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cpython/Modules/_struct.c
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Miss Islington (bot)andVictor Stinner 3a27a352f4 [3.14] gh-156939: Fix struct.pack('0p', bytes) (GH-157071) (#157130) 
gh-156939: Fix struct.pack('0p', bytes) (GH-157071)

If the Pascal string is empty (size=0), do not write the size prefix.
Previously, a NUL byte was written outsize the buffer (buffer
overflow). In practice, the write remains into allocated memory
and is silently ignored: no memory is corrupted.
(cherry picked from commit 23525c90f5)

Co-authored-by: Victor Stinner <vstinner@python.org>
2026-09-07 19:59:49 +00:00

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/* struct module -- pack values into and (out of) bytes objects */
/* New version supporting byte order, alignment and size options,
byte strings, and unsigned numbers */
#ifndef Py_BUILD_CORE_BUILTIN
# define Py_BUILD_CORE_MODULE 1
#endif
#include "Python.h"
#include "pycore_bytesobject.h" // _PyBytesWriter
#include "pycore_lock.h" // _PyOnceFlag_CallOnce()
#include "pycore_long.h" // _PyLong_AsByteArray()
#include "pycore_moduleobject.h" // _PyModule_GetState()
#include "pycore_weakref.h" // FT_CLEAR_WEAKREFS()
#include <stddef.h> // offsetof()
/*[clinic input]
class Struct "PyStructObject *" "&PyStructType"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=9b032058a83ed7c3]*/
typedef struct {
PyObject *cache;
PyObject *PyStructType;
PyObject *unpackiter_type;
PyObject *StructError;
} _structmodulestate;
static inline _structmodulestate*
get_struct_state(PyObject *module)
{
void *state = _PyModule_GetState(module);
assert(state != NULL);
return (_structmodulestate *)state;
}
static struct PyModuleDef _structmodule;
#define get_struct_state_structinst(self) \
(get_struct_state(PyType_GetModuleByDef(Py_TYPE(self), &_structmodule)))
#define get_struct_state_iterinst(self) \
(get_struct_state(PyType_GetModule(Py_TYPE(self))))
/* The translation function for each format character is table driven */
typedef struct _formatdef {
char format;
Py_ssize_t size;
Py_ssize_t alignment;
PyObject* (*unpack)(_structmodulestate *, const char *,
const struct _formatdef *);
int (*pack)(_structmodulestate *, char *, PyObject *,
const struct _formatdef *);
} formatdef;
typedef struct _formatcode {
const struct _formatdef *fmtdef;
Py_ssize_t offset;
Py_ssize_t size;
Py_ssize_t repeat;
} formatcode;
/* Struct object interface */
typedef struct {
PyObject_HEAD
Py_ssize_t s_size;
Py_ssize_t s_len;
formatcode *s_codes;
PyObject *s_format;
PyObject *weakreflist; /* List of weak references */
} PyStructObject;
#define PyStructObject_CAST(op) ((PyStructObject *)(op))
#define PyStruct_Check(op, state) PyObject_TypeCheck(op, (PyTypeObject *)(state)->PyStructType)
#ifdef __powerc
#pragma options align=reset
#endif
/*[python input]
class cache_struct_converter(CConverter):
type = 'PyStructObject *'
converter = 'cache_struct_converter'
c_default = "NULL"
broken_limited_capi = True
def parse_arg(self, argname, displayname, *, limited_capi):
assert not limited_capi
return self.format_code("""
if (!{converter}(module, {argname}, &{paramname})) {{{{
goto exit;
}}}}
""",
argname=argname,
converter=self.converter)
def cleanup(self):
return "Py_XDECREF(%s);\n" % self.name
[python start generated code]*/
/*[python end generated code: output=da39a3ee5e6b4b0d input=c33b27d6b06006c6]*/
static int cache_struct_converter(PyObject *, PyObject *, PyStructObject **);
#include "clinic/_struct.c.h"
/* Helper for integer format codes: converts an arbitrary Python object to a
PyLongObject if possible, otherwise fails. Caller should decref. */
static PyObject *
get_pylong(_structmodulestate *state, PyObject *v)
{
assert(v != NULL);
if (!PyLong_Check(v)) {
/* Not an integer; try to use __index__ to convert. */
if (PyIndex_Check(v)) {
v = _PyNumber_Index(v);
if (v == NULL)
return NULL;
}
else {
PyErr_SetString(state->StructError,
"required argument is not an integer");
return NULL;
}
}
else
Py_INCREF(v);
assert(PyLong_Check(v));
return v;
}
/* Helper routine to get a C long and raise the appropriate error if it isn't
one */
static int
get_long(_structmodulestate *state, PyObject *v, long *p)
{
long x;
v = get_pylong(state, v);
if (v == NULL)
return -1;
assert(PyLong_Check(v));
x = PyLong_AsLong(v);
Py_DECREF(v);
if (x == (long)-1 && PyErr_Occurred()) {
return -1;
}
*p = x;
return 0;
}
/* Same, but handling unsigned long */
static int
get_ulong(_structmodulestate *state, PyObject *v, unsigned long *p)
{
unsigned long x;
v = get_pylong(state, v);
if (v == NULL)
return -1;
assert(PyLong_Check(v));
x = PyLong_AsUnsignedLong(v);
Py_DECREF(v);
if (x == (unsigned long)-1 && PyErr_Occurred()) {
return -1;
}
*p = x;
return 0;
}
/* Same, but handling native long long. */
static int
get_longlong(_structmodulestate *state, PyObject *v, long long *p)
{
long long x;
v = get_pylong(state, v);
if (v == NULL)
return -1;
assert(PyLong_Check(v));
x = PyLong_AsLongLong(v);
Py_DECREF(v);
if (x == (long long)-1 && PyErr_Occurred()) {
return -1;
}
*p = x;
return 0;
}
/* Same, but handling native unsigned long long. */
static int
get_ulonglong(_structmodulestate *state, PyObject *v, unsigned long long *p)
{
unsigned long long x;
v = get_pylong(state, v);
if (v == NULL)
return -1;
assert(PyLong_Check(v));
x = PyLong_AsUnsignedLongLong(v);
Py_DECREF(v);
if (x == (unsigned long long)-1 && PyErr_Occurred()) {
return -1;
}
*p = x;
return 0;
}
/* Same, but handling Py_ssize_t */
static int
get_ssize_t(_structmodulestate *state, PyObject *v, Py_ssize_t *p)
{
Py_ssize_t x;
v = get_pylong(state, 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()) {
return -1;
}
*p = x;
return 0;
}
/* Same, but handling size_t */
static int
get_size_t(_structmodulestate *state, PyObject *v, size_t *p)
{
size_t x;
v = get_pylong(state, 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()) {
return -1;
}
*p = x;
return 0;
}
#define RANGE_ERROR(state, f, flag) return _range_error(state, f, flag)
/* Floating-point helpers */
static PyObject *
unpack_halffloat(const char *p, /* start of 2-byte string */
int le) /* true for little-endian, false for big-endian */
{
double x = PyFloat_Unpack2(p, le);
if (x == -1.0 && PyErr_Occurred()) {
return NULL;
}
return PyFloat_FromDouble(x);
}
static int
pack_halffloat(_structmodulestate *state,
char *p, /* start of 2-byte string */
PyObject *v, /* value to pack */
int le) /* true for little-endian, false for big-endian */
{
double x = PyFloat_AsDouble(v);
if (x == -1.0 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a float");
return -1;
}
return PyFloat_Pack2(x, p, le);
}
static PyObject *
unpack_float(const char *p, /* start of 4-byte string */
int le) /* true for little-endian, false for big-endian */
{
double x;
x = PyFloat_Unpack4(p, le);
if (x == -1.0 && PyErr_Occurred())
return NULL;
return PyFloat_FromDouble(x);
}
static PyObject *
unpack_double(const char *p, /* start of 8-byte string */
int le) /* true for little-endian, false for big-endian */
{
double x;
x = PyFloat_Unpack8(p, le);
if (x == -1.0 && PyErr_Occurred())
return NULL;
return PyFloat_FromDouble(x);
}
/* Helper to format the range error exceptions */
static int
_range_error(_structmodulestate *state, const formatdef *f, int is_unsigned)
{
/* ulargest is the largest unsigned value with f->size bytes.
* Note that the simpler:
* ((size_t)1 << (f->size * 8)) - 1
* doesn't work when f->size == sizeof(size_t) because C doesn't
* define what happens when a left shift count is >= the number of
* bits in the integer being shifted; e.g., on some boxes it doesn't
* shift at all when they're equal.
*/
const size_t ulargest = (size_t)-1 >> ((SIZEOF_SIZE_T - f->size)*8);
assert(f->size >= 1 && f->size <= SIZEOF_SIZE_T);
if (is_unsigned)
PyErr_Format(state->StructError,
"'%c' format requires 0 <= number <= %zu",
f->format,
ulargest);
else {
const Py_ssize_t largest = (Py_ssize_t)(ulargest >> 1);
PyErr_Format(state->StructError,
"'%c' format requires %zd <= number <= %zd",
f->format,
~ largest,
largest);
}
return -1;
}
/* A large number of small routines follow, with names of the form
[bln][up]_TYPE
[bln] distinguishes among big-endian, little-endian and native.
[pu] distinguishes between pack (to struct) and unpack (from struct).
TYPE is one of char, byte, ubyte, etc.
*/
/* Native mode routines. ****************************************************/
/* NOTE:
In all n[up]_<type> routines handling types larger than 1 byte, there is
*no* guarantee that the p pointer is properly aligned for each type,
therefore memcpy is called. An intermediate variable is used to
compensate for big-endian architectures.
Normally both the intermediate variable and the memcpy call will be
skipped by C optimisation in little-endian architectures (gcc >= 2.91
does this). */
static PyObject *
nu_char(_structmodulestate *state, const char *p, const formatdef *f)
{
return PyBytes_FromStringAndSize(p, 1);
}
static PyObject *
nu_byte(_structmodulestate *state, const char *p, const formatdef *f)
{
return PyLong_FromLong((long) *(signed char *)p);
}
static PyObject *
nu_ubyte(_structmodulestate *state, const char *p, const formatdef *f)
{
return PyLong_FromLong((long) *(unsigned char *)p);
}
static PyObject *
nu_short(_structmodulestate *state, const char *p, const formatdef *f)
{
short x;
memcpy(&x, p, sizeof x);
return PyLong_FromLong((long)x);
}
static PyObject *
nu_ushort(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned short x;
memcpy(&x, p, sizeof x);
return PyLong_FromLong((long)x);
}
static PyObject *
nu_int(_structmodulestate *state, const char *p, const formatdef *f)
{
int x;
memcpy(&x, p, sizeof x);
return PyLong_FromLong((long)x);
}
static PyObject *
nu_uint(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned int x;
memcpy(&x, p, sizeof x);
return PyLong_FromUnsignedLong((unsigned long)x);
}
static PyObject *
nu_long(_structmodulestate *state, const char *p, const formatdef *f)
{
long x;
memcpy(&x, p, sizeof x);
return PyLong_FromLong(x);
}
static PyObject *
nu_ulong(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long x;
memcpy(&x, p, sizeof x);
return PyLong_FromUnsignedLong(x);
}
static PyObject *
nu_ssize_t(_structmodulestate *state, const char *p, const formatdef *f)
{
Py_ssize_t x;
memcpy(&x, p, sizeof x);
return PyLong_FromSsize_t(x);
}
static PyObject *
nu_size_t(_structmodulestate *state, const char *p, const formatdef *f)
{
size_t x;
memcpy(&x, p, sizeof x);
return PyLong_FromSize_t(x);
}
static PyObject *
nu_longlong(_structmodulestate *state, const char *p, const formatdef *f)
{
long long x;
memcpy(&x, p, sizeof x);
return PyLong_FromLongLong(x);
}
static PyObject *
nu_ulonglong(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long long x;
memcpy(&x, p, sizeof x);
return PyLong_FromUnsignedLongLong(x);
}
static PyObject *
nu_bool(_structmodulestate *state, const char *p, const formatdef *f)
{
const _Bool bool_false = 0;
return PyBool_FromLong(memcmp(p, &bool_false, sizeof(_Bool)));
}
static PyObject *
nu_halffloat(_structmodulestate *state, const char *p, const formatdef *f)
{
#if PY_LITTLE_ENDIAN
return unpack_halffloat(p, 1);
#else
return unpack_halffloat(p, 0);
#endif
}
static PyObject *
nu_float(_structmodulestate *state, const char *p, const formatdef *f)
{
float x;
memcpy(&x, p, sizeof x);
return PyFloat_FromDouble((double)x);
}
static PyObject *
nu_double(_structmodulestate *state, const char *p, const formatdef *f)
{
double x;
memcpy(&x, p, sizeof x);
return PyFloat_FromDouble(x);
}
static PyObject *
nu_float_complex(_structmodulestate *state, const char *p, const formatdef *f)
{
float x[2];
memcpy(&x, p, sizeof(x));
return PyComplex_FromDoubles(x[0], x[1]);
}
static PyObject *
nu_double_complex(_structmodulestate *state, const char *p, const formatdef *f)
{
double x[2];
memcpy(&x, p, sizeof(x));
return PyComplex_FromDoubles(x[0], x[1]);
}
static PyObject *
nu_void_p(_structmodulestate *state, const char *p, const formatdef *f)
{
void *x;
memcpy(&x, p, sizeof x);
return PyLong_FromVoidPtr(x);
}
static int
np_byte(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long x;
if (get_long(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 0);
}
return -1;
}
if (x < -128 || x > 127) {
RANGE_ERROR(state, f, 0);
}
*p = (char)x;
return 0;
}
static int
np_ubyte(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long x;
if (get_long(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 1);
}
return -1;
}
if (x < 0 || x > 255) {
RANGE_ERROR(state, f, 1);
}
*(unsigned char *)p = (unsigned char)x;
return 0;
}
static int
np_char(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
if (!PyBytes_Check(v) || PyBytes_Size(v) != 1) {
PyErr_SetString(state->StructError,
"char format requires a bytes object of length 1");
return -1;
}
*p = *PyBytes_AS_STRING(v);
return 0;
}
static int
np_short(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long x;
short y;
if (get_long(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 0);
}
return -1;
}
if (x < SHRT_MIN || x > SHRT_MAX) {
RANGE_ERROR(state, f, 0);
}
y = (short)x;
memcpy(p, &y, sizeof y);
return 0;
}
static int
np_ushort(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long x;
unsigned short y;
if (get_long(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 1);
}
return -1;
}
if (x < 0 || x > USHRT_MAX) {
RANGE_ERROR(state, f, 1);
}
y = (unsigned short)x;
memcpy(p, &y, sizeof y);
return 0;
}
static int
np_int(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long x;
int y;
if (get_long(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 0);
}
return -1;
}
#if (SIZEOF_LONG > SIZEOF_INT)
if ((x < ((long)INT_MIN)) || (x > ((long)INT_MAX)))
RANGE_ERROR(state, f, 0);
#endif
y = (int)x;
memcpy(p, &y, sizeof y);
return 0;
}
static int
np_uint(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
unsigned long x;
unsigned int y;
if (get_ulong(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 1);
}
return -1;
}
y = (unsigned int)x;
#if (SIZEOF_LONG > SIZEOF_INT)
if (x > ((unsigned long)UINT_MAX))
RANGE_ERROR(state, f, 1);
#endif
memcpy(p, &y, sizeof y);
return 0;
}
static int
np_long(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long x;
if (get_long(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 0);
}
return -1;
}
memcpy(p, &x, sizeof x);
return 0;
}
static int
np_ulong(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
unsigned long x;
if (get_ulong(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 1);
}
return -1;
}
memcpy(p, &x, sizeof x);
return 0;
}
static int
np_ssize_t(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
Py_ssize_t x;
if (get_ssize_t(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 0);
}
return -1;
}
memcpy(p, &x, sizeof x);
return 0;
}
static int
np_size_t(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
size_t x;
if (get_size_t(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 1);
}
return -1;
}
memcpy(p, &x, sizeof x);
return 0;
}
static int
np_longlong(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long long x;
if (get_longlong(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
PyErr_Format(state->StructError,
"'%c' format requires %lld <= number <= %lld",
f->format,
LLONG_MIN,
LLONG_MAX);
}
return -1;
}
memcpy(p, &x, sizeof x);
return 0;
}
static int
np_ulonglong(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
unsigned long long x;
if (get_ulonglong(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
PyErr_Format(state->StructError,
"'%c' format requires 0 <= number <= %llu",
f->format,
ULLONG_MAX);
}
return -1;
}
memcpy(p, &x, sizeof x);
return 0;
}
static int
np_bool(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
int y;
_Bool x;
y = PyObject_IsTrue(v);
if (y < 0)
return -1;
x = y;
memcpy(p, &x, sizeof x);
return 0;
}
static int
np_halffloat(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
#if PY_LITTLE_ENDIAN
return pack_halffloat(state, p, v, 1);
#else
return pack_halffloat(state, p, v, 0);
#endif
}
static int
np_float(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
double x = PyFloat_AsDouble(v);
if (x == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a float");
return -1;
}
return PyFloat_Pack4(x, p, PY_LITTLE_ENDIAN);
}
static int
np_double(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
double x = PyFloat_AsDouble(v);
if (x == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a float");
return -1;
}
memcpy(p, &x, sizeof(double));
return 0;
}
static int
np_float_complex(_structmodulestate *state, char *p, PyObject *v,
const formatdef *f)
{
Py_complex c = PyComplex_AsCComplex(v);
float x[2] = {(float)c.real, (float)c.imag};
if (c.real == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a complex");
return -1;
}
memcpy(p, &x, sizeof(x));
return 0;
}
static int
np_double_complex(_structmodulestate *state, char *p, PyObject *v,
const formatdef *f)
{
Py_complex c = PyComplex_AsCComplex(v);
double x[2] = {c.real, c.imag};
if (c.real == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a complex");
return -1;
}
memcpy(p, &x, sizeof(x));
return 0;
}
static int
np_void_p(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
void *x;
v = get_pylong(state, v);
if (v == NULL)
return -1;
assert(PyLong_Check(v));
x = PyLong_AsVoidPtr(v);
Py_DECREF(v);
if (x == NULL && PyErr_Occurred())
return -1;
memcpy(p, &x, sizeof x);
return 0;
}
static const formatdef native_table[] = {
{'x', sizeof(char), 0, NULL},
{'b', sizeof(char), 0, nu_byte, np_byte},
{'B', sizeof(char), 0, nu_ubyte, np_ubyte},
{'c', sizeof(char), 0, nu_char, np_char},
{'s', sizeof(char), 0, NULL},
{'p', sizeof(char), 0, NULL},
{'h', sizeof(short), _Alignof(short), nu_short, np_short},
{'H', sizeof(short), _Alignof(short), nu_ushort, np_ushort},
{'i', sizeof(int), _Alignof(int), nu_int, np_int},
{'I', sizeof(int), _Alignof(int), nu_uint, np_uint},
{'l', sizeof(long), _Alignof(long), nu_long, np_long},
{'L', sizeof(long), _Alignof(long), nu_ulong, np_ulong},
{'n', sizeof(size_t), _Alignof(size_t), nu_ssize_t, np_ssize_t},
{'N', sizeof(size_t), _Alignof(size_t), nu_size_t, np_size_t},
{'q', sizeof(long long), _Alignof(long long), nu_longlong, np_longlong},
{'Q', sizeof(long long), _Alignof(long long), nu_ulonglong,np_ulonglong},
{'?', sizeof(_Bool), _Alignof(_Bool), nu_bool, np_bool},
{'e', sizeof(short), _Alignof(short), nu_halffloat, np_halffloat},
{'f', sizeof(float), _Alignof(float), nu_float, np_float},
{'d', sizeof(double), _Alignof(double), nu_double, np_double},
{'F', 2*sizeof(float), _Alignof(float), nu_float_complex, np_float_complex},
{'D', 2*sizeof(double), _Alignof(double), nu_double_complex, np_double_complex},
{'P', sizeof(void *), _Alignof(void *), nu_void_p, np_void_p},
{0}
};
/* Big-endian routines. *****************************************************/
static PyObject *
bu_short(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long x = 0;
/* This function is only ever used in the case f->size == 2. */
assert(f->size == 2);
Py_ssize_t i = 2;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | *bytes++;
} while (--i > 0);
/* Extend sign, avoiding implementation-defined or undefined behaviour. */
x = (x ^ 0x8000U) - 0x8000U;
return PyLong_FromLong(x & 0x8000U ? -1 - (long)(~x) : (long)x);
}
static PyObject *
bu_int(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long x = 0;
/* This function is only ever used in the case f->size == 4. */
assert(f->size == 4);
Py_ssize_t i = 4;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | *bytes++;
} while (--i > 0);
/* Extend sign, avoiding implementation-defined or undefined behaviour. */
x = (x ^ 0x80000000U) - 0x80000000U;
return PyLong_FromLong(x & 0x80000000U ? -1 - (long)(~x) : (long)x);
}
static PyObject *
bu_uint(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long x = 0;
Py_ssize_t i = f->size;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | *bytes++;
} while (--i > 0);
return PyLong_FromUnsignedLong(x);
}
static PyObject *
bu_longlong(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long long x = 0;
/* This function is only ever used in the case f->size == 8. */
assert(f->size == 8);
Py_ssize_t i = 8;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | *bytes++;
} while (--i > 0);
/* Extend sign, avoiding implementation-defined or undefined behaviour. */
x = (x ^ 0x8000000000000000U) - 0x8000000000000000U;
return PyLong_FromLongLong(
x & 0x8000000000000000U ? -1 - (long long)(~x) : (long long)x);
}
static PyObject *
bu_ulonglong(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long long x = 0;
Py_ssize_t i = f->size;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | *bytes++;
} while (--i > 0);
return PyLong_FromUnsignedLongLong(x);
}
static PyObject *
bu_halffloat(_structmodulestate *state, const char *p, const formatdef *f)
{
return unpack_halffloat(p, 0);
}
static PyObject *
bu_float(_structmodulestate *state, const char *p, const formatdef *f)
{
return unpack_float(p, 0);
}
static PyObject *
bu_double(_structmodulestate *state, const char *p, const formatdef *f)
{
return unpack_double(p, 0);
}
static PyObject *
bu_float_complex(_structmodulestate *state, const char *p, const formatdef *f)
{
double x = PyFloat_Unpack4(p, 0);
if (x == -1.0 && PyErr_Occurred()) {
return NULL;
}
double y = PyFloat_Unpack4(p + 4, 0);
if (y == -1.0 && PyErr_Occurred()) {
return NULL;
}
return PyComplex_FromDoubles(x, y);
}
static PyObject *
bu_double_complex(_structmodulestate *state, const char *p, const formatdef *f)
{
double x, y;
x = PyFloat_Unpack8(p, 0);
if (x == -1.0 && PyErr_Occurred()) {
return NULL;
}
y = PyFloat_Unpack8(p + 8, 0);
if (y == -1.0 && PyErr_Occurred()) {
return NULL;
}
return PyComplex_FromDoubles(x, y);
}
static PyObject *
bu_bool(_structmodulestate *state, const char *p, const formatdef *f)
{
return PyBool_FromLong(*p != 0);
}
static int
bp_int(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long x;
Py_ssize_t i;
unsigned char *q = (unsigned char *)p;
if (get_long(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 0);
}
return -1;
}
i = f->size;
if (i != SIZEOF_LONG) {
if ((i == 2) && (x < -32768 || x > 32767))
RANGE_ERROR(state, f, 0);
#if (SIZEOF_LONG != 4)
else if ((i == 4) && (x < -2147483648L || x > 2147483647L))
RANGE_ERROR(state, f, 0);
#endif
}
do {
q[--i] = (unsigned char)(x & 0xffL);
x >>= 8;
} while (i > 0);
return 0;
}
static int
bp_uint(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
unsigned long x;
Py_ssize_t i;
unsigned char *q = (unsigned char *)p;
if (get_ulong(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 1);
}
return -1;
}
i = f->size;
if (i != SIZEOF_LONG) {
unsigned long maxint = 1;
maxint <<= (unsigned long)(i * 8);
if (x >= maxint)
RANGE_ERROR(state, f, 1);
}
do {
q[--i] = (unsigned char)(x & 0xffUL);
x >>= 8;
} while (i > 0);
return 0;
}
static int
bp_longlong(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
int res;
v = get_pylong(state, v);
if (v == NULL)
return -1;
res = _PyLong_AsByteArray((PyLongObject *)v,
(unsigned char *)p,
8,
0, /* little_endian */
1, /* signed */
0 /* !with_exceptions */);
Py_DECREF(v);
if (res < 0) {
PyErr_Format(state->StructError,
"'%c' format requires %lld <= number <= %lld",
f->format,
LLONG_MIN,
LLONG_MAX);
return -1;
}
return res;
}
static int
bp_ulonglong(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
int res;
v = get_pylong(state, v);
if (v == NULL)
return -1;
res = _PyLong_AsByteArray((PyLongObject *)v,
(unsigned char *)p,
8,
0, /* little_endian */
0, /* signed */
0 /* !with_exceptions */);
Py_DECREF(v);
if (res < 0) {
PyErr_Format(state->StructError,
"'%c' format requires 0 <= number <= %llu",
f->format,
ULLONG_MAX);
return -1;
}
return res;
}
static int
bp_halffloat(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
return pack_halffloat(state, p, v, 0);
}
static int
bp_float(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
double x = PyFloat_AsDouble(v);
if (x == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a float");
return -1;
}
return PyFloat_Pack4(x, p, 0);
}
static int
bp_double(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
double x = PyFloat_AsDouble(v);
if (x == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a float");
return -1;
}
return PyFloat_Pack8(x, p, 0);
}
static int
bp_float_complex(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
Py_complex x = PyComplex_AsCComplex(v);
if (x.real == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a complex");
return -1;
}
if (PyFloat_Pack4(x.real, p, 0)) {
return -1;
}
return PyFloat_Pack4(x.imag, p + 4, 0);
}
static int
bp_double_complex(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
Py_complex x = PyComplex_AsCComplex(v);
if (x.real == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a complex");
return -1;
}
if (PyFloat_Pack8(x.real, p, 0)) {
return -1;
}
return PyFloat_Pack8(x.imag, p + 8, 0);
}
static int
bp_bool(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
int y;
y = PyObject_IsTrue(v);
if (y < 0)
return -1;
*p = (char)y;
return 0;
}
static formatdef bigendian_table[] = {
{'x', 1, 0, NULL},
{'b', 1, 0, nu_byte, np_byte},
{'B', 1, 0, nu_ubyte, np_ubyte},
{'c', 1, 0, nu_char, np_char},
{'s', 1, 0, NULL},
{'p', 1, 0, NULL},
{'h', 2, 0, bu_short, bp_int},
{'H', 2, 0, bu_uint, bp_uint},
{'i', 4, 0, bu_int, bp_int},
{'I', 4, 0, bu_uint, bp_uint},
{'l', 4, 0, bu_int, bp_int},
{'L', 4, 0, bu_uint, bp_uint},
{'q', 8, 0, bu_longlong, bp_longlong},
{'Q', 8, 0, bu_ulonglong, bp_ulonglong},
{'?', 1, 0, bu_bool, bp_bool},
{'e', 2, 0, bu_halffloat, bp_halffloat},
{'f', 4, 0, bu_float, bp_float},
{'d', 8, 0, bu_double, bp_double},
{'F', 8, 0, bu_float_complex, bp_float_complex},
{'D', 16, 0, bu_double_complex, bp_double_complex},
{0}
};
/* Little-endian routines. *****************************************************/
static PyObject *
lu_short(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long x = 0;
/* This function is only ever used in the case f->size == 2. */
assert(f->size == 2);
Py_ssize_t i = 2;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | bytes[--i];
} while (i > 0);
/* Extend sign, avoiding implementation-defined or undefined behaviour. */
x = (x ^ 0x8000U) - 0x8000U;
return PyLong_FromLong(x & 0x8000U ? -1 - (long)(~x) : (long)x);
}
static PyObject *
lu_int(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long x = 0;
/* This function is only ever used in the case f->size == 4. */
assert(f->size == 4);
Py_ssize_t i = 4;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | bytes[--i];
} while (i > 0);
/* Extend sign, avoiding implementation-defined or undefined behaviour. */
x = (x ^ 0x80000000U) - 0x80000000U;
return PyLong_FromLong(x & 0x80000000U ? -1 - (long)(~x) : (long)x);
}
static PyObject *
lu_uint(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long x = 0;
Py_ssize_t i = f->size;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | bytes[--i];
} while (i > 0);
return PyLong_FromUnsignedLong(x);
}
static PyObject *
lu_longlong(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long long x = 0;
/* This function is only ever used in the case f->size == 8. */
assert(f->size == 8);
Py_ssize_t i = 8;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | bytes[--i];
} while (i > 0);
/* Extend sign, avoiding implementation-defined or undefined behaviour. */
x = (x ^ 0x8000000000000000U) - 0x8000000000000000U;
return PyLong_FromLongLong(
x & 0x8000000000000000U ? -1 - (long long)(~x) : (long long)x);
}
static PyObject *
lu_ulonglong(_structmodulestate *state, const char *p, const formatdef *f)
{
unsigned long long x = 0;
Py_ssize_t i = f->size;
const unsigned char *bytes = (const unsigned char *)p;
do {
x = (x<<8) | bytes[--i];
} while (i > 0);
return PyLong_FromUnsignedLongLong(x);
}
static PyObject *
lu_halffloat(_structmodulestate *state, const char *p, const formatdef *f)
{
return unpack_halffloat(p, 1);
}
static PyObject *
lu_float(_structmodulestate *state, const char *p, const formatdef *f)
{
return unpack_float(p, 1);
}
static PyObject *
lu_double(_structmodulestate *state, const char *p, const formatdef *f)
{
return unpack_double(p, 1);
}
static PyObject *
lu_float_complex(_structmodulestate *state, const char *p, const formatdef *f)
{
double x = PyFloat_Unpack4(p, 1);
if (x == -1.0 && PyErr_Occurred()) {
return NULL;
}
double y = PyFloat_Unpack4(p + 4, 1);
if (y == -1.0 && PyErr_Occurred()) {
return NULL;
}
return PyComplex_FromDoubles(x, y);
}
static PyObject *
lu_double_complex(_structmodulestate *state, const char *p, const formatdef *f)
{
double x, y;
x = PyFloat_Unpack8(p, 1);
if (x == -1.0 && PyErr_Occurred()) {
return NULL;
}
y = PyFloat_Unpack8(p + 8, 1);
if (y == -1.0 && PyErr_Occurred()) {
return NULL;
}
return PyComplex_FromDoubles(x, y);
}
static int
lp_int(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
long x;
Py_ssize_t i;
unsigned char *q = (unsigned char *)p;
if (get_long(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 0);
}
return -1;
}
i = f->size;
if (i != SIZEOF_LONG) {
if ((i == 2) && (x < -32768 || x > 32767))
RANGE_ERROR(state, f, 0);
#if (SIZEOF_LONG != 4)
else if ((i == 4) && (x < -2147483648L || x > 2147483647L))
RANGE_ERROR(state, f, 0);
#endif
}
do {
*q++ = (unsigned char)(x & 0xffL);
x >>= 8;
} while (--i > 0);
return 0;
}
static int
lp_uint(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
unsigned long x;
Py_ssize_t i;
unsigned char *q = (unsigned char *)p;
if (get_ulong(state, v, &x) < 0) {
if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
RANGE_ERROR(state, f, 1);
}
return -1;
}
i = f->size;
if (i != SIZEOF_LONG) {
unsigned long maxint = 1;
maxint <<= (unsigned long)(i * 8);
if (x >= maxint)
RANGE_ERROR(state, f, 1);
}
do {
*q++ = (unsigned char)(x & 0xffUL);
x >>= 8;
} while (--i > 0);
return 0;
}
static int
lp_longlong(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
int res;
v = get_pylong(state, v);
if (v == NULL)
return -1;
res = _PyLong_AsByteArray((PyLongObject*)v,
(unsigned char *)p,
8,
1, /* little_endian */
1, /* signed */
0 /* !with_exceptions */);
Py_DECREF(v);
if (res < 0) {
PyErr_Format(state->StructError,
"'%c' format requires %lld <= number <= %lld",
f->format,
LLONG_MIN,
LLONG_MAX);
return -1;
}
return res;
}
static int
lp_ulonglong(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
int res;
v = get_pylong(state, v);
if (v == NULL)
return -1;
res = _PyLong_AsByteArray((PyLongObject*)v,
(unsigned char *)p,
8,
1, /* little_endian */
0, /* signed */
0 /* !with_exceptions */);
Py_DECREF(v);
if (res < 0) {
PyErr_Format(state->StructError,
"'%c' format requires 0 <= number <= %llu",
f->format,
ULLONG_MAX);
return -1;
}
return res;
}
static int
lp_halffloat(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
return pack_halffloat(state, p, v, 1);
}
static int
lp_float(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
double x = PyFloat_AsDouble(v);
if (x == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a float");
return -1;
}
return PyFloat_Pack4(x, p, 1);
}
static int
lp_double(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
double x = PyFloat_AsDouble(v);
if (x == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a float");
return -1;
}
return PyFloat_Pack8(x, p, 1);
}
static int
lp_float_complex(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
Py_complex x = PyComplex_AsCComplex(v);
if (x.real == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a complex");
return -1;
}
if (PyFloat_Pack4(x.real, p, 1)) {
return -1;
}
return PyFloat_Pack4(x.imag, p + 4, 1);
}
static int
lp_double_complex(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)
{
Py_complex x = PyComplex_AsCComplex(v);
if (x.real == -1 && PyErr_Occurred()) {
PyErr_SetString(state->StructError,
"required argument is not a complex");
return -1;
}
if (PyFloat_Pack8(x.real, p, 1)) {
return -1;
}
return PyFloat_Pack8(x.imag, p + 8, 1);
}
static formatdef lilendian_table[] = {
{'x', 1, 0, NULL},
{'b', 1, 0, nu_byte, np_byte},
{'B', 1, 0, nu_ubyte, np_ubyte},
{'c', 1, 0, nu_char, np_char},
{'s', 1, 0, NULL},
{'p', 1, 0, NULL},
{'h', 2, 0, lu_short, lp_int},
{'H', 2, 0, lu_uint, lp_uint},
{'i', 4, 0, lu_int, lp_int},
{'I', 4, 0, lu_uint, lp_uint},
{'l', 4, 0, lu_int, lp_int},
{'L', 4, 0, lu_uint, lp_uint},
{'q', 8, 0, lu_longlong, lp_longlong},
{'Q', 8, 0, lu_ulonglong, lp_ulonglong},
{'?', 1, 0, bu_bool, bp_bool}, /* Std rep not endian dep,
but potentially different from native rep -- reuse bx_bool funcs. */
{'e', 2, 0, lu_halffloat, lp_halffloat},
{'f', 4, 0, lu_float, lp_float},
{'d', 8, 0, lu_double, lp_double},
{'F', 8, 0, lu_float_complex, lp_float_complex},
{'D', 16, 0, lu_double_complex, lp_double_complex},
{0}
};
/* Ensure endian table optimization happens exactly once across all interpreters */
static _PyOnceFlag endian_tables_init_once = {0};
static int
init_endian_tables(void *Py_UNUSED(arg))
{
const formatdef *native = native_table;
formatdef *other, *ptr;
#if PY_LITTLE_ENDIAN
other = lilendian_table;
#else
other = bigendian_table;
#endif
/* Scan through the native table, find a matching
entry in the endian table and swap in the
native implementations whenever possible
(64-bit platforms may not have "standard" sizes) */
while (native->format != '\0' && other->format != '\0') {
ptr = other;
while (ptr->format != '\0') {
if (ptr->format == native->format) {
/* Match faster when formats are
listed in the same order */
if (ptr == other)
other++;
/* Only use the trick if the
size matches */
if (ptr->size != native->size)
break;
/* Skip float and double, could be
"unknown" float format */
if (ptr->format == 'd' || ptr->format == 'f')
break;
/* Skip _Bool, semantics are different for standard size */
if (ptr->format == '?')
break;
ptr->pack = native->pack;
ptr->unpack = native->unpack;
break;
}
ptr++;
}
native++;
}
return 0;
}
static const formatdef *
whichtable(const char **pfmt)
{
const char *fmt = (*pfmt)++; /* May be backed out of later */
switch (*fmt) {
case '<':
return lilendian_table;
case '>':
case '!': /* Network byte order is big-endian */
return bigendian_table;
case '=': { /* Host byte order -- different from native in alignment! */
#if PY_LITTLE_ENDIAN
return lilendian_table;
#else
return bigendian_table;
#endif
}
default:
--*pfmt; /* Back out of pointer increment */
_Py_FALLTHROUGH;
case '@':
return native_table;
}
}
/* Get the table entry for a format code */
static const formatdef *
getentry(_structmodulestate *state, int c, const formatdef *f)
{
for (; f->format != '\0'; f++) {
if (f->format == c) {
return f;
}
}
PyErr_SetString(state->StructError, "bad char in struct format");
return NULL;
}
/* Align a size according to a format code. Return -1 on overflow. */
static Py_ssize_t
align(Py_ssize_t size, char c, const formatdef *e)
{
Py_ssize_t extra;
if (e->format == c) {
if (e->alignment && size > 0) {
extra = (e->alignment - 1) - (size - 1) % (e->alignment);
if (extra > PY_SSIZE_T_MAX - size)
return -1;
size += extra;
}
}
return size;
}
/*
* Struct object implementation.
*/
/* calculate the size of a format string */
static int
prepare_s(PyStructObject *self, PyObject *format)
{
const formatdef *f;
const formatdef *e;
formatcode *codes, *codes0;
const char *s;
const char *fmt;
char c;
Py_ssize_t size, len, num, itemsize;
size_t ncodes;
_structmodulestate *state = get_struct_state_structinst(self);
fmt = PyBytes_AS_STRING(format);
if (strlen(fmt) != (size_t)PyBytes_GET_SIZE(format)) {
PyErr_SetString(state->StructError,
"embedded null character");
return -1;
}
f = whichtable(&fmt);
s = fmt;
size = 0;
len = 0;
ncodes = 0;
while ((c = *s++) != '\0') {
if (Py_ISSPACE(c))
continue;
if ('0' <= c && c <= '9') {
num = c - '0';
while ('0' <= (c = *s++) && c <= '9') {
/* overflow-safe version of
if (num*10 + (c - '0') > PY_SSIZE_T_MAX) { ... } */
if (num >= PY_SSIZE_T_MAX / 10 && (
num > PY_SSIZE_T_MAX / 10 ||
(c - '0') > PY_SSIZE_T_MAX % 10))
goto overflow;
num = num*10 + (c - '0');
}
if (c == '\0') {
PyErr_SetString(state->StructError,
"repeat count given without format specifier");
return -1;
}
}
else
num = 1;
e = getentry(state, c, f);
if (e == NULL)
return -1;
switch (c) {
case 's': _Py_FALLTHROUGH;
case 'p':
if (len == PY_SSIZE_T_MAX) {
goto overflow;
}
len++;
ncodes++;
break;
case 'x': break;
default:
if (num > PY_SSIZE_T_MAX - len) {
goto overflow;
}
len += num;
if (num) {
ncodes++;
}
break;
}
itemsize = e->size;
size = align(size, c, e);
if (size == -1)
goto overflow;
/* if (size + num * itemsize > PY_SSIZE_T_MAX) { ... } */
if (num > (PY_SSIZE_T_MAX - size) / itemsize)
goto overflow;
size += num * itemsize;
}
/* check for overflow */
if ((ncodes + 1) > ((size_t)PY_SSIZE_T_MAX / sizeof(formatcode))) {
PyErr_NoMemory();
return -1;
}
codes = PyMem_Malloc((ncodes + 1) * sizeof(formatcode));
if (codes == NULL) {
PyErr_NoMemory();
return -1;
}
codes0 = codes;
s = fmt;
size = 0;
while ((c = *s++) != '\0') {
if (Py_ISSPACE(c))
continue;
if ('0' <= c && c <= '9') {
num = c - '0';
while ('0' <= (c = *s++) && c <= '9')
num = num*10 + (c - '0');
}
else
num = 1;
e = getentry(state, c, f);
size = align(size, c, e);
if (c == 's' || c == 'p') {
codes->offset = size;
codes->size = num;
codes->fmtdef = e;
codes->repeat = 1;
codes++;
size += num;
} else if (c == 'x') {
size += num;
} else if (num) {
codes->offset = size;
codes->size = e->size;
codes->fmtdef = e;
codes->repeat = num;
codes++;
size += e->size * num;
}
}
codes->fmtdef = NULL;
codes->offset = size;
codes->size = 0;
codes->repeat = 0;
/* Free any s_codes value left over from a previous initialization. */
if (self->s_codes != NULL)
PyMem_Free(self->s_codes);
self->s_codes = codes0;
self->s_size = size;
self->s_len = len;
Py_XSETREF(self->s_format, Py_NewRef(format));
return 0;
overflow:
PyErr_SetString(state->StructError,
"total struct size too long");
return -1;
}
static PyObject *
s_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
PyObject *self;
assert(type != NULL);
allocfunc alloc_func = PyType_GetSlot(type, Py_tp_alloc);
assert(alloc_func != NULL);
self = alloc_func(type, 0);
if (self != NULL) {
PyStructObject *s = (PyStructObject*)self;
s->s_format = Py_NewRef(Py_None);
s->s_codes = NULL;
s->s_size = -1;
s->s_len = -1;
}
return self;
}
/*[clinic input]
Struct.__init__
format: object
Create a compiled struct object.
Return a new Struct object which writes and reads binary data according to
the format string.
See help(struct) for more on format strings.
[clinic start generated code]*/
static int
Struct___init___impl(PyStructObject *self, PyObject *format)
/*[clinic end generated code: output=b8e80862444e92d0 input=192a4575a3dde802]*/
{
int ret = 0;
if (PyUnicode_Check(format)) {
format = PyUnicode_AsASCIIString(format);
if (format == NULL)
return -1;
}
else {
Py_INCREF(format);
}
if (!PyBytes_Check(format)) {
Py_DECREF(format);
PyErr_Format(PyExc_TypeError,
"Struct() argument 1 must be a str or bytes object, "
"not %.200s",
_PyType_Name(Py_TYPE(format)));
return -1;
}
ret = prepare_s(self, format);
Py_DECREF(format);
return ret;
}
static int
s_clear(PyObject *op)
{
PyStructObject *s = PyStructObject_CAST(op);
Py_CLEAR(s->s_format);
return 0;
}
static int
s_traverse(PyObject *op, visitproc visit, void *arg)
{
PyStructObject *s = PyStructObject_CAST(op);
Py_VISIT(Py_TYPE(s));
Py_VISIT(s->s_format);
return 0;
}
static void
s_dealloc(PyObject *op)
{
PyStructObject *s = PyStructObject_CAST(op);
PyTypeObject *tp = Py_TYPE(s);
PyObject_GC_UnTrack(s);
FT_CLEAR_WEAKREFS(op, s->weakreflist);
if (s->s_codes != NULL) {
PyMem_Free(s->s_codes);
}
Py_XDECREF(s->s_format);
tp->tp_free(s);
Py_DECREF(tp);
}
static PyObject *
s_unpack_internal(PyStructObject *soself, const char *startfrom,
_structmodulestate *state) {
formatcode *code;
Py_ssize_t i = 0;
PyObject *result = PyTuple_New(soself->s_len);
if (result == NULL)
return NULL;
for (code = soself->s_codes; code->fmtdef != NULL; code++) {
const formatdef *e = code->fmtdef;
const char *res = startfrom + code->offset;
Py_ssize_t j = code->repeat;
while (j--) {
PyObject *v;
if (e->format == 's') {
v = PyBytes_FromStringAndSize(res, code->size);
} else if (e->format == 'p') {
Py_ssize_t n;
if (code->size == 0) {
n = 0;
}
else {
n = *(unsigned char*)res;
if (n >= code->size) {
n = code->size - 1;
}
}
v = PyBytes_FromStringAndSize(res + 1, n);
} else {
v = e->unpack(state, res, e);
}
if (v == NULL)
goto fail;
PyTuple_SET_ITEM(result, i++, v);
res += code->size;
}
}
return result;
fail:
Py_DECREF(result);
return NULL;
}
#define ENSURE_STRUCT_IS_READY(self) \
do { \
if (!(self)->s_codes) { \
PyErr_SetString(PyExc_RuntimeError, \
"Struct object is not initialized"); \
return NULL; \
} \
} while (0);
/*[clinic input]
Struct.unpack
buffer: Py_buffer
/
Return a tuple containing unpacked values.
Unpack according to the format string Struct.format. The buffer's size
in bytes must be Struct.size.
See help(struct) for more on format strings.
[clinic start generated code]*/
static PyObject *
Struct_unpack_impl(PyStructObject *self, Py_buffer *buffer)
/*[clinic end generated code: output=873a24faf02e848a input=3113f8e7038b2f6c]*/
{
_structmodulestate *state = get_struct_state_structinst(self);
ENSURE_STRUCT_IS_READY(self);
if (buffer->len != self->s_size) {
PyErr_Format(state->StructError,
"unpack requires a buffer of %zd bytes",
self->s_size);
return NULL;
}
return s_unpack_internal(self, buffer->buf, state);
}
/*[clinic input]
Struct.unpack_from
buffer: Py_buffer
offset: Py_ssize_t = 0
Return a tuple containing unpacked values.
Values are unpacked according to the format string Struct.format.
The buffer's size in bytes, starting at position offset, must be
at least Struct.size. A negative offset counts from the end of the
buffer.
See help(struct) for more on format strings.
[clinic start generated code]*/
static PyObject *
Struct_unpack_from_impl(PyStructObject *self, Py_buffer *buffer,
Py_ssize_t offset)
/*[clinic end generated code: output=57fac875e0977316 input=3451f778ed8a5345]*/
{
_structmodulestate *state = get_struct_state_structinst(self);
ENSURE_STRUCT_IS_READY(self);
if (offset < 0) {
if (offset + self->s_size > 0) {
PyErr_Format(state->StructError,
"not enough data to unpack %zd bytes at offset %zd",
self->s_size,
offset);
return NULL;
}
if (offset + buffer->len < 0) {
PyErr_Format(state->StructError,
"offset %zd out of range for %zd-byte buffer",
offset,
buffer->len);
return NULL;
}
offset += buffer->len;
}
if ((buffer->len - offset) < self->s_size) {
PyErr_Format(state->StructError,
"unpack_from requires a buffer of at least %zu bytes for "
"unpacking %zd bytes at offset %zd "
"(actual buffer size is %zd)",
(size_t)self->s_size + (size_t)offset,
self->s_size,
offset,
buffer->len);
return NULL;
}
return s_unpack_internal(self, (char*)buffer->buf + offset, state);
}
/* Unpack iterator type */
typedef struct {
PyObject_HEAD
PyStructObject *so;
Py_buffer buf;
Py_ssize_t index;
} unpackiterobject;
#define unpackiterobject_CAST(op) ((unpackiterobject *)(op))
static void
unpackiter_dealloc(PyObject *op)
{
unpackiterobject *self = unpackiterobject_CAST(op);
/* bpo-31095: UnTrack is needed before calling any callbacks */
PyTypeObject *tp = Py_TYPE(self);
PyObject_GC_UnTrack(self);
Py_XDECREF(self->so);
PyBuffer_Release(&self->buf);
PyObject_GC_Del(self);
Py_DECREF(tp);
}
static int
unpackiter_traverse(PyObject *op, visitproc visit, void *arg)
{
unpackiterobject *self = unpackiterobject_CAST(op);
Py_VISIT(Py_TYPE(self));
Py_VISIT(self->so);
Py_VISIT(self->buf.obj);
return 0;
}
static PyObject *
unpackiter_len(PyObject *op, PyObject *Py_UNUSED(dummy))
{
Py_ssize_t len;
unpackiterobject *self = unpackiterobject_CAST(op);
if (self->so == NULL) {
len = 0;
}
else {
len = (self->buf.len - self->index) / self->so->s_size;
}
return PyLong_FromSsize_t(len);
}
static PyMethodDef unpackiter_methods[] = {
{"__length_hint__", unpackiter_len, METH_NOARGS, NULL},
{NULL, NULL} /* sentinel */
};
static PyObject *
unpackiter_iternext(PyObject *op)
{
unpackiterobject *self = unpackiterobject_CAST(op);
_structmodulestate *state = get_struct_state_iterinst(self);
PyObject *result;
if (self->so == NULL) {
return NULL;
}
if (self->index >= self->buf.len) {
/* Iterator exhausted */
Py_CLEAR(self->so);
PyBuffer_Release(&self->buf);
return NULL;
}
assert(self->index + self->so->s_size <= self->buf.len);
result = s_unpack_internal(self->so,
(char*)self->buf.buf + self->index,
state);
self->index += self->so->s_size;
return result;
}
static PyType_Slot unpackiter_type_slots[] = {
{Py_tp_dealloc, unpackiter_dealloc},
{Py_tp_getattro, PyObject_GenericGetAttr},
{Py_tp_traverse, unpackiter_traverse},
{Py_tp_iter, PyObject_SelfIter},
{Py_tp_iternext, unpackiter_iternext},
{Py_tp_methods, unpackiter_methods},
{0, 0},
};
static PyType_Spec unpackiter_type_spec = {
"_struct.unpack_iterator",
sizeof(unpackiterobject),
0,
(Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_IMMUTABLETYPE | Py_TPFLAGS_DISALLOW_INSTANTIATION),
unpackiter_type_slots
};
/*[clinic input]
Struct.iter_unpack
buffer: object
/
Return an iterator yielding tuples.
Tuples are unpacked from the given bytes source, like a repeated
invocation of unpack_from().
Requires that the bytes length be a multiple of the struct size.
[clinic start generated code]*/
static PyObject *
Struct_iter_unpack_impl(PyStructObject *self, PyObject *buffer)
/*[clinic end generated code: output=818f89ad4afa8d64 input=6d65b3f3107dbc99]*/
{
_structmodulestate *state = get_struct_state_structinst(self);
unpackiterobject *iter;
ENSURE_STRUCT_IS_READY(self);
if (self->s_size == 0) {
PyErr_Format(state->StructError,
"cannot iteratively unpack with a struct of length 0");
return NULL;
}
iter = (unpackiterobject *) PyType_GenericAlloc((PyTypeObject *)state->unpackiter_type, 0);
if (iter == NULL)
return NULL;
if (PyObject_GetBuffer(buffer, &iter->buf, PyBUF_SIMPLE) < 0) {
Py_DECREF(iter);
return NULL;
}
if (iter->buf.len % self->s_size != 0) {
PyErr_Format(state->StructError,
"iterative unpacking requires a buffer of "
"a multiple of %zd bytes",
self->s_size);
Py_DECREF(iter);
return NULL;
}
iter->so = (PyStructObject*)Py_NewRef(self);
iter->index = 0;
return (PyObject *)iter;
}
/*
* Guts of the pack function.
*
* Takes a struct object, a tuple of arguments, and offset in that tuple of
* argument for where to start processing the arguments for packing, and a
* character buffer for writing the packed data. The caller must ensure
* that the buffer may contain the required length for packing the arguments.
* 0 is returned on success, 1 is returned if there is an error.
*
*/
static int
s_pack_internal(PyStructObject *soself, PyObject *const *args, int offset,
char* buf, _structmodulestate *state)
{
formatcode *code;
/* XXX(nnorwitz): why does i need to be a local? can we use
the offset parameter or do we need the wider width? */
Py_ssize_t i;
memset(buf, '\0', soself->s_size);
i = offset;
for (code = soself->s_codes; code->fmtdef != NULL; code++) {
const formatdef *e = code->fmtdef;
char *res = buf + code->offset;
Py_ssize_t j = code->repeat;
while (j--) {
PyObject *v = args[i++];
if (e->format == 's') {
Py_ssize_t n;
int isstring;
const void *p;
isstring = PyBytes_Check(v);
if (!isstring && !PyByteArray_Check(v)) {
PyErr_SetString(state->StructError,
"argument for 's' must be a bytes object");
return -1;
}
if (isstring) {
n = PyBytes_GET_SIZE(v);
p = PyBytes_AS_STRING(v);
}
else {
n = PyByteArray_GET_SIZE(v);
p = PyByteArray_AS_STRING(v);
}
if (n > code->size)
n = code->size;
if (n > 0)
memcpy(res, p, n);
} else if (e->format == 'p') {
Py_ssize_t n;
int isstring;
const void *p;
isstring = PyBytes_Check(v);
if (!isstring && !PyByteArray_Check(v)) {
PyErr_SetString(state->StructError,
"argument for 'p' must be a bytes object");
return -1;
}
if (isstring) {
n = PyBytes_GET_SIZE(v);
p = PyBytes_AS_STRING(v);
}
else {
n = PyByteArray_GET_SIZE(v);
p = PyByteArray_AS_STRING(v);
}
if (code->size == 0) {
n = 0;
}
else if (n > (code->size - 1)) {
n = code->size - 1;
}
if (n > 0)
memcpy(res + 1, p, n);
if (n > 255)
n = 255;
if (n > 0) {
*res = Py_SAFE_DOWNCAST(n, Py_ssize_t, unsigned char);
}
} else {
if (e->pack(state, res, v, e) < 0) {
if (PyLong_Check(v) && PyErr_ExceptionMatches(PyExc_OverflowError))
PyErr_SetString(state->StructError,
"int too large to convert");
return -1;
}
}
res += code->size;
}
}
/* Success */
return 0;
}
PyDoc_STRVAR(s_pack__doc__,
"S.pack(v1, v2, ...) -> bytes\n\
\n\
Return a bytes object containing values v1, v2, ... packed according\n\
to the format string S.format. See help(struct) for more on format\n\
strings.");
static PyObject *
s_pack(PyObject *self, PyObject *const *args, Py_ssize_t nargs)
{
char *buf;
PyStructObject *soself;
_structmodulestate *state = get_struct_state_structinst(self);
/* Validate arguments. */
soself = PyStructObject_CAST(self);
ENSURE_STRUCT_IS_READY(soself);
assert(PyStruct_Check(self, state));
if (nargs != soself->s_len)
{
PyErr_Format(state->StructError,
"pack expected %zd items for packing (got %zd)", soself->s_len, nargs);
return NULL;
}
/* Allocate a new string */
_PyBytesWriter writer;
_PyBytesWriter_Init(&writer);
buf = _PyBytesWriter_Alloc(&writer, soself->s_size);
if (buf == NULL) {
_PyBytesWriter_Dealloc(&writer);
return NULL;
}
/* Call the guts */
if ( s_pack_internal(soself, args, 0, buf, state) != 0 ) {
_PyBytesWriter_Dealloc(&writer);
return NULL;
}
return _PyBytesWriter_Finish(&writer, buf + soself->s_size);
}
PyDoc_STRVAR(s_pack_into__doc__,
"S.pack_into(buffer, offset, v1, v2, ...)\n\
\n\
Pack the values v1, v2, ... according to the format string S.format\n\
and write the packed bytes into the writable buffer buf starting at\n\
offset. Note that the offset is a required argument. A negative\n\
offset counts from the end of the buffer. See help(struct) for more\n\
on format strings.");
static PyObject *
s_pack_into(PyObject *self, PyObject *const *args, Py_ssize_t nargs)
{
PyStructObject *soself;
Py_buffer buffer;
Py_ssize_t offset;
_structmodulestate *state = get_struct_state_structinst(self);
/* Validate arguments. +1 is for the first arg as buffer. */
soself = PyStructObject_CAST(self);
ENSURE_STRUCT_IS_READY(soself);
assert(PyStruct_Check(self, state));
if (nargs != (soself->s_len + 2))
{
if (nargs == 0) {
PyErr_Format(state->StructError,
"pack_into expected buffer argument");
}
else if (nargs == 1) {
PyErr_Format(state->StructError,
"pack_into expected offset argument");
}
else {
PyErr_Format(state->StructError,
"pack_into expected %zd items for packing (got %zd)",
soself->s_len, (nargs - 2));
}
return NULL;
}
/* Extract a writable memory buffer from the first argument */
if (!PyArg_Parse(args[0], "w*", &buffer))
return NULL;
assert(buffer.len >= 0);
/* Extract the offset from the first argument */
offset = PyNumber_AsSsize_t(args[1], PyExc_IndexError);
if (offset == -1 && PyErr_Occurred()) {
PyBuffer_Release(&buffer);
return NULL;
}
/* Support negative offsets. */
if (offset < 0) {
/* Check that negative offset is low enough to fit data */
if (offset + soself->s_size > 0) {
PyErr_Format(state->StructError,
"no space to pack %zd bytes at offset %zd",
soself->s_size,
offset);
PyBuffer_Release(&buffer);
return NULL;
}
/* Check that negative offset is not crossing buffer boundary */
if (offset + buffer.len < 0) {
PyErr_Format(state->StructError,
"offset %zd out of range for %zd-byte buffer",
offset,
buffer.len);
PyBuffer_Release(&buffer);
return NULL;
}
offset += buffer.len;
}
/* Check boundaries */
if ((buffer.len - offset) < soself->s_size) {
assert(offset >= 0);
assert(soself->s_size >= 0);
PyErr_Format(state->StructError,
"pack_into requires a buffer of at least %zu bytes for "
"packing %zd bytes at offset %zd "
"(actual buffer size is %zd)",
(size_t)soself->s_size + (size_t)offset,
soself->s_size,
offset,
buffer.len);
PyBuffer_Release(&buffer);
return NULL;
}
/* Call the guts */
if (s_pack_internal(soself, args, 2, (char*)buffer.buf + offset, state) != 0) {
PyBuffer_Release(&buffer);
return NULL;
}
PyBuffer_Release(&buffer);
Py_RETURN_NONE;
}
static PyObject *
s_get_format(PyObject *op, void *Py_UNUSED(closure))
{
PyStructObject *self = PyStructObject_CAST(op);
ENSURE_STRUCT_IS_READY(self);
return PyUnicode_FromStringAndSize(PyBytes_AS_STRING(self->s_format),
PyBytes_GET_SIZE(self->s_format));
}
static PyObject *
s_get_size(PyObject *op, void *Py_UNUSED(closure))
{
PyStructObject *self = PyStructObject_CAST(op);
return PyLong_FromSsize_t(self->s_size);
}
PyDoc_STRVAR(s_sizeof__doc__,
"S.__sizeof__() -> size of S in memory, in bytes");
static PyObject *
s_sizeof(PyObject *op, PyObject *Py_UNUSED(dummy))
{
PyStructObject *self = PyStructObject_CAST(op);
ENSURE_STRUCT_IS_READY(self);
size_t size = _PyObject_SIZE(Py_TYPE(self)) + sizeof(formatcode);
for (formatcode *code = self->s_codes; code->fmtdef != NULL; code++) {
size += sizeof(formatcode);
}
return PyLong_FromSize_t(size);
}
static PyObject *
s_repr(PyObject *op)
{
PyStructObject *self = PyStructObject_CAST(op);
ENSURE_STRUCT_IS_READY(self);
PyObject* fmt = PyUnicode_FromStringAndSize(
PyBytes_AS_STRING(self->s_format), PyBytes_GET_SIZE(self->s_format));
if (fmt == NULL) {
return NULL;
}
PyObject* s = PyUnicode_FromFormat("%s(%R)", _PyType_Name(Py_TYPE(self)), fmt);
Py_DECREF(fmt);
return s;
}
/* List of functions */
static struct PyMethodDef s_methods[] = {
STRUCT_ITER_UNPACK_METHODDEF
{"pack", _PyCFunction_CAST(s_pack), METH_FASTCALL, s_pack__doc__},
{"pack_into", _PyCFunction_CAST(s_pack_into), METH_FASTCALL, s_pack_into__doc__},
STRUCT_UNPACK_METHODDEF
STRUCT_UNPACK_FROM_METHODDEF
{"__sizeof__", s_sizeof, METH_NOARGS, s_sizeof__doc__},
{NULL, NULL} /* sentinel */
};
static PyMemberDef s_members[] = {
{"__weaklistoffset__", Py_T_PYSSIZET, offsetof(PyStructObject, weakreflist), Py_READONLY},
{NULL} /* sentinel */
};
static PyGetSetDef s_getsetlist[] = {
{"format", s_get_format, NULL, PyDoc_STR("struct format string"), NULL},
{"size", s_get_size, NULL, PyDoc_STR("struct size in bytes"), NULL},
{NULL} /* sentinel */
};
PyDoc_STRVAR(s__doc__,
"Struct(fmt) --> compiled struct object\n"
"\n"
);
static PyType_Slot PyStructType_slots[] = {
{Py_tp_dealloc, s_dealloc},
{Py_tp_getattro, PyObject_GenericGetAttr},
{Py_tp_setattro, PyObject_GenericSetAttr},
{Py_tp_repr, s_repr},
{Py_tp_doc, (void*)s__doc__},
{Py_tp_traverse, s_traverse},
{Py_tp_clear, s_clear},
{Py_tp_methods, s_methods},
{Py_tp_members, s_members},
{Py_tp_getset, s_getsetlist},
{Py_tp_init, Struct___init__},
{Py_tp_alloc, PyType_GenericAlloc},
{Py_tp_new, s_new},
{Py_tp_free, PyObject_GC_Del},
{0, 0},
};
static PyType_Spec PyStructType_spec = {
"_struct.Struct",
sizeof(PyStructObject),
0,
(Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE | Py_TPFLAGS_IMMUTABLETYPE),
PyStructType_slots
};
/* ---- Standalone functions ---- */
#define MAXCACHE 100
static int
cache_struct_converter(PyObject *module, PyObject *fmt, PyStructObject **ptr)
{
PyObject *s_object;
PyObject *key;
_structmodulestate *state = get_struct_state(module);
if (fmt == NULL) {
Py_SETREF(*ptr, NULL);
return 1;
}
/* Use a str cache key: an equal str and bytes would collide and be
compared, raising BytesWarning under -bb. */
if (PyBytes_Check(fmt)) {
key = PyUnicode_DecodeASCII(PyBytes_AS_STRING(fmt),
PyBytes_GET_SIZE(fmt), "surrogateescape");
if (key == NULL) {
return 0;
}
}
else {
key = Py_NewRef(fmt);
}
if (PyDict_GetItemRef(state->cache, key, &s_object) < 0) {
Py_DECREF(key);
return 0;
}
if (s_object != NULL) {
Py_DECREF(key);
*ptr = PyStructObject_CAST(s_object);
return Py_CLEANUP_SUPPORTED;
}
s_object = PyObject_CallOneArg(state->PyStructType, key);
if (s_object != NULL) {
if (PyDict_GET_SIZE(state->cache) >= MAXCACHE)
PyDict_Clear(state->cache);
/* Attempt to cache the result */
if (PyDict_SetItem(state->cache, key, s_object) == -1)
PyErr_Clear();
Py_DECREF(key);
*ptr = (PyStructObject *)s_object;
return Py_CLEANUP_SUPPORTED;
}
Py_DECREF(key);
return 0;
}
/*[clinic input]
_clearcache
Clear the internal cache.
[clinic start generated code]*/
static PyObject *
_clearcache_impl(PyObject *module)
/*[clinic end generated code: output=ce4fb8a7bf7cb523 input=463eaae04bab3211]*/
{
PyDict_Clear(get_struct_state(module)->cache);
Py_RETURN_NONE;
}
/*[clinic input]
calcsize -> Py_ssize_t
format as s_object: cache_struct
/
Return size in bytes of the struct described by the format string.
[clinic start generated code]*/
static Py_ssize_t
calcsize_impl(PyObject *module, PyStructObject *s_object)
/*[clinic end generated code: output=db7d23d09c6932c4 input=96a6a590c7717ecd]*/
{
return s_object->s_size;
}
PyDoc_STRVAR(pack_doc,
"pack(format, v1, v2, ...) -> bytes\n\
\n\
Return a bytes object containing the values v1, v2, ... packed according\n\
to the format string. See help(struct) for more on format strings.");
static PyObject *
pack(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
{
PyObject *s_object = NULL;
PyObject *format, *result;
if (nargs == 0) {
PyErr_SetString(PyExc_TypeError, "missing format argument");
return NULL;
}
format = args[0];
if (!cache_struct_converter(module, format, (PyStructObject **)&s_object)) {
return NULL;
}
result = s_pack(s_object, args + 1, nargs - 1);
Py_DECREF(s_object);
return result;
}
PyDoc_STRVAR(pack_into_doc,
"pack_into(format, buffer, offset, v1, v2, ...)\n\
\n\
Pack the values v1, v2, ... according to the format string and write\n\
the packed bytes into the writable buffer buf starting at offset. Note\n\
that the offset is a required argument. A negative offset counts from\n\
the end of the buffer. See help(struct) for more on format strings.");
static PyObject *
pack_into(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
{
PyObject *s_object = NULL;
PyObject *format, *result;
if (nargs == 0) {
PyErr_SetString(PyExc_TypeError, "missing format argument");
return NULL;
}
format = args[0];
if (!cache_struct_converter(module, format, (PyStructObject **)&s_object)) {
return NULL;
}
result = s_pack_into(s_object, args + 1, nargs - 1);
Py_DECREF(s_object);
return result;
}
/*[clinic input]
unpack
format as s_object: cache_struct
buffer: Py_buffer
/
Return a tuple containing values unpacked according to the format string.
The buffer's size in bytes must be calcsize(format).
See help(struct) for more on format strings.
[clinic start generated code]*/
static PyObject *
unpack_impl(PyObject *module, PyStructObject *s_object, Py_buffer *buffer)
/*[clinic end generated code: output=48ddd4d88eca8551 input=05fa3b91678da727]*/
{
return Struct_unpack_impl(s_object, buffer);
}
/*[clinic input]
unpack_from
format as s_object: cache_struct
/
buffer: Py_buffer
offset: Py_ssize_t = 0
Return a tuple containing values unpacked according to the format string.
The buffer's size, minus offset, must be at least calcsize(format).
A negative offset counts from the end of the buffer.
See help(struct) for more on format strings.
[clinic start generated code]*/
static PyObject *
unpack_from_impl(PyObject *module, PyStructObject *s_object,
Py_buffer *buffer, Py_ssize_t offset)
/*[clinic end generated code: output=1042631674c6e0d3 input=e383ecb97728be2b]*/
{
return Struct_unpack_from_impl(s_object, buffer, offset);
}
/*[clinic input]
iter_unpack
format as s_object: cache_struct
buffer: object
/
Return an iterator yielding tuples unpacked from the given bytes.
The bytes are unpacked according to the format string, like
a repeated invocation of unpack_from().
Requires that the bytes length be a multiple of the format struct size.
[clinic start generated code]*/
static PyObject *
iter_unpack_impl(PyObject *module, PyStructObject *s_object,
PyObject *buffer)
/*[clinic end generated code: output=0ae50e250d20e74d input=b214a58869a3c98d]*/
{
return Struct_iter_unpack((PyObject*)s_object, buffer);
}
static struct PyMethodDef module_functions[] = {
_CLEARCACHE_METHODDEF
CALCSIZE_METHODDEF
ITER_UNPACK_METHODDEF
{"pack", _PyCFunction_CAST(pack), METH_FASTCALL, pack_doc},
{"pack_into", _PyCFunction_CAST(pack_into), METH_FASTCALL, pack_into_doc},
UNPACK_METHODDEF
UNPACK_FROM_METHODDEF
{NULL, NULL} /* sentinel */
};
/* Module initialization */
PyDoc_STRVAR(module_doc,
"Functions to convert between Python values and C structs.\n\
Python bytes objects are used to hold the data representing the C struct.\n\
The format string (explained below) describes the layout of data\n\
in the C struct.\n\
\n\
The optional first format char indicates byte order, size and alignment:\n\
@: native order, size & alignment (default)\n\
=: native order, std. size & alignment\n\
<: little-endian, std. size & alignment\n\
>: big-endian, std. size & alignment\n\
!: same as >\n\
\n\
The remaining characters indicate types of args and must match exactly;\n\
these can be preceded by a decimal repeat count:\n\
x: pad byte (no data); c: char; b: signed byte; B: unsigned byte;\n\
?: _Bool; h: short; H: unsigned short; i: int; I: unsigned int;\n\
l: long; L: unsigned long; q: long long; Q: unsigned long long;\n\
f: float; d: double; e: half-float;\n\
F: float complex; D: double complex.\n\
Special cases (preceding decimal count indicates length):\n\
s: byte string (array of char); p: Pascal string (with count byte).\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\
Whitespace between formats is ignored.\n\
\n\
The variable struct.error is an exception raised on errors.\n");
static int
_structmodule_traverse(PyObject *module, visitproc visit, void *arg)
{
_structmodulestate *state = get_struct_state(module);
if (state) {
Py_VISIT(state->cache);
Py_VISIT(state->PyStructType);
Py_VISIT(state->unpackiter_type);
Py_VISIT(state->StructError);
}
return 0;
}
static int
_structmodule_clear(PyObject *module)
{
_structmodulestate *state = get_struct_state(module);
if (state) {
Py_CLEAR(state->cache);
Py_CLEAR(state->PyStructType);
Py_CLEAR(state->unpackiter_type);
Py_CLEAR(state->StructError);
}
return 0;
}
static void
_structmodule_free(void *module)
{
(void)_structmodule_clear((PyObject *)module);
}
static int
_structmodule_exec(PyObject *m)
{
_structmodulestate *state = get_struct_state(m);
state->cache = PyDict_New();
if (state->cache == NULL) {
return -1;
}
state->PyStructType = PyType_FromModuleAndSpec(
m, &PyStructType_spec, NULL);
if (state->PyStructType == NULL) {
return -1;
}
if (PyModule_AddType(m, (PyTypeObject *)state->PyStructType) < 0) {
return -1;
}
state->unpackiter_type = PyType_FromModuleAndSpec(
m, &unpackiter_type_spec, NULL);
if (state->unpackiter_type == NULL) {
return -1;
}
/* init cannot fail */
(void)_PyOnceFlag_CallOnce(&endian_tables_init_once, init_endian_tables, NULL);
/* Add some symbolic constants to the module */
state->StructError = PyErr_NewException("struct.error", NULL, NULL);
if (state->StructError == NULL) {
return -1;
}
if (PyModule_AddObjectRef(m, "error", state->StructError) < 0) {
return -1;
}
return 0;
}
static PyModuleDef_Slot _structmodule_slots[] = {
{Py_mod_exec, _structmodule_exec},
{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
{Py_mod_gil, Py_MOD_GIL_NOT_USED},
{0, NULL}
};
static struct PyModuleDef _structmodule = {
PyModuleDef_HEAD_INIT,
.m_name = "_struct",
.m_doc = module_doc,
.m_size = sizeof(_structmodulestate),
.m_methods = module_functions,
.m_slots = _structmodule_slots,
.m_traverse = _structmodule_traverse,
.m_clear = _structmodule_clear,
.m_free = _structmodule_free,
};
PyMODINIT_FUNC
PyInit__struct(void)
{
return PyModuleDef_Init(&_structmodule);
}
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