Coverity scan error -Resource leak (RESOURCE_LEAK)- in gzippedDataWithCompressionLevel function

[sarigavs-jeppesen]

Getting error CID 262312: (#1 of 1): Resource leak (RESOURCE_LEAK)
5. leaked_storage: Variable stream going out of scope leaks the storage stream.state points to. in
'- (NSData *)gzippedDataWithCompressionLevel:(float)level' function while running Coverity scan tool.

Find the below code with comments(in bold) from Coverity tool

2- (NSData )gzippedDataWithCompressionLevel:(float)level
43{
1. Condition ({...; self->length(__coverity_objc_sel_name_length);}) == 0, taking false branch.
2. Condition self->isGzippedData(coverity_objc_sel_name_isGzippedData), taking false branch.
44 if (self.length == 0 || [self isGzippedData])
45 {
46 return self;
47 }
48
49 z_stream stream;
50 stream.zalloc = Z_NULL;
51 stream.zfree = Z_NULL;
52 stream.opaque = Z_NULL;
53 stream.avail_in = (uint)self.length;
54 stream.next_in = (Bytef *)(void *)self.bytes;
55 stream.total_out = 0;
56 stream.avail_out = 0;
57
58 static const NSUInteger ChunkSize = 16384;
59
60 NSMutableData *output = nil;
61 int compression = (level < 0.0f)? Z_DEFAULT_COMPRESSION: (int)(roundf(level * 9));
3. alloc_arg: deflateInit2 allocates memory that is stored into stream.state.
4. Condition deflateInit2(&stream, compression, 8, 31, 8, 0, "1.2.12" / "1.2.12" /, 112 / (int)sizeof (z_stream) */) == 0, taking false branch.
62 if (deflateInit2(&stream, compression, Z_DEFLATED, 31, 8, Z_DEFAULT_STRATEGY) == Z_OK)
63 {
64 output = [NSMutableData dataWithLength:ChunkSize];
65 while (stream.avail_out == 0)
66 {
67 if (stream.total_out >= output.length)
68 {
69 output.length += ChunkSize;
70 }
71 stream.next_out = (uint8_t *)output.mutableBytes + stream.total_out;
72 stream.avail_out = (uInt)(output.length - stream.total_out);
CID 239929:Unchecked return value from library (CHECKED_RETURN) [ "select issue" ]
73 deflate(&stream, Z_FINISH);
74 }
75 deflateEnd(&stream);
76 output.length = stream.total_out;
77 }
78

CID 262312: (#1 of 1): Resource leak (RESOURCE_LEAK)
5. leaked_storage: Variable stream going out of scope leaks the storage stream.state points to.
79 return output;
80}