XFA: Upgrade to libtiff 4.0.6.

R=jun_fang@foxitsoftware.com, tsepez@chromium.org

Review URL: https://codereview.chromium.org/1563103002 .

1 files changed, 2429 insertions, 0 deletions

diff --git a/third_party/libtiff/tif_jpeg.c b/third_party/libtiff/tif_jpeg.c
new file mode 100644
index 0000000000..6659909299
--- /dev/null
+++ b/third_party/libtiff/tif_jpeg.c
@@ -0,0 +1,2429 @@
+/* $Id: tif_jpeg.c,v 1.119 2015-08-15 20:13:07 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* tif, uint32 strip);
+int TIFFFillTile(TIFF* tif, uint32 tile);
+int TIFFReInitJPEG_12( TIFF *tif, int scheme, int is_encode );
+
+/* 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
+
+#if defined(USE_SYSTEM_LIBJPEG)
+#include <jerror.h>
+#include <jpeglib.h>
+#elif defined(USE_LIBJPEG_TURBO)
+#include "third_party/libjpeg_turbo/jerror.h"
+#include "third_party/libjpeg_turbo/jpeglib.h"
+#else
+#include "third_party/libjpeg/jerror.h"
+#include "third_party/libjpeg/jpeglib.h"
+#endif
+
+/* 
+ * Do we want to do special processing suitable for when JSAMPLE is a
+ * 16bit value?  
+ */
+
+#if defined(JPEG_LIB_MK1)
+#  define JPEG_LIB_MK1_OR_12BIT 1
+#elif BITS_IN_JSAMPLE == 12
+#  define JPEG_LIB_MK1_OR_12BIT 1
+#endif
+
+/*
+ * 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;
+	tmsize_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;
+} JPEGState;
+
+#define	JState(tif)	((JPEGState*)(tif)->tif_data)
+
+static int JPEGDecode(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s);
+static int JPEGDecodeRaw(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s);
+static int JPEGEncode(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s);
+static int JPEGEncodeRaw(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s);
+static int JPEGInitializeLibJPEG(TIFF * tif, int decode );
+static int DecodeRowError(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s);
+
+#define	FIELD_JPEGTABLES	(FIELD_CODEC+0)
+
+static const TIFFField jpegFields[] = {
+    { TIFFTAG_JPEGTABLES, -3, -3, TIFF_UNDEFINED, 0, TIFF_SETGET_C32_UINT8, TIFF_SETGET_C32_UINT8, FIELD_JPEGTABLES, FALSE, TRUE, "JPEGTables", NULL },
+    { TIFFTAG_JPEGQUALITY, 0, 0, TIFF_ANY, 0, TIFF_SETGET_INT, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, TRUE, FALSE, "", NULL },
+    { TIFFTAG_JPEGCOLORMODE, 0, 0, TIFF_ANY, 0, TIFF_SETGET_INT, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, FALSE, FALSE, "", NULL },
+    { TIFFTAG_JPEGTABLESMODE, 0, 0, TIFF_ANY, 0, TIFF_SETGET_INT, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, FALSE, FALSE, "", NULL }
+};
+
+/*
+ * 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;
+
+	/* set client_data to avoid UMR warning from tools like Purify */
+	sp->cinfo.c.client_data = NULL;
+
+	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;
+
+	/* set client_data to avoid UMR warning from tools like Purify */
+	sp->cinfo.d.client_data = NULL;
+
+	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;
+
+#ifdef IPPJ_HUFF
+       /*
+        * The Intel IPP performance library does not necessarily fill up
+        * the whole output buffer on each pass, so only dump out the parts
+        * that have been filled.
+        *   http://trac.osgeo.org/gdal/wiki/JpegIPP
+        */
+       if ( sp->dest.free_in_buffer >= 0 ) {
+               tif->tif_rawcc = tif->tif_rawdatasize - sp->dest.free_in_buffer;
+       }
+#endif
+
+	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 = (uint8*) sp->dest.next_output_byte;
+	tif->tif_rawcc =
+	    tif->tif_rawdatasize - (tmsize_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((void*) sp->jpegtables,
+			      (tmsize_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 -= (uint32) 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((tmsize_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 };
+
+#ifdef IPPJ_HUFF
+        /*
+         * The Intel IPP performance library does not necessarily read the whole
+         * input buffer in one pass, so it is possible to get here with data
+         * yet to read. 
+         * 
+         * We just return without doing anything, until the entire buffer has
+         * been read.  
+         * http://trac.osgeo.org/gdal/wiki/JpegIPP
+         */
+        if( sp->src.bytes_in_buffer > 0 ) {
+            return (TRUE);
+        }
+#endif
+
+	/*
+         * Normally the whole strip/tile is read and so we don't need to do
+         * a fill.  In the case of CHUNKY_STRIP_READ_SUPPORT we might not have
+         * all the data, but the rawdata is refreshed between scanlines and
+         * we push this into the io machinery in JPEGDecode(). 	 
+         * http://trac.osgeo.org/gdal/ticket/3894
+	 */
+        
+	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 ((size_t)num_bytes > 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 */
+	(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.
+ */
+
+#ifdef CHECK_JPEG_YCBCR_SUBSAMPLING
+
+#define JPEG_MARKER_SOF0 0xC0
+#define JPEG_MARKER_SOF1 0xC1
+#define JPEG_MARKER_SOF2 0xC2
+#define JPEG_MARKER_SOF9 0xC9
+#define JPEG_MARKER_SOF10 0xCA
+#define JPEG_MARKER_DHT 0xC4
+#define JPEG_MARKER_SOI 0xD8
+#define JPEG_MARKER_SOS 0xDA
+#define JPEG_MARKER_DQT 0xDB
+#define JPEG_MARKER_DRI 0xDD
+#define JPEG_MARKER_APP0 0xE0
+#define JPEG_MARKER_COM 0xFE
+struct JPEGFixupTagsSubsamplingData
+{
+	TIFF* tif;
+	void* buffer;
+	uint32 buffersize;
+	uint8* buffercurrentbyte;
+	uint32 bufferbytesleft;
+	uint64 fileoffset;
+	uint64 filebytesleft;
+	uint8 filepositioned;
+};
+static void JPEGFixupTagsSubsampling(TIFF* tif);
+static int JPEGFixupTagsSubsamplingSec(struct JPEGFixupTagsSubsamplingData* data);
+static int JPEGFixupTagsSubsamplingReadByte(struct JPEGFixupTagsSubsamplingData* data, uint8* result);
+static int JPEGFixupTagsSubsamplingReadWord(struct JPEGFixupTagsSubsamplingData* data, uint16* result);
+static void JPEGFixupTagsSubsamplingSkip(struct JPEGFixupTagsSubsamplingData* data, uint16 skiplength);
+
+#endif
+
+static int
+JPEGFixupTags(TIFF* tif)
+{
+#ifdef CHECK_JPEG_YCBCR_SUBSAMPLING
+	if ((tif->tif_dir.td_photometric==PHOTOMETRIC_YCBCR)&&
+	    (tif->tif_dir.td_planarconfig==PLANARCONFIG_CONTIG)&&
+	    (tif->tif_dir.td_samplesperpixel==3))
+		JPEGFixupTagsSubsampling(tif);
+#endif
+        
+	return(1);
+}
+
+#ifdef CHECK_JPEG_YCBCR_SUBSAMPLING
+
+static void
+JPEGFixupTagsSubsampling(TIFF* tif)
+{
+	/*
+	 * 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 analyze the first strip in
+	 * order to get the sampling values from the jpeg data stream.
+	 *
+	 * 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.
+	 *
+	 * See the bug in bugzilla for details:
+	 *
+	 * http://bugzilla.remotesensing.org/show_bug.cgi?id=168
+	 *
+	 * Frank Warmerdam, July 2002
+	 * Joris Van Damme, May 2007
+	 */
+	static const char module[] = "JPEGFixupTagsSubsampling";
+	struct JPEGFixupTagsSubsamplingData m;
+
+        _TIFFFillStriles( tif );
+        
+        if( tif->tif_dir.td_stripbytecount == NULL
+            || tif->tif_dir.td_stripoffset == NULL
+            || tif->tif_dir.td_stripbytecount[0] == 0 )
+        {
+            /* Do not even try to check if the first strip/tile does not
+               yet exist, as occurs when GDAL has created a new NULL file
+               for instance. */
+            return;
+        }
+
+	m.tif=tif;
+	m.buffersize=2048;
+	m.buffer=_TIFFmalloc(m.buffersize);
+	if (m.buffer==NULL)
+	{
+		TIFFWarningExt(tif->tif_clientdata,module,
+		    "Unable to allocate memory for auto-correcting of subsampling values; auto-correcting skipped");
+		return;
+	}
+	m.buffercurrentbyte=NULL;
+	m.bufferbytesleft=0;
+	m.fileoffset=tif->tif_dir.td_stripoffset[0];
+	m.filepositioned=0;
+	m.filebytesleft=tif->tif_dir.td_stripbytecount[0];
+	if (!JPEGFixupTagsSubsamplingSec(&m))
+		TIFFWarningExt(tif->tif_clientdata,module,
+		    "Unable to auto-correct subsampling values, likely corrupt JPEG compressed data in first strip/tile; auto-correcting skipped");
+	_TIFFfree(m.buffer);
+}
+
+static int
+JPEGFixupTagsSubsamplingSec(struct JPEGFixupTagsSubsamplingData* data)
+{
+	static const char module[] = "JPEGFixupTagsSubsamplingSec";
+	uint8 m;
+	while (1)
+	{
+		while (1)
+		{
+			if (!JPEGFixupTagsSubsamplingReadByte(data,&m))
+				return(0);
+			if (m==255)
+				break;
+		}
+		while (1)
+		{
+			if (!JPEGFixupTagsSubsamplingReadByte(data,&m))
+				return(0);
+			if (m!=255)
+				break;
+		}
+		switch (m)
+		{
+			case JPEG_MARKER_SOI:
+				/* this type of marker has no data and should be skipped */
+				break;
+			case JPEG_MARKER_COM:
+			case JPEG_MARKER_APP0:
+			case JPEG_MARKER_APP0+1:
+			case JPEG_MARKER_APP0+2:
+			case JPEG_MARKER_APP0+3:
+			case JPEG_MARKER_APP0+4:
+			case JPEG_MARKER_APP0+5:
+			case JPEG_MARKER_APP0+6:
+			case JPEG_MARKER_APP0+7:
+			case JPEG_MARKER_APP0+8:
+			case JPEG_MARKER_APP0+9:
+			case JPEG_MARKER_APP0+10:
+			case JPEG_MARKER_APP0+11:
+			case JPEG_MARKER_APP0+12:
+			case JPEG_MARKER_APP0+13:
+			case JPEG_MARKER_APP0+14:
+			case JPEG_MARKER_APP0+15:
+			case JPEG_MARKER_DQT:
+			case JPEG_MARKER_SOS:
+			case JPEG_MARKER_DHT:
+			case JPEG_MARKER_DRI:
+				/* this type of marker has data, but it has no use to us and should be skipped */
+				{
+					uint16 n;
+					if (!JPEGFixupTagsSubsamplingReadWord(data,&n))
+						return(0);
+					if (n<2)
+						return(0);
+					n-=2;
+					if (n>0)
+						JPEGFixupTagsSubsamplingSkip(data,n);
+				}
+				break;
+			case JPEG_MARKER_SOF0: /* Baseline sequential Huffman */
+			case JPEG_MARKER_SOF1: /* Extended sequential Huffman */
+			case JPEG_MARKER_SOF2: /* Progressive Huffman: normally not allowed by TechNote, but that doesn't hurt supporting it */
+			case JPEG_MARKER_SOF9: /* Extended sequential arithmetic */
+			case JPEG_MARKER_SOF10: /* Progressive arithmetic: normally not allowed by TechNote, but that doesn't hurt supporting it */
+				/* this marker contains the subsampling factors we're scanning for */
+				{
+					uint16 n;
+					uint16 o;
+					uint8 p;
+					uint8 ph,pv;
+					if (!JPEGFixupTagsSubsamplingReadWord(data,&n))
+						return(0);
+					if (n!=8+data->tif->tif_dir.td_samplesperpixel*3)
+						return(0);
+					JPEGFixupTagsSubsamplingSkip(data,7);
+					if (!JPEGFixupTagsSubsamplingReadByte(data,&p))
+						return(0);
+					ph=(p>>4);
+					pv=(p&15);
+					JPEGFixupTagsSubsamplingSkip(data,1);
+					for (o=1; o<data->tif->tif_dir.td_samplesperpixel; o++)
+					{
+						JPEGFixupTagsSubsamplingSkip(data,1);
+						if (!JPEGFixupTagsSubsamplingReadByte(data,&p))
+							return(0);
+						if (p!=0x11)
+						{
+							TIFFWarningExt(data->tif->tif_clientdata,module,
+							    "Subsampling values inside JPEG compressed data have no TIFF equivalent, auto-correction of TIFF subsampling values failed");
+							return(1);
+						}
+						JPEGFixupTagsSubsamplingSkip(data,1);
+					}
+					if (((ph!=1)&&(ph!=2)&&(ph!=4))||((pv!=1)&&(pv!=2)&&(pv!=4)))
+					{
+						TIFFWarningExt(data->tif->tif_clientdata,module,
+						    "Subsampling values inside JPEG compressed data have no TIFF equivalent, auto-correction of TIFF subsampling values failed");
+						return(1);
+					}
+					if ((ph!=data->tif->tif_dir.td_ycbcrsubsampling[0])||(pv!=data->tif->tif_dir.td_ycbcrsubsampling[1]))
+					{
+						TIFFWarningExt(data->tif->tif_clientdata,module,
+						    "Auto-corrected former TIFF subsampling values [%d,%d] to match subsampling values inside JPEG compressed data [%d,%d]",
+						    (int)data->tif->tif_dir.td_ycbcrsubsampling[0],
+						    (int)data->tif->tif_dir.td_ycbcrsubsampling[1],
+						    (int)ph,(int)pv);
+						data->tif->tif_dir.td_ycbcrsubsampling[0]=ph;
+						data->tif->tif_dir.td_ycbcrsubsampling[1]=pv;
+					}
+				}
+				return(1);
+			default:
+				return(0);
+		}
+	}
+}
+
+static int
+JPEGFixupTagsSubsamplingReadByte(struct JPEGFixupTagsSubsamplingData* data, uint8* result)
+{
+	if (data->bufferbytesleft==0)
+	{
+		uint32 m;
+		if (data->filebytesleft==0)
+			return(0);
+		if (!data->filepositioned)
+		{
+			TIFFSeekFile(data->tif,data->fileoffset,SEEK_SET);
+			data->filepositioned=1;
+		}
+		m=data->buffersize;
+		if ((uint64)m>data->filebytesleft)
+			m=(uint32)data->filebytesleft;
+		assert(m<0x80000000UL);
+		if (TIFFReadFile(data->tif,data->buffer,(tmsize_t)m)!=(tmsize_t)m)
+			return(0);
+		data->buffercurrentbyte=data->buffer;
+		data->bufferbytesleft=m;
+		data->fileoffset+=m;
+		data->filebytesleft-=m;
+	}
+	*result=*data->buffercurrentbyte;
+	data->buffercurrentbyte++;
+	data->bufferbytesleft--;
+	return(1);
+}
+
+static int
+JPEGFixupTagsSubsamplingReadWord(struct JPEGFixupTagsSubsamplingData* data, uint16* result)
+{
+	uint8 ma;
+	uint8 mb;
+	if (!JPEGFixupTagsSubsamplingReadByte(data,&ma))
+		return(0);
+	if (!JPEGFixupTagsSubsamplingReadByte(data,&mb))
+		return(0);
+	*result=(ma<<8)|mb;
+	return(1);
+}
+
+static void
+JPEGFixupTagsSubsamplingSkip(struct JPEGFixupTagsSubsamplingData* data, uint16 skiplength)
+{
+	if ((uint32)skiplength<=data->bufferbytesleft)
+	{
+		data->buffercurrentbyte+=skiplength;
+		data->bufferbytesleft-=skiplength;
+	}
+	else
+	{
+		uint16 m;
+		m=skiplength-data->bufferbytesleft;
+		if (m<=data->filebytesleft)
+		{
+			data->bufferbytesleft=0;
+			data->fileoffset+=m;
+			data->filebytesleft-=m;
+			data->filepositioned=0;
+		}
+		else
+		{
+			data->bufferbytesleft=0;
+			data->filebytesleft=0;
+		}
+	}
+}
+
+#endif
+
+
+static int
+JPEGSetupDecode(TIFF* tif)
+{
+	JPEGState* sp = JState(tif);
+	TIFFDirectory *td = &tif->tif_dir;
+
+#if defined(JPEG_DUAL_MODE_8_12) && !defined(TIFFInitJPEG)
+        if( tif->tif_dir.td_bitspersample == 12 )
+            return TIFFReInitJPEG_12( tif, COMPRESSION_JPEG, 0 );
+#endif
+
+	JPEGInitializeLibJPEG( tif, TRUE );
+
+	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.
+ */
+/*ARGSUSED*/ static int
+JPEGPreDecode(TIFF* tif, uint16 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);
+  
+	if (sp->cinfo.comm.is_decompressor == 0)
+	{
+		tif->tif_setupdecode( tif );
+	}
+  
+	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);
+
+        tif->tif_rawcp = (uint8*) sp->src.next_input_byte;
+        tif->tif_rawcc = sp->src.bytes_in_buffer;
+
+	/*
+	 * 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 = TIFFScanlineSize(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_32(segment_width, sp->h_sampling);
+		segment_height = TIFFhowmany_32(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) {
+			TIFFErrorExt(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);
+			return (0);
+		}
+		/* 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;
+#if JPEG_LIB_VERSION >= 70
+		sp->cinfo.d.do_fancy_upsampling = FALSE;
+#endif /* JPEG_LIB_VERSION >= 70 */
+		tif->tif_decoderow = DecodeRowError;
+		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.
+ */
+#if !JPEG_LIB_MK1_OR_12BIT
+static int
+JPEGDecode(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s)
+{
+	JPEGState *sp = JState(tif);
+	tmsize_t nrows;
+	(void) s;
+
+        /*
+        ** Update available information, buffer may have been refilled
+        ** between decode requests
+        */
+	sp->src.next_input_byte = (const JOCTET*) tif->tif_rawcp;
+	sp->src.bytes_in_buffer = (size_t) tif->tif_rawcc;
+
+        if( sp->bytesperline == 0 )
+                return 0;
+        
+	nrows = cc / sp->bytesperline;
+	if (cc % sp->bytesperline)
+		TIFFWarningExt(tif->tif_clientdata, tif->tif_name,
+                               "fractional scanline not read");
+
+	if( nrows > (tmsize_t) sp->cinfo.d.image_height )
+		nrows = sp->cinfo.d.image_height;
+
+	/* data is expected to be read in multiples of a scanline */
+	if (nrows)
+        {
+                do
+                {
+                        /*
+                         * In the libjpeg6b-9a 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);
+        }
+
+        /* Update information on consumed data */
+        tif->tif_rawcp = (uint8*) sp->src.next_input_byte;
+        tif->tif_rawcc = sp->src.bytes_in_buffer;
+                
+	/* 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);
+}
+#endif /* !JPEG_LIB_MK1_OR_12BIT */
+
+#if JPEG_LIB_MK1_OR_12BIT
+/*ARGSUSED*/ static int
+JPEGDecode(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s)
+{
+	JPEGState *sp = JState(tif);
+	tmsize_t nrows;
+	(void) s;
+
+        /*
+        ** Update available information, buffer may have been refilled
+        ** between decode requests
+        */
+	sp->src.next_input_byte = (const JOCTET*) tif->tif_rawcp;
+	sp->src.bytes_in_buffer = (size_t) tif->tif_rawcc;
+
+        if( sp->bytesperline == 0 )
+                return 0;
+        
+	nrows = cc / sp->bytesperline;
+	if (cc % sp->bytesperline)
+		TIFFWarningExt(tif->tif_clientdata, tif->tif_name,
+                               "fractional scanline not read");
+
+	if( nrows > (tmsize_t) 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( sp->cinfo.d.data_precision == 12 )
+                {
+                        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;
+                                       }
+                               }
+                       }
+
+                       ++tif->tif_row;
+                       buf += sp->bytesperline;
+                       cc -= sp->bytesperline;
+               } while (--nrows > 0);
+
+               if( line_work_buf != NULL )
+                       _TIFFfree( line_work_buf );
+        }
+
+        /* Update information on consumed data */
+        tif->tif_rawcp = (uint8*) sp->src.next_input_byte;
+        tif->tif_rawcc = sp->src.bytes_in_buffer;
+                
+	/* 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);
+}
+#endif /* JPEG_LIB_MK1_OR_12BIT */
+
+/*ARGSUSED*/ static int
+DecodeRowError(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s)
+
+{
+    (void) buf;
+    (void) cc;
+    (void) s;
+
+    TIFFErrorExt(tif->tif_clientdata, "TIFFReadScanline",
+                 "scanline oriented access is not supported for downsampled JPEG compressed images, consider enabling TIFF_JPEGCOLORMODE as JPEGCOLORMODE_RGB." );
+    return 0;
+}
+
+/*
+ * Decode a chunk of pixels.
+ * Returned data is downsampled per sampling factors.
+ */
+/*ARGSUSED*/ static int
+JPEGDecodeRaw(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s)
+{
+	JPEGState *sp = JState(tif);
+	tmsize_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;
+
+#if defined(JPEG_LIB_MK1_OR_12BIT)
+		unsigned short* tmpbuf = _TIFFmalloc(sizeof(unsigned short) *
+						     sp->cinfo.d.output_width *
+						     sp->cinfo.d.num_components);
+		if(tmpbuf==NULL) {
+                        TIFFErrorExt(tif->tif_clientdata, "JPEGDecodeRaw",
+				     "Out of memory");
+			return 0;
+                }
+#endif
+
+		do {
+			jpeg_component_info *compptr;
+			int ci, clumpoffset;
+
+                        if( cc < sp->bytesperline ) {
+				TIFFErrorExt(tif->tif_clientdata, "JPEGDecodeRaw",
+					     "application buffer not large enough for all data.");
+				return 0;
+                        }
+
+			/* 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];
+					JDIMENSION nclump;
+#if defined(JPEG_LIB_MK1_OR_12BIT)
+					JSAMPLE *outptr = (JSAMPLE*)tmpbuf + clumpoffset;
+#else
+					JSAMPLE *outptr = (JSAMPLE*)buf + clumpoffset;
+					if (cc < (tmsize_t) (clumpoffset + samples_per_clump*(clumps_per_line-1) + hsamp)) {
+						TIFFErrorExt(tif->tif_clientdata, "JPEGDecodeRaw",
+							     "application buffer not large enough for all data, possible subsampling issue");
+						return 0;
+					}
+#endif
+
+					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;
+				}
+			}
+
+#if defined(JPEG_LIB_MK1_OR_12BIT)
+			{
+				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 = (JSAMPLE *) (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;
+
+			buf += sp->bytesperline;
+			cc -= sp->bytesperline;
+
+			nrows -= sp->v_sampling;
+		} while (nrows > 0);
+
+#if defined(JPEG_LIB_MK1_OR_12BIT)
+		_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
+suppress_quant_table (JPEGState* sp, int tblno)
+{
+	JQUANT_TBL* qtbl;
+
+	if ((qtbl = sp->cinfo.c.quant_tbl_ptrs[tblno]) != NULL)
+		qtbl->sent_table = TRUE;
+}
+
+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 void
+suppress_huff_table (JPEGState* sp, int tblno)
+{
+	JHUFF_TBL* htbl;
+
+	if ((htbl = sp->cinfo.c.dc_huff_tbl_ptrs[tblno]) != NULL)
+		htbl->sent_table = TRUE;
+	if ((htbl = sp->cinfo.c.ac_huff_tbl_ptrs[tblno]) != NULL)
+		htbl->sent_table = TRUE;
+}
+
+static int
+prepare_JPEGTables(TIFF* tif)
+{
+	JPEGState* sp = JState(tif);
+
+	/* 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";
+
+#if defined(JPEG_DUAL_MODE_8_12) && !defined(TIFFInitJPEG)
+        if( tif->tif_dir.td_bitspersample == 12 )
+            return TIFFReInitJPEG_12( tif, COMPRESSION_JPEG, 1 );
+#endif
+
+        JPEGInitializeLibJPEG( tif, FALSE );
+
+	assert(sp != NULL);
+	assert(!sp->cinfo.comm.is_decompressor);
+
+	sp->photometric = td->td_photometric;
+
+	/*
+	 * Initialize all JPEG parameters to default values.
+	 * Note that jpeg_set_defaults needs legal values for
+	 * in_color_space and input_components.
+	 */
+	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;
+			}
+		} else {
+			if ((td->td_photometric == PHOTOMETRIC_MINISWHITE || td->td_photometric == PHOTOMETRIC_MINISBLACK) && td->td_samplesperpixel == 1)
+				sp->cinfo.c.in_color_space = JCS_GRAYSCALE;
+			else if (td->td_photometric == PHOTOMETRIC_RGB && td->td_samplesperpixel == 3)
+				sp->cinfo.c.in_color_space = JCS_RGB;
+			else if (td->td_photometric == PHOTOMETRIC_SEPARATED && td->td_samplesperpixel == 4)
+				sp->cinfo.c.in_color_space = JCS_CMYK;
+			else
+				sp->cinfo.c.in_color_space = JCS_UNKNOWN;
+		}
+	} else {
+		sp->cinfo.c.input_components = 1;
+		sp->cinfo.c.in_color_space = JCS_UNKNOWN;
+	}
+	if (!TIFFjpeg_set_defaults(sp))
+		return (0);
+	/* Set per-file parameters */
+	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( sp->jpegtables == NULL
+                    || memcmp(sp->jpegtables,"\0\0\0\0\0\0\0\0\0",8) == 0 )
+                {
+                        if (!prepare_JPEGTables(tif))
+                                return (0);
+                        /* Mark the field present */
+                        /* Can't use TIFFSetField since BEENWRITING is already set! */
+                        tif->tif_flags |= TIFF_DIRTYDIRECT;
+                        TIFFSetFieldBit(tif, FIELD_JPEGTABLES);
+                }
+	} 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, uint16 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);
+  
+	if (sp->cinfo.comm.is_decompressor == 1)
+	{
+		tif->tif_setupencode( tif );
+	}
+  
+	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 = TIFFScanlineSize(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_32(segment_width, sp->h_sampling); 
+		segment_height = TIFFhowmany_32(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) {
+				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 {
+			if (!TIFFjpeg_set_colorspace(sp, sp->cinfo.c.in_color_space))
+				return (0);
+			/* jpeg_set_colorspace set all sampling factors to 1 */
+		}
+	} else {
+		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 */
+	/* calling TIFFjpeg_set_quality() causes quantization tables to be flagged */
+	/* as being to be emitted, which we don't want in the JPEGTABLESMODE_QUANT */
+	/* mode, so we must manually suppress them. However TIFFjpeg_set_quality() */
+	/* should really be called when dealing with files with directories with */
+	/* mixed qualities. see http://trac.osgeo.org/gdal/ticket/3539 */
+	if (!TIFFjpeg_set_quality(sp, sp->jpegquality, FALSE))
+		return (0);
+	if (sp->jpegtablesmode & JPEGTABLESMODE_QUANT) {
+		suppress_quant_table(sp, 0);
+		suppress_quant_table(sp, 1);
+	}
+	else {
+		unsuppress_quant_table(sp, 0);
+		unsuppress_quant_table(sp, 1);
+	}
+	if (sp->jpegtablesmode & JPEGTABLESMODE_HUFF)
+	{
+		/* Explicit suppression is only needed if we did not go through the */
+		/* prepare_JPEGTables() code path, which may be the case if updating */
+		/* an existing file */
+		suppress_huff_table(sp, 0);
+		suppress_huff_table(sp, 1);
+		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, uint8* buf, tmsize_t cc, uint16 s)
+{
+	JPEGState *sp = JState(tif);
+	tmsize_t nrows;
+	JSAMPROW bufptr[1];
+        short *line16 = NULL;
+        int    line16_count = 0;
+
+	(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;
+
+        if( sp->cinfo.c.data_precision == 12 )
+        {
+            line16_count = (sp->bytesperline * 2) / 3;
+            line16 = (short *) _TIFFmalloc(sizeof(short) * line16_count);
+            if (!line16)
+            {
+                TIFFErrorExt(tif->tif_clientdata,
+			     "JPEGEncode",
+                             "Failed to allocate memory");
+
+                return 0;
+            }
+        }
+            
+	while (nrows-- > 0) {
+
+            if( sp->cinfo.c.data_precision == 12 )
+            {
+
+                int value_pairs = line16_count / 2;
+                int iPair;
+
+		bufptr[0] = (JSAMPROW) line16;
+
+                for( iPair = 0; iPair < value_pairs; iPair++ )
+                {
+                    unsigned char *in_ptr =
+                        ((unsigned char *) buf) + iPair * 3;
+                    JSAMPLE *out_ptr = (JSAMPLE *) (line16 + iPair * 2);
+
+                    out_ptr[0] = (in_ptr[0] << 4) | ((in_ptr[1] & 0xf0) >> 4);
+                    out_ptr[1] = ((in_ptr[1] & 0x0f) << 8) | in_ptr[2];
+                }
+            }
+            else
+            {
+		bufptr[0] = (JSAMPROW) buf;
+            }
+            if (TIFFjpeg_write_scanlines(sp, bufptr, 1) != 1)
+                return (0);
+            if (nrows > 0)
+                tif->tif_row++;
+            buf += sp->bytesperline;
+	}
+
+        if( sp->cinfo.c.data_precision == 12 )
+        {
+            _TIFFfree( line16 );
+        }
+            
+	return (1);
+}
+
+/*
+ * Encode a chunk of pixels.
+ * Incoming data is expected to be downsampled per sampling factors.
+ */
+static int
+JPEGEncodeRaw(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s)
+{
+	JPEGState *sp = JState(tif);
+	JSAMPLE* inptr;
+	JSAMPLE* outptr;
+	tmsize_t nrows;
+	JDIMENSION clumps_per_line, nclump;
+	int clumpoffset, ci, xpos, ypos;
+	jpeg_component_info* compptr;
+	int samples_per_clump = sp->samplesperclump;
+	tmsize_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 += bytesperclumpline;
+		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;
+			tmsize_t row_width = compptr->width_in_blocks * DCTSIZE
+				* sizeof(JSAMPLE);
+			for (ypos = sp->scancount * vsamp;
+			     ypos < DCTSIZE * vsamp; ypos++) {
+				_TIFFmemcpy((void*)sp->ds_buffer[ci][ypos],
+					    (void*)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? 
+	 */
+        if( tif->tif_tilesize > 0 )
+            tif->tif_tilesize = isTiled(tif) ? TIFFTileSize(tif) : (tmsize_t)(-1);   
+        if( tif->tif_scanlinesize > 0 )
+            tif->tif_scanlinesize = TIFFScanlineSize(tif); 
+}
+
+static int
+JPEGVSetField(TIFF* tif, uint32 tag, va_list ap)
+{
+	JPEGState* sp = JState(tif);
+	const TIFFField* fip;
+	uint32 v32;
+
+	assert(sp != NULL);
+
+	switch (tag) {
+	case TIFFTAG_JPEGTABLES:
+		v32 = (uint32) 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 = (int) va_arg(ap, int);
+		return (1);			/* pseudo tag */
+	case TIFFTAG_JPEGCOLORMODE:
+		sp->jpegcolormode = (int) 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 = (int) 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);
+	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);
+}
+
+static int
+JPEGVGetField(TIFF* tif, uint32 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;
+		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( sp != NULL ) {
+		if (TIFFFieldSet(tif,FIELD_JPEGTABLES))
+			fprintf(fd, "  JPEG Tables: (%lu bytes)\n",
+				(unsigned long) sp->jpegtables_length);
+		if (sp->printdir)
+			(*sp->printdir)(tif, fd, flags);
+	}
+}
+
+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_32(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_32(*tw, td->td_ycbcrsubsampling[0] * DCTSIZE);
+	*th = TIFFroundup_32(*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 decompress )
+{
+    JPEGState* sp = JState(tif);
+
+    if(sp->cinfo_initialized)
+    {
+        if( !decompress && sp->cinfo.comm.is_decompressor )
+            TIFFjpeg_destroy( sp );
+        else if( decompress && !sp->cinfo.comm.is_decompressor )
+            TIFFjpeg_destroy( sp );
+        else
+            return 1;
+
+        sp->cinfo_initialized = 0;
+    }
+
+    /*
+     * 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 (!_TIFFMergeFields(tif, jpegFields, TIFFArrayCount(jpegFields))) {
+		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 = (uint8*) _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->ycbcrsampling_fetched = 0;
+
+	/*
+	 * Install codec methods.
+	 */
+	tif->tif_fixuptags = JPEGFixupTags;
+	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
+/*
+The following line assumes incorrectly that all JPEG-in-TIFF files will have
+a JPEGTABLES tag generated and causes null-filled JPEGTABLES tags to be written
+when the JPEG data is placed with TIFFWriteRawStrip.  The field bit should be 
+set, anyway, later when actual JPEGTABLES header is generated, so removing it 
+here hopefully is harmless.
+            TIFFSetFieldBit(tif, FIELD_JPEGTABLES);
+*/
+            sp->jpegtables_length = SIZE_OF_JPEGTABLES;
+            sp->jpegtables = (void *) _TIFFmalloc(sp->jpegtables_length);
+            if (sp->jpegtables)
+            {
+                _TIFFmemset(sp->jpegtables, 0, SIZE_OF_JPEGTABLES);
+            }
+            else
+            {
+                TIFFErrorExt(tif->tif_clientdata,
+			     "TIFFInitJPEG",
+                             "Failed to allocate memory for JPEG tables");
+                return 0;
+            }
+#undef SIZE_OF_JPEGTABLES
+        }
+
+	return 1;
+}
+#endif /* JPEG_SUPPORT */
+
+/* vim: set ts=8 sts=8 sw=8 noet: */
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 8
+ * fill-column: 78
+ * End:
+ */