turn format/*jpeg* into stubs

the old im_vips2jpeg.c and im_jpeg2vips.c are now just stubs calling the
new foreign/ things

TODO

@@ -10,6 +10,15 @@
 
 
 
+- "header" with more than one arg should put the filename before each printed
+  line so eg. 
+  
+  	$ header *.jpg | grep -i prof
+
+  works
+
+
+
 - make compat wrappers for old im_jpeg2vips() and im_vips2jpeg()
 
   make sure we are using the operation cache for jpegload

libvips/deprecated/lazy.c

@@ -217,13 +217,18 @@ vips_image_open_lazy( VipsImage *image,
 		return( -1 );
 	vips_demand_hint( image, VIPS_DEMAND_STYLE_THINSTRIP, NULL );
 
-	/* Then 'start' creates the real image and 'gen' paints 'out' with 
+	/* If there's no load function, assume header has done everything
-	 * pixels from the real image on demand.
+	 * already.
 	 */
-	if( vips_image_generate( image, 
+	if( format->load ) {
-		open_lazy_start, open_lazy_generate, vips_stop_one, 
+		/* Then 'start' creates the real image and 'gen' paints 'image' 
-		lazy, NULL ) )
+		 * with pixels from the real image on demand.
-		return( -1 );
+		 */
+		if( vips_image_generate( image, 
+			open_lazy_start, open_lazy_generate, vips_stop_one, 
+			lazy, NULL ) )
+			return( -1 );
+	}
 
 	return( 0 );
 }

libvips/foreign/jpegload.c

@@ -235,6 +235,68 @@ vips_foreign_load_jpeg_file_init( VipsForeignLoadJpegFile *file )
 {
 }
 
+/**
+ * vips_jpegload:
+ * @filename: file to load
+ * @out: decompressed image
+ * @flags: image flags
+ * @shrink: shrink by this much on load
+ * @fail: fail on warnings
+ *
+ * Read a JPEG file into a VIPS image. It can read most 8-bit JPEG images, 
+ * including CMYK and YCbCr.
+ *
+ * @shrink means shrink by this integer factor during load.  Possible values 
+ * are 1, 2, 4 and 8. Shrinking during read is very much faster than 
+ * decompressing the whole image and then shrinking later.
+ *
+ * Setting @fail to true makes the JPEG reader fail on any warnings. 
+ * This can be useful for detecting truncated files, for example. Normally 
+ * reading these produces a warning, but no fatal error.  
+ *
+ * Example:
+ *
+ * |[
+ * vips_jpegload( "fred.jpg", &out,
+ * 	"shrink", 8,
+ * 	"fail", TRUE,
+ * 	NULL );
+ * ]|
+ *
+ * Any embedded ICC profiles are ignored: you always just get the RGB from 
+ * the file. Instead, the embedded profile will be attached to the image as 
+ * metadata.  You need to use something like im_icc_import() to get CIE 
+ * values from the file. Any EXIF data is also attached as VIPS metadata.
+ *
+ * The int metadata item "jpeg-multiscan" is set to the result of 
+ * jpeg_has_multiple_scans(). Interlaced jpeg images need a large amount of
+ * memory to load, so this field gives callers a chance to handle these
+ * images differently.
+ *
+ * The EXIF thumbnail, if present, is attached to the image as 
+ * "jpeg-thumbnail-data". See vips_image_get_blob().
+ *
+ * This function only reads the image header and does not decompress any pixel
+ * data. Decompression only occurs when pixels are accessed by some other
+ * function.
+ *
+ * See also: vips_jpegload_buffer(), vips_image_new_from_file().
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+vips_jpegload( const char *filename, VipsImage **out, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, out );
+	result = vips_call_split( "jpegload", ap, filename, out );
+	va_end( ap );
+
+	return( result );
+}
+
 typedef struct _VipsForeignLoadJpegBuffer {
 	VipsForeignLoadJpeg parent_object;
 
@@ -304,3 +366,43 @@ static void
 vips_foreign_load_jpeg_buffer_init( VipsForeignLoadJpegBuffer *buffer )
 {
 }
+
+
+/**
+ * vips_jpegload_buffer:
+ * @buf: memory area to load
+ * @len: size of memory area
+ * @out: image to write
+ *
+ * Read a JPEG-formatted memory block into a VIPS image. It can read most 
+ * 8-bit JPEG images, including CMYK and YCbCr.
+ *
+ * This function is handy for processing JPEG image thumbnails.
+ *
+ * Caution: on return only the header will have been read, the pixel data is
+ * not decompressed until the first pixel is read. Therefore you must not free
+ * @buf until you have read pixel data from @out.
+ *
+ * See also: vips_jpegload().
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+vips_jpegload_buffer( void *buf, size_t len, VipsImage **out, ... )
+{
+	va_list ap;
+	VipsArea *area;
+	int result;
+
+	/* We don't take a copy of the data or free it.
+	 */
+	area = vips_area_new_blob( NULL, buf, len );
+
+	va_start( ap, out );
+	result = vips_call_split( "jpegload_buffer", ap, area, out );
+	va_end( ap );
+
+	vips_area_unref( area );
+
+	return( result );
+}

libvips/foreign/jpegsave.c

@@ -200,6 +200,47 @@ vips_foreign_save_jpeg_file_init( VipsForeignSaveJpegFile *file )
 {
 }
 
+
+/**
+ * vips_jpegsave:
+ * @in: image to save 
+ * @filename: file to write to 
+ * @Q: quality factor
+ * @profile: attach this ICC profile
+ *
+ * Write a VIPS image to a file as JPEG.
+ *
+ * Use @Q to set the JPEG compression factor. Default 75.
+ *
+ * Use @profile to give the filename of a profile to be em,bedded in the JPEG.
+ * This does not affect the pixels which are written, just the way 
+ * they are tagged. You can use the special string "none" to mean 
+ * "don't attach a profile".
+ *
+ * If no profile is specified and the VIPS header 
+ * contains an ICC profile named VIPS_META_ICC_NAME ("icc-profile-data"), the
+ * profile from the VIPS header will be attached.
+ *
+ * The image is automatically converted to RGB, Monochrome or CMYK before 
+ * saving. Any metadata attached to the image is saved as EXIF, if possible.
+ *
+ * See also: vips_jpegsave_buffer(), vips_image_write_file().
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+vips_jpegsave( VipsImage *in, const char *filename, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, filename );
+	result = vips_call_split( "jpegsave", ap, in, filename );
+	va_end( ap );
+
+	return( result );
+}
+
 typedef struct _VipsForeignSaveJpegBuffer {
 	VipsForeignSaveJpeg parent_object;
 
@@ -267,6 +308,48 @@ vips_foreign_save_jpeg_buffer_init( VipsForeignSaveJpegBuffer *file )
 {
 }
 
+
+/**
+ * vips_jpegsave_buffer:
+ * @in: image to save 
+ * @buf: return output buffer here
+ * @len: return output length here
+ * @Q: JPEG quality factor
+ * @profile: attach this ICC profile
+ *
+ * As vips_jpegsave(), but save to a memory buffer. 
+ *
+ * The address of the buffer is returned in @obuf, the length of the buffer in
+ * @olen. You are responsible for freeing the buffer with g_free() when you
+ * are done with it.
+ *
+ * See also: vips_jpegsave(), vips_image_write_to_file().
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+vips_jpegsave_buffer( VipsImage *in, void **buf, size_t *len, ... )
+{
+	va_list ap;
+	VipsArea *area;
+	int result;
+
+	va_start( ap, len );
+	result = vips_call_split( "jpegsave_buffer", ap, in, &area );
+	va_end( ap );
+
+	if( buf ) {
+		*buf = area->data;
+		area->free_fn = NULL;
+	}
+	if( buf ) 
+		*len = area->length;
+
+	vips_area_unref( area );
+
+	return( result );
+}
+
 typedef struct _VipsForeignSaveJpegMime {
 	VipsForeignSaveJpeg parent_object;
 
@@ -323,3 +406,28 @@ static void
 vips_foreign_save_jpeg_mime_init( VipsForeignSaveJpegMime *mime )
 {
 }
+
+/**
+ * vips_jpegsave_mime:
+ * @in: image to save 
+ * @Q: JPEG quality factor
+ * @profile: attach this ICC profile
+ *
+ * As vips_jpegsave(), but save as a mime jpeg on stdout.
+ *
+ * See also: vips_jpegsave(), vips_image_write_to_file().
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int
+vips_jpegsave_mime( VipsImage *in, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, in );
+	result = vips_call_split( "jpegsave_mime", ap, in );
+	va_end( ap );
+
+	return( result );
+}

libvips/include/vips/foreign.h

@@ -229,6 +229,13 @@ int vips_foreign_write( VipsImage *in, const char *filename, ... );
 
 void vips_foreign_operation_init( void );
 
+int vips_jpegload( const char *filename, VipsImage **out, ... );
+int vips_jpegload_buffer( void *buf, size_t len, VipsImage **out, ... );
+
+int vips_jpegsave( VipsImage *in, const char *filename, ... );
+int vips_jpegsave_buffer( VipsImage *in, void **buf, size_t *len, ... );
+int vips_jpegsave_mime( VipsImage *in, ... );
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/

libvips/iofuncs/cache.c

@@ -147,22 +147,22 @@ vips_value_hash( GParamSpec *pspec, GValue *value )
 	else if( generic == G_TYPE_PARAM_STRING ) {
 		const char *s = g_value_get_string( value );
 
-		return( g_str_hash( s ) );
+		return( s ? g_str_hash( s ) : 0 );
 	}
 	else if( generic == G_TYPE_PARAM_BOXED ) {
 		void *p = g_value_get_boxed( value );
 
-		return( g_direct_hash( p ) );
+		return( p ? g_direct_hash( p ) : 0 );
 	}
 	else if( generic == G_TYPE_PARAM_POINTER ) {
 		void *p = g_value_get_pointer( value );
 
-		return( g_direct_hash( p ) );
+		return( p ? g_direct_hash( p ) : 0 );
 	}
 	else if( generic == G_TYPE_PARAM_OBJECT ) {
 		void *p = g_value_get_object( value );
 
-		return( g_direct_hash( p ) );
+		return( p ? g_direct_hash( p ) : 0 );
 	}
 	else {
 		/* Fallback: convert to a string and hash that.