Python interpreter runs .py files in 2 step process: first, it produces bytecode, which it then executes. Translation of .py source into bytecode is time-consuming, so Python dumps compiled bytecode into .pyc files, to be reused from cache at later time if possible.
.pyc file is essentially a raw dump of py_object (see body) with
a simple header prepended.
This page hosts a formal specification of .pyc file format of Python using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for C# generated by Kaitai Struct depends on the C# runtime library. You have to install it before you can parse data.
The C# runtime library is available in the NuGet Gallery. Installation instructions can also be found there.
Parse a local file and get structure in memory:
var data = PythonPyc27.FromFile("path/to/local/file.pyc");
Or parse structure from a byte array:
byte[] someArray = new byte[] { ... };
var data = new PythonPyc27(new KaitaiStream(someArray));
After that, one can get various attributes from the structure by accessing properties like:
data.VersionMagic // => get version magic
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
using System.Collections.Generic;
namespace Kaitai
{
/// <summary>
/// Python interpreter runs .py files in 2 step process: first, it
/// produces bytecode, which it then executes. Translation of .py source
/// into bytecode is time-consuming, so Python dumps compiled bytecode
/// into .pyc files, to be reused from cache at later time if possible.
///
/// .pyc file is essentially a raw dump of `py_object` (see `body`) with
/// a simple header prepended.
/// </summary>
public partial class PythonPyc27 : KaitaiStruct
{
public static PythonPyc27 FromFile(string fileName)
{
return new PythonPyc27(new KaitaiStream(fileName));
}
public enum Version
{
V15 = 20121,
V16 = 50428,
V20 = 50823,
V21 = 60202,
V22 = 60717,
V23A0 = 62011,
V23A0b = 62021,
V24A0 = 62041,
V24A3 = 62051,
V24B1 = 62061,
V25A0 = 62071,
V25A0b = 62081,
V25A0c = 62091,
V25A0d = 62092,
V25B3 = 62101,
V25B3b = 62111,
V25C1 = 62121,
V25C2 = 62131,
V26A0 = 62151,
V26A1 = 62161,
V27A0 = 62171,
V27A0b = 62181,
V27A0c = 62191,
V27A0d = 62201,
V27A0e = 62211,
}
public PythonPyc27(KaitaiStream p__io, KaitaiStruct p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root ?? this;
_read();
}
private void _read()
{
_versionMagic = ((Version) m_io.ReadU2le());
_crlf = m_io.ReadU2le();
_modificationTimestamp = m_io.ReadU4le();
_body = new PyObject(m_io, this, m_root);
}
public partial class CodeObject : KaitaiStruct
{
public static CodeObject FromFile(string fileName)
{
return new CodeObject(new KaitaiStream(fileName));
}
public enum FlagsEnum
{
HasArgs = 4,
HasKwargs = 8,
Generator = 32,
}
public CodeObject(KaitaiStream p__io, PythonPyc27.PyObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_argCount = m_io.ReadU4le();
_localCount = m_io.ReadU4le();
_stackSize = m_io.ReadU4le();
_flags = ((FlagsEnum) m_io.ReadU4le());
_code = new Assembly(m_io, this, m_root);
_consts = new PyObject(m_io, this, m_root);
_names = new PyObject(m_io, this, m_root);
_varNames = new PyObject(m_io, this, m_root);
_freeVars = new PyObject(m_io, this, m_root);
_cellVars = new PyObject(m_io, this, m_root);
_filename = new PyObject(m_io, this, m_root);
_name = new PyObject(m_io, this, m_root);
_firstLineNo = m_io.ReadU4le();
_lnotab = new PyObject(m_io, this, m_root);
}
private uint _argCount;
private uint _localCount;
private uint _stackSize;
private FlagsEnum _flags;
private Assembly _code;
private PyObject _consts;
private PyObject _names;
private PyObject _varNames;
private PyObject _freeVars;
private PyObject _cellVars;
private PyObject _filename;
private PyObject _name;
private uint _firstLineNo;
private PyObject _lnotab;
private PythonPyc27 m_root;
private PythonPyc27.PyObject m_parent;
public uint ArgCount { get { return _argCount; } }
public uint LocalCount { get { return _localCount; } }
public uint StackSize { get { return _stackSize; } }
public FlagsEnum Flags { get { return _flags; } }
public Assembly Code { get { return _code; } }
public PyObject Consts { get { return _consts; } }
public PyObject Names { get { return _names; } }
public PyObject VarNames { get { return _varNames; } }
public PyObject FreeVars { get { return _freeVars; } }
public PyObject CellVars { get { return _cellVars; } }
public PyObject Filename { get { return _filename; } }
public PyObject Name { get { return _name; } }
public uint FirstLineNo { get { return _firstLineNo; } }
public PyObject Lnotab { get { return _lnotab; } }
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.PyObject M_Parent { get { return m_parent; } }
}
public partial class Assembly : KaitaiStruct
{
public static Assembly FromFile(string fileName)
{
return new Assembly(new KaitaiStream(fileName));
}
public Assembly(KaitaiStream p__io, PythonPyc27.CodeObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_stringMagic = m_io.ReadBytes(1);
if (!((KaitaiStream.ByteArrayCompare(StringMagic, new byte[] { 115 }) == 0)))
{
throw new ValidationNotEqualError(new byte[] { 115 }, StringMagic, M_Io, "/types/assembly/seq/0");
}
_length = m_io.ReadU4le();
__raw_items = m_io.ReadBytes(Length);
var io___raw_items = new KaitaiStream(__raw_items);
_items = new OpArgs(io___raw_items, this, m_root);
}
private byte[] _stringMagic;
private uint _length;
private OpArgs _items;
private PythonPyc27 m_root;
private PythonPyc27.CodeObject m_parent;
private byte[] __raw_items;
public byte[] StringMagic { get { return _stringMagic; } }
public uint Length { get { return _length; } }
public OpArgs Items { get { return _items; } }
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.CodeObject M_Parent { get { return m_parent; } }
public byte[] M_RawItems { get { return __raw_items; } }
}
public partial class OpArg : KaitaiStruct
{
public static OpArg FromFile(string fileName)
{
return new OpArg(new KaitaiStream(fileName));
}
public enum OpCodeEnum
{
StopCode = 0,
PopTop = 1,
RotTwo = 2,
RotThree = 3,
DupTop = 4,
RotFour = 5,
Nop = 9,
UnaryPositive = 10,
UnaryNegative = 11,
UnaryNot = 12,
UnaryConvert = 13,
UnaryInvert = 15,
BinaryPower = 19,
BinaryMultiply = 20,
BinaryDivide = 21,
BinaryModulo = 22,
BinaryAdd = 23,
BinarySubtract = 24,
BinarySubscr = 25,
BinaryFloorDivide = 26,
BinaryTrueDivide = 27,
InplaceFloorDivide = 28,
InplaceTrueDivide = 29,
Slice0 = 30,
Slice1 = 31,
Slice2 = 32,
Slice3 = 33,
StoreSlice0 = 40,
StoreSlice1 = 41,
StoreSlice2 = 42,
StoreSlice3 = 43,
DeleteSlice0 = 50,
DeleteSlice1 = 51,
DeleteSlice2 = 52,
DeleteSlice3 = 53,
StoreMap = 54,
InplaceAdd = 55,
InplaceSubtract = 56,
InplaceMultiply = 57,
InplaceDivide = 58,
InplaceModulo = 59,
StoreSubscr = 60,
DeleteSubscr = 61,
BinaryLshift = 62,
BinaryRshift = 63,
BinaryAnd = 64,
BinaryXor = 65,
BinaryOr = 66,
InplacePower = 67,
GetIter = 68,
PrintExpr = 70,
PrintItem = 71,
PrintNewline = 72,
PrintItemTo = 73,
PrintNewlineTo = 74,
InplaceLshift = 75,
InplaceRshift = 76,
InplaceAnd = 77,
InplaceXor = 78,
InplaceOr = 79,
BreakLoop = 80,
WithCleanup = 81,
LoadLocals = 82,
ReturnValue = 83,
ImportStar = 84,
ExecStmt = 85,
YieldValue = 86,
PopBlock = 87,
EndFinally = 88,
BuildClass = 89,
StoreName = 90,
DeleteName = 91,
UnpackSequence = 92,
ForIter = 93,
ListAppend = 94,
StoreAttr = 95,
DeleteAttr = 96,
StoreGlobal = 97,
DeleteGlobal = 98,
DupTopx = 99,
LoadConst = 100,
LoadName = 101,
BuildTuple = 102,
BuildList = 103,
BuildSet = 104,
BuildMap = 105,
LoadAttr = 106,
CompareOp = 107,
ImportName = 108,
ImportFrom = 109,
JumpForward = 110,
JumpIfFalseOrPop = 111,
JumpIfTrueOrPop = 112,
JumpAbsolute = 113,
PopJumpIfFalse = 114,
PopJumpIfTrue = 115,
LoadGlobal = 116,
ContinueLoop = 119,
SetupLoop = 120,
SetupExcept = 121,
SetupFinally = 122,
LoadFast = 124,
StoreFast = 125,
DeleteFast = 126,
RaiseVarargs = 130,
CallFunction = 131,
MakeFunction = 132,
BuildSlice = 133,
MakeClosure = 134,
LoadClosure = 135,
LoadDeref = 136,
StoreDeref = 137,
CallFunctionVar = 140,
CallFunctionKw = 141,
CallFunctionVarKw = 142,
SetupWith = 143,
ExtendedArg = 145,
SetAdd = 146,
MapAdd = 147,
}
public OpArg(KaitaiStream p__io, PythonPyc27.OpArgs p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_opCode = ((OpCodeEnum) m_io.ReadU1());
if (OpCode >= OpCodeEnum.StoreName) {
_arg = m_io.ReadU2le();
}
}
private OpCodeEnum _opCode;
private ushort? _arg;
private PythonPyc27 m_root;
private PythonPyc27.OpArgs m_parent;
public OpCodeEnum OpCode { get { return _opCode; } }
public ushort? Arg { get { return _arg; } }
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.OpArgs M_Parent { get { return m_parent; } }
}
public partial class PyObject : KaitaiStruct
{
public static PyObject FromFile(string fileName)
{
return new PyObject(new KaitaiStream(fileName));
}
public enum ObjectType
{
Tuple = 40,
PyFalse = 70,
None = 78,
StringRef = 82,
PyTrue = 84,
CodeObject = 99,
Int = 105,
String = 115,
Interned = 116,
UnicodeString = 117,
}
public PyObject(KaitaiStream p__io, KaitaiStruct p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_type = ((ObjectType) m_io.ReadU1());
switch (Type) {
case ObjectType.String: {
_value = new PyString(m_io, this, m_root);
break;
}
case ObjectType.Tuple: {
_value = new Tuple(m_io, this, m_root);
break;
}
case ObjectType.Int: {
_value = m_io.ReadU4le();
break;
}
case ObjectType.PyTrue: {
_value = new PyTrue(m_io, this, m_root);
break;
}
case ObjectType.PyFalse: {
_value = new PyFalse(m_io, this, m_root);
break;
}
case ObjectType.None: {
_value = new PyNone(m_io, this, m_root);
break;
}
case ObjectType.StringRef: {
_value = new StringRef(m_io, this, m_root);
break;
}
case ObjectType.CodeObject: {
_value = new CodeObject(m_io, this, m_root);
break;
}
case ObjectType.Interned: {
_value = new InternedString(m_io, this, m_root);
break;
}
}
}
public partial class PyNone : KaitaiStruct
{
public static PyNone FromFile(string fileName)
{
return new PyNone(new KaitaiStream(fileName));
}
public PyNone(KaitaiStream p__io, PythonPyc27.PyObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
}
private PythonPyc27 m_root;
private PythonPyc27.PyObject m_parent;
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.PyObject M_Parent { get { return m_parent; } }
}
public partial class PyFalse : KaitaiStruct
{
public static PyFalse FromFile(string fileName)
{
return new PyFalse(new KaitaiStream(fileName));
}
public PyFalse(KaitaiStream p__io, PythonPyc27.PyObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
}
private PythonPyc27 m_root;
private PythonPyc27.PyObject m_parent;
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.PyObject M_Parent { get { return m_parent; } }
}
public partial class StringRef : KaitaiStruct
{
public static StringRef FromFile(string fileName)
{
return new StringRef(new KaitaiStream(fileName));
}
public StringRef(KaitaiStream p__io, PythonPyc27.PyObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_internedListIndex = m_io.ReadU4le();
}
private uint _internedListIndex;
private PythonPyc27 m_root;
private PythonPyc27.PyObject m_parent;
public uint InternedListIndex { get { return _internedListIndex; } }
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.PyObject M_Parent { get { return m_parent; } }
}
public partial class PyTrue : KaitaiStruct
{
public static PyTrue FromFile(string fileName)
{
return new PyTrue(new KaitaiStream(fileName));
}
public PyTrue(KaitaiStream p__io, PythonPyc27.PyObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
}
private PythonPyc27 m_root;
private PythonPyc27.PyObject m_parent;
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.PyObject M_Parent { get { return m_parent; } }
}
public partial class Tuple : KaitaiStruct
{
public static Tuple FromFile(string fileName)
{
return new Tuple(new KaitaiStream(fileName));
}
public Tuple(KaitaiStream p__io, PythonPyc27.PyObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_count = m_io.ReadU4le();
_items = new List<PyObject>();
for (var i = 0; i < Count; i++)
{
_items.Add(new PyObject(m_io, this, m_root));
}
}
private uint _count;
private List<PyObject> _items;
private PythonPyc27 m_root;
private PythonPyc27.PyObject m_parent;
public uint Count { get { return _count; } }
public List<PyObject> Items { get { return _items; } }
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.PyObject M_Parent { get { return m_parent; } }
}
public partial class UnicodeString : KaitaiStruct
{
public static UnicodeString FromFile(string fileName)
{
return new UnicodeString(new KaitaiStream(fileName));
}
public UnicodeString(KaitaiStream p__io, KaitaiStruct p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_length = m_io.ReadU4le();
_data = System.Text.Encoding.GetEncoding("utf-8").GetString(m_io.ReadBytes(Length));
}
private uint _length;
private string _data;
private PythonPyc27 m_root;
private KaitaiStruct m_parent;
public uint Length { get { return _length; } }
public string Data { get { return _data; } }
public PythonPyc27 M_Root { get { return m_root; } }
public KaitaiStruct M_Parent { get { return m_parent; } }
}
public partial class InternedString : KaitaiStruct
{
public static InternedString FromFile(string fileName)
{
return new InternedString(new KaitaiStream(fileName));
}
public InternedString(KaitaiStream p__io, PythonPyc27.PyObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_length = m_io.ReadU4le();
_data = System.Text.Encoding.GetEncoding("utf-8").GetString(m_io.ReadBytes(Length));
}
private uint _length;
private string _data;
private PythonPyc27 m_root;
private PythonPyc27.PyObject m_parent;
public uint Length { get { return _length; } }
public string Data { get { return _data; } }
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.PyObject M_Parent { get { return m_parent; } }
}
public partial class PyString : KaitaiStruct
{
public static PyString FromFile(string fileName)
{
return new PyString(new KaitaiStream(fileName));
}
public PyString(KaitaiStream p__io, PythonPyc27.PyObject p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_length = m_io.ReadU4le();
_data = m_io.ReadBytes(Length);
}
private uint _length;
private byte[] _data;
private PythonPyc27 m_root;
private PythonPyc27.PyObject m_parent;
public uint Length { get { return _length; } }
public byte[] Data { get { return _data; } }
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.PyObject M_Parent { get { return m_parent; } }
}
private ObjectType _type;
private object _value;
private PythonPyc27 m_root;
private KaitaiStruct m_parent;
public ObjectType Type { get { return _type; } }
public object Value { get { return _value; } }
public PythonPyc27 M_Root { get { return m_root; } }
public KaitaiStruct M_Parent { get { return m_parent; } }
}
public partial class OpArgs : KaitaiStruct
{
public static OpArgs FromFile(string fileName)
{
return new OpArgs(new KaitaiStream(fileName));
}
public OpArgs(KaitaiStream p__io, PythonPyc27.Assembly p__parent = null, PythonPyc27 p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_items = new List<OpArg>();
{
var i = 0;
while (!m_io.IsEof) {
_items.Add(new OpArg(m_io, this, m_root));
i++;
}
}
}
private List<OpArg> _items;
private PythonPyc27 m_root;
private PythonPyc27.Assembly m_parent;
public List<OpArg> Items { get { return _items; } }
public PythonPyc27 M_Root { get { return m_root; } }
public PythonPyc27.Assembly M_Parent { get { return m_parent; } }
}
private Version _versionMagic;
private ushort _crlf;
private uint _modificationTimestamp;
private PyObject _body;
private PythonPyc27 m_root;
private KaitaiStruct m_parent;
public Version VersionMagic { get { return _versionMagic; } }
public ushort Crlf { get { return _crlf; } }
public uint ModificationTimestamp { get { return _modificationTimestamp; } }
public PyObject Body { get { return _body; } }
public PythonPyc27 M_Root { get { return m_root; } }
public KaitaiStruct M_Parent { get { return m_parent; } }
}
}