mirror of
https://github.com/AppleCommander/AppleCommander.git
synced 2024-09-27 18:57:56 +00:00
171 lines
4.8 KiB
Java
171 lines
4.8 KiB
Java
|
/*
|
||
|
* AppleCommander - An Apple ][ image utility.
|
||
|
* Copyright (C) 2002 by Robert Greene
|
||
|
* robgreene at users.sourceforge.net
|
||
|
*
|
||
|
* 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 (at your
|
||
|
* option) 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.,
|
||
|
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||
|
*/
|
||
|
package com.webcodepro.applecommander.storage;
|
||
|
|
||
|
import java.util.Date;
|
||
|
import java.util.GregorianCalendar;
|
||
|
|
||
|
/**
|
||
|
* This class contains helper methods for dealing with Apple2 data.
|
||
|
* <p>
|
||
|
* Date created: Oct 5, 2002 4:16:16 PM
|
||
|
* @author: Rob Greene
|
||
|
*/
|
||
|
public class AppleUtil {
|
||
|
|
||
|
/**
|
||
|
* Compute the value of a word.
|
||
|
* Pulls value from buffer given the offset.
|
||
|
* A word is two bytes, in standard Apple LO/HI format.
|
||
|
*/
|
||
|
public static int getWordValue(byte[] buffer, int offset) {
|
||
|
return getWordValue(buffer[offset], buffer[offset+1]);
|
||
|
}
|
||
|
/**
|
||
|
* Compute the value of a word.
|
||
|
*/
|
||
|
public static int getWordValue(byte low, byte high) {
|
||
|
return getUnsignedByte(low) + getUnsignedByte(high)*256;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Compute the value of a 3 byte value. This may be ProDOS specific.
|
||
|
* Pulls value from buffer given the offset.
|
||
|
* Stored in standard Apple LO/HI format.
|
||
|
*/
|
||
|
public static int get3ByteValue(byte[] buffer, int offset) {
|
||
|
return getUnsignedByte(buffer[offset])
|
||
|
+ getUnsignedByte(buffer[offset+1])*256
|
||
|
+ getUnsignedByte(buffer[offset+2])*65536;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Extract out an unsigned byte as an int.
|
||
|
* All Java bytes are signed; need to convert to an int
|
||
|
* and remove the sign.
|
||
|
*/
|
||
|
public static int getUnsignedByte(byte value) {
|
||
|
return (int) value & 0xff;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Count the number of bits set in a byte.
|
||
|
*/
|
||
|
public static int getBitCount(byte byt) {
|
||
|
int count = 0;
|
||
|
for (int ix=0; ix<8; ix++) {
|
||
|
if (isBitSet(byt, ix)) count++;
|
||
|
}
|
||
|
return count;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Determine if a specific bit is set.
|
||
|
*/
|
||
|
public static boolean isBitSet(byte byt, int bit) {
|
||
|
byte[] masks = { (byte)0x01, (byte)0x02,(byte)0x04, (byte)0x08,
|
||
|
(byte)0x10, (byte)0x20, (byte)0x40, (byte)0x80 };
|
||
|
return (byt & masks[bit]) != 0;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Extract a string from the buffer.
|
||
|
*/
|
||
|
public static String getString(byte[] buffer, int offset, int length) {
|
||
|
byte[] value = new byte[length];
|
||
|
for (int i=0; i<length; i++) {
|
||
|
byte ch = buffer[offset+i];
|
||
|
ch &= 0x7f;
|
||
|
value[i] = ch;
|
||
|
}
|
||
|
return new String(value);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Extract a Pascal string from the buffer.
|
||
|
*/
|
||
|
public static String getPascalString(byte[] buffer, int offset) {
|
||
|
int length = getUnsignedByte(buffer[offset]);
|
||
|
return getString(buffer, offset+1, length);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Extract a Pascal date from the buffer.
|
||
|
*/
|
||
|
public static Date getPascalDate(byte[] buffer, int offset) {
|
||
|
int pascalDate = getWordValue(buffer, offset);
|
||
|
int month = pascalDate & 0x000f;
|
||
|
int day = (pascalDate & 0x00f0) >> 4;
|
||
|
int year = (pascalDate & 0xff00) >> 8;
|
||
|
if (year < 50) year+= 2000;
|
||
|
if (year < 100) year+= 1900;
|
||
|
GregorianCalendar gc = new GregorianCalendar(year, month, day);
|
||
|
return gc.getTime();
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Extract a ProDOS string from the buffer.
|
||
|
*/
|
||
|
public static String getProdosString(byte[] buffer, int offset) {
|
||
|
int length = getUnsignedByte(buffer[offset]) & 0x0f;
|
||
|
return getString(buffer, offset+1, length);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Format a byte value as hexidecimal.
|
||
|
*/
|
||
|
public static String getFormattedByte(int byt) {
|
||
|
String[] values = { "0", "1", "2", "3", "4", "5", "6", "7",
|
||
|
"8", "9", "A", "B", "C", "D", "E", "F" };
|
||
|
int byt1 = byt & 0x0f;
|
||
|
int byt2 = (byt & 0xf0) >> 4;
|
||
|
return values[byt2] + values[byt1];
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Format a word value as hexidecimal.
|
||
|
*/
|
||
|
public static String getFormattedWord(int word) {
|
||
|
return getFormattedByte((word & 0xff00) >> 8)
|
||
|
+ getFormattedByte(word & 0x00ff);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Extract a ProDOS date from the buffer.
|
||
|
*/
|
||
|
public static Date getProdosDate(byte[] buffer, int offset) {
|
||
|
int ymd = getWordValue(buffer, offset);
|
||
|
if (ymd == 0) return null;
|
||
|
int hm = getWordValue(buffer, offset+2);
|
||
|
|
||
|
int day = ymd & 0x001f; // bits 0-4
|
||
|
int month = (ymd & 0x01e0) >> 5; // bits 5-8
|
||
|
int year = (ymd & 0xfe00) >> 9; // bits 9-15
|
||
|
int minute = hm & 0x003f; // bits 0-5
|
||
|
int hour = (hm & 0x1f00) >> 8; // bits 8-12
|
||
|
|
||
|
if (year < 50) year+= 2000;
|
||
|
if (year < 100) year+= 1900;
|
||
|
|
||
|
GregorianCalendar gc = new GregorianCalendar(year, month, day, hour, minute);
|
||
|
return gc.getTime();
|
||
|
}
|
||
|
}
|