1 files changed, 128 insertions, 0 deletions
diff --git a/include/io/xfrm.h b/include/io/xfrm.h
new file mode 100644
index 0000000..22a42b6
--- /dev/null
+++ b/include/io/xfrm.h
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * xfrm.h
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#ifndef IO_XFRM_H
+#define IO_XFRM_H
+
+#include "io/istream.h"
+#include "io/ostream.h"
+
+enum {
+	/**
+	 * @brief Deflate compressor with gzip headers.
+	 *
+	 * This actually creates a gzip compatible file, including a
+	 * gzip header and trailer.
+	 */
+	IO_COMPRESSOR_GZIP = 1,
+
+	IO_COMPRESSOR_XZ = 2,
+
+	IO_COMPRESSOR_ZSTD = 3,
+
+	IO_COMPRESSOR_BZIP2 = 4,
+
+	IO_COMPRESSOR_MIN = 1,
+	IO_COMPRESSOR_MAX = 4,
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Create an input stream that transparently uncompresses data.
+ *
+ * @memberof istream_t
+ *
+ * This function creates an input stream that wraps an underlying input stream
+ * that is compressed and transparently uncompresses the data when reading
+ * from it.
+ *
+ * The new stream takes ownership of the wrapped stream and destroys it when
+ * the compressor stream is destroyed. If this function fails, the wrapped
+ * stream is also destroyed.
+ *
+ * @param strm A pointer to another stream that should be wrapped.
+ * @param comp_id An identifier describing the compressor to use.
+ *
+ * @return A pointer to an input stream on success, NULL on failure.
+ */
+SQFS_INTERNAL istream_t *istream_compressor_create(istream_t *strm,
+						   int comp_id);
+
+/**
+ * @brief Create an output stream that transparently compresses data.
+ *
+ * @memberof ostream_t
+ *
+ * This function creates an output stream that transparently compresses all
+ * data appended to it and writes the compressed data to an underlying, wrapped
+ * output stream.
+ *
+ * The new stream takes ownership of the wrapped stream and destroys it when
+ * the compressor stream is destroyed. If this function fails, the wrapped
+ * stream is also destroyed.
+ *
+ * @param strm A pointer to another stream that should be wrapped.
+ * @param comp_id An identifier describing the compressor to use.
+ *
+ * @return A pointer to an output stream on success, NULL on failure.
+ */
+SQFS_INTERNAL ostream_t *ostream_compressor_create(ostream_t *strm,
+						   int comp_id);
+
+/**
+ * @brief Probe the buffered data in an istream to check if it is compressed.
+ *
+ * @memberof istream_t
+ *
+ * This function peeks into the internal buffer of an input stream to check
+ * for magic signatures of various compressors.
+ *
+ * @param strm A pointer to an input stream to check
+ * @param probe A callback used to check if raw/decoded data matches an
+ *              expected format. Returns 0 if not, -1 on failure and +1
+ *              on success.
+ *
+ * @return A compressor ID on success, 0 if no match was found, -1 on failure.
+ */
+SQFS_INTERNAL int istream_detect_compressor(istream_t *strm,
+					    int (*probe)(const sqfs_u8 *data,
+							 size_t size));
+
+/**
+ * @brief Resolve a compressor name to an ID.
+ *
+ * @param name A compressor name.
+ *
+ * @return A compressor ID on success, -1 on failure.
+ */
+SQFS_INTERNAL int io_compressor_id_from_name(const char *name);
+
+/**
+ * @brief Resolve a id to a  compressor name.
+ *
+ * @param id A compressor ID.
+ *
+ * @return A compressor name on success, NULL on failure.
+ */
+SQFS_INTERNAL const char *io_compressor_name_from_id(int id);
+
+/**
+ * @brief Check if support for a given compressor has been built in.
+ *
+ * @param id A compressor ID.
+ *
+ * @return True if the compressor is supported, false if not.
+ */
+SQFS_INTERNAL bool io_compressor_exists(int id);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* IO_XFRM_H */