/**

* 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;

PyDoc_STRVAR(ZstdCompresssionWriter__doc__,

"""A context manager used for writing compressed output to a writer.\n"

);

static void ZstdCompressionWriter_dealloc(ZstdCompressionWriter* self) {

	Py_XDECREF(self->compressor);

	Py_XDECREF(self->writer);

	if (self->cstream) {

		ZSTD_freeCStream(self->cstream);

		self->cstream = NULL;

	}

	PyObject_Del(self);

}

static PyObject* ZstdCompressionWriter_enter(ZstdCompressionWriter* self) {

	if (self->entered) {

		PyErr_SetString(ZstdError, "cannot __enter__ multiple times");

		return NULL;

	}

	self->cstream = CStream_from_ZstdCompressor(self->compressor, self->sourceSize);

	if (!self->cstream) {

		return NULL;

	}

	self->entered = 1;

	Py_INCREF(self);

	return (PyObject*)self;

}

static PyObject* ZstdCompressionWriter_exit(ZstdCompressionWriter* self, PyObject* args) {

	PyObject* exc_type;

	PyObject* exc_value;

	PyObject* exc_tb;

	size_t zresult;

	ZSTD_outBuffer output;

	PyObject* res;

	if (!PyArg_ParseTuple(args, "OOO", &exc_type, &exc_value, &exc_tb)) {

		return NULL;

	}

	self->entered = 0;

	if (self->cstream && exc_type == Py_None && exc_value == Py_None &&

		exc_tb == Py_None) {

		output.dst = malloc(self->outSize);

		if (!output.dst) {

			return PyErr_NoMemory();

		}

		output.size = self->outSize;

		output.pos = 0;

		while (1) {

			zresult = ZSTD_endStream(self->cstream, &output);

			if (ZSTD_isError(zresult)) {

				PyErr_Format(ZstdError, "error ending compression stream: %s",

					ZSTD_getErrorName(zresult));

				free(output.dst);

				return NULL;

			}

			if (output.pos) {

#if PY_MAJOR_VERSION >= 3

				res = PyObject_CallMethod(self->writer, "write", "y#",

#else

				res = PyObject_CallMethod(self->writer, "write", "s#",

#endif

					output.dst, output.pos);

				Py_XDECREF(res);

			}

			if (!zresult) {

				break;

			}

			output.pos = 0;

		}

		free(output.dst);

		ZSTD_freeCStream(self->cstream);

		self->cstream = NULL;

	}

	Py_RETURN_FALSE;

}

static PyObject* ZstdCompressionWriter_memory_size(ZstdCompressionWriter* self) {

	if (!self->cstream) {

		PyErr_SetString(ZstdError, "cannot determine size of an inactive compressor; "

			"call when a context manager is active");

		return NULL;

	}

	return PyLong_FromSize_t(ZSTD_sizeof_CStream(self->cstream));

}

static PyObject* ZstdCompressionWriter_write(ZstdCompressionWriter* self, PyObject* args) {

	const char* source;

	Py_ssize_t sourceSize;

	size_t zresult;

	ZSTD_inBuffer input;

	ZSTD_outBuffer output;

	PyObject* res;

#if PY_MAJOR_VERSION >= 3

	if (!PyArg_ParseTuple(args, "y#", &source, &sourceSize)) {

#else

	if (!PyArg_ParseTuple(args, "s#", &source, &sourceSize)) {

#endif

		return NULL;

	}

	if (!self->entered) {

		PyErr_SetString(ZstdError, "compress must be called from an active context manager");

		return NULL;

	}

	output.dst = malloc(self->outSize);

	if (!output.dst) {

		return PyErr_NoMemory();

	}

	output.size = self->outSize;

	output.pos = 0;

	input.src = source;

	input.size = sourceSize;

	input.pos = 0;

	while ((ssize_t)input.pos < sourceSize) {

		Py_BEGIN_ALLOW_THREADS

		zresult = ZSTD_compressStream(self->cstream, &output, &input);

		Py_END_ALLOW_THREADS

		if (ZSTD_isError(zresult)) {

			free(output.dst);

			PyErr_Format(ZstdError, "zstd compress error: %s", ZSTD_getErrorName(zresult));

			return NULL;

		}

		/* Copy data from output buffer to writer. */

		if (output.pos) {

#if PY_MAJOR_VERSION >= 3

			res = PyObject_CallMethod(self->writer, "write", "y#",

#else

			res = PyObject_CallMethod(self->writer, "write", "s#",

#endif

				output.dst, output.pos);

			Py_XDECREF(res);

		}

		output.pos = 0;

	}

	free(output.dst);

	/* TODO return bytes written */

	Py_RETURN_NONE;

	}

static PyMethodDef ZstdCompressionWriter_methods[] = {

	{ "__enter__", (PyCFunction)ZstdCompressionWriter_enter, METH_NOARGS,

	PyDoc_STR("Enter a compression context.") },

	{ "__exit__", (PyCFunction)ZstdCompressionWriter_exit, METH_VARARGS,

	PyDoc_STR("Exit a compression context.") },

	{ "memory_size", (PyCFunction)ZstdCompressionWriter_memory_size, METH_NOARGS,

	PyDoc_STR("Obtain the memory size of the underlying compressor") },

	{ "write", (PyCFunction)ZstdCompressionWriter_write, METH_VARARGS,

	PyDoc_STR("Compress data") },

	{ NULL, NULL }

};

PyTypeObject ZstdCompressionWriterType = {

	PyVarObject_HEAD_INIT(NULL, 0)

	"zstd.ZstdCompressionWriter",  /* tp_name */

	sizeof(ZstdCompressionWriter),  /* tp_basicsize */

	0,                              /* tp_itemsize */

	(destructor)ZstdCompressionWriter_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 | Py_TPFLAGS_BASETYPE, /* tp_flags */

	ZstdCompresssionWriter__doc__,  /* tp_doc */

	0,                              /* tp_traverse */

	0,                              /* tp_clear */

	0,                              /* tp_richcompare */

	0,                              /* tp_weaklistoffset */

	0,                              /* tp_iter */

	0,                              /* tp_iternext */

	ZstdCompressionWriter_methods,  /* tp_methods */

	0,                              /* 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 */

	PyType_GenericNew,              /* tp_new */

};

void compressionwriter_module_init(PyObject* mod) {

	Py_TYPE(&ZstdCompressionWriterType) = &PyType_Type;

	if (PyType_Ready(&ZstdCompressionWriterType) < 0) {

		return;

	}

}