Pretty much rewritten to fulfull several long-standing wishes:

-- The whole implementation is now more table-driven.

-- Unsigned integers.  Format characters 'B', 'H', 'I' and 'L'
mean unsigned byte, short, int and long.  For 'I' and 'L', the return
value is a Python long integer if a Python plain integer can't
represent the required range (note: this is dependent on the size of
the relevant C types only, not of the sign of the actual value).

-- A new format character 's' packs/unpacks a string.  When given a
count prefix, this is the size of the string, not a repeat count like
for the other format characters; e.g. '10s' means a single 10-byte
string, while '10c' means 10 characters.  For packing, the string is
truncated or padded with null bytes as appropriate to make it fit.
For unpacking, the resulting string always has exactly the specified
number of bytes.  As a special case, '0s' means a single, empty
string (while '0c' means 0 characters).

-- Various byte order options.  The first character of the format
string determines the byte order, size and alignment, as follows:

First character		Byte order		size and alignment

	'@'		native			native
	'='		native			standard
	'<'		little-endian		standard
	'>'		big-endian		standard
	'!'		network (= big-endian)	standard

If the first character is not one of these, '@' is assumed.

Native byte order is big-endian or little-endian, depending on the
host system (e.g. Motorola and Sun are big-endian; Intel and DEC are
little-endian).

Native size and alignment are determined using the C compiler's sizeof
expression.  This is always combined with native byte order.

Standard size and alignment are as follows: no alignment is required
for any type (so you have to use pad bytes); short is 2 bytes; int and
long are 4 bytes.  In this mode, there is no support for float and
double.

Note the difference between '@' and '=': both use native byte order,
but the size and alignment of the latter is standardized.

The form '!' is available for those poor souls who can't remember
whether network byte order is big-endian or little-endian.

There is no way to indicate non-native byte order (i.e. force
byte-swapping); use the appropriate choice of '<' or '>'.

1 files changed, 572 insertions, 226 deletions

diff --git a/Modules/structmodule.c b/Modules/structmodule.c
index f9eb6b5..cfbd2a6 100644
--- a/Modules/structmodule.c
+++ b/Modules/structmodule.c
@@ -31,8 +31,16 @@ PERFORMANCE OF THIS SOFTWARE.
 
 /* struct module -- pack values into and (out of) strings */
 
+/* New version supporting byte order, alignment and size options,
+   character strings, and unsigned numbers */
+
 #include "Python.h"
 
+#include <limits.h>
+
+
+/* Exception */
+
 static PyObject *StructError;
 
 
@@ -65,34 +73,495 @@ typedef struct { char c; double x; } s_double;
 #endif
 
 
-/* Align a size according to a format code */
+/* Helper routine to turn a (signed) long into an unsigned long */
+/* XXX This assumes 2's complement arithmetic */
+
+static PyObject *
+make_ulong(x)
+	long x;
+{
+	PyObject *v = PyLong_FromLong(x);
+	if (x < 0 && v != NULL) {
+		static PyObject *offset = NULL;
+		PyObject *result = NULL;
+		if (offset == NULL) {
+			PyObject *one = PyLong_FromLong(1L);
+			PyObject *shiftcount =
+				PyLong_FromLong(8 * sizeof(long));
+			if (one == NULL || shiftcount == NULL)
+				goto bad;
+			offset = PyNumber_Lshift(one, shiftcount);
+		  bad:
+			Py_XDECREF(one);
+			Py_XDECREF(shiftcount);
+			if (offset == NULL)
+				goto finally;
+		}
+		result = PyNumber_Add(v, offset);
+	  finally:
+		Py_DECREF(v);
+		return result;
+	}
+	else
+		return v;
+}
+
+/* Helper routine to get a Python integer and raise the appropriate error
+   if it isn't one */
 
 static int
-align(size, c)
+get_long(v, p)
+	PyObject *v;
+	long *p;
+{
+	long x = PyInt_AsLong(v);
+	if (x == -1 && PyErr_Occurred()) {
+		if (PyErr_Occurred() == PyExc_TypeError)
+			PyErr_SetString(StructError,
+					"required argument is not an integer");
+		return -1;
+	}
+	*p = x;
+	return 0;
+}
+
+
+/* The translation function for each format character is table driven */
+
+typedef struct _formatdef {
+	char format;
 	int size;
+	int alignment;
+	PyObject* (*unpack) Py_PROTO((const char *,
+				      const struct _formatdef *));
+	int (*pack) Py_PROTO((char *,
+			      PyObject *,
+			      const struct _formatdef *));
+} formatdef;
+
+static PyObject *
+nu_char(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	return PyString_FromStringAndSize(p, 1);
+}
+
+static PyObject *
+nu_byte(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	return PyInt_FromLong((long) *(signed char *)p);
+}
+
+static PyObject *
+nu_ubyte(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	return PyInt_FromLong((long) *(unsigned char *)p);
+}
+
+static PyObject *
+nu_short(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	return PyInt_FromLong((long) *(short *)p);
+}
+
+static PyObject *
+nu_ushort(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	return PyInt_FromLong((long) *(unsigned short *)p);
+}
+
+static PyObject *
+nu_int(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	return PyInt_FromLong((long) *(int *)p);
+}
+
+static PyObject *
+nu_uint(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	unsigned int x = *(unsigned int *)p;
+#if INT_MAX == LONG_MAX
+	return make_ulong((long)x);
+#else
+	return PyInt_FromLong((long)x);
+#endif
+}
+
+static PyObject *
+nu_long(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	return PyInt_FromLong(*(long *)p);
+}
+
+static PyObject *
+nu_ulong(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	return make_ulong(*(long *)p);
+}
+
+static PyObject *
+nu_float(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	float x;
+	memcpy((char *)&x, p, sizeof(float));
+	return PyFloat_FromDouble((double)x);
+}
+
+static PyObject *
+nu_double(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	double x;
+	memcpy((char *)&x, p, sizeof(double));
+	return PyFloat_FromDouble(x);
+}
+
+static int
+np_byte(p, v, f)
+	char *p;
+	PyObject *v;
+	const formatdef *f;
+{
+	long x;
+	if (get_long(v, &x) < 0)
+		return -1;
+	*p = x;
+	return 0;
+}
+
+static int
+np_char(p, v, f)
+	char *p;
+	PyObject *v;
+	const formatdef *f;
+{
+	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;
+}
+
+static int
+np_short(p, v, f)
+	char *p;
+	PyObject *v;
+	const formatdef *f;
+{
+	long x;
+	if (get_long(v, &x) < 0)
+		return -1;
+	* (short *)p = x;
+	return 0;
+}
+
+static int
+np_int(p, v, f)
+	char *p;
+	PyObject *v;
+	const formatdef *f;
+{
+	long x;
+	if (get_long(v, &x) < 0)
+		return -1;
+	* (int *)p = x;
+	return 0;
+}
+
+static int
+np_long(p, v, f)
+	char *p;
+	PyObject *v;
+	const formatdef *f;
+{
+	long x;
+	if (get_long(v, &x) < 0)
+		return -1;
+	* (long *)p = x;
+	return 0;
+}
+
+static int
+np_float(p, v, f)
+	char *p;
+	PyObject *v;
+	const formatdef *f;
+{
+	float x = (float)PyFloat_AsDouble(v);
+	if (x == -1 && PyErr_Occurred()) {
+		PyErr_SetString(StructError,
+				"required argument is not a float");
+		return -1;
+	}
+	memcpy(p, (char *)&x, sizeof(float));
+	return 0;
+}
+
+static int
+np_double(p, v, f)
+	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;
+	}
+	memcpy(p, (char *)&x, sizeof(double));
+	return 0;
+}
+
+static formatdef native_table[] = {
+	{'x',	sizeof(char),	0,		NULL},
+	{'b',	sizeof(char),	0,		nu_byte,	np_byte},
+	{'B',	sizeof(char),	0,		nu_ubyte,	np_byte},
+	{'c',	sizeof(char),	0,		nu_char,	np_char},
+	{'s',	sizeof(char),	0,		NULL},
+	{'h',	sizeof(short),	SHORT_ALIGN,	nu_short,	np_short},
+	{'H',	sizeof(short),	SHORT_ALIGN,	nu_ushort,	np_short},
+	{'i',	sizeof(int),	INT_ALIGN,	nu_int,		np_int},
+	{'I',	sizeof(int),	INT_ALIGN,	nu_uint,	np_int},
+	{'l',	sizeof(long),	LONG_ALIGN,	nu_long,	np_long},
+	{'L',	sizeof(long),	LONG_ALIGN,	nu_ulong,	np_long},
+	{'f',	sizeof(float),	FLOAT_ALIGN,	nu_float,	np_float},
+	{'d',	sizeof(double),	DOUBLE_ALIGN,	nu_double,	np_double},
+	{0}
+};
+
+static PyObject *
+bu_int(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	long x = 0;
+	int i = f->size;
+	do {
+		x = (x<<8) | (*p++ & 0xFF);
+	} while (--i > 0);
+	i = 8*(sizeof(long) - f->size);
+	if (i) {
+		x <<= i;
+		x >>= i;
+	}
+	return PyInt_FromLong(x);
+}
+
+static PyObject *
+bu_uint(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	long x = 0;
+	int i = f->size;
+	do {
+		x = (x<<8) | (*p++ & 0xFF);
+	} while (--i > 0);
+	if (f->size == sizeof(long))
+		return make_ulong(x);
+	else
+		return PyLong_FromLong(x);
+}
+
+static int
+bp_int(p, v, f)
+	char *p;
+	PyObject *v;
+	const formatdef *f;
+{
+	long x;
+	int i;
+	if (get_long(v, &x) < 0)
+		return -1;
+	i = f->size;
+	do {
+		p[--i] = x;
+		x >>= 8;
+	} while (i > 0);
+	return 0;
+}
+
+static formatdef bigendian_table[] = {
+	{'x',	1,		0,		NULL},
+	{'b',	1,		0,		bu_int,		bp_int},
+	{'B',	1,		0,		bu_uint,	bp_int},
+	{'c',	1,		0,		nu_char,	np_char},
+	{'s',	1,		0,		NULL},
+	{'h',	2,		0,		bu_int,		bp_int},
+	{'H',	2,		0,		bu_uint,	bp_int},
+	{'i',	4,		0,		bu_int,		bp_int},
+	{'I',	4,		0,		bu_uint,	bp_int},
+	{'l',	4,		0,		bu_int,		bp_int},
+	{'L',	4,		0,		bu_uint,	bp_int},
+	/* No float and double! */
+	{0}
+};
+
+static PyObject *
+lu_int(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	long x = 0;
+	int i = f->size;
+	do {
+		x = (x<<8) | (p[--i] & 0xFF);
+	} while (i > 0);
+	i = 8*(sizeof(long) - f->size);
+	if (i) {
+		x <<= i;
+		x >>= i;
+	}
+	return PyInt_FromLong(x);
+}
+
+static PyObject *
+lu_uint(p, f)
+	const char *p;
+	const formatdef *f;
+{
+	long x = 0;
+	int i = f->size;
+	do {
+		x = (x<<8) | (p[--i] & 0xFF);
+	} while (i > 0);
+	if (f->size == sizeof(long))
+		return make_ulong(x);
+	else
+		return PyLong_FromLong(x);
+}
+
+static int
+lp_int(p, v, f)
+	char *p;
+	PyObject *v;
+	const formatdef *f;
+{
+	long x;
+	int i;
+	if (get_long(v, &x) < 0)
+		return -1;
+	i = f->size;
+	do {
+		*p++ = x;
+		x >>= 8;
+	} while (--i > 0);
+	return 0;
+}
+
+static formatdef lilendian_table[] = {
+	{'x',	1,		0,		NULL},
+	{'b',	1,		0,		lu_int,		lp_int},
+	{'B',	1,		0,		lu_uint,	lp_int},
+	{'c',	1,		0,		nu_char,	np_char},
+	{'s',	1,		0,		NULL},
+	{'h',	2,		0,		lu_int,		lp_int},
+	{'H',	2,		0,		lu_uint,	lp_int},
+	{'i',	4,		0,		lu_int,		lp_int},
+	{'I',	4,		0,		lu_uint,	lp_int},
+	{'l',	4,		0,		lu_int,		lp_int},
+	{'L',	4,		0,		lu_uint,	lp_int},
+	/* No float and double! */
+	{0}
+};
+
+
+static const formatdef *
+whichtable(pfmt)
+	const char **pfmt;
+{
+	const char *fmt = (*pfmt)++; /* May be backed out of later */
+	switch (*fmt) {
+	case '<':
+		return lilendian_table;
+	case '>':
+	case '!': /* Network byte order is big-endian */
+		return bigendian_table;
+	case '=': { /* Host byte order -- different from native in aligment! */
+		int n = 1;
+		char *p = (char *) &n;
+		if (*p == 1)
+			return lilendian_table;
+		else
+			return bigendian_table;
+	}
+	default:
+		--*pfmt; /* Back out of pointer increment */
+		/* Fall through */
+	case '@':
+		return native_table;
+	}
+}
+
+
+/* Get the table entry for a format code */
+
+static const formatdef *
+getentry(c, f)
 	int c;
+	const formatdef *f;
 {
-	int a;
+	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 */
 
-	switch (c) {
-	case 'h': a = SHORT_ALIGN; break;
-	case 'i': a = INT_ALIGN; break;
-	case 'l': a = LONG_ALIGN; break;
-	case 'f': a = FLOAT_ALIGN; break;
-	case 'd': a = DOUBLE_ALIGN; break;
-	default: return size;
+static int
+align(size, c, e)
+	int size;
+	int c;
+	const formatdef *e;
+{
+	if (e->format == c) {
+		if (e->alignment) {
+			size = ((size + e->alignment - 1)
+				/ e->alignment)
+				* e->alignment;
+		}
 	}
-	return (size + a - 1) / a * a;
+	return size;
 }
 
 
 /* calculate the size of a format string */
 
 static int
-calcsize(fmt)
-	char *fmt;
+calcsize(fmt, f)
+	const char *fmt;
+	const formatdef *f;
 {
-	char *s;
+	const formatdef *e;
+	const char *s;
 	char c;
 	int size,  num, itemsize, x;
 
@@ -104,8 +573,9 @@ calcsize(fmt)
 			while ('0' <= (c = *s++) && c <= '9') {
 				x = num*10 + (c - '0');
 				if (x/10 != num) {
-					PyErr_SetString(StructError,
-                                                        "int overflow in fmt");
+					PyErr_SetString(
+						StructError,
+						"overflow in item count");
 					return -1;
 				}
 				num = x;
@@ -116,42 +586,11 @@ calcsize(fmt)
 		else
 			num = 1;
 		
-		size = align(size, c);
-		
-		switch (c) {
-			
-		case 'x': /* pad byte */
-		case 'b': /* byte-sized int */
-		case 'c': /* char */
-			itemsize = 1;
-			break;
-
-		case 'h': /* short ("half-size)" int */
-			itemsize = sizeof(short);
-			break;
-
-		case 'i': /* natural-size int */
-			itemsize = sizeof(int);
-			break;
-
-		case 'l': /* long int */
-			itemsize = sizeof(long);
-			break;
-
-		case 'f': /* float */
-			itemsize = sizeof(float);
-			break;
-
-		case 'd': /* double */
-			itemsize = sizeof(double);
-			break;
-
-		default:
-			PyErr_SetString(StructError, "bad char in fmt");
+		e = getentry(c, f);
+		if (e == NULL)
 			return -1;
-
-		}
-		
+		itemsize = e->size;
+		size = align(size, c, e);
 		x = num * itemsize;
 		size += x;
 		if (x/itemsize != num || size < 0) {
@@ -159,7 +598,6 @@ calcsize(fmt)
                                         "total struct size too long");
 			return -1;
 		}
-			
 	}
 
 	return size;
@@ -174,11 +612,13 @@ struct_calcsize(self, args)
 	PyObject *args;
 {
 	char *fmt;
+	const formatdef *f;
 	int size;
 
-	if (!PyArg_Parse(args, "s", &fmt))
+	if (!PyArg_ParseTuple(args, "s", &fmt))
 		return NULL;
-	size = calcsize(fmt);
+	f = whichtable(&fmt);
+	size = calcsize(fmt, f);
 	if (size < 0)
 		return NULL;
 	return PyInt_FromLong((long)size);
@@ -192,14 +632,13 @@ struct_pack(self, args)
 	PyObject *self; /* Not used */
 	PyObject *args;
 {
+	const formatdef *f, *e;
 	PyObject *format, *result, *v;
 	char *fmt;
 	int size, num;
 	int i, n;
 	char *s, *res, *restart;
 	char c;
-	long ival;
-	double fval;
 
 	if (args == NULL || !PyTuple_Check(args) ||
 	    (n = PyTuple_Size(args)) < 1)
@@ -210,7 +649,8 @@ struct_pack(self, args)
 	format = PyTuple_GetItem(args, 0);
 	if (!PyArg_Parse(format, "s", &fmt))
 		return NULL;
-	size = calcsize(fmt);
+	f = whichtable(&fmt);
+	size = calcsize(fmt, f);
 	if (size < 0)
 		return NULL;
 	result = PyString_FromStringAndSize((char *)NULL, size);
@@ -228,109 +668,60 @@ struct_pack(self, args)
 			       num = num*10 + (c - '0');
 			if (c == '\0')
 				break;
+			if (num == 0 && c != 's')
+				continue;
 		}
 		else
 			num = 1;
 
-		res = restart + align((int)(res-restart), c);
-
-		while (--num >= 0) {
-			switch (c) {
-
-			case 'x': /* pad byte */
-				*res++ = '\0';
-				break;
-
-			case 'l':
-			case 'i':
-			case 'h':
-			case 'b':
-				if (i >= n) {
-					PyErr_SetString(StructError,
-					     "insufficient arguments to pack");
-					goto fail;
-				}
-				v = PyTuple_GetItem(args, i++);
-				if (!PyInt_Check(v)) {
-					PyErr_SetString(StructError,
-					          "bad argument type to pack");
-					goto fail;
-				}
-				ival = PyInt_AsLong(v);
-				switch (c) {
-				case 'b':
-					*res++ = ival;
-					break;
-				case 'h':
-					*(short*)res = ival;
-					res += sizeof(short);
-					break;
-				case 'i':
-					*(int*)res = ival;
-					res += sizeof(int);
-					break;
-				case 'l':
-					*(long*)res = ival;
-					res += sizeof(long);
-					break;
-				}
+		e = getentry(c, f);
+		if (e == NULL)
+			goto fail;
+		res = restart + align((int)(res-restart), c, e);
+		do {
+			if (c == 'x') {
+				/* doesn't consume arguments */
+				memchr(res, '\0', num);
+				res += num;
 				break;
-
-			case 'c':
-				if (i >= n) {
-					PyErr_SetString(StructError,
-					     "insufficient arguments to pack");
-					goto fail;
+			}
+			if (i >= n) {
+				PyErr_SetString(StructError,
+					"insufficient arguments to pack");
+				goto fail;
 				}
-				v = PyTuple_GetItem(args, i++);
-				if (!PyString_Check(v) ||
-				    PyString_Size(v) != 1)
-				{
+			v = PyTuple_GetItem(args, i++);
+			if (v == NULL)
+				goto fail;
+			if (c == 's') {
+				/* num is string size, not repeat count */
+				int n;
+				if (!PyString_Check(v)) {
 					PyErr_SetString(StructError,
-					          "bad argument type to pack");
+					  "argument for 's' must be a string");
 					goto fail;
 				}
-				*res++ = PyString_AsString(v)[0];
+				n = PyString_Size(v);
+				if (n > num)
+					n = num;
+				if (n > 0)
+					memcpy(res, PyString_AsString(v), n);
+				if (n < num)
+					memchr(res+n, '\0', num-n);
+				res += num;
 				break;
-
-			case 'd':
-			case 'f':
-				if (i >= n) {
-					PyErr_SetString(StructError,
-					     "insufficient arguments to pack");
-					goto fail;
-				}
-				v = PyTuple_GetItem(args, i++);
-				if (!PyFloat_Check(v)) {
-					PyErr_SetString(StructError,
-					          "bad argument type to pack");
+			}
+			else {
+				if (e->pack(res, v, e) < 0)
 					goto fail;
-				}
-				fval = PyFloat_AsDouble(v);
-				switch (c) {
-				case 'f':
-					*(float*)res = (float)fval;
-					res += sizeof(float);
-					break;
-				case 'd':
-					memcpy(res, (char*)&fval, sizeof fval);
-					res += sizeof(double);
-					break;
-				}
-				break;
-
-			default:
-				PyErr_SetString(StructError,
-						"bad char in fmt");
-				goto fail;
-
+				res += e->size;
 			}
-		}
+		} while (--num > 0);
 	}
 
 	if (i < n) {
 		PyErr_SetString(StructError,
-				"too many arguments for pack fmt");
+				"too many arguments for pack format");
 		goto fail;
 	}
 
@@ -342,27 +733,6 @@ struct_pack(self, args)
 }
 
 
-/* Helper to convert a list to a tuple */
-
-static PyObject *
-totuple(list)
-	PyObject *list;
-{
-	int len = PyList_Size(list);
-	PyObject *tuple = PyTuple_New(len);
-	if (tuple != NULL) {
-		int i;
-		for (i = 0; i < len; i++) {
-			PyObject *v = PyList_GetItem(list, i);
-			Py_INCREF(v);
-			PyTuple_SetItem(tuple, i, v);
-		}
-	}
-	Py_DECREF(list);
-	return tuple;
-}
-
-
 /* unpack(fmt, string) --> (v1, v2, ...) */
 
 static PyObject *
@@ -370,17 +740,21 @@ struct_unpack(self, args)
 	PyObject *self; /* Not used */
 	PyObject *args;
 {
+	const formatdef *f, *e;
 	char *str, *start, *fmt, *s;
 	char c;
 	int len, size, num, x;
 	PyObject *res, *v;
 
-	if (!PyArg_Parse(args, "(ss#)", &fmt, &start, &len))
+	if (!PyArg_ParseTuple(args, "ss#", &fmt, &start, &len))
+		return NULL;
+	f = whichtable(&fmt);
+	size = calcsize(fmt, f);
+	if (size < 0)
 		return NULL;
-	size = calcsize(fmt);
 	if (size != len) {
 		PyErr_SetString(StructError,
-				"unpack str size does not match fmt");
+				"unpack str size does not match format");
 		return NULL;
 	}
 	res = PyList_New(0);
@@ -395,73 +769,45 @@ struct_unpack(self, args)
 			       num = num*10 + (c - '0');
 			if (c == '\0')
 				break;
+			if (num == 0 && c != 's')
+				break;
 		}
 		else
 			num = 1;
 
-		str = start + align((int)(str-start), c);
-
-		while (--num >= 0) {
-			switch (c) {
-
-			case 'x':
-				str++;
-				continue;
-
-			case 'b':
-				x = *str++;
-				if (x >= 128)
-					x -= 256;
-				v = PyInt_FromLong((long)x);
-				break;
-
-			case 'c':
-				v = PyString_FromStringAndSize(str, 1);
-				str++;
-				break;
-
-			case 'h':
-				v = PyInt_FromLong((long)*(short*)str);
-				str += sizeof(short);
-				break;
-
-			case 'i':
-				v = PyInt_FromLong((long)*(int*)str);
-				str += sizeof(int);
-				break;
-
-			case 'l':
-				v = PyInt_FromLong(*(long*)str);
-				str += sizeof(long);
-				break;
-
-			case 'f':
-				v = PyFloat_FromDouble((double)*(float*)str);
-				str += sizeof(float);
-				break;
+		e = getentry(c, f);
+		if (e == NULL)
+			goto fail;
+		str = start + align((int)(str-start), c, e);
 
-			case 'd':
-			    {
-				double d;
-				memcpy((char *)&d, str, sizeof d);
-				v = PyFloat_FromDouble(d);
-				str += sizeof(double);
+		do {
+			if (c == 'x') {
+				str += num;
 				break;
-			    }
-
-			default:
-				PyErr_SetString(StructError,
-						"bad char in fmt");
-				goto fail;
-
+			}
+			if (c == 's') {
+				/* num is string size, not repeat count */
+				v = PyString_FromStringAndSize(str, num);
+				if (v == NULL)
+					goto fail;
+				str += num;
+				num = 0;
+			}
+			else {
+				v = e->unpack(str, e);
+				if (v == NULL)
+					goto fail;
+				str += e->size;
 			}
 			if (v == NULL || PyList_Append(res, v) < 0)
 				goto fail;
 			Py_DECREF(v);
-		}
+		} while (--num > 0);
 	}
 
-	return totuple(res);
+	v = PyList_AsTuple(res);
+	Py_DECREF(res);
+	return v;
 
  fail:
 	Py_DECREF(res);
@@ -472,9 +818,9 @@ struct_unpack(self, args)
 /* List of functions */
 
 static PyMethodDef struct_methods[] = {
-	{"calcsize",	struct_calcsize},
-	{"pack",	struct_pack,	1/*varargs*/},
-	{"unpack",	struct_unpack},
+	{"calcsize",	struct_calcsize,	METH_VARARGS},
+	{"pack",	struct_pack,		METH_VARARGS},
+	{"unpack",	struct_unpack,		METH_VARARGS},
 	{NULL,		NULL}		/* sentinel */
 };