feature: JPK encryption and databased events

common/decryption/jpk.go

@@ -0,0 +1,117 @@
+package decryption
+
+/*
+	This code is HEAVILY based from
+	https://github.com/Chakratos/ReFrontier/blob/master/ReFrontier/Unpack.cs
+*/
+
+import (
+	"erupe-ce/common/byteframe"
+	"io"
+)
+
+var m_shiftIndex int = 0
+var m_flag byte = byte(0)
+
+func UnpackSimple(data []byte) []byte {
+	m_shiftIndex = 0
+	m_flag = byte(0)
+
+	bf := byteframe.NewByteFrameFromBytes(data)
+	bf.SetLE()
+	header := bf.ReadUint32()
+
+	println("Decrypting")
+
+	if header == 0x1A524B4A {
+		bf.Seek(0x2, io.SeekCurrent)
+		jpkType := bf.ReadUint16()
+		println("JPK Type: ", jpkType)
+
+		switch jpkType {
+		case 3:
+			startOffset := bf.ReadInt32()
+			outSize := bf.ReadInt32()
+			outBuffer := make([]byte, outSize)
+			bf.Seek(int64(startOffset), io.SeekStart)
+			ProcessDecode(bf, outBuffer)
+
+			return outBuffer
+		}
+	}
+
+	println("Skipping")
+
+	return data
+}
+
+func ProcessDecode(data *byteframe.ByteFrame, outBuffer []byte) {
+	outIndex := 0
+
+	for int(data.Index()) < len(data.Data()) && outIndex < len(outBuffer)-1 {
+		if JPKBitshift(data) == 0 {
+			outBuffer[outIndex] = ReadByte(data)
+			outIndex++
+			continue
+		} else {
+			if JPKBitshift(data) == 0 {
+				len := (JPKBitshift(data) << 1) | JPKBitshift(data)
+				off := ReadByte(data)
+				JPKCopy(outBuffer, int(off), int(len)+3, &outIndex)
+				continue
+			} else {
+				hi := ReadByte(data)
+				lo := ReadByte(data)
+				var len int = int((hi & 0xE0)) >> 5
+				var off int = ((int(hi) & 0x1F) << 8) | int(lo)
+				if len != 0 {
+					JPKCopy(outBuffer, off, len+2, &outIndex)
+					continue
+				} else {
+					if JPKBitshift(data) == 0 {
+						len := (JPKBitshift(data) << 3) | (JPKBitshift(data) << 2) | (JPKBitshift(data) << 1) | JPKBitshift(data)
+						JPKCopy(outBuffer, off, int(len)+2+8, &outIndex)
+						continue
+					} else {
+						temp := ReadByte(data)
+						if temp == 0xFF {
+							for i := 0; i < off+0x1B; i++ {
+								outBuffer[outIndex] = ReadByte(data)
+								outIndex++
+								continue
+							}
+						} else {
+							JPKCopy(outBuffer, off, int(temp)+0x1a, &outIndex)
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
+func JPKBitshift(data *byteframe.ByteFrame) byte {
+	m_shiftIndex--
+
+	if m_shiftIndex < 0 {
+		m_shiftIndex = 7
+		m_flag = ReadByte(data)
+	}
+
+	return (byte)((m_flag >> m_shiftIndex) & 1)
+}
+
+func JPKCopy(outBuffer []byte, offset int, length int, index *int) {
+	for i := 0; i < length; i++ {
+		outBuffer[*index] = outBuffer[*index-offset-1]
+		*index++
+	}
+}
+
+func ReadByte(bf *byteframe.ByteFrame) byte {
+	value := bf.ReadUint8()
+	if value < 0 {
+		println("Not implemented")
+	}
+	return byte(value)
+}