1 files changed, 95 insertions, 0 deletions
diff --git a/src/zstream.c b/src/zstream.c
new file mode 100644
index 000000000..7def0440b
--- /dev/null
+++ b/src/zstream.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include <zlib.h>
+
+#include "zstream.h"
+#include "buffer.h"
+
+#define BUFFER_SIZE (1024 * 1024)
+
+static int zstream_seterr(int zerr, git_zstream *zstream)
+{
+	if (zerr == Z_MEM_ERROR)
+		giterr_set_oom();
+	else if (zstream->msg)
+		giterr_set(GITERR_ZLIB, zstream->msg);
+	else
+		giterr_set(GITERR_ZLIB, "Unknown compression error");
+
+	return -1;
+}
+
+int git_zstream_init(git_zstream *zstream)
+{
+	int zerr;
+
+	if ((zerr = deflateInit(zstream, Z_DEFAULT_COMPRESSION)) != Z_OK)
+		return zstream_seterr(zerr, zstream);
+
+	return 0;
+}
+
+ssize_t git_zstream_deflate(void *out, size_t out_len, git_zstream *zstream, const void *in, size_t in_len)
+{
+	int zerr;
+
+	if ((ssize_t)out_len < 0)
+		out_len = INT_MAX;
+
+	zstream->next_in = (Bytef *)in;
+	zstream->avail_in = in_len;
+	zstream->next_out = out;
+	zstream->avail_out = out_len;
+
+	if ((zerr = deflate(zstream, Z_FINISH)) == Z_STREAM_ERROR)
+		return zstream_seterr(zerr, zstream);
+
+	return (out_len - zstream->avail_out);
+}
+
+void git_zstream_reset(git_zstream *zstream)
+{
+	deflateReset(zstream);
+}
+
+void git_zstream_free(git_zstream *zstream)
+{
+	deflateEnd(zstream);
+}
+
+int git_zstream_deflatebuf(git_buf *out, const void *in, size_t in_len)
+{
+	git_zstream zstream = GIT_ZSTREAM_INIT;
+	size_t out_len;
+	ssize_t written;
+	int error = 0;
+
+	if ((error = git_zstream_init(&zstream)) < 0)
+		goto done;
+
+	do {
+		if (out->asize - out->size < BUFFER_SIZE)
+			git_buf_grow(out, out->asize + BUFFER_SIZE);
+
+		out_len = out->asize - out->size;
+
+		if ((written = git_zstream_deflate(out->ptr + out->size, out_len, &zstream, in, in_len)) <= 0)
+			break;
+
+		in = (char *)in + written;
+		in_len -= written;
+		out->size += written;
+	} while (written > 0);
+
+	if (written < 0)
+		error = written;
+
+done:
+	git_zstream_free(&zstream);
+	return error;
+}