Remove docs that are too outdated to be updated

(rewrite will be better).

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diff --git a/doc/liblzma-advanced.txt b/doc/liblzma-advanced.txt
deleted file mode 100644
index 6e1c9834..00000000
--- a/doc/liblzma-advanced.txt
+++ /dev/null
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-
-Advanced features of liblzma
-----------------------------
-
-0. Introduction
-
-    Most developers need only the basic features of liblzma. These
-    features allow single-threaded encoding and decoding of .lzma files
-    in streamed mode.
-
-    In some cases developers want more. The .lzma file format is
-    designed to allow multi-threaded encoding and decoding and limited
-    random-access reading. These features are possible in non-streamed
-    mode and limitedly also in streamed mode.
-
-    To take advange of these features, the application needs a custom
-    .lzma file format handler. liblzma provides a set of tools to ease
-    this task, but it's still quite a bit of work to get a good custom
-    .lzma handler done.
-
-
-1. Where to begin
-
-    Start by reading the .lzma file format specification. Understanding
-    the basics of the .lzma file structure is required to implement a
-    custom .lzma file handler and to understand the rest of this document.
-
-
-2. The basic components
-
-2.1. Stream Header and tail
-
-    Stream Header begins the .lzma Stream and Stream tail ends it. Stream
-    Header is defined in the file format specification, but Stream tail
-    isn't (thus I write "tail" with a lower-case letter). Stream tail is
-    simply the Stream Flags and the Footer Magic Bytes fields together.
-    It was done this way in liblzma, because the Block coders take care
-    of the rest of the stuff in the Stream Footer.
-
-    For now, the size of Stream Header is fixed to 11 bytes. The header
-    <lzma/stream_flags.h> defines LZMA_STREAM_HEADER_SIZE, which you
-    should use instead of a hardcoded number. Similarly, Stream tail
-    is fixed to 3 bytes, and there is a constant LZMA_STREAM_TAIL_SIZE.
-
-    It is possible, that a future version of the .lzma format will have
-    variable-sized Stream Header and tail. As of writing, this seems so
-    unlikely though, that it was considered simplest to just use a
-    constant instead of providing a functions to get and store the sizes
-    of the Stream Header and tail.
-
-
-2.x. Stream tail
-
-    For now, the size of Stream tail is fixed to 3 bytes. The header
-    <lzma/stream_flags.h> defines LZMA_STREAM_TAIL_SIZE, which you
-    should use instead of a hardcoded number.
-
-
-3. Keeping track of size information
-
-    The lzma_info_* functions found from <lzma/info.h> should ease the
-    task of keeping track of sizes of the Blocks and also the Stream
-    as a whole. Using these functions is strongly recommended, because
-    there are surprisingly many situations where an error can occur,
-    and these functions check for possible errors every time some new
-    information becomes available.
-
-    If you find lzma_info_* functions lacking something that you would
-    find useful, please contact the author.
-
-
-3.1. Start offset of the Stream
-
-    If you are storing the .lzma Stream inside anothe file format, or
-    for some other reason are placing the .lzma Stream to somewhere
-    else than to the beginning of the file, you should tell the starting
-    offset of the Stream using lzma_info_start_offset_set().
-
-    The start offset of the Stream is used for two distinct purporses.
-    First, knowing the start offset of the Stream allows
-    lzma_info_alignment_get() to correctly calculate the alignment of
-    every Block. This information is given to the Block encoder, which
-    will calculate the size of Header Padding so that Compressed Data
-    is alignment at an optimal offset.
-
-    Another use for start offset of the Stream is in random-access
-    reading. If you set the start offset of the Stream, lzma_info_locate()
-    will be able to calculate the offset relative to the beginning of the
-    file containing the Stream (instead of offset relative to the
-    beginning of the Stream).
-
-
-3.2. Size of Stream Header
-
-    While the size of Stream Header is constant (11 bytes) in the current
-    version of the .lzma file format, this may change in future.
-
-
-3.3. Size of Header Metadata Block
-
-    This information is needed when doing random-access reading, and
-    to verify the value of this field stored in Footer Metadata Block.
-
-
-3.4. Total Size of the Data Blocks
-
-
-3.5. Uncompressed Size of Data Blocks
-
-
-3.6. Index
-
-
-
-
-x. Alignment
-
-    There are a few slightly different types of alignment issues when
-    working with .lzma files.
-
-    The .lzma format doesn't strictly require any kind of alignment.
-    However, if the encoder carefully optimizes the alignment in all
-    situations, it can improve compression ratio, speed of the encoder
-    and decoder, and slightly help if the files get damaged and need
-    recovery.
-
-    Alignment has the most significant effect compression ratio FIXME
-
-
-x.1. Compression ratio
-
-    Some filters take advantage of the alignment of the input data.
-    To get the best compression ratio, make sure that you feed these
-    filters correctly aligned data.
-
-    Some filters (e.g. LZMA) don't necessarily mind too much if the
-    input doesn't match the preferred alignment. With these filters
-    the penalty in compression ratio depends on the specific type of
-    data being compressed.
-
-    Other filters (e.g. PowerPC executable filter) won't work at all
-    with data that is improperly aligned. While the data can still
-    be de-filtered back to its original form, the benefit of the
-    filtering (better compression ratio) is completely lost, because
-    these filters expect certain patterns at properly aligned offsets.
-    The compression ratio may even worse with incorrectly aligned input
-    than without the filter.
-
-
-x.1.1. Inter-filter alignment
-
-    When there are multiple filters chained, checking the alignment can
-    be useful not only with the input of the first filter and output of
-    the last filter, but also between the filters.
-
-    Inter-filter alignment important especially with the Subblock filter.
-
-
-x.1.2. Further compression with external tools
-
-    This is relatively rare situation in practice, but still worth
-    understanding.
-
-    Let's say that there are several SPARC executables, which are each
-    filtered to separate .lzma files using only the SPARC filter. If
-    Uncompressed Size is written to the Block Header, the size of Block
-    Header may vary between the .lzma files. If no Padding is used in
-    the Block Header to correct the alignment, the starting offset of
-    the Compressed Data field will be differently aligned in different
-    .lzma files.
-
-    All these .lzma files are archived into a single .tar archive. Due
-    to nature of the .tar format, every file is aligned inside the
-    archive to an offset that is a multiple of 512 bytes.
-
-    The .tar archive is compressed into a new .lzma file using the LZMA
-    filter with options, that prefer input alignment of four bytes. Now
-    if the independent .lzma files don't have the same alignment of
-    the Compressed Data fields, the LZMA filter will be unable to take
-    advantage of the input alignment between the files in the .tar
-    archive, which reduces compression ratio.
-
-    Thus, even if you have only single Block per file, it can be good for
-    compression ratio to align the Compressed Data to optimal offset.
-
-
-x.2. Speed
-
-    Most modern computers are faster when multi-byte data is located
-    at aligned offsets in RAM. Proper alignment of the Compressed Data
-    fields can slightly increase the speed of some filters.
-
-
-x.3. Recovery
-
-    Aligning every Block Header to start at an offset with big enough
-    alignment may ease or at least speed up recovery of broken files.
-
-
-y. Typical usage cases
-
-y.x. Parsing the Stream backwards
-
-    You may need to parse the Stream backwards if you need to get
-    information such as the sizes of the Stream, Index, or Extra.
-    The basic procedure to do this follows.
-
-    Locate the end of the Stream. If the Stream is stored as is in a
-    standalone .lzma file, simply seek to the end of the file and start
-    reading backwards using appropriate buffer size. The file format
-    specification allows arbitrary amount of Footer Padding (zero or more
-    NUL bytes), which you skip before trying to decode the Stream tail.
-
-    Once you have located the end of the Stream (a non-NULL byte), make
-    sure you have at least the last LZMA_STREAM_TAIL_SIZE bytes of the
-    Stream in a buffer. If there isn't enough bytes left from the file,
-    the file is too small to contain a valid Stream. Decode the Stream
-    tail using lzma_stream_tail_decoder(). Store the offset of the first
-    byte of the Stream tail; you will need it later.
-
-    You may now want to do some internal verifications e.g. if the Check
-    type is supported by the liblzma build you are using.
-
-    Decode the Backward Size field with lzma_vli_reverse_decode(). The
-    field is at maximum of LZMA_VLI_BYTES_MAX bytes long. Check that
-    Backward Size is not zero. Store the offset of the first byte of
-    the Backward Size; you will need it later.
-
-    Now you know the Total Size of the last Block of the Stream. It's the
-    value of Backward Size plus the size of the Backward Size field. Note
-    that you cannot use lzma_vli_size() to calculate the size since there
-    might be padding; you need to use the real observed size of the
-    Backward Size field.
-
-    At this point, the operation continues differently for Single-Block
-    and Multi-Block Streams.
-
-
-y.x.1. Single-Block Stream
-
-    There might be Uncompressed Size field present in the Stream Footer.
-    You cannot know it for sure unless you have already parsed the Block
-    Header earlier. For security reasons, you probably want to try to
-    decode the Uncompressed Size field, but you must not indicate any
-    error if decoding fails. Later you can give the decoded Uncompressed
-    Size to Block decoder if Uncopmressed Size isn't otherwise known;
-    this prevents it from producing too much output in case of (possibly
-    intentionally) corrupt file.
-
-    Calculate the start offset of the Stream:
-
-        backward_offset - backward_size - LZMA_STREAM_HEADER_SIZE
-
-    backward_offset is the offset of the first byte of the Backward Size
-    field. Remember to check for integer overflows, which can occur with
-    invalid input files.
-
-    Seek to the beginning of the Stream. Decode the Stream Header using
-    lzma_stream_header_decoder(). Verify that the decoded Stream Flags
-    match the values found from Stream tail. You can use the
-    lzma_stream_flags_is_equal() macro for this.
-
-    Decode the Block Header. Verify that it isn't a Metadata Block, since
-    Single-Block Streams cannot have Metadata. If Uncompressed Size is
-    present in the Block Header, the value you tried to decode from the
-    Stream Footer must be ignored, since Uncompressed Size wasn't actually
-    present there. If Block Header doesn't have Uncompressed Size, and
-    decoding the Uncompressed Size field from the Stream Footer failed,
-    the file is corrupt.
-
-    If you were only looking for the Uncompressed Size of the Stream,
-    you now got that information, and you can stop processing the Stream.
-
-    To decode the Block, the same instructions apply as described in
-    FIXME. However, because you have some extra known information decoded
-    from the Stream Footer, you should give this information to the Block
-    decoder so that it can verify it while decoding:
-      - If Uncompressed Size is not present in the Block Header, set
-        lzma_options_block.uncompressed_size to the value you decoded
-        from the Stream Footer.
-      - Always set lzma_options_block.total_size to backward_size +
-        size_of_backward_size (you calculated this sum earlier already).
-
-
-y.x.2. Multi-Block Stream
-
-    Calculate the start offset of the Footer Metadata Block:
-
-        backward_offset - backward_size
-
-    backward_offset is the offset of the first byte of the Backward Size
-    field. Remember to check for integer overflows, which can occur with
-    broken input files.
-
-    Decode the Block Header. Verify that it is a Metadata Block. Set
-    lzma_options_block.total_size to backward_size + size_of_backward_size
-    (you calculated this sum earlier already). Then decode the Footer
-    Metadata Block.
-
-    Store the decoded Footer Metadata to lzma_info structure using
-    lzma_info_set_metadata(). Set also the offset of the Backward Size
-    field using lzma_info_size_set(). Then you can get the start offset
-    of the Stream using lzma_info_size_get(). Note that any of these steps
-    may fail so don't omit error checking.
-
-    Seek to the beginning of the Stream. Decode the Stream Header using
-    lzma_stream_header_decoder(). Verify that the decoded Stream Flags
-    match the values found from Stream tail. You can use the
-    lzma_stream_flags_is_equal() macro for this.
-
-    If you were only looking for the Uncompressed Size of the Stream,
-    it's possible that you already have it now. If Uncompressed Size (or
-    whatever information you were looking for) isn't available yet,
-    continue by decoding also the Header Metadata Block. (If some
-    information is missing, the Header Metadata Block has to be present.)
-
-    Decoding the Data Blocks goes the same way as described in FIXME.
-
-
-y.x.3. Variations
-
-    If you know the offset of the beginning of the Stream, you may want
-    to parse the Stream Header before parsing the Stream tail.
-
diff --git a/doc/liblzma-hacking.txt b/doc/liblzma-hacking.txt
deleted file mode 100644
index 64390bcb..00000000
--- a/doc/liblzma-hacking.txt
+++ /dev/null
@@ -1,112 +0,0 @@
-
-Hacking liblzma
----------------
-
-0. Preface
-
-    This document gives some overall information about the internals of
-    liblzma, which should make it easier to start reading and modifying
-    the code.
-
-
-1. Programming language
-
-    liblzma was written in C99. If you use GCC, this means that you need
-    at least GCC 3.x.x. GCC 2 isn't and won't be supported.
-
-    Some GCC-specific extensions are used *conditionally*. They aren't
-    required to build a full-featured library. Don't make the code rely
-    on any non-standard compiler extensions or even C99 features that
-    aren't portable between almost-C99 compatible compilers (for example
-    non-static inlines).
-
-    The public API headers are in C89. This is to avoid frustrating those
-    who maintain programs, which are strictly in C89 or C++.
-
-    An assumption about sizeof(size_t) is made. If this assumption is
-    wrong, some porting is probably needed:
-
-        sizeof(uint32_t) <= sizeof(size_t) <= sizeof(uint64_t)
-
-
-2. Internal vs. external API
-
-
-
-        Input                         Output
-          v     Application             ^
-          |     liblzma public API      |
-          |     Stream coder            |
-          |     Block coder             |
-          |     Filter coder            |
-          |     ...                     |
-          v     Filter coder            ^
-
-
-        Application
-          `-- liblzma public API
-                `-- Stream coder
-                      |-- Stream info handler
-                      |-- Stream Header coder
-                      |-- Block Header coder
-                      |     `-- Filter Flags coder
-                      |-- Metadata coder
-                      |     `-- Block coder
-                      |           `-- Filter 0
-                      |                 `-- Filter 1
-                      |                     ...
-                      |-- Data Block coder
-                      |     `-- Filter 0
-                      |           `-- Filter 1
-                      |               ...
-                      `-- Stream tail coder
-
-
-
-x. Designing new filters
-
-    All filters must be designed so that the decoder cannot consume
-    arbitrary amount input without producing any decoded output. Failing
-    to follow this rule makes liblzma vulnerable to DoS attacks if
-    untrusted files are decoded (usually they are untrusted).
-
-    An example should clarify the reason behind this requirement: There
-    are two filters in the chain. The decoder of the first filter produces
-    huge amount of output (many gigabytes or more) with a few bytes of
-    input, which gets passed to the decoder of the second filter. If the
-    data passed to the second filter is interpreted as something that
-    produces no output (e.g. padding), the filter chain as a whole
-    produces no output and consumes no input for a long period of time.
-
-    The above problem was present in the first versions of the Subblock
-    filter. A tiny .lzma file could have taken several years to decode
-    while it wouldn't produce any output at all. The problem was fixed
-    by adding limits for number of consecutive Padding bytes, and requiring
-    that some decoded output must be produced between Set Subfilter and
-    Unset Subfilter.
-
-
-x. Implementing new filters
-
-    If the filter supports embedding End of Payload Marker, make sure that
-    when your filter detects End of Payload Marker,
-      - the usage of End of Payload Marker is actually allowed (i.e. End
-        of Input isn't used); and
-      - it also checks that there is no more input coming from the next
-        filter in the chain.
-
-    The second requirement is slightly tricky. It's possible that the next
-    filter hasn't returned LZMA_STREAM_END yet. It may even need a few
-    bytes more input before it will do so. You need to give it as much
-    input as it needs, and verify that it doesn't produce any output.
-
-    Don't call the next filter in the chain after it has returned
-    LZMA_STREAM_END (except in encoder if action == LZMA_SYNC_FLUSH).
-    It will result undefined behavior.
-
-    Be pedantic. If the input data isn't exactly valid, reject it.
-
-    At the moment, liblzma isn't modular. You will need to edit several
-    files in src/liblzma/common to include support for a new filter. grep
-    for LZMA_FILTER_LZMA to locate the files needing changes.
-
diff --git a/doc/liblzma-intro.txt b/doc/liblzma-intro.txt
deleted file mode 100644
index 52c4d920..00000000
--- a/doc/liblzma-intro.txt
+++ /dev/null
@@ -1,194 +0,0 @@
-
-Introduction to liblzma
------------------------
-
-Writing applications to work with liblzma
-
-    liblzma API is split in several subheaders to improve readability and
-    maintainance. The subheaders must not be #included directly. lzma.h
-    requires that certain integer types and macros are available when
-    the header is #included. On systems that have inttypes.h that conforms
-    to C99, the following will work:
-
-        #include <sys/types.h>
-        #include <inttypes.h>
-        #include <lzma.h>
-
-    Those who have used zlib should find liblzma's API easy to use.
-    To developers who haven't used zlib before, I recommend learning
-    zlib first, because zlib has excellent documentation.
-
-    While the API is similar to that of zlib, there are some major
-    differences, which are summarized below.
-
-    For basic stream encoding, zlib has three functions (deflateInit(),
-    deflate(), and deflateEnd()). Similarly, there are three functions
-    for stream decoding (inflateInit(), inflate(), and inflateEnd()).
-    liblzma has only single coding and ending function. Thus, to
-    encode one may use, for example, lzma_stream_encoder_single(),
-    lzma_code(), and lzma_end(). Simlarly for decoding, one may
-    use lzma_auto_decoder(), lzma_code(), and lzma_end().
-
-    zlib has deflateReset() and inflateReset() to reset the stream
-    structure without reallocating all the memory. In liblzma, all
-    coder initialization functions are like zlib's reset functions:
-    the first-time initializations are done with the same functions
-    as the reinitializations (resetting).
-
-    To make all this work, liblzma needs to know when lzma_stream
-    doesn't already point to an allocated and initialized coder.
-    This is achieved by initializing lzma_stream structure with
-    LZMA_STREAM_INIT (static initialization) or LZMA_STREAM_INIT_VAR
-    (for exampple when new lzma_stream has been allocated with malloc()).
-    This initialization should be done exactly once per lzma_stream
-    structure to avoid leaking memory. Calling lzma_end() will leave
-    lzma_stream into a state comparable to the state achieved with
-    LZMA_STREAM_INIT and LZMA_STREAM_INIT_VAR.
-
-    Example probably clarifies a lot. With zlib, compression goes
-    roughly like this:
-
-        z_stream strm;
-        deflateInit(&strm, level);
-        deflate(&strm, Z_RUN);
-        deflate(&strm, Z_RUN);
-        ...
-        deflate(&strm, Z_FINISH);
-        deflateEnd(&strm) or deflateReset(&strm)
-
-    With liblzma, it's slightly different:
-
-        lzma_stream strm = LZMA_STREAM_INIT;
-        lzma_stream_encoder_single(&strm, &options);
-        lzma_code(&strm, LZMA_RUN);
-        lzma_code(&strm, LZMA_RUN);
-        ...
-        lzma_code(&strm, LZMA_FINISH);
-        lzma_end(&strm) or reinitialize for new coding work
-
-     Reinitialization in the last step can be any function that can
-     initialize lzma_stream; it doesn't need to be the same function
-     that was used for the previous initialization. If it is the same
-     function, liblzma will usually be able to re-use most of the
-     existing memory allocations (depends on how much the initialization
-     options change). If you reinitialize with different function,
-     liblzma will automatically free the memory of the previous coder.
-
-
-File formats
-
-    liblzma supports multiple container formats for the compressed data.
-    Different initialization functions initialize the lzma_stream to
-    process different container formats. See the details from the public
-    header files.
-
-    The following functions are the most commonly used:
-
-      - lzma_stream_encoder_single(): Encodes Single-Block Stream; this
-        the recommended format for most purporses.
-
-      - lzma_alone_encoder(): Useful if you need to encode into the
-        legacy LZMA_Alone format.
-
-      - lzma_auto_decoder(): Decoder that automatically detects the
-        file format; recommended when you decode compressed files on
-        disk, because this way compatibility with the legacy LZMA_Alone
-        format is transparent.
-
-      - lzma_stream_decoder(): Decoder for Single- and Multi-Block
-        Streams; this is good if you want to accept only .lzma Streams.
-
-
-Filters
-
-    liblzma supports multiple filters (algorithm implementations). The new
-    .lzma format supports filter-chain having up to seven filters. In the
-    filter chain, the output of one filter is input of the next filter in
-    the chain. The legacy LZMA_Alone format supports only one filter, and
-    that must always be LZMA.
-
-        General-purporse compression:
-
-            LZMA        The main algorithm of liblzma (surprise!)
-
-        Branch/Call/Jump filters for executables:
-
-            x86         This filter is known as BCJ in 7-Zip
-            IA64        IA-64 (Itanium)
-            PowerPC     Big endian PowerPC
-            ARM
-            ARM-Thumb
-            SPARC
-
-        Other filters:
-
-            Copy        Dummy filter that simply copies all the data
-                        from input to output.
-
-            Subblock    Multi-purporse filter, that can
-                          - embed End of Payload Marker if the previous
-                            filter in the chain doesn't support it; and
-                          - apply Subfilters, which filter only part
-                            of the same compressed Block in the Stream.
-
-    Branch/Call/Jump filters never change the size of the data. They
-    should usually be used as a pre-filter for some compression filter
-    like LZMA.
-
-
-Integrity checks
-
-    The .lzma Stream format uses CRC32 as the integrity check for
-    different file format headers. It is possible to omit CRC32 from
-    the Block Headers, but not from Stream Header. This is the reason
-    why CRC32 code cannot be disabled when building liblzma (in addition,
-    the LZMA encoder uses CRC32 for hashing, so that's another reason).
-
-    The integrity check of the actual data is calculated from the
-    uncompressed data. This check can be CRC32, CRC64, or SHA256.
-    It can also be omitted completely, although that usually is not
-    a good thing to do. There are free IDs left, so support for new
-    checks algorithms can be added later.
-
-
-API and ABI stability
-
-    The API and ABI of liblzma isn't stable yet, although no huge
-    changes should happen. One potential place for change is the
-    lzma_options_subblock structure.
-
-    In the 4.42.0alpha phase, the shared library version number won't
-    be updated even if ABI breaks. I don't want to track the ABI changes
-    yet. Just rebuild everything when you upgrade liblzma until we get
-    to the beta stage.
-
-
-Size of the library
-
-    While liblzma isn't huge, it is quite far from the smallest possible
-    LZMA implementation: full liblzma binary (with support for all
-    filters and other features) is way over 100 KiB, but the plain raw
-    LZMA decoder is only 5-10 KiB.
-
-    To decrease the size of the library, you can omit parts of the library
-    by passing certain options to the `configure' script. Disabling
-    everything but the decoders of the require filters will usually give
-    you a small enough library, but if you need a decoder for example
-    embedded in the operating system kernel, the code from liblzma probably
-    isn't suitable as is.
-
-    If you need a minimal implementation supporting .lzma Streams, you
-    may need to do partial rewrite. liblzma uses stateful API like zlib.
-    That increases the size of the library. Using callback API or even
-    simpler buffer-to-buffer API would allow smaller implementation.
-
-    LZMA SDK contains smaller LZMA decoder written in ANSI-C than
-    liblzma, so you may want to take a look at that code. However,
-    it doesn't (at least not yet) support the new .lzma Stream format.
-
-
-Documentation
-
-    There's no other documentation than the public headers and this
-    text yet. Real docs will be written some day, I hope.
-
diff --git a/doc/liblzma-security.txt b/doc/liblzma-security.txt
deleted file mode 100644
index 55bc57bc..00000000
--- a/doc/liblzma-security.txt
+++ /dev/null
@@ -1,219 +0,0 @@
-
-Using liblzma securely
-----------------------
-
-0. Introduction
-
-    This document discusses how to use liblzma securely. There are issues
-    that don't apply to zlib or libbzip2, so reading this document is
-    strongly recommended even for those who are very familiar with zlib
-    or libbzip2.
-
-    While making liblzma itself as secure as possible is essential, it's
-    out of scope of this document.
-
-
-1. Memory usage
-
-    The memory usage of liblzma varies a lot.
-
-
-1.1. Problem sources
-
-1.1.1. Block coder
-
-    The memory requirements of Block encoder depend on the used filters
-    and their settings. The memory requirements of the Block decoder
-    depend on the which filters and with which filter settings the Block
-    was encoded. Usually the memory requirements of a decoder are equal
-    or less than the requirements of the encoder with the same settings.
-
-    While the typical memory requirements to decode a Block is from a few
-    hundred kilobytes to tens of megabytes, a maliciously constructed
-    files can require a lot more RAM to decode. With the current filters,
-    the maximum amount is about 7 GiB. If you use multi-threaded decoding,
-    every Block can require this amount of RAM, thus a four-threaded
-    decoder could suddenly try to allocate 28 GiB of RAM.
-
-    If you don't limit the maximum memory usage in any way, and there are
-    no resource limits set on the operating system side, one malicious
-    input file can run the system out of memory, or at least make it swap
-    badly for a long time. This is exceptionally bad on servers e.g.
-    email server doing virus scanning on incoming messages.
-
-
-1.1.2. Metadata decoder
-
-    Multi-Block .lzma files contain at least one Metadata Block.
-    Externally the Metadata Blocks are similar to Data Blocks, so all
-    the issues mentioned about memory usage of Data Blocks applies to
-    Metadata Blocks too.
-
-    The uncompressed content of Metadata Blocks contain information about
-    the Stream as a whole, and optionally some Extra Records. The
-    information about the Stream is kept in liblzma's internal data
-    structures in RAM. Extra Records can contain arbitrary data. They are
-    not interpreted by liblzma, but liblzma will provide them to the
-    application in uninterpreted form if the application wishes so.
-
-    Usually the Uncompressed Size of a Metadata Block is small. Even on
-    extreme cases, it shouldn't be much bigger than a few megabytes. Once
-    the Metadata has been parsed into native data structures in liblzma,
-    it usually takes a little more memory than in the encoded form. For
-    all normal files, this is no problem, since the resulting memory usage
-    won't be too much.
-
-    The problem is that a maliciously constructed Metadata Block can
-    contain huge amount of "information", which liblzma will try to store
-    in its internal data structures. This may cause liblzma to allocate
-    all the available RAM unless some kind of resource usage limits are
-    applied.
-
-    Note that the Extra Records in Metadata are always parsed but, but
-    memory is allocated for them only if the application has requested
-    liblzma to provide the Extra Records to the application.
-
-
-1.2. Solutions
-
-    If you need to decode files from untrusted sources (most people do),
-    you must limit the memory usage to avoid denial of service (DoS)
-    conditions caused by malicious input files.
-
-    The first step is to find out how much memory you are allowed consume
-    at maximum. This may be a hardcoded constant or derived from the
-    available RAM; whatever is appropriate in the application.
-
-    The simplest solution is to use setrlimit() if the kernel supports
-    RLIMIT_AS, which limits the memory usage of the whole process.
-    For more portable and fine-grained limiting, you can use
-    memory limiter functions found from <lzma/memlimit.h>.
-
-
-1.2.1. Encoder
-
-    lzma_memory_usage() will give you a rough estimate about the memory
-    usage of the given filter chain. To dramatically simplify the internal
-    implementation, this function doesn't take into account all the small
-    helper data structures needed in various places; only the structures
-    with significant memory usage are taken into account. Still, the
-    accuracy of this function should be well within a mebibyte.
-
-    The Subblock filter is a special case. If a Subfilter has been
-    specified, it isn't taken into account when lzma_memory_usage()
-    calculates the memory usage. You need to calculate the memory usage
-    of the Subfilter separately.
-
-    Keeping track of Blocks in a Multi-Block Stream takes a few dozen
-    bytes of RAM per Block (size of the lzma_index structure plus overhead
-    of malloc()). It isn't a good idea to put tens of thousands of Blocks
-    into a Stream unless you have a very good reason to do so (compressed
-    dictionary could be an example of such situation).
-
-    Also keep the number and sizes of Extra Records sane. If you produce
-    the list of Extra Records automatically from some untrusted source,
-    you should not only validate the content of these Records, but also
-    their memory usage.
-
-
-1.2.2. Decoder
-
-    A single-threaded decoder should simply use a memory limiter and
-    indicate an error if it runs out of memory.
-
-    Memory-limiting with multi-threaded decoding is tricky. The simple
-    solution is to divide the maximum allowed memory usage with the
-    maximum allowed threads, and give each Block decoder their own
-    independent lzma_memory_limiter. The drawback is that if one Block
-    needs notably more RAM than any other Block, the decoder will run out
-    of memory when in reality there would be plenty of free RAM.
-
-    An attractive alternative would be using shared lzma_memory_limiter.
-    Depending on the application and the expected type of input, this may
-    either be the best solution or a source of hard-to-repeat problems.
-    Consider the following requirements:
-      - You use a maximum of n threads.
-      - x(i) is the decoder memory requirements of the Block number i
-        in an expected input Stream.
-      - The memory limiter is set to higher value than the sum of n
-        highest values x(i).
-
-    (If you are better at explaining the above conditions, please
-    contribute your improved version.)
-
-    If the above conditions aren't met, it is possible that the decoding
-    will fail unpredictably. That is, on the same machine using the same
-    settings, the decoding may sometimes succeed and sometimes fail. This
-    is because sometimes threads may run so that the Blocks with highest
-    memory usage are tried to be decoded at the same time.
-
-    Most .lzma files have all the Blocks encoded with identical settings,
-    or at least the memory usage won't vary dramatically. That's why most
-    multi-threaded decoders probably want to use the simple "separate
-    lzma_memory_limiter for each thread" solution, possibly falling back
-    to single-threaded mode in case the per-thread memory limits aren't
-    enough in multi-threaded mode.
-
-FIXME: Memory usage of Stream info.
-
-[
-
-]
-
-
-2. Huge uncompressed output
-
-2.1. Data Blocks
-
-    Decoding a tiny .lzma file can produce huge amount of uncompressed
-    output. There is an example file of 45 bytes, which decodes to 64 PiB
-    (that's 2^56 bytes). Uncompressing such a file to disk is likely to
-    fill even a bigger disk array. If the data is written to a pipe, it
-    may not fill the disk, but would still take very long time to finish.
-
-    To avoid denial of service conditions caused by huge amount of
-    uncompressed output, applications using liblzma should use some method
-    to limit the amount of output produced. The exact method depends on
-    the application.
-
-    All valid .lzma Streams make it possible to find out the uncompressed
-    size of the Stream without actually uncompressing the data. This
-    information is available in at least one of the Metadata Blocks.
-    Once the uncompressed size is parsed, the decoder can verify that
-    it doesn't exceed certain limits (e.g. available disk space).
-
-    When the uncompressed size is known, the decoder can actively keep
-    track of the amount of output produced so far, and that it doesn't
-    exceed the known uncompressed size. If it does exceed, the file is
-    known to be corrupt and an error should be indicated without
-    continuing to decode the rest of the file.
-
-    Unfortunately, finding the uncompressed size beforehand is often
-    possible only in non-streamed mode, because the needed information
-    could be in the Footer Metdata Block, which (obviously) is at the
-    end of the Stream. In purely streamed mode decoding, one may need to
-    use some rough arbitrary limits to prevent the problems described in
-    the beginning of this section.
-
-
-2.2. Metadata
-
-    Metadata is stored in Metadata Blocks, which are very similar to
-    Data Blocks. Thus, the uncompressed size can be huge just like with
-    Data Blocks. The difference is, that the contents of Metadata Blocks
-    aren't given to the application as is, but parsed by liblzma. Still,
-    reading through a huge Metadata can take very long time, effectively
-    creating a denial of service like piping decoded a Data Block to
-    another process would do.
-
-    At first it would seem that using a memory limiter would prevent
-    this issue as a side effect. But it does so only if the application
-    requests liblzma to allocate the Extra Records and provide them to
-    the application. If Extra Records aren't requested, they aren't
-    allocated either. Still, the Extra Records are being read through
-    to validate that the Metadata is in proper format.
-
-    The solution is to limit the Uncompressed Size of a Metadata Block
-    to some relatively large value. This will make liblzma to give an
-    error when the given limit is reached.
-
diff --git a/doc/lzma-intro.txt b/doc/lzma-intro.txt
deleted file mode 100644
index bde8a059..00000000
--- a/doc/lzma-intro.txt
+++ /dev/null
@@ -1,107 +0,0 @@
-
-Introduction to the lzma command line tool
-------------------------------------------
-
-Overview
-
-    The lzma command line tool is similar to gzip and bzip2, but for
-    compressing and uncompressing .lzma files.
-
-
-Supported file formats
-
-    By default, the tool creates files in the new .lzma format. This can
-    be overriden with --format=FMT command line option. Use --format=alone
-    to create files in the old LZMA_Alone format.
-
-    By default, the tool uncompresses both the new .lzma format and
-    LZMA_Alone format. This is to make it transparent to switch from
-    the old LZMA_Alone format to the new .lzma format. Since both
-    formats use the same filename suffix, average user should never
-    notice which format was used.
-
-
-Differences to gzip and bzip2
-
-  Standard input and output
-
-    Both gzip and bzip2 refuse to write compressed data to a terminal and
-    read compressed data from a terminal. With gzip (but not with bzip2),
-    this can be overriden with the `--force' option. lzma follows the
-    behavior of gzip here.
-
-  Usage of LZMA_OPT environment variable
-
-    gzip and bzip2 read GZIP and BZIP2 environment variables at startup.
-    These variables may contain extra command line options.
-
-    gzip and bzip2 allow passing not only options, but also end-of-options
-    indicator (`--') and filenames via the environment variable. No quoting
-    is supported with the filenames.
-
-    Here are examples with gzip. bzip2 behaves identically.
-
-        bash$ echo asdf > 'foo bar'
-        bash$ GZIP='"foo bar"' gzip
-        gzip: "foo: No such file or directory
-        gzip: bar": No such file or directory
-
-        bash$ GZIP=-- gzip --help
-        gzip: --help: No such file or directory
-
-    lzma silently ignores all non-option arguments given via the
-    environment variable LZMA_OPT. Like on the command line, everything
-    after `--' is taken as non-options, and thus ignored in LZMA_OPT.
-
-        bash$ LZMA_OPT='--help' lzma --version     # Displays help
-        bash$ LZMA_OPT='-- --help' lzma --version  # Displays version
-
-
-Filter chain presets
-
-    Like in gzip and bzip2, lzma supports numbered presets from 1 to 9
-    where 1 is the fastest and 9 the best compression. 1 and 2 are for
-    fast compressing with small memory usage, 3 to 6 for good compression
-    ratio with medium memory usage, and 7 to 9 for excellent compression
-    ratio with higher memory requirements. The default is 7 if memory
-    usage limit allows.
-
-    In future, there will probably be an option like --preset=NAME, which
-    will contain more special presets for specific file types.
-
-    It's also possible that there will be some heuristics to select good
-    filters. For example, the tool could detect when a .tar archive is
-    being compressed, and enable x86 filter only for those files in the
-    .tar archive that are ELF or PE executables for x86.
-
-
-Specifying custom filter chains
-
-    Custom filter chains are specified by using long options with the name
-    of the filters in correct order. For example, to pass the input data to
-    the x86 filter and the output of that to the LZMA filter, the following
-    command will do:
-
-        lzma --x86 --lzma filename
-
-    Some filters accept options, which are specified as a comma-separated
-    list of key=value pairs:
-
-        lzma --delta=distance=4 --lzma=dict=4Mi,lc=8,lp=2 filename
-
-
-Memory usage control
-
-    By default, the command line tool limits memory usage to 1/3 of the
-    available physical RAM. If no preset or custom filter chain has been
-    given, the default preset will be used. If the memory limit is too
-    low for the default preset, the tool will silently switch to lower
-    preset.
-
-    When a preset or a custom filter chain has been specified and the
-    memory limit is too low, an error message is displayed and no files
-    are processed.
-
-    If the decoder hits the memory usage limit, an error is displayed and
-    no more files are processed.
-