gpython/stdlib/marshal/marshal.go at main · go-python/gpython · GitHub

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// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

// Implement unmarshal and marshal

package marshal

import (

"encoding/binary"

"errors"

"fmt"

"io"

"math/big"

"strconv"

"github.com/go-python/gpython/py"

)

const (

MARSHAL_VERSION = 3

TYPE_NULL = '0'

TYPE_NONE = 'N'

TYPE_FALSE = 'F'

TYPE_TRUE = 'T'

TYPE_STOPITER = 'S'

TYPE_ELLIPSIS = '.'

TYPE_INT = 'i'

TYPE_FLOAT = 'f'

TYPE_BINARY_FLOAT = 'g'

TYPE_COMPLEX = 'x'

TYPE_BINARY_COMPLEX = 'y'

TYPE_LONG = 'l'

TYPE_STRING = 's'

TYPE_INTERNED = 't'

TYPE_REF = 'r'

TYPE_TUPLE = '('

TYPE_LIST = '['

TYPE_DICT = '{'

TYPE_CODE = 'c'

TYPE_UNICODE = 'u'

TYPE_UNKNOWN = '?'

TYPE_SET = '<'

TYPE_FROZENSET = '>'

FLAG_REF = 0x80 // with a type, add obj to index

SIZE32_MAX = 0x7FFFFFFF

TYPE_ASCII = 'a'

TYPE_ASCII_INTERNED = 'A'

TYPE_SMALL_TUPLE = ')'

TYPE_SHORT_ASCII = 'z'

TYPE_SHORT_ASCII_INTERNED = 'Z'

// We assume that Python ints are stored internally in base some power of

// 2**15; for the sake of portability we'll always read and write them in base

// exactly 2**15.

PyLong_MARSHAL_SHIFT = 15

PyLong_MARSHAL_BASE = (1 << PyLong_MARSHAL_SHIFT)

PyLong_MARSHAL_MASK = (PyLong_MARSHAL_BASE - 1)

)

// Represents currently being unmarshalled file

type rFile struct {

r io.Reader

refs []py.Object

}

// Reads an object from the input

func (rfile *rFile) ReadObject() (obj py.Object, err error) {

var code byte

// defer func() { fmt.Printf("ReadObject(%c) returning %#v with error %v\n", code, obj, err) }()

err = binary.Read(rfile.r, binary.LittleEndian, &code)

if err != nil {

return

}

AddRef := (code & FLAG_REF) != 0

Type := code &^ FLAG_REF

// Add a reference if required

addRef := func(obj py.Object) py.Object {

if AddRef {

rfile.refs = append(rfile.refs, obj)

}

return obj

}

// Reserve a reference if required

reserveRef := func() int {

if !AddRef {

return -1

}

rfile.refs = append(rfile.refs, nil)

return len(rfile.refs) - 1

}

// Update a ref if required

updateRef := func(i int, obj py.Object) py.Object {

if i >= 0 {

rfile.refs[i] = obj

}

return obj

}

switch Type {

case TYPE_NULL:

// A null object

AddRef = false

return nil, nil

case TYPE_NONE:

// The Python None object

AddRef = false

return py.None, nil

case TYPE_FALSE:

// The python False object

AddRef = false

return py.False, nil

case TYPE_TRUE:

// The python True object

AddRef = false

return py.True, nil

case TYPE_STOPITER:

// The python StopIteration Exception

AddRef = false

return py.StopIteration, nil

case TYPE_ELLIPSIS:

// The python elipsis object

AddRef = false

return py.Ellipsis, nil

case TYPE_INT:

// 4 bytes of signed integer

var n int32

err = binary.Read(rfile.r, binary.LittleEndian, &n)

if err != nil {

return

}

return addRef(py.Int(n)), nil

case TYPE_FLOAT:

// Floating point number as a string

var length uint8

err = binary.Read(rfile.r, binary.LittleEndian, &length)

if err != nil {

return

}

buf := make([]byte, int(length))

_, err = io.ReadFull(rfile.r, buf)

if err != nil {

return

}

var f float64

f, err = strconv.ParseFloat(string(buf), 64)

if err != nil {

return

}

return addRef(py.Float(f)), nil

case TYPE_BINARY_FLOAT:

var f float64

err = binary.Read(rfile.r, binary.LittleEndian, &f)

if err != nil {

return

}

return addRef(py.Float(f)), nil

case TYPE_COMPLEX:

// Complex number as a string

// FIXME this is using Go conversion not Python conversion which may differ

var length uint8

err = binary.Read(rfile.r, binary.LittleEndian, &length)

if err != nil {

return

}

buf := make([]byte, int(length))

_, err = io.ReadFull(rfile.r, buf)

if err != nil {

return

}

var c complex128

// FIXME c, err = strconv.ParseComplex(string(buf), 64)

if err != nil {

return

}

return addRef(py.Complex(c)), nil

case TYPE_BINARY_COMPLEX:

var c complex128

err = binary.Read(rfile.r, binary.LittleEndian, &c)

if err != nil {

return

}

return addRef(py.Complex(c)), nil

case TYPE_LONG:

var size int32

err = binary.Read(rfile.r, binary.LittleEndian, &size)

if err != nil {

return

}

// FIXME negative := false

if size < 0 {

// FIXME negative = true

size = -size

}

if size < 0 || size > SIZE32_MAX {

return nil, errors.New("bad marshal data (long size out of range)")

}

// FIXME not sure what -ve size means!

// Now read shorts which have 15 bits of the number in

digits := make([]int16, size)

err = binary.Read(rfile.r, binary.LittleEndian, &digits)

if err != nil {

return

}

if digits[0] == 0 {

// FIXME should be ValueError

return nil, errors.New("bad marshal data (digit out of range in long)")

}

// Convert into a big.Int

r := new(big.Int)

t := new(big.Int)

for _, digit := range digits {

r.Lsh(r, 15)

t.SetInt64(int64(digit))

r.Add(r, t)

}

// FIXME try to fit into int64 if possible

return addRef((*py.BigInt)(r)), nil

case TYPE_STRING, TYPE_INTERNED, TYPE_UNICODE, TYPE_ASCII, TYPE_ASCII_INTERNED:

var size int32

err = binary.Read(rfile.r, binary.LittleEndian, &size)

if err != nil {

return

}

if size < 0 || size > SIZE32_MAX {

return nil, errors.New("bad marshal data (string size out of range)")

}

buf := make([]byte, int(size))

_, err = io.ReadFull(rfile.r, buf)

if err != nil {

return

}

// FIXME do something different for unicode & interned?

return addRef(py.String(buf)), nil

case TYPE_SHORT_ASCII, TYPE_SHORT_ASCII_INTERNED:

var size uint8

err = binary.Read(rfile.r, binary.LittleEndian, &size)

if err != nil {

return

}

buf := make([]byte, int(size))

_, err = io.ReadFull(rfile.r, buf)

if err != nil {

return

}

// FIXME do something different for interned?

return addRef(py.String(buf)), nil

case TYPE_TUPLE, TYPE_LIST, TYPE_SET, TYPE_FROZENSET:

var size int32

err = binary.Read(rfile.r, binary.LittleEndian, &size)

if err != nil {

return

}

if size < 0 || size > SIZE32_MAX {

return nil, errors.New("bad marshal data (tuple size out of range)")

}

tuple := make([]py.Object, int(size))

iref := reserveRef()

for i := range tuple {

tuple[i], err = rfile.ReadObject()

if err != nil {

return

}

switch Type {

case TYPE_TUPLE:

return updateRef(iref, py.Tuple(tuple)), nil

case TYPE_LIST:

return updateRef(iref, py.NewListFromItems(tuple)), nil

case TYPE_SET:

return updateRef(iref, py.NewSetFromItems(tuple)), nil

case TYPE_FROZENSET:

return updateRef(iref, py.NewFrozenSetFromItems(tuple)), nil

}

case TYPE_SMALL_TUPLE:

var size uint8

err = binary.Read(rfile.r, binary.LittleEndian, &size)

if err != nil {

return

}

tuple := make([]py.Object, int(size))

iref := reserveRef()

for i := range tuple {

tuple[i], err = rfile.ReadObject()

if err != nil {

return

}

return updateRef(iref, py.Tuple(tuple)), nil

case TYPE_DICT:

// FIXME should be py.Dict

dict := py.NewStringDict()

iref := reserveRef()

var key, value py.Object

for {

key, err = rfile.ReadObject()

if err != nil {

return

}

if key == nil {

break

}

value, err = rfile.ReadObject()

if err != nil {

return

}

if value != nil {

// FIXME should be objects as key

dict[string(key.(py.String))] = value

}

return updateRef(iref, dict), nil

case TYPE_REF:

// Reference to a previous read

var n int32

err = binary.Read(rfile.r, binary.LittleEndian, &n)

if err != nil {

return

}

if n < 0 || int(n) >= len(rfile.refs) {

AddRef = false

fmt.Printf("Returning None as %d/%d out of range\n", n, len(rfile.refs))

return py.None, nil

// return nil, fmt.Errorf("TYPE_REF (out of range) - %d vs %d: %#v", n, len(rfile.refs), rfile.refs)

}

AddRef = false

return rfile.refs[n], nil

case TYPE_CODE:

var argcount int32

var kwonlyargcount int32

var nlocals int32

var stacksize int32

var flags int32

var code py.Object

var consts py.Object

var names py.Object

var varnames py.Object

var freevars py.Object

var cellvars py.Object

var filename py.Object

var name py.Object

var firstlineno int32

var lnotab py.Object

iref := reserveRef()

if err = binary.Read(rfile.r, binary.LittleEndian, &argcount); err != nil {

return

}

if err = binary.Read(rfile.r, binary.LittleEndian, &kwonlyargcount); err != nil {

return

}

if err = binary.Read(rfile.r, binary.LittleEndian, &nlocals); err != nil {

return

}

if err = binary.Read(rfile.r, binary.LittleEndian, &stacksize); err != nil {

return

}

if err = binary.Read(rfile.r, binary.LittleEndian, &flags); err != nil {

return

}

if code, err = rfile.ReadObject(); err != nil {

return

}

if consts, err = rfile.ReadObject(); err != nil {

return

}

if names, err = rfile.ReadObject(); err != nil {

return

}

if varnames, err = rfile.ReadObject(); err != nil {

return

}

if freevars, err = rfile.ReadObject(); err != nil {

return

}

if cellvars, err = rfile.ReadObject(); err != nil {

return

}

if filename, err = rfile.ReadObject(); err != nil {

return

}

if name, err = rfile.ReadObject(); err != nil {

return

}

if err = binary.Read(rfile.r, binary.LittleEndian, &firstlineno); err != nil {

return

}

if lnotab, err = rfile.ReadObject(); err != nil {

return

}

// fmt.Printf("argcount = %v\n", argcount)

// fmt.Printf("kwonlyargcount = %v\n", kwonlyargcount)

// fmt.Printf("nlocals = %v\n", nlocals)

// fmt.Printf("stacksize = %v\n", stacksize)

// fmt.Printf("flags = %v\n", flags)

// fmt.Printf("code = %x\n", code)

// fmt.Printf("consts = %v\n", consts)

// fmt.Printf("names = %v\n", names)

// fmt.Printf("varnames = %v\n", varnames)

// fmt.Printf("freevars = %v\n", freevars)

// fmt.Printf("cellvars = %v\n", cellvars)

// fmt.Printf("filename = %v\n", filename)

// fmt.Printf("name = %v\n", name)

// fmt.Printf("firstlineno = %v\n", firstlineno)

// fmt.Printf("lnotab = %x\n", lnotab)

v := py.NewCode(

argcount, kwonlyargcount,

nlocals, stacksize, flags,

code, consts, names, varnames,

freevars, cellvars, filename, name,

firstlineno, lnotab)

return updateRef(iref, v), nil

default:

return nil, fmt.Errorf("bad marshal data (unknown type code) 0x%02X '%c'", Type, Type)

}

return

}

// Reads an object from the input

func ReadObject(r io.Reader) (obj py.Object, err error) {

rfile := &rFile{r: r}

return rfile.ReadObject()

}

// The header on a .pyc file

type PycHeader struct {

Magic uint32

Timestamp int32

Length int32

}

// Reads a pyc file

func ReadPyc(r io.Reader) (obj py.Object, err error) {

var header PycHeader

if err = binary.Read(r, binary.LittleEndian, &header); err != nil {

return

}

// FIXME do something with timestamp & length?

if header.Magic>>16 != 0x0a0d {

return nil, errors.New("bad magic in .pyc file")

}

// fmt.Printf("header = %v\n", header)

return ReadObject(r)

}

const dump_doc = `dump(value, file[, version])

Write the value on the open file. The value must be a supported type.

The file must be an open file object such as sys.stdout or returned by

open() or os.popen(). It must be opened in binary mode ('wb' or 'w+b').

If the value has (or contains an object that has) an unsupported type, a

ValueError exception is raised — but garbage data will also be written

to the file. The object will not be properly read back by load()

The version argument indicates the data format that dump should use.`

func marshal_dump(self py.Object, args py.Tuple) (py.Object, error) {

// XXX Quick hack -- need to do this differently

PyObject *x;

PyObject *f;

int version = Py_MARSHAL_VERSION;

PyObject *s;

PyObject *res;

_Py_IDENTIFIER(write);

if (!PyArg_ParseTuple(args, "OO|i:dump", &x, &f, &version))

return NULL;

s = PyMarshal_WriteObjectToString(x, version);

if (s == NULL)

return NULL;

res = _PyObject_CallMethodId(f, &PyId_write, "O", s);

Py_DECREF(s);

return res;

return nil, py.ExceptionNewf(py.SystemError, "dump not implemented")

}

const load_doc = `load(file)

Read one value from the open file and return it. If no valid value is

read (e.g. because the data has a different Python version’s

incompatible marshal format), raise EOFError, ValueError or TypeError.

The file must be an open file object opened in binary mode ('rb' or

'r+b').

Note: If an object containing an unsupported type was marshalled with

dump(), load() will substitute None for the unmarshallable type.`

func marshal_load(self, f py.Object) (py.Object, error) {

PyObject *data, *result;

_Py_IDENTIFIER(read);

RFILE rf;

// Make a call to the read method, but read zero bytes.

// This is to ensure that the object passed in at least

// has a read method which returns bytes.

data = _PyObject_CallMethodId(f, &PyId_read, "i", 0);

if (data == NULL)

return NULL;

if (!PyBytes_Check(data)) {

PyErr_Format(PyExc_TypeError,

"f.read() returned not bytes but %.100s",

data->ob_type->tp_name);

result = NULL;

}

else {

rf.depth = 0;

rf.fp = NULL;

rf.readable = f;

rf.current_filename = NULL;

result = read_object(&rf);

}

Py_DECREF(data);

return result;

return nil, py.ExceptionNewf(py.SystemError, "load not implemented")

}

const dumps_doc = `dumps(value[, version])

Return the string that would be written to a file by dump(value, file).

The value must be a supported type. Raise a ValueError exception if

value has (or contains an object that has) an unsupported type.

The version argument indicates the data format that dumps should use.`

func marshal_dumps(self py.Object, args py.Tuple) (py.Object, error) {

PyObject *x;

int version = Py_MARSHAL_VERSION;

if (!PyArg_ParseTuple(args, "O|i:dumps", &x, &version))

return NULL;

return PyMarshal_WriteObjectToString(x, version);

return nil, py.ExceptionNewf(py.SystemError, "dumps not implemented")

}

const loads_doc = `loads(bytes)

Convert the bytes object to a value. If no valid value is found, raise

EOFError, ValueError or TypeError. Extra characters in the input are

ignored.`

func marshal_loads(self py.Object, args py.Tuple) (py.Object, error) {

RFILE rf;

Py_buffer p;

char *s;

Py_ssize_t n;

PyObject* result;

if (!PyArg_ParseTuple(args, "y*:loads", &p))

return NULL;

s = p.buf;

n = p.len;

rf.fp = NULL;

rf.readable = NULL;

rf.current_filename = NULL;

rf.ptr = s;

rf.end = s + n;

rf.depth = 0;

result = read_object(&rf);

PyBuffer_Release(&p);

return result;

return nil, py.ExceptionNewf(py.SystemError, "loads not implemented")

}

const module_doc = `This module contains functions that can read and write Python values in

a binary format. The format is specific to Python, but independent of

machine architecture issues.

Not all Python object types are supported; in general, only objects

whose value is independent from a particular invocation of Python can be

written and read by this module. The following types are supported:

None, integers, floating point numbers, strings, bytes, bytearrays,

tuples, lists, sets, dictionaries, and code objects, where it

should be understood that tuples, lists and dictionaries are only

supported as long as the values contained therein are themselves

supported; and recursive lists and dictionaries should not be written

(they will cause infinite loops).

Variables:

version -- indicates the format that the module uses. Version 0 is the

historical format, version 1 shares interned strings and version 2

uses a binary format for floating point numbers.

Functions:

dump() -- write value to a file

load() -- read value from a file

dumps() -- write value to a string

loads() -- read value from a string`

// Initialise the module

func init() {

methods := []*py.Method{

py.MustNewMethod("dump", marshal_dump, 0, dump_doc),

py.MustNewMethod("load", marshal_load, 0, load_doc),

py.MustNewMethod("dumps", marshal_dumps, 0, dumps_doc),

py.MustNewMethod("loads", marshal_loads, 0, loads_doc),

}

globals := py.StringDict{

"version": py.Int(MARSHAL_VERSION),

}

py.RegisterModule(&py.ModuleImpl{

Info: py.ModuleInfo{

Name: "marshal",

Doc: module_doc,

Flags: py.ShareModule,

Globals: globals,

Methods: methods,

})

}

gpython/stdlib/marshal/marshal.go at main · go-python/gpython · GitHub

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