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/**
* 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"
#define min(a, b) (((a) < (b)) ? (a) : (b))
extern PyObject* ZstdError;
PyDoc_STRVAR(ZstdCompressorIterator__doc__,
"Represents an iterator of compressed data.\n"
);
static void ZstdCompressorIterator_dealloc(ZstdCompressorIterator* self) {
Py_XDECREF(self->readResult);
Py_XDECREF(self->compressor);
Py_XDECREF(self->reader);
if (self->buffer.buf) {
PyBuffer_Release(&self->buffer);
memset(&self->buffer, 0, sizeof(self->buffer));
}
if (self->output.dst) {
PyMem_Free(self->output.dst);
self->output.dst = NULL;
}
PyObject_Del(self);
}
static PyObject* ZstdCompressorIterator_iter(PyObject* self) {
Py_INCREF(self);
return self;
}
static PyObject* ZstdCompressorIterator_iternext(ZstdCompressorIterator* self) {
size_t zresult;
PyObject* readResult = NULL;
PyObject* chunk;
char* readBuffer;
Py_ssize_t readSize = 0;
Py_ssize_t bufferRemaining;
if (self->finishedOutput) {
PyErr_SetString(PyExc_StopIteration, "output flushed");
return NULL;
}
feedcompressor:
/* If we have data left in the input, consume it. */
if (self->input.pos < self->input.size) {
Py_BEGIN_ALLOW_THREADS
zresult = ZSTD_compressStream2(self->compressor->cctx, &self->output,
&self->input, ZSTD_e_continue);
Py_END_ALLOW_THREADS
/* Release the Python object holding the input buffer. */
if (self->input.pos == self->input.size) {
self->input.src = NULL;
self->input.pos = 0;
self->input.size = 0;
Py_DECREF(self->readResult);
self->readResult = NULL;
}
if (ZSTD_isError(zresult)) {
PyErr_Format(ZstdError, "zstd compress error: %s", ZSTD_getErrorName(zresult));
return NULL;
}
/* If it produced output data, emit it. */
if (self->output.pos) {
chunk = PyBytes_FromStringAndSize(self->output.dst, self->output.pos);
self->output.pos = 0;
return chunk;
}
}
/* We should never have output data sitting around after a previous call. */
assert(self->output.pos == 0);
/* The code above should have either emitted a chunk and returned or consumed
the entire input buffer. So the state of the input buffer is not
relevant. */
if (!self->finishedInput) {
if (self->reader) {
readResult = PyObject_CallMethod(self->reader, "read", "I", self->inSize);
if (!readResult) {
PyErr_SetString(ZstdError, "could not read() from source");
return NULL;
}
PyBytes_AsStringAndSize(readResult, &readBuffer, &readSize);
}
else {
assert(self->buffer.buf);
/* Only support contiguous C arrays. */
assert(self->buffer.strides == NULL && self->buffer.suboffsets == NULL);
assert(self->buffer.itemsize == 1);
readBuffer = (char*)self->buffer.buf + self->bufferOffset;
bufferRemaining = self->buffer.len - self->bufferOffset;
readSize = min(bufferRemaining, (Py_ssize_t)self->inSize);
self->bufferOffset += readSize;
}
if (0 == readSize) {
Py_XDECREF(readResult);
self->finishedInput = 1;
}
else {
self->readResult = readResult;
}
}
/* EOF */
if (0 == readSize) {
self->input.src = NULL;
self->input.size = 0;
self->input.pos = 0;
zresult = ZSTD_compressStream2(self->compressor->cctx, &self->output,
&self->input, ZSTD_e_end);
if (ZSTD_isError(zresult)) {
PyErr_Format(ZstdError, "error ending compression stream: %s",
ZSTD_getErrorName(zresult));
return NULL;
}
assert(self->output.pos);
if (0 == zresult) {
self->finishedOutput = 1;
}
chunk = PyBytes_FromStringAndSize(self->output.dst, self->output.pos);
self->output.pos = 0;
return chunk;
}
/* New data from reader. Feed into compressor. */
self->input.src = readBuffer;
self->input.size = readSize;
self->input.pos = 0;
Py_BEGIN_ALLOW_THREADS
zresult = ZSTD_compressStream2(self->compressor->cctx, &self->output,
&self->input, ZSTD_e_continue);
Py_END_ALLOW_THREADS
/* The input buffer currently points to memory managed by Python
(readBuffer). This object was allocated by this function. If it wasn't
fully consumed, we need to release it in a subsequent function call.
If it is fully consumed, do that now.
*/
if (self->input.pos == self->input.size) {
self->input.src = NULL;
self->input.pos = 0;
self->input.size = 0;
Py_XDECREF(self->readResult);
self->readResult = NULL;
}
if (ZSTD_isError(zresult)) {
PyErr_Format(ZstdError, "zstd compress error: %s", ZSTD_getErrorName(zresult));
return NULL;
}
assert(self->input.pos <= self->input.size);
/* If we didn't write anything, start the process over. */
if (0 == self->output.pos) {
goto feedcompressor;
}
chunk = PyBytes_FromStringAndSize(self->output.dst, self->output.pos);
self->output.pos = 0;
return chunk;
}
PyTypeObject ZstdCompressorIteratorType = {
PyVarObject_HEAD_INIT(NULL, 0)
"zstd.ZstdCompressorIterator", /* tp_name */
sizeof(ZstdCompressorIterator), /* tp_basicsize */
0, /* tp_itemsize */
(destructor)ZstdCompressorIterator_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 */
ZstdCompressorIterator__doc__, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
ZstdCompressorIterator_iter, /* tp_iter */
(iternextfunc)ZstdCompressorIterator_iternext, /* tp_iternext */
0, /* 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 compressoriterator_module_init(PyObject* mod) {
Py_TYPE(&ZstdCompressorIteratorType) = &PyType_Type;
if (PyType_Ready(&ZstdCompressorIteratorType) < 0) {
return;
}
}
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