view contrib/python-zstandard/zstd.c @ 31736:dd2079fae003

largefiles: add copytostore() fstandin argument to replace readstandin() (API)

copyalltostore(), only one caller of copytostore(), already knows
standin file name of the target largefile. Therefore, passing it to
copytostore() is more efficient than calculating it in copytostore()
or readstandin().

/**
 * 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. */

#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");

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

static PyMethodDef zstd_methods[] = {
	{ "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__ },
	{ NULL, NULL }
};

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 dictparams_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;
	}

	compressionparams_module_init(m);
	dictparams_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