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+;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*-
+;;;; *************************************************************************
+;;;; FILE IDENTIFICATION
+;;;;
+;;;; Name:          compress.cl
+;;;; Purpose:       UFFI Example file for zlib compression
+;;;; Programmer:    Kevin M. Rosenberg
+;;;; Date Started:  Feb 2002
+;;;;
+;;;; $Id: compress.lisp,v 1.1 2002/09/30 10:02:36 kevin Exp $
+;;;;
+;;;; This file, part of UFFI, is Copyright (c) 2002 by Kevin M. Rosenberg
+;;;;
+;;;; UFFI users are granted the rights to distribute and use this software
+;;;; as governed by the terms of the Lisp Lesser GNU Public License
+;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
+;;;; *************************************************************************
+
+(in-package :cl-user)
+
+(unless (uffi:load-foreign-library
+	 (uffi:find-foreign-library
+	  "libz"
+	  '("/usr/local/lib/" "/usr/lib/" "/zlib/")
+	  :types '("so" "a" "dylib"))
+	 :module "zlib" 
+	 :supporting-libraries '("c"))
+  (warn "Unable to load zlib"))
+
+(uffi:def-function ("compress" c-compress)
+    ((dest (* :unsigned-char))
+     (destlen (* :long))
+     (source :cstring)
+     (source-len :long))
+  :returning :int
+  :module "zlib")
+  
+(defun compress (source)
+  "Returns two values: array of bytes containing the compressed data
+ and the numbe of compressed bytes"
+  (let* ((sourcelen (length source))
+	 (destsize (+ 12 (ceiling (* sourcelen 1.01))))
+	 (dest (uffi:allocate-foreign-string destsize :unsigned t))
+	 (destlen (uffi:allocate-foreign-object :long)))
+    (setf (uffi:deref-pointer destlen :long) destsize)
+    (uffi:with-cstring (source-native source)
+      (let ((result (c-compress dest destlen source-native sourcelen))
+	    (newdestlen (uffi:deref-pointer destlen :long)))
+	(unwind-protect
+	    (if (zerop result)
+		(values (uffi:convert-from-foreign-string 
+			 dest
+			 :length newdestlen
+			 :null-terminated-p nil)
+			newdestlen)
+	      (error "zlib error, code ~D" result))
+	  (progn
+	    (uffi:free-foreign-object destlen)
+	    (uffi:free-foreign-object dest)))))))
+
+
+#+examples-uffi
+(progn
+  (flet ((print-results (str)
+	   (multiple-value-bind (compressed len) (compress str)
+	       (format t "~&(compress ~S) => " str)
+	       (dotimes (i len)
+		 (format t "~X" (char-code (char compressed i))))
+	       (format t ",~D" len))))
+    (print-results "")
+    (print-results "test")
+    (print-results "test2")))
+
+;; Results of the above on my system:
+;; (compress "") => 789c300001,8
+;; (compress "test") => 789c2b492d2e1045d1c1,12
+;; (compress "test2") => 789c2b492d2e31206501f3,13