From 9d052c650ba59ddc8132bce881bd487df31c5348 Mon Sep 17 00:00:00 2001 From: Masaya Tojo Date: Sat, 10 Aug 2024 23:08:10 +0900 Subject: Add `image-format` prefix to library name --- image-format/pnm/private/double-byte.scm | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 image-format/pnm/private/double-byte.scm (limited to 'image-format/pnm/private/double-byte.scm') diff --git a/image-format/pnm/private/double-byte.scm b/image-format/pnm/private/double-byte.scm new file mode 100644 index 0000000..156b409 --- /dev/null +++ b/image-format/pnm/private/double-byte.scm @@ -0,0 +1,29 @@ +;;; R7RS-PNM --- Library for reading and writing PNM (Portable Any Map) files for R7RS +;;; Copyright © 2024 Masaya Tojo +;;; +;;; This file is part of R7RS-PNM. +;;; +;;; R7RS-PNM is free software: you can redistribute it and/or modify it +;;; under the terms of the GNU Lesser General Public License as published +;;; by the Free Software Foundation, either version 3 of the License, or +;;; (at your option) any later version. +;;; +;;; R7RS-PNM 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 Lesser General Public License for more details. +;;; +;;; You should have received a copy of the GNU Lesser General Public License +;;; along with R7RS-PNM. If not, see . + +(define-library (image-format pnm private double-byte) + (export split-double-byte combine-bytes) + (import (scheme base) + (image-format pnm private bitwise)) + (begin + (define (split-double-byte v) + (values (arithmetic-shift v -8) + (bitwise-and v 255))) + + (define (combine-bytes l r) + (bitwise-ior (arithmetic-shift l 8) r)))) -- cgit v1.2.3