patches from Andrew
NOTE: There is still a bug of some sort in the behavior of zlib. In
at least one case, inflate returns Z_OK (which is typically
interpreted to mean that more output space is needed) when it has
finished inflating a buffer. This has been reported as a bug to the
zlib maintainers; we may need to change the Python interface.
diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index 9cfcbb7..43e59c5 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -80,7 +80,7 @@
"Can't allocate memory to compress data");
return NULL;
}
- zst.zalloc=(alloc_func)NULL;
+
zst.zfree=(free_func)Z_NULL;
zst.next_out=(Byte *)output;
zst.next_in =(Byte *)input;
@@ -172,7 +172,7 @@
if (r_strlen <= 0)
r_strlen = 1;
-
+
zst.avail_in=length;
zst.avail_out=r_strlen;
if (!(result_str = PyString_FromStringAndSize(NULL, r_strlen)))
@@ -212,6 +212,8 @@
do
{
err=inflate(&zst, Z_FINISH);
+ fprintf(stderr, "err=%d avail_in=%d avail_out=%d\n",
+ err, zst.avail_in, zst.avail_out);
switch(err)
{
case(Z_STREAM_END):
@@ -488,8 +490,11 @@
}
static char comp_flush__doc__[] =
-"flush() -- Return a string containing any remaining compressed data. "
-"The compressor object can no longer be used after this call."
+"flush( [mode] ) -- Return a string containing any remaining compressed data.\n"
+"mode can be one of the constants Z_SYNC_FLUSH, Z_FULL_FLUSH, Z_FINISH; the \n"
+"default value used when mode is not specified is Z_FINISH.\n"
+"If mode == Z_FINISH, the compressor object can no longer be used after\n"
+"calling the flush() method. Otherwise, more data can still be compressed.\n"
;
static PyObject *
@@ -499,9 +504,19 @@
{
int length=DEFAULTALLOC, err = Z_OK;
PyObject *RetVal;
-
- if (!PyArg_NoArgs(args))
+ int flushmode = Z_FINISH;
+ unsigned long start_total_out;
+
+ if (!PyArg_ParseTuple(args, "|i", &flushmode))
return NULL;
+
+ /* Flushing with Z_NO_FLUSH is a no-op, so there's no point in
+ doing any work at all; just return an empty string. */
+ if (flushmode == Z_NO_FLUSH)
+ {
+ return PyString_FromStringAndSize(NULL, 0);
+ }
+
self->zst.avail_in = 0;
self->zst.next_in = Z_NULL;
if (!(RetVal = PyString_FromStringAndSize(NULL, length))) {
@@ -509,10 +524,14 @@
"Can't allocate memory to compress data");
return NULL;
}
+ start_total_out = self->zst.total_out;
self->zst.next_out = (unsigned char *)PyString_AsString(RetVal);
self->zst.avail_out = length;
- while (err == Z_OK)
- {
+
+ /* When flushing the zstream, there's no input data.
+ If zst.avail_out == 0, that means that more output space is
+ needed to complete the flush operation. */
+ do {
err = deflate(&(self->zst), Z_FINISH);
if (self->zst.avail_out <= 0) {
if (_PyString_Resize(&RetVal, length << 1) == -1) {
@@ -524,31 +543,34 @@
self->zst.avail_out = length;
length = length << 1;
}
- }
- if (err!=Z_STREAM_END) {
+ } while (self->zst.avail_out == 0);
+
+ if (err!=Z_OK && err != Z_STREAM_END)
+ {
if (self->zst.msg == Z_NULL)
- PyErr_Format(ZlibError, "Error %i while compressing",
+ PyErr_Format(ZlibError, "Error %i while flushing",
err);
else
- PyErr_Format(ZlibError, "Error %i while compressing: %.200s",
+ PyErr_Format(ZlibError, "Error %i while flushing: %.200s",
err, self->zst.msg);
Py_DECREF(RetVal);
return NULL;
- }
- err=deflateEnd(&(self->zst));
- if (err!=Z_OK) {
+ }
+ if (flushmode == Z_FINISH) {
+ err=deflateEnd(&(self->zst));
+ if (err!=Z_OK) {
if (self->zst.msg == Z_NULL)
- PyErr_Format(ZlibError, "Error %i while flushing compression object",
- err);
+ PyErr_Format(ZlibError, "Error %i from deflateEnd()",
+ err);
else
- PyErr_Format(ZlibError,
- "Error %i while flushing compression object: %.200s",
- err, self->zst.msg);
+ PyErr_Format(ZlibError,
+ "Error %i from deflateEnd(): %.200s",
+ err, self->zst.msg);
Py_DECREF(RetVal);
return NULL;
+ }
}
- _PyString_Resize(&RetVal,
- (char *)self->zst.next_out - PyString_AsString(RetVal));
+ _PyString_Resize(&RetVal, self->zst.total_out - start_total_out);
return RetVal;
}
@@ -627,7 +649,7 @@
static PyMethodDef comp_methods[] =
{
{"compress", (binaryfunc)PyZlib_objcompress, 1, comp_compress__doc__},
- {"flush", (binaryfunc)PyZlib_flush, 0, comp_flush__doc__},
+ {"flush", (binaryfunc)PyZlib_flush, 1, comp_flush__doc__},
{NULL, NULL}
};
@@ -805,6 +827,12 @@
insint(d, "Z_FILTERED", Z_FILTERED);
insint(d, "Z_HUFFMAN_ONLY", Z_HUFFMAN_ONLY);
insint(d, "Z_DEFAULT_STRATEGY", Z_DEFAULT_STRATEGY);
+
+ insint(d, "Z_FINISH", Z_FINISH);
+ insint(d, "Z_NO_FLUSH", Z_NO_FLUSH);
+ insint(d, "Z_SYNC_FLUSH", Z_SYNC_FLUSH);
+ insint(d, "Z_FULL_FLUSH", Z_FULL_FLUSH);
+
ver = PyString_FromString(ZLIB_VERSION);
PyDict_SetItemString(d, "ZLIB_VERSION", ver);
}