add vips_foreign_save_buffer()

ChangeLog

@@ -23,7 +23,7 @@
 - support 16-bit palette TIFFs, plus palette TIFFs can have an alpha
 - add ".vips" as an alternative suffix for vips files
 - added vips_tiffload_buffer()
-- added vips_foreign_load_buffer()
+- added vips_foreign_load_buffer(), vips_foreign_save_buffer()
 
 6/3/14 started 7.38.6
 - grey ramp minimum was wrong

TODO

@@ -1,23 +1,21 @@
-- need to be able to select savers by suffix, and set options
+- need to be able to set options for buffer save from the suffix
 
-  eg.
+  vips_foreign_save_buffer() needs
 
-	  vips_foreign_save_buffer( VipsImage *in, void **buf, size_t *len, 
+  - split suffix for match against class->suffs
-		const char *format, ... )
 
-  format can be
+  - set options from suffix
 
-  	.jpg
+  no. 2 needs something like:
-	.jpg[Q=80]
 
-  opt can be passed in the ... as well, overriding things set in the format
+  vips_object_set_options_from_string( object, "[a=12,b=13]" );
 
+  perhaps with the outermost brackets optional?
 
-  ... but foreign_class->suffs is set for eg. jpegsave_file and is how we pick
+  maybe vips_object_set_from_string()?
-  out savers from destination filenames, what can we use to pick buffer
+
-  savers?
+  read object.c and see how close we are to this model now
 
-  need some new class member to do the lookup on? .suffs_buffer?
 
 - use this for dzsave_buffer 
 
@@ -27,6 +25,11 @@
 
   deprecate this thing and stop ':' split
 
+  vips_foreign_find_save() should split on [], there's something to find the
+  start of the rightmost [] pair, use that
+
+  see also vips_foreign_find_save_buffer()
+
 
   
 

libvips/foreign/foreign.c

@@ -1063,7 +1063,7 @@ vips_foreign_find_save_sub( VipsForeignSaveClass *save_class,
  * @filename may not contain embedded options. See
  * vips_foreign_find_save_options() if your filename may have options in.
  *
- * See also: vips_foreign_write().
+ * See also: vips_foreign_save().
  *
  * Returns: the name of an operation on success, %NULL on error
  */
@@ -1085,6 +1085,55 @@ vips_foreign_find_save( const char *filename )
 	return( G_OBJECT_CLASS_NAME( save_class ) );
 }
 
+/* Can we write this buffer with this file type?
+ */
+static void *
+vips_foreign_find_save_buffer_sub( VipsForeignSaveClass *save_class, 
+	const char *suffix )
+{
+	VipsObjectClass *class = VIPS_OBJECT_CLASS( save_class );
+	VipsForeignClass *class = VIPS_FOREIGN_CLASS( save_class );
+
+	if( class->suffs &&
+		vips_ispostfix( class->nickname, "_buffer" ) &&
+		vips_filename_suffix_match( suffix, class->suffs ) )
+		return( save_class );
+
+	return( NULL );
+}
+
+/**
+ * vips_foreign_find_save_buffer:
+ * @suffix: name to find a saver for
+ *
+ * Searches for an operation you could use to write to a buffer in @suffix
+ * format. 
+ *
+ * @filename may not contain embedded options. See
+ * vips_foreign_find_save_options() if your filename may have options in.
+ *
+ * See also: vips_foreign_save_buffer().
+ *
+ * Returns: the name of an operation on success, %NULL on error
+ */
+const char *
+vips_foreign_find_save_buffer( const char *suffix )
+{
+	VipsForeignSaveClass *save_class;
+
+	if( !(save_class = (VipsForeignSaveClass *) vips_foreign_map( 
+		"VipsForeignSave",
+		(VipsSListMap2Fn) vips_foreign_find_save_sub, 
+		(void *) suffix, NULL )) ) {
+		vips_error( "VipsForeignSave",
+			_( "\"%s\" is not a known file format" ), suffix );
+
+		return( NULL );
+	}
+
+	return( G_OBJECT_CLASS_NAME( save_class ) );
+}
+
 /**
  * vips_foreign_find_save_options:
  * @filename: name to find a saver for
@@ -1092,7 +1141,7 @@ vips_foreign_find_save( const char *filename )
  * Searches for an operation you could use to write to @filename.
  *
  * @filename may contain embedded options. See
- * vips_foreign_find_save() if your filename does not options in.
+ * vips_foreign_find_save() if your filename does not have options in.
  *
  * See also: vips_foreign_write().
  *
@@ -1583,6 +1632,47 @@ vips_foreign_save( VipsImage *in, const char *filename, ... )
 	return( result );
 }
 
+/**
+ * vips_foreign_save_buffer:
+ * @in: image to write
+ * @suffix: format to write 
+ * @buf: return buffer start here
+ * @len: return buffer length here
+ * @...: %NULL-terminated list of optional named arguments
+ *
+ * Saves @in to @filename using the saver recommended by
+ * vips_foreign_find_save(). Options are not in @suffix but must be given
+ * as a NULL-terminated list of name-value pairs.
+ *
+ * See also: vips_foreign_load_buffer().
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int
+vips_foreign_save_buffer( VipsImage *in, 
+	const char *suffix, void **buf, size_t *len, 
+	... )
+{
+	const char *operation;
+	va_list ap;
+	int result;
+
+	if( !(operation = vips_foreign_find_save_buffer( suffix )) )
+		return( -1 );
+
+	/* We don't take a copy of the data or free it.
+	 */
+	area = vips_area_new_blob( NULL, buf, len );
+
+	va_start( ap, filename );
+	result = vips_call_split( operation, ap, in, area );
+	va_end( ap );
+
+	vips_area_unref( area );
+
+	return( result );
+}
+
 /**
  * vips_foreign_load_options:
  * @filename: file to load

libvips/include/vips/foreign.h

@@ -308,14 +308,13 @@ typedef struct _VipsForeignSaveClass {
 GType vips_foreign_save_get_type( void );
 
 const char *vips_foreign_find_save( const char *filename );
+const char * vips_foreign_find_save_buffer( const char *suffix );
 const char *vips_foreign_find_save_options( const char *filename );
 
 /* Read/write an image convenience functions.
  */
 int vips_foreign_load( const char *filename, VipsImage **out, ... )
 	__attribute__((sentinel));
-int vips_foreign_load_buffer( void *buf, size_t len, VipsImage **out, ... )
-	__attribute__((sentinel));
 int vips_foreign_save( VipsImage *in, const char *filename, ... )
 	__attribute__((sentinel));
 
@@ -324,6 +323,12 @@ int vips_foreign_load_options( const char *filename, VipsImage **out, ... )
 int vips_foreign_save_options( VipsImage *in, const char *filename, ... )
 	__attribute__((sentinel));
 
+int vips_foreign_load_buffer( void *buf, size_t len, VipsImage **out, ... )
+	__attribute__((sentinel));
+int vips_foreign_save_buffer( VipsImage *in, 
+	const char *suffix, void **buf, size_t *len, ... )
+	__attribute__((sentinel));
+
 int vips_openslideload( const char *filename, VipsImage **out, ... )
 	__attribute__((sentinel));