/**

 * Copyright (c) 2016-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.

 */

/* A Python C extension for Zstandard. */

#if defined(_WIN32)

#define WIN32_LEAN_AND_MEAN

#include <Windows.h>

#elif defined(__APPLE__) || defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__DragonFly__)

#include <sys/types.h>

#include <sys/sysctl.h>

#endif

#include "python-zstandard.h"

PyObject *ZstdError;

PyDoc_STRVAR(estimate_compression_context_size__doc__,

"estimate_compression_context_size(compression_parameters)\n"

"\n"

"Give the amount of memory allocated for a compression context given a\n"

"CompressionParameters instance");

PyDoc_STRVAR(estimate_decompression_context_size__doc__,

"estimate_decompression_context_size()\n"

"\n"

"Estimate the amount of memory allocated to a decompression context.\n"

);

static PyObject* estimate_decompression_context_size(PyObject* self) {

	return PyLong_FromSize_t(ZSTD_estimateDCtxSize());

}

PyDoc_STRVAR(get_compression_parameters__doc__,

"get_compression_parameters(compression_level[, source_size[, dict_size]])\n"

"\n"

"Obtains a ``CompressionParameters`` instance from a compression level and\n"

"optional input size and dictionary size");

PyDoc_STRVAR(get_frame_parameters__doc__,

"get_frame_parameters(data)\n"

"\n"

"Obtains a ``FrameParameters`` instance by parsing data.\n");

PyDoc_STRVAR(train_dictionary__doc__,

"train_dictionary(dict_size, samples)\n"

"\n"

"Train a dictionary from sample data.\n"

"\n"

"A compression dictionary of size ``dict_size`` will be created from the\n"

"iterable of samples provided by ``samples``.\n"

"\n"

"The raw dictionary content will be returned\n");

PyDoc_STRVAR(train_cover_dictionary__doc__,

"train_cover_dictionary(dict_size, samples, k=None, d=None, notifications=0, dict_id=0, level=0)\n"

"\n"

"Train a dictionary from sample data using the COVER algorithm.\n"

"\n"

"This behaves like ``train_dictionary()`` except a different algorithm is\n"

"used to create the dictionary. The algorithm has 2 parameters: ``k`` and\n"

"``d``. These control the *segment size* and *dmer size*. A reasonable range\n"

"for ``k`` is ``[16, 2048+]``. A reasonable range for ``d`` is ``[6, 16]``.\n"

"``d`` must be less than or equal to ``k``.\n"

);

static char zstd_doc[] = "Interface to zstandard";

static PyMethodDef zstd_methods[] = {

	/* TODO remove since it is a method on CompressionParameters. */

	{ "estimate_compression_context_size", (PyCFunction)estimate_compression_context_size,

	METH_VARARGS, estimate_compression_context_size__doc__ },

	{ "estimate_decompression_context_size", (PyCFunction)estimate_decompression_context_size,

	METH_NOARGS, estimate_decompression_context_size__doc__ },

	{ "get_compression_parameters", (PyCFunction)get_compression_parameters,

	METH_VARARGS, get_compression_parameters__doc__ },

	{ "get_frame_parameters", (PyCFunction)get_frame_parameters,

	METH_VARARGS, get_frame_parameters__doc__ },

	{ "train_dictionary", (PyCFunction)train_dictionary,

	METH_VARARGS | METH_KEYWORDS, train_dictionary__doc__ },

	{ "train_cover_dictionary", (PyCFunction)train_cover_dictionary,

	METH_VARARGS | METH_KEYWORDS, train_cover_dictionary__doc__ },

	{ NULL, NULL }

};

void bufferutil_module_init(PyObject* mod);

void compressobj_module_init(PyObject* mod);

void compressor_module_init(PyObject* mod);

void compressionparams_module_init(PyObject* mod);

void constants_module_init(PyObject* mod);

void compressiondict_module_init(PyObject* mod);

void compressionwriter_module_init(PyObject* mod);

void compressoriterator_module_init(PyObject* mod);

void decompressor_module_init(PyObject* mod);

void decompressobj_module_init(PyObject* mod);

void decompressionwriter_module_init(PyObject* mod);

void decompressoriterator_module_init(PyObject* mod);

void frameparams_module_init(PyObject* mod);

void zstd_module_init(PyObject* m) {

	/* python-zstandard relies on unstable zstd C API features. This means

	   that changes in zstd may break expectations in python-zstandard.

	   python-zstandard is distributed with a copy of the zstd sources.

	   python-zstandard is only guaranteed to work with the bundled version

	   of zstd.

	   However, downstream redistributors or packagers may unbundle zstd

	   from python-zstandard. This can result in a mismatch between zstd

	   versions and API semantics. This essentially "voids the warranty"

	   of python-zstandard and may cause undefined behavior.

	   We detect this mismatch here and refuse to load the module if this

	   scenario is detected.

	*/

	if (ZSTD_VERSION_NUMBER != 10103 || ZSTD_versionNumber() != 10103) {

		PyErr_SetString(PyExc_ImportError, "zstd C API mismatch; Python bindings not compiled against expected zstd version");

		return;

	}

	bufferutil_module_init(m);

	compressionparams_module_init(m);

	compressiondict_module_init(m);

	compressobj_module_init(m);

	compressor_module_init(m);

	compressionwriter_module_init(m);

	compressoriterator_module_init(m);

	constants_module_init(m);

	decompressor_module_init(m);

	decompressobj_module_init(m);

	decompressionwriter_module_init(m);

	decompressoriterator_module_init(m);

	frameparams_module_init(m);

}

#if PY_MAJOR_VERSION >= 3

static struct PyModuleDef zstd_module = {

	PyModuleDef_HEAD_INIT,

	"zstd",

	zstd_doc,

	-1,

	zstd_methods

};

PyMODINIT_FUNC PyInit_zstd(void) {

	PyObject *m = PyModule_Create(&zstd_module);

	if (m) {

		zstd_module_init(m);

		if (PyErr_Occurred()) {

			Py_DECREF(m);

			m = NULL;

		}

	}

	return m;

}

#else

PyMODINIT_FUNC initzstd(void) {

	PyObject *m = Py_InitModule3("zstd", zstd_methods, zstd_doc);

	if (m) {

		zstd_module_init(m);

	}

}

#endif

/* Attempt to resolve the number of CPUs in the system. */

int cpu_count() {

	int count = 0;

#if defined(_WIN32)

	SYSTEM_INFO si;

	si.dwNumberOfProcessors = 0;

	GetSystemInfo(&si);

	count = si.dwNumberOfProcessors;

#elif defined(__APPLE__)

	int num;

	size_t size = sizeof(int);

	if (0 == sysctlbyname("hw.logicalcpu", &num, &size, NULL, 0)) {

		count = num;

	}

#elif defined(__linux__)

	count = sysconf(_SC_NPROCESSORS_ONLN);

#elif defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__DragonFly__)

	int mib[2];

	size_t len = sizeof(count);

	mib[0] = CTL_HW;

	mib[1] = HW_NCPU;

	if (0 != sysctl(mib, 2, &count, &len, NULL, 0)) {

		count = 0;

	}

#elif defined(__hpux)

	count = mpctl(MPC_GETNUMSPUS, NULL, NULL);

#endif

	return count;

}

size_t roundpow2(size_t i) {

	i--;

	i |= i >> 1;

	i |= i >> 2;

	i |= i >> 4;

	i |= i >> 8;

	i |= i >> 16;

	i++;

	return i;

}