annotate contrib/python-zstandard/c-ext/constants.c @ 31796:e0dc40530c5a

zstd: vendor python-zstandard 0.8.0

Commit 81e1f5bbf1fc54808649562d3ed829730765c540 from
https://github.com/indygreg/python-zstandard is imported without
modifications (other than removing unwanted files).

Updates relevant to Mercurial include:

* Support for multi-threaded compression (we can use this for
  bundle and wire protocol compression).
* APIs for batch compression and decompression operations using
  multiple threads and optimal memory allocation mechanism. (Can
  be useful for revlog perf improvements.)
* A ``BufferWithSegments`` type that models a single memory buffer
  containing N discrete items of known lengths. This type can be
  used for very efficient 0-copy data operations.

# no-check-commit

/**
* 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.
*/

#include "python-zstandard.h"

extern PyObject* ZstdError;

static char frame_header[] = {
	'\x28',
	'\xb5',
	'\x2f',
	'\xfd',
};

void constants_module_init(PyObject* mod) {
	PyObject* version;
	PyObject* zstdVersion;
	PyObject* frameHeader;

#if PY_MAJOR_VERSION >= 3
	version = PyUnicode_FromString(PYTHON_ZSTANDARD_VERSION);
#else
	version = PyString_FromString(PYTHON_ZSTANDARD_VERSION);
#endif
	Py_INCREF(version);
	PyModule_AddObject(mod, "__version__", version);

	ZstdError = PyErr_NewException("zstd.ZstdError", NULL, NULL);
	PyModule_AddObject(mod, "ZstdError", ZstdError);

	PyModule_AddIntConstant(mod, "COMPRESSOBJ_FLUSH_FINISH", compressorobj_flush_finish);
	PyModule_AddIntConstant(mod, "COMPRESSOBJ_FLUSH_BLOCK", compressorobj_flush_block);

	/* For now, the version is a simple tuple instead of a dedicated type. */
	zstdVersion = PyTuple_New(3);
	PyTuple_SetItem(zstdVersion, 0, PyLong_FromLong(ZSTD_VERSION_MAJOR));
	PyTuple_SetItem(zstdVersion, 1, PyLong_FromLong(ZSTD_VERSION_MINOR));
	PyTuple_SetItem(zstdVersion, 2, PyLong_FromLong(ZSTD_VERSION_RELEASE));
	Py_INCREF(zstdVersion);
	PyModule_AddObject(mod, "ZSTD_VERSION", zstdVersion);

	frameHeader = PyBytes_FromStringAndSize(frame_header, sizeof(frame_header));
	if (frameHeader) {
		PyModule_AddObject(mod, "FRAME_HEADER", frameHeader);
	}
	else {
		PyErr_Format(PyExc_ValueError, "could not create frame header object");
	}

	PyModule_AddIntConstant(mod, "MAX_COMPRESSION_LEVEL", ZSTD_maxCLevel());
	PyModule_AddIntConstant(mod, "COMPRESSION_RECOMMENDED_INPUT_SIZE",
		(long)ZSTD_CStreamInSize());
	PyModule_AddIntConstant(mod, "COMPRESSION_RECOMMENDED_OUTPUT_SIZE",
		(long)ZSTD_CStreamOutSize());
	PyModule_AddIntConstant(mod, "DECOMPRESSION_RECOMMENDED_INPUT_SIZE",
		(long)ZSTD_DStreamInSize());
	PyModule_AddIntConstant(mod, "DECOMPRESSION_RECOMMENDED_OUTPUT_SIZE",
		(long)ZSTD_DStreamOutSize());

	PyModule_AddIntConstant(mod, "MAGIC_NUMBER", ZSTD_MAGICNUMBER);
	PyModule_AddIntConstant(mod, "WINDOWLOG_MIN", ZSTD_WINDOWLOG_MIN);
	PyModule_AddIntConstant(mod, "WINDOWLOG_MAX", ZSTD_WINDOWLOG_MAX);
	PyModule_AddIntConstant(mod, "CHAINLOG_MIN", ZSTD_CHAINLOG_MIN);
	PyModule_AddIntConstant(mod, "CHAINLOG_MAX", ZSTD_CHAINLOG_MAX);
	PyModule_AddIntConstant(mod, "HASHLOG_MIN", ZSTD_HASHLOG_MIN);
	PyModule_AddIntConstant(mod, "HASHLOG_MAX", ZSTD_HASHLOG_MAX);
	PyModule_AddIntConstant(mod, "HASHLOG3_MAX", ZSTD_HASHLOG3_MAX);
	PyModule_AddIntConstant(mod, "SEARCHLOG_MIN", ZSTD_SEARCHLOG_MIN);
	PyModule_AddIntConstant(mod, "SEARCHLOG_MAX", ZSTD_SEARCHLOG_MAX);
	PyModule_AddIntConstant(mod, "SEARCHLENGTH_MIN", ZSTD_SEARCHLENGTH_MIN);
	PyModule_AddIntConstant(mod, "SEARCHLENGTH_MAX", ZSTD_SEARCHLENGTH_MAX);
	PyModule_AddIntConstant(mod, "TARGETLENGTH_MIN", ZSTD_TARGETLENGTH_MIN);
	PyModule_AddIntConstant(mod, "TARGETLENGTH_MAX", ZSTD_TARGETLENGTH_MAX);

	PyModule_AddIntConstant(mod, "STRATEGY_FAST", ZSTD_fast);
	PyModule_AddIntConstant(mod, "STRATEGY_DFAST", ZSTD_dfast);
	PyModule_AddIntConstant(mod, "STRATEGY_GREEDY", ZSTD_greedy);
	PyModule_AddIntConstant(mod, "STRATEGY_LAZY", ZSTD_lazy);
	PyModule_AddIntConstant(mod, "STRATEGY_LAZY2", ZSTD_lazy2);
	PyModule_AddIntConstant(mod, "STRATEGY_BTLAZY2", ZSTD_btlazy2);
	PyModule_AddIntConstant(mod, "STRATEGY_BTOPT", ZSTD_btopt);
}