Issue #3163: The struct module gets new format characters 'n' and 'N'
supporting C integer types `ssize_t` and `size_t`, respectively.
diff --git a/Modules/_struct.c b/Modules/_struct.c
index 1604b90..dcdc83e 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -58,6 +58,7 @@
typedef struct { char c; float x; } st_float;
typedef struct { char c; double x; } st_double;
typedef struct { char c; void *x; } st_void_p;
+typedef struct { char c; size_t x; } st_size_t;
#define SHORT_ALIGN (sizeof(st_short) - sizeof(short))
#define INT_ALIGN (sizeof(st_int) - sizeof(int))
@@ -65,6 +66,7 @@
#define FLOAT_ALIGN (sizeof(st_float) - sizeof(float))
#define DOUBLE_ALIGN (sizeof(st_double) - sizeof(double))
#define VOID_P_ALIGN (sizeof(st_void_p) - sizeof(void *))
+#define SIZE_T_ALIGN (sizeof(st_size_t) - sizeof(size_t))
/* We can't support q and Q in native mode unless the compiler does;
in std mode, they're 8 bytes on all platforms. */
@@ -213,6 +215,52 @@
#endif
+/* Same, but handling Py_ssize_t */
+
+static int
+get_ssize_t(PyObject *v, Py_ssize_t *p)
+{
+ Py_ssize_t x;
+
+ v = get_pylong(v);
+ if (v == NULL)
+ return -1;
+ assert(PyLong_Check(v));
+ x = PyLong_AsSsize_t(v);
+ Py_DECREF(v);
+ if (x == (Py_ssize_t)-1 && PyErr_Occurred()) {
+ if (PyErr_ExceptionMatches(PyExc_OverflowError))
+ PyErr_SetString(StructError,
+ "argument out of range");
+ return -1;
+ }
+ *p = x;
+ return 0;
+}
+
+/* Same, but handling size_t */
+
+static int
+get_size_t(PyObject *v, size_t *p)
+{
+ size_t x;
+
+ v = get_pylong(v);
+ if (v == NULL)
+ return -1;
+ assert(PyLong_Check(v));
+ x = PyLong_AsSize_t(v);
+ Py_DECREF(v);
+ if (x == (size_t)-1 && PyErr_Occurred()) {
+ if (PyErr_ExceptionMatches(PyExc_OverflowError))
+ PyErr_SetString(StructError,
+ "argument out of range");
+ return -1;
+ }
+ *p = x;
+ return 0;
+}
+
#define RANGE_ERROR(x, f, flag, mask) return _range_error(f, flag)
@@ -369,6 +417,23 @@
return PyLong_FromUnsignedLong(x);
}
+static PyObject *
+nu_ssize_t(const char *p, const formatdef *f)
+{
+ Py_ssize_t x;
+ memcpy((char *)&x, p, sizeof x);
+ return PyLong_FromSsize_t(x);
+}
+
+static PyObject *
+nu_size_t(const char *p, const formatdef *f)
+{
+ size_t x;
+ memcpy((char *)&x, p, sizeof x);
+ return PyLong_FromSize_t(x);
+}
+
+
/* Native mode doesn't support q or Q unless the platform C supports
long long (or, on Windows, __int64). */
@@ -558,6 +623,26 @@
return 0;
}
+static int
+np_ssize_t(char *p, PyObject *v, const formatdef *f)
+{
+ Py_ssize_t x;
+ if (get_ssize_t(v, &x) < 0)
+ return -1;
+ memcpy(p, (char *)&x, sizeof x);
+ return 0;
+}
+
+static int
+np_size_t(char *p, PyObject *v, const formatdef *f)
+{
+ size_t x;
+ if (get_size_t(v, &x) < 0)
+ return -1;
+ memcpy(p, (char *)&x, sizeof x);
+ return 0;
+}
+
#ifdef HAVE_LONG_LONG
static int
@@ -651,6 +736,8 @@
{'I', sizeof(int), INT_ALIGN, nu_uint, np_uint},
{'l', sizeof(long), LONG_ALIGN, nu_long, np_long},
{'L', sizeof(long), LONG_ALIGN, nu_ulong, np_ulong},
+ {'n', sizeof(size_t), SIZE_T_ALIGN, nu_ssize_t, np_ssize_t},
+ {'N', sizeof(size_t), SIZE_T_ALIGN, nu_size_t, np_size_t},
#ifdef HAVE_LONG_LONG
{'q', sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_longlong, np_longlong},
{'Q', sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_ulonglong,np_ulonglong},
@@ -1951,7 +2038,8 @@
l:long; L:unsigned long; f:float; d:double.\n\
Special cases (preceding decimal count indicates length):\n\
s:string (array of char); p: pascal string (with count byte).\n\
-Special case (only available in native format):\n\
+Special cases (only available in native format):\n\
+ n:ssize_t; N:size_t;\n\
P:an integer type that is wide enough to hold a pointer.\n\
Special case (not in native mode unless 'long long' in platform C):\n\
q:long long; Q:unsigned long long\n\