[pixbuf] Add generic concept of a pixel buffer

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/pixbuf.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2013 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * Pixel buffer
+ *
+ */
+
+#include <stdlib.h>
+#include <ipxe/umalloc.h>
+#include <ipxe/pixbuf.h>
+
+/**
+ * Free pixel buffer
+ *
+ * @v refcnt		Reference count
+ */
+static void free_pixbuf ( struct refcnt *refcnt ) {
+	struct pixel_buffer *pixbuf =
+		container_of ( refcnt, struct pixel_buffer, refcnt );
+
+	ufree ( pixbuf->data );
+	free ( pixbuf );
+}
+
+/**
+ * Allocate pixel buffer
+ *
+ * @v width		Width
+ * @h height		Height
+ * @ret pixbuf		Pixel buffer, or NULL on failure
+ */
+struct pixel_buffer * alloc_pixbuf ( unsigned int width, unsigned int height ) {
+	struct pixel_buffer *pixbuf;
+
+	/* Allocate and initialise structure */
+	pixbuf = zalloc ( sizeof ( *pixbuf ) );
+	if ( ! pixbuf )
+		goto err_alloc_pixbuf;
+	ref_init ( &pixbuf->refcnt, free_pixbuf );
+	pixbuf->width = width;
+	pixbuf->height = height;
+	pixbuf->len = ( width * height * sizeof ( uint32_t ) );
+
+	/* Allocate pixel data buffer */
+	pixbuf->data = umalloc ( pixbuf->len );
+	if ( ! pixbuf->data )
+		goto err_alloc_data;
+
+	return pixbuf;
+
+ err_alloc_data:
+	pixbuf_put ( pixbuf );
+ err_alloc_pixbuf:
+	return NULL;
+}

src/include/ipxe/pixbuf.h

@@ -0,0 +1,55 @@
+#ifndef _IPXE_PIXBUF_H
+#define _IPXE_PIXBUF_H
+
+/** @file
+ *
+ * Pixel buffer
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stddef.h>
+#include <ipxe/refcnt.h>
+#include <ipxe/uaccess.h>
+
+/** A pixel buffer */
+struct pixel_buffer {
+	/** Reference count */
+	struct refcnt refcnt;
+	/** Width */
+	unsigned int width;
+	/** Height */
+	unsigned int height;
+	/** 32-bit (8:8:8:8) xRGB pixel data, in host-endian order */
+	userptr_t data;
+	/** Total length */
+	size_t len;
+};
+
+/**
+ * Get reference to pixel buffer
+ *
+ * @v pixbuf		Pixel buffer
+ * @ret pixbuf		Pixel buffer
+ */
+static inline __attribute__ (( always_inline )) struct pixel_buffer *
+pixbuf_get ( struct pixel_buffer *pixbuf ) {
+	ref_get ( &pixbuf->refcnt );
+	return pixbuf;
+}
+
+/**
+ * Drop reference to pixel buffer
+ *
+ * @v pixbuf		Pixel buffer
+ */
+static inline __attribute__ (( always_inline )) void
+pixbuf_put ( struct pixel_buffer *pixbuf ) {
+	ref_put ( &pixbuf->refcnt );
+}
+
+extern struct pixel_buffer * alloc_pixbuf ( unsigned int width,
+					    unsigned int height );
+
+#endif /* _IPXE_PIXBUF_H */