floatobject.c

python s60 1.4.5版本的源代码

/* Portions Copyright (c) 2005-2007 Nokia Corporation */

/* Float object implementation */

/* XXX There should be overflow checks here, but it's hard to check
   for any kind of float exception without losing portability. */

#include "Python.h"

#include <ctype.h>

#if !defined(__STDC__) && !defined(macintosh)
extern double fmod(double, double);
extern double pow(double, double);
#endif

#if defined(sun) && !defined(__SVR4)
/* On SunOS4.1 only libm.a exists. Make sure that references to all
   needed math functions exist in the executable, so that dynamic
   loading of mathmodule does not fail. */
double (*_Py_math_funcs_hack[])() = {
	acos, asin, atan, atan2, ceil, cos, cosh, exp, fabs, floor,
	fmod, log, log10, pow, sin, sinh, sqrt, tan, tanh
};
#endif

/* Special free list -- see comments for same code in intobject.c. */

#define BLOCK_SIZE	1000	// 1K less typical malloc overhead
#define BHEAD_SIZE	8	// Enough for a 64-bit pointer
#define N_FLOATOBJECTS	((BLOCK_SIZE - BHEAD_SIZE) / sizeof(PyFloatObject))

struct _floatblock {
	struct _floatblock *next;
	PyFloatObject objects[N_FLOATOBJECTS];
};

typedef struct _floatblock PyFloatBlock;

#ifndef SYMBIAN
static PyFloatBlock *block_list = NULL;
static PyFloatObject *free_list = NULL;
#else
#define block_list ((PyFloatBlock*)(pyglobals->block_list))
#define free_list ((PyFloatObject*)(pyglobals->free_list))
#endif

static PyFloatObject *
fill_free_list(void)
{
	PyFloatObject *p, *q;
#ifdef SYMBIAN
	SPy_Python_globals* pyglobals = PYTHON_GLOBALS; // avoid TLS reads
#endif
	/* XXX Float blocks escape the object heap. Use PyObject_MALLOC ??? */
	p = (PyFloatObject *) PyMem_MALLOC(sizeof(PyFloatBlock));
	if (p == NULL)
		return (PyFloatObject *) PyErr_NoMemory();
	((PyFloatBlock *)p)->next = block_list;
	block_list = (PyFloatBlock *)p;
	p = &((PyFloatBlock *)p)->objects[0];
	q = p + N_FLOATOBJECTS;
	while (--q > p)
		q->ob_type = (struct _typeobject *)(q-1);
	q->ob_type = NULL;
	return p + N_FLOATOBJECTS - 1;
}

DL_EXPORT(PyObject *)
PyFloat_FromDouble(double fval)
{
	register PyFloatObject *op;
#ifdef SYMBIAN
	SPy_Python_globals* pyglobals = PYTHON_GLOBALS; // avoid TLS reads
#endif
	if (free_list == NULL) {
		if ((free_list = fill_free_list()) == NULL)
			return NULL;
	}
	/* PyObject_New is inlined */
	op = free_list;
	free_list = (PyFloatObject *)op->ob_type;
	PyObject_INIT(op, &PyFloat_Type);
	op->ob_fval = fval;
	return (PyObject *) op;
}

/**************************************************************************
RED_FLAG 22-Sep-2000 tim
PyFloat_FromString's pend argument is braindead.  Prior to this RED_FLAG,

1.  If v was a regular string, *pend was set to point to its terminating
    null byte.  That's useless (the caller can find that without any
    help from this function!).

2.  If v was a Unicode string, or an object convertible to a character
    buffer, *pend was set to point into stack trash (the auto temp
    vector holding the character buffer).  That was downright dangerous.

Since we can't change the interface of a public API function, pend is
still supported but now *officially* useless:  if pend is not NULL,
*pend is set to NULL.
**************************************************************************/
DL_EXPORT(PyObject *)
PyFloat_FromString(PyObject *v, char **pend)
{
	const char *s, *last, *end;
	double x;
	char buffer[256]; /* for errors */
#ifdef Py_USING_UNICODE
	char s_buffer[256]; /* for objects convertible to a char buffer */
#endif
	int len;

	if (pend)
		*pend = NULL;
	if (PyString_Check(v)) {
		s = PyString_AS_STRING(v);
		len = PyString_GET_SIZE(v);
	}
#ifdef Py_USING_UNICODE
	else if (PyUnicode_Check(v)) {
		if (PyUnicode_GET_SIZE(v) >= sizeof(s_buffer)) {
			PyErr_SetString(PyExc_ValueError,
				"Unicode float() literal too long to convert");
			return NULL;
		}
		if (PyUnicode_EncodeDecimal(PyUnicode_AS_UNICODE(v),
					    PyUnicode_GET_SIZE(v),
					    s_buffer,
					    NULL))
			return NULL;
		s = s_buffer;
		len = (int)strlen(s);
	}
#endif
	else if (PyObject_AsCharBuffer(v, &s, &len)) {
		PyErr_SetString(PyExc_TypeError,
				"float() argument must be a string or a number");
		return NULL;
	}

	last = s + len;
	while (*s && isspace(Py_CHARMASK(*s)))
		s++;
	if (*s == '\0') {
		PyErr_SetString(PyExc_ValueError, "empty string for float()");
		return NULL;
	}
	/* We don't care about overflow or underflow.  If the platform supports
	 * them, infinities and signed zeroes (on underflow) are fine.
	 * However, strtod can return 0 for denormalized numbers, where atof
	 * does not.  So (alas!) we special-case a zero result.  Note that
	 * whether strtod sets errno on underflow is not defined, so we can't
	 * key off errno.
         */
	PyFPE_START_PROTECT("strtod", return NULL)
	x = strtod(s, (char **)&end);
	PyFPE_END_PROTECT(x)
	errno = 0;
	/* Believe it or not, Solaris 2.6 can move end *beyond* the null
	   byte at the end of the string, when the input is inf(inity). */
	if (end > last)
		end = last;
	if (end == s) {
		PyOS_snprintf(buffer, sizeof(buffer),
			      "invalid literal for float(): %.200s", s);
		PyErr_SetString(PyExc_ValueError, buffer);
		return NULL;
	}
	/* Since end != s, the platform made *some* kind of sense out
	   of the input.  Trust it. */
	while (*end && isspace(Py_CHARMASK(*end)))
		end++;
	if (*end != '\0') {
		PyOS_snprintf(buffer, sizeof(buffer),
			      "invalid literal for float(): %.200s", s);
		PyErr_SetString(PyExc_ValueError, buffer);
		return NULL;
	}
	else if (end != last) {
		PyErr_SetString(PyExc_ValueError,
				"null byte in argument for float()");
		return NULL;
	}
	if (x == 0.0) {
		/* See above -- may have been strtod being anal
		   about denorms. */
		PyFPE_START_PROTECT("atof", return NULL)
		x = atof(s);
		PyFPE_END_PROTECT(x)
		errno = 0;    /* whether atof ever set errno is undefined */
	}
	return PyFloat_FromDouble(x);
}

static void
float_dealloc(PyFloatObject *op)
{
#ifdef SYMBIAN
	SPy_Python_globals* pyglobals = PYTHON_GLOBALS; // avoid TLS reads
#endif
	if (PyFloat_CheckExact(op)) {
		op->ob_type = (struct _typeobject *)free_list;
		free_list = op;
	}
	else
		op->ob_type->tp_free((PyObject *)op);
}

DL_EXPORT(double)
PyFloat_AsDouble(PyObject *op)
{
	PyNumberMethods *nb;
	PyFloatObject *fo;
	double val;

	if (op && PyFloat_Check(op))
		return PyFloat_AS_DOUBLE((PyFloatObject*) op);
	
  	// XXX:CW32
	if (op == NULL || (nb = (PyNumberMethods *)op->ob_type->tp_as_number) == NULL ||
	    nb->nb_float == NULL) {
		PyErr_BadArgument();
		return -1;
	}

	fo = (PyFloatObject*) (*nb->nb_float) (op);
	if (fo == NULL)
		return -1;
	if (!PyFloat_Check(fo)) {
		PyErr_SetString(PyExc_TypeError,
				"nb_float should return float object");
		return -1;
	}

	val = PyFloat_AS_DOUBLE(fo);
	Py_DECREF(fo);

	return val;
}

/* Methods */

static void
format_float(char *buf, size_t buflen, PyFloatObject *v, int precision)
{
	register char *cp;
#ifdef EKA2
	char *pchar;
#endif
	/* Subroutine for float_repr and float_print.
	   We want float numbers to be recognizable as such,
	   i.e., they should contain a decimal point or an exponent.
	   However, %g may print the number as an integer;
	   in such cases, we append ".0" to the string. */

	assert(PyFloat_Check(v));
	PyOS_snprintf(buf, buflen, "%.*g", precision, v->ob_fval);
#ifdef EKA2
	pchar = (char*) memchr (buf, ',', strlen(buf));
	if (pchar!=NULL) 
		*pchar = '.';
#endif
	cp = buf;
	if (*cp == '-')
		cp++;
	for (; *cp != '\0'; cp++) {
		/* Any non-digit means it's not an integer;
		   this takes care of NAN and INF as well. */
		if (!isdigit(Py_CHARMASK(*cp)))
			break;
	}
	if (*cp == '\0') {
		*cp++ = '.';
		*cp++ = '0';
		*cp++ = '\0';
	}
}

/* XXX PyFloat_AsStringEx should not be a public API function (for one
   XXX thing, its signature passes a buffer without a length; for another,
   XXX it isn't useful outside this file).
*/
DL_EXPORT(void)
PyFloat_AsStringEx(char *buf, PyFloatObject *v, int precision)
{
	format_float(buf, 100, v, precision);
}

/* Macro and helper that convert PyObject obj to a C double and store
   the value in dbl; this replaces the functionality of the coercion
   slot function.  If conversion to double raises an exception, obj is
   set to NULL, and the function invoking this macro returns NULL.  If
   obj is not of float, int or long type, Py_NotImplemented is incref'ed,
   stored in obj, and returned from the function invoking this macro.
*/
#define CONVERT_TO_DOUBLE(obj, dbl)			\
	if (PyFloat_Check(obj))				\
		dbl = PyFloat_AS_DOUBLE(obj);		\
	else if (convert_to_double(&(obj), &(dbl)) < 0)	\
		return obj;

static int
convert_to_double(PyObject **v, double *dbl)
{
	register PyObject *obj = *v;

	if (PyInt_Check(obj)) {
		*dbl = (double)PyInt_AS_LONG(obj);
	}
	else if (PyLong_Check(obj)) {
		*dbl = PyLong_AsDouble(obj);
		if (*dbl == -1.0 && PyErr_Occurred()) {
			*v = NULL;
			return -1;
		}
	}
	else {
		Py_INCREF(Py_NotImplemented);
		*v = Py_NotImplemented;
		return -1;
	}
	return 0;
}

/* Precisions used by repr() and str(), respectively.

   The repr() precision (17 significant decimal digits) is the minimal number
   that is guaranteed to have enough precision so that if the number is read
   back in the exact same binary value is recreated.  This is true for IEEE
   floating point by design, and also happens to work for all other modern
   hardware.

   The str() precision is chosen so that in most cases, the rounding noise
   created by various operations is suppressed, while giving plenty of
   precision for practical use.

*/

#define PREC_REPR	17
#define PREC_STR	12

/* XXX PyFloat_AsString and PyFloat_AsReprString should be deprecated:
   XXX they pass a char buffer without passing a length.
*/
DL_EXPORT(void)
PyFloat_AsString(char *buf, PyFloatObject *v)
{
	format_float(buf, 100, v, PREC_STR);
}

DL_EXPORT(void)
PyFloat_AsReprString(char *buf, PyFloatObject *v)
{
	format_float(buf, 100, v, PREC_REPR);
}

/* ARGSUSED */
static int
float_print(PyFloatObject *v, FILE *fp, int flags)
{
	char buf[100];
	format_float(buf, sizeof(buf), v,
		     (flags & Py_PRINT_RAW) ? PREC_STR : PREC_REPR);
	fputs(buf, fp);
	return 0;
}

static PyObject *
float_repr(PyFloatObject *v)
{
	char buf[100];
	format_float(buf, sizeof(buf), v, PREC_REPR);
	return PyString_FromString(buf);
}

static PyObject *
float_str(PyFloatObject *v)
{
	char buf[100];
	format_float(buf, sizeof(buf), v, PREC_STR);
	return PyString_FromString(buf);
}

static int
float_compare(PyFloatObject *v, PyFloatObject *w)
{
	double i = v->ob_fval;
	double j = w->ob_fval;
	return (i < j) ? -1 : (i > j) ? 1 : 0;
}

static long
float_hash(PyFloatObject *v)
{
	return _Py_HashDouble(v->ob_fval);
}

static PyObject *
float_add(PyObject *v, PyObject *w)
{
	double a,b;
	CONVERT_TO_DOUBLE(v, a);
	CONVERT_TO_DOUBLE(w, b);
	PyFPE_START_PROTECT("add", return 0)
	a = a + b;
	PyFPE_END_PROTECT(a)
	return PyFloat_FromDouble(a);
}

static PyObject *
float_sub(PyObject *v, PyObject *w)
{
	double a,b;
	CONVERT_TO_DOUBLE(v, a);
	CONVERT_TO_DOUBLE(w, b);
	PyFPE_START_PROTECT("subtract", return 0)
	a = a - b;
	PyFPE_END_PROTECT(a)
	return PyFloat_FromDouble(a);
}

static PyObject *
float_mul(PyObject *v, PyObject *w)
{
	double a,b;
	CONVERT_TO_DOUBLE(v, a);
	CONVERT_TO_DOUBLE(w, b);
	PyFPE_START_PROTECT("multiply", return 0)
	a = a * b;
	PyFPE_END_PROTECT(a)
	return PyFloat_FromDouble(a);
}

static PyObject *
float_div(PyObject *v, PyObject *w)
{
	double a,b;
	CONVERT_TO_DOUBLE(v, a);
	CONVERT_TO_DOUBLE(w, b);
	if (b == 0.0) {
		PyErr_SetString(PyExc_ZeroDivisionError, "float division");
		return NULL;
	}
	PyFPE_START_PROTECT("divide", return 0)
	a = a / b;
	PyFPE_END_PROTECT(a)
	return PyFloat_FromDouble(a);
}

static PyObject *
float_classic_div(PyObject *v, PyObject *w)
{
	double a,b;
	CONVERT_TO_DOUBLE(v, a);
	CONVERT_TO_DOUBLE(w, b);
	if (Py_DivisionWarningFlag >= 2 &&
	    PyErr_Warn(PyExc_DeprecationWarning, "classic float division") < 0)
	  return NULL;
	if (b == 0.0) {
		PyErr_SetString(PyExc_ZeroDivisionError, "float division");
		return NULL;
	}