Fixed the flush() method of compression objects; the test for
the end of loop was incorrect, and failed when the flushmode != Z_FINISH.
Logic cleaned up and commented.
diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index 81a9cd4..486c0ed 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -541,21 +541,34 @@
/* 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. */
- while (err == Z_OK) {
- err = deflate(&(self->zst), Z_FINISH);
- if (self->zst.avail_out <= 0) {
- if (_PyString_Resize(&RetVal, length << 1) == -1) {
- PyErr_SetString(PyExc_MemoryError,
- "Can't allocate memory to compress data");
- return NULL;
- }
- self->zst.next_out = (unsigned char *)PyString_AsString(RetVal) + length;
- self->zst.avail_out = length;
- length = length << 1;
+ while (1) {
+ err = deflate(&(self->zst), flushmode);
+
+ /* If the output is Z_OK, and there's still room in the output
+ buffer, then the flush is complete. */
+ if ( (err == Z_OK) && self->zst.avail_out > 0) break;
+
+ /* A nonzero return indicates some sort of error (but see
+ the comment for the error handler below) */
+ if ( err != Z_OK ) break;
+
+ /* There's no space left for output, so increase the buffer and loop
+ again */
+ if (_PyString_Resize(&RetVal, length << 1) == -1) {
+ PyErr_SetString(PyExc_MemoryError,
+ "Can't allocate memory to compress data");
+ return NULL;
}
+ self->zst.next_out = (unsigned char *)PyString_AsString(RetVal) + length;
+ self->zst.avail_out = length;
+ length = length << 1;
}
- if (err != Z_STREAM_END)
+ /* Raise an exception indicating an error. The condition for
+ detecting a error is kind of complicated; Z_OK indicates no
+ error, but if the flushmode is Z_FINISH, then Z_STREAM_END is
+ also not an error. */
+ if (err!=Z_OK && !(flushmode == Z_FINISH && err == Z_STREAM_END) )
{
if (self->zst.msg == Z_NULL)
PyErr_Format(ZlibError, "Error %i while flushing",
@@ -566,6 +579,10 @@
Py_DECREF(RetVal);
return NULL;
}
+
+ /* If flushmode is Z_FINISH, we also have to call deflateEnd() to
+ free various data structures */
+
if (flushmode == Z_FINISH) {
err=deflateEnd(&(self->zst));
if (err!=Z_OK) {