diff options
author | Rafael Marçalo <public@rafaelmarcalo.xyz> | 2024-09-05 16:31:33 +0100 |
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committer | Rafael Marçalo <public@rafaelmarcalo.xyz> | 2024-09-05 16:31:33 +0100 |
commit | 8b67572ad7e1508341345dc46a2597e9fa170cbb (patch) | |
tree | 8f37c4d60ce0f07b9eaf30be34f39298da97b242 /src/com/pkrandom/newnds/CRC16.java | |
parent | b65f4a80da28e7ec4de16c8b1abf906e8d7be2c5 (diff) |
Diffstat (limited to 'src/com/pkrandom/newnds/CRC16.java')
-rwxr-xr-x | src/com/pkrandom/newnds/CRC16.java | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/com/pkrandom/newnds/CRC16.java b/src/com/pkrandom/newnds/CRC16.java new file mode 100755 index 0000000..8ae8ad2 --- /dev/null +++ b/src/com/pkrandom/newnds/CRC16.java @@ -0,0 +1,52 @@ +package com.pkrandom.newnds; + +/*----------------------------------------------------------------------------*/ +/*-- CRC16.java - crc16 calculator for NDS checksums --*/ +/*-- Code derived from "Nintendo DS rom tool", copyright (C) DevkitPro --*/ +/*-- Original Code by Rafael Vuijk, Dave Murphy, Alexei Karpenko --*/ +/*-- --*/ +/*-- --*/ +/*-- 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 3 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, see <http://www.gnu.org/licenses/>. --*/ +/*----------------------------------------------------------------------------*/ + +public class CRC16 { + private static final int[] table = { 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241, 0xC601, + 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440, 0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, + 0xCE81, 0x0E40, 0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841, 0xD801, 0x18C0, 0x1980, + 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40, 0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41, + 0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641, 0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, + 0xD1C1, 0xD081, 0x1040, 0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240, 0x3600, 0xF6C1, + 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441, 0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, + 0xFE41, 0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840, 0x2800, 0xE8C1, 0xE981, 0x2940, + 0xEB01, 0x2BC0, 0x2A80, 0xEA41, 0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40, 0xE401, + 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640, 0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, + 0x2080, 0xE041, 0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240, 0x6600, 0xA6C1, 0xA781, + 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441, 0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41, + 0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840, 0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, + 0x7BC0, 0x7A80, 0xBA41, 0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40, 0xB401, 0x74C0, + 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640, 0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, + 0xB041, 0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241, 0x9601, 0x56C0, 0x5780, 0x9741, + 0x5500, 0x95C1, 0x9481, 0x5440, 0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40, 0x5A00, + 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841, 0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, + 0x8A81, 0x4A40, 0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41, 0x4400, 0x84C1, 0x8581, + 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641, 0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040 }; + + public static short calculate(byte[] data, int offset, int length) { + int crc = 0xFFFF; + for (int i = 0; i < length; i++) { + crc = ((crc >>> 8) ^ table[(crc ^ data[i + offset]) & 0xff]); + } + return (short) crc; + } +}
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