zlib: initialize git_zstream in git_deflate_init{,_gzip,_raw}

Clear the git_zstream variable at the start of git_deflate_init() etc.
so that callers don't have to do that.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

archive-zip.c

@@ -120,7 +120,6 @@ static void *zlib_deflate_raw(void *data, unsigned long size,
 	void *buffer;
 	int result;
 
-	memset(&stream, 0, sizeof(stream));
 	git_deflate_init_raw(&stream, compression_level);
 	maxsize = git_deflate_bound(&stream, size);
 	buffer = xmalloc(maxsize);
@@ -349,7 +348,6 @@ static int write_zip_entry(struct archiver_args *args,
 		size_t out_len;
 		unsigned char compressed[STREAM_BUFFER_SIZE * 2];
 
-		memset(&zstream, 0, sizeof(zstream));
 		git_deflate_init_raw(&zstream, args->compression_level);
 
 		compressed_size = 0;

builtin/index-pack.c

@@ -1173,7 +1173,6 @@ static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 	int status;
 	unsigned char outbuf[4096];
 
-	memset(&stream, 0, sizeof(stream));
 	git_deflate_init(&stream, zlib_compression_level);
 	stream.next_in = in;
 	stream.avail_in = size;

builtin/pack-objects.c

@@ -123,7 +123,6 @@ static unsigned long do_compress(void **pptr, unsigned long size)
 	void *in, *out;
 	unsigned long maxsize;
 
-	memset(&stream, 0, sizeof(stream));
 	git_deflate_init(&stream, pack_compression_level);
 	maxsize = git_deflate_bound(&stream, size);
 
@@ -151,7 +150,6 @@ static unsigned long write_large_blob_data(struct git_istream *st, struct sha1fi
 	unsigned char obuf[1024 * 16];
 	unsigned long olen = 0;
 
-	memset(&stream, 0, sizeof(stream));
 	git_deflate_init(&stream, pack_compression_level);
 
 	for (;;) {

bulk-checkin.c

@@ -104,7 +104,6 @@ static int stream_to_pack(struct bulk_checkin_state *state,
 	int write_object = (flags & HASH_WRITE_OBJECT);
 	off_t offset = 0;
 
-	memset(&s, 0, sizeof(s));
 	git_deflate_init(&s, pack_compression_level);
 
 	hdrlen = encode_in_pack_object_header(type, size, obuf);

diff.c

@@ -2091,7 +2091,6 @@ static unsigned char *deflate_it(char *data,
 	unsigned char *deflated;
 	git_zstream stream;
 
-	memset(&stream, 0, sizeof(stream));
 	git_deflate_init(&stream, zlib_compression_level);
 	bound = git_deflate_bound(&stream, size);
 	deflated = xmalloc(bound);

fast-import.c

@@ -1053,7 +1053,6 @@ static int store_object(
 	} else
 		delta = NULL;
 
-	memset(&s, 0, sizeof(s));
 	git_deflate_init(&s, pack_compression_level);
 	if (delta) {
 		s.next_in = delta;
@@ -1081,7 +1080,6 @@ static int store_object(
 			free(delta);
 			delta = NULL;
 
-			memset(&s, 0, sizeof(s));
 			git_deflate_init(&s, pack_compression_level);
 			s.next_in = (void *)dat->buf;
 			s.avail_in = dat->len;
@@ -1181,7 +1179,6 @@ static void stream_blob(uintmax_t len, unsigned char *sha1out, uintmax_t mark)
 
 	crc32_begin(pack_file);
 
-	memset(&s, 0, sizeof(s));
 	git_deflate_init(&s, pack_compression_level);
 
 	hdrlen = encode_in_pack_object_header(OBJ_BLOB, len, out_buf);

http-push.c

@@ -365,7 +365,6 @@ static void start_put(struct transfer_request *request)
 	hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
 
 	/* Set it up */
-	memset(&stream, 0, sizeof(stream));
 	git_deflate_init(&stream, zlib_compression_level);
 	size = git_deflate_bound(&stream, len + hdrlen);
 	strbuf_init(&request->buffer.buf, size);

remote-curl.c

@@ -555,7 +555,6 @@ retry:
 		git_zstream stream;
 		int ret;
 
-		memset(&stream, 0, sizeof(stream));
 		git_deflate_init_gzip(&stream, Z_BEST_COMPRESSION);
 		gzip_size = git_deflate_bound(&stream, rpc->len);
 		gzip_body = xmalloc(gzip_size);

sha1_file.c

@@ -2916,7 +2916,6 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
 	}
 
 	/* Set it up */
-	memset(&stream, 0, sizeof(stream));
 	git_deflate_init(&stream, zlib_compression_level);
 	stream.next_out = compressed;
 	stream.avail_out = sizeof(compressed);

zlib.c

@@ -159,6 +159,7 @@ void git_deflate_init(git_zstream *strm, int level)
 {
 	int status;
 
+	memset(strm, 0, sizeof(*strm));
 	zlib_pre_call(strm);
 	status = deflateInit(&strm->z, level);
 	zlib_post_call(strm);
@@ -172,6 +173,7 @@ static void do_git_deflate_init(git_zstream *strm, int level, int windowBits)
 {
 	int status;
 
+	memset(strm, 0, sizeof(*strm));
 	zlib_pre_call(strm);
 	status = deflateInit2(&strm->z, level,
 				  Z_DEFLATED, windowBits,