Imported to git.

1 files changed, 143 insertions, 0 deletions

diff --git a/src/liblzma/common/copy_coder.c b/src/liblzma/common/copy_coder.c
new file mode 100644
index 00000000..64864f60
--- /dev/null
+++ b/src/liblzma/common/copy_coder.c
@@ -0,0 +1,143 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       copy_coder.c
+/// \brief      The Copy filter encoder and decoder
+//
+//  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 "copy_coder.h"
+
+
+struct lzma_coder_s {
+	lzma_next_coder next;
+	lzma_vli uncompressed_size;
+	bool is_encoder;
+};
+
+
+static lzma_ret
+copy_code(lzma_coder *coder, lzma_allocator *allocator,
+		const uint8_t *restrict in, size_t *restrict in_pos,
+		size_t in_size, uint8_t *restrict out,
+		size_t *restrict out_pos, size_t out_size, lzma_action action)
+{
+	// If we aren't the last filter in the chain, the Copy filter
+	// is totally useless. Note that it is job of the next coder to
+	// take care of Uncompressed Size, so we don't need to update our
+	// coder->uncompressed_size at all.
+	if (coder->next.code != NULL)
+		return coder->next.code(coder->next.coder, allocator,
+				in, in_pos, in_size, out, out_pos, out_size,
+				action);
+
+	// If we get here, we are the last filter in the chain.
+
+	const size_t in_avail = in_size - *in_pos;
+
+	if (coder->is_encoder) {
+		// Check that we don't have too much input.
+		if ((lzma_vli)(in_avail) > coder->uncompressed_size)
+			return LZMA_DATA_ERROR;
+
+		// Check that once LZMA_FINISH has been given, the
+		// amount of input matches uncompressed_size if it
+		// is known.
+		if (action == LZMA_FINISH && coder->uncompressed_size
+					!= LZMA_VLI_VALUE_UNKNOWN
+				&& coder->uncompressed_size
+					!= (lzma_vli)(in_avail))
+			return LZMA_DATA_ERROR;
+
+	} else {
+		// Limit in_size so that we don't copy too much.
+		if ((lzma_vli)(in_avail) > coder->uncompressed_size)
+			in_size = *in_pos + (size_t)(coder->uncompressed_size);
+	}
+
+	// Store the old input position, which is needed to update
+	// coder->uncompressed_size.
+	const size_t in_start = *in_pos;
+
+	// We are the last coder in the chain.
+	// Just copy as much data as possible.
+	bufcpy(in, in_pos, in_size, out, out_pos, out_size);
+
+	// Update uncompressed_size if it is known.
+	if (coder->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN)
+		coder->uncompressed_size -= *in_pos - in_start;
+
+	// action can be LZMA_FINISH only in the encoder.
+	if ((action == LZMA_FINISH && *in_pos == in_size)
+			|| coder->uncompressed_size == 0)
+		return LZMA_STREAM_END;
+
+	return LZMA_OK;
+}
+
+
+static void
+copy_coder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+	lzma_next_coder_end(&coder->next, allocator);
+	lzma_free(coder, allocator);
+	return;
+}
+
+
+static lzma_ret
+copy_coder_init(lzma_next_coder *next, lzma_allocator *allocator,
+		const lzma_filter_info *filters, bool is_encoder)
+{
+	// Allocate memory for the decoder if needed.
+	if (next->coder == NULL) {
+		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+		if (next->coder == NULL)
+			return LZMA_MEM_ERROR;
+
+		next->code = &copy_code;
+		next->end = &copy_coder_end;
+		next->coder->next = LZMA_NEXT_CODER_INIT;
+	}
+
+	// Copy Uncompressed Size which is used to limit the output size.
+	next->coder->uncompressed_size = filters[0].uncompressed_size;
+
+	// The coder acts slightly differently as encoder and decoder.
+	next->coder->is_encoder = is_encoder;
+
+	// Initialize the next decoder in the chain, if any.
+	return lzma_next_filter_init(
+			&next->coder->next, allocator, filters + 1);
+}
+
+
+#ifdef HAVE_ENCODER
+extern lzma_ret
+lzma_copy_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+		const lzma_filter_info *filters)
+{
+	lzma_next_coder_init(copy_coder_init, next, allocator, filters, true);
+}
+#endif
+
+
+#ifdef HAVE_DECODER
+extern lzma_ret
+lzma_copy_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+		const lzma_filter_info *filters)
+{
+	lzma_next_coder_init(copy_coder_init, next, allocator, filters, false);
+}
+#endif