Staging
v0.5.1
Revision 123f6c4914827c4ced65d032fab74de62db31cd6 authored by Miss Islington (bot) on 14 August 2019, 21:47:43 UTC, committed by GitHub on 14 August 2019, 21:47:43 UTC

FreeBSD implementation of poll(2) restricts the timeout argument to be
either zero, or positive, or equal to INFTIM (-1).

Unless otherwise overridden, socket timeout defaults to -1. This value
is then converted to milliseconds (-1000) and used as argument to the
poll syscall. poll returns EINVAL (22), and the connection fails.

This bug was discovered during the EINTR handling testing, and the
reproduction code can be found in
https://bugs.python.org/issue23618 (see connect_eintr.py,
attached). On GNU/Linux, the example runs as expected.

This change is trivial:
If the supplied timeout value is negative, truncate it to -1.
(cherry picked from commit 28146206578ebe1b84b48e6f255738a227058c04)

Co-authored-by: Artem Khramov <akhramov@pm.me>
1 parent 557802d
Raw File
getargs.c

/* New getargs implementation */

#include "Python.h"
#include "pycore_tupleobject.h"

#include <ctype.h>
#include <float.h>


#ifdef __cplusplus
extern "C" {
#endif
int PyArg_Parse(PyObject *, const char *, ...);
int PyArg_ParseTuple(PyObject *, const char *, ...);
int PyArg_VaParse(PyObject *, const char *, va_list);

int PyArg_ParseTupleAndKeywords(PyObject *, PyObject *,
                                const char *, char **, ...);
int PyArg_VaParseTupleAndKeywords(PyObject *, PyObject *,
                                const char *, char **, va_list);

int _PyArg_ParseTupleAndKeywordsFast(PyObject *, PyObject *,
                                            struct _PyArg_Parser *, ...);
int _PyArg_VaParseTupleAndKeywordsFast(PyObject *, PyObject *,
                                            struct _PyArg_Parser *, va_list);

#ifdef HAVE_DECLSPEC_DLL
/* Export functions */
PyAPI_FUNC(int) _PyArg_Parse_SizeT(PyObject *, const char *, ...);
PyAPI_FUNC(int) _PyArg_ParseStack_SizeT(PyObject *const *args, Py_ssize_t nargs,
                                        const char *format, ...);
PyAPI_FUNC(int) _PyArg_ParseStackAndKeywords_SizeT(PyObject *const *args, Py_ssize_t nargs,
                                        PyObject *kwnames,
                                        struct _PyArg_Parser *parser, ...);
PyAPI_FUNC(int) _PyArg_ParseTuple_SizeT(PyObject *, const char *, ...);
PyAPI_FUNC(int) _PyArg_ParseTupleAndKeywords_SizeT(PyObject *, PyObject *,
                                                  const char *, char **, ...);
PyAPI_FUNC(PyObject *) _Py_BuildValue_SizeT(const char *, ...);
PyAPI_FUNC(int) _PyArg_VaParse_SizeT(PyObject *, const char *, va_list);
PyAPI_FUNC(int) _PyArg_VaParseTupleAndKeywords_SizeT(PyObject *, PyObject *,
                                              const char *, char **, va_list);

PyAPI_FUNC(int) _PyArg_ParseTupleAndKeywordsFast_SizeT(PyObject *, PyObject *,
                                            struct _PyArg_Parser *, ...);
PyAPI_FUNC(int) _PyArg_VaParseTupleAndKeywordsFast_SizeT(PyObject *, PyObject *,
                                            struct _PyArg_Parser *, va_list);
#endif

#define FLAG_COMPAT 1
#define FLAG_SIZE_T 2

typedef int (*destr_t)(PyObject *, void *);


/* Keep track of "objects" that have been allocated or initialized and
   which will need to be deallocated or cleaned up somehow if overall
   parsing fails.
*/
typedef struct {
  void *item;
  destr_t destructor;
} freelistentry_t;

typedef struct {
  freelistentry_t *entries;
  int first_available;
  int entries_malloced;
} freelist_t;

#define STATIC_FREELIST_ENTRIES 8

/* Forward */
static int vgetargs1_impl(PyObject *args, PyObject *const *stack, Py_ssize_t nargs,
                          const char *format, va_list *p_va, int flags);
static int vgetargs1(PyObject *, const char *, va_list *, int);
static void seterror(Py_ssize_t, const char *, int *, const char *, const char *);
static const char *convertitem(PyObject *, const char **, va_list *, int, int *,
                               char *, size_t, freelist_t *);
static const char *converttuple(PyObject *, const char **, va_list *, int,
                                int *, char *, size_t, int, freelist_t *);
static const char *convertsimple(PyObject *, const char **, va_list *, int,
                                 char *, size_t, freelist_t *);
static Py_ssize_t convertbuffer(PyObject *, const void **p, const char **);
static int getbuffer(PyObject *, Py_buffer *, const char**);

static int vgetargskeywords(PyObject *, PyObject *,
                            const char *, char **, va_list *, int);
static int vgetargskeywordsfast(PyObject *, PyObject *,
                            struct _PyArg_Parser *, va_list *, int);
static int vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
                          PyObject *keywords, PyObject *kwnames,
                          struct _PyArg_Parser *parser,
                          va_list *p_va, int flags);
static const char *skipitem(const char **, va_list *, int);

int
PyArg_Parse(PyObject *args, const char *format, ...)
{
    int retval;
    va_list va;

    va_start(va, format);
    retval = vgetargs1(args, format, &va, FLAG_COMPAT);
    va_end(va);
    return retval;
}

int
_PyArg_Parse_SizeT(PyObject *args, const char *format, ...)
{
    int retval;
    va_list va;

    va_start(va, format);
    retval = vgetargs1(args, format, &va, FLAG_COMPAT|FLAG_SIZE_T);
    va_end(va);
    return retval;
}


int
PyArg_ParseTuple(PyObject *args, const char *format, ...)
{
    int retval;
    va_list va;

    va_start(va, format);
    retval = vgetargs1(args, format, &va, 0);
    va_end(va);
    return retval;
}

int
_PyArg_ParseTuple_SizeT(PyObject *args, const char *format, ...)
{
    int retval;
    va_list va;

    va_start(va, format);
    retval = vgetargs1(args, format, &va, FLAG_SIZE_T);
    va_end(va);
    return retval;
}


int
_PyArg_ParseStack(PyObject *const *args, Py_ssize_t nargs, const char *format, ...)
{
    int retval;
    va_list va;

    va_start(va, format);
    retval = vgetargs1_impl(NULL, args, nargs, format, &va, 0);
    va_end(va);
    return retval;
}

int
_PyArg_ParseStack_SizeT(PyObject *const *args, Py_ssize_t nargs, const char *format, ...)
{
    int retval;
    va_list va;

    va_start(va, format);
    retval = vgetargs1_impl(NULL, args, nargs, format, &va, FLAG_SIZE_T);
    va_end(va);
    return retval;
}


int
PyArg_VaParse(PyObject *args, const char *format, va_list va)
{
    va_list lva;
    int retval;

    va_copy(lva, va);

    retval = vgetargs1(args, format, &lva, 0);
    va_end(lva);
    return retval;
}

int
_PyArg_VaParse_SizeT(PyObject *args, const char *format, va_list va)
{
    va_list lva;
    int retval;

    va_copy(lva, va);

    retval = vgetargs1(args, format, &lva, FLAG_SIZE_T);
    va_end(lva);
    return retval;
}


/* Handle cleanup of allocated memory in case of exception */

static int
cleanup_ptr(PyObject *self, void *ptr)
{
    if (ptr) {
        PyMem_FREE(ptr);
    }
    return 0;
}

static int
cleanup_buffer(PyObject *self, void *ptr)
{
    Py_buffer *buf = (Py_buffer *)ptr;
    if (buf) {
        PyBuffer_Release(buf);
    }
    return 0;
}

static int
addcleanup(void *ptr, freelist_t *freelist, destr_t destructor)
{
    int index;

    index = freelist->first_available;
    freelist->first_available += 1;

    freelist->entries[index].item = ptr;
    freelist->entries[index].destructor = destructor;

    return 0;
}

static int
cleanreturn(int retval, freelist_t *freelist)
{
    int index;

    if (retval == 0) {
      /* A failure occurred, therefore execute all of the cleanup
         functions.
      */
      for (index = 0; index < freelist->first_available; ++index) {
          freelist->entries[index].destructor(NULL,
                                              freelist->entries[index].item);
      }
    }
    if (freelist->entries_malloced)
        PyMem_FREE(freelist->entries);
    return retval;
}


static int
vgetargs1_impl(PyObject *compat_args, PyObject *const *stack, Py_ssize_t nargs, const char *format,
               va_list *p_va, int flags)
{
    char msgbuf[256];
    int levels[32];
    const char *fname = NULL;
    const char *message = NULL;
    int min = -1;
    int max = 0;
    int level = 0;
    int endfmt = 0;
    const char *formatsave = format;
    Py_ssize_t i;
    const char *msg;
    int compat = flags & FLAG_COMPAT;
    freelistentry_t static_entries[STATIC_FREELIST_ENTRIES];
    freelist_t freelist;

    assert(nargs == 0 || stack != NULL);

    freelist.entries = static_entries;
    freelist.first_available = 0;
    freelist.entries_malloced = 0;

    flags = flags & ~FLAG_COMPAT;

    while (endfmt == 0) {
        int c = *format++;
        switch (c) {
        case '(':
            if (level == 0)
                max++;
            level++;
            if (level >= 30)
                Py_FatalError("too many tuple nesting levels "
                              "in argument format string");
            break;
        case ')':
            if (level == 0)
                Py_FatalError("excess ')' in getargs format");
            else
                level--;
            break;
        case '\0':
            endfmt = 1;
            break;
        case ':':
            fname = format;
            endfmt = 1;
            break;
        case ';':
            message = format;
            endfmt = 1;
            break;
        case '|':
            if (level == 0)
                min = max;
            break;
        default:
            if (level == 0) {
                if (Py_ISALPHA(Py_CHARMASK(c)))
                    if (c != 'e') /* skip encoded */
                        max++;
            }
            break;
        }
    }

    if (level != 0)
        Py_FatalError(/* '(' */ "missing ')' in getargs format");

    if (min < 0)
        min = max;

    format = formatsave;

    if (max > STATIC_FREELIST_ENTRIES) {
        freelist.entries = PyMem_NEW(freelistentry_t, max);
        if (freelist.entries == NULL) {
            PyErr_NoMemory();
            return 0;
        }
        freelist.entries_malloced = 1;
    }

    if (compat) {
        if (max == 0) {
            if (compat_args == NULL)
                return 1;
            PyErr_Format(PyExc_TypeError,
                         "%.200s%s takes no arguments",
                         fname==NULL ? "function" : fname,
                         fname==NULL ? "" : "()");
            return cleanreturn(0, &freelist);
        }
        else if (min == 1 && max == 1) {
            if (compat_args == NULL) {
                PyErr_Format(PyExc_TypeError,
                             "%.200s%s takes at least one argument",
                             fname==NULL ? "function" : fname,
                             fname==NULL ? "" : "()");
                return cleanreturn(0, &freelist);
            }
            msg = convertitem(compat_args, &format, p_va, flags, levels,
                              msgbuf, sizeof(msgbuf), &freelist);
            if (msg == NULL)
                return cleanreturn(1, &freelist);
            seterror(levels[0], msg, levels+1, fname, message);
            return cleanreturn(0, &freelist);
        }
        else {
            PyErr_SetString(PyExc_SystemError,
                "old style getargs format uses new features");
            return cleanreturn(0, &freelist);
        }
    }

    if (nargs < min || max < nargs) {
        if (message == NULL)
            PyErr_Format(PyExc_TypeError,
                         "%.150s%s takes %s %d argument%s (%zd given)",
                         fname==NULL ? "function" : fname,
                         fname==NULL ? "" : "()",
                         min==max ? "exactly"
                         : nargs < min ? "at least" : "at most",
                         nargs < min ? min : max,
                         (nargs < min ? min : max) == 1 ? "" : "s",
                         nargs);
        else
            PyErr_SetString(PyExc_TypeError, message);
        return cleanreturn(0, &freelist);
    }

    for (i = 0; i < nargs; i++) {
        if (*format == '|')
            format++;
        msg = convertitem(stack[i], &format, p_va,
                          flags, levels, msgbuf,
                          sizeof(msgbuf), &freelist);
        if (msg) {
            seterror(i+1, msg, levels, fname, message);
            return cleanreturn(0, &freelist);
        }
    }

    if (*format != '\0' && !Py_ISALPHA(Py_CHARMASK(*format)) &&
        *format != '(' &&
        *format != '|' && *format != ':' && *format != ';') {
        PyErr_Format(PyExc_SystemError,
                     "bad format string: %.200s", formatsave);
        return cleanreturn(0, &freelist);
    }

    return cleanreturn(1, &freelist);
}

static int
vgetargs1(PyObject *args, const char *format, va_list *p_va, int flags)
{
    PyObject **stack;
    Py_ssize_t nargs;

    if (!(flags & FLAG_COMPAT)) {
        assert(args != NULL);

        if (!PyTuple_Check(args)) {
            PyErr_SetString(PyExc_SystemError,
                "new style getargs format but argument is not a tuple");
            return 0;
        }

        stack = _PyTuple_ITEMS(args);
        nargs = PyTuple_GET_SIZE(args);
    }
    else {
        stack = NULL;
        nargs = 0;
    }

    return vgetargs1_impl(args, stack, nargs, format, p_va, flags);
}


static void
seterror(Py_ssize_t iarg, const char *msg, int *levels, const char *fname,
         const char *message)
{
    char buf[512];
    int i;
    char *p = buf;

    if (PyErr_Occurred())
        return;
    else if (message == NULL) {
        if (fname != NULL) {
            PyOS_snprintf(p, sizeof(buf), "%.200s() ", fname);
            p += strlen(p);
        }
        if (iarg != 0) {
            PyOS_snprintf(p, sizeof(buf) - (p - buf),
                          "argument %" PY_FORMAT_SIZE_T "d", iarg);
            i = 0;
            p += strlen(p);
            while (i < 32 && levels[i] > 0 && (int)(p-buf) < 220) {
                PyOS_snprintf(p, sizeof(buf) - (p - buf),
                              ", item %d", levels[i]-1);
                p += strlen(p);
                i++;
            }
        }
        else {
            PyOS_snprintf(p, sizeof(buf) - (p - buf), "argument");
            p += strlen(p);
        }
        PyOS_snprintf(p, sizeof(buf) - (p - buf), " %.256s", msg);
        message = buf;
    }
    if (msg[0] == '(') {
        PyErr_SetString(PyExc_SystemError, message);
    }
    else {
        PyErr_SetString(PyExc_TypeError, message);
    }
}


/* Convert a tuple argument.
   On entry, *p_format points to the character _after_ the opening '('.
   On successful exit, *p_format points to the closing ')'.
   If successful:
      *p_format and *p_va are updated,
      *levels and *msgbuf are untouched,
      and NULL is returned.
   If the argument is invalid:
      *p_format is unchanged,
      *p_va is undefined,
      *levels is a 0-terminated list of item numbers,
      *msgbuf contains an error message, whose format is:
     "must be <typename1>, not <typename2>", where:
        <typename1> is the name of the expected type, and
        <typename2> is the name of the actual type,
      and msgbuf is returned.
*/

static const char *
converttuple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
             int *levels, char *msgbuf, size_t bufsize, int toplevel,
             freelist_t *freelist)
{
    int level = 0;
    int n = 0;
    const char *format = *p_format;
    int i;
    Py_ssize_t len;

    for (;;) {
        int c = *format++;
        if (c == '(') {
            if (level == 0)
                n++;
            level++;
        }
        else if (c == ')') {
            if (level == 0)
                break;
            level--;
        }
        else if (c == ':' || c == ';' || c == '\0')
            break;
        else if (level == 0 && Py_ISALPHA(Py_CHARMASK(c)))
            n++;
    }

    if (!PySequence_Check(arg) || PyBytes_Check(arg)) {
        levels[0] = 0;
        PyOS_snprintf(msgbuf, bufsize,
                      toplevel ? "expected %d arguments, not %.50s" :
                      "must be %d-item sequence, not %.50s",
                  n,
                  arg == Py_None ? "None" : arg->ob_type->tp_name);
        return msgbuf;
    }

    len = PySequence_Size(arg);
    if (len != n) {
        levels[0] = 0;
        if (toplevel) {
            PyOS_snprintf(msgbuf, bufsize,
                          "expected %d argument%s, not %" PY_FORMAT_SIZE_T "d",
                          n,
                          n == 1 ? "" : "s",
                          len);
        }
        else {
            PyOS_snprintf(msgbuf, bufsize,
                          "must be sequence of length %d, "
                          "not %" PY_FORMAT_SIZE_T "d",
                          n, len);
        }
        return msgbuf;
    }

    format = *p_format;
    for (i = 0; i < n; i++) {
        const char *msg;
        PyObject *item;
        item = PySequence_GetItem(arg, i);
        if (item == NULL) {
            PyErr_Clear();
            levels[0] = i+1;
            levels[1] = 0;
            strncpy(msgbuf, "is not retrievable", bufsize);
            return msgbuf;
        }
        msg = convertitem(item, &format, p_va, flags, levels+1,
                          msgbuf, bufsize, freelist);
        /* PySequence_GetItem calls tp->sq_item, which INCREFs */
        Py_XDECREF(item);
        if (msg != NULL) {
            levels[0] = i+1;
            return msg;
        }
    }

    *p_format = format;
    return NULL;
}


/* Convert a single item. */

static const char *
convertitem(PyObject *arg, const char **p_format, va_list *p_va, int flags,
            int *levels, char *msgbuf, size_t bufsize, freelist_t *freelist)
{
    const char *msg;
    const char *format = *p_format;

    if (*format == '(' /* ')' */) {
        format++;
        msg = converttuple(arg, &format, p_va, flags, levels, msgbuf,
                           bufsize, 0, freelist);
        if (msg == NULL)
            format++;
    }
    else {
        msg = convertsimple(arg, &format, p_va, flags,
                            msgbuf, bufsize, freelist);
        if (msg != NULL)
            levels[0] = 0;
    }
    if (msg == NULL)
        *p_format = format;
    return msg;
}



/* Format an error message generated by convertsimple(). */

void
_PyArg_BadArgument(const char *fname, int iarg,
                   const char *expected, PyObject *arg)
{
    if (iarg) {
        PyErr_Format(PyExc_TypeError,
                     "%.200s() argument %d must be %.50s, not %.50s",
                     fname, iarg, expected,
                     arg == Py_None ? "None" : arg->ob_type->tp_name);
    }
    else {
        PyErr_Format(PyExc_TypeError,
                     "%.200s() argument must be %.50s, not %.50s",
                     fname, expected,
                     arg == Py_None ? "None" : arg->ob_type->tp_name);
    }
}

static const char *
converterr(const char *expected, PyObject *arg, char *msgbuf, size_t bufsize)
{
    assert(expected != NULL);
    assert(arg != NULL);
    if (expected[0] == '(') {
        PyOS_snprintf(msgbuf, bufsize,
                      "%.100s", expected);
    }
    else {
        PyOS_snprintf(msgbuf, bufsize,
                      "must be %.50s, not %.50s", expected,
                      arg == Py_None ? "None" : arg->ob_type->tp_name);
    }
    return msgbuf;
}

#define CONV_UNICODE "(unicode conversion error)"

/* Explicitly check for float arguments when integers are expected.
   Return 1 for error, 0 if ok.
   XXX Should be removed after the end of the deprecation period in
   _PyLong_FromNbIndexOrNbInt. */
static int
float_argument_error(PyObject *arg)
{
    if (PyFloat_Check(arg)) {
        PyErr_SetString(PyExc_TypeError,
                        "integer argument expected, got float" );
        return 1;
    }
    else
        return 0;
}

/* Convert a non-tuple argument.  Return NULL if conversion went OK,
   or a string with a message describing the failure.  The message is
   formatted as "must be <desired type>, not <actual type>".
   When failing, an exception may or may not have been raised.
   Don't call if a tuple is expected.

   When you add new format codes, please don't forget poor skipitem() below.
*/

static const char *
convertsimple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
              char *msgbuf, size_t bufsize, freelist_t *freelist)
{
    /* For # codes */
#define FETCH_SIZE      int *q=NULL;Py_ssize_t *q2=NULL;\
    if (flags & FLAG_SIZE_T) q2=va_arg(*p_va, Py_ssize_t*); \
    else { \
        if (PyErr_WarnEx(PyExc_DeprecationWarning, \
                    "PY_SSIZE_T_CLEAN will be required for '#' formats", 1)) { \
            return NULL; \
        } \
        q=va_arg(*p_va, int*); \
    }
#define STORE_SIZE(s)   \
    if (flags & FLAG_SIZE_T) \
        *q2=s; \
    else { \
        if (INT_MAX < s) { \
            PyErr_SetString(PyExc_OverflowError, \
                "size does not fit in an int"); \
            return converterr("", arg, msgbuf, bufsize); \
        } \
        *q = (int)s; \
    }
#define BUFFER_LEN      ((flags & FLAG_SIZE_T) ? *q2:*q)
#define RETURN_ERR_OCCURRED return msgbuf

    const char *format = *p_format;
    char c = *format++;
    const char *sarg;

    switch (c) {

    case 'b': { /* unsigned byte -- very short int */
        char *p = va_arg(*p_va, char *);
        long ival;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        ival = PyLong_AsLong(arg);
        if (ival == -1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else if (ival < 0) {
            PyErr_SetString(PyExc_OverflowError,
                            "unsigned byte integer is less than minimum");
            RETURN_ERR_OCCURRED;
        }
        else if (ival > UCHAR_MAX) {
            PyErr_SetString(PyExc_OverflowError,
                            "unsigned byte integer is greater than maximum");
            RETURN_ERR_OCCURRED;
        }
        else
            *p = (unsigned char) ival;
        break;
    }

    case 'B': {/* byte sized bitfield - both signed and unsigned
                  values allowed */
        char *p = va_arg(*p_va, char *);
        long ival;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        ival = PyLong_AsUnsignedLongMask(arg);
        if (ival == -1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else
            *p = (unsigned char) ival;
        break;
    }

    case 'h': {/* signed short int */
        short *p = va_arg(*p_va, short *);
        long ival;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        ival = PyLong_AsLong(arg);
        if (ival == -1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else if (ival < SHRT_MIN) {
            PyErr_SetString(PyExc_OverflowError,
                            "signed short integer is less than minimum");
            RETURN_ERR_OCCURRED;
        }
        else if (ival > SHRT_MAX) {
            PyErr_SetString(PyExc_OverflowError,
                            "signed short integer is greater than maximum");
            RETURN_ERR_OCCURRED;
        }
        else
            *p = (short) ival;
        break;
    }

    case 'H': { /* short int sized bitfield, both signed and
                   unsigned allowed */
        unsigned short *p = va_arg(*p_va, unsigned short *);
        long ival;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        ival = PyLong_AsUnsignedLongMask(arg);
        if (ival == -1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else
            *p = (unsigned short) ival;
        break;
    }

    case 'i': {/* signed int */
        int *p = va_arg(*p_va, int *);
        long ival;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        ival = PyLong_AsLong(arg);
        if (ival == -1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else if (ival > INT_MAX) {
            PyErr_SetString(PyExc_OverflowError,
                            "signed integer is greater than maximum");
            RETURN_ERR_OCCURRED;
        }
        else if (ival < INT_MIN) {
            PyErr_SetString(PyExc_OverflowError,
                            "signed integer is less than minimum");
            RETURN_ERR_OCCURRED;
        }
        else
            *p = ival;
        break;
    }

    case 'I': { /* int sized bitfield, both signed and
                   unsigned allowed */
        unsigned int *p = va_arg(*p_va, unsigned int *);
        unsigned int ival;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        ival = (unsigned int)PyLong_AsUnsignedLongMask(arg);
        if (ival == (unsigned int)-1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else
            *p = ival;
        break;
    }

    case 'n': /* Py_ssize_t */
    {
        PyObject *iobj;
        Py_ssize_t *p = va_arg(*p_va, Py_ssize_t *);
        Py_ssize_t ival = -1;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        iobj = PyNumber_Index(arg);
        if (iobj != NULL) {
            ival = PyLong_AsSsize_t(iobj);
            Py_DECREF(iobj);
        }
        if (ival == -1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        *p = ival;
        break;
    }
    case 'l': {/* long int */
        long *p = va_arg(*p_va, long *);
        long ival;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        ival = PyLong_AsLong(arg);
        if (ival == -1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else
            *p = ival;
        break;
    }

    case 'k': { /* long sized bitfield */
        unsigned long *p = va_arg(*p_va, unsigned long *);
        unsigned long ival;
        if (PyLong_Check(arg))
            ival = PyLong_AsUnsignedLongMask(arg);
        else
            return converterr("int", arg, msgbuf, bufsize);
        *p = ival;
        break;
    }

    case 'L': {/* long long */
        long long *p = va_arg( *p_va, long long * );
        long long ival;
        if (float_argument_error(arg))
            RETURN_ERR_OCCURRED;
        ival = PyLong_AsLongLong(arg);
        if (ival == (long long)-1 && PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else
            *p = ival;
        break;
    }

    case 'K': { /* long long sized bitfield */
        unsigned long long *p = va_arg(*p_va, unsigned long long *);
        unsigned long long ival;
        if (PyLong_Check(arg))
            ival = PyLong_AsUnsignedLongLongMask(arg);
        else
            return converterr("int", arg, msgbuf, bufsize);
        *p = ival;
        break;
    }

    case 'f': {/* float */
        float *p = va_arg(*p_va, float *);
        double dval = PyFloat_AsDouble(arg);
        if (PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else
            *p = (float) dval;
        break;
    }

    case 'd': {/* double */
        double *p = va_arg(*p_va, double *);
        double dval = PyFloat_AsDouble(arg);
        if (PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else
            *p = dval;
        break;
    }

    case 'D': {/* complex double */
        Py_complex *p = va_arg(*p_va, Py_complex *);
        Py_complex cval;
        cval = PyComplex_AsCComplex(arg);
        if (PyErr_Occurred())
            RETURN_ERR_OCCURRED;
        else
            *p = cval;
        break;
    }

    case 'c': {/* char */
        char *p = va_arg(*p_va, char *);
        if (PyBytes_Check(arg) && PyBytes_Size(arg) == 1)
            *p = PyBytes_AS_STRING(arg)[0];
        else if (PyByteArray_Check(arg) && PyByteArray_Size(arg) == 1)
            *p = PyByteArray_AS_STRING(arg)[0];
        else
            return converterr("a byte string of length 1", arg, msgbuf, bufsize);
        break;
    }

    case 'C': {/* unicode char */
        int *p = va_arg(*p_va, int *);
        int kind;
        void *data;

        if (!PyUnicode_Check(arg))
            return converterr("a unicode character", arg, msgbuf, bufsize);

        if (PyUnicode_READY(arg))
            RETURN_ERR_OCCURRED;

        if (PyUnicode_GET_LENGTH(arg) != 1)
            return converterr("a unicode character", arg, msgbuf, bufsize);

        kind = PyUnicode_KIND(arg);
        data = PyUnicode_DATA(arg);
        *p = PyUnicode_READ(kind, data, 0);
        break;
    }

    case 'p': {/* boolean *p*redicate */
        int *p = va_arg(*p_va, int *);
        int val = PyObject_IsTrue(arg);
        if (val > 0)
            *p = 1;
        else if (val == 0)
            *p = 0;
        else
            RETURN_ERR_OCCURRED;
        break;
    }

    /* XXX WAAAAH!  's', 'y', 'z', 'u', 'Z', 'e', 'w' codes all
       need to be cleaned up! */

    case 'y': {/* any bytes-like object */
        void **p = (void **)va_arg(*p_va, char **);
        const char *buf;
        Py_ssize_t count;
        if (*format == '*') {
            if (getbuffer(arg, (Py_buffer*)p, &buf) < 0)
                return converterr(buf, arg, msgbuf, bufsize);
            format++;
            if (addcleanup(p, freelist, cleanup_buffer)) {
                return converterr(
                    "(cleanup problem)",
                    arg, msgbuf, bufsize);
            }
            break;
        }
        count = convertbuffer(arg, (const void **)p, &buf);
        if (count < 0)
            return converterr(buf, arg, msgbuf, bufsize);
        if (*format == '#') {
            FETCH_SIZE;
            STORE_SIZE(count);
            format++;
        } else {
            if (strlen(*p) != (size_t)count) {
                PyErr_SetString(PyExc_ValueError, "embedded null byte");
                RETURN_ERR_OCCURRED;
            }
        }
        break;
    }

    case 's': /* text string or bytes-like object */
    case 'z': /* text string, bytes-like object or None */
    {
        if (*format == '*') {
            /* "s*" or "z*" */
            Py_buffer *p = (Py_buffer *)va_arg(*p_va, Py_buffer *);

            if (c == 'z' && arg == Py_None)
                PyBuffer_FillInfo(p, NULL, NULL, 0, 1, 0);
            else if (PyUnicode_Check(arg)) {
                Py_ssize_t len;
                sarg = PyUnicode_AsUTF8AndSize(arg, &len);
                if (sarg == NULL)
                    return converterr(CONV_UNICODE,
                                      arg, msgbuf, bufsize);
                PyBuffer_FillInfo(p, arg, (void *)sarg, len, 1, 0);
            }
            else { /* any bytes-like object */
                const char *buf;
                if (getbuffer(arg, p, &buf) < 0)
                    return converterr(buf, arg, msgbuf, bufsize);
            }
            if (addcleanup(p, freelist, cleanup_buffer)) {
                return converterr(
                    "(cleanup problem)",
                    arg, msgbuf, bufsize);
            }
            format++;
        } else if (*format == '#') { /* a string or read-only bytes-like object */
            /* "s#" or "z#" */
            const void **p = (const void **)va_arg(*p_va, const char **);
            FETCH_SIZE;

            if (c == 'z' && arg == Py_None) {
                *p = NULL;
                STORE_SIZE(0);
            }
            else if (PyUnicode_Check(arg)) {
                Py_ssize_t len;
                sarg = PyUnicode_AsUTF8AndSize(arg, &len);
                if (sarg == NULL)
                    return converterr(CONV_UNICODE,
                                      arg, msgbuf, bufsize);
                *p = sarg;
                STORE_SIZE(len);
            }
            else { /* read-only bytes-like object */
                /* XXX Really? */
                const char *buf;
                Py_ssize_t count = convertbuffer(arg, p, &buf);
                if (count < 0)
                    return converterr(buf, arg, msgbuf, bufsize);
                STORE_SIZE(count);
            }
            format++;
        } else {
            /* "s" or "z" */
            const char **p = va_arg(*p_va, const char **);
            Py_ssize_t len;
            sarg = NULL;

            if (c == 'z' && arg == Py_None)
                *p = NULL;
            else if (PyUnicode_Check(arg)) {
                sarg = PyUnicode_AsUTF8AndSize(arg, &len);
                if (sarg == NULL)
                    return converterr(CONV_UNICODE,
                                      arg, msgbuf, bufsize);
                if (strlen(sarg) != (size_t)len) {
                    PyErr_SetString(PyExc_ValueError, "embedded null character");
                    RETURN_ERR_OCCURRED;
                }
                *p = sarg;
            }
            else
                return converterr(c == 'z' ? "str or None" : "str",
                                  arg, msgbuf, bufsize);
        }
        break;
    }

    case 'u': /* raw unicode buffer (Py_UNICODE *) */
    case 'Z': /* raw unicode buffer or None */
    {
        Py_UNICODE **p = va_arg(*p_va, Py_UNICODE **);

        if (*format == '#') {
            /* "u#" or "Z#" */
            FETCH_SIZE;

            if (c == 'Z' && arg == Py_None) {
                *p = NULL;
                STORE_SIZE(0);
            }
            else if (PyUnicode_Check(arg)) {
                Py_ssize_t len;
                *p = PyUnicode_AsUnicodeAndSize(arg, &len);
                if (*p == NULL)
                    RETURN_ERR_OCCURRED;
                STORE_SIZE(len);
            }
            else
                return converterr(c == 'Z' ? "str or None" : "str",
                                  arg, msgbuf, bufsize);
            format++;
        } else {
            /* "u" or "Z" */
            if (c == 'Z' && arg == Py_None)
                *p = NULL;
            else if (PyUnicode_Check(arg)) {
                Py_ssize_t len;
                *p = PyUnicode_AsUnicodeAndSize(arg, &len);
                if (*p == NULL)
                    RETURN_ERR_OCCURRED;
                if (wcslen(*p) != (size_t)len) {
                    PyErr_SetString(PyExc_ValueError, "embedded null character");
                    RETURN_ERR_OCCURRED;
                }
            } else
                return converterr(c == 'Z' ? "str or None" : "str",
                                  arg, msgbuf, bufsize);
        }
        break;
    }

    case 'e': {/* encoded string */
        char **buffer;
        const char *encoding;
        PyObject *s;
        int recode_strings;
        Py_ssize_t size;
        const char *ptr;

        /* Get 'e' parameter: the encoding name */
        encoding = (const char *)va_arg(*p_va, const char *);
        if (encoding == NULL)
            encoding = PyUnicode_GetDefaultEncoding();

        /* Get output buffer parameter:
           's' (recode all objects via Unicode) or
           't' (only recode non-string objects)
        */
        if (*format == 's')
            recode_strings = 1;
        else if (*format == 't')
            recode_strings = 0;
        else
            return converterr(
                "(unknown parser marker combination)",
                arg, msgbuf, bufsize);
        buffer = (char **)va_arg(*p_va, char **);
        format++;
        if (buffer == NULL)
            return converterr("(buffer is NULL)",
                              arg, msgbuf, bufsize);

        /* Encode object */
        if (!recode_strings &&
            (PyBytes_Check(arg) || PyByteArray_Check(arg))) {
            s = arg;
            Py_INCREF(s);
            if (PyBytes_Check(arg)) {
                size = PyBytes_GET_SIZE(s);
                ptr = PyBytes_AS_STRING(s);
            }
            else {
                size = PyByteArray_GET_SIZE(s);
                ptr = PyByteArray_AS_STRING(s);
            }
        }
        else if (PyUnicode_Check(arg)) {
            /* Encode object; use default error handling */
            s = PyUnicode_AsEncodedString(arg,
                                          encoding,
                                          NULL);
            if (s == NULL)
                return converterr("(encoding failed)",
                                  arg, msgbuf, bufsize);
            assert(PyBytes_Check(s));
            size = PyBytes_GET_SIZE(s);
            ptr = PyBytes_AS_STRING(s);
            if (ptr == NULL)
                ptr = "";
        }
        else {
            return converterr(
                recode_strings ? "str" : "str, bytes or bytearray",
                arg, msgbuf, bufsize);
        }

        /* Write output; output is guaranteed to be 0-terminated */
        if (*format == '#') {
            /* Using buffer length parameter '#':

               - if *buffer is NULL, a new buffer of the
               needed size is allocated and the data
               copied into it; *buffer is updated to point
               to the new buffer; the caller is
               responsible for PyMem_Free()ing it after
               usage

               - if *buffer is not NULL, the data is
               copied to *buffer; *buffer_len has to be
               set to the size of the buffer on input;
               buffer overflow is signalled with an error;
               buffer has to provide enough room for the
               encoded string plus the trailing 0-byte

               - in both cases, *buffer_len is updated to
               the size of the buffer /excluding/ the
               trailing 0-byte

            */
            FETCH_SIZE;

            format++;
            if (q == NULL && q2 == NULL) {
                Py_DECREF(s);
                return converterr(
                    "(buffer_len is NULL)",
                    arg, msgbuf, bufsize);
            }
            if (*buffer == NULL) {
                *buffer = PyMem_NEW(char, size + 1);
                if (*buffer == NULL) {
                    Py_DECREF(s);
                    PyErr_NoMemory();
                    RETURN_ERR_OCCURRED;
                }
                if (addcleanup(*buffer, freelist, cleanup_ptr)) {
                    Py_DECREF(s);
                    return converterr(
                        "(cleanup problem)",
                        arg, msgbuf, bufsize);
                }
            } else {
                if (size + 1 > BUFFER_LEN) {
                    Py_DECREF(s);
                    PyErr_Format(PyExc_ValueError,
                                 "encoded string too long "
                                 "(%zd, maximum length %zd)",
                                 (Py_ssize_t)size, (Py_ssize_t)(BUFFER_LEN-1));
                    RETURN_ERR_OCCURRED;
                }
            }
            memcpy(*buffer, ptr, size+1);
            STORE_SIZE(size);
        } else {
            /* Using a 0-terminated buffer:

               - the encoded string has to be 0-terminated
               for this variant to work; if it is not, an
               error raised

               - a new buffer of the needed size is
               allocated and the data copied into it;
               *buffer is updated to point to the new
               buffer; the caller is responsible for
               PyMem_Free()ing it after usage

            */
            if ((Py_ssize_t)strlen(ptr) != size) {
                Py_DECREF(s);
                return converterr(
                    "encoded string without null bytes",
                    arg, msgbuf, bufsize);
            }
            *buffer = PyMem_NEW(char, size + 1);
            if (*buffer == NULL) {
                Py_DECREF(s);
                PyErr_NoMemory();
                RETURN_ERR_OCCURRED;
            }
            if (addcleanup(*buffer, freelist, cleanup_ptr)) {
                Py_DECREF(s);
                return converterr("(cleanup problem)",
                                arg, msgbuf, bufsize);
            }
            memcpy(*buffer, ptr, size+1);
        }
        Py_DECREF(s);
        break;
    }

    case 'S': { /* PyBytes object */
        PyObject **p = va_arg(*p_va, PyObject **);
        if (PyBytes_Check(arg))
            *p = arg;
        else
            return converterr("bytes", arg, msgbuf, bufsize);
        break;
    }

    case 'Y': { /* PyByteArray object */
        PyObject **p = va_arg(*p_va, PyObject **);
        if (PyByteArray_Check(arg))
            *p = arg;
        else
            return converterr("bytearray", arg, msgbuf, bufsize);
        break;
    }

    case 'U': { /* PyUnicode object */
        PyObject **p = va_arg(*p_va, PyObject **);
        if (PyUnicode_Check(arg)) {
            if (PyUnicode_READY(arg) == -1)
                RETURN_ERR_OCCURRED;
            *p = arg;
        }
        else
            return converterr("str", arg, msgbuf, bufsize);
        break;
    }

    case 'O': { /* object */
        PyTypeObject *type;
        PyObject **p;
        if (*format == '!') {
            type = va_arg(*p_va, PyTypeObject*);
            p = va_arg(*p_va, PyObject **);
            format++;
            if (PyType_IsSubtype(arg->ob_type, type))
                *p = arg;
            else
                return converterr(type->tp_name, arg, msgbuf, bufsize);

        }
        else if (*format == '&') {
            typedef int (*converter)(PyObject *, void *);
            converter convert = va_arg(*p_va, converter);
            void *addr = va_arg(*p_va, void *);
            int res;
            format++;
            if (! (res = (*convert)(arg, addr)))
                return converterr("(unspecified)",
                                  arg, msgbuf, bufsize);
            if (res == Py_CLEANUP_SUPPORTED &&
                addcleanup(addr, freelist, convert) == -1)
                return converterr("(cleanup problem)",
                                arg, msgbuf, bufsize);
        }
        else {
            p = va_arg(*p_va, PyObject **);
            *p = arg;
        }
        break;
    }


    case 'w': { /* "w*": memory buffer, read-write access */
        void **p = va_arg(*p_va, void **);

        if (*format != '*')
            return converterr(
                "(invalid use of 'w' format character)",
                arg, msgbuf, bufsize);
        format++;

        /* Caller is interested in Py_buffer, and the object
           supports it directly. */
        if (PyObject_GetBuffer(arg, (Py_buffer*)p, PyBUF_WRITABLE) < 0) {
            PyErr_Clear();
            return converterr("read-write bytes-like object",
                              arg, msgbuf, bufsize);
        }
        if (!PyBuffer_IsContiguous((Py_buffer*)p, 'C')) {
            PyBuffer_Release((Py_buffer*)p);
            return converterr("contiguous buffer", arg, msgbuf, bufsize);
        }
        if (addcleanup(p, freelist, cleanup_buffer)) {
            return converterr(
                "(cleanup problem)",
                arg, msgbuf, bufsize);
        }
        break;
    }

    default:
        return converterr("(impossible<bad format char>)", arg, msgbuf, bufsize);

    }

    *p_format = format;
    return NULL;

#undef FETCH_SIZE
#undef STORE_SIZE
#undef BUFFER_LEN
#undef RETURN_ERR_OCCURRED
}

static Py_ssize_t
convertbuffer(PyObject *arg, const void **p, const char **errmsg)
{
    PyBufferProcs *pb = Py_TYPE(arg)->tp_as_buffer;
    Py_ssize_t count;
    Py_buffer view;

    *errmsg = NULL;
    *p = NULL;
    if (pb != NULL && pb->bf_releasebuffer != NULL) {
        *errmsg = "read-only bytes-like object";
        return -1;
    }

    if (getbuffer(arg, &view, errmsg) < 0)
        return -1;
    count = view.len;
    *p = view.buf;
    PyBuffer_Release(&view);
    return count;
}

static int
getbuffer(PyObject *arg, Py_buffer *view, const char **errmsg)
{
    if (PyObject_GetBuffer(arg, view, PyBUF_SIMPLE) != 0) {
        *errmsg = "bytes-like object";
        return -1;
    }
    if (!PyBuffer_IsContiguous(view, 'C')) {
        PyBuffer_Release(view);
        *errmsg = "contiguous buffer";
        return -1;
    }
    return 0;
}

/* Support for keyword arguments donated by
   Geoff Philbrick <philbric@delphi.hks.com> */

/* Return false (0) for error, else true. */
int
PyArg_ParseTupleAndKeywords(PyObject *args,
                            PyObject *keywords,
                            const char *format,
                            char **kwlist, ...)
{
    int retval;
    va_list va;

    if ((args == NULL || !PyTuple_Check(args)) ||
        (keywords != NULL && !PyDict_Check(keywords)) ||
        format == NULL ||
        kwlist == NULL)
    {
        PyErr_BadInternalCall();
        return 0;
    }

    va_start(va, kwlist);
    retval = vgetargskeywords(args, keywords, format, kwlist, &va, 0);
    va_end(va);
    return retval;
}

int
_PyArg_ParseTupleAndKeywords_SizeT(PyObject *args,
                                  PyObject *keywords,
                                  const char *format,
                                  char **kwlist, ...)
{
    int retval;
    va_list va;

    if ((args == NULL || !PyTuple_Check(args)) ||
        (keywords != NULL && !PyDict_Check(keywords)) ||
        format == NULL ||
        kwlist == NULL)
    {
        PyErr_BadInternalCall();
        return 0;
    }

    va_start(va, kwlist);
    retval = vgetargskeywords(args, keywords, format,
                              kwlist, &va, FLAG_SIZE_T);
    va_end(va);
    return retval;
}


int
PyArg_VaParseTupleAndKeywords(PyObject *args,
                              PyObject *keywords,
                              const char *format,
                              char **kwlist, va_list va)
{
    int retval;
    va_list lva;

    if ((args == NULL || !PyTuple_Check(args)) ||
        (keywords != NULL && !PyDict_Check(keywords)) ||
        format == NULL ||
        kwlist == NULL)
    {
        PyErr_BadInternalCall();
        return 0;
    }

    va_copy(lva, va);

    retval = vgetargskeywords(args, keywords, format, kwlist, &lva, 0);
    va_end(lva);
    return retval;
}

int
_PyArg_VaParseTupleAndKeywords_SizeT(PyObject *args,
                                    PyObject *keywords,
                                    const char *format,
                                    char **kwlist, va_list va)
{
    int retval;
    va_list lva;

    if ((args == NULL || !PyTuple_Check(args)) ||
        (keywords != NULL && !PyDict_Check(keywords)) ||
        format == NULL ||
        kwlist == NULL)
    {
        PyErr_BadInternalCall();
        return 0;
    }

    va_copy(lva, va);

    retval = vgetargskeywords(args, keywords, format,
                              kwlist, &lva, FLAG_SIZE_T);
    va_end(lva);
    return retval;
}

int
_PyArg_ParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
                            struct _PyArg_Parser *parser, ...)
{
    int retval;
    va_list va;

    va_start(va, parser);
    retval = vgetargskeywordsfast(args, keywords, parser, &va, 0);
    va_end(va);
    return retval;
}

int
_PyArg_ParseTupleAndKeywordsFast_SizeT(PyObject *args, PyObject *keywords,
                            struct _PyArg_Parser *parser, ...)
{
    int retval;
    va_list va;

    va_start(va, parser);
    retval = vgetargskeywordsfast(args, keywords, parser, &va, FLAG_SIZE_T);
    va_end(va);
    return retval;
}

int
_PyArg_ParseStackAndKeywords(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames,
                  struct _PyArg_Parser *parser, ...)
{
    int retval;
    va_list va;

    va_start(va, parser);
    retval = vgetargskeywordsfast_impl(args, nargs, NULL, kwnames, parser, &va, 0);
    va_end(va);
    return retval;
}

int
_PyArg_ParseStackAndKeywords_SizeT(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames,
                        struct _PyArg_Parser *parser, ...)
{
    int retval;
    va_list va;

    va_start(va, parser);
    retval = vgetargskeywordsfast_impl(args, nargs, NULL, kwnames, parser, &va, FLAG_SIZE_T);
    va_end(va);
    return retval;
}


int
_PyArg_VaParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
                            struct _PyArg_Parser *parser, va_list va)
{
    int retval;
    va_list lva;

    va_copy(lva, va);

    retval = vgetargskeywordsfast(args, keywords, parser, &lva, 0);
    va_end(lva);
    return retval;
}

int
_PyArg_VaParseTupleAndKeywordsFast_SizeT(PyObject *args, PyObject *keywords,
                            struct _PyArg_Parser *parser, va_list va)
{
    int retval;
    va_list lva;

    va_copy(lva, va);

    retval = vgetargskeywordsfast(args, keywords, parser, &lva, FLAG_SIZE_T);
    va_end(lva);
    return retval;
}

int
PyArg_ValidateKeywordArguments(PyObject *kwargs)
{
    if (!PyDict_Check(kwargs)) {
        PyErr_BadInternalCall();
        return 0;
    }
    if (!_PyDict_HasOnlyStringKeys(kwargs)) {
        PyErr_SetString(PyExc_TypeError,
                        "keywords must be strings");
        return 0;
    }
    return 1;
}

#define IS_END_OF_FORMAT(c) (c == '\0' || c == ';' || c == ':')

static int
vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
                 char **kwlist, va_list *p_va, int flags)
{
    char msgbuf[512];
    int levels[32];
    const char *fname, *msg, *custom_msg;
    int min = INT_MAX;
    int max = INT_MAX;
    int i, pos, len;
    int skip = 0;
    Py_ssize_t nargs, nkwargs;
    PyObject *current_arg;
    freelistentry_t static_entries[STATIC_FREELIST_ENTRIES];
    freelist_t freelist;

    freelist.entries = static_entries;
    freelist.first_available = 0;
    freelist.entries_malloced = 0;

    assert(args != NULL && PyTuple_Check(args));
    assert(kwargs == NULL || PyDict_Check(kwargs));
    assert(format != NULL);
    assert(kwlist != NULL);
    assert(p_va != NULL);

    /* grab the function name or custom error msg first (mutually exclusive) */
    fname = strchr(format, ':');
    if (fname) {
        fname++;
        custom_msg = NULL;
    }
    else {
        custom_msg = strchr(format,';');
        if (custom_msg)
            custom_msg++;
    }

    /* scan kwlist and count the number of positional-only parameters */
    for (pos = 0; kwlist[pos] && !*kwlist[pos]; pos++) {
    }
    /* scan kwlist and get greatest possible nbr of args */
    for (len = pos; kwlist[len]; len++) {
        if (!*kwlist[len]) {
            PyErr_SetString(PyExc_SystemError,
                            "Empty keyword parameter name");
            return cleanreturn(0, &freelist);
        }
    }

    if (len > STATIC_FREELIST_ENTRIES) {
        freelist.entries = PyMem_NEW(freelistentry_t, len);
        if (freelist.entries == NULL) {
            PyErr_NoMemory();
            return 0;
        }
        freelist.entries_malloced = 1;
    }

    nargs = PyTuple_GET_SIZE(args);
    nkwargs = (kwargs == NULL) ? 0 : PyDict_GET_SIZE(kwargs);
    if (nargs + nkwargs > len) {
        /* Adding "keyword" (when nargs == 0) prevents producing wrong error
           messages in some special cases (see bpo-31229). */
        PyErr_Format(PyExc_TypeError,
                     "%.200s%s takes at most %d %sargument%s (%zd given)",
                     (fname == NULL) ? "function" : fname,
                     (fname == NULL) ? "" : "()",
                     len,
                     (nargs == 0) ? "keyword " : "",
                     (len == 1) ? "" : "s",
                     nargs + nkwargs);
        return cleanreturn(0, &freelist);
    }

    /* convert tuple args and keyword args in same loop, using kwlist to drive process */
    for (i = 0; i < len; i++) {
        if (*format == '|') {
            if (min != INT_MAX) {
                PyErr_SetString(PyExc_SystemError,
                                "Invalid format string (| specified twice)");
                return cleanreturn(0, &freelist);
            }

            min = i;
            format++;

            if (max != INT_MAX) {
                PyErr_SetString(PyExc_SystemError,
                                "Invalid format string ($ before |)");
                return cleanreturn(0, &freelist);
            }
        }
        if (*format == '$') {
            if (max != INT_MAX) {
                PyErr_SetString(PyExc_SystemError,
                                "Invalid format string ($ specified twice)");
                return cleanreturn(0, &freelist);
            }

            max = i;
            format++;

            if (max < pos) {
                PyErr_SetString(PyExc_SystemError,
                                "Empty parameter name after $");
                return cleanreturn(0, &freelist);
            }
            if (skip) {
                /* Now we know the minimal and the maximal numbers of
                 * positional arguments and can raise an exception with
                 * informative message (see below). */
                break;
            }
            if (max < nargs) {
                if (max == 0) {
                    PyErr_Format(PyExc_TypeError,
                                 "%.200s%s takes no positional arguments",
                                 (fname == NULL) ? "function" : fname,
                                 (fname == NULL) ? "" : "()");
                }
                else {
                    PyErr_Format(PyExc_TypeError,
                                 "%.200s%s takes %s %d positional argument%s"
                                 " (%zd given)",
                                 (fname == NULL) ? "function" : fname,
                                 (fname == NULL) ? "" : "()",
                                 (min != INT_MAX) ? "at most" : "exactly",
                                 max,
                                 max == 1 ? "" : "s",
                                 nargs);
                }
                return cleanreturn(0, &freelist);
            }
        }
        if (IS_END_OF_FORMAT(*format)) {
            PyErr_Format(PyExc_SystemError,
                         "More keyword list entries (%d) than "
                         "format specifiers (%d)", len, i);
            return cleanreturn(0, &freelist);
        }
        if (!skip) {
            if (i < nargs) {
                current_arg = PyTuple_GET_ITEM(args, i);
            }
            else if (nkwargs && i >= pos) {
                current_arg = _PyDict_GetItemStringWithError(kwargs, kwlist[i]);
                if (current_arg) {
                    --nkwargs;
                }
                else if (PyErr_Occurred()) {
                    return cleanreturn(0, &freelist);
                }
            }
            else {
                current_arg = NULL;
            }

            if (current_arg) {
                msg = convertitem(current_arg, &format, p_va, flags,
                    levels, msgbuf, sizeof(msgbuf), &freelist);
                if (msg) {
                    seterror(i+1, msg, levels, fname, custom_msg);
                    return cleanreturn(0, &freelist);
                }
                continue;
            }

            if (i < min) {
                if (i < pos) {
                    assert (min == INT_MAX);
                    assert (max == INT_MAX);
                    skip = 1;
                    /* At that moment we still don't know the minimal and
                     * the maximal numbers of positional arguments.  Raising
                     * an exception is deferred until we encounter | and $
                     * or the end of the format. */
                }
                else {
                    PyErr_Format(PyExc_TypeError,  "%.200s%s missing required "
                                 "argument '%s' (pos %d)",
                                 (fname == NULL) ? "function" : fname,
                                 (fname == NULL) ? "" : "()",
                                 kwlist[i], i+1);
                    return cleanreturn(0, &freelist);
                }
            }
            /* current code reports success when all required args
             * fulfilled and no keyword args left, with no further
             * validation. XXX Maybe skip this in debug build ?
             */
            if (!nkwargs && !skip) {
                return cleanreturn(1, &freelist);
            }
        }

        /* We are into optional args, skip through to any remaining
         * keyword args */
        msg = skipitem(&format, p_va, flags);
        if (msg) {
            PyErr_Format(PyExc_SystemError, "%s: '%s'", msg,
                         format);
            return cleanreturn(0, &freelist);
        }
    }

    if (skip) {
        PyErr_Format(PyExc_TypeError,
                     "%.200s%s takes %s %d positional argument%s"
                     " (%zd given)",
                     (fname == NULL) ? "function" : fname,
                     (fname == NULL) ? "" : "()",
                     (Py_MIN(pos, min) < i) ? "at least" : "exactly",
                     Py_MIN(pos, min),
                     Py_MIN(pos, min) == 1 ? "" : "s",
                     nargs);
        return cleanreturn(0, &freelist);
    }

    if (!IS_END_OF_FORMAT(*format) && (*format != '|') && (*format != '$')) {
        PyErr_Format(PyExc_SystemError,
            "more argument specifiers than keyword list entries "
            "(remaining format:'%s')", format);
        return cleanreturn(0, &freelist);
    }

    if (nkwargs > 0) {
        PyObject *key;
        Py_ssize_t j;
        /* make sure there are no arguments given by name and position */
        for (i = pos; i < nargs; i++) {
            current_arg = _PyDict_GetItemStringWithError(kwargs, kwlist[i]);
            if (current_arg) {
                /* arg present in tuple and in dict */
                PyErr_Format(PyExc_TypeError,
                             "argument for %.200s%s given by name ('%s') "
                             "and position (%d)",
                             (fname == NULL) ? "function" : fname,
                             (fname == NULL) ? "" : "()",
                             kwlist[i], i+1);
                return cleanreturn(0, &freelist);
            }
            else if (PyErr_Occurred()) {
                return cleanreturn(0, &freelist);
            }
        }
        /* make sure there are no extraneous keyword arguments */
        j = 0;
        while (PyDict_Next(kwargs, &j, &key, NULL)) {
            int match = 0;
            if (!PyUnicode_Check(key)) {
                PyErr_SetString(PyExc_TypeError,
                                "keywords must be strings");
                return cleanreturn(0, &freelist);
            }
            for (i = pos; i < len; i++) {
                if (_PyUnicode_EqualToASCIIString(key, kwlist[i])) {
                    match = 1;
                    break;
                }
            }
            if (!match) {
                PyErr_Format(PyExc_TypeError,
                             "'%U' is an invalid keyword "
                             "argument for %.200s%s",
                             key,
                             (fname == NULL) ? "this function" : fname,
                             (fname == NULL) ? "" : "()");
                return cleanreturn(0, &freelist);
            }
        }
    }

    return cleanreturn(1, &freelist);
}


/* List of static parsers. */
static struct _PyArg_Parser *static_arg_parsers = NULL;

static int
parser_init(struct _PyArg_Parser *parser)
{
    const char * const *keywords;
    const char *format, *msg;
    int i, len, min, max, nkw;
    PyObject *kwtuple;

    assert(parser->keywords != NULL);
    if (parser->kwtuple != NULL) {
        return 1;
    }

    keywords = parser->keywords;
    /* scan keywords and count the number of positional-only parameters */
    for (i = 0; keywords[i] && !*keywords[i]; i++) {
    }
    parser->pos = i;
    /* scan keywords and get greatest possible nbr of args */
    for (; keywords[i]; i++) {
        if (!*keywords[i]) {
            PyErr_SetString(PyExc_SystemError,
                            "Empty keyword parameter name");
            return 0;
        }
    }
    len = i;

    format = parser->format;
    if (format) {
        /* grab the function name or custom error msg first (mutually exclusive) */
        parser->fname = strchr(parser->format, ':');
        if (parser->fname) {
            parser->fname++;
            parser->custom_msg = NULL;
        }
        else {
            parser->custom_msg = strchr(parser->format,';');
            if (parser->custom_msg)
                parser->custom_msg++;
        }

        min = max = INT_MAX;
        for (i = 0; i < len; i++) {
            if (*format == '|') {
                if (min != INT_MAX) {
                    PyErr_SetString(PyExc_SystemError,
                                    "Invalid format string (| specified twice)");
                    return 0;
                }
                if (max != INT_MAX) {
                    PyErr_SetString(PyExc_SystemError,
                                    "Invalid format string ($ before |)");
                    return 0;
                }
                min = i;
                format++;
            }
            if (*format == '$') {
                if (max != INT_MAX) {
                    PyErr_SetString(PyExc_SystemError,
                                    "Invalid format string ($ specified twice)");
                    return 0;
                }
                if (i < parser->pos) {
                    PyErr_SetString(PyExc_SystemError,
                                    "Empty parameter name after $");
                    return 0;
                }
                max = i;
                format++;
            }
            if (IS_END_OF_FORMAT(*format)) {
                PyErr_Format(PyExc_SystemError,
                            "More keyword list entries (%d) than "
                            "format specifiers (%d)", len, i);
                return 0;
            }

            msg = skipitem(&format, NULL, 0);
            if (msg) {
                PyErr_Format(PyExc_SystemError, "%s: '%s'", msg,
                            format);
                return 0;
            }
        }
        parser->min = Py_MIN(min, len);
        parser->max = Py_MIN(max, len);

        if (!IS_END_OF_FORMAT(*format) && (*format != '|') && (*format != '$')) {
            PyErr_Format(PyExc_SystemError,
                "more argument specifiers than keyword list entries "
                "(remaining format:'%s')", format);
            return 0;
        }
    }

    nkw = len - parser->pos;
    kwtuple = PyTuple_New(nkw);
    if (kwtuple == NULL) {
        return 0;
    }
    keywords = parser->keywords + parser->pos;
    for (i = 0; i < nkw; i++) {
        PyObject *str = PyUnicode_FromString(keywords[i]);
        if (str == NULL) {
            Py_DECREF(kwtuple);
            return 0;
        }
        PyUnicode_InternInPlace(&str);
        PyTuple_SET_ITEM(kwtuple, i, str);
    }
    parser->kwtuple = kwtuple;

    assert(parser->next == NULL);
    parser->next = static_arg_parsers;
    static_arg_parsers = parser;
    return 1;
}

static void
parser_clear(struct _PyArg_Parser *parser)
{
    Py_CLEAR(parser->kwtuple);
}

static PyObject*
find_keyword(PyObject *kwnames, PyObject *const *kwstack, PyObject *key)
{
    Py_ssize_t i, nkwargs;

    nkwargs = PyTuple_GET_SIZE(kwnames);
    for (i=0; i < nkwargs; i++) {
        PyObject *kwname = PyTuple_GET_ITEM(kwnames, i);

        /* ptr==ptr should match in most cases since keyword keys
           should be interned strings */
        if (kwname == key) {
            return kwstack[i];
        }
        if (!PyUnicode_Check(kwname)) {
            /* ignore non-string keyword keys:
               an error will be raised below */
            continue;
        }
        if (_PyUnicode_EQ(kwname, key)) {
            return kwstack[i];
        }
    }
    return NULL;
}

static int
vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
                          PyObject *kwargs, PyObject *kwnames,
                          struct _PyArg_Parser *parser,
                          va_list *p_va, int flags)
{
    PyObject *kwtuple;
    char msgbuf[512];
    int levels[32];
    const char *format;
    const char *msg;
    PyObject *keyword;
    int i, pos, len;
    Py_ssize_t nkwargs;
    PyObject *current_arg;
    freelistentry_t static_entries[STATIC_FREELIST_ENTRIES];
    freelist_t freelist;
    PyObject *const *kwstack = NULL;

    freelist.entries = static_entries;
    freelist.first_available = 0;
    freelist.entries_malloced = 0;

    assert(kwargs == NULL || PyDict_Check(kwargs));
    assert(kwargs == NULL || kwnames == NULL);
    assert(p_va != NULL);

    if (parser == NULL) {
        PyErr_BadInternalCall();
        return 0;
    }

    if (kwnames != NULL && !PyTuple_Check(kwnames)) {
        PyErr_BadInternalCall();
        return 0;
    }

    if (!parser_init(parser)) {
        return 0;
    }

    kwtuple = parser->kwtuple;
    pos = parser->pos;
    len = pos + (int)PyTuple_GET_SIZE(kwtuple);

    if (len > STATIC_FREELIST_ENTRIES) {
        freelist.entries = PyMem_NEW(freelistentry_t, len);
        if (freelist.entries == NULL) {
            PyErr_NoMemory();
            return 0;
        }
        freelist.entries_malloced = 1;
    }

    if (kwargs != NULL) {
        nkwargs = PyDict_GET_SIZE(kwargs);
    }
    else if (kwnames != NULL) {
        nkwargs = PyTuple_GET_SIZE(kwnames);
        kwstack = args + nargs;
    }
    else {
        nkwargs = 0;
    }
    if (nargs + nkwargs > len) {
        /* Adding "keyword" (when nargs == 0) prevents producing wrong error
           messages in some special cases (see bpo-31229). */
        PyErr_Format(PyExc_TypeError,
                     "%.200s%s takes at most %d %sargument%s (%zd given)",
                     (parser->fname == NULL) ? "function" : parser->fname,
                     (parser->fname == NULL) ? "" : "()",
                     len,
                     (nargs == 0) ? "keyword " : "",
                     (len == 1) ? "" : "s",
                     nargs + nkwargs);
        return cleanreturn(0, &freelist);
    }
    if (parser->max < nargs) {
        if (parser->max == 0) {
            PyErr_Format(PyExc_TypeError,
                         "%.200s%s takes no positional arguments",
                         (parser->fname == NULL) ? "function" : parser->fname,
                         (parser->fname == NULL) ? "" : "()");
        }
        else {
            PyErr_Format(PyExc_TypeError,
                         "%.200s%s takes %s %d positional argument%s (%zd given)",
                         (parser->fname == NULL) ? "function" : parser->fname,
                         (parser->fname == NULL) ? "" : "()",
                         (parser->min < parser->max) ? "at most" : "exactly",
                         parser->max,
                         parser->max == 1 ? "" : "s",
                         nargs);
        }
        return cleanreturn(0, &freelist);
    }

    format = parser->format;
    /* convert tuple args and keyword args in same loop, using kwtuple to drive process */
    for (i = 0; i < len; i++) {
        if (*format == '|') {
            format++;
        }
        if (*format == '$') {
            format++;
        }
        assert(!IS_END_OF_FORMAT(*format));

        if (i < nargs) {
            current_arg = args[i];
        }
        else if (nkwargs && i >= pos) {
            keyword = PyTuple_GET_ITEM(kwtuple, i - pos);
            if (kwargs != NULL) {
                current_arg = PyDict_GetItemWithError(kwargs, keyword);
                if (!current_arg && PyErr_Occurred()) {
                    return cleanreturn(0, &freelist);
                }
            }
            else {
                current_arg = find_keyword(kwnames, kwstack, keyword);
            }
            if (current_arg) {
                --nkwargs;
            }
        }
        else {
            current_arg = NULL;
        }

        if (current_arg) {
            msg = convertitem(current_arg, &format, p_va, flags,
                levels, msgbuf, sizeof(msgbuf), &freelist);
            if (msg) {
                seterror(i+1, msg, levels, parser->fname, parser->custom_msg);
                return cleanreturn(0, &freelist);
            }
            continue;
        }

        if (i < parser->min) {
            /* Less arguments than required */
            if (i < pos) {
                Py_ssize_t min = Py_MIN(pos, parser->min);
                PyErr_Format(PyExc_TypeError,
                             "%.200s%s takes %s %d positional argument%s"
                             " (%zd given)",
                             (parser->fname == NULL) ? "function" : parser->fname,
                             (parser->fname == NULL) ? "" : "()",
                             min < parser->max ? "at least" : "exactly",
                             min,
                             min == 1 ? "" : "s",
                             nargs);
            }
            else {
                keyword = PyTuple_GET_ITEM(kwtuple, i - pos);
                PyErr_Format(PyExc_TypeError,  "%.200s%s missing required "
                             "argument '%U' (pos %d)",
                             (parser->fname == NULL) ? "function" : parser->fname,
                             (parser->fname == NULL) ? "" : "()",
                             keyword, i+1);
            }
            return cleanreturn(0, &freelist);
        }
        /* current code reports success when all required args
         * fulfilled and no keyword args left, with no further
         * validation. XXX Maybe skip this in debug build ?
         */
        if (!nkwargs) {
            return cleanreturn(1, &freelist);
        }

        /* We are into optional args, skip through to any remaining
         * keyword args */
        msg = skipitem(&format, p_va, flags);
        assert(msg == NULL);
    }

    assert(IS_END_OF_FORMAT(*format) || (*format == '|') || (*format == '$'));

    if (nkwargs > 0) {
        Py_ssize_t j;
        /* make sure there are no arguments given by name and position */
        for (i = pos; i < nargs; i++) {
            keyword = PyTuple_GET_ITEM(kwtuple, i - pos);
            if (kwargs != NULL) {
                current_arg = PyDict_GetItemWithError(kwargs, keyword);
                if (!current_arg && PyErr_Occurred()) {
                    return cleanreturn(0, &freelist);
                }
            }
            else {
                current_arg = find_keyword(kwnames, kwstack, keyword);
            }
            if (current_arg) {
                /* arg present in tuple and in dict */
                PyErr_Format(PyExc_TypeError,
                             "argument for %.200s%s given by name ('%U') "
                             "and position (%d)",
                             (parser->fname == NULL) ? "function" : parser->fname,
                             (parser->fname == NULL) ? "" : "()",
                             keyword, i+1);
                return cleanreturn(0, &freelist);
            }
        }
        /* make sure there are no extraneous keyword arguments */
        j = 0;
        while (1) {
            int match;
            if (kwargs != NULL) {
                if (!PyDict_Next(kwargs, &j, &keyword, NULL))
                    break;
            }
            else {
                if (j >= PyTuple_GET_SIZE(kwnames))
                    break;
                keyword = PyTuple_GET_ITEM(kwnames, j);
                j++;
            }

            if (!PyUnicode_Check(keyword)) {
                PyErr_SetString(PyExc_TypeError,
                                "keywords must be strings");
                return cleanreturn(0, &freelist);
            }
            match = PySequence_Contains(kwtuple, keyword);
            if (match <= 0) {
                if (!match) {
                    PyErr_Format(PyExc_TypeError,
                                 "'%U' is an invalid keyword "
                                 "argument for %.200s%s",
                                 keyword,
                                 (parser->fname == NULL) ? "this function" : parser->fname,
                                 (parser->fname == NULL) ? "" : "()");
                }
                return cleanreturn(0, &freelist);
            }
        }
    }

    return cleanreturn(1, &freelist);
}

static int
vgetargskeywordsfast(PyObject *args, PyObject *keywords,
                     struct _PyArg_Parser *parser, va_list *p_va, int flags)
{
    PyObject **stack;
    Py_ssize_t nargs;

    if (args == NULL
        || !PyTuple_Check(args)
        || (keywords != NULL && !PyDict_Check(keywords)))
    {
        PyErr_BadInternalCall();
        return 0;
    }

    stack = _PyTuple_ITEMS(args);
    nargs = PyTuple_GET_SIZE(args);
    return vgetargskeywordsfast_impl(stack, nargs, keywords, NULL,
                                     parser, p_va, flags);
}


#undef _PyArg_UnpackKeywords

PyObject * const *
_PyArg_UnpackKeywords(PyObject *const *args, Py_ssize_t nargs,
                      PyObject *kwargs, PyObject *kwnames,
                      struct _PyArg_Parser *parser,
                      int minpos, int maxpos, int minkw,
                      PyObject **buf)
{
    PyObject *kwtuple;
    PyObject *keyword;
    int i, posonly, minposonly, maxargs;
    int reqlimit = minkw ? maxpos + minkw : minpos;
    Py_ssize_t nkwargs;
    PyObject *current_arg;
    PyObject * const *kwstack = NULL;

    assert(kwargs == NULL || PyDict_Check(kwargs));
    assert(kwargs == NULL || kwnames == NULL);

    if (parser == NULL) {
        PyErr_BadInternalCall();
        return NULL;
    }

    if (kwnames != NULL && !PyTuple_Check(kwnames)) {
        PyErr_BadInternalCall();
        return NULL;
    }

    if (args == NULL && nargs == 0) {
        args = buf;
    }

    if (!parser_init(parser)) {
        return NULL;
    }

    kwtuple = parser->kwtuple;
    posonly = parser->pos;
    minposonly = Py_MIN(posonly, minpos);
    maxargs = posonly + (int)PyTuple_GET_SIZE(kwtuple);

    if (kwargs != NULL) {
        nkwargs = PyDict_GET_SIZE(kwargs);
    }
    else if (kwnames != NULL) {
        nkwargs = PyTuple_GET_SIZE(kwnames);
        kwstack = args + nargs;
    }
    else {
        nkwargs = 0;
    }
    if (nkwargs == 0 && minkw == 0 && minpos <= nargs && nargs <= maxpos) {
        /* Fast path. */
        return args;
    }
    if (nargs + nkwargs > maxargs) {
        /* Adding "keyword" (when nargs == 0) prevents producing wrong error
           messages in some special cases (see bpo-31229). */
        PyErr_Format(PyExc_TypeError,
                     "%.200s%s takes at most %d %sargument%s (%zd given)",
                     (parser->fname == NULL) ? "function" : parser->fname,
                     (parser->fname == NULL) ? "" : "()",
                     maxargs,
                     (nargs == 0) ? "keyword " : "",
                     (maxargs == 1) ? "" : "s",
                     nargs + nkwargs);
        return NULL;
    }
    if (nargs > maxpos) {
        if (maxpos == 0) {
            PyErr_Format(PyExc_TypeError,
                         "%.200s%s takes no positional arguments",
                         (parser->fname == NULL) ? "function" : parser->fname,
                         (parser->fname == NULL) ? "" : "()");
        }
        else {
            PyErr_Format(PyExc_TypeError,
                         "%.200s%s takes %s %d positional argument%s (%zd given)",
                         (parser->fname == NULL) ? "function" : parser->fname,
                         (parser->fname == NULL) ? "" : "()",
                         (minpos < maxpos) ? "at most" : "exactly",
                         maxpos,
                         (maxpos == 1) ? "" : "s",
                         nargs);
        }
        return NULL;
    }
    if (nargs < minposonly) {
        PyErr_Format(PyExc_TypeError,
                     "%.200s%s takes %s %d positional argument%s"
                     " (%zd given)",
                     (parser->fname == NULL) ? "function" : parser->fname,
                     (parser->fname == NULL) ? "" : "()",
                     minposonly < maxpos ? "at least" : "exactly",
                     minposonly,
                     minposonly == 1 ? "" : "s",
                     nargs);
        return NULL;
    }

    /* copy tuple args */
    for (i = 0; i < nargs; i++) {
        buf[i] = args[i];
    }

    /* copy keyword args using kwtuple to drive process */
    for (i = Py_MAX((int)nargs, posonly); i < maxargs; i++) {
        if (nkwargs) {
            keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
            if (kwargs != NULL) {
                current_arg = PyDict_GetItemWithError(kwargs, keyword);
                if (!current_arg && PyErr_Occurred()) {
                    return NULL;
                }
            }
            else {
                current_arg = find_keyword(kwnames, kwstack, keyword);
            }
        }
        else if (i >= reqlimit) {
            break;
        }
        else {
            current_arg = NULL;
        }

        buf[i] = current_arg;

        if (current_arg) {
            --nkwargs;
        }
        else if (i < minpos || (maxpos <= i && i < reqlimit)) {
            /* Less arguments than required */
            keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
            PyErr_Format(PyExc_TypeError,  "%.200s%s missing required "
                         "argument '%U' (pos %d)",
                         (parser->fname == NULL) ? "function" : parser->fname,
                         (parser->fname == NULL) ? "" : "()",
                         keyword, i+1);
            return NULL;
        }
    }

    if (nkwargs > 0) {
        Py_ssize_t j;
        /* make sure there are no arguments given by name and position */
        for (i = posonly; i < nargs; i++) {
            keyword = PyTuple_GET_ITEM(kwtuple, i - posonly);
            if (kwargs != NULL) {
                current_arg = PyDict_GetItemWithError(kwargs, keyword);
                if (!current_arg && PyErr_Occurred()) {
                    return NULL;
                }
            }
            else {
                current_arg = find_keyword(kwnames, kwstack, keyword);
            }
            if (current_arg) {
                /* arg present in tuple and in dict */
                PyErr_Format(PyExc_TypeError,
                             "argument for %.200s%s given by name ('%U') "
                             "and position (%d)",
                             (parser->fname == NULL) ? "function" : parser->fname,
                             (parser->fname == NULL) ? "" : "()",
                             keyword, i+1);
                return NULL;
            }
        }
        /* make sure there are no extraneous keyword arguments */
        j = 0;
        while (1) {
            int match;
            if (kwargs != NULL) {
                if (!PyDict_Next(kwargs, &j, &keyword, NULL))
                    break;
            }
            else {
                if (j >= PyTuple_GET_SIZE(kwnames))
                    break;
                keyword = PyTuple_GET_ITEM(kwnames, j);
                j++;
            }

            if (!PyUnicode_Check(keyword)) {
                PyErr_SetString(PyExc_TypeError,
                                "keywords must be strings");
                return NULL;
            }
            match = PySequence_Contains(kwtuple, keyword);
            if (match <= 0) {
                if (!match) {
                    PyErr_Format(PyExc_TypeError,
                                 "'%U' is an invalid keyword "
                                 "argument for %.200s%s",
                                 keyword,
                                 (parser->fname == NULL) ? "this function" : parser->fname,
                                 (parser->fname == NULL) ? "" : "()");
                }
                return NULL;
            }
        }
    }

    return buf;
}


static const char *
skipitem(const char **p_format, va_list *p_va, int flags)
{
    const char *format = *p_format;
    char c = *format++;

    switch (c) {

    /*
     * codes that take a single data pointer as an argument
     * (the type of the pointer is irrelevant)
     */

    case 'b': /* byte -- very short int */
    case 'B': /* byte as bitfield */
    case 'h': /* short int */
    case 'H': /* short int as bitfield */
    case 'i': /* int */
    case 'I': /* int sized bitfield */
    case 'l': /* long int */
    case 'k': /* long int sized bitfield */
    case 'L': /* long long */
    case 'K': /* long long sized bitfield */
    case 'n': /* Py_ssize_t */
    case 'f': /* float */
    case 'd': /* double */
    case 'D': /* complex double */
    case 'c': /* char */
    case 'C': /* unicode char */
    case 'p': /* boolean predicate */
    case 'S': /* string object */
    case 'Y': /* string object */
    case 'U': /* unicode string object */
        {
            if (p_va != NULL) {
                (void) va_arg(*p_va, void *);
            }
            break;
        }

    /* string codes */

    case 'e': /* string with encoding */
        {
            if (p_va != NULL) {
                (void) va_arg(*p_va, const char *);
            }
            if (!(*format == 's' || *format == 't'))
                /* after 'e', only 's' and 't' is allowed */
                goto err;
            format++;
        }
        /* fall through */

    case 's': /* string */
    case 'z': /* string or None */
    case 'y': /* bytes */
    case 'u': /* unicode string */
    case 'Z': /* unicode string or None */
    case 'w': /* buffer, read-write */
        {
            if (p_va != NULL) {
                (void) va_arg(*p_va, char **);
            }
            if (*format == '#') {
                if (p_va != NULL) {
                    if (flags & FLAG_SIZE_T)
                        (void) va_arg(*p_va, Py_ssize_t *);
                    else {
                        if (PyErr_WarnEx(PyExc_DeprecationWarning,
                                    "PY_SSIZE_T_CLEAN will be required for '#' formats", 1)) {
                            return NULL;
                        }
                        (void) va_arg(*p_va, int *);
                    }
                }
                format++;
            } else if ((c == 's' || c == 'z' || c == 'y' || c == 'w')
                       && *format == '*')
            {
                format++;
            }
            break;
        }

    case 'O': /* object */
        {
            if (*format == '!') {
                format++;
                if (p_va != NULL) {
                    (void) va_arg(*p_va, PyTypeObject*);
                    (void) va_arg(*p_va, PyObject **);
                }
            }
            else if (*format == '&') {
                typedef int (*converter)(PyObject *, void *);
                if (p_va != NULL) {
                    (void) va_arg(*p_va, converter);
                    (void) va_arg(*p_va, void *);
                }
                format++;
            }
            else {
                if (p_va != NULL) {
                    (void) va_arg(*p_va, PyObject **);
                }
            }
            break;
        }

    case '(':           /* bypass tuple, not handled at all previously */
        {
            const char *msg;
            for (;;) {
                if (*format==')')
                    break;
                if (IS_END_OF_FORMAT(*format))
                    return "Unmatched left paren in format "
                           "string";
                msg = skipitem(&format, p_va, flags);
                if (msg)
                    return msg;
            }
            format++;
            break;
        }

    case ')':
        return "Unmatched right paren in format string";

    default:
err:
        return "impossible<bad format char>";

    }

    *p_format = format;
    return NULL;
}


#undef _PyArg_CheckPositional

int
_PyArg_CheckPositional(const char *name, Py_ssize_t nargs,
                       Py_ssize_t min, Py_ssize_t max)
{
    assert(min >= 0);
    assert(min <= max);

    if (nargs < min) {
        if (name != NULL)
            PyErr_Format(
                PyExc_TypeError,
                "%.200s expected %s%zd argument%s, got %zd",
                name, (min == max ? "" : "at least "), min, min == 1 ? "" : "s", nargs);
        else
            PyErr_Format(
                PyExc_TypeError,
                "unpacked tuple should have %s%zd element%s,"
                " but has %zd",
                (min == max ? "" : "at least "), min, min == 1 ? "" : "s", nargs);
        return 0;
    }

    if (nargs == 0) {
        return 1;
    }

    if (nargs > max) {
        if (name != NULL)
            PyErr_Format(
                PyExc_TypeError,
                "%.200s expected %s%zd argument%s, got %zd",
                name, (min == max ? "" : "at most "), max, max == 1 ? "" : "s", nargs);
        else
            PyErr_Format(
                PyExc_TypeError,
                "unpacked tuple should have %s%zd element%s,"
                " but has %zd",
                (min == max ? "" : "at most "), max, max == 1 ? "" : "s", nargs);
        return 0;
    }

    return 1;
}

static int
unpack_stack(PyObject *const *args, Py_ssize_t nargs, const char *name,
             Py_ssize_t min, Py_ssize_t max, va_list vargs)
{
    Py_ssize_t i;
    PyObject **o;

    if (!_PyArg_CheckPositional(name, nargs, min, max)) {
        return 0;
    }

    for (i = 0; i < nargs; i++) {
        o = va_arg(vargs, PyObject **);
        *o = args[i];
    }
    return 1;
}

int
PyArg_UnpackTuple(PyObject *args, const char *name, Py_ssize_t min, Py_ssize_t max, ...)
{
    PyObject **stack;
    Py_ssize_t nargs;
    int retval;
    va_list vargs;

    if (!PyTuple_Check(args)) {
        PyErr_SetString(PyExc_SystemError,
            "PyArg_UnpackTuple() argument list is not a tuple");
        return 0;
    }
    stack = _PyTuple_ITEMS(args);
    nargs = PyTuple_GET_SIZE(args);

#ifdef HAVE_STDARG_PROTOTYPES
    va_start(vargs, max);
#else
    va_start(vargs);
#endif
    retval = unpack_stack(stack, nargs, name, min, max, vargs);
    va_end(vargs);
    return retval;
}

int
_PyArg_UnpackStack(PyObject *const *args, Py_ssize_t nargs, const char *name,
                   Py_ssize_t min, Py_ssize_t max, ...)
{
    int retval;
    va_list vargs;

#ifdef HAVE_STDARG_PROTOTYPES
    va_start(vargs, max);
#else
    va_start(vargs);
#endif
    retval = unpack_stack(args, nargs, name, min, max, vargs);
    va_end(vargs);
    return retval;
}


#undef _PyArg_NoKeywords
#undef _PyArg_NoPositional

/* For type constructors that don't take keyword args
 *
 * Sets a TypeError and returns 0 if the args/kwargs is
 * not empty, returns 1 otherwise
 */
int
_PyArg_NoKeywords(const char *funcname, PyObject *kwargs)
{
    if (kwargs == NULL) {
        return 1;
    }
    if (!PyDict_CheckExact(kwargs)) {
        PyErr_BadInternalCall();
        return 0;
    }
    if (PyDict_GET_SIZE(kwargs) == 0) {
        return 1;
    }

    PyErr_Format(PyExc_TypeError, "%.200s() takes no keyword arguments",
                    funcname);
    return 0;
}


int
_PyArg_NoPositional(const char *funcname, PyObject *args)
{
    if (args == NULL)
        return 1;
    if (!PyTuple_CheckExact(args)) {
        PyErr_BadInternalCall();
        return 0;
    }
    if (PyTuple_GET_SIZE(args) == 0)
        return 1;

    PyErr_Format(PyExc_TypeError, "%.200s() takes no positional arguments",
                    funcname);
    return 0;
}

void
_PyArg_Fini(void)
{
    struct _PyArg_Parser *tmp, *s = static_arg_parsers;
    while (s) {
        tmp = s->next;
        s->next = NULL;
        parser_clear(s);
        s = tmp;
    }
    static_arg_parsers = NULL;
}

#ifdef __cplusplus
};
#endif
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