[Numpy-svn] r4005 - branches/py3k/Modules

numpy-svn@scip... numpy-svn@scip...
Fri Aug 24 15:04:14 CDT 2007


Author: chris.burns
Date: 2007-08-24 15:04:08 -0500 (Fri, 24 Aug 2007)
New Revision: 4005

Added:
   branches/py3k/Modules/_struct.c
Log:
Add the struct module source.  Mostly consists of edits by Travis.  Travis emailed me this code prior to the Google Sprint.  May have a few of my edits.

Added: branches/py3k/Modules/_struct.c
===================================================================
--- branches/py3k/Modules/_struct.c	2007-08-24 19:54:12 UTC (rev 4004)
+++ branches/py3k/Modules/_struct.c	2007-08-24 20:04:08 UTC (rev 4005)
@@ -0,0 +1,2157 @@
+
+/* struct module -- pack values into and (out of) strings */
+
+/* New version supporting byte order, alignment and size options,
+  character strings, and unsigned numbers */
+
+#define PY_SSIZE_T_CLEAN
+
+#include "Python.h"
+#include "structseq.h"
+#include "structmember.h"
+#include <ctype.h>
+
+static PyTypeObject PyStructType;
+static PyTypeObject PyFieldTupleType;
+
+/* If PY_STRUCT_OVERFLOW_MASKING is defined, the struct module will wrap all input
+  numbers for explicit endians such that they fit in the given type, much
+  like explicit casting in C. A warning will be raised if the number did
+  not originally fit within the range of the requested type. If it is
+  not defined, then all range errors and overflow will be struct.error
+  exceptions. */
+
+#define PY_STRUCT_OVERFLOW_MASKING 1
+
+#ifdef PY_STRUCT_OVERFLOW_MASKING
+static PyObject *pylong_ulong_mask = NULL;
+static PyObject *pyint_zero = NULL;
+#endif
+
+/* If PY_STRUCT_FLOAT_COERCE is defined, the struct module will allow float
+  arguments for integer formats with a warning for backwards
+  compatibility. */
+
+#define PY_STRUCT_FLOAT_COERCE 1
+
+#ifdef PY_STRUCT_FLOAT_COERCE
+#define FLOAT_COERCE "integer argument expected, got float"
+#endif
+
+/* Native is default
+  If F_LE or F_BE is set, then alignment
+  information should not be used.
+*/
+#define F_LE      0x0100
+#define F_BE      0x0200
+#define F_BIT     0x0400
+#define F_PTR     0x0800
+#define F_CMPLX   0x1000
+#define F_STRUCT  0x2000
+#define F_ARRAY   0x4000
+#define F_FUNCPTR 0x8000
+#define F_BITMASK 0x00FF  /* storage in FLAG for bit-offset */
+
+#define F_IS_NATIVE(c) ((((const _formatcode *)(c))->flags & (F_LE||F_BE))==0)
+#define F_IS_LE(c) ((((const _formatcode *)(c))->flags & F_LE) == F_LE)
+#define F_IS_BE(c) ((((const _formatcode *)(c))->flags & F_BE) == F_BE)
+
+struct forward _formatcode;
+
+/* The translation function for each format character is table driven */
+typedef struct _formatdef {
+       char format;
+       Py_ssize_t size;
+       Py_ssize_t stdsize;
+       Py_ssize_t alignment;
+       PyObject* (*unpack)(const char *,
+                           const struct _formatdef *,
+                           const struct _formatcode *);
+       int (*pack)(char *, PyObject *,
+                   const struct _formatdef *,
+                   const struct _formatcode *);
+} formatdef;
+
+typedef struct _formatcode {
+       const struct _formatdef *fmtdef;  /* format information */
+       Py_ssize_t offset;                /* offset into the data area
+                                            relative to the start of
+                                            this structure */
+       Py_ssize_t size;                  /* size of the data implied */
+       char *name;                       /* field name of this code */
+       int flags;                        /* ISBIT, ISPTR, ISSTRUCT,
+                                            ISCMPLX, ISFUNCPTR, ISARRAY */
+       void *ptr;
+
+              /* several possibilities:
+
+               pointer to a format code     pointer, complex, array
+               pointer to a StructObject    struct, function pointer
+
+               in case of function pointer, the structure represents
+               the function arguments (last one represents return type).
+               */
+} formatcode;
+
+/* This format code has extra fields for shape information  but it is
+  binary compatible with the formatcode.
+*/
+
+typedef struct _arraycode {
+       formatcode code;
+       int ndims;
+       Py_ssize_t *shape;
+} arraycode;
+
+/* Struct object interface */
+
+typedef struct _structobject {
+       PyObject_HEAD
+       Py_ssize_t s_size;     /* The byte-size the data-string */
+       Py_ssize_t s_len;      /* Number of codes */
+       formatcode *s_codes;   /* Pointer to array of codes */
+       PyObject *s_format;    /* Python format string */
+       PyObject *weakreflist; /* List of weak references */
+} PyStructObject;
+
+
+typedef struct _fieldtupleobject {
+       PyTupleObject tup;
+       char **names;            /* array of strings with names of the fields */
+} PyFieldTupleObject;
+
+#define PyStruct_Check(op) PyObject_TypeCheck(op, &PyStructType)
+#define PyStruct_CheckExact(op) ((op)->ob_type == &PyStructType)
+
+#define PyFieldTuple_Check(op) PyObject_TypeCheck(op, &PyFieldTuple_Check)
+#define PyFieldTuple_CheckExact(op) ((op)->ob_type == &PyFieldTuple_Check)
+
+
+/* Exception */
+
+static PyObject *StructError;
+
+
+/* Define various structs to figure out the alignments of types */
+
+
+typedef struct { char c; short x; } st_short;
+typedef struct { char c; int x; } st_int;
+typedef struct { char c; long x; } st_long;
+typedef struct { char c; float x; } st_float;
+typedef struct { char c; double x; } st_double;
+typedef struct { char c; long double x;} st_longdouble;
+typedef struct { char c; void *x; } st_void_p;
+
+#define SHORT_ALIGN (sizeof(st_short) - sizeof(short))
+#define INT_ALIGN (sizeof(st_int) - sizeof(int))
+#define LONG_ALIGN (sizeof(st_long) - sizeof(long))
+#define FLOAT_ALIGN (sizeof(st_float) - sizeof(float))
+#define DOUBLE_ALIGN (sizeof(st_double) - sizeof(double))
+#define VOID_P_ALIGN (sizeof(st_void_p) - sizeof(void *))
+
+/* We can't support q and Q in native mode unless the compiler does;
+  in std mode, they're 8 bytes on all platforms. */
+#ifdef HAVE_LONG_LONG
+typedef struct { char c; PY_LONG_LONG x; } s_long_long;
+#define LONG_LONG_ALIGN (sizeof(s_long_long) - sizeof(PY_LONG_LONG))
+#endif
+
+/* Long double in native mode is platform dependent.
+  in std mode they're 16 bytes on all platforms
+ */
+#ifdef HAVE_LONG_DOUBLE
+typedef struct { char c; PY_LONG_LONG x; } s_long_double;
+#define LONG_DOUBLE_ALIGN (sizeof(s_long_double) - sizeof(long double))
+#endif
+
+#ifdef HAVE_C99_BOOL
+#define BOOL_TYPE _Bool
+typedef struct { char c; _Bool x; } s_bool;
+#define BOOL_ALIGN (sizeof(s_bool) - sizeof(BOOL_TYPE))
+#else
+#define BOOL_TYPE char
+#define BOOL_ALIGN 0
+#endif
+
+#define STRINGIFY(x)    #x
+
+#ifdef __powerc
+#pragma options align=reset
+#endif
+
+/* Helper to get a PyLongObject by hook or by crook.  Caller should decref. */
+
+static PyObject *
+get_pylong(PyObject *v)
+{
+       PyNumberMethods *m;
+
+       assert(v != NULL);
+       if (PyLong_Check(v)) {
+               Py_INCREF(v);
+               return v;
+       }
+       m = v->ob_type->tp_as_number;
+       if (m != NULL && m->nb_long != NULL) {
+               v = m->nb_long(v);
+               if (v == NULL)
+                       return NULL;
+               if (PyLong_Check(v))
+                       return v;
+               Py_DECREF(v);
+       }
+       PyErr_SetString(StructError,
+                       "cannot convert argument to long");
+       return NULL;
+}
+
+/* Helper routine to get a Python integer and raise the appropriate error
+  if it isn't one */
+
+static int
+get_long(PyObject *v, long *p)
+{
+       long x = PyInt_AsLong(v);
+       if (x == -1 && PyErr_Occurred()) {
+#ifdef PY_STRUCT_FLOAT_COERCE
+               if (PyFloat_Check(v)) {
+                       PyObject *o;
+                       int res;
+                       PyErr_Clear();
+                       if (PyErr_WarnEx(PyExc_DeprecationWarning, FLOAT_COERCE, 2) < 0)
+                               return -1;
+                       o = PyNumber_Int(v);
+                       if (o == NULL)
+                               return -1;
+                       res = get_long(o, p);
+                       Py_DECREF(o);
+                       return res;
+               }
+#endif
+               if (PyErr_ExceptionMatches(PyExc_TypeError))
+                       PyErr_SetString(StructError,
+                                       "required argument is not an integer");
+               return -1;
+       }
+       *p = x;
+       return 0;
+}
+
+
+/* Same, but handling unsigned long */
+
+static int
+get_ulong(PyObject *v, unsigned long *p)
+{
+       if (PyLong_Check(v)) {
+               unsigned long x = PyLong_AsUnsignedLong(v);
+               if (x == (unsigned long)(-1) && PyErr_Occurred())
+                       return -1;
+               *p = x;
+               return 0;
+       }
+       if (get_long(v, (long *)p) < 0)
+               return -1;
+       if (((long)*p) < 0) {
+               PyErr_SetString(StructError,
+                               "unsigned argument is < 0");
+               return -1;
+       }
+       return 0;
+}
+
+#ifdef HAVE_LONG_LONG
+
+/* Same, but handling native long long. */
+
+static int
+get_longlong(PyObject *v, PY_LONG_LONG *p)
+{
+       PY_LONG_LONG x;
+
+       v = get_pylong(v);
+       if (v == NULL)
+               return -1;
+       assert(PyLong_Check(v));
+       x = PyLong_AsLongLong(v);
+       Py_DECREF(v);
+       if (x == (PY_LONG_LONG)-1 && PyErr_Occurred())
+               return -1;
+       *p = x;
+       return 0;
+}
+
+/* Same, but handling native unsigned long long. */
+
+static int
+get_ulonglong(PyObject *v, unsigned PY_LONG_LONG *p)
+{
+       unsigned PY_LONG_LONG x;
+
+       v = get_pylong(v);
+       if (v == NULL)
+               return -1;
+       assert(PyLong_Check(v));
+       x = PyLong_AsUnsignedLongLong(v);
+       Py_DECREF(v);
+       if (x == (unsigned PY_LONG_LONG)-1 && PyErr_Occurred())
+               return -1;
+       *p = x;
+       return 0;
+}
+
+#endif
+
+#ifdef PY_STRUCT_OVERFLOW_MASKING
+
+/* Helper routine to get a Python integer and raise the appropriate error
+  if it isn't one */
+
+#define INT_OVERFLOW "struct integer overflow masking is deprecated"
+
+static int
+get_wrapped_long(PyObject *v, long *p)
+{
+       if (get_long(v, p) < 0) {
+               if (PyLong_Check(v) &&
+                   PyErr_ExceptionMatches(PyExc_OverflowError)) {
+                       PyObject *wrapped;
+                       long x;
+                       PyErr_Clear();
+#ifdef PY_STRUCT_FLOAT_COERCE
+                       if (PyFloat_Check(v)) {
+                               PyObject *o;
+                               int res;
+                               PyErr_Clear();
+                               if (PyErr_WarnEx(PyExc_DeprecationWarning, FLOAT_COERCE, 2) < 0)
+                                       return -1;
+                               o = PyNumber_Int(v);
+                               if (o == NULL)
+                                       return -1;
+                               res = get_wrapped_long(o, p);
+                               Py_DECREF(o);
+                               return res;
+                       }
+#endif
+                       if (PyErr_WarnEx(PyExc_DeprecationWarning, INT_OVERFLOW, 2) < 0)
+                               return -1;
+                       wrapped = PyNumber_And(v, pylong_ulong_mask);
+                       if (wrapped == NULL)
+                               return -1;
+                       x = (long)PyLong_AsUnsignedLong(wrapped);
+                       Py_DECREF(wrapped);
+                       if (x == -1 && PyErr_Occurred())
+                               return -1;
+                       *p = x;
+               } else {
+                       return -1;
+               }
+       }
+       return 0;
+}
+
+static int
+get_wrapped_ulong(PyObject *v, unsigned long *p)
+{
+       long x = (long)PyLong_AsUnsignedLong(v);
+       if (x == -1 && PyErr_Occurred()) {
+               PyObject *wrapped;
+               PyErr_Clear();
+#ifdef PY_STRUCT_FLOAT_COERCE
+               if (PyFloat_Check(v)) {
+                       PyObject *o;
+                       int res;
+                       PyErr_Clear();
+                       if (PyErr_WarnEx(PyExc_DeprecationWarning, FLOAT_COERCE, 2) < 0)
+                               return -1;
+                       o = PyNumber_Int(v);
+                       if (o == NULL)
+                               return -1;
+                       res = get_wrapped_ulong(o, p);
+                       Py_DECREF(o);
+                       return res;
+               }
+#endif
+               wrapped = PyNumber_And(v, pylong_ulong_mask);
+               if (wrapped == NULL)
+                       return -1;
+               if (PyErr_WarnEx(PyExc_DeprecationWarning, INT_OVERFLOW, 2) < 0) {
+                       Py_DECREF(wrapped);
+                       return -1;
+               }
+               x = (long)PyLong_AsUnsignedLong(wrapped);
+               Py_DECREF(wrapped);
+               if (x == -1 && PyErr_Occurred())
+                       return -1;
+       }
+       *p = (unsigned long)x;
+       return 0;
+}
+
+#define RANGE_ERROR(x, f, flag, mask) \
+       do { \
+               if (_range_error(f, flag) < 0) \
+                       return -1; \
+               else \
+                       (x) &= (mask); \
+       } while (0)
+
+#else
+
+#define get_wrapped_long get_long
+#define get_wrapped_ulong get_ulong
+#define RANGE_ERROR(x, f, flag, mask) return _range_error(f, flag)
+
+#endif
+
+/* Floating point helpers */
+
+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((unsigned char *)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((unsigned char *)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(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(StructError,
+                       "'%c' format requires 0 <= number <= %zu",
+                       f->format,
+                       ulargest);
+       else {
+               const Py_ssize_t largest = (Py_ssize_t)(ulargest >> 1);
+               PyErr_Format(StructError,
+                       "'%c' format requires %zd <= number <= %zd",
+                       f->format,
+                       ~ largest,
+                       largest);
+       }
+#ifdef PY_STRUCT_OVERFLOW_MASKING
+       {
+               PyObject *ptype, *pvalue, *ptraceback;
+               PyObject *msg;
+               int rval;
+               PyErr_Fetch(&ptype, &pvalue, &ptraceback);
+               assert(pvalue != NULL);
+               msg = PyObject_Str(pvalue);
+               Py_XDECREF(ptype);
+               Py_XDECREF(pvalue);
+               Py_XDECREF(ptraceback);
+               if (msg == NULL)
+                       return -1;
+               rval = PyErr_WarnEx(PyExc_DeprecationWarning,
+                                   PyString_AS_STRING(msg), 2);
+               Py_DECREF(msg);
+               if (rval == 0)
+                       return 0;
+       }
+#endif
+       return -1;
+}
+
+static PyObject *
+u_bit(const char *p, const formatdef *f, const formatcode *c)
+{
+       return NULL;
+}
+
+static int
+p_bit(char *p, PyObject *obj, const struct _formatdef *f,
+     const struct _formatcode *c)
+{
+       return 0;
+}
+
+
+static PyObject *
+u_byte(const char *p, const formatdef *f, const formatcode *c)
+{
+       return PyInt_FromLong((long) *(signed char *)p);
+}
+
+static int
+p_byte(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       long x;
+       if (get_long(v, &x) < 0)
+               return -1;
+       if (x < -128 || x > 127){
+               PyErr_SetString(StructError,
+                               "byte format requires -128 <= number <= 127");
+               return -1;
+       }
+       *p = (char)x;
+       return 0;
+}
+
+static PyObject *
+u_ubyte(const char *p, const formatdef *f, const formatcode *c)
+{
+       return PyInt_FromLong((long) *(unsigned char *)p);
+}
+
+
+static int
+p_ubyte(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       long x;
+       if (get_long(v, &x) < 0)
+               return -1;
+       if (x < 0 || x > 255){
+               PyErr_SetString(StructError,
+                               "ubyte format requires 0 <= number <= 255");
+               return -1;
+       }
+       *p = (char)x;
+       return 0;
+}
+
+
+static PyObject *
+u_char(const char *p, const formatdef *f, const formatcode *c)
+{
+       return PyString_FromStringAndSize(p, 1);
+}
+
+
+static int
+p_char(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       if (!PyString_Check(v) || PyString_Size(v) != 1) {
+               PyErr_SetString(StructError,
+                               "char format require string of length 1");
+               return -1;
+       }
+       *p = *PyString_AsString(v);
+       return 0;
+}
+
+
+/***************
+
+HELPER ROUTINES for big-endian un-packing
+
+******************/
+
+static PyObject *
+bu_int(const char *p, const formatdef *f)
+{
+       long x = 0;
+       Py_ssize_t i = f->stdsize;
+       const unsigned char *bytes = (const unsigned char *)p;
+       do {
+               x = (x<<8) | *bytes++;
+       } while (--i > 0);
+       /* Extend the sign bit. */
+       if (SIZEOF_LONG > f->size)
+               x |= -(x & (1L << ((8 * f->size) - 1)));
+       return PyInt_FromLong(x);
+}
+
+static PyObject *
+bu_uint(const char *p, const formatdef *f)
+{
+       unsigned long x = 0;
+       Py_ssize_t i = f->stdsize;
+       const unsigned char *bytes = (const unsigned char *)p;
+       do {
+               x = (x<<8) | *bytes++;
+       } while (--i > 0);
+       if (x <= LONG_MAX)
+               return PyInt_FromLong((long)x);
+       return PyLong_FromUnsignedLong(x);
+}
+
+static PyObject *
+bu_longlong(const char *p, const formatdef *f)
+{
+#ifdef HAVE_LONG_LONG
+       PY_LONG_LONG x = 0;
+       Py_ssize_t i = f->stdsize;
+       const unsigned char *bytes = (const unsigned char *)p;
+       do {
+               x = (x<<8) | *bytes++;
+       } while (--i > 0);
+       /* Extend the sign bit. */
+       if (SIZEOF_LONG_LONG > f->size)
+               x |= -(x & (1L << ((8 * f->size) - 1)));
+       if (x >= LONG_MIN && x <= LONG_MAX)
+               return PyInt_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long));
+       return PyLong_FromLongLong(x);
+#else
+       return _PyLong_FromByteArray((const unsigned char *)p,
+                                     8,
+                                     0, /* little-endian */
+                                     1  /* signed */);
+#endif
+}
+
+static PyObject *
+bu_ulonglong(const char *p, const formatdef *f)
+{
+#ifdef HAVE_LONG_LONG
+       unsigned PY_LONG_LONG x = 0;
+       Py_ssize_t i = f->stdsize;
+       const unsigned char *bytes = (const unsigned char *)p;
+       do {
+               x = (x<<8) | *bytes++;
+       } while (--i > 0);
+       if (x <= LONG_MAX)
+               return PyInt_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long));
+       return PyLong_FromUnsignedLongLong(x);
+#else
+       return _PyLong_FromByteArray((const unsigned char *)p,
+                                     8,
+                                     0, /* little-endian */
+                                     0  /* signed */);
+#endif
+}
+
+static PyObject *
+bu_float(const char *p, const formatdef *f)
+{
+       return unpack_float(p, 0);
+}
+
+static PyObject *
+bu_double(const char *p, const formatdef *f)
+{
+       return unpack_double(p, 0);
+}
+
+
+/***************
+
+HELPER ROUTINES for little-endian un-packing
+
+******************/
+
+
+static PyObject *
+lu_int(const char *p, const formatdef *f)
+{
+       long x = 0;
+       Py_ssize_t i = f->stdsize;
+       const unsigned char *bytes = (const unsigned char *)p;
+       do {
+               x = (x<<8) | bytes[--i];
+       } while (i > 0);
+       /* Extend the sign bit. */
+       if (SIZEOF_LONG > f->size)
+               x |= -(x & (1L << ((8 * f->size) - 1)));
+       return PyInt_FromLong(x);
+}
+
+static PyObject *
+lu_uint(const char *p, const formatdef *f)
+{
+       unsigned long x = 0;
+       Py_ssize_t i = f->stdsize;
+       const unsigned char *bytes = (const unsigned char *)p;
+       do {
+               x = (x<<8) | bytes[--i];
+       } while (i > 0);
+       if (x <= LONG_MAX)
+               return PyInt_FromLong((long)x);
+       return PyLong_FromUnsignedLong((long)x);
+}
+
+static PyObject *
+lu_longlong(const char *p, const formatdef *f)
+{
+#ifdef HAVE_LONG_LONG
+       PY_LONG_LONG x = 0;
+       Py_ssize_t i = f->stdsize;
+       const unsigned char *bytes = (const unsigned char *)p;
+       do {
+               x = (x<<8) | bytes[--i];
+       } while (i > 0);
+       /* Extend the sign bit. */
+       if (SIZEOF_LONG_LONG > f->size)
+               x |= -(x & (1L << ((8 * f->size) - 1)));
+       if (x >= LONG_MIN && x <= LONG_MAX)
+               return PyInt_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long));
+       return PyLong_FromLongLong(x);
+#else
+       return _PyLong_FromByteArray((const unsigned char *)p,
+                                     8,
+                                     1, /* little-endian */
+                                     1  /* signed */);
+#endif
+}
+
+static PyObject *
+lu_ulonglong(const char *p, const formatdef *f)
+{
+#ifdef HAVE_LONG_LONG
+       unsigned PY_LONG_LONG x = 0;
+       Py_ssize_t i = f->stdsize;
+       const unsigned char *bytes = (const unsigned char *)p;
+       do {
+               x = (x<<8) | bytes[--i];
+       } while (i > 0);
+       if (x <= LONG_MAX)
+               return PyInt_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long));
+       return PyLong_FromUnsignedLongLong(x);
+#else
+       return _PyLong_FromByteArray((const unsigned char *)p,
+                                     8,
+                                     1, /* little-endian */
+                                     0  /* signed */);
+#endif
+}
+
+static PyObject *
+lu_float(const char *p, const formatdef *f)
+{
+       return unpack_float(p, 1);
+}
+
+static PyObject *
+lu_double(const char *p, const formatdef *f)
+{
+       return unpack_double(p, 1);
+}
+
+
+/***************
+
+HELPER ROUTINES for big-endian packing
+
+******************/
+
+
+static int
+bp_int(char *p, PyObject *v, const formatdef *f)
+{
+       long x;
+       Py_ssize_t i;
+       if (get_wrapped_long(v, &x) < 0)
+               return -1;
+       i = f->stdsize;
+       if (i != SIZEOF_LONG) {
+               if ((i == 2) && (x < -32768 || x > 32767))
+                       RANGE_ERROR(x, f, 0, 0xffffL);
+#if (SIZEOF_LONG != 4)
+               else if ((i == 4) && (x < -2147483648L || x > 2147483647L))
+                       RANGE_ERROR(x, f, 0, 0xffffffffL);
+#endif
+#ifdef PY_STRUCT_OVERFLOW_MASKING
+               else if ((i == 1) && (x < -128 || x > 127))
+                       RANGE_ERROR(x, f, 0, 0xffL);
+#endif
+       }
+       do {
+               p[--i] = (char)x;
+               x >>= 8;
+       } while (i > 0);
+       return 0;
+}
+
+static int
+bp_uint(char *p, PyObject *v, const formatdef *f)
+{
+       unsigned long x;
+       Py_ssize_t i;
+       if (get_wrapped_ulong(v, &x) < 0)
+               return -1;
+       i = f->stdsize;
+       if (i != SIZEOF_LONG) {
+               unsigned long maxint = 1;
+               maxint <<= (unsigned long)(i * 8);
+               if (x >= maxint)
+                       RANGE_ERROR(x, f, 1, maxint - 1);
+       }
+       do {
+               p[--i] = (char)x;
+               x >>= 8;
+       } while (i > 0);
+       return 0;
+}
+
+static int
+bp_longlong(char *p, PyObject *v, const formatdef *f)
+{
+       int res;
+       v = get_pylong(v);
+       if (v == NULL)
+               return -1;
+       res = _PyLong_AsByteArray((PyLongObject *)v,
+                                 (unsigned char *)p,
+                                 8,
+                                 0, /* little_endian */
+                                 1  /* signed */);
+       Py_DECREF(v);
+       return res;
+}
+
+static int
+bp_ulonglong(char *p, PyObject *v, const formatdef *f)
+{
+       int res;
+       v = get_pylong(v);
+       if (v == NULL)
+               return -1;
+       res = _PyLong_AsByteArray((PyLongObject *)v,
+                                 (unsigned char *)p,
+                                 8,
+                                 0, /* little_endian */
+                                 0  /* signed */);
+       Py_DECREF(v);
+       return res;
+}
+
+static int
+bp_float(char *p, PyObject *v, const formatdef *f)
+{
+       double x = PyFloat_AsDouble(v);
+       if (x == -1 && PyErr_Occurred()) {
+               PyErr_SetString(StructError,
+                               "required argument is not a float");
+               return -1;
+       }
+       return _PyFloat_Pack4(x, (unsigned char *)p, 0);
+}
+
+static int
+bp_double(char *p, PyObject *v, const formatdef *f)
+{
+       double x = PyFloat_AsDouble(v);
+       if (x == -1 && PyErr_Occurred()) {
+               PyErr_SetString(StructError,
+                               "required argument is not a float");
+               return -1;
+       }
+       return _PyFloat_Pack8(x, (unsigned char *)p, 0);
+}
+
+
+/***************
+
+HELPER ROUTINES for little-endian un-packing
+
+******************/
+
+
+static int
+lp_int(char *p, PyObject *v, const formatdef *f)
+{
+       long x;
+       Py_ssize_t i;
+       if (get_wrapped_long(v, &x) < 0)
+               return -1;
+       i = f->stdsize;
+       if (i != SIZEOF_LONG) {
+               if ((i == 2) && (x < -32768 || x > 32767))
+                       RANGE_ERROR(x, f, 0, 0xffffL);
+#if (SIZEOF_LONG != 4)
+               else if ((i == 4) && (x < -2147483648L || x > 2147483647L))
+                       RANGE_ERROR(x, f, 0, 0xffffffffL);
+#endif
+#ifdef PY_STRUCT_OVERFLOW_MASKING
+               else if ((i == 1) && (x < -128 || x > 127))
+                       RANGE_ERROR(x, f, 0, 0xffL);
+#endif
+       }
+       do {
+               *p++ = (char)x;
+               x >>= 8;
+       } while (--i > 0);
+       return 0;
+}
+
+static int
+lp_uint(char *p, PyObject *v, const formatdef *f)
+{
+       unsigned long x;
+       Py_ssize_t i;
+       if (get_wrapped_ulong(v, &x) < 0)
+               return -1;
+       i = f->stdsize;
+       if (i != SIZEOF_LONG) {
+               unsigned long maxint = 1;
+               maxint <<= (unsigned long)(i * 8);
+               if (x >= maxint)
+                       RANGE_ERROR(x, f, 1, maxint - 1);
+       }
+       do {
+               *p++ = (char)x;
+               x >>= 8;
+       } while (--i > 0);
+       return 0;
+}
+
+static int
+lp_longlong(char *p, PyObject *v, const formatdef *f)
+{
+       int res;
+       v = get_pylong(v);
+       if (v == NULL)
+               return -1;
+       res = _PyLong_AsByteArray((PyLongObject*)v,
+                                 (unsigned char *)p,
+                                 8,
+                                 1, /* little_endian */
+                                 1  /* signed */);
+       Py_DECREF(v);
+       return res;
+}
+
+static int
+lp_ulonglong(char *p, PyObject *v, const formatdef *f)
+{
+       int res;
+       v = get_pylong(v);
+       if (v == NULL)
+               return -1;
+       res = _PyLong_AsByteArray((PyLongObject*)v,
+                                 (unsigned char *)p,
+                                 8,
+                                 1, /* little_endian */
+                                 0  /* signed */);
+       Py_DECREF(v);
+       return res;
+}
+
+static int
+lp_float(char *p, PyObject *v, const formatdef *f)
+{
+       double x = PyFloat_AsDouble(v);
+       if (x == -1 && PyErr_Occurred()) {
+               PyErr_SetString(StructError,
+                               "required argument is not a float");
+               return -1;
+       }
+       return _PyFloat_Pack4(x, (unsigned char *)p, 1);
+}
+
+static int
+lp_double(char *p, PyObject *v, const formatdef *f)
+{
+       double x = PyFloat_AsDouble(v);
+       if (x == -1 && PyErr_Occurred()) {
+               PyErr_SetString(StructError,
+                               "required argument is not a float");
+               return -1;
+       }
+       return _PyFloat_Pack8(x, (unsigned char *)p, 1);
+}
+
+
+
+static PyObject *
+u_short(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               short x;
+               memcpy((char *)&x, p, sizeof x);
+               return PyInt_FromLong((long)x);
+       }
+       else if F_IS_LE(c) {
+               return lu_int(p, f);
+       }
+       else {
+               return bu_int(p, f);
+       }
+}
+
+
+static int
+p_short(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+
+       if F_IS_NATIVE(c) {
+               long x;
+               short y;
+               if (get_long(v, &x) < 0)
+                       return -1;
+               if (x < SHRT_MIN || x > SHRT_MAX){
+                       PyErr_SetString(StructError,
+                                       "short format requires " STRINGIFY(SHRT_MIN)
+                                       " <= number <= " STRINGIFY(SHRT_MAX));
+                       return -1;
+               }
+               y = (short)x;
+               memcpy(p, (char *)&y, sizeof y);
+               return 0;
+       }
+       else if F_IS_LE(c) {
+               return lp_int(p, v, f);
+       }
+       else {
+               return bp_int(p, v, f);
+       }
+}
+
+
+static PyObject *
+u_ushort(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               unsigned short x;
+               memcpy((char *)&x, p, sizeof x);
+               return PyInt_FromLong((long)x);
+       }
+       else if F_IS_LE(c) {
+               return lu_uint(p, f);
+       }
+       else {
+               return bu_uint(p, f);
+       }
+}
+
+
+static int
+p_ushort(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+
+       if F_IS_NATIVE(c) {
+               long x;
+               unsigned short y;
+               if (get_long(v, &x) < 0)
+                       return -1;
+               if (x < 0 || x > USHRT_MAX){
+                       PyErr_SetString(StructError,
+                                       "short format requires "
+                                       "0 <= number <= " STRINGIFY(USHRT_MAX));
+                       return -1;
+               }
+               y = (unsigned short)x;
+               memcpy(p, (char *)&y, sizeof y);
+               return 0;
+       }
+       else if F_IS_LE(c) {
+               return lp_uint(p, v, f);
+       }
+       else {
+               return bp_uint(p, v, f);
+       }
+}
+
+static PyObject *
+u_int(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               int x;
+               memcpy((char *)&x, p, sizeof x);
+               return PyInt_FromLong((long)x);
+       }
+       else if F_IS_LE(c) {
+               return lu_int(p, f);
+       }
+       else {
+               return bu_int(p, f);
+       }
+}
+
+
+static int
+p_int(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               long x;
+               int y;
+               if (get_long(v, &x) < 0)
+                       return -1;
+               if (x < SHRT_MIN || x > SHRT_MAX){
+                       PyErr_SetString(StructError,
+                                       "int format requires " STRINGIFY(SHRT_MIN)
+                                       " <= number <= " STRINGIFY(SHRT_MAX));
+                       return -1;
+               }
+               y = (int)x;
+               memcpy(p, (char *)&y, sizeof y);
+               return 0;
+       }
+       else if F_IS_LE(c) {
+               return lp_int(p, v, f);
+       }
+       else {
+               return bp_int(p, v, f);
+       }
+}
+
+
+static PyObject *
+u_uint(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               unsigned int x;
+               memcpy((char *)&x, p, sizeof x);
+#if (SIZEOF_LONG > SIZEOF_INT)
+               return PyInt_FromLong((long)x);
+#else
+               if (x <= ((unsigned int)LONG_MAX))
+                       return PyInt_FromLong((long)x);
+               return PyLong_FromUnsignedLong((unsigned long)x);
+#endif
+       }
+       else if F_IS_LE(c) {
+               return lu_uint(p, f);
+       }
+       else {
+               return bu_uint(p, f);
+       }
+}
+
+
+static int
+p_uint(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+
+       if F_IS_NATIVE(c) {
+               unsigned long x;
+               unsigned int y;
+               if (get_ulong(v, &x) < 0)
+                       return _range_error(f, 1);
+               y = (unsigned int)x;
+#if (SIZEOF_LONG > SIZEOF_INT)
+               if (x > ((unsigned long)UINT_MAX))
+                       return _range_error(f, 1);
+#endif
+               memcpy(p, (char *)&y, sizeof y);
+               return 0;
+       }
+       else if F_IS_LE(c) {
+               return lp_uint(p, v, f);
+       }
+       else {
+               return bp_uint(p, v, f);
+       }
+}
+
+
+static PyObject *
+u_long(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               long x;
+               memcpy((char *)&x, p, sizeof x);
+               return PyInt_FromLong(x);
+       }
+       else if F_IS_LE(c) {
+               return lu_int(p, f);
+       }
+       else {
+               return bu_int(p, f);
+       }
+}
+
+
+static int
+p_long(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               long x;
+               if (get_long(v, &x) < 0)
+                       return -1;
+               memcpy(p, (char *)&x, sizeof x);
+               return 0;
+       }
+       else if F_IS_LE(c) {
+               return lp_int(p, v, f);
+       }
+       else {
+               return bp_int(p, v, f);
+       }
+}
+
+
+static PyObject *
+u_ulong(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               unsigned long x;
+               memcpy((char *)&x, p, sizeof x);
+               if (x <= LONG_MAX)
+                       return PyInt_FromLong((long) x);
+               return PyLong_FromUnsignedLong(x);
+       }
+       else if F_IS_LE(c) {
+               return lu_uint(p, f);
+       }
+       else {
+               return bu_uint(p, f);
+       }
+}
+
+
+static int
+p_ulong(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+
+       if F_IS_NATIVE(c) {
+               unsigned long x;
+               if (get_long(v, &x) < 0)
+                       return _range_error(f, 1);
+               memcpy(p, (char *)&x, sizeof x);
+               return 0;
+       }
+       else if F_IS_LE(c) {
+               return lp_uint(p, v, f);
+       }
+       else {
+               return bp_uint(p, v, f);
+       }
+}
+
+#ifndef HAVE_LONG_LONG
+static void
+_no_longlong(void)
+{
+       PyErr_Format(StructError, "native long-long not supported.");
+}
+#endif
+
+
+
+static PyObject *
+u_longlong(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+#ifdef HAVE_LONG_LONG
+               PY_LONG_LONG x;
+               memcpy((char *)&x, p, sizeof x);
+               if (x >= LONG_MIN && x <= LONG_MAX)
+                       return PyInt_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long));
+               return PyLong_FromLongLong(x);
+#else
+               _no_longlong();
+               return NULL;
+#endif
+       }
+       else if F_IS_LE(c) {
+               return lu_int(p, f);
+       }
+       else {
+               return bu_int(p, f);
+       }
+}
+
+
+static int
+p_longlong(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+#ifdef HAVE_LONG_LONG
+               PY_LONG_LONG x;
+               if (get_longlong(v, &x) < 0)
+                       return -1;
+               memcpy(p, (char *)&x, sizeof x);
+               return 0;
+#else
+               _no_longlong();
+               return -1;
+#endif
+       }
+       else if F_IS_LE(c) {
+               return lp_longlong(p, v, f);
+       }
+       else {
+               return bp_longlong(p, v, f);
+       }
+}
+
+
+static PyObject *
+u_ulonglong(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+#ifdef HAVE_LONG_LONG
+               unsigned PY_LONG_LONG x;
+               memcpy((char *)&x, p, sizeof x);
+               if (x <= LONG_MAX)
+                       return PyInt_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long));
+               return PyLong_FromUnsignedLongLong(x);
+#else
+               _no_longlong();
+               return NULL;
+#endif
+       }
+       else if F_IS_LE(c) {
+               return lu_ulonglong(p, f);
+       }
+       else {
+               return bu_ulonglong(p, f);
+       }
+}
+
+
+static int
+p_ulonglong(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+
+       if F_IS_NATIVE(c) {
+#ifdef HAVE_LONG_LONG
+               unsigned PY_LONG_LONG x;
+               if (get_ulonglong(v, &x) < 0)
+                       return -1;
+               memcpy(p, (char *)&x, sizeof x);
+               return 0;
+#else
+               _no_longlong();
+               return -1;
+#endif
+       }
+       else if F_IS_LE(c) {
+               return lp_ulonglong(p, v, f);
+       }
+       else {
+               return bp_ulonglong(p, v, f);
+       }
+}
+
+
+static PyObject *
+u_bool(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               BOOL_TYPE x;
+               memcpy((char *)&x, p, sizeof x);
+       }
+       else {
+               char x;
+               memcpy((char *)&x, p, sizeof x);
+       }
+       return PyBool_FromLong(x != 0);
+
+}
+
+
+static int
+p_bool(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               BOOL_TYPE y;
+               y = PyObject_IsTrue(v);
+               memcpy(p, (char *)&y, sizeof y);
+       }
+       else {
+               char y;
+               y = PyObject_IsTrue(v);
+               memcpy(p, (char *)&y, sizeof y);
+       }
+       return 0;
+
+}
+
+
+static PyObject *
+u_float(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               float x;
+               memcpy((char *)&x, p, sizeof x);
+               return PyFloat_FromDouble((double)x);
+       }
+       else {
+               return unpack_float(p, F_IS_LE(c));
+       }
+}
+
+
+static int
+p_float(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       double xi;
+
+       xi = PyFloat_AsDouble(v);
+       if (xi == -1 && PyErr_Occurred()) {
+               PyErr_SetString(StructError,
+                               "required argument is not a float");
+               return -1;
+       }
+       if F_IS_NATIVE(c) {
+               float x = (float) xi;
+               memcpy(p, (char *)&x, sizeof x);
+               return 0;
+       }
+       else {
+               return _PyFloat_Pack4(x, (unsigned char *)p, F_IS_LE(c));
+       }
+}
+
+
+static PyObject *
+u_double(const char *p, const formatdef *f, const formatcode *c)
+{
+       if F_IS_NATIVE(c) {
+               double x;
+               memcpy((char *)&x, p, sizeof x);
+               return PyFloat_FromDouble((double)x);
+       }
+       else {
+               return unpack_double(p, F_IS_LE(c));
+       }
+}
+
+static int
+p_double(char *p, PyObject *v, const formatdef *f, const formatcode *c)
+{
+       double x;
+
+       x = PyFloat_AsDouble(v);
+       if (x == -1 && PyErr_Occurred()) {
+               PyErr_SetString(StructError,
+                               "required argument is not a float");
+               return -1;
+       }
+       if F_IS_NATIVE(c) {
+               memcpy(p, (char *)&x, sizeof x);
+               return 0;
+       }
+       else {
+               return _PyFloat_Pack8(x, (unsigned char *)p, F_IS_LE(c));
+       }
+}
+
+
+/* There is only one un-packing and packing table,
+  to allow switching of the endian-ness within a struct
+  native, little-endian, and big-endian packing
+  are handled by these functions based on the
+  format-code flag.  Whether or not to use alignment is
+  also handled by the flag.  Alignment is
+  used only in native mode (no flag set).
+*/
+static formatdef general_table[] = {
+       {'x',   sizeof(char),      1,  0,            NULL,         NULL},
+       {'t',   0,                 0,  0,            u_bit,        p_bit},
+       {'b',   sizeof(char),      1,  0,            u_byte,       p_byte},
+       {'B',   sizeof(char),      1,  0,            u_ubyte,      p_ubyte},
+       {'c',   sizeof(char),      1,  0,            u_char,       p_char},
+       {'u',   2,                 2,  0,            u_ucs2,       p_ucs2},
+       {'w',   4,                 4,  0,            u_ucs4,       p_ucs4},
+       {'s',   sizeof(char),      1,  0,            NULL,         NULL},
+       {'p',   sizeof(char),      1,  0,            NULL,         NULL},
+       {'h',   sizeof(short),     2,  SHORT_ALIGN,  u_short,      p_short},
+       {'H',   sizeof(short),     2,  SHORT_ALIGN,  u_ushort,     p_ushort},
+       {'i',   sizeof(int),       4,  INT_ALIGN,    u_int,        p_int},
+       {'I',   sizeof(int),       4,  INT_ALIGN,    u_uint,       p_uint},
+       {'l',   sizeof(long),      4,  LONG_ALIGN,   u_long,       p_long},
+       {'L',   sizeof(long),      4,  LONG_ALIGN,   u_ulong,      p_ulong},
+       {'q',   0,                 8,  0,            u_longlong,   p_longlong},
+       {'Q',   0,                 8,  0,            u_ulonglong,  p_ulonglong},
+       {'?',   sizeof(BOOL_TYPE), 1,  BOOL_ALIGN,   u_bool,       p_bool},
+       {'f',   sizeof(float),     4,  FLOAT_ALIGN,  u_float,      p_float},
+       {'d',   sizeof(double),    8,  DOUBLE_ALIGN, u_double,     p_double},
+       {'g',   0,                 16, 0,            u_longdouble, p_longdouble},
+       {'Z',   0,                 0,  0,            u_cmplx,      p_cmplx},
+       {'&',   sizeof(void*),     -1, VOID_P_ALIGN, u_gptr,       p_gptr},
+       {'(',   0,                 -1, 0,            u_array,      p_array},
+       {'P',   sizeof(void*),     -1, VOID_P_ALIGN, u_void_p,     p_void_p},
+       {'O',   sizeof(PyObject*), -1, VOID_P_ALIGN, u_object_p,   p_object_p},
+       {'T',   0,                 -1, 0,            u_struct,     p_struct},
+       {'X',   sizeof(void*),     -1, VOID_P_ALIGN, u_funcptr,    p_funcptr},
+       {0}
+};
+
+
+/* Get the table entry for a format code */
+
+static const formatdef *
+getentry(int c, const formatdef *f)
+{
+       for (; f->format != '\0'; f++) {
+               if (f->format == c) {
+                       return f;
+               }
+       }
+       PyErr_SetString(StructError, "bad char in struct format");
+       return NULL;
+}
+
+
+/* Align a size according to a format code */
+
+static int
+align(Py_ssize_t size, char c, const formatdef *e)
+{
+       if (e->format == c) {
+               if (e->alignment) {
+                       size = ((size + e->alignment - 1)
+                               / e->alignment)
+                               * e->alignment;
+               }
+       }
+       return size;
+}
+
+
+/* calculate the size of a format string */
+
+static int
+prepare_s(PyStructObject *self)
+{
+       const formatdef *f;
+       const formatdef *e;
+       formatcode *codes;
+
+       const char *s;
+       const char *fmt;
+       char c;
+       Py_ssize_t size, len, num, itemsize, x;
+
+       fmt = PyString_AS_STRING(self->s_format);
+
+       f = whichtable((char **)&fmt);
+
+       s = fmt;
+       size = 0;
+       len = 0;
+       while ((c = *s++) != '\0') {
+               if (isspace(Py_CHARMASK(c)))
+                       continue;
+               if ('0' <= c && c <= '9') {
+                       num = c - '0';
+                       while ('0' <= (c = *s++) && c <= '9') {
+                               x = num*10 + (c - '0');
+                               if (x/10 != num) {
+                                       PyErr_SetString(
+                                               StructError,
+                                               "overflow in item count");
+                                       return -1;
+                               }
+                               num = x;
+                       }
+                       if (c == '\0')
+                               break;
+               }
+               else
+                       num = 1;
+
+               e = getentry(c, f);
+               if (e == NULL)
+                       return -1;
+
+               switch (c) {
+                       case 's': /* fall through */
+                       case 'p': len++; break;
+                       case 'x': break;
+                       default: len += num; break;
+               }
+
+               itemsize = e->size;
+               size = align(size, c, e);
+               x = num * itemsize;
+               size += x;
+               if (x/itemsize != num || size < 0) {
+                       PyErr_SetString(StructError,
+                                       "total struct size too long");
+                       return -1;
+               }
+       }
+
+       self->s_size = size;
+       self->s_len = len;
+       codes = PyMem_MALLOC((len + 1) * sizeof(formatcode));
+       if (codes == NULL) {
+               PyErr_NoMemory();
+               return -1;
+       }
+       self->s_codes = codes;
+
+       s = fmt;
+       size = 0;
+       while ((c = *s++) != '\0') {
+               if (isspace(Py_CHARMASK(c)))
+                       continue;
+               if ('0' <= c && c <= '9') {
+                       num = c - '0';
+                       while ('0' <= (c = *s++) && c <= '9')
+                               num = num*10 + (c - '0');
+                       if (c == '\0')
+                               break;
+               }
+               else
+                       num = 1;
+
+               e = getentry(c, f);
+
+               size = align(size, c, e);
+               if (c == 's' || c == 'p') {
+                       codes->offset = size;
+                       codes->size = num;
+                       codes->fmtdef = e;
+                       codes++;
+                       size += num;
+               } else if (c == 'x') {
+                       size += num;
+               } else {
+                       while (--num >= 0) {
+                               codes->offset = size;
+                               codes->size = e->size;
+                               codes->fmtdef = e;
+                               codes++;
+                               size += e->size;
+                       }
+               }
+       }
+       codes->fmtdef = NULL;
+       codes->offset = size;
+       codes->size = 0;
+
+       return 0;
+}
+
+static PyObject *
+s_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+       PyObject *self;
+
+       assert(type != NULL && type->tp_alloc != NULL);
+
+       self = type->tp_alloc(type, 0);
+       if (self != NULL) {
+               PyStructObject *s = (PyStructObject*)self;
+               Py_INCREF(Py_None);
+               s->s_format = Py_None;
+               s->s_codes = NULL;
+               s->s_size = -1;
+               s->s_len = -1;
+       }
+       return self;
+}
+
+static int
+s_init(PyObject *self, PyObject *args, PyObject *kwds)
+{
+       PyStructObject *soself = (PyStructObject *)self;
+       PyObject *o_format = NULL;
+       int ret = 0;
+       static char *kwlist[] = {"format", 0};
+
+       assert(PyStruct_Check(self));
+
+       if (!PyArg_ParseTupleAndKeywords(args, kwds, "S:Struct", kwlist,
+                                        &o_format))
+               return -1;
+
+       Py_INCREF(o_format);
+       Py_XDECREF(soself->s_format);
+       soself->s_format = o_format;
+
+       ret = prepare_s(soself);
+       return ret;
+}
+
+static void
+s_dealloc(PyStructObject *s)
+{
+       if (s->weakreflist != NULL)
+               PyObject_ClearWeakRefs((PyObject *)s);
+       if (s->s_codes != NULL) {
+               PyMem_FREE(s->s_codes);
+       }
+       Py_XDECREF(s->s_format);
+       s->ob_type->tp_free((PyObject *)s);
+}
+
+static PyObject *
+s_unpack_internal(PyStructObject *soself, char *startfrom) {
+       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++) {
+               PyObject *v;
+               const formatdef *e = code->fmtdef;
+               const char *res = startfrom + code->offset;
+               if (e->format == 's') {
+                       v = PyString_FromStringAndSize(res, code->size);
+               } else if (e->format == 'p') {
+                       Py_ssize_t n = *(unsigned char*)res;
+                       if (n >= code->size)
+                               n = code->size - 1;
+                       v = PyString_FromStringAndSize(res + 1, n);
+               } else {
+                       v = e->unpack(res, e);
+               }
+               if (v == NULL)
+                       goto fail;
+               PyTuple_SET_ITEM(result, i++, v);
+       }
+
+       return result;
+fail:
+       Py_DECREF(result);
+       return NULL;
+}
+
+
+PyDoc_STRVAR(s_unpack__doc__,
+"S.unpack(str) -> (v1, v2, ...)\n\
+\n\
+Return tuple containing values unpacked according to this Struct's format.\n\
+Requires len(str) == self.size. See struct.__doc__ for more on format\n\
+strings.");
+
+static PyObject *
+s_unpack(PyObject *self, PyObject *inputstr)
+{
+       PyStructObject *soself = (PyStructObject *)self;
+       assert(PyStruct_Check(self));
+       assert(soself->s_codes != NULL);
+       if (inputstr == NULL || !PyString_Check(inputstr) ||
+               PyString_GET_SIZE(inputstr) != soself->s_size) {
+               PyErr_Format(StructError,
+                       "unpack requires a string argument of length %zd",
+                       soself->s_size);
+               return NULL;
+       }
+       return s_unpack_internal(soself, PyString_AS_STRING(inputstr));
+}
+
+PyDoc_STRVAR(s_unpack_from__doc__,
+"S.unpack_from(buffer[, offset]) -> (v1, v2, ...)\n\
+\n\
+Return tuple containing values unpacked according to this Struct's format.\n\
+Unlike unpack, unpack_from can unpack values from any object supporting\n\
+the buffer API, not just str. Requires len(buffer[offset:]) >= self.size.\n\
+See struct.__doc__ for more on format strings.");
+
+static PyObject *
+s_unpack_from(PyObject *self, PyObject *args, PyObject *kwds)
+{
+       static char *kwlist[] = {"buffer", "offset", 0};
+#if (PY_VERSION_HEX < 0x02050000)
+       static char *fmt = "z#|i:unpack_from";
+#else
+       static char *fmt = "z#|n:unpack_from";
+#endif
+       Py_ssize_t buffer_len = 0, offset = 0;
+       char *buffer = NULL;
+       PyStructObject *soself = (PyStructObject *)self;
+       assert(PyStruct_Check(self));
+       assert(soself->s_codes != NULL);
+
+       if (!PyArg_ParseTupleAndKeywords(args, kwds, fmt, kwlist,
+                                        &buffer, &buffer_len, &offset))
+               return NULL;
+
+       if (buffer == NULL) {
+               PyErr_Format(StructError,
+                       "unpack_from requires a buffer argument");
+               return NULL;
+       }
+
+       if (offset < 0)
+               offset += buffer_len;
+
+       if (offset < 0 || (buffer_len - offset) < soself->s_size) {
+               PyErr_Format(StructError,
+                       "unpack_from requires a buffer of at least %zd bytes",
+                       soself->s_size);
+               return NULL;
+       }
+       return s_unpack_internal(soself, buffer + offset);
+}
+
+
+/*
+ * 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 string.  The caller must insure
+ * 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 *args, int offset, char* buf)
+{
+       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++) {
+               Py_ssize_t n;
+               PyObject *v = PyTuple_GET_ITEM(args, i++);
+               const formatdef *e = code->fmtdef;
+               char *res = buf + code->offset;
+               if (e->format == 's') {
+                       if (!PyString_Check(v)) {
+                               PyErr_SetString(StructError,
+                                               "argument for 's' must be a string");
+                               return -1;
+                       }
+                       n = PyString_GET_SIZE(v);
+                       if (n > code->size)
+                               n = code->size;
+                       if (n > 0)
+                               memcpy(res, PyString_AS_STRING(v), n);
+               } else if (e->format == 'p') {
+                       if (!PyString_Check(v)) {
+                               PyErr_SetString(StructError,
+                                               "argument for 'p' must be a string");
+                               return -1;
+                       }
+                       n = PyString_GET_SIZE(v);
+                       if (n > (code->size - 1))
+                               n = code->size - 1;
+                       if (n > 0)
+                               memcpy(res + 1, PyString_AS_STRING(v), n);
+                       if (n > 255)
+                               n = 255;
+                       *res = Py_SAFE_DOWNCAST(n, Py_ssize_t, unsigned char);
+               } else {
+                       if (e->pack(res, v, e) < 0) {
+                               if (PyLong_Check(v) && PyErr_ExceptionMatches(PyExc_OverflowError))
+                                       PyErr_SetString(StructError,
+                                                       "long too large to convert to int");
+                               return -1;
+                       }
+               }
+       }
+
+       /* Success */
+       return 0;
+}
+
+
+PyDoc_STRVAR(s_pack__doc__,
+"S.pack(v1, v2, ...) -> string\n\
+\n\
+Return a string containing values v1, v2, ... packed according to this\n\
+Struct's format. See struct.__doc__ for more on format strings.");
+
+static PyObject *
+s_pack(PyObject *self, PyObject *args)
+{
+       PyStructObject *soself;
+       PyObject *result;
+
+       /* Validate arguments. */
+       soself = (PyStructObject *)self;
+       assert(PyStruct_Check(self));
+       assert(soself->s_codes != NULL);
+       if (PyTuple_GET_SIZE(args) != soself->s_len)
+       {
+               PyErr_Format(StructError,
+                       "pack requires exactly %zd arguments", soself->s_len);
+               return NULL;
+       }
+
+       /* Allocate a new string */
+       result = PyString_FromStringAndSize((char *)NULL, soself->s_size);
+       if (result == NULL)
+               return NULL;
+
+       /* Call the guts */
+       if ( s_pack_internal(soself, args, 0, PyString_AS_STRING(result)) != 0 ) {
+               Py_DECREF(result);
+               return NULL;
+       }
+
+       return result;
+}
+
+PyDoc_STRVAR(s_pack_into__doc__,
+"S.pack_into(buffer, offset, v1, v2, ...)\n\
+\n\
+Pack the values v1, v2, ... according to this Struct's format, write \n\
+the packed bytes into the writable buffer buf starting at offset.  Note\n\
+that the offset is not an optional argument.  See struct.__doc__ for \n\
+more on format strings.");
+
+static PyObject *
+s_pack_into(PyObject *self, PyObject *args)
+{
+       PyStructObject *soself;
+       char *buffer;
+       Py_ssize_t buffer_len, offset;
+
+       /* Validate arguments.  +1 is for the first arg as buffer. */
+       soself = (PyStructObject *)self;
+       assert(PyStruct_Check(self));
+       assert(soself->s_codes != NULL);
+       if (PyTuple_GET_SIZE(args) != (soself->s_len + 2))
+       {
+               PyErr_Format(StructError,
+                            "pack_into requires exactly %zd arguments",
+                            (soself->s_len + 2));
+               return NULL;
+       }
+
+       /* Extract a writable memory buffer from the first argument */
+       if ( PyObject_AsWriteBuffer(PyTuple_GET_ITEM(args, 0),
+                                                               (void**)&buffer, &buffer_len) == -1 ) {
+               return NULL;
+       }
+       assert( buffer_len >= 0 );
+
+       /* Extract the offset from the first argument */
+       offset = PyInt_AsSsize_t(PyTuple_GET_ITEM(args, 1));
+
+       /* Support negative offsets. */
+       if (offset < 0)
+               offset += buffer_len;
+
+       /* Check boundaries */
+       if (offset < 0 || (buffer_len - offset) < soself->s_size) {
+               PyErr_Format(StructError,
+                            "pack_into requires a buffer of at least %zd bytes",
+                            soself->s_size);
+               return NULL;
+       }
+
+       /* Call the guts */
+       if ( s_pack_internal(soself, args, 2, buffer + offset) != 0 ) {
+               return NULL;
+       }
+
+       Py_RETURN_NONE;
+}
+
+static PyObject *
+s_get_format(PyStructObject *self, void *unused)
+{
+       Py_INCREF(self->s_format);
+       return self->s_format;
+}
+
+static PyObject *
+s_get_size(PyStructObject *self, void *unused)
+{
+       return PyInt_FromSsize_t(self->s_size);
+}
+
+static PyObject *
+s_get_numcodes(PyStructObject *self, void *unused)
+{
+       return PyInt_FromSsize_t(self->s_len);
+}
+
+/* List of functions */
+
+static struct PyMethodDef s_methods[] = {
+       {"pack",        s_pack,         METH_VARARGS, s_pack__doc__},
+       {"pack_into",   s_pack_into,    METH_VARARGS, s_pack_into__doc__},
+       {"unpack",      s_unpack,       METH_O, s_unpack__doc__},
+       {"unpack_from", (PyCFunction)s_unpack_from, METH_KEYWORDS,
+                       s_unpack_from__doc__},
+       {NULL,   NULL}          /* sentinel */
+};
+
+PyDoc_STRVAR(s__doc__, "Compiled struct object");
+
+#define OFF(x) offsetof(PyStructObject, x)
+
+static PyGetSetDef s_getsetlist[] = {
+       {"format", (getter)s_get_format, (setter)NULL, "struct format string", NULL},
+       {"size", (getter)s_get_size, (setter)NULL, "struct size in bytes", NULL},
+       {"numcodes",  (getter)s_get_len, (setter)NULL, "number of elements in struct", NULL},
+       {NULL} /* sentinel */
+};
+
+static
+PyTypeObject PyStructType = {
+       PyObject_HEAD_INIT(NULL)
+       0,
+       "Struct",
+       sizeof(PyStructObject),
+       0,
+       (destructor)s_dealloc,  /* tp_dealloc */
+       0,                                      /* tp_print */
+       0,                                      /* tp_getattr */
+       0,                                      /* tp_setattr */
+       0,                                      /* tp_compare */
+       0,                                      /* tp_repr */
+       0,                                      /* tp_as_number */
+       0,                                      /* tp_as_sequence */
+       0,                                      /* tp_as_mapping */
+       0,                                      /* tp_hash */
+       0,                                      /* tp_call */
+       0,                                      /* tp_str */
+       PyObject_GenericGetAttr,        /* tp_getattro */
+       PyObject_GenericSetAttr,        /* tp_setattro */
+       0,                                      /* tp_as_buffer */
+       Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+       s__doc__,                       /* tp_doc */
+       0,                                      /* tp_traverse */
+       0,                                      /* tp_clear */
+       0,                                      /* tp_richcompare */
+       offsetof(PyStructObject, weakreflist),  /* tp_weaklistoffset */
+       0,                                      /* tp_iter */
+       0,                                      /* tp_iternext */
+       s_methods,                      /* tp_methods */
+       NULL,                           /* tp_members */
+       s_getsetlist,           /* tp_getset */
+       0,                              /* tp_base */
+       0,                                      /* tp_dict */
+       0,                                      /* tp_descr_get */
+       0,                                      /* tp_descr_set */
+       0,                                      /* tp_dictoffset */
+       s_init,                         /* tp_init */
+       PType_GenericAlloc,            /* tp_alloc */
+       s_new,                          /* tp_new */
+       PyObject_Del,           /* tp_free */
+};
+
+
+static
+PyTypeObject PyFieldTupleType = {
+       PyObject_HEAD_INIT(NULL)
+       0,
+       "fieldtuple",
+       sizeof(PyFieldTupleObject),
+       0,
+       (destructor)f_dealloc,                 /* tp_dealloc */
+       0,                                      /* tp_print */
+       0,                                      /* tp_getattr */
+       0,                                      /* tp_setattr */
+       0,                                      /* tp_compare */
+       0,                                      /* tp_repr */
+       0,                                      /* tp_as_number */
+       0,                                      /* tp_as_sequence */
+       &f_as_mapping,                          /* tp_as_mapping */
+       0,                                      /* tp_hash */
+       0,                                      /* tp_call */
+       0,                                      /* tp_str */
+       PyObject_GenericGetAttr,                /* tp_getattro */
+       PyObject_GenericSetAttr,                /* tp_setattro */
+       0,                                      /* tp_as_buffer */
+       Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+       f__doc__,                               /* tp_doc */
+       0,                                      /* tp_traverse */
+       0,                                      /* tp_clear */
+       0,                                      /* tp_richcompare */
+       0,                                      /* tp_weaklistoffset */
+       0,                                      /* tp_iter */
+       0,                                      /* tp_iternext */
+       0,                                      /* tp_methods */
+       NULL,                                   /* tp_members */
+       0,                                      /* tp_getset */
+       &PyTuple_Type,                          /* tp_base */
+       0,                                      /* tp_dict */
+       0,                                      /* tp_descr_get */
+       0,                                      /* tp_descr_set */
+       0,                                      /* tp_dictoffset */
+       f_init,                         /* tp_init */
+       PyType_GenericAlloc,            /* tp_alloc */
+       f_new,                          /* tp_new */
+       PyObject_Del,                   /* tp_free */
+};
+
+/* Module initialization */
+
+PyMODINIT_FUNC
+init_struct(void)
+{
+       PyObject *m = Py_InitModule("_struct", NULL);
+       if (m == NULL)
+               return;
+
+       /* fill in LONG_LONG and LONG_DOUBLE table-entries if needed */
+       {
+               const formatdef *entry;
+               const formatdef *table;
+
+               table = (const formatdef *)general_table;
+#ifdef HAVE_LONG_LONG
+
+               entry = getentry('q',table);
+               entry->size = sizeof(PY_LONG_LONG);
+               entry->alignment = LONG_LONG_ALIGN;
+
+               entry = getentry('Q',table);
+               entry->size = sizeof(PY_LONG_LONG);
+               entry->alignment = LONG_LONG_ALIGN;
+#endif
+
+#ifdef HAVE_LONG_DOUBLE
+               entry = getentry('g',table);
+               entry->size = sizeof(long double);
+               entry->alignment = LONG_DOUBLE_ALIGN;
+#endif
+       }
+
+       PyStructType.ob_type = &PyType_Type;
+       if (PyType_Ready(&PyStructType) < 0)
+               return;
+
+       PyFieldTupleType.ob_type = &PyType_Type;
+       if (PyType_Read(&PyFieldTupleType) < 0)
+               return;
+
+#ifdef PY_STRUCT_OVERFLOW_MASKING
+       if (pyint_zero == NULL) {
+               pyint_zero = PyInt_FromLong(0);
+               if (pyint_zero == NULL)
+                       return;
+       }
+       if (pylong_ulong_mask == NULL) {
+ #if (SIZEOF_LONG == 4)
+               pylong_ulong_mask = PyLong_FromString("FFFFFFFF", NULL, 16);
+ #else
+               pylong_ulong_mask = PyLong_FromString("FFFFFFFFFFFFFFFF", NULL, 16);
+ #endif
+               if (pylong_ulong_mask == NULL)
+                       return;
+       }
+#endif
+
+
+       /* Add some symbolic constants to the module */
+       if (StructError == NULL) {
+               StructError = PyErr_NewException("struct.error", NULL, NULL);
+               if (StructError == NULL)
+                       return;
+       }
+
+       Py_INCREF(StructError);
+       PyModule_AddObject(m, "error", StructError);
+
+       Py_INCREF((PyObject*)&PyStructType);
+       PyModule_AddObject(m, "Struct", (PyObject*)&PyStructType);
+
+       PyModule_AddIntConstant(m, "_PY_STRUCT_RANGE_CHECKING", 1);
+#ifdef PY_STRUCT_OVERFLOW_MASKING
+       PyModule_AddIntConstant(m, "_PY_STRUCT_OVERFLOW_MASKING", 1);
+#endif
+#ifdef PY_STRUCT_FLOAT_COERCE
+       PyModule_AddIntConstant(m, "_PY_STRUCT_FLOAT_COERCE", 1);
+#endif
+
+}
+
+
+


Property changes on: branches/py3k/Modules/_struct.c
___________________________________________________________________
Name: svn:keywords
   + Id
Name: svn:eol-style
   + native



More information about the Numpy-svn mailing list