Allow in-place updating of the compressed images (don't work properly with

all codecs). For details see GDAL bug
http://bugzilla.remotesensing.org/show_bug.cgi?id=534

libtiff/tif_write.c

@@ -1,4 +1,4 @@
-/* $Header: /cvs/maptools/cvsroot/libtiff/libtiff/tif_write.c,v 1.10 2004-01-20 19:28:05 dron Exp $ */
+/* $Header: /cvs/maptools/cvsroot/libtiff/libtiff/tif_write.c,v 1.11 2004-04-14 06:34:40 dron Exp $ */
 
 /*
  * Copyright (c) 1988-1997 Sam Leffler
@@ -33,8 +33,6 @@
 #include <assert.h>
 #include <stdio.h>
 
-#define REWRITE_HACK
-
 #define	STRIPINCR	20		/* expansion factor on strip array */
 
 #define	WRITECHECKSTRIPS(tif, module)				\
@@ -114,6 +112,19 @@ TIFFWriteScanline(TIFF* tif, tdata_t buf, uint32 row, tsample_t sample)
 				return (-1);
 			tif->tif_flags |= TIFF_CODERSETUP;
 		}
+        
+		tif->tif_rawcc = 0;
+		tif->tif_rawcp = tif->tif_rawdata;
+
+		if( td->td_stripbytecount[strip] > 0 )
+		{
+			/* if we are writing over existing tiles, zero length */
+			td->td_stripbytecount[strip] = 0;
+
+			/* this forces TIFFAppendToStrip() to do a seek */
+			tif->tif_curoff = 0;
+		}
+
 		if (!(*tif->tif_preencode)(tif, sample))
 			return (-1);
 		tif->tif_flags |= TIFF_POSTENCODE;
@@ -166,8 +177,7 @@ TIFFWriteScanline(TIFF* tif, tdata_t buf, uint32 row, tsample_t sample)
 
 /*
  * Encode the supplied data and write it to the
- * specified strip.  There must be space for the
+ * specified strip.
- * data; we don't check if strips overlap!
  *
  * NB: Image length must be setup before writing.
  */
@@ -215,7 +225,6 @@ TIFFWriteEncodedStrip(TIFF* tif, tstrip_t strip, tdata_t data, tsize_t cc)
 		tif->tif_flags |= TIFF_CODERSETUP;
 	}
         
-#ifdef REWRITE_HACK        
 	tif->tif_rawcc = 0;
 	tif->tif_rawcp = tif->tif_rawdata;
 
@@ -227,7 +236,6 @@ TIFFWriteEncodedStrip(TIFF* tif, tstrip_t strip, tdata_t data, tsize_t cc)
             /* this forces TIFFAppendToStrip() to do a seek */
             tif->tif_curoff = 0;
         }
-#endif
         
 	tif->tif_flags &= ~TIFF_POSTENCODE;
 	sample = (tsample_t)(strip / td->td_stripsperimage);
@@ -254,8 +262,6 @@ TIFFWriteEncodedStrip(TIFF* tif, tstrip_t strip, tdata_t data, tsize_t cc)
 
 /*
  * Write the supplied data to the specified strip.
- * There must be space for the data; we don't check
- * if strips overlap!
  *
  * NB: Image length must be setup before writing.
  */
@@ -355,7 +361,6 @@ TIFFWriteEncodedTile(TIFF* tif, ttile_t tile, tdata_t data, tsize_t cc)
 		return ((tsize_t) -1);
 	tif->tif_curtile = tile;
 
-#ifdef REWRITE_HACK        
 	tif->tif_rawcc = 0;
 	tif->tif_rawcp = tif->tif_rawdata;
 
@@ -367,7 +372,6 @@ TIFFWriteEncodedTile(TIFF* tif, ttile_t tile, tdata_t data, tsize_t cc)
             /* this forces TIFFAppendToStrip() to do a seek */
             tif->tif_curoff = 0;
         }
-#endif
         
 	/* 
 	 * Compute tiles per row & per column to compute
@@ -497,23 +501,6 @@ TIFFWriteCheck(TIFF* tif, int tiles, const char* module)
 		return (0);
 	}
         
-        /*
-         * While we allow compressed TIFF files to be opened in update mode,
-         * we don't allow writing any image blocks in an existing compressed
-         * image.  Eventually we could do so, by moving blocks that grow
-         * to the end of the file, but we don't for now. 
-         */
-	if (tif->tif_dir.td_stripoffset != NULL 
-            && tif->tif_dir.td_compression != COMPRESSION_NONE )
-        {
-            TIFFError( module,
-                       "%s:\n"
-                       "In place update to compressed TIFF images not "
-                       "supported.",
-                       tif->tif_name );
-            return (0);
-        }
-
 	/*
 	 * On the first write verify all the required information
 	 * has been setup and initialize any data structures that
@@ -618,9 +605,6 @@ TIFFGrowStrips(TIFF* tif, int delta, const char* module)
 
 /*
  * Append the data to the specified strip.
- *
- * NB: We don't check that there's space in the
- *     file (i.e. that strips do not overlap).
  */
 static int
 TIFFAppendToStrip(TIFF* tif, tstrip_t strip, tidata_t data, tsize_t cc)
@@ -633,6 +617,25 @@ TIFFAppendToStrip(TIFF* tif, tstrip_t strip, tidata_t data, tsize_t cc)
 		 * No current offset, set the current strip.
 		 */
 		if (td->td_stripoffset[strip] != 0) {
+			/*
+			 * Prevent overlapping of the data chunks. We need
+                         * this to enable in place updating of the compressed
+                         * images. Larger blocks will be moved at the end of
+                         * the file without any optimization of the spare
+                         * space, so such scheme is not too much effective.
+			 */
+			tstrip_t i;
+			for (i = 0; i < td->td_stripsperimage; i++) {
+				if (td->td_stripoffset[i] > 
+					td->td_stripoffset[strip]
+				    && td->td_stripoffset[i] <
+					td->td_stripoffset[strip] + cc) {
+					td->td_stripoffset[strip] =
+						TIFFSeekFile(tif, (toff_t) 0,
+							     SEEK_END);
+				}
+			}
+
 			if (!SeekOK(tif, td->td_stripoffset[strip])) {
 				TIFFError(module,
 					  "%s: Seek error at scanline %lu",
@@ -644,6 +647,7 @@ TIFFAppendToStrip(TIFF* tif, tstrip_t strip, tidata_t data, tsize_t cc)
 			    TIFFSeekFile(tif, (toff_t) 0, SEEK_END);
 		tif->tif_curoff = td->td_stripoffset[strip];
 	}
+
 	if (!WriteOK(tif, data, cc)) {
 		TIFFError(module, "%s: Write error at scanline %lu",
 		    tif->tif_name, (u_long) tif->tif_row);