contrib/python-zstandard/c-ext/decompressobj.c

--- a/contrib/python-zstandard/c-ext/decompressobj.c	Tue Sep 25 20:55:03 2018 +0900
+++ b/contrib/python-zstandard/c-ext/decompressobj.c	Mon Oct 08 16:27:40 2018 -0700
@@ -33,6 +33,8 @@
 	PyObject* result = NULL;
 	Py_ssize_t resultSize = 0;
 
+	output.dst = NULL;
+
 	if (self->finished) {
 		PyErr_SetString(ZstdError, "cannot use a decompressobj multiple times");
 		return NULL;
@@ -53,6 +55,12 @@
 		goto finally;
 	}
 
+	/* Special case of empty input. Output will always be empty. */
+	if (source.len == 0) {
+		result = PyBytes_FromString("");
+		goto finally;
+	}
+
 	input.src = source.buf;
 	input.size = source.len;
 	input.pos = 0;
@@ -65,8 +73,7 @@
 	output.size = self->outSize;
 	output.pos = 0;
 
-	/* Read input until exhausted. */
-	while (input.pos < input.size) {
+	while (1) {
 		Py_BEGIN_ALLOW_THREADS
 		zresult = ZSTD_decompress_generic(self->decompressor->dctx, &output, &input);
 		Py_END_ALLOW_THREADS
@@ -98,9 +105,13 @@
 					goto except;
 				}
 			}
+		}
 
-			output.pos = 0;
+		if (zresult == 0 || (input.pos == input.size && output.pos == 0)) {
+			break;
 		}
+
+		output.pos = 0;
 	}
 
 	if (!result) {