view contrib/python-zstandard/c-ext/bufferutil.c @ 36747:4c71a26a4009

sslutil: some more forcebytes() on some exception messages

At this point, test-https.t no longer dumps tracebacks
everywhere. Instead, we get some results that look like we're not
adequately finding things in hg's configuration, which should be
manageable (if somewhat annoying to find and fix.)

Differential Revision: https://phab.mercurial-scm.org/D2690

/**
* Copyright (c) 2017-present, Gregory Szorc
* All rights reserved.
*
* This software may be modified and distributed under the terms
* of the BSD license. See the LICENSE file for details.
*/

#include "python-zstandard.h"

extern PyObject* ZstdError;

PyDoc_STRVAR(BufferWithSegments__doc__,
"BufferWithSegments - A memory buffer holding known sub-segments.\n"
"\n"
"This type represents a contiguous chunk of memory containing N discrete\n"
"items within sub-segments of that memory.\n"
"\n"
"Segments within the buffer are stored as an array of\n"
"``(offset, length)`` pairs, where each element is an unsigned 64-bit\n"
"integer using the host/native bit order representation.\n"
"\n"
"The type exists to facilitate operations against N>1 items without the\n"
"overhead of Python object creation and management.\n"
);

static void BufferWithSegments_dealloc(ZstdBufferWithSegments* self) {
	/* Backing memory is either canonically owned by a Py_buffer or by us. */
	if (self->parent.buf) {
		PyBuffer_Release(&self->parent);
	}
	else if (self->useFree) {
		free(self->data);
	}
	else {
		PyMem_Free(self->data);
	}

	self->data = NULL;

	if (self->useFree) {
		free(self->segments);
	}
	else {
		PyMem_Free(self->segments);
	}

	self->segments = NULL;

	PyObject_Del(self);
}

static int BufferWithSegments_init(ZstdBufferWithSegments* self, PyObject* args, PyObject* kwargs) {
	static char* kwlist[] = {
		"data",
		"segments",
		NULL
	};

	Py_buffer segments;
	Py_ssize_t segmentCount;
	Py_ssize_t i;

	memset(&self->parent, 0, sizeof(self->parent));

#if PY_MAJOR_VERSION >= 3
	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "y*y*:BufferWithSegments",
#else
	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s*s*:BufferWithSegments",
#endif
		kwlist, &self->parent, &segments)) {
		return -1;
	}

	if (!PyBuffer_IsContiguous(&self->parent, 'C') || self->parent.ndim > 1) {
		PyErr_SetString(PyExc_ValueError, "data buffer should be contiguous and have a single dimension");
		goto except;
	}

	if (!PyBuffer_IsContiguous(&segments, 'C') || segments.ndim > 1) {
		PyErr_SetString(PyExc_ValueError, "segments buffer should be contiguous and have a single dimension");
		goto except;
	}

	if (segments.len % sizeof(BufferSegment)) {
		PyErr_Format(PyExc_ValueError, "segments array size is not a multiple of %lu",
			sizeof(BufferSegment));
		goto except;
	}

	segmentCount = segments.len / sizeof(BufferSegment);

	/* Validate segments data, as blindly trusting it could lead to arbitrary
	memory access. */
	for (i = 0; i < segmentCount; i++) {
		BufferSegment* segment = &((BufferSegment*)(segments.buf))[i];

		if (segment->offset + segment->length > (unsigned long long)self->parent.len) {
			PyErr_SetString(PyExc_ValueError, "offset within segments array references memory outside buffer");
			goto except;
			return -1;
		}
	}

	/* Make a copy of the segments data. It is cheap to do so and is a guard
	   against caller changing offsets, which has security implications. */
	self->segments = PyMem_Malloc(segments.len);
	if (!self->segments) {
		PyErr_NoMemory();
		goto except;
	}

	memcpy(self->segments, segments.buf, segments.len);
	PyBuffer_Release(&segments);

	self->data = self->parent.buf;
	self->dataSize = self->parent.len;
	self->segmentCount = segmentCount;

	return 0;

except:
	PyBuffer_Release(&self->parent);
	PyBuffer_Release(&segments);
	return -1;
};

/**
 * Construct a BufferWithSegments from existing memory and offsets.
 *
 * Ownership of the backing memory and BufferSegments will be transferred to
 * the created object and freed when the BufferWithSegments is destroyed.
 */
ZstdBufferWithSegments* BufferWithSegments_FromMemory(void* data, unsigned long long dataSize,
	BufferSegment* segments, Py_ssize_t segmentsSize) {
	ZstdBufferWithSegments* result = NULL;
	Py_ssize_t i;

	if (NULL == data) {
		PyErr_SetString(PyExc_ValueError, "data is NULL");
		return NULL;
	}

	if (NULL == segments) {
		PyErr_SetString(PyExc_ValueError, "segments is NULL");
		return NULL;
	}

	for (i = 0; i < segmentsSize; i++) {
		BufferSegment* segment = &segments[i];

		if (segment->offset + segment->length > dataSize) {
			PyErr_SetString(PyExc_ValueError, "offset in segments overflows buffer size");
			return NULL;
		}
	}

	result = PyObject_New(ZstdBufferWithSegments, &ZstdBufferWithSegmentsType);
	if (NULL == result) {
		return NULL;
	}

	result->useFree = 0;

	memset(&result->parent, 0, sizeof(result->parent));
	result->data = data;
	result->dataSize = dataSize;
	result->segments = segments;
	result->segmentCount = segmentsSize;

	return result;
}

static Py_ssize_t BufferWithSegments_length(ZstdBufferWithSegments* self) {
	return self->segmentCount;
}

static ZstdBufferSegment* BufferWithSegments_item(ZstdBufferWithSegments* self, Py_ssize_t i) {
	ZstdBufferSegment* result = NULL;

	if (i < 0) {
		PyErr_SetString(PyExc_IndexError, "offset must be non-negative");
		return NULL;
	}

	if (i >= self->segmentCount) {
		PyErr_Format(PyExc_IndexError, "offset must be less than %zd", self->segmentCount);
		return NULL;
	}

	result = (ZstdBufferSegment*)PyObject_CallObject((PyObject*)&ZstdBufferSegmentType, NULL);
	if (NULL == result) {
		return NULL;
	}

	result->parent = (PyObject*)self;
	Py_INCREF(self);

	result->data = (char*)self->data + self->segments[i].offset;
	result->dataSize = self->segments[i].length;
	result->offset = self->segments[i].offset;

	return result;
}

#if PY_MAJOR_VERSION >= 3
static int BufferWithSegments_getbuffer(ZstdBufferWithSegments* self, Py_buffer* view, int flags) {
	return PyBuffer_FillInfo(view, (PyObject*)self, self->data, self->dataSize, 1, flags);
}
#else
static Py_ssize_t BufferWithSegments_getreadbuffer(ZstdBufferWithSegments* self, Py_ssize_t segment, void **ptrptr) {
	if (segment != 0) {
		PyErr_SetString(PyExc_ValueError, "segment number must be 0");
		return -1;
	}

	*ptrptr = self->data;
	return self->dataSize;
}

static Py_ssize_t BufferWithSegments_getsegcount(ZstdBufferWithSegments* self, Py_ssize_t* len) {
	if (len) {
		*len = 1;
	}

	return 1;
}
#endif

PyDoc_STRVAR(BufferWithSegments_tobytes__doc__,
"Obtain a bytes instance for this buffer.\n"
);

static PyObject* BufferWithSegments_tobytes(ZstdBufferWithSegments* self) {
	return PyBytes_FromStringAndSize(self->data, self->dataSize);
}

PyDoc_STRVAR(BufferWithSegments_segments__doc__,
"Obtain a BufferSegments describing segments in this sintance.\n"
);

static ZstdBufferSegments* BufferWithSegments_segments(ZstdBufferWithSegments* self) {
	ZstdBufferSegments* result = (ZstdBufferSegments*)PyObject_CallObject((PyObject*)&ZstdBufferSegmentsType, NULL);
	if (NULL == result) {
		return NULL;
	}

	result->parent = (PyObject*)self;
	Py_INCREF(self);
	result->segments = self->segments;
	result->segmentCount = self->segmentCount;

	return result;
}

static PySequenceMethods BufferWithSegments_sq = {
	(lenfunc)BufferWithSegments_length, /* sq_length */
	0, /* sq_concat */
	0, /* sq_repeat */
	(ssizeargfunc)BufferWithSegments_item, /* sq_item */
	0, /* sq_ass_item */
	0, /* sq_contains */
	0, /* sq_inplace_concat */
	0 /* sq_inplace_repeat */
};

static PyBufferProcs BufferWithSegments_as_buffer = {
#if PY_MAJOR_VERSION >= 3
	(getbufferproc)BufferWithSegments_getbuffer, /* bf_getbuffer */
	0 /* bf_releasebuffer */
#else
	(readbufferproc)BufferWithSegments_getreadbuffer, /* bf_getreadbuffer */
	0, /* bf_getwritebuffer */
	(segcountproc)BufferWithSegments_getsegcount, /* bf_getsegcount */
	0 /* bf_getcharbuffer */
#endif
};

static PyMethodDef BufferWithSegments_methods[] = {
	{ "segments", (PyCFunction)BufferWithSegments_segments,
	  METH_NOARGS, BufferWithSegments_segments__doc__ },
	{ "tobytes", (PyCFunction)BufferWithSegments_tobytes,
	  METH_NOARGS, BufferWithSegments_tobytes__doc__ },
	{ NULL, NULL }
};

static PyMemberDef BufferWithSegments_members[] = {
	{ "size", T_ULONGLONG, offsetof(ZstdBufferWithSegments, dataSize),
	  READONLY, "total size of the buffer in bytes" },
	{ NULL }
};

PyTypeObject ZstdBufferWithSegmentsType = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"zstd.BufferWithSegments", /* tp_name */
	sizeof(ZstdBufferWithSegments),/* tp_basicsize */
	0,                         /* tp_itemsize */
	(destructor)BufferWithSegments_dealloc, /* tp_dealloc */
	0,                         /* tp_print */
	0,                         /* tp_getattr */
	0,                         /* tp_setattr */
	0,                         /* tp_compare */
	0,                         /* tp_repr */
	0,                         /* tp_as_number */
	&BufferWithSegments_sq,    /* tp_as_sequence */
	0,                         /* tp_as_mapping */
	0,                         /* tp_hash  */
	0,                         /* tp_call */
	0,                         /* tp_str */
	0,                         /* tp_getattro */
	0,                         /* tp_setattro */
	&BufferWithSegments_as_buffer, /* tp_as_buffer */
	Py_TPFLAGS_DEFAULT,        /* tp_flags */
	BufferWithSegments__doc__, /* tp_doc */
	0,                         /* tp_traverse */
	0,                         /* tp_clear */
	0,                         /* tp_richcompare */
	0,                         /* tp_weaklistoffset */
	0,                         /* tp_iter */
	0,                         /* tp_iternext */
	BufferWithSegments_methods, /* tp_methods */
	BufferWithSegments_members, /* tp_members */
	0,                         /* tp_getset */
	0,                         /* tp_base */
	0,                         /* tp_dict */
	0,                         /* tp_descr_get */
	0,                         /* tp_descr_set */
	0,                         /* tp_dictoffset */
	(initproc)BufferWithSegments_init, /* tp_init */
	0,                         /* tp_alloc */
	PyType_GenericNew,         /* tp_new */
};

PyDoc_STRVAR(BufferSegments__doc__,
"BufferSegments - Represents segments/offsets within a BufferWithSegments\n"
);

static void BufferSegments_dealloc(ZstdBufferSegments* self) {
	Py_CLEAR(self->parent);
	PyObject_Del(self);
}

#if PY_MAJOR_VERSION >= 3
static int BufferSegments_getbuffer(ZstdBufferSegments* self, Py_buffer* view, int flags) {
	return PyBuffer_FillInfo(view, (PyObject*)self,
		(void*)self->segments, self->segmentCount * sizeof(BufferSegment),
		1, flags);
}
#else
static Py_ssize_t BufferSegments_getreadbuffer(ZstdBufferSegments* self, Py_ssize_t segment, void **ptrptr) {
	if (segment != 0) {
		PyErr_SetString(PyExc_ValueError, "segment number must be 0");
		return -1;
	}

	*ptrptr = (void*)self->segments;
	return self->segmentCount * sizeof(BufferSegment);
}

static Py_ssize_t BufferSegments_getsegcount(ZstdBufferSegments* self, Py_ssize_t* len) {
	if (len) {
		*len = 1;
	}

	return 1;
}
#endif

static PyBufferProcs BufferSegments_as_buffer = {
#if PY_MAJOR_VERSION >= 3
	(getbufferproc)BufferSegments_getbuffer,
	0
#else
	(readbufferproc)BufferSegments_getreadbuffer,
	0,
	(segcountproc)BufferSegments_getsegcount,
	0
#endif
};

PyTypeObject ZstdBufferSegmentsType = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"zstd.BufferSegments", /* tp_name */
	sizeof(ZstdBufferSegments),/* tp_basicsize */
	0,                         /* tp_itemsize */
	(destructor)BufferSegments_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 */
	0,                         /* tp_getattro */
	0,                         /* tp_setattro */
	&BufferSegments_as_buffer, /* tp_as_buffer */
	Py_TPFLAGS_DEFAULT,        /* tp_flags */
	BufferSegments__doc__,     /* tp_doc */
	0,                         /* tp_traverse */
	0,                         /* tp_clear */
	0,                         /* tp_richcompare */
	0,                         /* tp_weaklistoffset */
	0,                         /* tp_iter */
	0,                         /* tp_iternext */
	0,                         /* tp_methods */
	0,                         /* tp_members */
	0,                         /* tp_getset */
	0,                         /* tp_base */
	0,                         /* tp_dict */
	0,                         /* tp_descr_get */
	0,                         /* tp_descr_set */
	0,                         /* tp_dictoffset */
	0,                         /* tp_init */
	0,                         /* tp_alloc */
	PyType_GenericNew,         /* tp_new */
};

PyDoc_STRVAR(BufferSegment__doc__,
	"BufferSegment - Represents a segment within a BufferWithSegments\n"
);

static void BufferSegment_dealloc(ZstdBufferSegment* self) {
	Py_CLEAR(self->parent);
	PyObject_Del(self);
}

static Py_ssize_t BufferSegment_length(ZstdBufferSegment* self) {
	return self->dataSize;
}

#if PY_MAJOR_VERSION >= 3
static int BufferSegment_getbuffer(ZstdBufferSegment* self, Py_buffer* view, int flags) {
	return PyBuffer_FillInfo(view, (PyObject*)self,
		self->data, self->dataSize, 1, flags);
}
#else
static Py_ssize_t BufferSegment_getreadbuffer(ZstdBufferSegment* self, Py_ssize_t segment, void **ptrptr) {
	if (segment != 0) {
		PyErr_SetString(PyExc_ValueError, "segment number must be 0");
		return -1;
	}

	*ptrptr = self->data;
	return self->dataSize;
}

static Py_ssize_t BufferSegment_getsegcount(ZstdBufferSegment* self, Py_ssize_t* len) {
	if (len) {
		*len = 1;
	}

	return 1;
}
#endif

PyDoc_STRVAR(BufferSegment_tobytes__doc__,
"Obtain a bytes instance for this segment.\n"
);

static PyObject* BufferSegment_tobytes(ZstdBufferSegment* self) {
	return PyBytes_FromStringAndSize(self->data, self->dataSize);
}

static PySequenceMethods BufferSegment_sq = {
	(lenfunc)BufferSegment_length, /* sq_length */
	0, /* sq_concat */
	0, /* sq_repeat */
	0, /* sq_item */
	0, /* sq_ass_item */
	0, /* sq_contains */
	0, /* sq_inplace_concat */
	0 /* sq_inplace_repeat */
};

static PyBufferProcs BufferSegment_as_buffer = {
#if PY_MAJOR_VERSION >= 3
	(getbufferproc)BufferSegment_getbuffer,
	0
#else
	(readbufferproc)BufferSegment_getreadbuffer,
	0,
	(segcountproc)BufferSegment_getsegcount,
	0
#endif
};

static PyMethodDef BufferSegment_methods[] = {
	{ "tobytes", (PyCFunction)BufferSegment_tobytes,
	  METH_NOARGS, BufferSegment_tobytes__doc__ },
	{ NULL, NULL }
};

static PyMemberDef BufferSegment_members[] = {
	{ "offset", T_ULONGLONG, offsetof(ZstdBufferSegment, offset), READONLY,
	  "offset of segment within parent buffer" },
	  { NULL }
};

PyTypeObject ZstdBufferSegmentType = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"zstd.BufferSegment", /* tp_name */
	sizeof(ZstdBufferSegment),/* tp_basicsize */
	0,                         /* tp_itemsize */
	(destructor)BufferSegment_dealloc, /* tp_dealloc */
	0,                         /* tp_print */
	0,                         /* tp_getattr */
	0,                         /* tp_setattr */
	0,                         /* tp_compare */
	0,                         /* tp_repr */
	0,                         /* tp_as_number */
	&BufferSegment_sq,         /* tp_as_sequence */
	0,                         /* tp_as_mapping */
	0,                         /* tp_hash  */
	0,                         /* tp_call */
	0,                         /* tp_str */
	0,                         /* tp_getattro */
	0,                         /* tp_setattro */
	&BufferSegment_as_buffer,  /* tp_as_buffer */
	Py_TPFLAGS_DEFAULT,        /* tp_flags */
	BufferSegment__doc__,      /* tp_doc */
	0,                         /* tp_traverse */
	0,                         /* tp_clear */
	0,                         /* tp_richcompare */
	0,                         /* tp_weaklistoffset */
	0,                         /* tp_iter */
	0,                         /* tp_iternext */
	BufferSegment_methods,     /* tp_methods */
	BufferSegment_members,     /* tp_members */
	0,                         /* tp_getset */
	0,                         /* tp_base */
	0,                         /* tp_dict */
	0,                         /* tp_descr_get */
	0,                         /* tp_descr_set */
	0,                         /* tp_dictoffset */
	0,                         /* tp_init */
	0,                         /* tp_alloc */
	PyType_GenericNew,         /* tp_new */
};

PyDoc_STRVAR(BufferWithSegmentsCollection__doc__,
"Represents a collection of BufferWithSegments.\n"
);

static void BufferWithSegmentsCollection_dealloc(ZstdBufferWithSegmentsCollection* self) {
	Py_ssize_t i;

	if (self->firstElements) {
		PyMem_Free(self->firstElements);
		self->firstElements = NULL;
	}

	if (self->buffers) {
		for (i = 0; i < self->bufferCount; i++) {
			Py_CLEAR(self->buffers[i]);
		}

		PyMem_Free(self->buffers);
		self->buffers = NULL;
	}

	PyObject_Del(self);
}

static int BufferWithSegmentsCollection_init(ZstdBufferWithSegmentsCollection* self, PyObject* args) {
	Py_ssize_t size;
	Py_ssize_t i;
	Py_ssize_t offset = 0;

	size = PyTuple_Size(args);
	if (-1 == size) {
		return -1;
	}

	if (0 == size) {
		PyErr_SetString(PyExc_ValueError, "must pass at least 1 argument");
		return -1;
	}

	for (i = 0; i < size; i++) {
		PyObject* item = PyTuple_GET_ITEM(args, i);
		if (!PyObject_TypeCheck(item, &ZstdBufferWithSegmentsType)) {
			PyErr_SetString(PyExc_TypeError, "arguments must be BufferWithSegments instances");
			return -1;
		}

		if (0 == ((ZstdBufferWithSegments*)item)->segmentCount ||
			0 == ((ZstdBufferWithSegments*)item)->dataSize) {
			PyErr_SetString(PyExc_ValueError, "ZstdBufferWithSegments cannot be empty");
			return -1;
		}
	}

	self->buffers = PyMem_Malloc(size * sizeof(ZstdBufferWithSegments*));
	if (NULL == self->buffers) {
		PyErr_NoMemory();
		return -1;
	}

	self->firstElements = PyMem_Malloc(size * sizeof(Py_ssize_t));
	if (NULL == self->firstElements) {
		PyMem_Free(self->buffers);
		self->buffers = NULL;
		PyErr_NoMemory();
		return -1;
	}

	self->bufferCount = size;

	for (i = 0; i < size; i++) {
		ZstdBufferWithSegments* item = (ZstdBufferWithSegments*)PyTuple_GET_ITEM(args, i);

		self->buffers[i] = item;
		Py_INCREF(item);

		if (i > 0) {
			self->firstElements[i - 1] = offset;
		}

		offset += item->segmentCount;
	}

	self->firstElements[size - 1] = offset;

	return 0;
}

static PyObject* BufferWithSegmentsCollection_size(ZstdBufferWithSegmentsCollection* self) {
	Py_ssize_t i;
	Py_ssize_t j;
	unsigned long long size = 0;

	for (i = 0; i < self->bufferCount; i++) {
		for (j = 0; j < self->buffers[i]->segmentCount; j++) {
			size += self->buffers[i]->segments[j].length;
		}
	}

	return PyLong_FromUnsignedLongLong(size);
}

Py_ssize_t BufferWithSegmentsCollection_length(ZstdBufferWithSegmentsCollection* self) {
	return self->firstElements[self->bufferCount - 1];
}

static ZstdBufferSegment* BufferWithSegmentsCollection_item(ZstdBufferWithSegmentsCollection* self, Py_ssize_t i) {
	Py_ssize_t bufferOffset;

	if (i < 0) {
		PyErr_SetString(PyExc_IndexError, "offset must be non-negative");
		return NULL;
	}

	if (i >= BufferWithSegmentsCollection_length(self)) {
		PyErr_Format(PyExc_IndexError, "offset must be less than %zd",
			BufferWithSegmentsCollection_length(self));
		return NULL;
	}

	for (bufferOffset = 0; bufferOffset < self->bufferCount; bufferOffset++) {
		Py_ssize_t offset = 0;

		if (i < self->firstElements[bufferOffset]) {
			if (bufferOffset > 0) {
				offset = self->firstElements[bufferOffset - 1];
			}

			return BufferWithSegments_item(self->buffers[bufferOffset], i - offset);
		}
	}

	PyErr_SetString(ZstdError, "error resolving segment; this should not happen");
	return NULL;
}

static PySequenceMethods BufferWithSegmentsCollection_sq = {
	(lenfunc)BufferWithSegmentsCollection_length, /* sq_length */
	0, /* sq_concat */
	0, /* sq_repeat */
	(ssizeargfunc)BufferWithSegmentsCollection_item, /* sq_item */
	0, /* sq_ass_item */
	0, /* sq_contains */
	0, /* sq_inplace_concat */
	0 /* sq_inplace_repeat */
};

static PyMethodDef BufferWithSegmentsCollection_methods[] = {
	{ "size", (PyCFunction)BufferWithSegmentsCollection_size,
	  METH_NOARGS, PyDoc_STR("total size in bytes of all segments") },
	{ NULL, NULL }
};

PyTypeObject ZstdBufferWithSegmentsCollectionType = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"zstd.BufferWithSegmentsCollection", /* tp_name */
	sizeof(ZstdBufferWithSegmentsCollection),/* tp_basicsize */
	0,                         /* tp_itemsize */
	(destructor)BufferWithSegmentsCollection_dealloc, /* tp_dealloc */
	0,                         /* tp_print */
	0,                         /* tp_getattr */
	0,                         /* tp_setattr */
	0,                         /* tp_compare */
	0,                         /* tp_repr */
	0,                         /* tp_as_number */
	&BufferWithSegmentsCollection_sq, /* tp_as_sequence */
	0,                         /* tp_as_mapping */
	0,                         /* tp_hash  */
	0,                         /* tp_call */
	0,                         /* tp_str */
	0,                         /* tp_getattro */
	0,                         /* tp_setattro */
	0,                         /* tp_as_buffer */
	Py_TPFLAGS_DEFAULT,        /* tp_flags */
	BufferWithSegmentsCollection__doc__, /* tp_doc */
	0,                         /* tp_traverse */
	0,                         /* tp_clear */
	0,                         /* tp_richcompare */
	0,                         /* tp_weaklistoffset */
	/* TODO implement iterator for performance. */
	0,                         /* tp_iter */
	0,                         /* tp_iternext */
	BufferWithSegmentsCollection_methods, /* tp_methods */
	0,                         /* tp_members */
	0,                         /* tp_getset */
	0,                         /* tp_base */
	0,                         /* tp_dict */
	0,                         /* tp_descr_get */
	0,                         /* tp_descr_set */
	0,                         /* tp_dictoffset */
	(initproc)BufferWithSegmentsCollection_init, /* tp_init */
	0,                         /* tp_alloc */
	PyType_GenericNew,         /* tp_new */
};

void bufferutil_module_init(PyObject* mod) {
	Py_TYPE(&ZstdBufferWithSegmentsType) = &PyType_Type;
	if (PyType_Ready(&ZstdBufferWithSegmentsType) < 0) {
		return;
	}

	Py_INCREF(&ZstdBufferWithSegmentsType);
	PyModule_AddObject(mod, "BufferWithSegments", (PyObject*)&ZstdBufferWithSegmentsType);

	Py_TYPE(&ZstdBufferSegmentsType) = &PyType_Type;
	if (PyType_Ready(&ZstdBufferSegmentsType) < 0) {
		return;
	}

	Py_INCREF(&ZstdBufferSegmentsType);
	PyModule_AddObject(mod, "BufferSegments", (PyObject*)&ZstdBufferSegmentsType);

	Py_TYPE(&ZstdBufferSegmentType) = &PyType_Type;
	if (PyType_Ready(&ZstdBufferSegmentType) < 0) {
		return;
	}

	Py_INCREF(&ZstdBufferSegmentType);
	PyModule_AddObject(mod, "BufferSegment", (PyObject*)&ZstdBufferSegmentType);

	Py_TYPE(&ZstdBufferWithSegmentsCollectionType) = &PyType_Type;
	if (PyType_Ready(&ZstdBufferWithSegmentsCollectionType) < 0) {
		return;
	}

	Py_INCREF(&ZstdBufferWithSegmentsCollectionType);
	PyModule_AddObject(mod, "BufferWithSegmentsCollection", (PyObject*)&ZstdBufferWithSegmentsCollectionType);
}