Imported to git.

1 files changed, 197 insertions, 0 deletions

diff --git a/src/liblzma/api/lzma/subblock.h b/src/liblzma/api/lzma/subblock.h
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+/**
+ * \file        lzma/subblock.h
+ * \brief       Subblock filter
+ *
+ * \author      Copyright (C) 1999-2006 Igor Pavlov
+ * \author      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.
+ */
+
+#ifndef LZMA_H_INTERNAL
+#	error Never include this file directly. Use <lzma.h> instead.
+#endif
+
+
+/**
+ * \brief       Filter ID
+ *
+ * Filter ID of the Subblock filter. This is used as lzma_options_filter.id.
+ */
+#define LZMA_FILTER_SUBBLOCK    LZMA_VLI_C(0x01)
+
+
+/**
+ * \brief       Subfilter mode
+ *
+ * See lzma_options_subblock.subfilter_mode for details.
+ */
+typedef enum {
+	LZMA_SUBFILTER_NONE,
+		/**<
+		 * No Subfilter is in use.
+		 */
+
+	LZMA_SUBFILTER_SET,
+		/**<
+		 * New Subfilter has been requested to be initialized.
+		 */
+
+	LZMA_SUBFILTER_RUN,
+		/**<
+		 * Subfilter is active.
+		 */
+
+	LZMA_SUBFILTER_FINISH
+		/**<
+		 * Subfilter has been requested to be finished.
+		 */
+} lzma_subfilter_mode;
+
+
+/**
+ * \brief       Options for the Subblock filter
+ *
+ * Specifying options for the Subblock filter is optional: if the pointer
+ * options is NULL, no subfilters are allowed and the default value is used
+ * for subblock_data_size.
+ */
+typedef struct {
+	/* Options for encoder and decoder */
+
+	/**
+	 * \brief       Allowing subfilters
+	 *
+	 * If this true, subfilters are allowed.
+	 *
+	 * In the encoder, if this is set to false, subfilter_mode and
+	 * subfilter_options are completely ignored.
+	 */
+	lzma_bool allow_subfilters;
+
+	/* Options for encoder only */
+
+	/**
+	 * \brief       Alignment
+	 *
+	 * The Subblock filter encapsulates the input data into Subblocks.
+	 * Each Subblock has a header which takes a few bytes of space.
+	 * When the output of the Subblock encoder is fed to another filter
+	 * that takes advantage of the alignment of the input data (e.g. LZMA),
+	 * the Subblock filter can add padding to keep the actual data parts
+	 * in the Subblocks aligned correctly.
+	 *
+	 * The alignment should be a positive integer. Subblock filter will
+	 * add enough padding between Subblocks so that this is true for
+	 * every payload byte:
+	 * input_offset % alignment == output_offset % alignment
+	 *
+	 * The Subblock filter assumes that the first output byte will be
+	 * written to a position in the output stream that is properly aligned.
+	 *
+	 * FIXME desc
+	 */
+	uint32_t alignment;
+#	define LZMA_SUBBLOCK_ALIGNMENT_MIN 1
+#	define LZMA_SUBBLOCK_ALIGNMENT_MAX 32
+#	define LZMA_SUBBLOCK_ALIGNMENT_DEFAULT 4
+
+	/**
+	 * \brief       Size of the Subblock Data part of each Subblock
+	 *
+	 * This value is re-read every time a new Subblock is started.
+	 *
+	 * Bigger values
+	 *   - save a few bytes of space;
+	 *   - increase latency in the encoder (but no effect for decoding);
+	 *   - decrease memory locality (increased cache pollution) in the
+	 *     encoder (no effect in decoding).
+	 */
+	uint32_t subblock_data_size;
+#	define LZMA_SUBBLOCK_DATA_SIZE_MIN 1
+#	define LZMA_SUBBLOCK_DATA_SIZE_MAX (UINT32_C(1) << 28)
+#	define LZMA_SUBBLOCK_DATA_SIZE_DEFAULT 4096
+
+	/**
+	 * \brief       Run-length encoder remote control
+	 *
+	 * The Subblock filter has an internal run-length encoder (RLE). It
+	 * can be useful when the data includes byte sequences that repeat
+	 * very many times. The RLE can be used also when a Subfilter is
+	 * in use; the RLE will be applied to the output of the Subfilter.
+	 *
+	 * Note that in contrast to traditional RLE, this RLE is intended to
+	 * be used only when there's a lot of data to be repeated. If the
+	 * input data has e.g. 500 bytes of NULs now and then, this RLE
+	 * is probably useless, because plain LZMA should provide better
+	 * results.
+	 *
+	 * Due to above reasons, it was decided to keep the implementation
+	 * of the RLE very simple. When the rle variable is non-zero, it
+	 * subblock_data_size must be a multiple of rle. Once the Subblock
+	 * encoder has got subblock_data_size bytes of input, it will check
+	 * if the whole buffer of the last subblock_data_size can be
+	 * represented with repeats of chunks having size of rle bytes.
+	 *
+	 * If there are consecutive identical buffers of subblock_data_size
+	 * bytes, they will be encoded using a single repeat entry if
+	 * possible.
+	 *
+	 * If need arises, more advanced RLE can be implemented later
+	 * without breaking API or ABI.
+	 */
+	uint32_t rle;
+#	define LZMA_SUBBLOCK_RLE_OFF 0
+#	define LZMA_SUBBLOCK_RLE_MIN 1
+#	define LZMA_SUBBLOCK_RLE_MAX 256
+
+	/**
+	 * \brief       Subfilter remote control
+	 *
+	 * When the Subblock filter is initialized, this variable must be
+	 * LZMA_SUBFILTER_NONE or LZMA_SUBFILTER_SET.
+	 *
+	 * When subfilter_mode is LZMA_SUBFILTER_NONE, the application may
+	 * put Subfilter options to subfilter_options structure, and then
+	 * set subfilter_mode to LZMA_SUBFILTER_SET. This implies setting
+	 * flush to true. No new input data will be read until the Subfilter
+	 * has been enabled. Once the Subfilter has been enabled, liblzma
+	 * will set subfilter_mode to LZMA_SUBFILTER_RUN.
+	 *
+	 * When subfilter_mode is LZMA_SUBFILTER_RUN, the application may
+	 * set subfilter_mode to LZMA_SUBFILTER_FINISH. No new input data
+	 * will be read until the Subfilter has been finished. Once the
+	 * Subfilter has been finished, liblzma will set subfilter_mode
+	 * to LZMA_SUBFILTER_NONE.
+	 *
+	 * If the intent is to have Subfilter enabled to the very end of
+	 * the data, it is not needed to separately disable Subfilter with
+	 * LZMA_SUBFILTER_FINISH. Using LZMA_FINISH as the second argument
+	 * of lzma_code() will make the Subblock encoder to disable the
+	 * Subfilter once all the data has been ran through the Subfilter.
+	 *
+	 * \note        This variable is ignored if allow_subfilters is false.
+	 */
+	lzma_subfilter_mode subfilter_mode;
+
+	/**
+	 * \brief       Subfilter and its options
+	 *
+	 * When no Subfilter is used, the data is copied as is into Subblocks.
+	 * Setting a Subfilter allows encoding some parts of the data with
+	 * an additional filter. It is possible to many different Subfilters
+	 * in the same Block, although only one can be used at once.
+	 *
+	 * \note        This variable is ignored if allow_subfilters is false.
+	 */
+	lzma_options_filter subfilter_options;
+
+} lzma_options_subblock;