revert #1493701

2 files changed, 275 insertions, 337 deletions

diff --git a/Modules/Setup.dist b/Modules/Setup.dist
index 1b2502d..49c8425 100644
--- a/Modules/Setup.dist
+++ b/Modules/Setup.dist
@@ -167,7 +167,7 @@ GLHACK=-Dclear=__GLclear
 #array arraymodule.c	# array objects
 #cmath cmathmodule.c # -lm # complex math library functions
 #math mathmodule.c # -lm # math library functions, e.g. sin()
-#_struct _struct.c	# binary structure packing/unpacking
+#struct structmodule.c	# binary structure packing/unpacking
 #time timemodule.c # -lm # time operations and variables
 #operator operator.c	# operator.add() and similar goodies
 #_weakref _weakref.c	# basic weak reference support
diff --git a/Modules/_struct.c b/Modules/structmodule.c
index 838e4e4..4713c0c 100644
--- a/Modules/_struct.c
+++ b/Modules/structmodule.c
@@ -4,51 +4,34 @@
    character strings, and unsigned numbers */
 
 #include "Python.h"
-#include "structseq.h"
-#include "structmember.h"
 #include <ctype.h>
 
-
-/* compatibility macros */
-#if (PY_VERSION_HEX < 0x02050000)
-typedef int Py_ssize_t;
-#endif
-
-
-
-/* The translation function for each format character is table driven */
-
-typedef struct _formatdef {
-	char format;
-	int size;
-	int alignment;
-	PyObject* (*unpack)(const char *,
-			    const struct _formatdef *);
-	int (*pack)(char *, PyObject *,
-		    const struct _formatdef *);
-} formatdef;
-
-typedef struct _formatcode {
-	const struct _formatdef *fmtdef;
-	int offset;
-	int repeat;
-} formatcode;
-
-/* Struct object interface */
-
-typedef struct {
-	PyObject_HEAD
-	int s_size;
-	int s_len;
-	formatcode *s_codes;
-	PyObject *s_format;
-	PyObject *weakreflist; /* List of weak references */
-} PyStructObject;
-
-PyAPI_DATA(PyTypeObject) PyStruct_Type;
-
-#define PyStruct_Check(op) PyObject_TypeCheck(op, &PyStruct_Type)
-#define PyStruct_CheckExact(op) ((op)->ob_type == &PyStruct_Type)
+PyDoc_STRVAR(struct__doc__,
+"Functions to convert between Python values and C structs.\n\
+Python strings are used to hold the data representing the C struct\n\
+and also as format strings to describe the layout of data in the C struct.\n\
+\n\
+The optional first format char indicates byte order, size and alignment:\n\
+ @: native order, size & alignment (default)\n\
+ =: native order, std. size & alignment\n\
+ <: little-endian, std. size & alignment\n\
+ >: big-endian, std. size & alignment\n\
+ !: same as >\n\
+\n\
+The remaining chars indicate types of args and must match exactly;\n\
+these can be preceded by a decimal repeat count:\n\
+ x: pad byte (no data); c:char; b:signed byte; B:unsigned byte;\n\
+ h:short; H:unsigned short; i:int; I:unsigned int;\n\
+ l:long; L:unsigned long; f:float; d:double.\n\
+Special cases (preceding decimal count indicates length):\n\
+ s:string (array of char); p: pascal string (with count byte).\n\
+Special case (only available in native format):\n\
+ P:an integer type that is wide enough to hold a pointer.\n\
+Special case (not in native mode unless 'long long' in platform C):\n\
+ q:long long; Q:unsigned long long\n\
+Whitespace between formats is ignored.\n\
+\n\
+The variable struct.error is an exception raised on errors.");
 
 
 /* Exception */
@@ -218,6 +201,18 @@ unpack_double(const char *p,  /* start of 8-byte string */
 }
 
 
+/* The translation function for each format character is table driven */
+
+typedef struct _formatdef {
+	char format;
+	int size;
+	int alignment;
+	PyObject* (*unpack)(const char *,
+			    const struct _formatdef *);
+	int (*pack)(char *, PyObject *,
+		    const struct _formatdef *);
+} formatdef;
+
 /* A large number of small routines follow, with names of the form
 
 	[bln][up]_TYPE
@@ -954,25 +949,15 @@ align(int size, int c, const formatdef *e)
 /* calculate the size of a format string */
 
 static int
-prepare_s(PyStructObject *self)
+calcsize(const char *fmt, const formatdef *f)
 {
-	const formatdef *f;
 	const formatdef *e;
-	formatcode *codes;
-	
 	const char *s;
-	const char *fmt;
 	char c;
-	int size, len, numcodes, num, itemsize, x;
+	int size,  num, itemsize, x;
 
-	fmt = PyString_AS_STRING(self->s_format);
-
-	f = whichtable((char **)&fmt);
-	
 	s = fmt;
 	size = 0;
-	len = 0;
-	numcodes = 0;
 	while ((c = *s++) != '\0') {
 		if (isspace(Py_CHARMASK(c)))
 			continue;
@@ -997,15 +982,6 @@ prepare_s(PyStructObject *self)
 		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;
-		}
-		if (c != 'x') numcodes++;
-
 		itemsize = e->size;
 		size = align(size, c, e);
 		x = num * itemsize;
@@ -1017,328 +993,292 @@ prepare_s(PyStructObject *self)
 		}
 	}
 
-	self->s_size = size;
-	self->s_len = len;
-	codes = PyMem_MALLOC((numcodes + 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 != 'x') {
-			codes->offset = size;
-			codes->repeat = num;
-			codes->fmtdef = e;
-			codes++;
-		}
-		size += num * e->size;
-	}
-	codes->fmtdef = NULL;
-	codes->offset = -1;
-	codes->repeat = -1;
-	
-	return 0;
+	return size;
 }
 
-static PyObject *
-s_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
-{
-	PyObject *self;
-	static PyObject *not_yet_string;
-
-	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;
-}
+PyDoc_STRVAR(calcsize__doc__,
+"calcsize(fmt) -> int\n\
+Return size of C struct described by format string fmt.\n\
+See struct.__doc__ for more on format strings.");
 
-static int
-s_init(PyObject *self, PyObject *args, PyObject *kwds)
+static PyObject *
+struct_calcsize(PyObject *self, PyObject *args)
 {
-	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;
+	char *fmt;
+	const formatdef *f;
+	int size;
 
-	Py_INCREF(o_format);
-	Py_XDECREF(soself->s_format);
-	soself->s_format = o_format;
-	
-	ret = prepare_s(soself);
-	return ret;
+	if (!PyArg_ParseTuple(args, "s:calcsize", &fmt))
+		return NULL;
+	f = whichtable(&fmt);
+	size = calcsize(fmt, f);
+	if (size < 0)
+		return NULL;
+	return PyInt_FromLong((long)size);
 }
 
-static void
-s_dealloc(PyStructObject *s)
-{
-	int sts = 0;
-	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);
-}
 
-PyDoc_STRVAR(s_unpack__doc__,
-"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.");
+PyDoc_STRVAR(pack__doc__,
+"pack(fmt, v1, v2, ...) -> string\n\
+Return string containing values v1, v2, ... packed according to fmt.\n\
+See struct.__doc__ for more on format strings.");
 
 static PyObject *
-s_unpack(PyObject *self, PyObject *inputstr)
-{
-	PyStructObject *soself;
-	PyObject *result;
-	char *restart;
-	formatcode *code;
-	Py_ssize_t i;
-	
-	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 %d", soself->s_size);
+struct_pack(PyObject *self, PyObject *args)
+{
+	const formatdef *f, *e;
+	PyObject *format, *result, *v;
+	char *fmt;
+	int size, num;
+	Py_ssize_t i, n;
+	char *s, *res, *restart, *nres;
+	char c;
+
+	if (args == NULL || !PyTuple_Check(args) ||
+	    (n = PyTuple_Size(args)) < 1)
+	{
+		PyErr_SetString(PyExc_TypeError,
+			"struct.pack requires at least one argument");
 		return NULL;
 	}
-	result = PyTuple_New(soself->s_len);
+	format = PyTuple_GetItem(args, 0);
+	fmt = PyString_AsString(format);
+	if (!fmt)
+		return NULL;
+	f = whichtable(&fmt);
+	size = calcsize(fmt, f);
+	if (size < 0)
+		return NULL;
+	result = PyString_FromStringAndSize((char *)NULL, size);
 	if (result == NULL)
 		return NULL;
-	
-
-	restart = PyString_AS_STRING(inputstr);
-	i = 0;
-	for (code = soself->s_codes; code->fmtdef != NULL; code++) {
-		Py_ssize_t n;
-		PyObject *v;
-		const formatdef *e = code->fmtdef;
-		const char *res = restart + code->offset;
-		if (e->format == 's') {
-			v = PyString_FromStringAndSize(res, code->repeat);
-			if (v == NULL)
+
+	s = fmt;
+	i = 1;
+	res = restart = PyString_AsString(result);
+
+	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);
+		if (e == NULL)
+			goto fail;
+		nres = restart + align((int)(res-restart), c, e);
+		/* Fill padd bytes with zeros */
+		while (res < nres)
+			*res++ = '\0';
+		if (num == 0 && c != 's')
+			continue;
+		do {
+			if (c == 'x') {
+				/* doesn't consume arguments */
+				memset(res, '\0', num);
+				res += num;
+				break;
+			}
+			if (i >= n) {
+				PyErr_SetString(StructError,
+					"insufficient arguments to pack");
 				goto fail;
-			PyTuple_SET_ITEM(result, i++, v);
-		} else if (e->format == 'p') {
-			n = *(unsigned char*)res;
-			if (n >= code->repeat)
-				n = code->repeat - 1;
-			v = PyString_FromStringAndSize(res + 1, n);
+				}
+			v = PyTuple_GetItem(args, i++);
 			if (v == NULL)
 				goto fail;
-			PyTuple_SET_ITEM(result, i++, v);
-		} else {
-			for (n = 0; n < code->repeat; n++) {
-				v = e->unpack(res, e);
-				if (v == NULL)
+			if (c == 's') {
+				/* num is string size, not repeat count */
+				Py_ssize_t n;
+				if (!PyString_Check(v)) {
+					PyErr_SetString(StructError,
+					  "argument for 's' must be a string");
+					goto fail;
+				}
+				n = PyString_Size(v);
+				if (n > num)
+					n = num;
+				if (n > 0)
+					memcpy(res, PyString_AsString(v), n);
+				if (n < num)
+					memset(res+n, '\0', num-n);
+				res += num;
+				break;
+			}
+			else if (c == 'p') {
+				/* num is string size + 1,
+				   to fit in the count byte */
+				Py_ssize_t n;
+				num--; /* now num is max string size */
+				if (!PyString_Check(v)) {
+					PyErr_SetString(StructError,
+					  "argument for 'p' must be a string");
+					goto fail;
+				}
+				n = PyString_Size(v);
+				if (n > num)
+					n = num;
+				if (n > 0)
+					memcpy(res+1, PyString_AsString(v), n);
+				if (n < num)
+					/* no real need, just to be nice */
+					memset(res+1+n, '\0', num-n);
+				if (n > 255)
+					n = 255;
+				/* store the length byte */
+				*res++ = Py_SAFE_DOWNCAST(n, Py_ssize_t, unsigned char);
+				res += num;
+				break;
+			}
+			else {
+				if (e->pack(res, v, e) < 0)
 					goto fail;
-				PyTuple_SET_ITEM(result, i++, v);
 				res += e->size;
 			}
-		}
+		} while (--num > 0);
+	}
+
+	if (i < n) {
+		PyErr_SetString(StructError,
+				"too many arguments for pack format");
+		goto fail;
 	}
 
 	return result;
-fail:
+
+ fail:
 	Py_DECREF(result);
 	return NULL;
-};
+}
 
 
-PyDoc_STRVAR(s_pack__doc__,
-"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.");
+PyDoc_STRVAR(unpack__doc__,
+"unpack(fmt, string) -> (v1, v2, ...)\n\
+Unpack the string, containing packed C structure data, according\n\
+to fmt.  Requires len(string)==calcsize(fmt).\n\
+See struct.__doc__ for more on format strings.");
 
 static PyObject *
-s_pack(PyObject *self, PyObject *args)
-{
-	PyStructObject *soself;
-	PyObject *result;
-	char *restart;
-	formatcode *code;
-	Py_ssize_t i;
-	
-	soself = (PyStructObject *)self;
-	assert(PyStruct_Check(self));
-	assert(soself->s_codes != NULL);
-	if (args == NULL || !PyTuple_Check(args) ||
-	    PyTuple_GET_SIZE(args) != soself->s_len)
-	{
-		PyErr_Format(StructError,
-			"pack requires exactly %d arguments", soself->s_len);
+struct_unpack(PyObject *self, PyObject *args)
+{
+	const formatdef *f, *e;
+	char *str, *start, *fmt, *s;
+	char c;
+	int len, size, num;
+	PyObject *res, *v;
+
+	if (!PyArg_ParseTuple(args, "ss#:unpack", &fmt, &start, &len))
+		return NULL;
+	f = whichtable(&fmt);
+	size = calcsize(fmt, f);
+	if (size < 0)
+		return NULL;
+	if (size != len) {
+		PyErr_SetString(StructError,
+				"unpack str size does not match format");
 		return NULL;
 	}
-	
-	result = PyString_FromStringAndSize((char *)NULL, soself->s_size);
-	if (result == NULL)
+	res = PyList_New(0);
+	if (res == NULL)
 		return NULL;
-	
-	restart = PyString_AS_STRING(result);
-	memset(restart, '\0', soself->s_size);
-	i = 0;
-	for (code = soself->s_codes; code->fmtdef != NULL; code++) {
-		Py_ssize_t n;
-		PyObject *v;
-		const formatdef *e = code->fmtdef;
-		char *res = restart + code->offset;
-		if (e->format == 's') {
-			v = PyTuple_GET_ITEM(args, i++);
-			if (!PyString_Check(v)) {
-				PyErr_SetString(StructError,
-						"argument for 's' must be a string");
-				goto fail;
+	str = start;
+	s = fmt;
+	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);
+		if (e == NULL)
+			goto fail;
+		str = start + align((int)(str-start), c, e);
+		if (num == 0 && c != 's')
+			continue;
+
+		do {
+			if (c == 'x') {
+				str += num;
+				break;
 			}
-			n = PyString_GET_SIZE(v);
-			if (n > code->repeat)
-				n = code->repeat;
-			if (n > 0)
-				memcpy(res, PyString_AS_STRING(v), n);
-		} else if (e->format == 'p') {
-			v = PyTuple_GET_ITEM(args, i++);
-			if (!PyString_Check(v)) {
-				PyErr_SetString(StructError,
-						"argument for 'p' must be a string");
-				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;
 			}
-			n = PyString_GET_SIZE(v);
-			if (n > (code->repeat - 1))
-				n = code->repeat - 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 {
-			for (n = 0; n < code->repeat; n++) {
-				v = PyTuple_GET_ITEM(args, i++);
-				if (e->pack(res, v, e) < 0)
+			else if (c == 'p') {
+				/* num is string buffer size,
+				   not repeat count */
+				int n = *(unsigned char*)str;
+				/* first byte (unsigned) is string size */
+				if (n >= num)
+					n = num-1;
+				v = PyString_FromStringAndSize(str+1, n);
+				if (v == NULL)
 					goto fail;
-				res += e->size;
+				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 result;
 
-fail:
-	Py_DECREF(result);
+	v = PyList_AsTuple(res);
+	Py_DECREF(res);
+	return v;
+
+ fail:
+	Py_DECREF(res);
 	return NULL;
-	
 }
 
 
 /* List of functions */
 
-static struct PyMethodDef s_methods[] = {
-	{"pack",	s_pack,		METH_VARARGS, s_pack__doc__},
-	{"unpack",	s_unpack,	METH_O, s_unpack__doc__},
-	{NULL,	 NULL}		/* sentinel */
+static PyMethodDef struct_methods[] = {
+	{"calcsize",	struct_calcsize,	METH_VARARGS, calcsize__doc__},
+	{"pack",	struct_pack,		METH_VARARGS, pack__doc__},
+	{"unpack",	struct_unpack,		METH_VARARGS, unpack__doc__},
+	{NULL,		NULL}		/* sentinel */
 };
 
-PyDoc_STRVAR(s__doc__, "Compiled struct object");
-
-#define OFF(x) offsetof(PyStructObject, x)
-
-static PyMemberDef s_memberlist[] = {
-	{"format",	T_OBJECT,	OFF(s_format),	RO,
-	 "struct format string"},
-	{"size",	T_INT,		OFF(s_size),	RO,
-	 "struct size in bytes"},
-	{"_len",	T_INT,		OFF(s_len),	RO,
-	 "number of items expected in tuple"},
-	{NULL}	/* Sentinel */
-};
-
-
-static
-PyTypeObject PyStructType = {
-	PyObject_HEAD_INIT(&PyType_Type)
-	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 | Py_TPFLAGS_HAVE_WEAKREFS, /* 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 */
-	s_memberlist,				/* tp_members */
-	0,					/* tp_getset */
-	0,					/* tp_base */
-	0,					/* tp_dict */
-	0,					/* tp_descr_get */
-	0,					/* tp_descr_set */
-	0,					/* tp_dictoffset */
-	s_init,					/* tp_init */
-	PyType_GenericAlloc,			/* tp_alloc */
-	s_new,					/* tp_new */
-	PyObject_Del,				/* tp_free */
-};
 
 /* Module initialization */
 
 PyMODINIT_FUNC
-init_struct(void)
+initstruct(void)
 {
-	PyObject *m = Py_InitModule("_struct", NULL);
+	PyObject *m;
+
+	/* Create the module and add the functions */
+	m = Py_InitModule4("struct", struct_methods, struct__doc__,
+			   (PyObject*)NULL, PYTHON_API_VERSION);
 	if (m == NULL)
 		return;
 
@@ -1350,6 +1290,4 @@ init_struct(void)
 	}
 	Py_INCREF(StructError);
 	PyModule_AddObject(m, "error", StructError);
-	Py_INCREF((PyObject*)&PyStructType);
-	PyModule_AddObject(m, "Struct", (PyObject*)&PyStructType);
 }