Implement string-to-float conversion in Limited API (cythonGH-5695)

Cython/Utility/Optimize.c

@@ -688,7 +688,7 @@ static CYTHON_INLINE double __Pyx_PyUnicode_AsDouble(PyObject *obj);/*proto*/
 /////////////// pyunicode_as_double.proto ///////////////
 //@requires: pybytes_as_double
 
-#if PY_MAJOR_VERSION >= 3 && !CYTHON_COMPILING_IN_PYPY
+#if PY_MAJOR_VERSION >= 3 && !CYTHON_COMPILING_IN_PYPY && CYTHON_ASSUME_SAFE_MACROS
 static const char* __Pyx__PyUnicode_AsDouble_Copy(const void* data, const int kind, char* buffer, Py_ssize_t start, Py_ssize_t end) {
     int last_was_punctuation;
     Py_ssize_t i;
@@ -812,7 +812,7 @@ static double __Pyx_PyUnicode_AsDouble_WithSpaces(PyObject *obj) {
 
 static CYTHON_INLINE double __Pyx_PyUnicode_AsDouble(PyObject *obj) {
     // Currently not optimised for Py2.7.
-#if PY_MAJOR_VERSION >= 3 && !CYTHON_COMPILING_IN_PYPY
+#if PY_MAJOR_VERSION >= 3 && !CYTHON_COMPILING_IN_PYPY && CYTHON_ASSUME_SAFE_MACROS
     if (unlikely(__Pyx_PyUnicode_READY(obj) == -1))
         return (double)-1;
     if (likely(PyUnicode_IS_ASCII(obj))) {
@@ -834,10 +834,32 @@ static double __Pyx_SlowPyString_AsDouble(PyObject *obj);/*proto*/
 static double __Pyx__PyBytes_AsDouble(PyObject *obj, const char* start, Py_ssize_t length);/*proto*/
 
 static CYTHON_INLINE double __Pyx_PyBytes_AsDouble(PyObject *obj) {
-    return __Pyx__PyBytes_AsDouble(obj, PyBytes_AS_STRING(obj), PyBytes_GET_SIZE(obj));
+    char* as_c_string;
+    Py_ssize_t size;
+#if CYTHON_ASSUME_SAFE_MACROS
+    as_c_string = PyBytes_AS_STRING(obj);
+    size = PyBytes_GET_SIZE(obj);
+#else
+    if (PyBytes_AsStringAndSize(obj, &as_c_string, &size) < 0) {
+        return (double)-1;
+    }
+#endif
+    return __Pyx__PyBytes_AsDouble(obj, as_c_string, size);
 }
 static CYTHON_INLINE double __Pyx_PyByteArray_AsDouble(PyObject *obj) {
-    return __Pyx__PyBytes_AsDouble(obj, PyByteArray_AS_STRING(obj), PyByteArray_GET_SIZE(obj));
+    char* as_c_string;
+    Py_ssize_t size;
+#if CYTHON_ASSUME_SAFE_MACROS
+    as_c_string = PyByteArray_AS_STRING(obj);
+    size = PyByteArray_GET_SIZE(obj);
+#else
+    as_c_string = PyByteArray_AsString(obj);
+    if (as_c_string == NULL) {
+        return (double)-1;
+    }
+    size = PyByteArray_Size(obj);
+#endif
+    return __Pyx__PyBytes_AsDouble(obj, as_c_string, size);
 }
 
 
@@ -851,7 +873,11 @@ static double __Pyx_SlowPyString_AsDouble(PyObject *obj) {
     float_value = PyFloat_FromString(obj, 0);
 #endif
     if (likely(float_value)) {
+#if CYTHON_ASSUME_SAFE_MACROS
         double value = PyFloat_AS_DOUBLE(float_value);
+#else
+        double value = PyFloat_AsDouble(float_value);
+#endif
         Py_DECREF(float_value);
         return value;
     }

tests/run/isolated_limited_api_tests.srctree

@@ -40,6 +40,10 @@ limited.E()
 
 assert limited.decode(b'a', bytearray(b'b')) == "ab"
 
+assert limited.cast_float(1) == 1.0
+assert limited.cast_float("2.0") == 2.0
+assert limited.cast_float(bytearray(b"3")) == 3.0
+
 
 ##################### limited.pyx #############################
 
@@ -73,7 +77,10 @@ def raises():
 
 def decode(bytes b, bytearray ba):
     return b.decode("utf-8") + ba.decode("utf-8")
-
+
+def cast_float(object o):
+    return float(o)
+
 class C:
     pass