diff options
Diffstat (limited to 'doc/example-smob/image-type.c')
-rw-r--r-- | doc/example-smob/image-type.c | 47 |
1 files changed, 29 insertions, 18 deletions
diff --git a/doc/example-smob/image-type.c b/doc/example-smob/image-type.c index 1a03c9ce2..1cd0f8bca 100644 --- a/doc/example-smob/image-type.c +++ b/doc/example-smob/image-type.c @@ -1,6 +1,6 @@ /* image-type.c * - * Copyright (C) 1998, 2000 Free Software Foundation, Inc. + * Copyright (C) 1998, 2000, 2004 Free Software Foundation, Inc. * * 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 @@ -39,42 +39,53 @@ struct image { static SCM make_image (SCM name, SCM s_width, SCM s_height) { + SCM smob; struct image *image; - int width, height; - - SCM_ASSERT (SCM_STRINGP (name), name, SCM_ARG1, "make-image"); - SCM_ASSERT (SCM_INUMP (s_width), s_width, SCM_ARG2, "make-image"); - SCM_ASSERT (SCM_INUMP (s_height), s_height, SCM_ARG3, "make-image"); + int width = scm_to_int (s_width); + int height = scm_to_int (s_height); - width = SCM_INUM (s_width); - height = SCM_INUM (s_height); - + /* Step 1: Allocate the memory block. + */ image = (struct image *) scm_gc_malloc (sizeof (struct image), "image"); + + /* Step 2: Initialize it with straight code. + */ image->width = width; image->height = height; - image->pixels = scm_gc_malloc (width * height, "image pixels"); - image->name = name; + image->pixels = NULL; + image->name = SCM_BOOL_F; image->update_func = SCM_BOOL_F; - SCM_RETURN_NEWSMOB (image_tag, image); + /* Step 3: Create the smob. + */ + SCM_NEWSMOB (smob, image_tag, image); + + /* Step 4: Finish the initialization. + */ + image->name = name; + image->pixels = scm_gc_malloc (width * height, "image pixels"); + + return smob; } -static SCM +SCM clear_image (SCM image_smob) { int area; struct image *image; - SCM_ASSERT (SCM_SMOB_PREDICATE (image_tag, image_smob), - image_smob, SCM_ARG1, "clear-image"); + scm_assert_smob_type (image_tag, image_smob); image = (struct image *) SCM_SMOB_DATA (image_smob); area = image->width * image->height; memset (image->pixels, 0, area); - /* Invoke the image's update function. */ - if (image->update_func != SCM_BOOL_F) - scm_apply (image->update_func, SCM_EOL, SCM_EOL); + /* Invoke the image's update function. + */ + if (scm_is_true (image->update_func)) + scm_call_0 (image->update_func); + + scm_remember_upto_here_1 (image_smob); return SCM_UNSPECIFIED; } |