Add some single-call buffer-to-buffer coding functions.

1 files changed, 138 insertions, 0 deletions

diff --git a/src/liblzma/common/stream_buffer_encoder.c b/src/liblzma/common/stream_buffer_encoder.c
new file mode 100644
index 00000000..29588365
--- /dev/null
+++ b/src/liblzma/common/stream_buffer_encoder.c
@@ -0,0 +1,138 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       stream_buffer_encoder.c
+/// \brief      Single-call .xz Stream encoder
+//
+//  Copyright (C) 2009 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 "index.h"
+
+
+/// Maximum size of Index that has exactly one Record.
+/// Index Indicator + Number of Records + Record + CRC32 rounded up to
+/// the next multiple of four.
+#define INDEX_BOUND ((1 + 1 + 2 * LZMA_VLI_BYTES_MAX + 4 + 3) & ~3)
+
+/// Stream Header, Stream Footer, and Index
+#define HEADERS_BOUND (2 * LZMA_STREAM_HEADER_SIZE + INDEX_BOUND)
+
+
+extern LZMA_API size_t
+lzma_stream_buffer_bound(size_t uncompressed_size)
+{
+	// Get the maximum possible size of a Block.
+	const size_t block_bound = lzma_block_buffer_bound(uncompressed_size);
+	if (block_bound == 0)
+		return 0;
+
+	// Catch the possible integer overflow and also prevent the size of
+	// the Stream exceeding LZMA_VLI_MAX (theoretically possible on
+	// 64-bit systems).
+	if (MIN(SIZE_MAX, LZMA_VLI_MAX) - block_bound < HEADERS_BOUND)
+		return 0;
+
+	return block_bound + HEADERS_BOUND;
+}
+
+
+extern LZMA_API lzma_ret
+lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check,
+		lzma_allocator *allocator, const uint8_t *in, size_t in_size,
+		uint8_t *out, size_t *out_pos_ptr, size_t out_size)
+{
+	// Sanity checks
+	if (filters == NULL || (unsigned int)(check) > LZMA_CHECK_ID_MAX
+			|| (in == NULL && in_size != 0) || out == NULL
+			|| out_pos_ptr == NULL || *out_pos_ptr > out_size)
+		return LZMA_PROG_ERROR;
+
+	// Note for the paranoids: Index encoder prevents the Stream from
+	// getting too big and still being accepted with LZMA_OK, and Block
+	// encoder catches if the input is too big. So we don't need to
+	// separately check if the buffers are too big.
+
+	// Use a local copy. We update *out_pos_ptr only if everything
+	// succeeds.
+	size_t out_pos = *out_pos_ptr;
+
+	// Check that there's enough space for both Stream Header and
+	// Stream Footer.
+	if (out_size - out_pos <= 2 * LZMA_STREAM_HEADER_SIZE)
+		return LZMA_BUF_ERROR;
+
+	// Reserve space for Stream Footer so we don't need to check for
+	// available space again before encoding Stream Footer.
+	out_size -= LZMA_STREAM_HEADER_SIZE;
+
+	// Encode the Stream Header.
+	lzma_stream_flags stream_flags = {
+		.version = 0,
+		.check = check,
+	};
+
+	if (lzma_stream_header_encode(&stream_flags, out + out_pos)
+			!= LZMA_OK)
+		return LZMA_PROG_ERROR;
+
+	out_pos += LZMA_STREAM_HEADER_SIZE;
+
+	// Block
+	lzma_block block = {
+		.version = 0,
+		.check = check,
+		.filters = filters,
+	};
+
+	return_if_error(lzma_block_buffer_encode(&block, allocator,
+			in, in_size, out, &out_pos, out_size));
+
+	// Index
+	{
+		// Create an Index with one Record.
+		lzma_index *i = lzma_index_init(NULL, NULL);
+		if (i == NULL)
+			return LZMA_MEM_ERROR;
+
+		lzma_ret ret = lzma_index_append(i, NULL,
+				lzma_block_unpadded_size(&block),
+				block.uncompressed_size);
+
+		// If adding the Record was successful, encode the Index
+		// and get its size which will be stored into Stream Footer.
+		if (ret == LZMA_OK) {
+			ret = lzma_index_buffer_encode(
+					i, out, &out_pos, out_size);
+
+			stream_flags.backward_size = lzma_index_size(i);
+		}
+
+		lzma_index_end(i, NULL);
+
+		if (ret != LZMA_OK)
+			return ret;
+	}
+
+	// Stream Footer. We have already reserved space for this.
+	if (lzma_stream_footer_encode(&stream_flags, out + out_pos)
+			!= LZMA_OK)
+		return LZMA_PROG_ERROR;
+
+	out_pos += LZMA_STREAM_HEADER_SIZE;
+
+	// Everything went fine, make the new output position available
+	// to the application.
+	*out_pos_ptr = out_pos;
+	return LZMA_OK;
+}