Merge issue #26355 fix from Python 3.5

1 files changed, 108 insertions, 5 deletions

diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
index e15941aec8..fcc1f151cf 100644
--- a/Modules/_decimal/_decimal.c
+++ b/Modules/_decimal/_decimal.c
@@ -36,7 +36,6 @@
 #include <stdlib.h>
 
 #include "docstrings.h"
-#include "memory.h"
 
 
 #if !defined(MPD_VERSION_HEX) || MPD_VERSION_HEX < 0x02040100
@@ -1890,12 +1889,13 @@ is_space(enum PyUnicode_Kind kind, void *data, Py_ssize_t pos)
 /* Return the ASCII representation of a numeric Unicode string. The numeric
    string may contain ascii characters in the range [1, 127], any Unicode
    space and any unicode digit. If strip_ws is true, leading and trailing
-   whitespace is stripped.
+   whitespace is stripped. If ignore_underscores is true, underscores are
+   ignored.
 
    Return NULL if malloc fails and an empty string if invalid characters
    are found. */
 static char *
-numeric_as_ascii(const PyObject *u, int strip_ws)
+numeric_as_ascii(const PyObject *u, int strip_ws, int ignore_underscores)
 {
     enum PyUnicode_Kind kind;
     void *data;
@@ -1930,6 +1930,9 @@ numeric_as_ascii(const PyObject *u, int strip_ws)
 
     for (; j < len; j++) {
         ch = PyUnicode_READ(kind, data, j);
+        if (ignore_underscores && ch == '_') {
+            continue;
+        }
         if (0 < ch && ch <= 127) {
             *cp++ = ch;
             continue;
@@ -2012,7 +2015,7 @@ PyDecType_FromUnicode(PyTypeObject *type, const PyObject *u,
     PyObject *dec;
     char *s;
 
-    s = numeric_as_ascii(u, 0);
+    s = numeric_as_ascii(u, 0, 0);
     if (s == NULL) {
         return NULL;
     }
@@ -2032,7 +2035,7 @@ PyDecType_FromUnicodeExactWS(PyTypeObject *type, const PyObject *u,
     PyObject *dec;
     char *s;
 
-    s = numeric_as_ascii(u, 1);
+    s = numeric_as_ascii(u, 1, 1);
     if (s == NULL) {
         return NULL;
     }
@@ -3394,6 +3397,105 @@ dec_as_long(PyObject *dec, PyObject *context, int round)
     return (PyObject *) pylong;
 }
 
+/* Convert a Decimal to its exact integer ratio representation. */
+static PyObject *
+dec_as_integer_ratio(PyObject *self, PyObject *args UNUSED)
+{
+    PyObject *numerator = NULL;
+    PyObject *denominator = NULL;
+    PyObject *exponent = NULL;
+    PyObject *result = NULL;
+    PyObject *tmp;
+    mpd_ssize_t exp;
+    PyObject *context;
+    uint32_t status = 0;
+
+    if (mpd_isspecial(MPD(self))) {
+        if (mpd_isnan(MPD(self))) {
+            PyErr_SetString(PyExc_ValueError,
+                "cannot convert NaN to integer ratio");
+        }
+        else {
+            PyErr_SetString(PyExc_OverflowError,
+                "cannot convert Infinity to integer ratio");
+        }
+        return NULL;
+    }
+
+    CURRENT_CONTEXT(context);
+
+    tmp = dec_alloc();
+    if (tmp == NULL) {
+        return NULL;
+    }
+
+    if (!mpd_qcopy(MPD(tmp), MPD(self), &status)) {
+        Py_DECREF(tmp);
+        PyErr_NoMemory();
+        return NULL;
+    }
+
+    exp = mpd_iszero(MPD(tmp)) ? 0 : MPD(tmp)->exp;
+    MPD(tmp)->exp = 0;
+
+    /* context and rounding are unused here: the conversion is exact */
+    numerator = dec_as_long(tmp, context, MPD_ROUND_FLOOR);
+    Py_DECREF(tmp);
+    if (numerator == NULL) {
+        goto error;
+    }
+
+    exponent = PyLong_FromSsize_t(exp < 0 ? -exp : exp);
+    if (exponent == NULL) {
+        goto error;
+    }
+
+    tmp = PyLong_FromLong(10);
+    if (tmp == NULL) {
+        goto error;
+    }
+
+    Py_SETREF(exponent, _py_long_power(tmp, exponent, Py_None));
+    Py_DECREF(tmp);
+    if (exponent == NULL) {
+        goto error;
+    }
+
+    if (exp >= 0) {
+        Py_SETREF(numerator, _py_long_multiply(numerator, exponent));
+        if (numerator == NULL) {
+            goto error;
+        }
+        denominator = PyLong_FromLong(1);
+        if (denominator == NULL) {
+            goto error;
+        }
+    }
+    else {
+        denominator = exponent;
+        exponent = NULL;
+        tmp = _PyLong_GCD(numerator, denominator);
+        if (tmp == NULL) {
+            goto error;
+        }
+        Py_SETREF(numerator, _py_long_floor_divide(numerator, tmp));
+        Py_SETREF(denominator, _py_long_floor_divide(denominator, tmp));
+        Py_DECREF(tmp);
+        if (numerator == NULL || denominator == NULL) {
+            goto error;
+        }
+    }
+
+    result = PyTuple_Pack(2, numerator, denominator);
+
+
+error:
+    Py_XDECREF(exponent);
+    Py_XDECREF(denominator);
+    Py_XDECREF(numerator);
+    return result;
+}
+
 static PyObject *
 PyDec_ToIntegralValue(PyObject *dec, PyObject *args, PyObject *kwds)
 {
@@ -4702,6 +4804,7 @@ static PyMethodDef dec_methods [] =
   /* Miscellaneous */
   { "from_float", dec_from_float, METH_O|METH_CLASS, doc_from_float },
   { "as_tuple", PyDec_AsTuple, METH_NOARGS, doc_as_tuple },
+  { "as_integer_ratio", dec_as_integer_ratio, METH_NOARGS, doc_as_integer_ratio },
 
   /* Special methods */
   { "__copy__", dec_copy, METH_NOARGS, NULL },