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Issue #14684: Add support for predefined compression dictionaries to the zlib module.
Original patch by Sam Rushing.
This commit is contained in:
Nadeem Vawda
parent
50b0a365ba
commit
fd8a838d58
4 changed files with 152 additions and 28 deletions
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@ -45,6 +45,7 @@ typedef struct
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PyObject *unconsumed_tail;
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char eof;
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int is_initialised;
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PyObject *zdict;
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#ifdef WITH_THREAD
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PyThread_type_lock lock;
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#endif
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@ -80,14 +81,21 @@ zlib_error(z_stream zst, int err, char *msg)
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}
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PyDoc_STRVAR(compressobj__doc__,
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"compressobj([level]) -- Return a compressor object.\n"
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"compressobj([level[, method[, wbits[, memlevel[, strategy[, zdict]]]]]])\n"
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" -- Return a compressor object.\n"
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"\n"
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"Optional arg level is the compression level, in 1-9.");
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"Optional arg level is the compression level, in 1-9.\n"
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"\n"
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"Optional arg zdict is the predefined compression dictionary - a sequence of\n"
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"bytes containing subsequences that are likely to occur in the input data.");
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PyDoc_STRVAR(decompressobj__doc__,
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"decompressobj([wbits]) -- Return a decompressor object.\n"
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"decompressobj([wbits[, zdict]]) -- Return a decompressor object.\n"
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"\n"
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"Optional arg wbits is the window buffer size.");
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"Optional arg wbits is the window buffer size.\n"
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"\n"
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"Optional arg zdict is the predefined compression dictionary. This must be\n"
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"the same dictionary as used by the compressor that produced the input data.");
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static compobject *
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newcompobject(PyTypeObject *type)
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@ -98,6 +106,7 @@ newcompobject(PyTypeObject *type)
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return NULL;
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self->eof = 0;
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self->is_initialised = 0;
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self->zdict = NULL;
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self->unused_data = PyBytes_FromStringAndSize("", 0);
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if (self->unused_data == NULL) {
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Py_DECREF(self);
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@ -316,19 +325,24 @@ PyZlib_decompress(PyObject *self, PyObject *args)
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}
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static PyObject *
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PyZlib_compressobj(PyObject *selfptr, PyObject *args)
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PyZlib_compressobj(PyObject *selfptr, PyObject *args, PyObject *kwargs)
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{
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compobject *self;
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int level=Z_DEFAULT_COMPRESSION, method=DEFLATED;
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int wbits=MAX_WBITS, memLevel=DEF_MEM_LEVEL, strategy=0, err;
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Py_buffer zdict;
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static char *kwlist[] = {"level", "method", "wbits",
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"memLevel", "strategy", "zdict", NULL};
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if (!PyArg_ParseTuple(args, "|iiiii:compressobj", &level, &method, &wbits,
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&memLevel, &strategy))
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zdict.buf = NULL; /* Sentinel, so we can tell whether zdict was supplied. */
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if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|iiiiiy*:compressobj",
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kwlist, &level, &method, &wbits,
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&memLevel, &strategy, &zdict))
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return NULL;
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self = newcompobject(&Comptype);
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if (self==NULL)
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return(NULL);
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goto error;
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self->zst.zalloc = (alloc_func)NULL;
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self->zst.zfree = (free_func)Z_NULL;
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self->zst.next_in = NULL;
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@ -337,30 +351,58 @@ PyZlib_compressobj(PyObject *selfptr, PyObject *args)
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switch(err) {
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case (Z_OK):
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self->is_initialised = 1;
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return (PyObject*)self;
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if (zdict.buf == NULL) {
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goto success;
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} else {
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err = deflateSetDictionary(&self->zst, zdict.buf, zdict.len);
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switch (err) {
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case (Z_OK):
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goto success;
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case (Z_STREAM_ERROR):
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PyErr_SetString(PyExc_ValueError, "Invalid dictionary");
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goto error;
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default:
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PyErr_SetString(PyExc_ValueError, "deflateSetDictionary()");
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goto error;
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}
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}
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case (Z_MEM_ERROR):
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Py_DECREF(self);
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PyErr_SetString(PyExc_MemoryError,
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"Can't allocate memory for compression object");
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return NULL;
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goto error;
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case(Z_STREAM_ERROR):
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Py_DECREF(self);
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PyErr_SetString(PyExc_ValueError, "Invalid initialization option");
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return NULL;
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goto error;
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default:
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zlib_error(self->zst, err, "while creating compression object");
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Py_DECREF(self);
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return NULL;
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goto error;
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}
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error:
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Py_XDECREF(self);
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self = NULL;
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success:
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if (zdict.buf != NULL)
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PyBuffer_Release(&zdict);
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return (PyObject*)self;
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}
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static PyObject *
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PyZlib_decompressobj(PyObject *selfptr, PyObject *args)
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PyZlib_decompressobj(PyObject *selfptr, PyObject *args, PyObject *kwargs)
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{
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static char *kwlist[] = {"wbits", "zdict", NULL};
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int wbits=DEF_WBITS, err;
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compobject *self;
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if (!PyArg_ParseTuple(args, "|i:decompressobj", &wbits))
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PyObject *zdict=NULL;
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if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|iO:decompressobj",
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kwlist, &wbits, &zdict))
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return NULL;
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if (zdict != NULL && !PyObject_CheckBuffer(zdict)) {
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PyErr_SetString(PyExc_TypeError,
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"zdict argument must support the buffer protocol");
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return NULL;
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}
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self = newcompobject(&Decomptype);
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if (self == NULL)
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@ -369,6 +411,10 @@ PyZlib_decompressobj(PyObject *selfptr, PyObject *args)
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self->zst.zfree = (free_func)Z_NULL;
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self->zst.next_in = NULL;
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self->zst.avail_in = 0;
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if (zdict != NULL) {
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Py_INCREF(zdict);
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self->zdict = zdict;
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}
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err = inflateInit2(&self->zst, wbits);
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switch(err) {
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case (Z_OK):
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@ -398,6 +444,7 @@ Dealloc(compobject *self)
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#endif
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Py_XDECREF(self->unused_data);
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Py_XDECREF(self->unconsumed_tail);
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Py_XDECREF(self->zdict);
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PyObject_Del(self);
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}
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@ -557,6 +604,27 @@ PyZlib_objdecompress(compobject *self, PyObject *args)
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err = inflate(&(self->zst), Z_SYNC_FLUSH);
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Py_END_ALLOW_THREADS
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if (err == Z_NEED_DICT && self->zdict != NULL) {
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Py_buffer zdict_buf;
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if (PyObject_GetBuffer(self->zdict, &zdict_buf, PyBUF_SIMPLE) == -1) {
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Py_DECREF(RetVal);
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RetVal = NULL;
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goto error;
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}
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err = inflateSetDictionary(&(self->zst), zdict_buf.buf, zdict_buf.len);
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PyBuffer_Release(&zdict_buf);
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if (err != Z_OK) {
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zlib_error(self->zst, err, "while decompressing data");
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Py_DECREF(RetVal);
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RetVal = NULL;
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goto error;
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}
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/* repeat the call to inflate! */
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Py_BEGIN_ALLOW_THREADS
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err = inflate(&(self->zst), Z_SYNC_FLUSH);
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Py_END_ALLOW_THREADS
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}
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/* While Z_OK and the output buffer is full, there might be more output.
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So extend the output buffer and try again.
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*/
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@ -770,10 +838,13 @@ PyZlib_copy(compobject *self)
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}
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Py_INCREF(self->unused_data);
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Py_INCREF(self->unconsumed_tail);
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Py_XINCREF(self->zdict);
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Py_XDECREF(retval->unused_data);
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Py_XDECREF(retval->unconsumed_tail);
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Py_XDECREF(retval->zdict);
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retval->unused_data = self->unused_data;
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retval->unconsumed_tail = self->unconsumed_tail;
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retval->zdict = self->zdict;
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retval->eof = self->eof;
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/* Mark it as being initialized */
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@ -822,10 +893,13 @@ PyZlib_uncopy(compobject *self)
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Py_INCREF(self->unused_data);
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Py_INCREF(self->unconsumed_tail);
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Py_XINCREF(self->zdict);
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Py_XDECREF(retval->unused_data);
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Py_XDECREF(retval->unconsumed_tail);
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Py_XDECREF(retval->zdict);
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retval->unused_data = self->unused_data;
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retval->unconsumed_tail = self->unconsumed_tail;
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retval->zdict = self->zdict;
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retval->eof = self->eof;
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/* Mark it as being initialized */
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@ -1032,13 +1106,13 @@ static PyMethodDef zlib_methods[] =
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adler32__doc__},
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{"compress", (PyCFunction)PyZlib_compress, METH_VARARGS,
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compress__doc__},
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{"compressobj", (PyCFunction)PyZlib_compressobj, METH_VARARGS,
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{"compressobj", (PyCFunction)PyZlib_compressobj, METH_VARARGS|METH_KEYWORDS,
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compressobj__doc__},
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{"crc32", (PyCFunction)PyZlib_crc32, METH_VARARGS,
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crc32__doc__},
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{"decompress", (PyCFunction)PyZlib_decompress, METH_VARARGS,
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decompress__doc__},
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{"decompressobj", (PyCFunction)PyZlib_decompressobj, METH_VARARGS,
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{"decompressobj", (PyCFunction)PyZlib_decompressobj, METH_VARARGS|METH_KEYWORDS,
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decompressobj__doc__},
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{NULL, NULL}
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};
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@ -1112,10 +1186,10 @@ PyDoc_STRVAR(zlib_module_documentation,
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"\n"
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"adler32(string[, start]) -- Compute an Adler-32 checksum.\n"
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"compress(string[, level]) -- Compress string, with compression level in 1-9.\n"
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"compressobj([level]) -- Return a compressor object.\n"
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"compressobj([level[, ...]]) -- Return a compressor object.\n"
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"crc32(string[, start]) -- Compute a CRC-32 checksum.\n"
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"decompress(string,[wbits],[bufsize]) -- Decompresses a compressed string.\n"
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"decompressobj([wbits]) -- Return a decompressor object.\n"
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"decompressobj([wbits[, zdict]]]) -- Return a decompressor object.\n"
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"\n"
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"'wbits' is window buffer size.\n"
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"Compressor objects support compress() and flush() methods; decompressor\n"
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