--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/contrib/python-zstandard/c-ext/decompressionreader.c Mon Apr 09 10:13:29 2018 -0700
@@ -0,0 +1,459 @@
+/**
+* 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;
+
+static void set_unsupported_operation(void) {
+ PyObject* iomod;
+ PyObject* exc;
+
+ iomod = PyImport_ImportModule("io");
+ if (NULL == iomod) {
+ return;
+ }
+
+ exc = PyObject_GetAttrString(iomod, "UnsupportedOperation");
+ if (NULL == exc) {
+ Py_DECREF(iomod);
+ return;
+ }
+
+ PyErr_SetNone(exc);
+ Py_DECREF(exc);
+ Py_DECREF(iomod);
+}
+
+static void reader_dealloc(ZstdDecompressionReader* self) {
+ Py_XDECREF(self->decompressor);
+ Py_XDECREF(self->reader);
+
+ if (self->buffer.buf) {
+ PyBuffer_Release(&self->buffer);
+ }
+
+ PyObject_Del(self);
+}
+
+static ZstdDecompressionReader* reader_enter(ZstdDecompressionReader* self) {
+ if (self->entered) {
+ PyErr_SetString(PyExc_ValueError, "cannot __enter__ multiple times");
+ return NULL;
+ }
+
+ if (ensure_dctx(self->decompressor, 1)) {
+ return NULL;
+ }
+
+ self->entered = 1;
+
+ Py_INCREF(self);
+ return self;
+}
+
+static PyObject* reader_exit(ZstdDecompressionReader* self, PyObject* args) {
+ PyObject* exc_type;
+ PyObject* exc_value;
+ PyObject* exc_tb;
+
+ if (!PyArg_ParseTuple(args, "OOO:__exit__", &exc_type, &exc_value, &exc_tb)) {
+ return NULL;
+ }
+
+ self->entered = 0;
+ self->closed = 1;
+
+ /* Release resources. */
+ Py_CLEAR(self->reader);
+ if (self->buffer.buf) {
+ PyBuffer_Release(&self->buffer);
+ memset(&self->buffer, 0, sizeof(self->buffer));
+ }
+
+ Py_CLEAR(self->decompressor);
+
+ Py_RETURN_FALSE;
+}
+
+static PyObject* reader_readable(PyObject* self) {
+ Py_RETURN_TRUE;
+}
+
+static PyObject* reader_writable(PyObject* self) {
+ Py_RETURN_FALSE;
+}
+
+static PyObject* reader_seekable(PyObject* self) {
+ Py_RETURN_TRUE;
+}
+
+static PyObject* reader_close(ZstdDecompressionReader* self) {
+ self->closed = 1;
+ Py_RETURN_NONE;
+}
+
+static PyObject* reader_closed(ZstdDecompressionReader* self) {
+ if (self->closed) {
+ Py_RETURN_TRUE;
+ }
+ else {
+ Py_RETURN_FALSE;
+ }
+}
+
+static PyObject* reader_flush(PyObject* self) {
+ Py_RETURN_NONE;
+}
+
+static PyObject* reader_isatty(PyObject* self) {
+ Py_RETURN_FALSE;
+}
+
+static PyObject* reader_read(ZstdDecompressionReader* self, PyObject* args, PyObject* kwargs) {
+ static char* kwlist[] = {
+ "size",
+ NULL
+ };
+
+ Py_ssize_t size = -1;
+ PyObject* result = NULL;
+ char* resultBuffer;
+ Py_ssize_t resultSize;
+ ZSTD_outBuffer output;
+ size_t zresult;
+
+ if (!self->entered) {
+ PyErr_SetString(ZstdError, "read() must be called from an active context manager");
+ return NULL;
+ }
+
+ if (self->closed) {
+ PyErr_SetString(PyExc_ValueError, "stream is closed");
+ return NULL;
+ }
+
+ if (self->finishedOutput) {
+ return PyBytes_FromStringAndSize("", 0);
+ }
+
+ if (!PyArg_ParseTupleAndKeywords(args, kwargs, "n", kwlist, &size)) {
+ return NULL;
+ }
+
+ if (size < 1) {
+ PyErr_SetString(PyExc_ValueError, "cannot read negative or size 0 amounts");
+ return NULL;
+ }
+
+ result = PyBytes_FromStringAndSize(NULL, size);
+ if (NULL == result) {
+ return NULL;
+ }
+
+ PyBytes_AsStringAndSize(result, &resultBuffer, &resultSize);
+
+ output.dst = resultBuffer;
+ output.size = resultSize;
+ output.pos = 0;
+
+readinput:
+
+ /* Consume input data left over from last time. */
+ if (self->input.pos < self->input.size) {
+ Py_BEGIN_ALLOW_THREADS
+ zresult = ZSTD_decompress_generic(self->decompressor->dctx,
+ &output, &self->input);
+ Py_END_ALLOW_THREADS
+
+ /* Input exhausted. Clear our state tracking. */
+ if (self->input.pos == self->input.size) {
+ memset(&self->input, 0, sizeof(self->input));
+ Py_CLEAR(self->readResult);
+
+ if (self->buffer.buf) {
+ self->finishedInput = 1;
+ }
+ }
+
+ if (ZSTD_isError(zresult)) {
+ PyErr_Format(ZstdError, "zstd decompress error: %s", ZSTD_getErrorName(zresult));
+ return NULL;
+ }
+ else if (0 == zresult) {
+ self->finishedOutput = 1;
+ }
+
+ /* We fulfilled the full read request. Emit it. */
+ if (output.pos && output.pos == output.size) {
+ self->bytesDecompressed += output.size;
+ return result;
+ }
+
+ /*
+ * There is more room in the output. Fall through to try to collect
+ * more data so we can try to fill the output.
+ */
+ }
+
+ if (!self->finishedInput) {
+ if (self->reader) {
+ Py_buffer buffer;
+
+ assert(self->readResult == NULL);
+ self->readResult = PyObject_CallMethod(self->reader, "read",
+ "k", self->readSize);
+ if (NULL == self->readResult) {
+ return NULL;
+ }
+
+ memset(&buffer, 0, sizeof(buffer));
+
+ if (0 != PyObject_GetBuffer(self->readResult, &buffer, PyBUF_CONTIG_RO)) {
+ return NULL;
+ }
+
+ /* EOF */
+ if (0 == buffer.len) {
+ self->finishedInput = 1;
+ Py_CLEAR(self->readResult);
+ }
+ else {
+ self->input.src = buffer.buf;
+ self->input.size = buffer.len;
+ self->input.pos = 0;
+ }
+
+ PyBuffer_Release(&buffer);
+ }
+ else {
+ assert(self->buffer.buf);
+ /*
+ * We should only get here once since above block will exhaust
+ * source buffer until finishedInput is set.
+ */
+ assert(self->input.src == NULL);
+
+ self->input.src = self->buffer.buf;
+ self->input.size = self->buffer.len;
+ self->input.pos = 0;
+ }
+ }
+
+ if (self->input.size) {
+ goto readinput;
+ }
+
+ /* EOF */
+ self->bytesDecompressed += output.pos;
+
+ if (safe_pybytes_resize(&result, output.pos)) {
+ Py_XDECREF(result);
+ return NULL;
+ }
+
+ return result;
+}
+
+static PyObject* reader_readall(PyObject* self) {
+ PyErr_SetNone(PyExc_NotImplementedError);
+ return NULL;
+}
+
+static PyObject* reader_readline(PyObject* self) {
+ PyErr_SetNone(PyExc_NotImplementedError);
+ return NULL;
+}
+
+static PyObject* reader_readlines(PyObject* self) {
+ PyErr_SetNone(PyExc_NotImplementedError);
+ return NULL;
+}
+
+static PyObject* reader_seek(ZstdDecompressionReader* self, PyObject* args) {
+ Py_ssize_t pos;
+ int whence = 0;
+ unsigned long long readAmount = 0;
+ size_t defaultOutSize = ZSTD_DStreamOutSize();
+
+ if (!self->entered) {
+ PyErr_SetString(ZstdError, "seek() must be called from an active context manager");
+ return NULL;
+ }
+
+ if (self->closed) {
+ PyErr_SetString(PyExc_ValueError, "stream is closed");
+ return NULL;
+ }
+
+ if (!PyArg_ParseTuple(args, "n|i:seek", &pos, &whence)) {
+ return NULL;
+ }
+
+ if (whence == SEEK_SET) {
+ if (pos < 0) {
+ PyErr_SetString(PyExc_ValueError,
+ "cannot seek to negative position with SEEK_SET");
+ return NULL;
+ }
+
+ if ((unsigned long long)pos < self->bytesDecompressed) {
+ PyErr_SetString(PyExc_ValueError,
+ "cannot seek zstd decompression stream backwards");
+ return NULL;
+ }
+
+ readAmount = pos - self->bytesDecompressed;
+ }
+ else if (whence == SEEK_CUR) {
+ if (pos < 0) {
+ PyErr_SetString(PyExc_ValueError,
+ "cannot seek zstd decompression stream backwards");
+ return NULL;
+ }
+
+ readAmount = pos;
+ }
+ else if (whence == SEEK_END) {
+ /* We /could/ support this with pos==0. But let's not do that until someone
+ needs it. */
+ PyErr_SetString(PyExc_ValueError,
+ "zstd decompression streams cannot be seeked with SEEK_END");
+ return NULL;
+ }
+
+ /* It is a bit inefficient to do this via the Python API. But since there
+ is a bit of state tracking involved to read from this type, it is the
+ easiest to implement. */
+ while (readAmount) {
+ Py_ssize_t readSize;
+ PyObject* readResult = PyObject_CallMethod((PyObject*)self, "read", "K",
+ readAmount < defaultOutSize ? readAmount : defaultOutSize);
+
+ if (!readResult) {
+ return NULL;
+ }
+
+ readSize = PyBytes_GET_SIZE(readResult);
+
+ /* Empty read means EOF. */
+ if (!readSize) {
+ break;
+ }
+
+ readAmount -= readSize;
+ }
+
+ return PyLong_FromUnsignedLongLong(self->bytesDecompressed);
+}
+
+static PyObject* reader_tell(ZstdDecompressionReader* self) {
+ /* TODO should this raise OSError since stream isn't seekable? */
+ return PyLong_FromUnsignedLongLong(self->bytesDecompressed);
+}
+
+static PyObject* reader_write(PyObject* self, PyObject* args) {
+ set_unsupported_operation();
+ return NULL;
+}
+
+static PyObject* reader_writelines(PyObject* self, PyObject* args) {
+ set_unsupported_operation();
+ return NULL;
+}
+
+static PyObject* reader_iter(PyObject* self) {
+ PyErr_SetNone(PyExc_NotImplementedError);
+ return NULL;
+}
+
+static PyObject* reader_iternext(PyObject* self) {
+ PyErr_SetNone(PyExc_NotImplementedError);
+ return NULL;
+}
+
+static PyMethodDef reader_methods[] = {
+ { "__enter__", (PyCFunction)reader_enter, METH_NOARGS,
+ PyDoc_STR("Enter a compression context") },
+ { "__exit__", (PyCFunction)reader_exit, METH_VARARGS,
+ PyDoc_STR("Exit a compression context") },
+ { "close", (PyCFunction)reader_close, METH_NOARGS,
+ PyDoc_STR("Close the stream so it cannot perform any more operations") },
+ { "closed", (PyCFunction)reader_closed, METH_NOARGS,
+ PyDoc_STR("Whether stream is closed") },
+ { "flush", (PyCFunction)reader_flush, METH_NOARGS, PyDoc_STR("no-ops") },
+ { "isatty", (PyCFunction)reader_isatty, METH_NOARGS, PyDoc_STR("Returns False") },
+ { "readable", (PyCFunction)reader_readable, METH_NOARGS,
+ PyDoc_STR("Returns True") },
+ { "read", (PyCFunction)reader_read, METH_VARARGS | METH_KEYWORDS,
+ PyDoc_STR("read compressed data") },
+ { "readall", (PyCFunction)reader_readall, METH_NOARGS, PyDoc_STR("Not implemented") },
+ { "readline", (PyCFunction)reader_readline, METH_NOARGS, PyDoc_STR("Not implemented") },
+ { "readlines", (PyCFunction)reader_readlines, METH_NOARGS, PyDoc_STR("Not implemented") },
+ { "seek", (PyCFunction)reader_seek, METH_VARARGS, PyDoc_STR("Seek the stream") },
+ { "seekable", (PyCFunction)reader_seekable, METH_NOARGS,
+ PyDoc_STR("Returns True") },
+ { "tell", (PyCFunction)reader_tell, METH_NOARGS,
+ PyDoc_STR("Returns current number of bytes compressed") },
+ { "writable", (PyCFunction)reader_writable, METH_NOARGS,
+ PyDoc_STR("Returns False") },
+ { "write", (PyCFunction)reader_write, METH_VARARGS, PyDoc_STR("unsupported operation") },
+ { "writelines", (PyCFunction)reader_writelines, METH_VARARGS, PyDoc_STR("unsupported operation") },
+ { NULL, NULL }
+};
+
+PyTypeObject ZstdDecompressionReaderType = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ "zstd.ZstdDecompressionReader", /* tp_name */
+ sizeof(ZstdDecompressionReader), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ (destructor)reader_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 */
+ 0, /* tp_doc */
+ 0, /* tp_traverse */
+ 0, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ reader_iter, /* tp_iter */
+ reader_iternext, /* tp_iternext */
+ reader_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 decompressionreader_module_init(PyObject* mod) {
+ /* TODO make reader a sub-class of io.RawIOBase */
+
+ Py_TYPE(&ZstdDecompressionReaderType) = &PyType_Type;
+ if (PyType_Ready(&ZstdDecompressionReaderType) < 0) {
+ return;
+ }
+}