1 files changed, 71 insertions, 0 deletions
diff --git a/include/sqfs/compress.h b/include/sqfs/compress.h
new file mode 100644
index 0000000..1dfba12
--- /dev/null
+++ b/include/sqfs/compress.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * compress.h
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#ifndef COMPRESS_H
+#define COMPRESS_H
+
+#include "config.h"
+
+#include <sys/types.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "squashfs.h"
+
+typedef struct compressor_t compressor_t;
+
+/* Encapsultes a compressor with a simple interface to compress or
+   uncompress/extract blocks of data. */
+struct compressor_t {
+	/* Write compressor options to the output file if necessary.
+	   Returns the number of bytes written or -1 on failure.
+	   Internally prints error messages to stderr. */
+	int (*write_options)(compressor_t *cmp, int fd);
+
+	/* Read compressor options to the input file.
+	   Returns zero on success, -1 on failure.
+	   Internally prints error messages to stderr. */
+	int (*read_options)(compressor_t *cmp, int fd);
+
+	/*
+	  Compress or uncompress a chunk of data.
+
+	  Returns the number of bytes written to the output buffer, -1 on
+	  failure or 0 if the output buffer was too small.
+	  The compressor also returns 0 if the compressed result ends
+	  up larger than the original input.
+
+	  Internally prints compressor specific error messages to stderr.
+	*/
+	ssize_t (*do_block)(compressor_t *cmp, const uint8_t *in, size_t size,
+			    uint8_t *out, size_t outsize);
+
+	/* create another compressor just like this one, i.e.
+	   with the exact same settings */
+	compressor_t *(*create_copy)(compressor_t *cmp);
+
+	void (*destroy)(compressor_t *stream);
+};
+
+bool compressor_exists(E_SQFS_COMPRESSOR id);
+
+/* block_size is the configured block size for the SquashFS image. Needed
+   by some compressors to set internal defaults. */
+compressor_t *compressor_create(E_SQFS_COMPRESSOR id, bool compress,
+				size_t block_size, char *options);
+
+void compressor_print_help(E_SQFS_COMPRESSOR id);
+
+void compressor_print_available(void);
+
+E_SQFS_COMPRESSOR compressor_get_default(void);
+
+const char *compressor_name_from_id(E_SQFS_COMPRESSOR id);
+
+int compressor_id_from_name(const char *name, E_SQFS_COMPRESSOR *out);
+
+#endif /* COMPRESS_H */