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SF bug #422177: Results from .pyc differs from .py 

Store floats and doubles to full precision in marshal.
Test that floats read from .pyc/.pyo closely match those read from .py.
Declare PyFloat_AsString() in floatobject header file.
Add new PyFloat_AsReprString() API function.
Document the functions declared in floatobject.h.
This commit is contained in:
Tim Peters 2001-05-08 15:19:57 +00:00
parent 569c09c013
commit 72f98e9b83
4 changed files with 35 additions and 9 deletions
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27
Include/floatobject.h
View File

@ -20,13 +20,32 @@ extern DL_IMPORT(PyTypeObject) PyFloat_Type;
#define PyFloat_Check(op) ((op)->ob_type == &PyFloat_Type)
extern DL_IMPORT(PyObject *) PyFloat_FromString(PyObject*, char**);
extern DL_IMPORT(PyObject *) PyFloat_FromDouble(double);
extern DL_IMPORT(double) PyFloat_AsDouble(PyObject *);
/* Return Python float from string PyObject. Second argument ignored on
input, and, if non-NULL, NULL is stored into *junk (this tried to serve a
purpose once but can't be made to work as intended). */
extern DL_IMPORT(PyObject *) PyFloat_FromString(PyObject*, char** junk);
/* Macro, trading safety for speed */
/* Return Python float from C double. */
extern DL_IMPORT(PyObject *) PyFloat_FromDouble(double);
/* Extract C double from Python float. The macro version trades safety for
speed. */
extern DL_IMPORT(double) PyFloat_AsDouble(PyObject *);
#define PyFloat_AS_DOUBLE(op) (((PyFloatObject *)(op))->ob_fval)
/* Write repr(v) into the char buffer argument, followed by null byte. The
buffer must be "big enough"; >= 100 is very safe.
PyFloat_AsReprString(buf, x) strives to print enough digits so that
PyFloat_FromString(buf) then reproduces x exactly. */
extern DL_IMPORT(void) PyFloat_AsReprString(char*, PyFloatObject *v);
/* Write str(v) into the char buffer argument, followed by null byte. The
buffer must be "big enough"; >= 100 is very safe. Note that it's
unusual to be able to get back the float you started with from
PyFloat_AsString's result -- use PyFloat_AsReprString() if you want to
preserve precision across conversions. */
extern DL_IMPORT(void) PyFloat_AsString(char*, PyFloatObject *v);
#ifdef __cplusplus
}
#endif

3
Lib/test/test_import.py
View File

@ -13,6 +13,9 @@ except ImportError:
else:
raise TestFailed("import of RAnDoM should have failed (case mismatch)")
# Another brief digression to test the accuracy of manifest float constants.
import double_const # don't blink -- that *was* the test
sys.path.insert(0, os.curdir)
source = TESTFN + ".py"

6
Objects/floatobject.c
View File

@ -311,6 +311,12 @@ PyFloat_AsString(char *buf, PyFloatObject *v)
PyFloat_AsStringEx(buf, v, PREC_STR);
}
void
PyFloat_AsReprString(char *buf, PyFloatObject *v)
{
PyFloat_AsStringEx(buf, v, PREC_REPR);
}
/* ARGSUSED */
static int
float_print(PyFloatObject *v, FILE *fp, int flags)

8
Python/marshal.c
View File

@ -149,9 +149,8 @@ w_object(PyObject *v, WFILE *p)
w_short(ob->ob_digit[i], p);
}
else if (PyFloat_Check(v)) {
extern void PyFloat_AsString(char *, PyFloatObject *);
char buf[256]; /* Plenty to format any double */
PyFloat_AsString(buf, (PyFloatObject *)v);
PyFloat_AsReprString(buf, (PyFloatObject *)v);
n = strlen(buf);
w_byte(TYPE_FLOAT, p);
w_byte(n, p);
@ -159,20 +158,19 @@ w_object(PyObject *v, WFILE *p)
}
#ifndef WITHOUT_COMPLEX
else if (PyComplex_Check(v)) {
extern void PyFloat_AsString(char *, PyFloatObject *);
char buf[256]; /* Plenty to format any double */
PyFloatObject *temp;
w_byte(TYPE_COMPLEX, p);
temp = (PyFloatObject*)PyFloat_FromDouble(
PyComplex_RealAsDouble(v));
PyFloat_AsString(buf, temp);
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_AsString(buf, temp);
PyFloat_AsReprString(buf, temp);
Py_DECREF(temp);
n = strlen(buf);
w_byte(n, p);