add streamo_steal

and start converting some old dbuf code

libvips/foreign/svgload.c

@@ -268,8 +268,7 @@ vips_g_input_stream_skip( GInputStream *stream, gsize count,
 	GCancellable *cancellable, GError **error )
 {
 	VipsStreami *streami;
-	goffset start;
-	goffset end;
+	gssize position;
 
 	streami = VIPS_G_INPUT_STREAM( stream )->streami;
 
@@ -278,8 +277,8 @@ vips_g_input_stream_skip( GInputStream *stream, gsize count,
 	if( g_cancellable_set_error_if_cancelled( cancellable, error ) )
 		return( -1 );
 
-	start = vips_streami_seek( streami, count, SEEK_CUR );
-	if( start == -1 ) {
+	position = vips_streami_seek( streami, count, SEEK_CUR );
+	if( position == -1 ) {
 		g_set_error( error, G_IO_ERROR,
 			G_IO_ERROR_FAILED,
 			_( "Error while seeking: %s" ),
@@ -287,7 +286,7 @@ vips_g_input_stream_skip( GInputStream *stream, gsize count,
 		return( -1 );
 	}
 
-	return( count );
+	return( position );
 }
 
 static gboolean

libvips/include/vips/stream.h

@@ -241,6 +241,10 @@ typedef struct _VipsStreamo {
 
 	/*< private >*/
 
+	/* The stream has been finished and can no longer be written.
+	 */
+	gboolean finished;
+
 	/* Write memory output here.
 	 */
 	GByteArray *memory;
@@ -278,16 +282,19 @@ VipsStreamo *vips_streamo_new_to_filename( const char *filename );
 VipsStreamo *vips_streamo_new_to_memory( void );
 int vips_streamo_write( VipsStreamo *streamo, const void *data, size_t length );
 void vips_streamo_finish( VipsStreamo *streamo );
+unsigned char *vips_streamo_steal( VipsStreamo *streamo, size_t *length );
+char *vips_streamo_steal_text( VipsStreamo *streamo );
 
 int vips_streamo_putc( VipsStreamo *streamo, int ch );
 #define VIPS_STREAMO_PUTC( S, C ) ( \
-	(S)->write_point <= VIPS_STREAMO_BUFFER_SIZE ? \
+	(S)->write_point < VIPS_STREAMO_BUFFER_SIZE ? \
 	((S)->output_buffer[(S)->write_point++] = (C), 0) : \
 	vips_streamo_putc( (S), (C) ) \
 )
 int vips_streamo_writes( VipsStreamo *streamo, const char *str );
 int vips_streamo_writef( VipsStreamo *streamo, const char *fmt, ... )
 	__attribute__((format(printf, 2, 3)));
+int vips_streamo_write_amp( VipsStreamo *streamo, const char *str );
 
 #ifdef __cplusplus
 }

libvips/iofuncs/streamo.c

@@ -293,6 +293,9 @@ vips_streamo_write_unbuffered( VipsStreamo *streamo,
 {
 	VipsStreamoClass *class = VIPS_STREAMO_GET_CLASS( streamo );
 
+	if( streamo->finished )
+		return( 0 );
+
 	if( streamo->memory ) 
 		g_byte_array_append( streamo->memory, data, length );
 	else 
@@ -375,7 +378,10 @@ vips_streamo_write( VipsStreamo *streamo, const void *buffer, size_t length )
  * @buffer: bytes to write
  * @length: length of @buffer in bytes
  *
- * Call this at the end of write to make the stream do any cleaning up.
+ * Call this at the end of write to make the stream do any cleaning up. You
+ * can call it many times. 
+ *
+ * After a streamo has been finished, further writes will do nothing.
  */
 void
 vips_streamo_finish( VipsStreamo *streamo )
@@ -384,6 +390,9 @@ vips_streamo_finish( VipsStreamo *streamo )
 
 	VIPS_DEBUG_MSG( "vips_streamo_finish:\n" );
 
+	if( streamo->finished )
+		return;
+
 	(void) vips_streamo_flush( streamo );
 
 	/* Move the stream buffer into the blob so it can be read out.
@@ -400,6 +409,69 @@ vips_streamo_finish( VipsStreamo *streamo )
 	}
 	else
 		class->finish( streamo );
+
+	streamo->finished = TRUE;
+}
+
+/**
+ * vips_streamo_steal: 
+ * @streamo: output stream to operate on
+ * @length: return number of bytes of data
+ *
+ * Memory streams only (see vips_streamo_new_to_memory()). Steal all data
+ * written to the stream so far, and finish it.
+ *
+ * You must free the returned pointer with g_free().
+ *
+ * The data is NOT automatically null-terminated. vips_streamo_putc() a '\0' 
+ * before calling this to get a null-terminated string.
+ *
+ * Returns: (array length=length) (element-type guint8) (transfer full): the 
+ * data
+ */
+unsigned char *
+vips_streamo_steal( VipsStreamo *streamo, size_t *length )
+{
+	unsigned char *data;
+
+	(void) vips_streamo_flush( streamo );
+
+	if( !streamo->memory ||
+		streamo->finished ) {
+		if( length )
+			*length = streamo->memory->len;
+
+		return( NULL );
+	}
+
+	if( length )
+		*length = streamo->memory->len;
+	data = g_byte_array_free( streamo->memory, FALSE );
+	streamo->memory = NULL;
+
+	/* We must have a valid byte array or finish will fail.
+	 */
+	streamo->memory = g_byte_array_new();
+
+	vips_streamo_finish( streamo );
+
+	return( data );
+}
+
+/**
+ * vips_streamo_steal_text: 
+ * @streamo: output stream to operate on
+ *
+ * As vips_streamo_steal_text(), but return a null-terminated string.
+ *
+ * Returns: (transfer full): stream contents as a null-terminated string.
+ */
+char *
+vips_streamo_steal_text( VipsStreamo *streamo )
+{
+	vips_streamo_putc( streamo, '\0' );  
+
+	return( (char *) vips_streamo_steal( streamo, NULL ) ); 
 }
 
 /**
@@ -417,7 +489,7 @@ vips_streamo_putc( VipsStreamo *streamo, int ch )
 {
 	VIPS_DEBUG_MSG( "vips_streamo_putc: %d\n", ch );
 
-	if( streamo->write_point > VIPS_STREAMO_BUFFER_SIZE && 
+	if( streamo->write_point >= VIPS_STREAMO_BUFFER_SIZE && 
 		vips_streamo_flush( streamo ) )
 		return( -1 );
 
@@ -504,27 +576,24 @@ vips_streamo_write_amp( VipsStreamo *streamo, const char *str )
 			 * control characters, so we can use them -- thanks
 			 * electroly.
 			 */
-			if( !vips_streamo_writef( streamo, 
+			if( vips_streamo_writef( streamo, 
 				"&#x%04x;", 0x2400 + *p ) )
 				return( -1 );	
 		}
 		else if( *p == '<' ) {
-			if( !vips_streamo_write( streamo, 
-				(guchar *) "&lt;", 4 ) )
+			if( vips_streamo_writes( streamo, "&lt;" ) )
 				return( -1 );
 		}
 		else if( *p == '>' ) {
-			if( !vips_streamo_write( streamo, 
-				(guchar *) "&gt;", 4 ) )
+			if( vips_streamo_writes( streamo, "&gt;" ) )
 				return( -1 );
 		}
 		else if( *p == '&' ) {
-			if( !vips_streamo_write( streamo, 
-				(guchar *) "&amp;", 5 ) )
+			if( vips_streamo_writes( streamo, "&amp;" ) )
 				return( -1 );
 		}
 		else  {
-			if( !vips_streamo_putc( streamo, *p ) )
+			if( VIPS_STREAMO_PUTC( streamo, *p ) )
 				return( -1 );
 		}
 

libvips/iofuncs/vips.c

@@ -912,7 +912,7 @@ static void *
 vips__xml_properties_meta( VipsImage *image, 
 	const char *field, GValue *value, void *a )
 {
-	VipsDbuf *dbuf = (VipsDbuf *) a;
+	VipsStreamo *streamo = (VipsStreamo *) a;
 	GType type = G_VALUE_TYPE( value );
 
 	const char *str;
@@ -928,19 +928,19 @@ vips__xml_properties_meta( VipsImage *image,
 		if( !g_value_transform( value, &save_value ) ) {
 			vips_error( "VipsImage", "%s", 
 				_( "error transforming to save format" ) );
-			return( dbuf );
+			return( streamo );
 		}
 		str = vips_value_get_save_string( &save_value );
 
-		vips_dbuf_writef( dbuf, "    <property>\n" );  
-		vips_dbuf_writef( dbuf, "      <name>" ); 
-		vips_dbuf_write_amp( dbuf, field );
-		vips_dbuf_writef( dbuf, "</name>\n" ); 
-		vips_dbuf_writef( dbuf, "      <value type=\"%s\">",
+		vips_streamo_writef( streamo, "    <property>\n" );  
+		vips_streamo_writef( streamo, "      <name>" ); 
+		vips_streamo_write_amp( streamo, field );
+		vips_streamo_writef( streamo, "</name>\n" ); 
+		vips_streamo_writef( streamo, "      <value type=\"%s\">",
 			g_type_name( type ) );  
-		vips_dbuf_write_amp( dbuf, str );
-		vips_dbuf_writef( dbuf, "</value>\n" ); 
-		vips_dbuf_writef( dbuf, "    </property>\n" );  
+		vips_streamo_write_amp( streamo, str );
+		vips_streamo_writef( streamo, "</value>\n" ); 
+		vips_streamo_writef( streamo, "    </property>\n" );  
 
 		g_value_unset( &save_value );
 	}
@@ -954,31 +954,31 @@ vips__xml_properties_meta( VipsImage *image,
 char *
 vips__xml_properties( VipsImage *image )
 {
-	VipsDbuf dbuf;
+	VipsStreamo *streamo;
 	char *date;
 
 	date = vips__get_iso8601();
 
-	vips_dbuf_init( &dbuf ); 
-	vips_dbuf_writef( &dbuf, "<?xml version=\"1.0\"?>\n" ); 
-	vips_dbuf_writef( &dbuf, "<image xmlns=\"%s/dzsave\" "
+	streamo = vips_streamo_new_to_memory();
+	vips_streamo_writef( streamo, "<?xml version=\"1.0\"?>\n" ); 
+	vips_streamo_writef( streamo, "<image xmlns=\"%s/dzsave\" "
 		"date=\"%s\" version=\"%d.%d.%d\">\n", 
 		NAMESPACE_URI, 
 		date, 
 		VIPS_MAJOR_VERSION, VIPS_MINOR_VERSION, VIPS_MICRO_VERSION );
-	vips_dbuf_writef( &dbuf, "  <properties>\n" );  
+	vips_streamo_writef( streamo, "  <properties>\n" );  
 
 	g_free( date ); 
 
-	if( vips_image_map( image, vips__xml_properties_meta, &dbuf ) ) {
-		vips_dbuf_destroy( &dbuf );
+	if( vips_image_map( image, vips__xml_properties_meta, streamo ) ) {
+		VIPS_UNREF( streamo );
 		return( NULL );
 	}
 
-	vips_dbuf_writef( &dbuf, "  </properties>\n" );  
-	vips_dbuf_writef( &dbuf, "</image>\n" );  
+	vips_streamo_writef( streamo, "  </properties>\n" );  
+	vips_streamo_writef( streamo, "</image>\n" );  
 
-	return( (char *) vips_dbuf_steal( &dbuf, NULL ) ); 
+	return( vips_streamo_steal_text( streamo ) ); 
 }
 
 /* Append XML to output fd.