1 files changed, 49 insertions, 0 deletions
diff --git a/mozglue/linker/XZStream.h b/mozglue/linker/XZStream.h
new file mode 100644
index 0000000000..bab5520e37
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+++ b/mozglue/linker/XZStream.h
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef XZSTREAM_h
+#define XZSTREAM_h
+
+#include <cstdlib>
+#include <stdint.h>
+
+#define XZ_DEC_DYNALLOC
+#include "xz.h"
+
+// Used to decode XZ stream buffers.
+class XZStream {
+ public:
+  // Returns whether the provided buffer is likely a XZ stream.
+  static bool IsXZ(const void* aBuf, size_t aBufSize);
+
+  // Creates a XZ stream object for the given input buffer.
+  XZStream(const void* aInBuf, size_t aInSize);
+  ~XZStream();
+
+  // Initializes the decoder and returns whether decoding may commence.
+  bool Init();
+  // Decodes the next chunk of input into the given output buffer.
+  size_t Decode(void* aOutBuf, size_t aOutSize);
+  // Returns the number of yet undecoded bytes in the input buffer.
+  size_t RemainingInput() const;
+  // Returns the total number of bytes in the input buffer (compressed size).
+  size_t Size() const;
+  // Returns the expected final number of bytes in the output buffer.
+  // Note: will return 0 before successful Init().
+  size_t UncompressedSize() const;
+
+ private:
+  // Parses the stream footer and returns the size of the index in bytes.
+  size_t ParseIndexSize() const;
+  // Parses the stream index and returns the expected uncompressed size in
+  // bytes.
+  size_t ParseUncompressedSize() const;
+
+  const uint8_t* mInBuf;
+  size_t mUncompSize;
+  xz_buf mBuffers;
+  xz_dec* mDec;
+};
+
+#endif  // XZSTREAM_h