--- /dev/null
+// Copyright (C) 2003 Adam Megacz <adam@ibex.org> all rights reserved.
+//
+// You may modify, copy, and redistribute this code under the terms of
+// the GNU Library Public License version 2.1, with the exception of
+// the portion of clause 6a after the semicolon (aka the "obnoxious
+// relink clause")
+
+package org.ibex.util;
+
+/** packs 8-bit bytes into a String of 7-bit chars (to avoid the UTF-8 non-ASCII penalty) */
+public class PackBytesIntoString {
+
+ public static String pack(byte[] b, int off, int len) throws IllegalArgumentException {
+ if (len % 7 != 0) throw new IllegalArgumentException("len must be a multiple of 7");
+ StringBuffer ret = new StringBuffer();
+ for(int i=off; i<off+len; i += 7) {
+ long l = 0;
+ for(int j=6; j>=0; j--) {
+ l <<= 8;
+ l |= (b[i + j] & 0xff);
+ }
+ for(int j=0; j<8; j++) {
+ ret.append((char)(l & 0x7f));
+ l >>= 7;
+ }
+ }
+ return ret.toString();
+ }
+
+ public static byte[] unpack(String s) throws IllegalArgumentException {
+ if (s.length() % 8 != 0) throw new IllegalArgumentException("string length must be a multiple of 8");
+ byte[] ret = new byte[(s.length() / 8) * 7];
+ for(int i=0; i<s.length(); i += 8) {
+ long l = 0;
+ for(int j=7; j>=0; j--) {
+ l <<= 7;
+ l |= (s.charAt(i + j) & 0x7fL);
+ }
+ for(int j=0; j<7; j++) {
+ ret[(i / 8) * 7 + j] = (byte)(l & 0xff);
+ l >>= 8;
+ }
+ }
+ return ret;
+ }
+}
+