1 files changed, 65 insertions, 0 deletions
diff --git a/src/liblzma/common/next_coder.c b/src/liblzma/common/next_coder.c
new file mode 100644
index 00000000..c10fe24d
--- /dev/null
+++ b/src/liblzma/common/next_coder.c
@@ -0,0 +1,65 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       next_coder.c
+/// \brief      Initializing and freeing the next coder in the chain
+//
+//  Copyright (C) 2007 Lasse Collin
+//
+//  This library is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Lesser General Public
+//  License as published by the Free Software Foundation; either
+//  version 2.1 of the License, or (at your option) any later version.
+//
+//  This library is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  Lesser General Public License for more details.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "common.h"
+
+extern lzma_ret
+lzma_next_filter_init(lzma_next_coder *next, lzma_allocator *allocator,
+		const lzma_filter_info *filters)
+{
+	lzma_ret ret = LZMA_OK;
+
+	// Free the existing coder if it is different than the current one.
+	if ((uintptr_t)(filters[0].init) != next->init)
+		lzma_next_coder_end(next, allocator);
+
+	if (filters[0].init != NULL) {
+		// Initialize the new coder.
+		ret = filters[0].init(next, allocator, filters);
+
+		// Set the init function pointer if initialization was
+		// successful. next->code and next->end are set by the
+		// initialization function itself.
+		if (ret == LZMA_OK) {
+			next->init = (uintptr_t)(filters[0].init);
+			assert(next->code != NULL);
+			assert(next->end != NULL);
+		} else {
+			lzma_next_coder_end(next, allocator);
+		}
+	}
+
+	return ret;
+}
+
+
+extern void
+lzma_next_coder_end(lzma_next_coder *next, lzma_allocator *allocator)
+{
+	if (next != NULL) {
+		if (next->end != NULL)
+			next->end(next->coder, allocator);
+
+		// Reset the variables so the we don't accidentally think
+		// that it is an already initialized coder.
+		*next = LZMA_NEXT_CODER_INIT;
+	}
+
+	return;
+}