marshal.c

python s60 1.4.5版本的源代码

/* Portions Copyright (c) 2005 Nokia Corporation */

/* Write Python objects to files and read them back.
   This is intended for writing and reading compiled Python code only;
   a true persistent storage facility would be much harder, since
   it would have to take circular links and sharing into account. */

#include "Python.h"
#include "longintrepr.h"
#include "compile.h"
#include "marshal.h"

/* High water mark to determine when the marshalled object is dangerously deep
 * and risks coring the interpreter.  When the object stack gets this deep,
 * raise an exception instead of continuing.
 */
#define MAX_MARSHAL_STACK_DEPTH 5000

#define TYPE_NULL	'0'
#define TYPE_NONE	'N'
#define TYPE_STOPITER	'S'
#define TYPE_ELLIPSIS   '.'
#define TYPE_INT	'i'
#define TYPE_INT64	'I'
#define TYPE_FLOAT	'f'
#define TYPE_COMPLEX	'x'
#define TYPE_LONG	'l'
#define TYPE_STRING	's'
#define TYPE_TUPLE	'('
#define TYPE_LIST	'['
#define TYPE_DICT	'{'
#define TYPE_CODE	'c'
#define TYPE_UNICODE	'u'
#define TYPE_UNKNOWN	'?'

typedef struct {
	FILE *fp;
	int error;
	int depth;
	/* If fp == NULL, the following are valid: */
	PyObject *str;
	char *ptr;
	char *end;
} WFILE;

#define w_byte(c, p) if (((p)->fp)) putc((c), (p)->fp); \
		      else if ((p)->ptr != (p)->end) *(p)->ptr++ = (c); \
			   else w_more(c, p)

static void
w_more(int c, WFILE *p)
{
	int size, newsize;
	if (p->str == NULL)
		return; /* An error already occurred */
	size = PyString_Size(p->str);
	newsize = size + 1024;
	if (_PyString_Resize(&p->str, newsize) != 0) {
		p->ptr = p->end = NULL;
	}
	else {
		p->ptr = PyString_AS_STRING((PyStringObject *)p->str) + size;
		p->end =
			PyString_AS_STRING((PyStringObject *)p->str) + newsize;
		*p->ptr++ = Py_SAFE_DOWNCAST(c, int, char);
	}
}

static void
w_string(char *s, int n, WFILE *p)
{
	if (p->fp != NULL) {
		fwrite(s, 1, n, p->fp);
	}
	else {
		while (--n >= 0) {
			w_byte(*s, p);
			s++;
		}
	}
}

static void
w_short(int x, WFILE *p)
{
	w_byte((char)( x      & 0xff), p);
	w_byte((char)((x>> 8) & 0xff), p);
}

static void
w_long(long x, WFILE *p)
{
	w_byte((char)( x      & 0xff), p);
	w_byte((char)((x>> 8) & 0xff), p);
	w_byte((char)((x>>16) & 0xff), p);
	w_byte((char)((x>>24) & 0xff), p);
}

#if SIZEOF_LONG > 4
static void
w_long64(long x, WFILE *p)
{
	w_long(x, p);
	w_long(x>>32, p);
}
#endif

static void
w_object(PyObject *v, WFILE *p)
{
	int i, n;

	p->depth++;

	if (p->depth > MAX_MARSHAL_STACK_DEPTH) {
		p->error = 2;
	}
	else if (v == NULL) {
		w_byte(TYPE_NULL, p);
	}
	else if (v == Py_None) {
		w_byte(TYPE_NONE, p);
	}
	else if (v == PyExc_StopIteration) {
		w_byte(TYPE_STOPITER, p);
	}
	else if (v == Py_Ellipsis) {
	        w_byte(TYPE_ELLIPSIS, p);
	}
	else if (PyInt_Check(v)) {
		long x = PyInt_AS_LONG((PyIntObject *)v);
#if SIZEOF_LONG > 4
		long y = Py_ARITHMETIC_RIGHT_SHIFT(long, x, 31);
		if (y && y != -1) {
			w_byte(TYPE_INT64, p);
			w_long64(x, p);
		}
		else
#endif
			{
			w_byte(TYPE_INT, p);
			w_long(x, p);
		}
	}
	else if (PyLong_Check(v)) {
		PyLongObject *ob = (PyLongObject *)v;
		w_byte(TYPE_LONG, p);
		n = ob->ob_size;
		w_long((long)n, p);
		if (n < 0)
			n = -n;
		for (i = 0; i < n; i++)
			w_short(ob->ob_digit[i], p);
	}
	else if (PyFloat_Check(v)) {
		char buf[256]; /* Plenty to format any double */
		PyFloat_AsReprString(buf, (PyFloatObject *)v);
		n = strlen(buf);
		w_byte(TYPE_FLOAT, p);
		w_byte(n, p);
		w_string(buf, n, p);
	}
#ifndef WITHOUT_COMPLEX
	else if (PyComplex_Check(v)) {
		char buf[256]; /* Plenty to format any double */
		PyFloatObject *temp;
		w_byte(TYPE_COMPLEX, p);
		temp = (PyFloatObject*)PyFloat_FromDouble(
			PyComplex_RealAsDouble(v));
		PyFloat_AsReprString(buf, temp);
		Py_DECREF(temp);
		n = strlen(buf);
		w_byte(n, p);
		w_string(buf, n, p);
		temp = (PyFloatObject*)PyFloat_FromDouble(
			PyComplex_ImagAsDouble(v));
		PyFloat_AsReprString(buf, temp);
		Py_DECREF(temp);
		n = strlen(buf);
		w_byte(n, p);
		w_string(buf, n, p);
	}
#endif
	else if (PyString_Check(v)) {
		w_byte(TYPE_STRING, p);
		n = PyString_GET_SIZE(v);
		w_long((long)n, p);
		w_string(PyString_AS_STRING(v), n, p);
	}
#ifdef Py_USING_UNICODE
	else if (PyUnicode_Check(v)) {
	        PyObject *utf8;
		utf8 = PyUnicode_AsUTF8String(v);
		if (utf8 == NULL) {
			p->depth--;
			p->error = 1;
			return;
		}
		w_byte(TYPE_UNICODE, p);
		n = PyString_GET_SIZE(utf8);
		w_long((long)n, p);
		w_string(PyString_AS_STRING(utf8), n, p);
		Py_DECREF(utf8);
	}
#endif
	else if (PyTuple_Check(v)) {
		w_byte(TYPE_TUPLE, p);
		n = PyTuple_Size(v);
		w_long((long)n, p);
		for (i = 0; i < n; i++) {
			w_object(PyTuple_GET_ITEM(v, i), p);
		}
	}
	else if (PyList_Check(v)) {
		w_byte(TYPE_LIST, p);
		n = PyList_GET_SIZE(v);
		w_long((long)n, p);
		for (i = 0; i < n; i++) {
			w_object(PyList_GET_ITEM(v, i), p);
		}
	}
	else if (PyDict_Check(v)) {
		int pos;
		PyObject *key, *value;
		w_byte(TYPE_DICT, p);
		/* This one is NULL object terminated! */
		pos = 0;
		while (PyDict_Next(v, &pos, &key, &value)) {
			w_object(key, p);
			w_object(value, p);
		}
		w_object((PyObject *)NULL, p);
	}
	else if (PyCode_Check(v)) {
		PyCodeObject *co = (PyCodeObject *)v;
		w_byte(TYPE_CODE, p);
		w_short(co->co_argcount, p);
		w_short(co->co_nlocals, p);
		w_short(co->co_stacksize, p);
		w_short(co->co_flags, p);
		w_object(co->co_code, p);
		w_object(co->co_consts, p);
		w_object(co->co_names, p);
		w_object(co->co_varnames, p);
		w_object(co->co_freevars, p);
		w_object(co->co_cellvars, p);
		w_object(co->co_filename, p);
		w_object(co->co_name, p);
		w_short(co->co_firstlineno, p);
		w_object(co->co_lnotab, p);
	}
	else if (PyObject_CheckReadBuffer(v)) {
		/* Write unknown buffer-style objects as a string */
		char *s;
		// XXX:CW32
		PyBufferProcs *pb = (PyBufferProcs *)v->ob_type->tp_as_buffer;
		w_byte(TYPE_STRING, p);
		n = (*pb->bf_getreadbuffer)(v, 0, (void **)&s);
		w_long((long)n, p);
		w_string(s, n, p);
	}
	else {
		w_byte(TYPE_UNKNOWN, p);
		p->error = 1;
	}

	p->depth--;
}

DL_EXPORT(void)
PyMarshal_WriteLongToFile(long x, FILE *fp)
{
	WFILE wf;
	wf.fp = fp;
	wf.error = 0;
	wf.depth = 0;
	w_long(x, &wf);
}

DL_EXPORT(void)
PyMarshal_WriteObjectToFile(PyObject *x, FILE *fp)
{
	WFILE wf;
	wf.fp = fp;
	wf.error = 0;
	wf.depth = 0;
	w_object(x, &wf);
}

typedef WFILE RFILE; /* Same struct with different invariants */

#define rs_byte(p) (((p)->ptr != (p)->end) ? (unsigned char)*(p)->ptr++ : EOF)

#define r_byte(p) ((p)->fp ? getc((p)->fp) : rs_byte(p))

static int
r_string(char *s, int n, RFILE *p)
{
	if (p->fp != NULL)
		return fread(s, 1, n, p->fp);
	if (p->end - p->ptr < n)
		n = p->end - p->ptr;
	memcpy(s, p->ptr, n);
	p->ptr += n;
	return n;
}

static int
r_short(RFILE *p)
{
	register short x;
	x = r_byte(p);
	x |= r_byte(p) << 8;
	/* Sign-extension, in case short greater than 16 bits */
	x |= -(x & 0x8000);
	return x;
}

static long
r_long(RFILE *p)
{
	register long x;
	register FILE *fp = p->fp;
	if (fp) {
		x = getc(fp);
		x |= (long)getc(fp) << 8;
		x |= (long)getc(fp) << 16;
		x |= (long)getc(fp) << 24;
	}
	else {
		x = rs_byte(p);
		x |= (long)rs_byte(p) << 8;
		x |= (long)rs_byte(p) << 16;
		x |= (long)rs_byte(p) << 24;
	}
#if SIZEOF_LONG > 4
	/* Sign extension for 64-bit machines */
	x |= -(x & 0x80000000L);
#endif
	return x;
}

/* r_long64 deals with the TYPE_INT64 code.  On a machine with
   sizeof(long) > 4, it returns a Python int object, else a Python long
   object.  Note that w_long64 writes out TYPE_INT if 32 bits is enough,
   so there's no inefficiency here in returning a PyLong on 32-bit boxes
   for everything written via TYPE_INT64 (i.e., if an int is written via
   TYPE_INT64, it *needs* more than 32 bits).
*/
static PyObject *
r_long64(RFILE *p)
{
	long lo4 = r_long(p);
	long hi4 = r_long(p);
#if SIZEOF_LONG > 4
	long x = (hi4 << 32) | (lo4 & 0xFFFFFFFFL);
	return PyInt_FromLong(x);
#else
	unsigned char buf[8];
	int one = 1;
	int is_little_endian = (int)*(char*)&one;
	if (is_little_endian) {
		memcpy(buf, &lo4, 4);
		memcpy(buf+4, &hi4, 4);
	}
	else {
		memcpy(buf, &hi4, 4);
		memcpy(buf+4, &lo4, 4);
	}
	return _PyLong_FromByteArray(buf, 8, is_little_endian, 1);
#endif
}

static PyObject *
r_object(RFILE *p)
{
	PyObject *v, *v2;
	long i, n;
	int type = r_byte(p);

	switch (type) {

	case EOF:
		PyErr_SetString(PyExc_EOFError,
				"EOF read where object expected");
		return NULL;

	case TYPE_NULL:
		return NULL;

	case TYPE_NONE:
		Py_INCREF(Py_None);
		return Py_None;

	case TYPE_STOPITER:
		Py_INCREF(PyExc_StopIteration);
		return PyExc_StopIteration;

	case TYPE_ELLIPSIS:
		Py_INCREF(Py_Ellipsis);
		return Py_Ellipsis;

	case TYPE_INT:
		return PyInt_FromLong(r_long(p));

	case TYPE_INT64:
		return r_long64(p);

	case TYPE_LONG:
		{
			int size;
			PyLongObject *ob;
			n = r_long(p);
			size = n<0 ? -n : n;
			ob = _PyLong_New(size);
			if (ob == NULL)
				return NULL;
			ob->ob_size = n;
			for (i = 0; i < size; i++)
				ob->ob_digit[i] = r_short(p);
			return (PyObject *)ob;
		}

	case TYPE_FLOAT:
		{
			char buf[256];
			double dx;
			n = r_byte(p);
			if (r_string(buf, (int)n, p) != n) {
				PyErr_SetString(PyExc_EOFError,
					"EOF read where object expected");
				return NULL;
			}
			buf[n] = '\0';
			PyFPE_START_PROTECT("atof", return 0)
			dx = atof(buf);
			PyFPE_END_PROTECT(dx)