aboutsummaryrefslogtreecommitdiff
path: root/src/liblzma/api/lzma/stream.h
diff options
context:
space:
mode:
authorLasse Collin <lasse.collin@tukaani.org>2007-12-09 00:42:33 +0200
committerLasse Collin <lasse.collin@tukaani.org>2007-12-09 00:42:33 +0200
commit5d018dc03549c1ee4958364712fb0c94e1bf2741 (patch)
tree1b211911fb33fddb3f04b77f99e81df23623ffc4 /src/liblzma/api/lzma/stream.h
downloadxz-5d018dc03549c1ee4958364712fb0c94e1bf2741.tar.xz
Imported to git.
Diffstat (limited to 'src/liblzma/api/lzma/stream.h')
-rw-r--r--src/liblzma/api/lzma/stream.h178
1 files changed, 178 insertions, 0 deletions
diff --git a/src/liblzma/api/lzma/stream.h b/src/liblzma/api/lzma/stream.h
new file mode 100644
index 00000000..be86075f
--- /dev/null
+++ b/src/liblzma/api/lzma/stream.h
@@ -0,0 +1,178 @@
+/**
+ * \file lzma/stream.h
+ * \brief .lzma Stream handling
+ *
+ * \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 Options for .lzma Stream encoder
+ */
+typedef struct {
+ /**
+ * \brief Type of integrity Check
+ *
+ * The type of the integrity Check is stored into Stream Header
+ * and Stream Footer. The same Check is used for all Blocks in
+ * the Stream.
+ */
+ lzma_check_type check;
+
+ /**
+ * \brief Precense of CRC32 of the Block Header
+ *
+ * Set this to true if CRC32 of every Block Header should be
+ * calculated and stored in the Block Header. This is recommended.
+ *
+ * This setting is stored into Stream Header and Stream Footer.
+ */
+ lzma_bool has_crc32;
+
+ /**
+ * \brief Uncompressed Size in bytes
+ *
+ * This is somewhat advanced feature. Most users want to set this to
+ * LZMA_VLI_VALUE_UNKNOWN to indicate unknown Uncompressed Size.
+ *
+ * If the Uncompressed Size of the Stream being encoded is known,
+ * it can be stored to the beginning of the Stream. The details
+ * differ for Single-Block and Multi-Block Streams:
+ * - With Single-Block Streams, the Uncompressed Size is stored to
+ * the Block Header and End of Payload Marker is omitted.
+ * - With Multi-Block Streams, the Uncompressed Size is stored to
+ * the Header Metadata Block. The Uncompressed Size of the Blocks
+ * will be unknown, because liblzma cannot predict how the
+ * application is going to split the data in Blocks.
+ */
+ lzma_vli uncompressed_size;
+
+ /**
+ * \brief Alignment of the beginning of the Stream
+ *
+ * Certain filters handle data in bigger chunks than single bytes.
+ * This affects two things:
+ * - Performance: aligned memory access is usually faster.
+ * - Further compression ratio in custom file formats: if you
+ * encode multiple Blocks with some non-compression filter
+ * such as LZMA_FILTER_POWERPC, it is a good idea to keep
+ * the inter-Block alignment correct to maximize compression
+ * ratio when all these Blocks are finally compressed as a
+ * single step.
+ *
+ * Usually the Stream is stored into its own file, thus
+ * the alignment is usually zero.
+ */
+ uint32_t alignment;
+
+ /**
+ * \brief Array of filters used to encode Data Blocks
+ *
+ * There can be at maximum of seven filters. The end of the array is
+ * marked with .id = LZMA_VLI_VALUE_UNKNOWN. (That's why the array
+ * has eight members.) Minimum number of filters is zero; in that
+ * case, an implicit Copy filter is used.
+ */
+ lzma_options_filter filters[8];
+
+ /**
+ * \brief Array of filters used to encode Metadata Blocks
+ *
+ * This is like filters[] but for Metadata Blocks. If Metadata
+ * Blocks are compressed, they usually are compressed with
+ * settings that require only little memory to uncompress e.g.
+ * LZMA with 64 KiB dictionary.
+ *
+ * \todo Recommend a preset.
+ *
+ * When liblzma sees that the Metadata Block would be very small
+ * even in uncompressed form, it is not compressed no matter
+ * what filter have been set here. This is to avoid possibly
+ * increasing the size of the Metadata Block with bad compression,
+ * and to avoid useless overhead of filters in uncompression phase.
+ */
+ lzma_options_filter metadata_filters[8];
+
+ /**
+ * \brief Extra information in the Header Metadata Block
+ */
+ lzma_extra *header;
+
+ /**
+ * \brief Extra information in the Footer Metadata Block
+ *
+ * It is enough to set this pointer any time before calling
+ * lzma_code() with LZMA_FINISH as the second argument.
+ */
+ lzma_extra *footer;
+
+} lzma_options_stream;
+
+
+/**
+ * \brief Initializes Single-Block .lzma Stream encoder
+ *
+ * This is the function that most developers are looking for. :-) It
+ * compresses using the specified options without storing any extra
+ * information.
+ *
+ * \todo Describe that is_metadata is ignored, maybe something else.
+ */
+extern lzma_ret lzma_stream_encoder_single(
+ lzma_stream *strm, const lzma_options_stream *options);
+
+
+/**
+ * \brief Initializes Multi-Block .lzma Stream encoder
+ *
+ */
+extern lzma_ret lzma_stream_encoder_multi(
+ lzma_stream *strm, const lzma_options_stream *options);
+
+
+/**
+ * \brief Initializes decoder for .lzma Stream
+ *
+ * \param strm Pointer to propertily prepared lzma_stream
+ * \param header Pointer to hold a pointer to Extra Records read
+ * from the Header Metadata Block. Use NULL if
+ * you don't care about Extra Records.
+ * \param footer Same as header, but for Footer Metadata Block.
+ *
+ * \return - LZMA_OK: Initialization was successful.
+ * - LZMA_MEM_ERROR: Cannot allocate memory.
+ *
+ * If header and/or footer are not NULL, *header and/or *footer will be
+ * initially set to NULL.
+ *
+ * The application can detect that Header Metadata Block has been completely
+ * parsed when the decoder procudes some output the first time. If *header
+ * is still NULL, there was no Extra field in the Header Metadata Block (or
+ * the whole Header Metadata Block wasn't present at all).
+ *
+ * The application can detect that Footer Metadata Block has been parsed
+ * completely when lzma_code() returns LZMA_STREAM_END. If *footer is still
+ * NULL, there was no Extra field in the Footer Metadata Block.
+ *
+ * \note If you use lzma_memory_limitter, the Extra Records will be
+ * allocated with it, and thus remain in the lzma_memory_limitter
+ * even after they get exported to the application via *header
+ * and *footer pointers.
+ */
+extern lzma_ret lzma_stream_decoder(lzma_stream *strm,
+ lzma_extra **header, lzma_extra **footer);