support many Radiance readers active at once

we had some globals for the Rad reader state, whcih was fine with the
old reader, but with the new sequential one you can have several active
at once

ChangeLog

@@ -3,6 +3,7 @@
 - falsecolour was not working for some image types
 - foreign memory buffer images did not have the right dhint, broke
   command-line falsecolour on sequential images
+- support many Radiance readers active at once
 
 19/1/14 started 7.38.1
 - bump soname, thanks benjamin

TODO

@@ -1,21 +1,3 @@
-- shrink does not auto unpack labq or rad, should it?
-
-- others .. differences in:
-
-grep -l CODING_LABQ */*.c
-conversion/join.c
-conversion/msb.c
-inplace/im_draw_mask.c
-resample/shrink.c
-
-grep -l CODING_RAD */*.c
-conversion/embed.c
-inplace/flood.c
-inplace/im_draw_image.c
-
-
-
-
 
 - need to do mosaicing and inplace, plus im_label_regions in morph
 

libvips/foreign/jpeg2vips.c

@@ -894,7 +894,7 @@ read_jpeg_generate( VipsRegion *or,
 	printf( "read_jpeg_generate: line %d, %d rows\n", 
 		r->top, r->height );
 #endif /*DEBUG*/
-	
+
 	VIPS_GATE_START( "read_jpeg_generate: work" );
 
 	/* We're inside a tilecache where tiles are the full image width, so

libvips/foreign/radiance.c

@@ -12,6 +12,9 @@
  * 	- support sequential read
  * 5/11/13
  * 	- rewritten scanline encode and decode, now much faster
+ * 23/1/14
+ * 	- put the reader globals into a struct so we can have many active
+ * 	  readers
  */
 
 /*
@@ -617,38 +620,57 @@ register RESOLU  *rp;
 #define BUFFER_SIZE (4096)
 #define BUFFER_MARGIN (256)
 
-static unsigned char buffer[BUFFER_SIZE + BUFFER_MARGIN];
-static int buffer_length = 0;
-static int buffer_position = 0;
-static FILE *buffer_fp = NULL;
+/* Read from a FILE with a rolling memory buffer ... this lets us reduce the
+ * number of fgetc() and gives us some very quick readahead.
+ */
 
-static void
-buffer_init( FILE *fp )
+typedef struct _Buffer { 
+	unsigned char text[BUFFER_SIZE + BUFFER_MARGIN];
+	int length;
+	int position;
+	FILE *fp;
+} Buffer; 
+
+static Buffer *
+buffer_new( FILE *fp )
 {
-	buffer_length = 0;
-	buffer_position = 0;
-	buffer_fp = fp;
+	Buffer *buffer = g_new0( Buffer, 1 );
+
+	buffer->length = 0;
+	buffer->position = 0;
+	buffer->fp = fp;
+
+	return( buffer ); 
 }
 
+static void
+buffer_free( Buffer *buffer )
+{
+	g_free( buffer ); 
+}
+
+/* Make sure there are at least @require bytes of readahead available.
+ */
 static int
-buffer_need( int require )
+buffer_need( Buffer *buffer, int require )
 {
 	int remaining;
 
 	g_assert( require < BUFFER_MARGIN ); 
 
-	remaining = buffer_length - buffer_position;
+	remaining = buffer->length - buffer->position;
 	if( remaining < require ) {
 		size_t len;
 
-		memcpy( buffer, buffer + buffer_position, remaining ); 
-		buffer_position = 0;
-		buffer_length = remaining;
+		memcpy( buffer->text, 
+			buffer->text + buffer->position, remaining ); 
+		buffer->position = 0;
+		buffer->length = remaining;
 
-		len = fread( buffer + buffer_length, 1, BUFFER_SIZE, 
-			buffer_fp );
-		buffer_length += len;
-		remaining = buffer_length - buffer_position;
+		len = fread( buffer->text + buffer->length, 
+			1, BUFFER_SIZE, buffer->fp );
+		buffer->length += len;
+		remaining = buffer->length - buffer->position;
 
 		if( remaining < require ) {
 			vips_error( "rad2vips", "%s", _( "end of file" ) ); 
@@ -659,26 +681,26 @@ buffer_need( int require )
 	return( 0 );
 }
 
-#define BUFFER_FETCH (buffer[buffer_position++])
-#define BUFFER_PEEK (buffer[buffer_position])
+#define BUFFER_FETCH(B) ((B)->text[(B)->position++])
+#define BUFFER_PEEK(B) ((B)->text[(B)->position])
 
 /* Read a single scanlne, encoded in the old style.
  */
 static int
-scanline_read_old( COLR *scanline, int width )
+scanline_read_old( Buffer *buffer, COLR *scanline, int width )
 {
 	int rshift;
 
 	rshift = 0;
 	
 	while( width > 0 ) {
-		if( buffer_need( 4 ) )
+		if( buffer_need( buffer, 4 ) )
 			return( -1 ); 
 
-		scanline[0][RED] = BUFFER_FETCH;
-		scanline[0][GRN] = BUFFER_FETCH;
-		scanline[0][BLU] = BUFFER_FETCH;
-		scanline[0][EXP] = BUFFER_FETCH;
+		scanline[0][RED] = BUFFER_FETCH( buffer );
+		scanline[0][GRN] = BUFFER_FETCH( buffer );
+		scanline[0][BLU] = BUFFER_FETCH( buffer );
+		scanline[0][EXP] = BUFFER_FETCH( buffer );
 
 		if( scanline[0][RED] == 1 &&
 			scanline[0][GRN] == 1 &&
@@ -706,7 +728,7 @@ scanline_read_old( COLR *scanline, int width )
 /* Read a single encoded scanline.
  */
 static int
-scanline_read( COLR *scanline, int width )
+scanline_read( Buffer *buffer, COLR *scanline, int width )
 {
 	int i, j;
 
@@ -714,21 +736,21 @@ scanline_read( COLR *scanline, int width )
 	 */
 	if( width < MINELEN ||
 		width > MAXELEN )
-		return( scanline_read_old( scanline, width ) );
+		return( scanline_read_old( buffer, scanline, width ) );
 
-	if( buffer_need( 4 ) )
+	if( buffer_need( buffer, 4 ) )
 		return( -1 ); 
 
-	if( BUFFER_PEEK != 2 ) 
-		return( scanline_read_old( scanline, width ) );
+	if( BUFFER_PEEK( buffer ) != 2 ) 
+		return( scanline_read_old( buffer, scanline, width ) );
 
-	scanline[0][RED] = BUFFER_FETCH;
-	scanline[0][GRN] = BUFFER_FETCH;
-	scanline[0][BLU] = BUFFER_FETCH;
-	scanline[0][EXP] = BUFFER_FETCH;
+	scanline[0][RED] = BUFFER_FETCH( buffer );
+	scanline[0][GRN] = BUFFER_FETCH( buffer );
+	scanline[0][BLU] = BUFFER_FETCH( buffer );
+	scanline[0][EXP] = BUFFER_FETCH( buffer );
 	if( scanline[0][GRN] != 2 || 
 		scanline[0][BLU] & 128 ) 
-		return( scanline_read_old( scanline + 1, width - 1 ) );
+		return( scanline_read_old( buffer, scanline + 1, width - 1 ) );
 
 	if( ((scanline[0][BLU] << 8) | scanline[0][EXP]) != width ) {
 		vips_error( "rad2vips", "%s", _( "scanline length mismatch" ) );
@@ -740,10 +762,10 @@ scanline_read( COLR *scanline, int width )
 			int code, len;
 			gboolean run;
 
-			if( buffer_need( 2 ) )
+			if( buffer_need( buffer, 2 ) )
 				return( -1 ); 
 
-			code = BUFFER_FETCH; 
+			code = BUFFER_FETCH( buffer ); 
 			run = code > 128;
 			len = run ? code & 127 : code; 
 
@@ -755,15 +777,16 @@ scanline_read( COLR *scanline, int width )
 			if( run ) { 
 				int val;
 
-				val = BUFFER_FETCH; 
+				val = BUFFER_FETCH( buffer ); 
 				while( len-- )
 					scanline[j++][i] = val;
 			} 
 			else {
-				if( buffer_need( len ) )
+				if( buffer_need( buffer, len ) )
 					return( -1 ); 
 				while( len-- ) 
-					scanline[j++][i] = BUFFER_FETCH;
+					scanline[j++][i] = 
+						BUFFER_FETCH( buffer );
 			}
 		}
 
@@ -861,6 +884,7 @@ typedef struct {
 	double aspect;
 	RGBPRIMS prims;
 	RESOLU rs;
+	Buffer *buffer; 
 } Read;
 
 int
@@ -888,7 +912,7 @@ read_destroy( VipsObject *object, Read *read )
 {
 	VIPS_FREE( read->filename );
 	VIPS_FREEF( fclose, read->fin );
-	buffer_init( NULL );
+	VIPS_FREEF( buffer_free, read->buffer );
 }
 
 static Read *
@@ -920,9 +944,9 @@ read_new( const char *filename, VipsImage *out )
 	g_signal_connect( out, "close", 
 		G_CALLBACK( read_destroy ), read );
 
-	if( !(read->fin = vips__file_open_read( filename, NULL, FALSE )) ) 
+	if( !(read->fin = vips__file_open_read( filename, NULL, FALSE )) || 
+		!(read->buffer = buffer_new( read->fin )) )
 		return( NULL );
-	buffer_init( read->fin );
 
 	return( read );
 }
@@ -1037,24 +1061,30 @@ rad2vips_generate( VipsRegion *or,
 	void *seq, void *a, void *b, gboolean *stop )
 {
         VipsRect *r = &or->valid;
+	Read *read = (Read *) a; 
 
 	int y;
 
 #ifdef DEBUG
-	printf( "rad2vips_get_data\n" );
+	printf( "rad2vips_generate: line %d, %d rows\n", 
+		r->top, r->height );
 #endif /*DEBUG*/
 
+	VIPS_GATE_START( "rad2vips_generate: work" );
+
 	for( y = 0; y < r->height; y++ ) {
 		COLR *buf = (COLR *) 
 			VIPS_REGION_ADDR( or, 0, r->top + y );
 
-		if( scanline_read( buf, or->im->Xsize ) ) {
+		if( scanline_read( read->buffer, buf, or->im->Xsize ) ) {
 			vips_error( "rad2vips", 
 				_( "read error line %d" ), r->top + y );
 			return( -1 );
 		}
 	}
 
+	VIPS_GATE_STOP( "rad2vips_generate: work" );
+
 	return( 0 );
 }