifdef JPEG_SUPPORT
+
+/*
+ * TIFF Library
+ *
+ * JPEG Compression support per TIFF Technical Note #2
+ * (*not* per the original TIFF 6.0 spec).
+ *
+ * This file is simply an interface to the libjpeg library written by
+ * the Independent JPEG Group.  You need release 5 or later of the IJG
+ * code, which you can find on the Internet at ftp.uu.net:/graphics/jpeg/.
+ *
+ * Contributed by Tom Lane <tgl@sss.pgh.pa.us>.
+ */
+#include <setjmp.h>
+
+int TIFFFillStrip(TIFF*, tstrip_t);
+int TIFFFillTile(TIFF*, ttile_t);
+
+/* We undefine FAR to avoid conflict with JPEG definition */
+
+#ifdef FAR
+#undef FAR
+#endif
+
+/*
+  Libjpeg's jmorecfg.h defines INT16 and INT32, but only if XMD_H is
+  not defined.  Unfortunately, the MinGW and Borland compilers include
+  a typedef for INT32, which causes a conflict.  MSVC does not include
+  a conficting typedef given the headers which are included.
+*/
+#if defined(__BORLANDC__) || defined(__MINGW32__)
+# define XMD_H 1
+#endif
+
+/*
+   The windows RPCNDR.H file defines boolean, but defines it with the
+   unsigned char size.  You should compile JPEG library using appropriate
+   definitions in jconfig.h header, but many users compile library in wrong
+   way. That causes errors of the following type:
+
+   "JPEGLib: JPEG parameter struct mismatch: library thinks size is 432,
+   caller expects 464"
+
+   For such users we wil fix the problem here. See install.doc file from
+   the JPEG library distribution for details.
+*/
+
+/* Define "boolean" as unsigned char, not int, per Windows custom. */
+#if defined(WIN32) && !defined(__MINGW32__)
+# ifndef __RPCNDR_H__            /* don't conflict if rpcndr.h already read */
+   typedef unsigned char boolean;
+# endif
+# define HAVE_BOOLEAN            /* prevent jmorecfg.h from redefining it */
+#endif
+
+#include "jpeglib.h"
+#include "jerror.h"
+
+/*
+ * We are using width_in_blocks which is supposed to be private to
+ * libjpeg. Unfortunately, the libjpeg delivered with Cygwin has
+ * renamed this member to width_in_data_units.  Since the header has
+ * also renamed a define, use that unique define name in order to
+ * detect the problem header and adjust to suit.
+ */
+#if defined(D_MAX_DATA_UNITS_IN_MCU)
+#define width_in_blocks width_in_data_units
+#endif
+
+/*
+ * On some machines it may be worthwhile to use _setjmp or sigsetjmp
+ * in place of plain setjmp.  These macros will make it easier.
+ */
+#define SETJMP(jbuf)		setjmp(jbuf)
+#define LONGJMP(jbuf,code)	longjmp(jbuf,code)
+#define JMP_BUF			jmp_buf
+
+typedef struct jpeg_destination_mgr jpeg_destination_mgr;
+typedef struct jpeg_source_mgr jpeg_source_mgr;
+typedef	struct jpeg_error_mgr jpeg_error_mgr;
+
+/*
+ * State block for each open TIFF file using
+ * libjpeg to do JPEG compression/decompression.
+ *
+ * libjpeg's visible state is either a jpeg_compress_struct
+ * or jpeg_decompress_struct depending on which way we
+ * are going.  comm can be used to refer to the fields
+ * which are common to both.
+ *
+ * NB: cinfo is required to be the first member of JPEGState,
+ *     so we can safely cast JPEGState* -> jpeg_xxx_struct*
+ *     and vice versa!
+ */
+typedef	struct {
+	union {
+		struct jpeg_compress_struct c;
+		struct jpeg_decompress_struct d;
+		struct jpeg_common_struct comm;
+	} cinfo;			/* NB: must be first */
+        int             cinfo_initialized;
+
+	jpeg_error_mgr	err;		/* libjpeg error manager */
+	JMP_BUF		exit_jmpbuf;	/* for catching libjpeg failures */
+	/*
+	 * The following two members could be a union, but
+	 * they're small enough that it's not worth the effort.
+	 */
+	jpeg_destination_mgr dest;	/* data dest for compression */
+	jpeg_source_mgr	src;		/* data source for decompression */
+					/* private state */
+	TIFF*		tif;		/* back link needed by some code */
+	uint16		photometric;	/* copy of PhotometricInterpretation */
+	uint16		h_sampling;	/* luminance sampling factors */
+	uint16		v_sampling;
+	tsize_t		bytesperline;	/* decompressed bytes per scanline */
+	/* pointers to intermediate buffers when processing downsampled data */
+	JSAMPARRAY	ds_buffer[MAX_COMPONENTS];
+	int		scancount;	/* number of "scanlines" accumulated */
+	int		samplesperclump;
+
+	TIFFVGetMethod	vgetparent;	/* super-class method */
+	TIFFVSetMethod	vsetparent;	/* super-class method */
+	TIFFPrintMethod printdir;	/* super-class method */
+	TIFFStripMethod	defsparent;	/* super-class method */
+	TIFFTileMethod	deftparent;	/* super-class method */
+					/* pseudo-tag fields */
+	void*		jpegtables;	/* JPEGTables tag value, or NULL */
+	uint32		jpegtables_length; /* number of bytes in same */
+	int		jpegquality;	/* Compression quality level */
+	int		jpegcolormode;	/* Auto RGB<=>YCbCr convert? */
+	int		jpegtablesmode;	/* What to put in JPEGTables */
+
+        int             ycbcrsampling_fetched;
+	uint32		recvparams;	/* encoded Class 2 session params */
+	char*		subaddress;	/* subaddress string */
+	uint32		recvtime;	/* time spent receiving (secs) */
+	char*		faxdcs;		/* encoded fax parameters (DCS, Table 2/T.30) */
+} JPEGState;
+
+#define	JState(tif)	((JPEGState*)(tif)->tif_data)
+
+static	int JPEGDecode(TIFF*, tidata_t, tsize_t, tsample_t);
+static	int JPEGDecodeRaw(TIFF*, tidata_t, tsize_t, tsample_t);
+static	int JPEGEncode(TIFF*, tidata_t, tsize_t, tsample_t);
+static	int JPEGEncodeRaw(TIFF*, tidata_t, tsize_t, tsample_t);
+static  int JPEGInitializeLibJPEG( TIFF * tif,
+								   int force_encode, int force_decode );
+
+#define	FIELD_JPEGTABLES	(FIELD_CODEC+0)
+#define	FIELD_RECVPARAMS	(FIELD_CODEC+1)
+#define	FIELD_SUBADDRESS	(FIELD_CODEC+2)
+#define	FIELD_RECVTIME		(FIELD_CODEC+3)
+#define	FIELD_FAXDCS		(FIELD_CODEC+4)
+
+static const TIFFFieldInfo jpegFieldInfo[] = {
+    { TIFFTAG_JPEGTABLES,	 -3,-3,	TIFF_UNDEFINED,	FIELD_JPEGTABLES,
+      FALSE,	TRUE,	"JPEGTables" },
+    { TIFFTAG_JPEGQUALITY,	 0, 0,	TIFF_ANY,	FIELD_PSEUDO,
+      TRUE,	FALSE,	"" },
+    { TIFFTAG_JPEGCOLORMODE,	 0, 0,	TIFF_ANY,	FIELD_PSEUDO,
+      FALSE,	FALSE,	"" },
+    { TIFFTAG_JPEGTABLESMODE,	 0, 0,	TIFF_ANY,	FIELD_PSEUDO,
+      FALSE,	FALSE,	"" },
+    /* Specific for JPEG in faxes */
+    { TIFFTAG_FAXRECVPARAMS,	 1, 1, TIFF_LONG,	FIELD_RECVPARAMS,
+      TRUE,	FALSE,	"FaxRecvParams" },
+    { TIFFTAG_FAXSUBADDRESS,	-1,-1, TIFF_ASCII,	FIELD_SUBADDRESS,
+      TRUE,	FALSE,	"FaxSubAddress" },
+    { TIFFTAG_FAXRECVTIME,	 1, 1, TIFF_LONG,	FIELD_RECVTIME,
+      TRUE,	FALSE,	"FaxRecvTime" },
+    { TIFFTAG_FAXDCS,		-1, -1, TIFF_ASCII,	FIELD_FAXDCS,
+	  TRUE,	FALSE,	"FaxDcs" },
+};
+#define	N(a)	(sizeof (a) / sizeof (a[0]))
+
+/*
+ * libjpeg interface layer.
+ *
+ * We use setjmp/longjmp to return control to libtiff
+ * when a fatal error is encountered within the JPEG
+ * library.  We also direct libjpeg error and warning
+ * messages through the appropriate libtiff handlers.
+ */
+
+/*
+ * Error handling routines (these replace corresponding
+ * IJG routines from jerror.c).  These are used for both
+ * compression and decompression.
+ */
+static void
+TIFFjpeg_error_exit(j_common_ptr cinfo)
+{
+	JPEGState *sp = (JPEGState *) cinfo;	/* NB: cinfo assumed first */
+	char buffer[JMSG_LENGTH_MAX];
+
+	(*cinfo->err->format_message) (cinfo, buffer);
+	TIFFErrorExt(sp->tif->tif_clientdata, "JPEGLib", "%s", buffer);		/* display the error message */
+	jpeg_abort(cinfo);			/* clean up libjpeg state */
+	LONGJMP(sp->exit_jmpbuf, 1);		/* return to libtiff caller */
+}
+
+/*
+ * This routine is invoked only for warning messages,
+ * since error_exit does its own thing and trace_level
+ * is never set > 0.
+ */
+static void
+TIFFjpeg_output_message(j_common_ptr cinfo)
+{
+	char buffer[JMSG_LENGTH_MAX];
+
+	(*cinfo->err->format_message) (cinfo, buffer);
+	TIFFWarningExt(((JPEGState *) cinfo)->tif->tif_clientdata, "JPEGLib", "%s", buffer);
+}
+
+/*
+ * Interface routines.  This layer of routines exists
+ * primarily to limit side-effects from using setjmp.
+ * Also, normal/error returns are converted into return
+ * values per libtiff practice.
+ */
+#define	CALLJPEG(sp, fail, op)	(SETJMP((sp)->exit_jmpbuf) ? (fail) : (op))
+#define	CALLVJPEG(sp, op)	CALLJPEG(sp, 0, ((op),1))
+
+static int
+TIFFjpeg_create_compress(JPEGState* sp)
+{
+	/* initialize JPEG error handling */
+	sp->cinfo.c.err = jpeg_std_error(&sp->err);
+	sp->err.error_exit = TIFFjpeg_error_exit;
+	sp->err.output_message = TIFFjpeg_output_message;
+
+	return CALLVJPEG(sp, jpeg_create_compress(&sp->cinfo.c));
+}
+
+static int
+TIFFjpeg_create_decompress(JPEGState* sp)
+{
+	/* initialize JPEG error handling */
+	sp->cinfo.d.err = jpeg_std_error(&sp->err);
+	sp->err.error_exit = TIFFjpeg_error_exit;
+	sp->err.output_message = TIFFjpeg_output_message;
+
+	return CALLVJPEG(sp, jpeg_create_decompress(&sp->cinfo.d));
+}
+
+static int
+TIFFjpeg_set_defaults(JPEGState* sp)
+{
+	return CALLVJPEG(sp, jpeg_set_defaults(&sp->cinfo.c));
+}
+
+static int
+TIFFjpeg_set_colorspace(JPEGState* sp, J_COLOR_SPACE colorspace)
+{
+	return CALLVJPEG(sp, jpeg_set_colorspace(&sp->cinfo.c, colorspace));
+}
+
+static int
+TIFFjpeg_set_quality(JPEGState* sp, int quality, boolean force_baseline)
+{
+	return CALLVJPEG(sp,
+	    jpeg_set_quality(&sp->cinfo.c, quality, force_baseline));
+}
+
+static int
+TIFFjpeg_suppress_tables(JPEGState* sp, boolean suppress)
+{
+	return CALLVJPEG(sp, jpeg_suppress_tables(&sp->cinfo.c, suppress));
+}
+
+static int
+TIFFjpeg_start_compress(JPEGState* sp, boolean write_all_tables)
+{
+	return CALLVJPEG(sp,
+	    jpeg_start_compress(&sp->cinfo.c, write_all_tables));
+}
+
+static int
+TIFFjpeg_write_scanlines(JPEGState* sp, JSAMPARRAY scanlines, int num_lines)
+{
+	return CALLJPEG(sp, -1, (int) jpeg_write_scanlines(&sp->cinfo.c,
+	    scanlines, (JDIMENSION) num_lines));
+}
+
+static int
+TIFFjpeg_write_raw_data(JPEGState* sp, JSAMPIMAGE data, int num_lines)
+{
+	return CALLJPEG(sp, -1, (int) jpeg_write_raw_data(&sp->cinfo.c,
+	    data, (JDIMENSION) num_lines));
+}
+
+static int
+TIFFjpeg_finish_compress(JPEGState* sp)
+{
+	return CALLVJPEG(sp, jpeg_finish_compress(&sp->cinfo.c));
+}
+
+static int
+TIFFjpeg_write_tables(JPEGState* sp)
+{
+	return CALLVJPEG(sp, jpeg_write_tables(&sp->cinfo.c));
+}
+
+static int
+TIFFjpeg_read_header(JPEGState* sp, boolean require_image)
+{
+	return CALLJPEG(sp, -1, jpeg_read_header(&sp->cinfo.d, require_image));
+}
+
+static int
+TIFFjpeg_start_decompress(JPEGState* sp)
+{
+	return CALLVJPEG(sp, jpeg_start_decompress(&sp->cinfo.d));
+}
+
+static int
+TIFFjpeg_read_scanlines(JPEGState* sp, JSAMPARRAY scanlines, int max_lines)
+{
+	return CALLJPEG(sp, -1, (int) jpeg_read_scanlines(&sp->cinfo.d,
+	    scanlines, (JDIMENSION) max_lines));
+}
+
+static int
+TIFFjpeg_read_raw_data(JPEGState* sp, JSAMPIMAGE data, int max_lines)
+{
+	return CALLJPEG(sp, -1, (int) jpeg_read_raw_data(&sp->cinfo.d,
+	    data, (JDIMENSION) max_lines));
+}
+
+static int
+TIFFjpeg_finish_decompress(JPEGState* sp)
+{
+	return CALLJPEG(sp, -1, (int) jpeg_finish_decompress(&sp->cinfo.d));
+}
+
+static int
+TIFFjpeg_abort(JPEGState* sp)
+{
+	return CALLVJPEG(sp, jpeg_abort(&sp->cinfo.comm));
+}
+
+static int
+TIFFjpeg_destroy(JPEGState* sp)
+{
+	return CALLVJPEG(sp, jpeg_destroy(&sp->cinfo.comm));
+}
+
+static JSAMPARRAY
+TIFFjpeg_alloc_sarray(JPEGState* sp, int pool_id,
+		      JDIMENSION samplesperrow, JDIMENSION numrows)
+{
+	return CALLJPEG(sp, (JSAMPARRAY) NULL,
+	    (*sp->cinfo.comm.mem->alloc_sarray)
+		(&sp->cinfo.comm, pool_id, samplesperrow, numrows));
+}
+
+/*
+ * JPEG library destination data manager.
+ * These routines direct compressed data from libjpeg into the
+ * libtiff output buffer.
+ */
+
+static void
+std_init_destination(j_compress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+	TIFF* tif = sp->tif;
+
+	sp->dest.next_output_byte = (JOCTET*) tif->tif_rawdata;
+	sp->dest.free_in_buffer = (size_t) tif->tif_rawdatasize;
+}
+
+static boolean
+std_empty_output_buffer(j_compress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+	TIFF* tif = sp->tif;
+
+	/* the entire buffer has been filled */
+	tif->tif_rawcc = tif->tif_rawdatasize;
+	TIFFFlushData1(tif);
+	sp->dest.next_output_byte = (JOCTET*) tif->tif_rawdata;
+	sp->dest.free_in_buffer = (size_t) tif->tif_rawdatasize;
+
+	return (TRUE);
+}
+
+static void
+std_term_destination(j_compress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+	TIFF* tif = sp->tif;
+
+	tif->tif_rawcp = (tidata_t) sp->dest.next_output_byte;
+	tif->tif_rawcc =
+	    tif->tif_rawdatasize - (tsize_t) sp->dest.free_in_buffer;
+	/* NB: libtiff does the final buffer flush */
+}
+
+static void
+TIFFjpeg_data_dest(JPEGState* sp, TIFF* tif)
+{
+	(void) tif;
+	sp->cinfo.c.dest = &sp->dest;
+	sp->dest.init_destination = std_init_destination;
+	sp->dest.empty_output_buffer = std_empty_output_buffer;
+	sp->dest.term_destination = std_term_destination;
+}
+
+/*
+ * Alternate destination manager for outputting to JPEGTables field.
+ */
+
+static void
+tables_init_destination(j_compress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+
+	/* while building, jpegtables_length is allocated buffer size */
+	sp->dest.next_output_byte = (JOCTET*) sp->jpegtables;
+	sp->dest.free_in_buffer = (size_t) sp->jpegtables_length;
+}
+
+static boolean
+tables_empty_output_buffer(j_compress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+	void* newbuf;
+
+	/* the entire buffer has been filled; enlarge it by 1000 bytes */
+	newbuf = _TIFFrealloc((tdata_t) sp->jpegtables,
+			      (tsize_t) (sp->jpegtables_length + 1000));
+	if (newbuf == NULL)
+		ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 100);
+	sp->dest.next_output_byte = (JOCTET*) newbuf + sp->jpegtables_length;
+	sp->dest.free_in_buffer = (size_t) 1000;
+	sp->jpegtables = newbuf;
+	sp->jpegtables_length += 1000;
+	return (TRUE);
+}
+
+static void
+tables_term_destination(j_compress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+
+	/* set tables length to number of bytes actually emitted */
+	sp->jpegtables_length -= sp->dest.free_in_buffer;
+}
+
+static int
+TIFFjpeg_tables_dest(JPEGState* sp, TIFF* tif)
+{
+	(void) tif;
+	/*
+	 * Allocate a working buffer for building tables.
+	 * Initial size is 1000 bytes, which is usually adequate.
+	 */
+	if (sp->jpegtables)
+		_TIFFfree(sp->jpegtables);
+	sp->jpegtables_length = 1000;
+	sp->jpegtables = (void*) _TIFFmalloc((tsize_t) sp->jpegtables_length);
+	if (sp->jpegtables == NULL) {
+		sp->jpegtables_length = 0;
+		TIFFErrorExt(sp->tif->tif_clientdata, "TIFFjpeg_tables_dest", "No space for JPEGTables");
+		return (0);
+	}
+	sp->cinfo.c.dest = &sp->dest;
+	sp->dest.init_destination = tables_init_destination;
+	sp->dest.empty_output_buffer = tables_empty_output_buffer;
+	sp->dest.term_destination = tables_term_destination;
+	return (1);
+}
+
+/*
+ * JPEG library source data manager.
+ * These routines supply compressed data to libjpeg.
+ */
+
+static void
+std_init_source(j_decompress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+	TIFF* tif = sp->tif;
+
+	sp->src.next_input_byte = (const JOCTET*) tif->tif_rawdata;
+	sp->src.bytes_in_buffer = (size_t) tif->tif_rawcc;
+}
+
+static boolean
+std_fill_input_buffer(j_decompress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState* ) cinfo;
+	static const JOCTET dummy_EOI[2] = { 0xFF, JPEG_EOI };
+
+	/*
+	 * Should never get here since entire strip/tile is
+	 * read into memory before the decompressor is called,
+	 * and thus was supplied by init_source.
+	 */
+	WARNMS(cinfo, JWRN_JPEG_EOF);
+	/* insert a fake EOI marker */
+	sp->src.next_input_byte = dummy_EOI;
+	sp->src.bytes_in_buffer = 2;
+	return (TRUE);
+}
+
+static void
+std_skip_input_data(j_decompress_ptr cinfo, long num_bytes)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+
+	if (num_bytes > 0) {
+		if (num_bytes > (long) sp->src.bytes_in_buffer) {
+			/* oops, buffer overrun */
+			(void) std_fill_input_buffer(cinfo);
+		} else {
+			sp->src.next_input_byte += (size_t) num_bytes;
+			sp->src.bytes_in_buffer -= (size_t) num_bytes;
+		}
+	}
+}
+
+static void
+std_term_source(j_decompress_ptr cinfo)
+{
+	/* No work necessary here */
+	/* Or must we update tif->tif_rawcp, tif->tif_rawcc ??? */
+	/* (if so, need empty tables_term_source!) */
+	(void) cinfo;
+}
+
+static void
+TIFFjpeg_data_src(JPEGState* sp, TIFF* tif)
+{
+	(void) tif;
+	sp->cinfo.d.src = &sp->src;
+	sp->src.init_source = std_init_source;
+	sp->src.fill_input_buffer = std_fill_input_buffer;
+	sp->src.skip_input_data = std_skip_input_data;
+	sp->src.resync_to_restart = jpeg_resync_to_restart;
+	sp->src.term_source = std_term_source;
+	sp->src.bytes_in_buffer = 0;		/* for safety */
+	sp->src.next_input_byte = NULL;
+}
+
+/*
+ * Alternate source manager for reading from JPEGTables.
+ * We can share all the code except for the init routine.
+ */
+
+static void
+tables_init_source(j_decompress_ptr cinfo)
+{
+	JPEGState* sp = (JPEGState*) cinfo;
+
+	sp->src.next_input_byte = (const JOCTET*) sp->jpegtables;
+	sp->src.bytes_in_buffer = (size_t) sp->jpegtables_length;
+}
+
+static void
+TIFFjpeg_tables_src(JPEGState* sp, TIFF* tif)
+{
+	TIFFjpeg_data_src(sp, tif);
+	sp->src.init_source = tables_init_source;
+}
+
+/*
+ * Allocate downsampled-data buffers needed for downsampled I/O.
+ * We use values computed in jpeg_start_compress or jpeg_start_decompress.
+ * We use libjpeg's allocator so that buffers will be released automatically
+ * when done with strip/tile.
+ * This is also a handy place to compute samplesperclump, bytesperline.
+ */
+static int
+alloc_downsampled_buffers(TIFF* tif, jpeg_component_info* comp_info,
+			  int num_components)
+{
+	JPEGState* sp = JState(tif);
+	int ci;
+	jpeg_component_info* compptr;
+	JSAMPARRAY buf;
+	int samples_per_clump = 0;
+
+	for (ci = 0, compptr = comp_info; ci < num_components;
+	     ci++, compptr++) {
+		samples_per_clump += compptr->h_samp_factor *
+			compptr->v_samp_factor;
+		buf = TIFFjpeg_alloc_sarray(sp, JPOOL_IMAGE,
+				compptr->width_in_blocks * DCTSIZE,
+				(JDIMENSION) (compptr->v_samp_factor*DCTSIZE));
+		if (buf == NULL)
+			return (0);
+		sp->ds_buffer[ci] = buf;
+	}
+	sp->samplesperclump = samples_per_clump;
+	return (1);
+}
+
+
+/*
+ * JPEG Decoding.
+ */
+
+static int
+JPEGSetupDecode(TIFF* tif)
+{
+	JPEGState* sp = JState(tif);
+	TIFFDirectory *td = &tif->tif_dir;
+
+        JPEGInitializeLibJPEG( tif, 0, 1 );
+
+	assert(sp != NULL);
+	assert(sp->cinfo.comm.is_decompressor);
+
+	/* Read JPEGTables if it is present */
+	if (TIFFFieldSet(tif,FIELD_JPEGTABLES)) {
+		TIFFjpeg_tables_src(sp, tif);
+		if(TIFFjpeg_read_header(sp,FALSE) != JPEG_HEADER_TABLES_ONLY) {
+			TIFFErrorExt(tif->tif_clientdata, "JPEGSetupDecode", "Bogus JPEGTables field");
+			return (0);
+		}
+	}
+
+	/* Grab parameters that are same for all strips/tiles */
+	sp->photometric = td->td_photometric;
+	switch (sp->photometric) {
+	case PHOTOMETRIC_YCBCR:
+		sp->h_sampling = td->td_ycbcrsubsampling[0];
+		sp->v_sampling = td->td_ycbcrsubsampling[1];
+		break;
+	default:
+		/* TIFF 6.0 forbids subsampling of all other color spaces */
+		sp->h_sampling = 1;
+		sp->v_sampling = 1;
+		break;
+	}
+
+	/* Set up for reading normal data */
+	TIFFjpeg_data_src(sp, tif);
+	tif->tif_postdecode = _TIFFNoPostDecode; /* override byte swapping */
+	return (1);
+}
+
+/*
+ * Set up for decoding a strip or tile.
+ */
+static int
+JPEGPreDecode(TIFF* tif, tsample_t s)
+{
+	JPEGState *sp = JState(tif);
+	TIFFDirectory *td = &tif->tif_dir;
+	static const char module[] = "JPEGPreDecode";
+	uint32 segment_width, segment_height;
+	int downsampled_output;
+	int ci;
+
+	assert(sp != NULL);
+	assert(sp->cinfo.comm.is_decompressor);
+	/*
+	 * Reset decoder state from any previous strip/tile,
+	 * in case application didn't read the whole strip.
+	 */
+	if (!TIFFjpeg_abort(sp))
+		return (0);
+	/*
+	 * Read the header for this strip/tile.
+	 */
+	if (TIFFjpeg_read_header(sp, TRUE) != JPEG_HEADER_OK)
+		return (0);
+	/*
+	 * Check image parameters and set decompression parameters.
+	 */
+	segment_width = td->td_imagewidth;
+	segment_height = td->td_imagelength - tif->tif_row;
+	if (isTiled(tif)) {
+                segment_width = td->td_tilewidth;
+                segment_height = td->td_tilelength;
+		sp->bytesperline = TIFFTileRowSize(tif);
+	} else {
+		if (segment_height > td->td_rowsperstrip)
+			segment_height = td->td_rowsperstrip;
+		sp->bytesperline = TIFFOldScanlineSize(tif);
+	}
+	if (td->td_planarconfig == PLANARCONFIG_SEPARATE && s > 0) {
+		/*
+		 * For PC 2, scale down the expected strip/tile size
+		 * to match a downsampled component
+		 */
+		segment_width = TIFFhowmany(segment_width, sp->h_sampling);
+		segment_height = TIFFhowmany(segment_height, sp->v_sampling);
+	}
+	if (sp->cinfo.d.image_width < segment_width ||
+	    sp->cinfo.d.image_height < segment_height) {
+		TIFFWarningExt(tif->tif_clientdata, module,
+			       "Improper JPEG strip/tile size, "
+			       "expected %dx%d, got %dx%d",
+			       segment_width, segment_height,
+			       sp->cinfo.d.image_width,
+			       sp->cinfo.d.image_height);
+	} 
+	if (sp->cinfo.d.image_width > segment_width ||
+	    sp->cinfo.d.image_height > segment_height) {
+		/*
+		 * This case could be dangerous, if the strip or tile size has
+		 * been reported as less than the amount of data jpeg will
+		 * return, some potential security issues arise. Catch this
+		 * case and error out.
+		 */
+		TIFFErrorExt(tif->tif_clientdata, module,
+			     "JPEG strip/tile size exceeds expected dimensions,"
+			     " expected %dx%d, got %dx%d",
+			     segment_width, segment_height,
+			     sp->cinfo.d.image_width, sp->cinfo.d.image_height);
+		return (0);
+	}
+	if (sp->cinfo.d.num_components !=
+	    (td->td_planarconfig == PLANARCONFIG_CONTIG ?
+	     td->td_samplesperpixel : 1)) {
+		TIFFErrorExt(tif->tif_clientdata, module, "Improper JPEG component count");
+		return (0);
+	}
+#ifdef JPEG_LIB_MK1
+	if (12 != td->td_bitspersample && 8 != td->td_bitspersample) {
+			TIFFErrorExt(tif->tif_clientdata, module, "Improper JPEG data precision");
+            return (0);
+	}
+        sp->cinfo.d.data_precision = td->td_bitspersample;
+        sp->cinfo.d.bits_in_jsample = td->td_bitspersample;
+#else
+	if (sp->cinfo.d.data_precision != td->td_bitspersample) {
+			TIFFErrorExt(tif->tif_clientdata, module, "Improper JPEG data precision");
+            return (0);
+	}
+#endif
+	if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
+		/* Component 0 should have expected sampling factors */
+		if (sp->cinfo.d.comp_info[0].h_samp_factor != sp->h_sampling ||
+		    sp->cinfo.d.comp_info[0].v_samp_factor != sp->v_sampling) {
+				TIFFWarningExt(tif->tif_clientdata, module,
+                                    "Improper JPEG sampling factors %d,%d\n"
+                                    "Apparently should be %d,%d.",
+                                    sp->cinfo.d.comp_info[0].h_samp_factor,
+                                    sp->cinfo.d.comp_info[0].v_samp_factor,
+                                    sp->h_sampling, sp->v_sampling);
+
+				/*
+				 * There are potential security issues here
+				 * for decoders that have already allocated
+				 * buffers based on the expected sampling
+				 * factors. Lets check the sampling factors
+				 * dont exceed what we were expecting.
+				 */
+				if (sp->cinfo.d.comp_info[0].h_samp_factor
+					> sp->h_sampling
+				    || sp->cinfo.d.comp_info[0].v_samp_factor
+					> sp->v_sampling) {
+					TIFFErrorExt(tif->tif_clientdata,
+						     module,
+					"Cannot honour JPEG sampling factors"
+					" that exceed those specified.");
+					return (0);
+				}
+
+			    /*
+			     * XXX: Files written by the Intergraph software
+			     * has different sampling factors stored in the
+			     * TIFF tags and in the JPEG structures. We will
+			     * try to deduce Intergraph files by the presense
+			     * of the tag 33918.
+			     */
+			    if (!_TIFFFindFieldInfo(tif, 33918, TIFF_ANY)) {
+					TIFFWarningExt(tif->tif_clientdata, module,
+					"Decompressor will try reading with "
+					"sampling %d,%d.",
+					sp->cinfo.d.comp_info[0].h_samp_factor,
+					sp->cinfo.d.comp_info[0].v_samp_factor);
+
+				    sp->h_sampling = (uint16)
+					sp->cinfo.d.comp_info[0].h_samp_factor;
+				    sp->v_sampling = (uint16)
+					sp->cinfo.d.comp_info[0].v_samp_factor;
+			    }
+		}
+		/* Rest should have sampling factors 1,1 */
+		for (ci = 1; ci < sp->cinfo.d.num_components; ci++) {
+			if (sp->cinfo.d.comp_info[ci].h_samp_factor != 1 ||
+			    sp->cinfo.d.comp_info[ci].v_samp_factor != 1) {
+				TIFFErrorExt(tif->tif_clientdata, module, "Improper JPEG sampling factors");
+				return (0);
+			}
+		}
+	} else {
+		/* PC 2's single component should have sampling factors 1,1 */
+		if (sp->cinfo.d.comp_info[0].h_samp_factor != 1 ||
+		    sp->cinfo.d.comp_info[0].v_samp_factor != 1) {
+			TIFFErrorExt(tif->tif_clientdata, module, "Improper JPEG sampling factors");
+			return (0);
+		}
+	}
+	downsampled_output = FALSE;
+	if (td->td_planarconfig == PLANARCONFIG_CONTIG &&
+	    sp->photometric == PHOTOMETRIC_YCBCR &&
+	    sp->jpegcolormode == JPEGCOLORMODE_RGB) {
+	/* Convert YCbCr to RGB */
+		sp->cinfo.d.jpeg_color_space = JCS_YCbCr;
+		sp->cinfo.d.out_color_space = JCS_RGB;
+	} else {
+			/* Suppress colorspace handling */
+		sp->cinfo.d.jpeg_color_space = JCS_UNKNOWN;
+		sp->cinfo.d.out_color_space = JCS_UNKNOWN;
+		if (td->td_planarconfig == PLANARCONFIG_CONTIG &&
+		    (sp->h_sampling != 1 || sp->v_sampling != 1))
+			downsampled_output = TRUE;
+		/* XXX what about up-sampling? */
+	}
+	if (downsampled_output) {
+		/* Need to use raw-data interface to libjpeg */
+		sp->cinfo.d.raw_data_out = TRUE;
+		tif->tif_decoderow = JPEGDecodeRaw;
+		tif->tif_decodestrip = JPEGDecodeRaw;
+		tif->tif_decodetile = JPEGDecodeRaw;
+	} else {
+		/* Use normal interface to libjpeg */
+		sp->cinfo.d.raw_data_out = FALSE;
+		tif->tif_decoderow = JPEGDecode;
+		tif->tif_decodestrip = JPEGDecode;
+		tif->tif_decodetile = JPEGDecode;
+	}
+	/* Start JPEG decompressor */
+	if (!TIFFjpeg_start_decompress(sp))
+		return (0);
+	/* Allocate downsampled-data buffers if needed */
+	if (downsampled_output) {
+		if (!alloc_downsampled_buffers(tif, sp->cinfo.d.comp_info,
+					       sp->cinfo.d.num_components))
+			return (0);
+		sp->scancount = DCTSIZE;	/* mark buffer empty */
+	}
+	return (1);
+}
+
+/*
+ * Decode a chunk of pixels.
+ * "Standard" case: returned data is not downsampled.
+ */
+/*ARGSUSED*/ static int
+JPEGDecode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
+{
+    JPEGState *sp = JState(tif);
+    tsize_t nrows;
+    (void) s;
+
+    nrows = cc / sp->bytesperline;
+    if (cc % sp->bytesperline)
+		TIFFWarningExt(tif->tif_clientdata, tif->tif_name, "fractional scanline not read");
+
+    if( nrows > (int) sp->cinfo.d.image_height )
+        nrows = sp->cinfo.d.image_height;
+
+    /* data is expected to be read in multiples of a scanline */
+    if (nrows)
+    {
+        JSAMPROW line_work_buf = NULL;
+
+        /*
+        ** For 6B, only use temporary buffer for 12 bit imagery. 
+        ** For Mk1 always use it. 
+        */
+#if !defined(JPEG_LIB_MK1)        
+        if( sp->cinfo.d.data_precision == 12 )
+#endif
+        {
+            line_work_buf = (JSAMPROW) 
+                _TIFFmalloc(sizeof(short) * sp->cinfo.d.output_width 
+                            * sp->cinfo.d.num_components );
+        }
+
+        do {
+            if( line_work_buf != NULL )
+            {
+                /* 
+                ** In the MK1 case, we aways read into a 16bit buffer, and then
+                ** pack down to 12bit or 8bit.  In 6B case we only read into 16
+                ** bit buffer for 12bit data, which we need to repack. 
+                */
+                if (TIFFjpeg_read_scanlines(sp, &line_work_buf, 1) != 1)
+                    return (0);
+
+                if( sp->cinfo.d.data_precision == 12 )
+                {
+                    int value_pairs = (sp->cinfo.d.output_width 
+                                       * sp->cinfo.d.num_components) / 2;
+                    int iPair;
+
+                    for( iPair = 0; iPair < value_pairs; iPair++ )
+                    {
+                        unsigned char *out_ptr = 
+                            ((unsigned char *) buf) + iPair * 3;
+                        JSAMPLE *in_ptr = line_work_buf + iPair * 2;
+
+                        out_ptr[0] = (in_ptr[0] & 0xff0) >> 4;
+                        out_ptr[1] = ((in_ptr[0] & 0xf) << 4)
+                            | ((in_ptr[1] & 0xf00) >> 8);
+                        out_ptr[2] = ((in_ptr[1] & 0xff) >> 0);
+                    }
+                }
+                else if( sp->cinfo.d.data_precision == 8 )
+                {
+                    int value_count = (sp->cinfo.d.output_width 
+                                       * sp->cinfo.d.num_components);
+                    int iValue;
+
+                    for( iValue = 0; iValue < value_count; iValue++ )
+                    {
+                        ((unsigned char *) buf)[iValue] = 
+                            line_work_buf[iValue] & 0xff;
+                    }
+                }
+            }
+            else
+            {
+                /*
+                ** In the libjpeg6b 8bit case.  We read directly into the 
+                ** TIFF buffer.
+                */
+                JSAMPROW bufptr = (JSAMPROW)buf;
+  
+                if (TIFFjpeg_read_scanlines(sp, &bufptr, 1) != 1)
+                    return (0);
+            }
+
+            ++tif->tif_row;
+            buf += sp->bytesperline;
+            cc -= sp->bytesperline;
+        } while (--nrows > 0);
+
+        if( line_work_buf != NULL )
+            _TIFFfree( line_work_buf );
+    }
+
+    /* Close down the decompressor if we've finished the strip or tile. */
+    return sp->cinfo.d.output_scanline < sp->cinfo.d.output_height
+        || TIFFjpeg_finish_decompress(sp);
+}
+
+/*
+ * Decode a chunk of pixels.
+ * Returned data is downsampled per sampling factors.
+ */
+/*ARGSUSED*/ static int
+JPEGDecodeRaw(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
+{
+	JPEGState *sp = JState(tif);
+	tsize_t nrows;
+	(void) s;
+
+	/* data is expected to be read in multiples of a scanline */
+	if ( (nrows = sp->cinfo.d.image_height) ) {
+		/* Cb,Cr both have sampling factors 1, so this is correct */
+		JDIMENSION clumps_per_line = sp->cinfo.d.comp_info[1].downsampled_width;            
+		int samples_per_clump = sp->samplesperclump;
+
+#ifdef JPEG_LIB_MK1
+		unsigned short* tmpbuf = _TIFFmalloc(sizeof(unsigned short) *
+		    sp->cinfo.d.output_width *
+		    sp->cinfo.d.num_components);
+#endif
+
+		do {
+			jpeg_component_info *compptr;
+			int ci, clumpoffset;
+
+			/* Reload downsampled-data buffer if needed */
+			if (sp->scancount >= DCTSIZE) {
+				int n = sp->cinfo.d.max_v_samp_factor * DCTSIZE;
+				if (TIFFjpeg_read_raw_data(sp, sp->ds_buffer, n) != n)
+					return (0);
+				sp->scancount = 0;
+			}
+			/*
+			 * Fastest way to unseparate data is to make one pass
+			 * over the scanline for each row of each component.
+			 */
+			clumpoffset = 0;    /* first sample in clump */
+			for (ci = 0, compptr = sp->cinfo.d.comp_info;
+			    ci < sp->cinfo.d.num_components;
+			    ci++, compptr++) {
+				int hsamp = compptr->h_samp_factor;
+				int vsamp = compptr->v_samp_factor;
+				int ypos;
+
+				for (ypos = 0; ypos < vsamp; ypos++) {
+					JSAMPLE *inptr = sp->ds_buffer[ci][sp->scancount*vsamp + ypos];
+#ifdef JPEG_LIB_MK1
+					JSAMPLE *outptr = (JSAMPLE*)tmpbuf + clumpoffset;
+#else
+					JSAMPLE *outptr = (JSAMPLE*)buf + clumpoffset;
+#endif
+					JDIMENSION nclump;
+
+					if (hsamp == 1) {
+						/* fast path for at least Cb and Cr */
+						for (nclump = clumps_per_line; nclump-- > 0; ) {
+							outptr[0] = *inptr++;
+							outptr += samples_per_clump;
+						}
+					} else {
+						int xpos;
+
+			/* general case */
+						for (nclump = clumps_per_line; nclump-- > 0; ) {
+							for (xpos = 0; xpos < hsamp; xpos++)
+								outptr[xpos] = *inptr++;
+							outptr += samples_per_clump;
+						}
+					}
+					clumpoffset += hsamp;
+				}
+			}
+
+#ifdef JPEG_LIB_MK1
+			{
+				if (sp->cinfo.d.data_precision == 8)
+				{
+					int i=0;
+					int len = sp->cinfo.d.output_width * sp->cinfo.d.num_components;
+					for (i=0; i<len; i++)
+					{
+						((unsigned char*)buf)[i] = tmpbuf[i] & 0xff;
+					}
+				}
+				else
+				{         // 12-bit
+					int value_pairs = (sp->cinfo.d.output_width
+					    * sp->cinfo.d.num_components) / 2;
+					int iPair;
+					for( iPair = 0; iPair < value_pairs; iPair++ )
+					{
+						unsigned char *out_ptr = ((unsigned char *) buf) + iPair * 3;
+						JSAMPLE *in_ptr = tmpbuf + iPair * 2;
+						out_ptr[0] = (in_ptr[0] & 0xff0) >> 4;
+						out_ptr[1] = ((in_ptr[0] & 0xf) << 4)
+						    | ((in_ptr[1] & 0xf00) >> 8);
+						out_ptr[2] = ((in_ptr[1] & 0xff) >> 0);
+					}
+				}
+			}
+#endif
+
+			sp->scancount ++;
+			tif->tif_row += sp->v_sampling;
+			/* increment/decrement of buf and cc is still incorrect, but should not matter
+			 * TODO: resolve this */
+			buf += sp->bytesperline;
+			cc -= sp->bytesperline;
+			nrows -= sp->v_sampling;
+		} while (nrows > 0);
+
+#ifdef JPEG_LIB_MK1
+		_TIFFfree(tmpbuf);
+#endif
+
+	}
+
+	/* Close down the decompressor if done. */
+	return sp->cinfo.d.output_scanline < sp->cinfo.d.output_height
+	    || TIFFjpeg_finish_decompress(sp);
+}
+
+
+/*
+ * JPEG Encoding.
+ */
+
+static void
+unsuppress_quant_table (JPEGState* sp, int tblno)
+{
+	JQUANT_TBL* qtbl;
+
+	if ((qtbl = sp->cinfo.c.quant_tbl_ptrs[tblno]) != NULL)
+		qtbl->sent_table = FALSE;
+}
+
+static void
+unsuppress_huff_table (JPEGState* sp, int tblno)
+{
+	JHUFF_TBL* htbl;
+
+	if ((htbl = sp->cinfo.c.dc_huff_tbl_ptrs[tblno]) != NULL)
+		htbl->sent_table = FALSE;
+	if ((htbl = sp->cinfo.c.ac_huff_tbl_ptrs[tblno]) != NULL)
+		htbl->sent_table = FALSE;
+}
+
+static int
+prepare_JPEGTables(TIFF* tif)
+{
+	JPEGState* sp = JState(tif);
+
+        JPEGInitializeLibJPEG( tif, 0, 0 );
+
+	/* Initialize quant tables for current quality setting */
+	if (!TIFFjpeg_set_quality(sp, sp->jpegquality, FALSE))
+		return (0);
+	/* Mark only the tables we want for output */
+	/* NB: chrominance tables are currently used only with YCbCr */
+	if (!TIFFjpeg_suppress_tables(sp, TRUE))
+		return (0);
+	if (sp->jpegtablesmode & JPEGTABLESMODE_QUANT) {
+		unsuppress_quant_table(sp, 0);
+		if (sp->photometric == PHOTOMETRIC_YCBCR)
+			unsuppress_quant_table(sp, 1);
+	}
+	if (sp->jpegtablesmode & JPEGTABLESMODE_HUFF) {
+		unsuppress_huff_table(sp, 0);
+		if (sp->photometric == PHOTOMETRIC_YCBCR)
+			unsuppress_huff_table(sp, 1);
+	}
+	/* Direct libjpeg output into jpegtables */
+	if (!TIFFjpeg_tables_dest(sp, tif))
+		return (0);
+	/* Emit tables-only datastream */
+	if (!TIFFjpeg_write_tables(sp))
+		return (0);
+
+	return (1);
+}
+
+static int
+JPEGSetupEncode(TIFF* tif)
+{
+	JPEGState* sp = JState(tif);
+	TIFFDirectory *td = &tif->tif_dir;
+	static const char module[] = "JPEGSetupEncode";
+
+        JPEGInitializeLibJPEG( tif, 1, 0 );
+
+	assert(sp != NULL);
+	assert(!sp->cinfo.comm.is_decompressor);
+
+	/*
+	 * Initialize all JPEG parameters to default values.
+	 * Note that jpeg_set_defaults needs legal values for
+	 * in_color_space and input_components.
+	 */
+	sp->cinfo.c.in_color_space = JCS_UNKNOWN;
+	sp->cinfo.c.input_components = 1;
+	if (!TIFFjpeg_set_defaults(sp))
+		return (0);
+	/* Set per-file parameters */
+	sp->photometric = td->td_photometric;
+	switch (sp->photometric) {
+	case PHOTOMETRIC_YCBCR:
+		sp->h_sampling = td->td_ycbcrsubsampling[0];
+		sp->v_sampling = td->td_ycbcrsubsampling[1];
+		/*
+		 * A ReferenceBlackWhite field *must* be present since the
+		 * default value is inappropriate for YCbCr.  Fill in the
+		 * proper value if application didn't set it.
+		 */
+		{
+			float *ref;
+			if (!TIFFGetField(tif, TIFFTAG_REFERENCEBLACKWHITE,
+					  &ref)) {
+				float refbw[6];
+				long top = 1L << td->td_bitspersample;
+				refbw[0] = 0;
+				refbw[1] = (float)(top-1L);
+				refbw[2] = (float)(top>>1);
+				refbw[3] = refbw[1];
+				refbw[4] = refbw[2];
+				refbw[5] = refbw[1];
+				TIFFSetField(tif, TIFFTAG_REFERENCEBLACKWHITE,
+					     refbw);
+			}
+		}
+		break;
+	case PHOTOMETRIC_PALETTE:		/* disallowed by Tech Note */
+	case PHOTOMETRIC_MASK:
+		TIFFErrorExt(tif->tif_clientdata, module,
+			  "PhotometricInterpretation %d not allowed for JPEG",
+			  (int) sp->photometric);
+		return (0);
+	default:
+		/* TIFF 6.0 forbids subsampling of all other color spaces */
+		sp->h_sampling = 1;
+		sp->v_sampling = 1;
+		break;
+	}
+
+	/* Verify miscellaneous parameters */
+
+	/*
+	 * This would need work if libtiff ever supports different
+	 * depths for different components, or if libjpeg ever supports
+	 * run-time selection of depth.  Neither is imminent.
+	 */
+#ifdef JPEG_LIB_MK1
+        /* BITS_IN_JSAMPLE now permits 8 and 12 --- dgilbert */
+	if (td->td_bitspersample != 8 && td->td_bitspersample != 12) 
+#else
+	if (td->td_bitspersample != BITS_IN_JSAMPLE )
+#endif
+	{
+		TIFFErrorExt(tif->tif_clientdata, module, "BitsPerSample %d not allowed for JPEG",
+			  (int) td->td_bitspersample);
+		return (0);
+	}
+	sp->cinfo.c.data_precision = td->td_bitspersample;
+#ifdef JPEG_LIB_MK1
+        sp->cinfo.c.bits_in_jsample = td->td_bitspersample;
+#endif
+	if (isTiled(tif)) {
+		if ((td->td_tilelength % (sp->v_sampling * DCTSIZE)) != 0) {
+			TIFFErrorExt(tif->tif_clientdata, module,
+				  "JPEG tile height must be multiple of %d",
+				  sp->v_sampling * DCTSIZE);
+			return (0);
+		}
+		if ((td->td_tilewidth % (sp->h_sampling * DCTSIZE)) != 0) {
+			TIFFErrorExt(tif->tif_clientdata, module,
+				  "JPEG tile width must be multiple of %d",
+				  sp->h_sampling * DCTSIZE);
+			return (0);
+		}
+	} else {
+		if (td->td_rowsperstrip < td->td_imagelength &&
+		    (td->td_rowsperstrip % (sp->v_sampling * DCTSIZE)) != 0) {
+			TIFFErrorExt(tif->tif_clientdata, module,
+				  "RowsPerStrip must be multiple of %d for JPEG",
+				  sp->v_sampling * DCTSIZE);
+			return (0);
+		}
+	}
+
+	/* Create a JPEGTables field if appropriate */
+	if (sp->jpegtablesmode & (JPEGTABLESMODE_QUANT|JPEGTABLESMODE_HUFF)) {
+		if (!prepare_JPEGTables(tif))
+			return (0);
+		/* Mark the field present */
+		/* Can't use TIFFSetField since BEENWRITING is already set! */
+		TIFFSetFieldBit(tif, FIELD_JPEGTABLES);
+		tif->tif_flags |= TIFF_DIRTYDIRECT;
+	} else {
+		/* We do not support application-supplied JPEGTables, */
+		/* so mark the field not present */
+		TIFFClrFieldBit(tif, FIELD_JPEGTABLES);
+	}
+
+	/* Direct libjpeg output to libtiff's output buffer */
+	TIFFjpeg_data_dest(sp, tif);
+
+	return (1);
+}
+
+/*
+ * Set encoding state at the start of a strip or tile.
+ */
+static int
+JPEGPreEncode(TIFF* tif, tsample_t s)
+{
+	JPEGState *sp = JState(tif);
+	TIFFDirectory *td = &tif->tif_dir;
+	static const char module[] = "JPEGPreEncode";
+	uint32 segment_width, segment_height;
+	int downsampled_input;
+
+	assert(sp != NULL);
+	assert(!sp->cinfo.comm.is_decompressor);
+	/*
+	 * Set encoding parameters for this strip/tile.
+	 */
+	if (isTiled(tif)) {
+		segment_width = td->td_tilewidth;
+		segment_height = td->td_tilelength;
+		sp->bytesperline = TIFFTileRowSize(tif);
+	} else {
+		segment_width = td->td_imagewidth;
+		segment_height = td->td_imagelength - tif->tif_row;
+		if (segment_height > td->td_rowsperstrip)
+			segment_height = td->td_rowsperstrip;
+		sp->bytesperline = TIFFOldScanlineSize(tif);
+	}
+	if (td->td_planarconfig == PLANARCONFIG_SEPARATE && s > 0) {
+		/* for PC 2, scale down the strip/tile size
+		 * to match a downsampled component
+		 */
+		segment_width = TIFFhowmany(segment_width, sp->h_sampling);
+		segment_height = TIFFhowmany(segment_height, sp->v_sampling);
+	}
+	if (segment_width > 65535 || segment_height > 65535) {
+		TIFFErrorExt(tif->tif_clientdata, module, "Strip/tile too large for JPEG");
+		return (0);
+	}
+	sp->cinfo.c.image_width = segment_width;
+	sp->cinfo.c.image_height = segment_height;
+	downsampled_input = FALSE;
+	if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
+		sp->cinfo.c.input_components = td->td_samplesperpixel;
+		if (sp->photometric == PHOTOMETRIC_YCBCR) {
+			if (sp->jpegcolormode == JPEGCOLORMODE_RGB) {
+				sp->cinfo.c.in_color_space = JCS_RGB;
+			} else {
+				sp->cinfo.c.in_color_space = JCS_YCbCr;
+				if (sp->h_sampling != 1 || sp->v_sampling != 1)
+					downsampled_input = TRUE;
+			}
+			if (!TIFFjpeg_set_colorspace(sp, JCS_YCbCr))
+				return (0);
+			/*
+			 * Set Y sampling factors;
+			 * we assume jpeg_set_colorspace() set the rest to 1
+			 */
+			sp->cinfo.c.comp_info[0].h_samp_factor = sp->h_sampling;
+			sp->cinfo.c.comp_info[0].v_samp_factor = sp->v_sampling;
+		} else {
+			sp->cinfo.c.in_color_space = JCS_UNKNOWN;
+			if (!TIFFjpeg_set_colorspace(sp, JCS_UNKNOWN))
+				return (0);
+			/* jpeg_set_colorspace set all sampling factors to 1 */
+		}
+	} else {
+		sp->cinfo.c.input_components = 1;
+		sp->cinfo.c.in_color_space = JCS_UNKNOWN;
+		if (!TIFFjpeg_set_colorspace(sp, JCS_UNKNOWN))
+			return (0);
+		sp->cinfo.c.comp_info[0].component_id = s;
+		/* jpeg_set_colorspace() set sampling factors to 1 */
+		if (sp->photometric == PHOTOMETRIC_YCBCR && s > 0) {
+			sp->cinfo.c.comp_info[0].quant_tbl_no = 1;
+			sp->cinfo.c.comp_info[0].dc_tbl_no = 1;
+			sp->cinfo.c.comp_info[0].ac_tbl_no = 1;
+		}
+	}
+	/* ensure libjpeg won't write any extraneous markers */
+	sp->cinfo.c.write_JFIF_header = FALSE;
+	sp->cinfo.c.write_Adobe_marker = FALSE;
+	/* set up table handling correctly */
+	if (! (sp->jpegtablesmode & JPEGTABLESMODE_QUANT)) {
+		if (!TIFFjpeg_set_quality(sp, sp->jpegquality, FALSE))
+			return (0);
+		unsuppress_quant_table(sp, 0);
+		unsuppress_quant_table(sp, 1);
+	}
+	if (sp->jpegtablesmode & JPEGTABLESMODE_HUFF)
+		sp->cinfo.c.optimize_coding = FALSE;
+	else
+		sp->cinfo.c.optimize_coding = TRUE;
+	if (downsampled_input) {
+		/* Need to use raw-data interface to libjpeg */
+		sp->cinfo.c.raw_data_in = TRUE;
+		tif->tif_encoderow = JPEGEncodeRaw;
+		tif->tif_encodestrip = JPEGEncodeRaw;
+		tif->tif_encodetile = JPEGEncodeRaw;
+	} else {
+		/* Use normal interface to libjpeg */
+		sp->cinfo.c.raw_data_in = FALSE;
+		tif->tif_encoderow = JPEGEncode;
+		tif->tif_encodestrip = JPEGEncode;
+		tif->tif_encodetile = JPEGEncode;
+	}
+	/* Start JPEG compressor */
+	if (!TIFFjpeg_start_compress(sp, FALSE))
+		return (0);
+	/* Allocate downsampled-data buffers if needed */
+	if (downsampled_input) {
+		if (!alloc_downsampled_buffers(tif, sp->cinfo.c.comp_info,
+					       sp->cinfo.c.num_components))
+			return (0);
+	}
+	sp->scancount = 0;
+
+	return (1);
+}
+
+/*
+ * Encode a chunk of pixels.
+ * "Standard" case: incoming data is not downsampled.
+ */
+static int
+JPEGEncode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
+{
+	JPEGState *sp = JState(tif);
+	tsize_t nrows;
+	JSAMPROW bufptr[1];
+
+	(void) s;
+	assert(sp != NULL);
+	/* data is expected to be supplied in multiples of a scanline */
+	nrows = cc / sp->bytesperline;
+	if (cc % sp->bytesperline)
+		TIFFWarningExt(tif->tif_clientdata, tif->tif_name, "fractional scanline discarded");
+
+        /* The last strip will be limited to image size */
+        if( !isTiled(tif) && tif->tif_row+nrows > tif->tif_dir.td_imagelength )
+            nrows = tif->tif_dir.td_imagelength - tif->tif_row;
+
+	while (nrows-- > 0) {
+		bufptr[0] = (JSAMPROW) buf;
+		if (TIFFjpeg_write_scanlines(sp, bufptr, 1) != 1)
+			return (0);
+		if (nrows > 0)
+			tif->tif_row++;
+		buf += sp->bytesperline;
+	}
+	return (1);
+}
+
+/*
+ * Encode a chunk of pixels.
+ * Incoming data is expected to be downsampled per sampling factors.
+ */
+static int
+JPEGEncodeRaw(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
+{
+	JPEGState *sp = JState(tif);
+	JSAMPLE* inptr;
+	JSAMPLE* outptr;
+	tsize_t nrows;
+	JDIMENSION clumps_per_line, nclump;
+	int clumpoffset, ci, xpos, ypos;
+	jpeg_component_info* compptr;
+	int samples_per_clump = sp->samplesperclump;
+	tsize_t bytesperclumpline;
+
+	(void) s;
+	assert(sp != NULL);
+	/* data is expected to be supplied in multiples of a clumpline */
+	/* a clumpline is equivalent to v_sampling desubsampled scanlines */
+	/* TODO: the following calculation of bytesperclumpline, should substitute calculation of sp->bytesperline, except that it is per v_sampling lines */
+	bytesperclumpline = (((sp->cinfo.c.image_width+sp->h_sampling-1)/sp->h_sampling)
+			     *(sp->h_sampling*sp->v_sampling+2)*sp->cinfo.c.data_precision+7)
+			    /8;
+
+	nrows = ( cc / bytesperclumpline ) * sp->v_sampling;
+	if (cc % bytesperclumpline)
+		TIFFWarningExt(tif->tif_clientdata, tif->tif_name, "fractional scanline discarded");
+
+	/* Cb,Cr both have sampling factors 1, so this is correct */
+	clumps_per_line = sp->cinfo.c.comp_info[1].downsampled_width;
+
+	while (nrows > 0) {
+		/*
+		 * Fastest way to separate the data is to make one pass
+		 * over the scanline for each row of each component.
+		 */
+		clumpoffset = 0;		/* first sample in clump */
+		for (ci = 0, compptr = sp->cinfo.c.comp_info;
+		     ci < sp->cinfo.c.num_components;
+		     ci++, compptr++) {
+		    int hsamp = compptr->h_samp_factor;
+		    int vsamp = compptr->v_samp_factor;
+		    int padding = (int) (compptr->width_in_blocks * DCTSIZE -
+					 clumps_per_line * hsamp);
+		    for (ypos = 0; ypos < vsamp; ypos++) {
+			inptr = ((JSAMPLE*) buf) + clumpoffset;
+			outptr = sp->ds_buffer[ci][sp->scancount*vsamp + ypos];
+			if (hsamp == 1) {
+			    /* fast path for at least Cb and Cr */
+			    for (nclump = clumps_per_line; nclump-- > 0; ) {
+				*outptr++ = inptr[0];
+				inptr += samples_per_clump;
+			    }
+			} else {
+			    /* general case */
+			    for (nclump = clumps_per_line; nclump-- > 0; ) {
+				for (xpos = 0; xpos < hsamp; xpos++)
+				    *outptr++ = inptr[xpos];
+				inptr += samples_per_clump;
+			    }
+			}
+			/* pad each scanline as needed */
+			for (xpos = 0; xpos < padding; xpos++) {
+			    *outptr = outptr[-1];
+			    outptr++;
+			}
+			clumpoffset += hsamp;
+		    }
+		}
+		sp->scancount++;
+		if (sp->scancount >= DCTSIZE) {
+			int n = sp->cinfo.c.max_v_samp_factor * DCTSIZE;
+			if (TIFFjpeg_write_raw_data(sp, sp->ds_buffer, n) != n)
+				return (0);
+			sp->scancount = 0;
+		}
+		tif->tif_row += sp->v_sampling;
+		buf += sp->bytesperline;
+		nrows -= sp->v_sampling;
+	}
+	return (1);
+}
+
+/*
+ * Finish up at the end of a strip or tile.
+ */
+static int
+JPEGPostEncode(TIFF* tif)
+{
+	JPEGState *sp = JState(tif);
+
+	if (sp->scancount > 0) {
+		/*
+		 * Need to emit a partial bufferload of downsampled data.
+		 * Pad the data vertically.
+		 */
+		int ci, ypos, n;
+		jpeg_component_info* compptr;
+
+		for (ci = 0, compptr = sp->cinfo.c.comp_info;
+		     ci < sp->cinfo.c.num_components;
+		     ci++, compptr++) {
+			int vsamp = compptr->v_samp_factor;
+			tsize_t row_width = compptr->width_in_blocks * DCTSIZE
+				* sizeof(JSAMPLE);
+			for (ypos = sp->scancount * vsamp;
+			     ypos < DCTSIZE * vsamp; ypos++) {
+				_TIFFmemcpy((tdata_t)sp->ds_buffer[ci][ypos],
+					    (tdata_t)sp->ds_buffer[ci][ypos-1],
+					    row_width);
+
+			}
+		}
+		n = sp->cinfo.c.max_v_samp_factor * DCTSIZE;
+		if (TIFFjpeg_write_raw_data(sp, sp->ds_buffer, n) != n)
+			return (0);
+	}
+
+	return (TIFFjpeg_finish_compress(JState(tif)));
+}
+
+static void
+JPEGCleanup(TIFF* tif)
+{
+	JPEGState *sp = JState(tif);
+	
+	assert(sp != 0);
+
+	tif->tif_tagmethods.vgetfield = sp->vgetparent;
+	tif->tif_tagmethods.vsetfield = sp->vsetparent;
+	tif->tif_tagmethods.printdir = sp->printdir;
+
+	if( sp->cinfo_initialized )
+	    TIFFjpeg_destroy(sp);	/* release libjpeg resources */
+	if (sp->jpegtables)		/* tag value */
+		_TIFFfree(sp->jpegtables);
+	_TIFFfree(tif->tif_data);	/* release local state */
+	tif->tif_data = NULL;
+
+	_TIFFSetDefaultCompressionState(tif);
+}
+
+static void 
+JPEGResetUpsampled( TIFF* tif )
+{
+	JPEGState* sp = JState(tif);
+	TIFFDirectory* td = &tif->tif_dir;
+
+	/*
+	 * Mark whether returned data is up-sampled or not so TIFFStripSize
+	 * and TIFFTileSize return values that reflect the true amount of
+	 * data.
+	 */
+	tif->tif_flags &= ~TIFF_UPSAMPLED;
+	if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
+		if (td->td_photometric == PHOTOMETRIC_YCBCR &&
+		    sp->jpegcolormode == JPEGCOLORMODE_RGB) {
+			tif->tif_flags |= TIFF_UPSAMPLED;
+		} else {
+#ifdef notdef
+			if (td->td_ycbcrsubsampling[0] != 1 ||
+			    td->td_ycbcrsubsampling[1] != 1)
+				; /* XXX what about up-sampling? */
+#endif
+		}
+	}
+
+	/*
+	 * Must recalculate cached tile size in case sampling state changed.
+	 * Should we really be doing this now if image size isn't set? 
+	 */
+	tif->tif_tilesize = isTiled(tif) ? TIFFTileSize(tif) : (tsize_t) -1;
+}
+
+static int
+JPEGVSetField(TIFF* tif, ttag_t tag, va_list ap)
+{
+	JPEGState* sp = JState(tif);
+	const TIFFFieldInfo* fip;
+	uint32 v32;
+
+	assert(sp != NULL);
+
+	switch (tag) {
+	case TIFFTAG_JPEGTABLES:
+		v32 = va_arg(ap, uint32);
+		if (v32 == 0) {
+			/* XXX */
+			return (0);
+		}
+		_TIFFsetByteArray(&sp->jpegtables, va_arg(ap, void*),
+		    (long) v32);
+		sp->jpegtables_length = v32;
+		TIFFSetFieldBit(tif, FIELD_JPEGTABLES);
+		break;
+	case TIFFTAG_JPEGQUALITY:
+		sp->jpegquality = va_arg(ap, int);
+		return (1);			/* pseudo tag */
+	case TIFFTAG_JPEGCOLORMODE:
+		sp->jpegcolormode = va_arg(ap, int);
+                JPEGResetUpsampled( tif );
+		return (1);			/* pseudo tag */
+	case TIFFTAG_PHOTOMETRIC:
+        {
+                int ret_value = (*sp->vsetparent)(tif, tag, ap);
+                JPEGResetUpsampled( tif );
+                return ret_value;
+        }
+	case TIFFTAG_JPEGTABLESMODE:
+		sp->jpegtablesmode = va_arg(ap, int);
+		return (1);			/* pseudo tag */
+	case TIFFTAG_YCBCRSUBSAMPLING:
+                /* mark the fact that we have a real ycbcrsubsampling! */
+		sp->ycbcrsampling_fetched = 1;
+                /* should we be recomputing upsampling info here? */
+		return (*sp->vsetparent)(tif, tag, ap);
+	case TIFFTAG_FAXRECVPARAMS:
+		sp->recvparams = va_arg(ap, uint32);
+		break;
+	case TIFFTAG_FAXSUBADDRESS:
+		_TIFFsetString(&sp->subaddress, va_arg(ap, char*));
+		break;
+	case TIFFTAG_FAXRECVTIME:
+		sp->recvtime = va_arg(ap, uint32);
+		break;
+	case TIFFTAG_FAXDCS:
+		_TIFFsetString(&sp->faxdcs, va_arg(ap, char*));
+		break;
+	default:
+		return (*sp->vsetparent)(tif, tag, ap);
+	}
+
+	if ((fip = _TIFFFieldWithTag(tif, tag))) {
+		TIFFSetFieldBit(tif, fip->field_bit);
+	} else {
+		return (0);
+	}
+
+	tif->tif_flags |= TIFF_DIRTYDIRECT;
+	return (1);
+}
+
+/*
+ * Some JPEG-in-TIFF produces do not emit the YCBCRSUBSAMPLING values in
+ * the TIFF tags, but still use non-default (2,2) values within the jpeg
+ * data stream itself.  In order for TIFF applications to work properly
+ * - for instance to get the strip buffer size right - it is imperative
+ * that the subsampling be available before we start reading the image
+ * data normally.  This function will attempt to load the first strip in
+ * order to get the sampling values from the jpeg data stream.  Various
+ * hacks are various places are done to ensure this function gets called
+ * before the td_ycbcrsubsampling values are used from the directory structure,
+ * including calling TIFFGetField() for the YCBCRSUBSAMPLING field from 
+ * TIFFStripSize(), and the printing code in tif_print.c. 
+ *
+ * Note that JPEGPreDeocode() will produce a fairly loud warning when the
+ * discovered sampling does not match the default sampling (2,2) or whatever
+ * was actually in the tiff tags. 
+ *
+ * Problems:
+ *  o This code will cause one whole strip/tile of compressed data to be
+ *    loaded just to get the tags right, even if the imagery is never read.
+ *    It would be more efficient to just load a bit of the header, and
+ *    initialize things from that. 
+ *
+ * See the bug in bugzilla for details:
+ *
+ * http://bugzilla.remotesensing.org/show_bug.cgi?id=168
+ *
+ * Frank Warmerdam, July 2002
+ */
+
+static void 
+JPEGFixupTestSubsampling( TIFF * tif )
+{
+#ifdef CHECK_JPEG_YCBCR_SUBSAMPLING
+    JPEGState *sp = JState(tif);
+    TIFFDirectory *td = &tif->tif_dir;
+
+    JPEGInitializeLibJPEG( tif, 0, 0 );
+
+    /*
+     * Some JPEG-in-TIFF files don't provide the ycbcrsampling tags, 
+     * and use a sampling schema other than the default 2,2.  To handle
+     * this we actually have to scan the header of a strip or tile of
+     * jpeg data to get the sampling.  
+     */
+    if( !sp->cinfo.comm.is_decompressor 
+        || sp->ycbcrsampling_fetched  
+        || td->td_photometric != PHOTOMETRIC_YCBCR )
+        return;
+
+    sp->ycbcrsampling_fetched = 1;
+    if( TIFFIsTiled( tif ) )
+    {
+        if( !TIFFFillTile( tif, 0 ) )
+			return;
+    }
+    else
+	{
+        if( !TIFFFillStrip( tif, 0 ) )
+            return;
+    }
+
+    TIFFSetField( tif, TIFFTAG_YCBCRSUBSAMPLING, 
+                  (uint16) sp->h_sampling, (uint16) sp->v_sampling );
+#endif /* CHECK_JPEG_YCBCR_SUBSAMPLING */
+}
+
+static int
+JPEGVGetField(TIFF* tif, ttag_t tag, va_list ap)
+{
+	JPEGState* sp = JState(tif);
+
+	assert(sp != NULL);
+
+	switch (tag) {
+		case TIFFTAG_JPEGTABLES:
+			*va_arg(ap, uint32*) = sp->jpegtables_length;
+			*va_arg(ap, void**) = sp->jpegtables;
+			break;
+		case TIFFTAG_JPEGQUALITY:
+			*va_arg(ap, int*) = sp->jpegquality;
+			break;
+		case TIFFTAG_JPEGCOLORMODE:
+			*va_arg(ap, int*) = sp->jpegcolormode;
+			break;
+		case TIFFTAG_JPEGTABLESMODE:
+			*va_arg(ap, int*) = sp->jpegtablesmode;
+			break;
+		case TIFFTAG_YCBCRSUBSAMPLING:
+			JPEGFixupTestSubsampling( tif );
+			return (*sp->vgetparent)(tif, tag, ap);
+		case TIFFTAG_FAXRECVPARAMS:
+			*va_arg(ap, uint32*) = sp->recvparams;
+			break;
+		case TIFFTAG_FAXSUBADDRESS:
+			*va_arg(ap, char**) = sp->subaddress;
+			break;
+		case TIFFTAG_FAXRECVTIME:
+			*va_arg(ap, uint32*) = sp->recvtime;
+			break;
+		case TIFFTAG_FAXDCS:
+			*va_arg(ap, char**) = sp->faxdcs;
+			break;
+		default:
+			return (*sp->vgetparent)(tif, tag, ap);
+	}
+	return (1);
+}
+
+static void
+JPEGPrintDir(TIFF* tif, FILE* fd, long flags)
+{
+	JPEGState* sp = JState(tif);
+
+	assert(sp != NULL);
+
+	(void) flags;
+	if (TIFFFieldSet(tif,FIELD_JPEGTABLES))
+		fprintf(fd, "  JPEG Tables: (%lu bytes)\n",
+			(unsigned long) sp->jpegtables_length);
+        if (TIFFFieldSet(tif,FIELD_RECVPARAMS))
+                fprintf(fd, "  Fax Receive Parameters: %08lx\n",
+                   (unsigned long) sp->recvparams);
+        if (TIFFFieldSet(tif,FIELD_SUBADDRESS))
+                fprintf(fd, "  Fax SubAddress: %s\n", sp->subaddress);
+        if (TIFFFieldSet(tif,FIELD_RECVTIME))
+                fprintf(fd, "  Fax Receive Time: %lu secs\n",
+                    (unsigned long) sp->recvtime);
+        if (TIFFFieldSet(tif,FIELD_FAXDCS))
+                fprintf(fd, "  Fax DCS: %s\n", sp->faxdcs);
+}
+
+static uint32
+JPEGDefaultStripSize(TIFF* tif, uint32 s)
+{
+	JPEGState* sp = JState(tif);
+	TIFFDirectory *td = &tif->tif_dir;
+
+	s = (*sp->defsparent)(tif, s);
+	if (s < td->td_imagelength)
+		s = TIFFroundup(s, td->td_ycbcrsubsampling[1] * DCTSIZE);
+	return (s);
+}
+
+static void
+JPEGDefaultTileSize(TIFF* tif, uint32* tw, uint32* th)
+{
+	JPEGState* sp = JState(tif);
+	TIFFDirectory *td = &tif->tif_dir;
+
+	(*sp->deftparent)(tif, tw, th);
+	*tw = TIFFroundup(*tw, td->td_ycbcrsubsampling[0] * DCTSIZE);
+	*th = TIFFroundup(*th, td->td_ycbcrsubsampling[1] * DCTSIZE);
+}
+
+/*
+ * The JPEG library initialized used to be done in TIFFInitJPEG(), but
+ * now that we allow a TIFF file to be opened in update mode it is necessary
+ * to have some way of deciding whether compression or decompression is
+ * desired other than looking at tif->tif_mode.  We accomplish this by 
+ * examining {TILE/STRIP}BYTECOUNTS to see if there is a non-zero entry.
+ * If so, we assume decompression is desired. 
+ *
+ * This is tricky, because TIFFInitJPEG() is called while the directory is
+ * being read, and generally speaking the BYTECOUNTS tag won't have been read
+ * at that point.  So we try to defer jpeg library initialization till we
+ * do have that tag ... basically any access that might require the compressor
+ * or decompressor that occurs after the reading of the directory. 
+ *
+ * In an ideal world compressors or decompressors would be setup
+ * at the point where a single tile or strip was accessed (for read or write)
+ * so that stuff like update of missing tiles, or replacement of tiles could
+ * be done. However, we aren't trying to crack that nut just yet ...
+ *
+ * NFW, Feb 3rd, 2003.
+ */
+
+static int JPEGInitializeLibJPEG( TIFF * tif, int force_encode, int force_decode )
+{
+    JPEGState* sp = JState(tif);
+    uint32 *byte_counts = NULL;
+    int     data_is_empty = TRUE;
+    int     decompress;
+
+
+    if(sp->cinfo_initialized)
+    {
+        if( force_encode && sp->cinfo.comm.is_decompressor )
+            TIFFjpeg_destroy( sp );
+        else if( force_decode && !sp->cinfo.comm.is_decompressor )
+            TIFFjpeg_destroy( sp );
+        else
+            return 1;
+
+        sp->cinfo_initialized = 0;
+    }
+
+    /*
+     * Do we have tile data already?  Make sure we initialize the
+     * the state in decompressor mode if we have tile data, even if we
+     * are not in read-only file access mode. 
+     */
+    if( TIFFIsTiled( tif ) 
+        && TIFFGetField( tif, TIFFTAG_TILEBYTECOUNTS, &byte_counts ) 
+        && byte_counts != NULL )
+    {
+        data_is_empty = byte_counts[0] == 0;
+    }
+    if( !TIFFIsTiled( tif ) 
+        && TIFFGetField( tif, TIFFTAG_STRIPBYTECOUNTS, &byte_counts) 
+        && byte_counts != NULL )
+    {
+        data_is_empty = byte_counts[0] == 0;
+    }
+
+    if( force_decode )
+        decompress = 1;
+    else if( force_encode )
+        decompress = 0;
+    else if( tif->tif_mode == O_RDONLY )
+        decompress = 1;
+    else if( data_is_empty )
+        decompress = 0;
+    else
+        decompress = 1;
+
+    /*
+     * Initialize libjpeg.
+     */
+    if ( decompress ) {
+        if (!TIFFjpeg_create_decompress(sp))
+            return (0);
+
+    } else {
+        if (!TIFFjpeg_create_compress(sp))
+            return (0);
+    }
+
+    sp->cinfo_initialized = TRUE;
+
+    return 1;
+}
+
+int
+TIFFInitJPEG(TIFF* tif, int scheme)
+{
+	JPEGState* sp;
+
+	assert(scheme == COMPRESSION_JPEG);
+
+	/*
+	 * Merge codec-specific tag information.
+	 */
+	if (!_TIFFMergeFieldInfo(tif, jpegFieldInfo, N(jpegFieldInfo))) {
+		TIFFErrorExt(tif->tif_clientdata,
+			     "TIFFInitJPEG",
+			     "Merging JPEG codec-specific tags failed");
+		return 0;
+	}
+
+	/*
+	 * Allocate state block so tag methods have storage to record values.
+	 */
+	tif->tif_data = (tidata_t) _TIFFmalloc(sizeof (JPEGState));
+
+	if (tif->tif_data == NULL) {
+		TIFFErrorExt(tif->tif_clientdata,
+			     "TIFFInitJPEG", "No space for JPEG state block");
+		return 0;
+	}
+        _TIFFmemset(tif->tif_data, 0, sizeof(JPEGState));
+
+	sp = JState(tif);
+	sp->tif = tif;				/* back link */
+
+	/*
+	 * Override parent get/set field methods.
+	 */
+	sp->vgetparent = tif->tif_tagmethods.vgetfield;
+	tif->tif_tagmethods.vgetfield = JPEGVGetField; /* hook for codec tags */
+	sp->vsetparent = tif->tif_tagmethods.vsetfield;
+	tif->tif_tagmethods.vsetfield = JPEGVSetField; /* hook for codec tags */
+	sp->printdir = tif->tif_tagmethods.printdir;
+	tif->tif_tagmethods.printdir = JPEGPrintDir;   /* hook for codec tags */
+
+	/* Default values for codec-specific fields */
+	sp->jpegtables = NULL;
+	sp->jpegtables_length = 0;
+	sp->jpegquality = 75;			/* Default IJG quality */
+	sp->jpegcolormode = JPEGCOLORMODE_RAW;
+	sp->jpegtablesmode = JPEGTABLESMODE_QUANT | JPEGTABLESMODE_HUFF;
+
+        sp->recvparams = 0;
+        sp->subaddress = NULL;
+        sp->faxdcs = NULL;
+
+        sp->ycbcrsampling_fetched = 0;
+
+	/*
+	 * Install codec methods.
+	 */
+	tif->tif_setupdecode = JPEGSetupDecode;
+	tif->tif_predecode = JPEGPreDecode;
+	tif->tif_decoderow = JPEGDecode;
+	tif->tif_decodestrip = JPEGDecode;
+	tif->tif_decodetile = JPEGDecode;
+	tif->tif_setupencode = JPEGSetupEncode;
+	tif->tif_preencode = JPEGPreEncode;
+	tif->tif_postencode = JPEGPostEncode;
+	tif->tif_encoderow = JPEGEncode;
+	tif->tif_encodestrip = JPEGEncode;
+	tif->tif_encodetile = JPEGEncode;
+	tif->tif_cleanup = JPEGCleanup;
+	sp->defsparent = tif->tif_defstripsize;
+	tif->tif_defstripsize = JPEGDefaultStripSize;
+	sp->deftparent = tif->tif_deftilesize;
+	tif->tif_deftilesize = JPEGDefaultTileSize;
+	tif->tif_flags |= TIFF_NOBITREV;	/* no bit reversal, please */
+
+        sp->cinfo_initialized = FALSE;
+
+	/*
+        ** Create a JPEGTables field if no directory has yet been created. 
+        ** We do this just to ensure that sufficient space is reserved for
+        ** the JPEGTables field.  It will be properly created the right
+        ** size later. 
+        */
+        if( tif->tif_diroff == 0 )
+        {
+#define SIZE_OF_JPEGTABLES 2000
+            TIFFSetFieldBit(tif, FIELD_JPEGTABLES);
+            sp->jpegtables_length = SIZE_OF_JPEGTABLES;
+            sp->jpegtables = (void *) _TIFFmalloc(sp->jpegtables_length);
+	    _TIFFmemset(sp->jpegtables, 0, SIZE_OF_JPEGTABLES);
+#undef SIZE_OF_JPEGTABLES
+        }
+
+        /*
+         * Mark the TIFFTAG_YCBCRSAMPLES as present even if it is not
+         * see: JPEGFixupTestSubsampling().
+         */
+        TIFFSetFieldBit( tif, FIELD_YCBCRSUBSAMPLING );
+
+	return 1;
+}
+#endif /* JPEG_SUPPORT */
+
+/* vim: set ts=8 sts=8 sw=8 noet: */
+