view contrib/python-zstandard/c-ext/frameparams.c @ 46370:cad17d50736c

changelog: move branchinfo to changelogrevision

The function parses the extra dictionary after looking up the
changelogrevision. To avoid duplicated look up, it is better to provide
it as property of changelogrevision instead. Keep the function for a
release cycle as at least the topic extension depends on it.

Differential Revision: https://phab.mercurial-scm.org/D9779

/**
* 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(FrameParameters__doc__,
	"FrameParameters: information about a zstd frame");

FrameParametersObject* get_frame_parameters(PyObject* self, PyObject* args, PyObject* kwargs) {
	static char* kwlist[] = {
		"data",
		NULL
	};

	Py_buffer source;
	ZSTD_frameHeader header;
	FrameParametersObject* result = NULL;
	size_t zresult;

#if PY_MAJOR_VERSION >= 3
	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "y*:get_frame_parameters",
#else
	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s*:get_frame_parameters",
#endif
		kwlist, &source)) {
		return NULL;
	}

	if (!PyBuffer_IsContiguous(&source, 'C') || source.ndim > 1) {
		PyErr_SetString(PyExc_ValueError,
			"data buffer should be contiguous and have at most one dimension");
		goto finally;
	}

	zresult = ZSTD_getFrameHeader(&header, source.buf, source.len);

	if (ZSTD_isError(zresult)) {
		PyErr_Format(ZstdError, "cannot get frame parameters: %s", ZSTD_getErrorName(zresult));
		goto finally;
	}

	if (zresult) {
		PyErr_Format(ZstdError, "not enough data for frame parameters; need %zu bytes", zresult);
		goto finally;
	}

	result = PyObject_New(FrameParametersObject, &FrameParametersType);
	if (!result) {
		goto finally;
	}

	result->frameContentSize = header.frameContentSize;
	result->windowSize = header.windowSize;
	result->dictID = header.dictID;
	result->checksumFlag = header.checksumFlag ? 1 : 0;

finally:
	PyBuffer_Release(&source);
	return result;
}

static void FrameParameters_dealloc(PyObject* self) {
	PyObject_Del(self);
}

static PyMemberDef FrameParameters_members[] = {
	{ "content_size", T_ULONGLONG,
	  offsetof(FrameParametersObject, frameContentSize), READONLY,
	  "frame content size" },
	{ "window_size", T_ULONGLONG,
	  offsetof(FrameParametersObject, windowSize), READONLY,
	  "window size" },
	{ "dict_id", T_UINT,
	  offsetof(FrameParametersObject, dictID), READONLY,
	  "dictionary ID" },
	{ "has_checksum", T_BOOL,
	  offsetof(FrameParametersObject, checksumFlag), READONLY,
	  "checksum flag" },
	{ NULL }
};

PyTypeObject FrameParametersType = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"FrameParameters",          /* tp_name */
	sizeof(FrameParametersObject), /* tp_basicsize */
	0,                         /* tp_itemsize */
	(destructor)FrameParameters_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 */
	0,                         /* tp_as_buffer */
	Py_TPFLAGS_DEFAULT,        /* tp_flags */
	FrameParameters__doc__,    /* tp_doc */
	0,                         /* tp_traverse */
	0,                         /* tp_clear */
	0,                         /* tp_richcompare */
	0,                         /* tp_weaklistoffset */
	0,                         /* tp_iter */
	0,                         /* tp_iternext */
	0,                         /* tp_methods */
	FrameParameters_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 */
	0,                         /* tp_new */
};

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

	Py_INCREF(&FrameParametersType);
	PyModule_AddObject(mod, "FrameParameters", (PyObject*)&FrameParametersType);
}