view contrib/python-zstandard/c-ext/frameparams.c @ 48085:6a78715e56c8

dirstate: add a `get_entry` method to the dirstate

This method give access to the underlying `DirstateEntry` object (or an empty
one if None was there). It should allow us to use the more semantic property of
the entry instead of the state where we needs it.

Differential Revision: https://phab.mercurial-scm.org/D11522

/**
* 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_SET_TYPE(&FrameParametersType, &PyType_Type);
	if (PyType_Ready(&FrameParametersType) < 0) {
		return;
	}

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