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epubreader/public/bitjs/archive/rarvm.js

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Initial commit from existing app
2020-04-21 20:37:42 +00:00
/**
* rarvm.js
*
* Licensed under the MIT License
*
* Copyright(c) 2017 Google Inc.
*/
/**
* CRC Implementation.
*/
const CRCTab = new Array(256).fill(0);
// Helper functions between signed and unsigned integers.
/**
* -1 becomes 0xffffffff
*/
function fromSigned32ToUnsigned32(val) {
return (val < 0) ? (val += 0x100000000) : val;
}
/**
* 0xffffffff becomes -1
*/
function fromUnsigned32ToSigned32(val) {
return (val >= 0x80000000) ? (val -= 0x100000000) : val;
}
/**
* -1 becomes 0xff
*/
function fromSigned8ToUnsigned8(val) {
return (val < 0) ? (val += 0x100) : val;
}
/**
* 0xff becomes -1
*/
function fromUnsigned8ToSigned8(val) {
return (val >= 0x80) ? (val -= 0x100) : val;
}
function InitCRC() {
for (let i = 0; i < 256; ++i) {
let c = i;
for (let j = 0; j < 8; ++j) {
// Read http://stackoverflow.com/questions/6798111/bitwise-operations-on-32-bit-unsigned-ints
// for the bitwise operator issue (JS interprets operands as 32-bit signed
// integers and we need to deal with unsigned ones here).
c = ((c & 1) ? ((c >>> 1) ^ 0xEDB88320) : (c >>> 1)) >>> 0;
}
CRCTab[i] = c;
}
}
/**
* @param {number} startCRC
* @param {Uint8Array} arr
* @return {number}
*/
function CRC(startCRC, arr) {
if (CRCTab[1] == 0) {
InitCRC();
}
/*
#if defined(LITTLE_ENDIAN) && defined(PRESENT_INT32) && defined(ALLOW_NOT_ALIGNED_INT)
while (Size>0 && ((long)Data & 7))
{
StartCRC=CRCTab[(byte)(StartCRC^Data[0])]^(StartCRC>>8);
Size--;
Data++;
}
while (Size>=8)
{
StartCRC^=*(uint32 *)Data;
StartCRC=CRCTab[(byte)StartCRC]^(StartCRC>>8);
StartCRC=CRCTab[(byte)StartCRC]^(StartCRC>>8);
StartCRC=CRCTab[(byte)StartCRC]^(StartCRC>>8);
StartCRC=CRCTab[(byte)StartCRC]^(StartCRC>>8);
StartCRC^=*(uint32 *)(Data+4);
StartCRC=CRCTab[(byte)StartCRC]^(StartCRC>>8);
StartCRC=CRCTab[(byte)StartCRC]^(StartCRC>>8);
StartCRC=CRCTab[(byte)StartCRC]^(StartCRC>>8);
StartCRC=CRCTab[(byte)StartCRC]^(StartCRC>>8);
Data+=8;
Size-=8;
}
#endif
*/
for (let i = 0; i < arr.length; ++i) {
const byte = ((startCRC ^ arr[i]) >>> 0) & 0xff;
startCRC = (CRCTab[byte] ^ (startCRC >>> 8)) >>> 0;
}
return startCRC;
}
// ============================================================================================== //
/**
* RarVM Implementation.
*/
const VM_MEMSIZE = 0x40000;
const VM_MEMMASK = (VM_MEMSIZE - 1);
const VM_GLOBALMEMADDR = 0x3C000;
const VM_GLOBALMEMSIZE = 0x2000;
const VM_FIXEDGLOBALSIZE = 64;
const MAXWINSIZE = 0x400000;
const MAXWINMASK = (MAXWINSIZE - 1);
/**
*/
const VM_Commands = {
VM_MOV: 0,
VM_CMP: 1,
VM_ADD: 2,
VM_SUB: 3,
VM_JZ: 4,
VM_JNZ: 5,
VM_INC: 6,
VM_DEC: 7,
VM_JMP: 8,
VM_XOR: 9,
VM_AND: 10,
VM_OR: 11,
VM_TEST: 12,
VM_JS: 13,
VM_JNS: 14,
VM_JB: 15,
VM_JBE: 16,
VM_JA: 17,
VM_JAE: 18,
VM_PUSH: 19,
VM_POP: 20,
VM_CALL: 21,
VM_RET: 22,
VM_NOT: 23,
VM_SHL: 24,
VM_SHR: 25,
VM_SAR: 26,
VM_NEG: 27,
VM_PUSHA: 28,
VM_POPA: 29,
VM_PUSHF: 30,
VM_POPF: 31,
VM_MOVZX: 32,
VM_MOVSX: 33,
VM_XCHG: 34,
VM_MUL: 35,
VM_DIV: 36,
VM_ADC: 37,
VM_SBB: 38,
VM_PRINT: 39,
/*
#ifdef VM_OPTIMIZE
VM_MOVB, VM_MOVD, VM_CMPB, VM_CMPD,
VM_ADDB, VM_ADDD, VM_SUBB, VM_SUBD, VM_INCB, VM_INCD, VM_DECB, VM_DECD,
VM_NEGB, VM_NEGD,
#endif
*/
// TODO: This enum value would be much larger if VM_OPTIMIZE.
VM_STANDARD: 40,
};
/**
*/
const VM_StandardFilters = {
VMSF_NONE: 0,
VMSF_E8: 1,
VMSF_E8E9: 2,
VMSF_ITANIUM: 3,
VMSF_RGB: 4,
VMSF_AUDIO: 5,
VMSF_DELTA: 6,
VMSF_UPCASE: 7,
};
/**
*/
const VM_Flags = {
VM_FC: 1,
VM_FZ: 2,
VM_FS: 0x80000000,
};
/**
*/
const VM_OpType = {
VM_OPREG: 0,
VM_OPINT: 1,
VM_OPREGMEM: 2,
VM_OPNONE: 3,
};
/**
* Finds the key that maps to a given value in an object. This function is useful in debugging
* variables that use the above enums.
* @param {Object} obj
* @param {number} val
* @return {string} The key/enum value as a string.
*/
function findKeyForValue(obj, val) {
for (let key in obj) {
if (obj[key] === val) {
return key;
}
}
return null;
}
function getDebugString(obj, val) {
let s = 'Unknown.';
if (obj === VM_Commands) {
s = 'VM_Commands.';
} else if (obj === VM_StandardFilters) {
s = 'VM_StandardFilters.';
} else if (obj === VM_Flags) {
s = 'VM_OpType.';
} else if (obj === VM_OpType) {
s = 'VM_OpType.';
}
return s + findKeyForValue(obj, val);
}
/**
*/
class VM_PreparedOperand {
constructor() {
/** @type {VM_OpType} */
this.Type;
/** @type {number} */
this.Data = 0;
/** @type {number} */
this.Base = 0;
// TODO: In C++ this is a uint*
/** @type {Array<number>} */
this.Addr = null;
};
/** @return {string} */
toString() {
if (this.Type === null) {
return 'Error: Type was null in VM_PreparedOperand';
}
return '{ '
+ 'Type: ' + getDebugString(VM_OpType, this.Type)
+ ', Data: ' + this.Data
+ ', Base: ' + this.Base
+ ' }';
}
}
/**
*/
class VM_PreparedCommand {
constructor() {
/** @type {VM_Commands} */
this.OpCode;
/** @type {boolean} */
this.ByteMode = false;
/** @type {VM_PreparedOperand} */
this.Op1 = new VM_PreparedOperand();
/** @type {VM_PreparedOperand} */
this.Op2 = new VM_PreparedOperand();
}
/** @return {string} */
toString(indent) {
if (this.OpCode === null) {
return 'Error: OpCode was null in VM_PreparedCommand';
}
indent = indent || '';
return indent + '{\n'
+ indent + ' OpCode: ' + getDebugString(VM_Commands, this.OpCode) + ',\n'
+ indent + ' ByteMode: ' + this.ByteMode + ',\n'
+ indent + ' Op1: ' + this.Op1.toString() + ',\n'
+ indent + ' Op2: ' + this.Op2.toString() + ',\n'
+ indent + '}';
}
}
/**
*/
class VM_PreparedProgram {
constructor() {
/** @type {Array<VM_PreparedCommand>} */
this.Cmd = [];
/** @type {Array<VM_PreparedCommand>} */
this.AltCmd = null;
/** @type {Uint8Array} */
this.GlobalData = new Uint8Array();
/** @type {Uint8Array} */
this.StaticData = new Uint8Array(); // static data contained in DB operators
/** @type {Uint32Array} */
this.InitR = new Uint32Array(7);
/**
* A pointer to bytes that have been filtered by a program.
* @type {Uint8Array}
*/
this.FilteredData = null;
}
/** @return {string} */
toString() {
let s = '{\n Cmd: [\n';
for (let i = 0; i < this.Cmd.length; ++i) {
s += this.Cmd[i].toString(' ') + ',\n';
}
s += '],\n';
// TODO: Dump GlobalData, StaticData, InitR?
s += ' }\n';
return s;
}
}
/**
*/
class UnpackFilter {
constructor() {
/** @type {number} */
this.BlockStart = 0;
/** @type {number} */
this.BlockLength = 0;
/** @type {number} */
this.ExecCount = 0;
/** @type {boolean} */
this.NextWindow = false;
// position of parent filter in Filters array used as prototype for filter
// in PrgStack array. Not defined for filters in Filters array.
/** @type {number} */
this.ParentFilter = null;
/** @type {VM_PreparedProgram} */
this.Prg = new VM_PreparedProgram();
}
}
const VMCF_OP0 = 0;
const VMCF_OP1 = 1;
const VMCF_OP2 = 2;
const VMCF_OPMASK = 3;
const VMCF_BYTEMODE = 4;
const VMCF_JUMP = 8;
const VMCF_PROC = 16;
const VMCF_USEFLAGS = 32;
const VMCF_CHFLAGS = 64;
const VM_CmdFlags = [
/* VM_MOV */ VMCF_OP2 | VMCF_BYTEMODE ,
/* VM_CMP */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_ADD */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_SUB */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_JZ */ VMCF_OP1 | VMCF_JUMP | VMCF_USEFLAGS ,
/* VM_JNZ */ VMCF_OP1 | VMCF_JUMP | VMCF_USEFLAGS ,
/* VM_INC */ VMCF_OP1 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_DEC */ VMCF_OP1 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_JMP */ VMCF_OP1 | VMCF_JUMP ,
/* VM_XOR */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_AND */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_OR */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_TEST */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_JS */ VMCF_OP1 | VMCF_JUMP | VMCF_USEFLAGS ,
/* VM_JNS */ VMCF_OP1 | VMCF_JUMP | VMCF_USEFLAGS ,
/* VM_JB */ VMCF_OP1 | VMCF_JUMP | VMCF_USEFLAGS ,
/* VM_JBE */ VMCF_OP1 | VMCF_JUMP | VMCF_USEFLAGS ,
/* VM_JA */ VMCF_OP1 | VMCF_JUMP | VMCF_USEFLAGS ,
/* VM_JAE */ VMCF_OP1 | VMCF_JUMP | VMCF_USEFLAGS ,
/* VM_PUSH */ VMCF_OP1 ,
/* VM_POP */ VMCF_OP1 ,
/* VM_CALL */ VMCF_OP1 | VMCF_PROC ,
/* VM_RET */ VMCF_OP0 | VMCF_PROC ,
/* VM_NOT */ VMCF_OP1 | VMCF_BYTEMODE ,
/* VM_SHL */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_SHR */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_SAR */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_NEG */ VMCF_OP1 | VMCF_BYTEMODE | VMCF_CHFLAGS ,
/* VM_PUSHA */ VMCF_OP0 ,
/* VM_POPA */ VMCF_OP0 ,
/* VM_PUSHF */ VMCF_OP0 | VMCF_USEFLAGS ,
/* VM_POPF */ VMCF_OP0 | VMCF_CHFLAGS ,
/* VM_MOVZX */ VMCF_OP2 ,
/* VM_MOVSX */ VMCF_OP2 ,
/* VM_XCHG */ VMCF_OP2 | VMCF_BYTEMODE ,
/* VM_MUL */ VMCF_OP2 | VMCF_BYTEMODE ,
/* VM_DIV */ VMCF_OP2 | VMCF_BYTEMODE ,
/* VM_ADC */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_USEFLAGS | VMCF_CHFLAGS ,
/* VM_SBB */ VMCF_OP2 | VMCF_BYTEMODE | VMCF_USEFLAGS | VMCF_CHFLAGS ,
/* VM_PRINT */ VMCF_OP0 ,
];
/**
*/
class StandardFilterSignature {
/**
* @param {number} length
* @param {number} crc
* @param {VM_StandardFilters} type
*/
constructor(length, crc, type) {
/** @type {number} */
this.Length = length;
/** @type {number} */
this.CRC = crc;
/** @type {VM_StandardFilters} */
this.Type = type;
}
}
/**
* @type {Array<StandardFilterSignature>}
*/
const StdList = [
new StandardFilterSignature(53, 0xad576887, VM_StandardFilters.VMSF_E8),
new StandardFilterSignature(57, 0x3cd7e57e, VM_StandardFilters.VMSF_E8E9),
new StandardFilterSignature(120, 0x3769893f, VM_StandardFilters.VMSF_ITANIUM),
new StandardFilterSignature(29, 0x0e06077d, VM_StandardFilters.VMSF_DELTA),
new StandardFilterSignature(149, 0x1c2c5dc8, VM_StandardFilters.VMSF_RGB),
new StandardFilterSignature(216, 0xbc85e701, VM_StandardFilters.VMSF_AUDIO),
new StandardFilterSignature(40, 0x46b9c560, VM_StandardFilters.VMSF_UPCASE),
];
/**
* @constructor
*/
class RarVM {
constructor() {
/** @private {Uint8Array} */
this.mem_ = null;
/** @private {Uint32Array<number>} */
this.R_ = new Uint32Array(8);
/** @private {number} */
this.flags_ = 0;
}
/**
* Initializes the memory of the VM.
*/
init() {
if (!this.mem_) {
this.mem_ = new Uint8Array(VM_MEMSIZE);
}
}
/**
* @param {Uint8Array} code
* @return {VM_StandardFilters}
*/
isStandardFilter(code) {
const codeCRC = (CRC(0xffffffff, code, code.length) ^ 0xffffffff) >>> 0;
for (let i = 0; i < StdList.length; ++i) {
if (StdList[i].CRC == codeCRC && StdList[i].Length == code.length)
return StdList[i].Type;
}
return VM_StandardFilters.VMSF_NONE;
}
/**
* @param {VM_PreparedOperand} op
* @param {boolean} byteMode
* @param {bitjs.io.BitStream} bstream A rtl bit stream.
*/
decodeArg(op, byteMode, bstream) {
const data = bstream.peekBits(16);
if (data & 0x8000) {
op.Type = VM_OpType.VM_OPREG; // Operand is register (R[0]..R[7])
bstream.readBits(1); // 1 flag bit and...
op.Data = bstream.readBits(3); // ... 3 register number bits
op.Addr = [this.R_[op.Data]] // TODO &R[Op.Data] // Register address
} else {
if ((data & 0xc000) == 0) {
op.Type = VM_OpType.VM_OPINT; // Operand is integer
bstream.readBits(2); // 2 flag bits
if (byteMode) {
op.Data = bstream.readBits(8); // Byte integer.
} else {
op.Data = RarVM.readData(bstream); // 32 bit integer.
}
} else {
// Operand is data addressed by register data, base address or both.
op.Type = VM_OpType.VM_OPREGMEM;
if ((data & 0x2000) == 0) {
bstream.readBits(3); // 3 flag bits
// Base address is zero, just use the address from register.
op.Data = bstream.readBits(3); // (Data>>10)&7
op.Addr = [this.R_[op.Data]]; // TODO &R[op.Data]
op.Base = 0;
} else {
bstream.readBits(4); // 4 flag bits
if ((data & 0x1000) == 0) {
// Use both register and base address.
op.Data = bstream.readBits(3);
op.Addr = [this.R_[op.Data]]; // TODO &R[op.Data]
} else {
// Use base address only. Access memory by fixed address.
op.Data = 0;
}
op.Base = RarVM.readData(bstream); // Read base address.
}
}
}
}
/**
* @param {VM_PreparedProgram} prg
*/
execute(prg) {
this.R_.set(prg.InitR);
const globalSize = Math.min(prg.GlobalData.length, VM_GLOBALMEMSIZE);
if (globalSize) {
this.mem_.set(prg.GlobalData.subarray(0, globalSize), VM_GLOBALMEMADDR);
}
const staticSize = Math.min(prg.StaticData.length, VM_GLOBALMEMSIZE - globalSize);
if (staticSize) {
this.mem_.set(prg.StaticData.subarray(0, staticSize), VM_GLOBALMEMADDR + globalSize);
}
this.R_[7] = VM_MEMSIZE;
this.flags_ = 0;
const preparedCodes = prg.AltCmd ? prg.AltCmd : prg.Cmd;
if (prg.Cmd.length > 0 && !this.executeCode(preparedCodes)) {
// Invalid VM program. Let's replace it with 'return' command.
preparedCode.OpCode = VM_Commands.VM_RET;
}
const dataView = new DataView(this.mem_.buffer, VM_GLOBALMEMADDR);
let newBlockPos = dataView.getUint32(0x20, true /* little endian */) & VM_MEMMASK;
const newBlockSize = dataView.getUint32(0x1c, true /* little endian */) & VM_MEMMASK;
if (newBlockPos + newBlockSize >= VM_MEMSIZE) {
newBlockPos = newBlockSize = 0;
}
prg.FilteredData = this.mem_.subarray(newBlockPos, newBlockPos + newBlockSize);
prg.GlobalData = new Uint8Array(0);
const dataSize = Math.min(dataView.getUint32(0x30), (VM_GLOBALMEMSIZE - VM_FIXEDGLOBALSIZE));
if (dataSize != 0) {
const len = dataSize + VM_FIXEDGLOBALSIZE;
prg.GlobalData = new Uint8Array(len);
prg.GlobalData.set(mem.subarray(VM_GLOBALMEMADDR, VM_GLOBALMEMADDR + len));
}
}
/**
* @param {Array<VM_PreparedCommand>} preparedCodes
* @return {boolean}
*/
executeCode(preparedCodes) {
let codeIndex = 0;
let cmd = preparedCodes[codeIndex];
// TODO: Why is this an infinite loop instead of just returning
// when a VM_RET is hit?
while (1) {
switch (cmd.OpCode) {
case VM_Commands.VM_RET:
if (this.R_[7] >= VM_MEMSIZE) {
return true;
}
//SET_IP(GET_VALUE(false,(uint *)&Mem[R[7] & VM_MEMMASK]));
this.R_[7] += 4;
continue;
case VM_Commands.VM_STANDARD:
this.executeStandardFilter(cmd.Op1.Data);
break;
default:
console.error('RarVM OpCode not supported: ' + getDebugString(VM_Commands, cmd.OpCode));
break;
} // switch (cmd.OpCode)
codeIndex++;
cmd = preparedCodes[codeIndex];
}
}
/**
* @param {number} filterType
*/
executeStandardFilter(filterType) {
switch (filterType) {
case VM_StandardFilters.VMSF_RGB: {
const dataSize = this.R_[4];
const width = this.R_[0] - 3;
const posR = this.R_[1];
const Channels = 3;
let srcOffset = 0;
let destOffset = dataSize;
// byte *SrcData=Mem,*DestData=SrcData+DataSize;
// SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
const dataView = new DataView(this.mem_.buffer, VM_GLOBALMEMADDR /* offset */);
dataView.setUint32(0x20 /* byte offset */,
dataSize /* value */,
true /* little endian */);
if (dataSize >= (VM_GLOBALMEMADDR / 2) || posR < 0) {
break;
}
for (let curChannel = 0; curChannel < Channels; ++curChannel) {
let prevByte=0;
for (let i = curChannel; i < dataSize; i += Channels) {
let predicted;
const upperPos = i - width;
if (upperPos >= 3) {
const upperByte = this.mem_[destOffset + upperPos];
const upperLeftByte = this.mem_[destOffset + upperPos - 3];
predicted = prevByte + upperByte - upperLeftByte;
const pa = Math.abs(predicted - prevByte);
const pb = Math.abs(predicted - upperByte);
const pc = Math.abs(predicted - upperLeftByte);
if (pa <= pb && pa <= pc) {
predicted = prevByte;
} else if (pb <= pc) {
predicted = upperByte;
} else {
predicted = upperLeftByte;
}
} else {
predicted = prevByte;
}
//DestData[I]=PrevByte=(byte)(Predicted-*(SrcData++));
prevByte = (predicted - this.mem_[srcOffset++]) & 0xff;
this.mem_[destOffset + i] = prevByte;
}
}
for (let i = posR, border = dataSize - 2; i < border; i += 3) {
const g = this.mem_[destOffset + i + 1];
this.mem_[destOffset + i] += g;
this.mem_[destOffset + i + 2] += g;
}
break;
}
// The C++ version of this standard filter uses an odd mixture of
// signed and unsigned integers, bytes and various casts. Careful!
case VM_StandardFilters.VMSF_AUDIO: {
const dataSize = this.R_[4];
const channels = this.R_[0];
let srcOffset = 0;
let destOffset = dataSize;
//SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
const dataView = new DataView(this.mem_.buffer, VM_GLOBALMEMADDR);
dataView.setUint32(0x20 /* byte offset */,
dataSize /* value */,
true /* little endian */);
if (dataSize >= VM_GLOBALMEMADDR / 2) {
break;
}
for (let curChannel = 0; curChannel < channels; ++curChannel) {
let prevByte = 0; // uint
let prevDelta = 0; // uint
let dif = [0, 0, 0, 0, 0, 0, 0];
let d1 = 0, d2 = 0, d3; // ints
let k1 = 0, k2 = 0, k3 = 0; // ints
for (var i = curChannel, byteCount = 0;
i < dataSize;
i += channels, ++byteCount) {
d3 = d2;
d2 = fromUnsigned32ToSigned32(prevDelta - d1);
d1 = fromUnsigned32ToSigned32(prevDelta);
let predicted = fromSigned32ToUnsigned32(8*prevByte + k1*d1 + k2*d2 + k3*d3); // uint
predicted = (predicted >>> 3) & 0xff;
let curByte = this.mem_[srcOffset++]; // uint
// Predicted-=CurByte;
predicted = fromSigned32ToUnsigned32(predicted - curByte);
this.mem_[destOffset + i] = (predicted & 0xff);
// PrevDelta=(signed char)(Predicted-PrevByte);
// where Predicted, PrevByte, PrevDelta are all unsigned int (32)
// casting this subtraction to a (signed char) is kind of invalid
// but it does the following:
// - do the subtraction
// - get the bottom 8 bits of the result
// - if it was >= 0x80, then the value is negative (subtract 0x100)
// - if the value is now negative, add 0x100000000 to make unsigned
//
// Example:
// predicted = 101
// prevByte = 4294967158
// (predicted - prevByte) = -4294967057
// take lower 8 bits: 1110 1111 = 239
// since > 127, subtract 256 = -17
// since < 0, add 0x100000000 = 4294967279
prevDelta = fromSigned32ToUnsigned32(
fromUnsigned8ToSigned8((predicted - prevByte) & 0xff));
prevByte = predicted;
// int D=((signed char)CurByte)<<3;
let curByteAsSignedChar = fromUnsigned8ToSigned8(curByte); // signed char
let d = (curByteAsSignedChar << 3);
dif[0] += Math.abs(d);
dif[1] += Math.abs(d-d1);
dif[2] += Math.abs(d+d1);
dif[3] += Math.abs(d-d2);
dif[4] += Math.abs(d+d2);
dif[5] += Math.abs(d-d3);
dif[6] += Math.abs(d+d3);
if ((byteCount & 0x1f) == 0) {
let minDif = dif[0], numMinDif = 0;
dif[0] = 0;
for (let j = 1; j < 7; ++j) {
if (dif[j] < minDif) {
minDif = dif[j];
numMinDif = j;
}
dif[j] = 0;
}
switch (numMinDif) {
case 1: if (k1>=-16) k1--; break;
case 2: if (k1 < 16) k1++; break;
case 3: if (k2>=-16) k2--; break;
case 4: if (k2 < 16) k2++; break;
case 5: if (k3>=-16) k3--; break;
case 6: if (k3 < 16) k3++; break;
}
}
}
}
break;
}
case VM_StandardFilters.VMSF_DELTA: {
const dataSize = this.R_[4];
const channels = this.R_[0];
let srcPos = 0;
const border = dataSize * 2;
//SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
const dataView = new DataView(this.mem_.buffer, VM_GLOBALMEMADDR);
dataView.setUint32(0x20 /* byte offset */,
dataSize /* value */,
true /* little endian */);
if (dataSize >= VM_GLOBALMEMADDR / 2) {
break;
}
// Bytes from same channels are grouped to continual data blocks,
// so we need to place them back to their interleaving positions.
for (let curChannel = 0; curChannel < channels; ++curChannel) {
let prevByte = 0;
for (let destPos = dataSize + curChannel; destPos < border; destPos += channels) {
prevByte = (prevByte - this.mem_[srcPos++]) & 0xff;
this.mem_[destPos] = prevByte;
}
}
break;
}
default:
console.error('RarVM Standard Filter not supported: ' + getDebugString(VM_StandardFilters, filterType));
break;
}
}
/**
* @param {Uint8Array} code
* @param {VM_PreparedProgram} prg
*/
prepare(code, prg) {
let codeSize = code.length;
//InitBitInput();
//memcpy(InBuf,Code,Min(CodeSize,BitInput::MAX_SIZE));
const bstream = new bitjs.io.BitStream(code.buffer, true /* rtl */);
// Calculate the single byte XOR checksum to check validity of VM code.
let xorSum = 0;
for (let i = 1; i < codeSize; ++i) {
xorSum ^= code[i];
}
bstream.readBits(8);
prg.Cmd = []; // TODO: Is this right? I don't see it being done in rarvm.cpp.
// VM code is valid if equal.
if (xorSum == code[0]) {
const filterType = this.isStandardFilter(code);
if (filterType != VM_StandardFilters.VMSF_NONE) {
// VM code is found among standard filters.
const curCmd = new VM_PreparedCommand();
prg.Cmd.push(curCmd);
curCmd.OpCode = VM_Commands.VM_STANDARD;
curCmd.Op1.Data = filterType;
// TODO: Addr=&CurCmd->Op1.Data
curCmd.Op1.Addr = [curCmd.Op1.Data];
curCmd.Op2.Addr = [null]; // &CurCmd->Op2.Data;
curCmd.Op1.Type = VM_OpType.VM_OPNONE;
curCmd.Op2.Type = VM_OpType.VM_OPNONE;
codeSize = 0;
}
const dataFlag = bstream.readBits(1);
// Read static data contained in DB operators. This data cannot be
// changed, it is a part of VM code, not a filter parameter.
if (dataFlag & 0x8000) {
const dataSize = RarVM.readData(bstream) + 1;
// TODO: This accesses the byte pointer of the bstream directly. Is that ok?
for (let i = 0; i < bstream.bytePtr < codeSize && i < dataSize; ++i) {
// Append a byte to the program's static data.
const newStaticData = new Uint8Array(prg.StaticData.length + 1);
newStaticData.set(prg.StaticData);
newStaticData[newStaticData.length - 1] = bstream.readBits(8);
prg.StaticData = newStaticData;
}
}
while (bstream.bytePtr < codeSize) {
const curCmd = new VM_PreparedCommand();
prg.Cmd.push(curCmd); // Prg->Cmd.Add(1)
const flag = bstream.peekBits(1);
if (!flag) { // (Data&0x8000)==0
curCmd.OpCode = bstream.readBits(4);
} else {
curCmd.OpCode = (bstream.readBits(6) - 24);
}
if (VM_CmdFlags[curCmd.OpCode] & VMCF_BYTEMODE) {
curCmd.ByteMode = (bstream.readBits(1) != 0);
} else {
curCmd.ByteMode = 0;
}
curCmd.Op1.Type = VM_OpType.VM_OPNONE;
curCmd.Op2.Type = VM_OpType.VM_OPNONE;
const opNum = (VM_CmdFlags[curCmd.OpCode] & VMCF_OPMASK);
curCmd.Op1.Addr = null;
curCmd.Op2.Addr = null;
if (opNum > 0) {
this.decodeArg(curCmd.Op1, curCmd.ByteMode, bstream); // reading the first operand
if (opNum == 2) {
this.decodeArg(curCmd.Op2, curCmd.ByteMode, bstream); // reading the second operand
} else {
if (curCmd.Op1.Type == VM_OpType.VM_OPINT && (VM_CmdFlags[curCmd.OpCode] & (VMCF_JUMP|VMCF_PROC))) {
// Calculating jump distance.
let distance = curCmd.Op1.Data;
if (distance >= 256) {
distance -= 256;
} else {
if (distance >= 136) {
distance -= 264;
} else {
if (distance >= 16) {
distance -= 8;
} else {
if (distance >= 8) {
distance -= 16;
}
}
}
distance += prg.Cmd.length;
}
curCmd.Op1.Data = distance;
}
}
} // if (OpNum>0)
} // while ((uint)InAddr<CodeSize)
} // if (XorSum==Code[0])
const curCmd = new VM_PreparedCommand();
prg.Cmd.push(curCmd);
curCmd.OpCode = VM_Commands.VM_RET;
// TODO: Addr=&CurCmd->Op1.Data
curCmd.Op1.Addr = [curCmd.Op1.Data];
curCmd.Op2.Addr = [curCmd.Op2.Data];
curCmd.Op1.Type = VM_OpType.VM_OPNONE;
curCmd.Op2.Type = VM_OpType.VM_OPNONE;
// If operand 'Addr' field has not been set by DecodeArg calls above,
// let's set it to point to operand 'Data' field. It is necessary for
// VM_OPINT type operands (usual integers) or maybe if something was
// not set properly for other operands. 'Addr' field is required
// for quicker addressing of operand data.
for (let i = 0; i < prg.Cmd.length; ++i) {
const cmd = prg.Cmd[i];
if (cmd.Op1.Addr == null) {
cmd.Op1.Addr = [cmd.Op1.Data];
}
if (cmd.Op2.Addr == null) {
cmd.Op2.Addr = [cmd.Op2.Data];
}
}
/*
#ifdef VM_OPTIMIZE
if (CodeSize!=0)
Optimize(Prg);
#endif
*/
}
/**
* @param {Uint8Array} arr The byte array to set a value in.
* @param {number} value The unsigned 32-bit value to set.
* @param {number} offset Offset into arr to start setting the value, defaults to 0.
*/
setLowEndianValue(arr, value, offset) {
const i = offset || 0;
arr[i] = value & 0xff;
arr[i + 1] = (value >>> 8) & 0xff;
arr[i + 2] = (value >>> 16) & 0xff;
arr[i + 3] = (value >>> 24) & 0xff;
}
/**
* Sets a number of bytes of the VM memory at the given position from a
* source buffer of bytes.
* @param {number} pos The position in the VM memory to start writing to.
* @param {Uint8Array} buffer The source buffer of bytes.
* @param {number} dataSize The number of bytes to set.
*/
setMemory(pos, buffer, dataSize) {
if (pos < VM_MEMSIZE) {
const numBytes = Math.min(dataSize, VM_MEMSIZE - pos);
for (let i = 0; i < numBytes; ++i) {
this.mem_[pos + i] = buffer[i];
}
}
}
/**
* Static function that reads in the next set of bits for the VM
* (might return 4, 8, 16 or 32 bits).
* @param {bitjs.io.BitStream} bstream A RTL bit stream.
* @return {number} The value of the bits read.
*/
static readData(bstream) {
// Read in the first 2 bits.
const flags = bstream.readBits(2);
switch (flags) { // Data&0xc000
// Return the next 4 bits.
case 0:
return bstream.readBits(4); // (Data>>10)&0xf
case 1: // 0x4000
// 0x3c00 => 0011 1100 0000 0000
if (bstream.peekBits(4) == 0) { // (Data&0x3c00)==0
// Skip the 4 zero bits.
bstream.readBits(4);
// Read in the next 8 and pad with 1s to 32 bits.
return (0xffffff00 | bstream.readBits(8)) >>> 0; // ((Data>>2)&0xff)
}
// Else, read in the next 8.
return bstream.readBits(8);
// Read in the next 16.
case 2: // 0x8000
const val = bstream.getBits();
bstream.readBits(16);
return val; //bstream.readBits(16);
// case 3
default:
return (bstream.readBits(16) << 16) | bstream.readBits(16);
}
}
}
// ============================================================================================== //
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