Attachment #847995 for bug #884185




# TinyDeflate

See https://github.com/bisqwit/TinyDeflate for the original version.

A deflate/gzip decompressor, as a C++17 template function,
that requires minimal amount of memory to work.

    Terms of use: Zlib    
    Copyright © 2018 Joel Yliluoma

## Memory usage at aggressive settings (backtrackable input)

* 408 bytes of automatic storage for three huffman trees (384 elements, 5…9 bits each, 88 % space efficiency)
* 24 bytes of temporary automatic storage while a huffman tree is being generated (15 elements, 9 bits each, 66 % space efficiency)
* An assortment of automatic variables for various purposes (may be register variables, depending on the architecture and of the compiler wits)
* ABI mandated alignment losses

Total: 408 bytes minimum, 432+N bytes maximum

Theoretical minimum at 100 % efficiency: 357.1 + 15.32 ≃ 373 bytes (not yet attained by this library).

## Memory usage at aggressive settings (non-backtrackable input)

* 144 bytes of automatic storage for length tables (288 elements, 4 bits each, 100 % space efficiency)
* 384 bytes of automatic storage for two huffman trees (350 elements, 5…9 bits each, 88 % space efficiency)
* 24 bytes of temporary automatic storage while a huffman tree is being generated (15 elements, 9 bits each, 66 % space efficiency)
* An assortment of automatic variables for various purposes (may be register variables, depending on the architecture and of the compiler wits)
* ABI mandated alignment losses

Total: 528 bytes minimum, 552+N bytes maximum

Theoretical minimum at 100 % efficiency: 144 + 338.9 + 15.32 ≃ 499 bytes (not yet attained by this library).

## Memory usage at default settings (backtrackable input)

* 687 bytes of automatic storage for three huffman trees (52 % space efficiency)
* 30 bytes of temporary automatic storage while a huffman tree is being generated (53 % space efficiency)
* An assortment of automatic variables for various purposes (may be register variables, depending on the architecture and of the compiler wits)
* ABI mandated alignment losses

Total: 687 bytes minimum, 717+N bytes maximum

## Memory usage at default settings (non-backtrackable input)

* 288 bytes of automatic storage for length tables (50 % space efficiency)
* 653 bytes of automatic storage for two huffman trees (52 % space efficiency)
* 30 bytes of temporary automatic storage while a huffman tree is being generated (53 % space efficiency)
* An assortment of automatic variables for various purposes (may be register variables, depending on the architecture and of the compiler wits)
* ABI mandated alignment losses

Total: 941 bytes minimum, 971+N bytes maximum

## Tuning

To adjust the memory usage, there are three settings in gunzip.hh you can change:

| Setting name | 'false' memory use bytes | 'true' memory use bytes | 'true' performance impact
| ------------------------------------------- | ---:| ----:|--------------
| `USE_BITARRAY_TEMPORARY_IN_HUFFMAN_CREATION` |     30     |     24     | Negligible
| `USE_BITARRAY_FOR_LENGTHS`                   | 288 or   0 | 144 or   0 | Noticeable
| `USE_BITARRAY_FOR_HUFFNODES`                 | 653 or 687 | 384 or 408 | Significant
| **Total**                                    | 971 or 717 | 552 or 432 | _Plus alignment losses, callframes and spills_

In addition, if you neither decompress into a raw memory area nor supply your own window function,
32768 bytes of automatic storage is allocated for the look-behind window.

You can also change the memory allocation scheme:

| `#define` name | Meaning
| --- | ---
| `DEFLATE_ALLOCATION_AUTOMATIC` | Automatic allocation (usually stack)
| `DEFLATE_ALLOCATION_STATIC`    | Static `thread_local` allocation (memory remains allocated throughout the program, and different threads have their own copy of the data). Note that this scheme excludes running multiple decompressions in parallel, unless you do it in different threads.
| `DEFLATE_ALLOCATION_DYNAMIC`   | Storage duration is the same as with automatic allocation, but the `new` keyword is explicitly used (which usually means heap/bss allocation).

There is also a constant `MAX_WINDOW_SIZE`, which is 32768 by default,
but you can reduce it to use less memory for the automatically allocated
window in situations where one is allocated (see note 9 below).
Note that this value must not be smaller than the maximum backreference
distance used by your compressed data.

## Unrequirements

* No dynamic memory is allocated under any circumstances, unless your user-supplied functors do it, or you `#define DEFLATE_ALLOCATION_DYNAMIC`.
* Aside from assert() in assert.h and some template metaprogramming tools in type_traits, no standard library functions are used.
* No global variables.
* Compatible with -fno-exceptions -fno-rtti compilation.
* Option to compile without constant arrays.

## Rationale

* Embedded platforms (Arduino, STM32 etc).
* ROM hacking

## Caveats

* Decompressor only. Deflate and GZIP streams are supported.
* Slower than your average inflate function. The template uses densely bitpacked arrays, which require plenty of bit-shifting operations for every access.
* The code obviously performs best on 32-bit or 64-bit platforms. Platforms where 32-bit entities must be synthesized from a number of 8-bit entities are at a disadvantage.
* Decompressed data integrity is not verified. Any checksum fields are totally ignored.
* On most systems, automatic storage means ‘stack allocation’. Depending on your circumstances, you may want to change the memory allocation scheme. See the Tuning chapter for details.

## Definitions

```C++
struct DeflateTrackNoSize{};
struct DeflateTrackInSize{};
struct DeflateTrackOutSize{};
struct DeflateTrackBothSize{};

int/*exit status*/ Deflate(InputParams..., OutputParams...,  DeflateTrackNoSize = {});

std::pair<int/*exit status*/, std::uint_fast64_t/*number of input bytes consumed*/>
    Deflate(InputParams..., OutputParams...,  DeflateTrackInSize);   // (11)

std::pair<int/*exit status*/, std::uint_fast64_t/*number of output bytes generated*/>
    Deflate(InputParams..., OutputParams...,  DeflateTrackOutSize);  // (12)

std::pair<int/*exit status*/, std::pair<std::uint_fast64_t/*in size*/, std::uint_fast64_t/*out size*/>>
    Deflate(InputParams..., OutputParams...,  DeflateTrackBothSize); // (13)

// A counter for sizes is only allocated if explicitly requested
// by using one of the former three tracking overloads.
```

`InputParams` may be one of the following sets of parameters:

* InputFunctor   input                                   `(5)` `(14)`
* InputIterator  begin                                   `(7)` `(14)`
* InputIterator  begin, InputIterator end                `(6)` `(14)`
* InputIterator  begin, SizeType length                  `(8)` `(14)`
* BidirectionalIterator begin, SizeType length           `(8)` `(15)`
* ForwardIterator       begin                            `(7)` `(14)`
* BidirectionalIterator begin                            `(7)` `(15)`
* RandomAccessIterator  begin                            `(7)` `(15)`
* ForwardIterator       begin, ForwardIterator       end `(6)` `(15)`
* BidirectionalIterator begin, BidirectionalIterator end `(6)` `(15)`
* RandomAccessIterator  begin, RandomAccessIterator  end `(6)` `(15)`

`OutputParams` may be one of the following sets of parameters:

* OutputFunctor        output                          `(1)` `(9)`
* OutputFunctor        output, WindowFunctor window    `(2)`
* OutputIterator       target                          `(9)`
* RandomAccessIterator target                                           `(10)`
* RandomAccessIterator target,   SizeType target_limit            `(3)` `(10)`
* RandomAccessIterator target,   RandomAccessIterator target_end  `(4)` `(10)`


1) If the output functor (`output`) returns a `bool`, and the returned value is `true`, the decompression aborts with return value -3
without writing any more data.

2) If the output functor (`output`) returns a `bool`, and the returned value is `true`, the decompression aborts with return value -3
without writing any more data.
If the window function returns an integer type, and the returned value is other than 0, the decompression aborts with return value -4
without writing any more data.
If either the window function returns `void`, or the output functor does not return a `bool`, aborting on output-full will not be compiled.

3) If `target_limit` bytes have been written into `target` and the decompression is not yet complete, the decompression aborts with return value -3
without writing any more data.

4) If `target_begin == target_end`, the decompression aborts with return value -3
without writing any more data.

5) If the input functor (`input`) returns an integer type other than a `char`, `signed char`, or `unsigned char`,
and the returned value is smaller than 0 or larger than 255, the decompression aborts with return value -2
without reading any more data.

6) If `begin == end`, the decompression aborts with return value -2.

7) If the input iterator deferences into a value outside the 0 — 255 range, the decompression aborts with return value -2
without reading any more data.

8) If `length` bytes have been read from `begin` and the decompression is not yet complete, the decompression aborts with return value -2
without reading any more data.

9) A separate 32768-byte sliding window will be automatically and separately allocated for the decompression.

10) The output data buffer is assumed to persist during the call and doubles as the sliding window for the decompression.

11) The `first` field in the return value has the same meaning as the `int` type return value described earlier.    
The `second` field in the return value contains the number of bytes that were consumed from the input.

12) The `first` field in the return value has the same meaning as the `int` type return value described earlier.    
The `second` field in the return value contains the number of bytes that were written to the output.

13) The `first` field in the return value has the same meaning as the `int` type return value described earlier.    
The `second.first` field in the return value contains the number of bytes that were consumed from the input.    
The `second.second` field in the return value contains the number of bytes that were written to the output.

14) This method is non-backtrackable, and uses a bit more memory than the backtrackable ones.

15) This method is backtrackable, meaning that some bytes in the input may be read twice. It uses less memory than the non-backtrackable calls. 

### Tips

Some of these definitions may be ambiguous.
If you hit a compiler error, choose a different call method.
To help distinguish between (`InputIterator`,`RandomAccessIterator`,`RandomAccessIterator`)
and (`ForwardIterator`,`ForwardIterator`,`OutputIterator`), make sure the input iterators
are _const_.

If you do multiple decompression calls in your program in different spots,
it may be wise to make sure they all use the same type of parameters,
to avoid having to instantiate multiple copies of `Deflate()`.
Lambda functors are an offender in this respect, because each lambda has a
unique type even if their contents and calling conventions are identical.
In the worst case, you can use `std::function` to wrap your calls
into a common interface. Check out this video for more about this topic: https://www.youtube.com/watch?v=rUB5Hlm9AaQ

## Requirements

```C++
// An InputFunctor has the following prototype,
// wherein type1 is convertible into unsigned char:
type1 input()

// An OutputFunctor has one of the following two prototypes,
// wherein type1 can accept unsigned int parameters in range 0-255:
void output(type1 byte_to_output)
bool output(type1 byte_to_output)

// A WindowFunctor has one of the following two prototypes,
// wherein type1 can accept unsigned int parameters in range 0-258,
// and     type2 can accept unsigned int parameters:
void  outputcopy(type1 length, type2 offs)
type2 outputcopy(type1 length, type2 offs)

// An InputIterator must have at least the following operations defined,
// where type1 is convertible into unsigned char:
const type1& operator*() const
InputIterator& operator++()

// A OutputIterator must have at least the following operations defined,
// where type1 is convertible into unsigned char:
type1& operator*() const
OutputIterator& operator++()

// A ForwardIterator must have at least the following operations defined,
// where type1 is convertible into unsigned char:
const type1& operator*() const
ForwardIterator& operator++()
bool operator==(const ForwardIterator&) const

// A RandomAccessIterator must have at least the following operations defined,
// where type1 is convertible into unsigned char,
// and type2 is a signed integer type (may be negative):
type1& operator*()
type1& operator[] (type2)
RandomAccessIterator operator- (type2)
RandomAccessIterator& operator++()
bool operator==(const RandomAccessIterator&) const
```

## Example use:

Decompress the standard input into the standard output (uses 32 kB automatically allocated window):

```C++
    Deflate([]()                   { return std::getchar(); },
            [](unsigned char byte) { std::putchar(byte); });
    
    // Or more simply:
    
    Deflate(std::getchar, std::putchar);
```

Decompress an array containing gzipped data into another array that must be large enough to hold the result.
A window buffer will not be allocated.

```C++
    extern const char compressed_data[];
    extern unsigned char outbuffer[131072];
    
    Deflate(compressed_data+0, outbuffer+0);
```

Same as above, but with range checking for output, and reporting of written size:

```C++
    extern const char compressed_data[];
    extern unsigned char outbuffer[131072];
    
    auto result = Deflate(compressed_data+0, outbuffer+0, sizeof(outbuffer), DeflateTrackOutSize{});
    if(result.first != 0) std::fprintf(stderr, "Error %d\n", result.first);
    std::fprintf(stderr, "%u bytes written\n", unsigned(result.second));
```

Same as above, but with range checking for both input and output:

```C++
    extern const char compressed_data[];
    extern unsigned compressed_data_length;
    extern unsigned char outbuffer[131072];
    
    int result = Deflate(compressed_data+0, compressed_data_length, outbuffer, outbuffer + sizeof(outbuffer));
    if(result != 0) std::fprintf(stderr, "Error\n");
```

Decompress using a custom window function (the separate 32 kB window buffer will not be allocated):

```C++
    std::vector<unsigned char> result;
    
    Deflate(std::getchar,
            [&](unsigned byte)
            {
                result.push_back(byte);
            },
            [&](unsigned length, unsigned offset)
            {
                 if(!length)
                 {
                     // offset contains the maximum look-behind distance.
                     // You could use this information to allocate a buffer of a particular size.
                     // length=0 case is invoked exactly once before any length!=0 cases are.
                 }
                 while(length-- > 0)
                 {
                     result.push_back( result[result.size()-offset] );
                 }
            });
```

Same as above, but stop decompressing once 4096 bytes have been written:

```C++
    std::vector<unsigned char> result;
    
    Deflate(std::getchar,
            [&](unsigned byte)
            {
                if(result.size() >= 4096) return true;
                result.push_back(byte);
                return false;
            },
            [&](unsigned length, unsigned offset)
            {
                 if(!length)
                 {
                     // offset contains the maximum look-behind distance.
                     // You could use this information to allocate a buffer of a particular size.
                     // length=0 case is invoked exactly once before any length!=0 cases are.
                 }
                 for(; result.size() < 4096 && length > 0; --length)
                 {
                     result.push_back( result[result.size()-offset] );
                 }
                 return length;
            });
```

## Misnomer

Yes, I am aware that the project is technically named misleadingly.
This project implements the _inflate_ algorithm (decompression),
not _deflate_ (compression).

In my defense, the _compression format_ is called deflate. There is no _inflate_ format.
This library decompresses data that has been compressed with _deflate_.

Think name, not verb.





/* My tiny gzip decompressor without using zlib. - Joel Yliluoma
 * http://iki.fi/bisqwit/ , http://youtube.com/user/Bisqwit
 * Inspired and influenced by a 13th IOCCC winner program by Ron McFarland */
/* Further optimized based on ideas from tinf library by Joergen Ibsen */
/** @file gunzip.hh @brief TinyDeflate */

/* Fun fact: Contains zero new/delete, and no STL data structures */
/* Distributed under the terms of the Zlib license:

  Copyright (C) 2018 Joel Yliluoma

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include <assert.h>
#include <utility>     // std::forward
#include <cstdint>     // integer sizes
#include <type_traits>
#include <iterator>

#if !1 //Documentation purposes only; the actual prototypes are littered with std::enable_ifs.
/// Deflate(): This is the public method declared (later) in this file.
/// Decompresses (inflates) deflate-compressed data, with a gzip or deflate header.
/// User-supplied functors:
/// @param  input() returns the next byte from the (compressed) input.
/// @param  output(byte) outputs one uncompressed byte.
/// @param  outputcopy(length, offset) copies length uncompressed bytes from offset,
///       Offset is always >= 1.
///       offset 1 means previous byte,
///       offset 2 means previous before that and so on.
///       Note that (offset < length) is not an error and in fact happens frequently.
///       If length=0, offset indicates the largest look-behind window length that
///       you need to be prepared for. The length is a power-of-two in range 256..32768.
//
/// If you want to implement range checking in input, return a negative value
/// from input() when there is no more input.
//
/// If you want to implement range checking in output, add a return value
/// in output(): false=ok, true=abort; and a return value in outputcopy():
/// 0=ok, nonzero=one or more bytes were not writable.
//
/// @returns:
///       0 = decompression complete
///      -1 = data error
///      -2 = input functor returned a value outside 0x00..0xFF range
///      -3 = output functor returned nonzero / bool true value
///      -4 = outputcopy functor returned nonzero remaining length value
//
template<typename InputFunctor, typename OutputFunctor, typename WindowFunctor>
int Deflate(InputFunctor&& input, OutputFunctor&& output, WindowFunctor&& outputcopy);

/// Check README.md for the full list of versions of Deflate() available.

#endif

struct DeflateTrackTagBase{};
struct DeflateTrackNoSize: public DeflateTrackTagBase{};
struct DeflateTrackInSize: public DeflateTrackTagBase{};
struct DeflateTrackOutSize: public DeflateTrackTagBase{};
struct DeflateTrackBothSize: public DeflateTrackTagBase{};


/// The rest of the file is just for the curious about implementation.
#ifndef DOXYGEN_SHOULD_SKIP_THIS
namespace gunzip_ns
{
    //#define DO_DEFDB_DUMPING

    // If you want more performance at the expense of RAM use,
    // Turn one or more of these settings to false:
    static constexpr bool USE_BITARRAY_TEMPORARY_IN_HUFFMAN_CREATION = false; /* 8 bytes save */
    static constexpr bool USE_BITARRAY_FOR_LENGTHS = false;                   /* 160 bytes save */
    static constexpr bool USE_BITARRAY_FOR_HUFFNODES = false;                 /* 392 bytes save */

    static constexpr unsigned MAX_WINDOW_SIZE = 32768u;

    static_assert(MAX_WINDOW_SIZE >= 1,      "Max window size should be >= 1");
    static_assert(MAX_WINDOW_SIZE <= 32768u, "Window sizes larger than 32768 are not supported by deflate standard. Edit the source code to remove this assert if you need it.");

    //
    #define DEFLATE_USE_DATA_TABLES

    #if !defined(DEFLATE_ALLOCATION_AUTOMATIC) && !defined(DEFLATE_ALLOCATION_STATIC) && !defined(DEFLATE_ALLOCATION_DYNAMIC)
    // Choose one:
    #define DEFLATE_ALLOCATION_AUTOMATIC
    //#define DEFLATE_ALLOCATION_STATIC
    //#define DEFLATE_ALLOCATION_DYNAMIC
    #endif

    constexpr unsigned Flag_InputAbortable  = 0x01;
    constexpr unsigned Flag_OutputAbortable = 0x02;
    constexpr unsigned Flag_TrackIn  = 0x40;
    constexpr unsigned Flag_TrackOut = 0x80;
    constexpr unsigned Flag_NoTrackFlagMask = 0x03;
}

#ifdef DEFLATE_ALLOCATION_DYNAMIC
# include <memory>
#endif

// RandomAccessBitArray: An engine for arrays of data items that are not byte-aligned
template<typename U = std::uint_least64_t>
struct RandomAccessBitArrayBase
{
private:
    static constexpr unsigned Ubytes = sizeof(U), Ubits = Ubytes*8;

    static std::uint_fast64_t Get_Unclean(unsigned Size, const U* data, unsigned index) throw()
    {
        unsigned bitpos = index*Size, unitpos = bitpos / Ubits, shift = bitpos % Ubits;
        std::uint_fast64_t result = data[unitpos] >> shift;
        //assert(Size <= sizeof(result)*8);
        unsigned acquired = Ubits - shift;
        for(; acquired < Size; acquired += Ubits)
        {
            result += (std::uint_fast64_t)data[++unitpos] << acquired;
        }
        return result;
    }
public:
    template<unsigned Size>
    static std::uint_fast64_t Get(const U* data, unsigned index) throw()
    {
        std::uint_fast64_t result = Get_Unclean(Size,data,index);
        return (Size >= sizeof(result)*8) ? result : (result & ((std::uint64_t(1) << Size)-1));
    }

    template<unsigned Size, bool update = false>
    static void Set(U* data, unsigned index, std::uint_fast64_t value) throw()
    {
        unsigned bitpos = index*Size, unitpos = bitpos / Ubits, eat = 0;
        // Make sure our storage unit is at least as bit as value
        //assert(Ubits >= sizeof(value)*8);
        //assert(Size >= sizeof(value)*8 || value < (std::uint64_t(1) << Size));

        if(Size % Ubits != 0)
        {
            unsigned shift = bitpos % Ubits;
            eat = Ubits - shift; if(eat > Size) eat = Size;

            //assert(eat < sizeof(std::uint_fast64_t)*8);
            //assert(shift + eat <= Ubits);
            std::uint_fast64_t vmask = (std::uint64_t(1) << eat)-1;
            if(update)
                data[unitpos] = (data[unitpos] & ~(vmask << shift)) | (value << shift);
            else
                data[unitpos] |= value << shift;
            //assert(eat < sizeof(value)*8);
            value >>= eat;
            ++unitpos;
        }
        if(eat < Size)
            for(unsigned remain = Size-eat; ; ++unitpos)
            {
                eat = Ubits;
                if(eat > remain)
                {
                    eat = remain;
                    if(update)
                    {
                        std::uint_fast64_t vmask = ((std::uint64_t(1) << eat)-1);
                        data[unitpos] = (data[unitpos] & ~vmask) | value;
                    }
                    else
                    {
                        data[unitpos] |= value;
                    }
                    break;
                }
                else
                {
                    data[unitpos] = value;
                    value >>= Ubits/2; value >>= Ubits/2;
                    remain -= Ubits;
                    if(!remain) break;
                }
            }
    }
};

template<unsigned Nbits, typename U = std::uint_least64_t>
struct RandomAccessBitArray
{
    static constexpr unsigned Ubytes = sizeof(U), Ubits = Ubytes*8, Nunits = (Nbits+Ubits-1)/Ubits;
    U data[Nunits];

    template<unsigned Size>
    inline std::uint_fast64_t Get(unsigned index) const throw()
    {
        return RandomAccessBitArrayBase<U>::template Get<Size>(data, index);
    }

    template<unsigned Size, bool update = false>
    inline void Set(unsigned index, std::uint_fast64_t value) throw()
    {
        RandomAccessBitArrayBase<U>::template Set<Size,update>(data, index, value);
    }
};

namespace gunzip_ns
{
    struct dummy{};

    /// Utility: ceil(log2(n))
    template<unsigned long N> struct CeilLog2_s{ static constexpr unsigned result = 1+CeilLog2_s<(N+1)/2>::result; };
    template<> struct CeilLog2_s<0> { static constexpr unsigned result = 0; };
    template<> struct CeilLog2_s<1> { static constexpr unsigned result = 0; };
    template<unsigned long N> static constexpr unsigned CeilLog2 = CeilLog2_s<N>::result;

    /// Utility: floor(log2(n))
    template<unsigned long N> struct FloorLog2_s{ static constexpr unsigned result = 1+FloorLog2_s<N/2>::result; };
    template<> struct FloorLog2_s<0> { static constexpr unsigned result = 0; };
    template<> struct FloorLog2_s<1> { static constexpr unsigned result = 0; };
    template<unsigned long N> static constexpr unsigned FloorLog2 = FloorLog2_s<N>::result;

    /// Utility: smallest unsigned integer type that can store n-bit value
    template<unsigned bits>
    using SmallestType = std::conditional_t< (bits<=16),
                         std::conditional_t< (bits<= 8), std::uint_least8_t,  std::uint_least16_t>,
                         std::conditional_t< (bits<=32), std::uint_least32_t, std::uint_least64_t>>;

    /// testcases
    static_assert(FloorLog2<1> == 0, "FloorLog2 fail"); static_assert(CeilLog2<1> == 0, "CeilLog2 fail");
    static_assert(FloorLog2<2> == 1, "FloorLog2 fail"); static_assert(CeilLog2<2> == 1, "CeilLog2 fail");
    static_assert(FloorLog2<3> == 1, "FloorLog2 fail"); static_assert(CeilLog2<3> == 2, "CeilLog2 fail");
    static_assert(FloorLog2<4> == 2, "FloorLog2 fail"); static_assert(CeilLog2<4> == 2, "CeilLog2 fail");
    static_assert(FloorLog2<5> == 2, "FloorLog2 fail"); static_assert(CeilLog2<5> == 3, "CeilLog2 fail");
    static_assert(FloorLog2<6> == 2, "FloorLog2 fail"); static_assert(CeilLog2<6> == 3, "CeilLog2 fail");
    static_assert(FloorLog2<7> == 2, "FloorLog2 fail"); static_assert(CeilLog2<7> == 3, "CeilLog2 fail");
    static_assert(FloorLog2<8> == 3, "FloorLog2 fail"); static_assert(CeilLog2<8> == 3, "CeilLog2 fail");
    static_assert(FloorLog2<9> == 3, "FloorLog2 fail"); static_assert(CeilLog2<9> == 4, "CeilLog2 fail");

    template<bool packed, unsigned Dimension, unsigned ElementSize>
    struct RandomAccessArray {};

    template<unsigned Dim, unsigned Elem>
    struct RandomAccessArray<true, Dim, Elem>
    {
        RandomAccessBitArray<Dim*Elem> impl;
        inline std::uint_fast64_t Get(unsigned index) const { return impl.template Get<Elem>(index); }
        inline void Set(unsigned index, std::uint_fast32_t value)  { impl.template Set<Elem,true>(index, value); }
        inline void QSet(unsigned index, std::uint_fast32_t value) { impl.template Set<Elem,false>(index, value); }
        template<unsigned Bits>
        inline void WSet(unsigned index, std::uint_fast64_t value) { impl.template Set<Bits,true>(index, value); }
    };

    template<unsigned Dim, unsigned Elem>
    struct RandomAccessArray<false, Dim, Elem>
    {
        typedef SmallestType<Elem> E;
        E data[Dim];
        inline E Get(unsigned index) const        { return data[index]; }
        inline void Set(unsigned index, E value)  { data[index] = value; }
        inline void QSet(unsigned index, E value) { data[index] = value; }
        template<unsigned Bits>
        inline void WSet(unsigned index, std::uint_fast64_t value)
        {
            index *= Bits/Elem;
            for(unsigned b=0; b<Bits; b+=Elem, value>>=Elem)
                QSet(index++, (value % (1u << Elem)));
        }
    };
}


namespace gunzip_ns
{
    //#define DEFL_DO_HUFF_STATS
    template<bool Abortable, unsigned A,unsigned B, typename LengthFunctor>
    bool CreateHuffmanTree(const char*
                           #ifdef DEFL_DO_HUFF_STATS
                                       why
                           #endif
                           , RandomAccessArray<USE_BITARRAY_FOR_HUFFNODES,A,B>& tree,
                           unsigned num_values,
                           LengthFunctor&& ReadLength) throw()
    {
        /* Lengths[] needs to be scanned exactly twice, in forward order.
         * Technically we could use a functor instead of a table,
         * but this would require that the dynamic tree generator
         * can read sections of the compressed data twice,
         * which we currently do not support.
         */

        constexpr unsigned ElemBits = CeilLog2<A-15>; // ceil(log2(A-15)) where A-15 is max value of num_values
        static_assert((1u << B) >= (A-15), "B is too small");
        assert(num_values <= (A-15));

        RandomAccessArray<USE_BITARRAY_TEMPORARY_IN_HUFFMAN_CREATION, 15, ElemBits> offs{}; // 24 or 16 bytes.
        // Theoretically 15.32 bytes for 288 num_values, 9.375 for 32 num_values, 7.97 for 19 num_values.

        // Clear code length count table
        tree.template WSet<(15*B + 63) & ~63>(0, 0); // First 15 needed, but round to nice unit
        // Scan symbol length, and sum code length counts
        #ifdef DEFL_DO_HUFF_STATS
        unsigned largest_treetable_value = 0, largest_offs = 0, smallest_treetable_value = ~0u;
        unsigned largest_treetrans_index=0, largest_treetrans_value=0;
        unsigned longest_length = 0;
        #endif
        for(unsigned a = 0; a < num_values; ++a)
        {
            int length = ReadLength(a); // Note: Can be zero.
            if(Abortable && length < 0) return true;
            if(length)
            {
                unsigned v = tree.Get(0 + length-1)+1;
            #ifdef DEFL_DO_HUFF_STATS
                largest_treetable_value = std::max(largest_treetable_value, v);
                longest_length          = std::max(longest_length, unsigned(length));
            #endif
                //fprintf(stderr, " [%d]%3d CLL (val: %d)\n", length, v, v);
                tree.Set(0 + length-1, v);
            }
            else
            {
                //fprintf(stderr, " [_]%3d CLL (val: 0)\n", 0);
            }
        }

        // Compute offset table for distribution sort
        for(unsigned sum=0, a = 1; a < 16; ++a)
        {
            offs.QSet(a-1, sum);      // starting offset for values that have length "a"
            sum += tree.Get(0 + a-1); // number of values that have length "a"
        }
        #ifdef DEFL_DO_HUFF_STATS
        for(unsigned a=1; a<=longest_length; ++a)
            smallest_treetable_value = std::min(smallest_treetable_value, (unsigned)tree.Get(0 + a-1));
        #endif

        // Create code->symbol translation table (symbols sorted by code)
        for(unsigned value = 0; value < num_values; ++value)
        {
            int length = ReadLength(value); // Note: Can be zero.
            if(Abortable && length < 0) return true;
            if(length)
            {
                unsigned q = offs.Get(length-1); offs.Set(length-1, q+1); // q = offset[length]++;
        #ifdef DEFL_DO_HUFF_STATS
                largest_offs = std::max(q, largest_offs);
                largest_treetrans_index = std::max(largest_treetrans_index, q);
                largest_treetrans_value = std::max(largest_treetrans_value, value);
        #endif
                assert(q < num_values /*&& value < num_values*/);
                //fprintf(stderr, " [x]%3d CLL %d\n", 15+q, value);
                tree.Set(15 + q, value);
            }
        }
        #ifdef DEFL_DO_HUFF_STATS
        std::fprintf(stderr, "Largest \"%12s\"(treetable_value=%4u..%4u, offs=%4u, treetrans_index=%4u, treetrans_value=%4u)\n",
            why, smallest_treetable_value,largest_treetable_value,
            largest_offs, largest_treetrans_index, largest_treetrans_value);
        #endif

        // Largest values observed in the wild:

        // Dyn Lengths: Max treetable_value =255, max offs =285, max treetrans_index =285, max treetrans_value =285
        // Stat Lengths:Max treetable_value =152, max offs =287, max treetrans_index =287, max treetrans_value =287

        // Len Lengths: Max treetable_value = 13, max offs = 18, max treetrans_index = 18, max treetrans_value = 18
        // Dyn Dists:   Max treetable_value = 19, max offs = 29, max treetrans_index = 29, max treetrans_value = 29
        // Stat Dists:  Max treetable_value = 32, max offs = 31, max treetrans_index = 31, max treetrans_value = 31
        return false;
    }

#ifdef DEFLATE_USE_DATA_TABLES
    template<bool=0> // Using a dummy template parameter makes this function and its data weak,
    inline const std::uint_least8_t* GetBTable() throw() // removing linker problems in multi-module use
    {
        static const std::uint_least8_t data[] {
            // Length bases (0-31)
            0,1,2,3,4,5,6,7,8,10,12,14,16,20,24,28,32,40,48,56,64,80,96,112,128,160,192,224,255, 0,0,0,
            // Length bits and distance bits (29-60) (overlap 3 bytes)
            //               0x00,0x01,0x01,0x02,0x02,0x13,0x13,0x14,0x14,0x25,0x25,0x26,0x26,
            //0x37,0x37,0x38,0x38,0x49,0x49,0x4A,0x4A,0x5B,0x5B,0x5C,0x5C,0x0D,0x0D,0x00,0x00
            // Reverse-order table
            3*3,17*3,15*3,13*3,11*3,9*3,7*3,5*3,4*3,6*3,8*3,10*3,12*3,14*3,16*3,18*3,0*3,1*3,2*3
        };
        return data;
    }
    //template<bool=0>
    //inline const std::uint_least16_t* GetWTable() throw()
    //{
    //    static const std::uint_least16_t data[32] {
    //         1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577, 0,0 };
    //    return data;
    //}

    //inline unsigned dbase(unsigned distcode) { return GetWTable<>()[distcode]; }
    inline unsigned lbase(unsigned lencode)  { return GetBTable<>()[lencode-257+0] + 3; }
    //inline unsigned dbits(unsigned distcode) { return GetBTable<>()[distcode+29] & 0xF; }
    //inline unsigned lbits(unsigned lencode) { return GetBTable<>()[lencode-257+29] >> 4; }
    inline unsigned rshift(unsigned a)       { return GetBTable<>()[a + 32]; }
#else
    inline unsigned lbase(unsigned lencode)  { return (lencode > 285 ? 3 : ((lencode >= 265) ? (((lencode-257)%4+4) << ((lencode-257)/4-1)) + (lencode==285 ? 2 : 3) : (lencode-254))); }
    inline unsigned rshift(unsigned a)       { if(!a) return 3*3; else if(a>=16) return (a-16)*3; int r = 12 + 7*(a<8) - a*2; return (r<0 ? -r : r)*3; }
#endif
    inline unsigned dbase(unsigned distcode) { return (1 + (distcode>=4 ? ((2+distcode%2) << (distcode/2-1)) : distcode)); }
    inline unsigned dbits(unsigned distcode) { return distcode>=4 ? distcode/2-1 : 0; }
    inline unsigned lbits(unsigned lencode)  { return ((lencode>=265 && lencode<285) ? ((lencode-265)/4+1) : 0); }
    //inline unsigned order(unsigned index)    { return index<3 ? (index+16) : ((index%2) ? (1-index/2)&7 : (6+index/2)); }

    //                            Cortex-M0+      Cortex-M4       x86_64
    // dbase with table           12+64 = 76      12+64 = 76      14+64 = 78
    // dbase with func                    24              22              26
    // lbase with table           12+32 = 48      12+32 = 48      21+64 = 76
    // lbase with func                    54              56              64
    // dbits+lbits with table  12+16+29 = 57   12+16+29 = 57   17+21+29 = 67
    // dbits+lbits with func      14+18 = 32      14+18 = 32      13+20 = 33

    // Support for pre-c++20
    template<typename T>
    using remove_cvref_t = std::remove_reference_t<std::remove_cv_t<T>>;
    // Support for pre-c++20 (result_of is removed in c++20, invoke_result is added in c++17, so neither can be used exclusively)
    template <class T>
    struct result_of { // explain usage
        static_assert((T)false, "result_of<CallableType> is invalid; use "
            "result_of<CallableType(zero or more argument types)> instead.");
    };
    #if __cplusplus > 202000UL
    template <typename F, typename... Args>
    struct result_of<F(Args...)> : std::invoke_result<F, Args...> {};
    #else
    template <typename F, typename... Args>
    struct result_of<F(Args...)> : std::result_of<F(Args...)> {};
    #endif
    template <class T>
    using result_of_t = typename result_of<T>::type;

    #define BEGIN_COND(name) \
        template<typename T, typename=void> struct name : public std::false_type {}; \
        template<typename T> struct name<T, std::enable_if_t<
    #define END_COND(name) \
        , void>> : public std::true_type {}; \
        template<typename T> \
        inline constexpr bool name ## _v = name<T>::value; \

    // Input parameter condition testers:
    BEGIN_COND(is_input_functor)
        std::is_convertible_v<result_of_t<remove_cvref_t<T>()>,int>
    END_COND(is_input_functor)
    BEGIN_COND(is_input_iterator)
        std::is_convertible_v<typename std::iterator_traits<remove_cvref_t<T>>::value_type, unsigned char>
     && std::is_same_v<typename std::iterator_traits<remove_cvref_t<T>>::iterator_category, std::input_iterator_tag>
    END_COND(is_input_iterator)
    BEGIN_COND(is_bidir_input)
        std::is_convertible_v<typename std::iterator_traits<remove_cvref_t<T>>::value_type, unsigned char>
     && (std::is_same_v<typename std::iterator_traits<remove_cvref_t<T>>::iterator_category, std::forward_iterator_tag>
      || std::is_same_v<typename std::iterator_traits<remove_cvref_t<T>>::iterator_category, std::bidirectional_iterator_tag>
      || std::is_same_v<typename std::iterator_traits<remove_cvref_t<T>>::iterator_category, std::random_access_iterator_tag>)
    END_COND(is_bidir_input)
    BEGIN_COND(is_size_type)
        std::is_convertible_v<remove_cvref_t<T>, std::size_t> && !std::is_pointer_v<remove_cvref_t<T>>
    END_COND(is_size_type)
    // Output parameter condition testers:
    BEGIN_COND(is_random_iterator)
        std::is_convertible_v<typename std::iterator_traits<remove_cvref_t<T>>::value_type, unsigned char>
     && !std::is_const_v<typename std::iterator_traits<remove_cvref_t<T>>::reference>
     && std::is_same_v<typename std::iterator_traits<remove_cvref_t<T>>::iterator_category, std::random_access_iterator_tag>
    END_COND(is_random_iterator)
    BEGIN_COND(is_output_iterator)
        std::is_convertible_v<typename std::iterator_traits<remove_cvref_t<T>>::value_type, unsigned char>
    && !std::is_const_v<typename std::iterator_traits<remove_cvref_t<T>>::reference>
                                && !std::is_pointer_v<remove_cvref_t<T>>
    && (std::is_same_v<typename std::iterator_traits<remove_cvref_t<T>>::iterator_category, std::output_iterator_tag>
     || std::is_same_v<typename std::iterator_traits<remove_cvref_t<T>>::iterator_category, std::forward_iterator_tag>
     || std::is_same_v<typename std::iterator_traits<remove_cvref_t<T>>::iterator_category, std::bidirectional_iterator_tag>)
    END_COND(is_output_iterator)
    // Output functor & window functor: Returns void or something that can be converted to bool
    BEGIN_COND(is_output_functor)
        std::is_same_v<result_of_t<remove_cvref_t<T>(int)>,void> || std::is_convertible_v<result_of_t<remove_cvref_t<T>(int)>,bool>
    END_COND(is_output_functor)
    BEGIN_COND(is_window_functor)
        std::is_same_v<result_of_t<remove_cvref_t<T>(int,int)>,void> || std::is_convertible_v<result_of_t<remove_cvref_t<T>(int,int)>,int>
    END_COND(is_window_functor)

    BEGIN_COND(is_abortable_input_type)
        !(std::is_same_v<T, unsigned char> || std::is_same_v<T, signed char> || std::is_same_v<T, char>)
    END_COND(is_abortable_input_type)

    #undef END_COND
    #undef BEGIN_COND

    template<typename T>
    constexpr bool DeflAbortable_InFun  = is_abortable_input_type_v<remove_cvref_t<result_of_t<T()>>>;
    template<typename T>
    constexpr bool DeflAbortable_OutFun = std::is_same_v<result_of_t<T(int)>, bool>;
    template<typename T>
    constexpr bool DeflAbortable_WinFun = std::is_convertible_v<remove_cvref_t<result_of_t<T(int,int)>>, int>;

    template<bool Abortable>
    struct OutputHelper
    {
        template<typename OutputFunctor>
        static inline bool output(OutputFunctor&& output, unsigned char byte)
        {
            output(byte);
            return false;
        }
        template<typename WindowFunctor>
        static inline bool outputcopy(WindowFunctor&& outputcopy, std::uint_least16_t length, std::uint_fast32_t offset)
        {
            outputcopy(length, offset);
            return false;
        }
    };

    template<>
    struct OutputHelper<true>
    {
        template<typename OutputFunctor>
        static inline bool output(OutputFunctor&& output, unsigned char byte)
        {
            return output(byte);
        }
        template<typename WindowFunctor>
        static inline bool outputcopy(WindowFunctor&& outputcopy, std::uint_least16_t& length, std::uint_fast32_t offset)
        {
            length = outputcopy(length, offset);
            return length != 0;
        }
    };

    struct SizeTracker_NoOutput
    {
        inline void OutByte()                    { }
        inline void OutBytes(std::uint_fast64_t) { }

        // Dummy forwarders. Do the same as std::forward.
        template<typename T>
        static inline constexpr T&& ForwardOutput(std::remove_reference_t<T>& fun) { return static_cast<T&&>(fun); }
        template<typename T>
        static inline constexpr T&& ForwardOutput(std::remove_reference_t<T>&& fun) { return static_cast<T&&>(fun); }

        template<typename T>
        static inline constexpr T&& ForwardWindow(std::remove_reference_t<T>& fun) { return static_cast<T&&>(fun); }
        template<typename T>
        static inline constexpr T&& ForwardWindow(std::remove_reference_t<T>&& fun) { return static_cast<T&&>(fun); }
    };
    struct SizeTracker_NoInput
    {
        inline void InByte()                    { }
        inline void InBytes(std::uint_fast64_t) { }

        template<typename T>
        static inline constexpr T&& ForwardInput(std::remove_reference_t<T>& fun) { return static_cast<T&&>(fun); }
        template<typename T>
        static inline constexpr T&& ForwardInput(std::remove_reference_t<T>&& fun) { return static_cast<T&&>(fun); }
    };
    struct SizeTracker_DoInput
    {
        std::uint_fast64_t insize=0;

        inline void InByte()                      { ++insize; }
        inline void InBytes(std::uint_fast64_t n) { insize += n; }

        template<typename InputFunctor, std::enable_if_t<!DeflAbortable_InFun<InputFunctor>,gunzip_ns::dummy>...>
        auto ForwardInput(const InputFunctor& input)
        {
            return [&]() { InByte(); return input(); };
        }

        template<typename InputFunctor, std::enable_if_t<DeflAbortable_InFun<InputFunctor>,gunzip_ns::dummy>...>
        auto ForwardInput(const InputFunctor& input)
        {
            return [&]() { auto r = input(); if(!(r & ~0xFF)) { InByte(); } return r; };
        }
    };
    struct SizeTracker_DoOutput
    {
        std::uint_fast64_t outsize=0;

        inline void OutByte()                      { ++outsize; }
        inline void OutBytes(std::uint_fast64_t n) { outsize += n; }

        template<typename OutputFunctor, std::enable_if_t<!DeflAbortable_OutFun<OutputFunctor>,gunzip_ns::dummy>...>
        auto ForwardOutput(const OutputFunctor& output)
        {
            return [&](unsigned char byte) { OutByte(); return output(byte); };
        }

        template<typename OutputFunctor, std::enable_if_t<DeflAbortable_OutFun<OutputFunctor>,gunzip_ns::dummy>...>
        auto ForwardOutput(const OutputFunctor& output)
        {
            return [&](unsigned char byte) { auto r = output(byte); if(!r) { OutByte(); } return r; };
        }

        template<typename WindowFunctor, std::enable_if_t<!DeflAbortable_WinFun<WindowFunctor>,gunzip_ns::dummy>...>
        auto ForwardWindow(const WindowFunctor& outputcopy)
        {
            return [&](std::uint_least16_t length, std::uint_fast32_t offset)
            {
                OutBytes(length);
                return outputcopy(length, offset);
            };
        }

        template<typename WindowFunctor, std::enable_if_t<DeflAbortable_WinFun<WindowFunctor>,gunzip_ns::dummy>...>
        auto ForwardWindow(const WindowFunctor& outputcopy)
        {
            return [&](std::uint_least16_t length, std::uint_fast32_t offset)
            {
                auto remain = outputcopy(length, offset);
                OutBytes(length - remain);
                return remain;
            };
        }
    };

    template<typename TrackType>
    struct SizeTracker: public SizeTracker_NoOutput, public SizeTracker_NoInput
    {
        inline int operator() (int returncode) const { return returncode; }
    };
    template<>
    struct SizeTracker<DeflateTrackOutSize>: public SizeTracker_NoInput, public SizeTracker_DoOutput
    {
        typedef std::pair<int,std::uint_fast64_t> result;
        inline result operator() (int returncode) const { return result{returncode,outsize}; }
    };
    template<>
    struct SizeTracker<DeflateTrackInSize>: public SizeTracker_NoOutput, public SizeTracker_DoInput
    {
        typedef std::pair<int,std::uint_fast64_t> result;
        inline result operator() (int returncode) const { return result{returncode,insize}; }
    };
    template<>
    struct SizeTracker<DeflateTrackBothSize>: public SizeTracker_DoInput, public SizeTracker_DoOutput
    {
        typedef std::pair<int, std::pair<std::uint_fast64_t,std::uint_fast64_t>> result;
        inline result operator() (int returncode) const { return result{returncode,std::make_pair(insize,outsize)}; }
    };

    #ifdef DO_DEFDB_DUMPING
    unsigned bitcounter=0;
    #endif
    struct DeflateBitCache
    {
        std::uint_least8_t BitCache = 0, BitCount = 0;

        template<bool Abortable, typename InputFunctor>
        std::uint_least64_t GetBits(InputFunctor&& input, unsigned numbits)
        {
            #ifdef DO_DEFDB_DUMPING
            bitcounter += numbits;
            #endif
            std::uint_fast64_t result = BitCache;
            if(numbits <= BitCount)
            {
                BitCount -= numbits;
                BitCache >>= numbits;
                result &= ((1u << numbits)-1); // 0-8
                return result;
            }
            for(unsigned acquired = BitCount; ; acquired += 8)
            {
                unsigned byte = input();
                if(Abortable && (byte & ~0xFFu))
                {
                    // Note: Throws away bits already eaten from BitCache
                    return ~std::uint_least64_t(0); // error
                }
                unsigned eat = numbits-acquired;
                byte &= 0xFF;
                if(eat <= 8)
                {
                    result |= ((std::uint_fast64_t)(byte & ((1u << eat)-1))) << acquired;
                    BitCount =       8-eat;
                    BitCache = byte >> eat;
                    return result;
                }
                result |= ((std::uint_fast64_t)(byte)) << acquired;
            }
        }

        template<bool Abortable, typename InputFunctor, unsigned A,unsigned B>
        std::uint_least32_t HuffRead(InputFunctor&& input,
                                     RandomAccessArray<USE_BITARRAY_FOR_HUFFNODES,A,B>& tree)
        {
            int sum=0, cur=0, len=0;
            #ifdef DEFL_DO_HUFF_STATS
            static int maxlen = 0;
            #endif
            // Get more bits while code value is above sum
            do {
                auto p = GetBits<Abortable>(std::forward<InputFunctor>(input), 1);
                if(Abortable && !~p)
                {
                    // Note: Throws away progress already made traversing the tree
                    return ~std::uint_least32_t(0); // error flag
                }
                cur = (unsigned(cur) << 1) | unsigned(bool(p));
            #ifdef DEFL_DO_HUFF_STATS
                if(len > maxlen)
                {
                    maxlen = len;
                    std::fprintf(stderr, "maxlen access: %d (%d)\n", maxlen, (int)tree.Get(0 + len));
                }
            #endif
                auto v = tree.Get(0 + len++);
                sum += v;
                cur -= v;
            } while(cur >= 0);
            return tree.Get(15 + sum + cur);
        }
    };

    template<bool Backtrackable>
    struct DeflateState: public DeflateBitCache
    {
        std::uint_least8_t lencode = 0, num = 0; // used in DynTreeFunc

        // Lengths are in 0..15 range.
        RandomAccessArray<USE_BITARRAY_FOR_LENGTHS, 288, CeilLog2<16>> Lengths;     // 144 bytes
        // Length tree
        //   Values up to 288 in indexes 0-14.   (Table)  (255 is max observed in wild)
        //   Values up to 287 in indexes 15-302. (Trans)
        RandomAccessArray<USE_BITARRAY_FOR_HUFFNODES, 15+288, CeilLog2<289>> ltree; // 341->344 bytes
        // Distance tree
        //   Values up to 32 in indexes 0-14.  (Table)
        //   Values up to 31 in indexes 15-46. (Trans)
        RandomAccessArray<USE_BITARRAY_FOR_HUFFNODES, 15+32, CeilLog2<33>> dtree;   // 36->40 bytes

        RandomAccessArray<USE_BITARRAY_FOR_HUFFNODES, 15+32, CeilLog2<33>>& lltree = dtree;

        // Theoretical minimum memory use:
        //   (15*log2(289) + 288*log2(288))/8 = 309.45 bytes for ltree
        //   (15*log2(33)  + 32 *log2(32))/8  =  29.46 bytes for dtree
        //                                      144.00 bytes for lengths
        //                                total 482.91 bytes

        template<bool Abortable, typename InputFunctor, typename BacktrackFunctor>
        auto DynTreeFunc(InputFunctor&& input, std::uint_fast16_t length, BacktrackFunctor&& /*backtrack*/,
                         bool
                         #ifdef DO_DEFDB_DUMPING
                             dists
                         #endif
                         )
        {
            Lengths = {}; // clear at least length nibbles; easiest to clear it all
            bool error = false;
            for(std::uint_fast16_t code = 0; ; )
            {
                #ifdef DO_DEFDB_DUMPING
                unsigned bits_before=bitcounter;
                #endif
                if(!num)
                {
                    auto p = HuffRead<Abortable>(std::forward<InputFunctor>(input), lltree);
                    if(Abortable && !~p) { error = true; goto done; }
                    std::uint_least8_t what = p; // 0-18

                    if(!(what & 16))    { lencode = what * 0x11u;           what = 0x01; } // 1 times (what < 16) (use what, set prev)
                    else if(what < 17)  { lencode = (lencode >> 4) * 0x11u; what = 0x23; } // 3..6 (use prev)
                    else if(what == 17) { lencode = 0;                      what = 0x33; } // 3..10   (use 0, set prev)
                    else                { lencode = 0;                      what = 0x7B; } // 11..138 (use 0, set prev)

                    p = GetBits<Abortable>(std::forward<InputFunctor>(input), what >> 4); // 0, 2, 3 or 7 bits
                    #ifdef DO_DEFDB_DUMPING
                    if(what>>4)
                    {
                        char tmp[64]="[_]"; sprintf(tmp, "[%d]", int(bitcounter-bits_before));
                        fprintf(stderr, "%4s %cREP (%d times)\n", tmp, (lencode&0xF)?'L':'Z', p+(what&0xF));
                    }
                    #endif

                    if(Abortable && !~p) { error = true; goto done; }
                    num = p + (what & 0xF); // 1..138
                }

                #ifdef DO_DEFDB_DUMPING
                bool rep=num>1;
                #endif
                do {
                    #ifdef DO_DEFDB_DUMPING
                    char tmp[64]="[_]"; if(!rep) sprintf(tmp, "[%d]", int(bitcounter-bits_before));
                    if(code == 0x100)
                        fprintf(stderr, "%4s EofB CL (val:%2d)\n", tmp, int(lencode&0xF));
                    else if(dists)
                        fprintf(stderr, "%4s d_%02d CL (val:%2d)\n", tmp, int(code), int(lencode&0xF));
                    else if(code > 0x100)
                        fprintf(stderr, "%4s l_%02d CL (val:%2d)\n", tmp, int(code- 0x101), int(lencode&0xF));
                    else
                        fprintf(stderr, "%4s 0x%02X CL (val:%2d)\n", tmp, (int)code, int(lencode&0xF));
                    #endif

                    --num;
                    Lengths.QSet(code++, lencode & 0xF);
                    if(code == length) { goto done; }
                } while(num > 0);
            }
         done:;
            return [this,error](unsigned index) -> std::conditional_t<Abortable, int, unsigned char>
                   {
                       if(Abortable && error) return -1;
                       return Lengths.Get(index);
                   };
        }
    };

    template<>
    struct DeflateState<true>: public DeflateBitCache
    {
        // Length tree
        //   Values up to 288 in indexes 0-14.   (Table)  (255 is max observed in wild)
        //   Values up to 287 in indexes 15-302. (Trans)
        RandomAccessArray<USE_BITARRAY_FOR_HUFFNODES, 15+288, CeilLog2<289>> ltree; // 341->344 bytes

        // Distance tree
        //   Values up to 32 in indexes 0-14.  (Table)
        //   Values up to 31 in indexes 15-46. (Trans)
        RandomAccessArray<USE_BITARRAY_FOR_HUFFNODES, 15+32, CeilLog2<33>> dtree;   // 36->40 bytes

        // Length-lengths tree
        //   Values up to 19 in indexes 0-14.  (Table) (13 is max observed in wild)
        //   Values up to 18 in indexes 15-33. (Trans)
        RandomAccessArray<USE_BITARRAY_FOR_HUFFNODES, 15+19, CeilLog2<20>> lltree;  // 22->24 bytes

        // Theoretical minimum memory use:
        //   (15*log2(289) + 288*log2(288))/8 = 309.45 bytes for ltree
        //   (15*log2(33)  + 32 *log2(32))/8  =  29.46 bytes for dtree
        //   (15*log2(20)  + 19 *log2(19))/8  =  18.19 bytes for lltree
        //                                total 357.10 bytes

        std::uint_least8_t lencode, num; // used in DynTreeFunc
        std::uint_least8_t checkpoint_lencode, checkpoint_num;
        std::uint_least8_t checkpoint_BitCache, checkpoint_BitCount;

        template<bool Abortable, typename InputFunctor, typename BacktrackFunctor>
        auto DynTreeFunc(InputFunctor&& input, std::uint_fast16_t /*length*/, BacktrackFunctor&& backtrack,
                         bool
                         #ifdef DO_DEFDB_DUMPING
                             dists
                         #endif
                         )
        {
            // Create checkpoint
            checkpoint_lencode  = 0;
            checkpoint_num      = 0;
            checkpoint_BitCache = BitCache;
            checkpoint_BitCount = BitCount;
            backtrack(false);

            return [this,&input,&backtrack](unsigned index) -> std::conditional_t<Abortable, int, unsigned char>
            {
                if(index == 0)
                {
                    // Restore checkpoint
                    lencode  = checkpoint_lencode;
                    num      = checkpoint_num;
                    BitCache = checkpoint_BitCache;
                    BitCount = checkpoint_BitCount;
                    backtrack(true);
                }

                if(Abortable && (num==0xFF)) return -1;

                if(!num)
                {
                    auto p = HuffRead<Abortable>(std::forward<InputFunctor>(input), lltree);
                    if(Abortable && !~p) { num = 0xFF; return -1; } // If p== ~uint64_t()
                    std::uint_least8_t what = p; // 0-18

                    if(!(what & 16))    { lencode = what * 0x11u;           what = 0x01; } // 1 times (what < 16) (use what, set prev)
                    else if(what < 17)  { lencode = (lencode >> 4) * 0x11u; what = 0x23; } // 3..6 (use prev)
                    else if(what == 17) { lencode = 0;                      what = 0x33; } // 3..10   (use 0, set prev)
                    else                { lencode = 0;                      what = 0x7B; } // 11..138 (use 0, set prev)

                    p = GetBits<Abortable>(std::forward<InputFunctor>(input), what >> 4); // 0, 2, 3 or 7 bits

                    if(Abortable && !~p) { num = 0xFF; return -1; } // If p== ~uint64_t()
                    num = p + (what & 0xF); // 1..138
                }
                --num;
                return (lencode & 0xF);
            };
        }
    };

    struct DeflateWindow
    {
        unsigned char Data[gunzip_ns::MAX_WINDOW_SIZE];
        SmallestType<CeilLog2<gunzip_ns::MAX_WINDOW_SIZE>> Head = 0;
    };

    #ifdef DEFLATE_ALLOCATION_STATIC
    template<typename ObjectType>
    ObjectType& GetStaticObj()
    {
        static thread_local ObjectType obj;
        obj.~ObjectType();
        new(&obj) ObjectType();
        return obj;
    }
    #endif

    /* Values of Abortable:
     *   Input abortable  = &1
     *   Output abortable = &2
     *   Resumable        = &4
     *
     *   Input abortable    Output abortable   Resumable     Value
     *                no                  no          no     0
     *               yes                  no          no     1
     *                no                 yes          no     2
     *               yes                 yes          no     3
     *                                                       4 = invalid
     *               yes                  no         yes     5
     *                no                 yes         yes     6
     *               yes                 yes         yes     7
     */
    template<unsigned char Abortable,
             typename InputFunctor, typename OutputFunctor, typename WindowFunctor,
             typename BacktrackFunctor>
    int Gunzip(InputFunctor&& input,
               OutputFunctor&& output,
               WindowFunctor&& outputcopy,
               BacktrackFunctor&& backtrack)
    {
        using namespace gunzip_ns;

        typedef DeflateState<!std::is_same_v<remove_cvref_t<BacktrackFunctor>,dummy>> StateType;
#ifdef DEFLATE_ALLOCATION_AUTOMATIC
        StateType state;
#elif defined(DEFLATE_ALLOCATION_STATIC)
        auto& state = gunzip_ns::GetStaticObj<StateType>();
#elif defined(DEFLATE_ALLOCATION_DYNAMIC)
        std::unique_ptr<StateType> stateptr(new StateType);
        auto& state = *stateptr;
#endif

        // The following routines are macros rather than e.g. lambda functions,
        // in order to make them inlined in the function structure, and breakable/resumable.
	#define CONCAT(a, b) a##b

        // Bit-by-bit input routine
        #define DummyGetBits_(line,numbits) do { \
            auto CONCAT(pd,line) = state.template GetBits<bool(Abortable&Flag_InputAbortable)>(std::forward<InputFunctor>(input), numbits); \
            if((Abortable & Flag_InputAbortable) && !~CONCAT(pd,line)) return -2; \
        } while(0)
        #define DummyGetBits(numbits) DummyGetBits_(__LINE__, numbits)

        #define GetBits_(line,numbits, target) \
            auto CONCAT(pb,line) = state.template GetBits<bool(Abortable&Flag_InputAbortable)>(std::forward<InputFunctor>(input), numbits); \
            if((Abortable & Flag_InputAbortable) && !~CONCAT(pb,line)) return -2; \
            target = CONCAT(pb,line)
        #define GetBits(numbits, target) GetBits_(__LINE__, numbits, target)

        // Huffman tree read routine.
        #define HuffRead_(line, tree, target) \
            auto CONCAT(ph,line) = state.template HuffRead<bool(Abortable&Flag_InputAbortable)>(std::forward<InputFunctor>(input), tree); \
            if((Abortable & Flag_InputAbortable) && !~CONCAT(ph,line)) return -2; \
            target = CONCAT(ph,line)
        #define HuffRead(tree, target) HuffRead_(__LINE__, tree, target)

        #define Fail_If(condition) do { \
            /*assert(!(condition));*/ \
            if(condition) return -1; \
        } while(0)

        // Read stream header
        GetBits(16, std::uint_least16_t header);
        // ^ Read deflate header: method[4] ; winsize[4] ; checksum[8]
        if(header == 0x8B1F) // Is it actually a gzip header?
        {
            // Get format identifier, flags, MTIME, XFL and OS
            GetBits(64, header); Fail_If((header & 0xFF) != 8); // Format identifier should be 8
            if(header&0x0400) // Skip extra fields as indicated by FEXTRA
                { GetBits(16, std::uint_fast16_t q); DummyGetBits(8*q); }
            if(header&0x0800) for(;;) { GetBits(8, bool q); if(!q) break; } // NAME: Skip filename if FNAME was present
            if(header&0x1000) for(;;) { GetBits(8, bool q); if(!q) break; } // COMMENT: Skip comment if FCOMMENT was present
            if(header&0x0200) { DummyGetBits(16); }      // HCRC: Skip FCRC if was present
            outputcopy(0, 32768u); // GZIP always uses 32k window
        }
        else // No. Deflate header?
        {
            Fail_If((header & 0x208F) != 0x0008 || ((((header<<8)+(header>>8))&0xFFFF)%31) != 0);
            outputcopy(0, 256 << ((header >> 4) & 0xF)); // Preset dictionary (0x2000) is not supported
        }

        // Read compressed blocks
        for(;;)
        {
            GetBits(3, header);
            //fprintf(stderr, "header=%d\n", header);
            if(header & 4) // Dynamic block
            {
                Fail_If(header & 2);
                std::uint_least16_t nlen_ndist_ncode;
                GetBits(14, nlen_ndist_ncode);

                #define nlen  (((nlen_ndist_ncode >> 0u) & 0x1Fu) + 257u) // 257..288
                #define ndist (((nlen_ndist_ncode >> 5u) & 0x1Fu) + 1u)   // 1..32


                std::uint_least8_t ncode = ((nlen_ndist_ncode >> 10u) + 4u); // 4..19
                {std::uint_fast64_t lenlens; GetBits(ncode*3, lenlens);      // Max: 19*3 = 57 bits
                #ifdef DO_DEFDB_DUMPING
                fprintf(stderr, " [5] HLIT%5d (val:%d)\n [5] HDIST%4d (val:%d)\n [4] HCLEN%4d (val:%d)\n",
                    nlen,nlen-257, ndist,ndist-1, ncode,ncode-4);
                for(unsigned a=0; a<19; ++a)
                    for(unsigned b=0; b<19; ++b)
                        if(rshift(b) == 3*a)
                        {
                            if(a < ncode)
                                fprintf(stderr, " [3]%3d CLL (val: %d)\n", b, int((lenlens >> rshift(b)) & 7));
                            else
                                fprintf(stderr, " [_]%3d CLL (val: %d)\n", b, int((lenlens >> rshift(b)) & 7));
                        }
                #endif

                auto lltree_fun = [=](unsigned a) -> unsigned char { return (lenlens >> rshift(a)) & 7; };
                while(CreateHuffmanTree<bool(Abortable&Flag_InputAbortable)>("Len Lengths", state.lltree, 19, lltree_fun)) { return -2; }}

                {auto ltree_fun = state.template DynTreeFunc<bool(Abortable&Flag_InputAbortable)>(std::forward<InputFunctor>(input), nlen, std::forward<BacktrackFunctor>(backtrack), false);
                while(CreateHuffmanTree<bool(Abortable&Flag_InputAbortable)>("Dyn Lengths", state.ltree, nlen, ltree_fun)) { return -2; }}

                {auto dtree_fun = state.template DynTreeFunc<bool(Abortable&Flag_InputAbortable)>(std::forward<InputFunctor>(input), ndist, std::forward<BacktrackFunctor>(backtrack), true);
                while(CreateHuffmanTree<bool(Abortable&Flag_InputAbortable)>("Dyn Dists",   state.dtree, ndist, dtree_fun)) { return -2; }}

                #undef nlen
                #undef ndist
            }
            else           // Fixed block
            {
                if(header < 2) // Copy stored block data
                {
                    DummyGetBits(state.BitCount%8); // Go to byte boundary (discard a few bits)
                    GetBits(32, std::uint_least32_t a);
                    Fail_If(((a ^ (a >> 16)) & 0xFFFF) != 0xFFFF);
                    #ifdef DO_DEFDB_DUMPING
                    fprintf(stderr, "raw block of %d bytes (0x%X)\n", (unsigned short)a, a);
                    #endif
                    // Note: It is valid for (lower 16 bits of) "a" to be 0 here.
                    // It is sometimes used for aligning the stream to byte boundary.
                    while(a-- & 0xFFFF)
                    {
                        GetBits(8, unsigned char octet);
                        while(OutputHelper<bool(Abortable&Flag_OutputAbortable)>::output(output, octet)) { return -3; }
                    }
                    goto skipdef;
                }

                unsigned char (*ltree_fun)(unsigned) = [](unsigned n)->unsigned char{return (n<0x90 || n>=0x118) ? 8u : (n<0x100 ? 9u : 7u); };
                unsigned char (*dtree_fun)(unsigned) = [](unsigned  )->unsigned char{return 5u;};
                while(CreateHuffmanTree<false>("Stat Lengths", state.ltree, 288, ltree_fun)) { return -2; }
                while(CreateHuffmanTree<false>("Stat Dists",   state.dtree, 32,  dtree_fun)) { return -2; }
            }
            // Do actual deflating.
            for(;;)
            {
                #ifdef DO_DEFDB_DUMPING
                unsigned a=bitcounter;
                #endif
                HuffRead(state.ltree, std::uint_least16_t lencode); // 0..287
                if(!(lencode & -256)) // 0..255: literal byte
                {
                    #ifdef DO_DEFDB_DUMPING
                    {char tmp[64];sprintf(tmp,"[%d]",bitcounter-a); fprintf(stderr, "%4s %02X\n", tmp, lencode);}
                    #endif
                    while(OutputHelper<bool(Abortable&Flag_OutputAbortable)>::output(output, lencode)) { return -3; }
                }
                else if(!(lencode & 0xFF)) break; // 256=end
                else // 257..287: length code for backwards reference
                {
                    GetBits(lbits(lencode), std::uint_least16_t length); length += lbase(lencode);
                    {HuffRead(state.dtree, std::uint_least8_t distcode); // Read distance code (0..31)
                    {GetBits(dbits(distcode), std::uint_least32_t offset); offset += dbase(distcode);
                    #ifdef DO_DEFDB_DUMPING
                    {char tmp[64];sprintf(tmp,"[%d]",bitcounter-a); fprintf(stderr, "%4s (%d,%d)\n", tmp,length,offset);}
                    #endif
                    while(OutputHelper<bool(Abortable&Flag_OutputAbortable)>::outputcopy(outputcopy,length,offset)) { return -4; }}}
                }
            }
    skipdef:if(header & 1) break; // last block flag
        }
        // Note: after this, may come a checksum, and a trailer. Ignoring them.
        #undef GetBits
        #undef DummyGetBits
        #undef Fail_If
        #undef HuffRead
        return 0;
    }
}//ns


/*
`InputParams` may be one of the following sets of parameters:

* InputFunctor   input                                   `(5)` `(14)`
* InputIterator  begin                                   `(7)` `(14)`
* InputIterator  begin, InputIterator end                `(6)` `(14)`
* InputIterator  begin, SizeType length                  `(8)` `(14)`
* BidirectionalIterator begin, SizeType length           `(8)` `(15)`
* ForwardIterator       begin                            `(7)` `(14)`
* BidirectionalIterator begin                            `(7)` `(15)`
* RandomAccessIterator  begin                            `(7)` `(15)`
* ForwardIterator       begin, ForwardIterator       end `(6)` `(15)`
* BidirectionalIterator begin, BidirectionalIterator end `(6)` `(15)`
* RandomAccessIterator  begin, RandomAccessIterator  end `(6)` `(15)`

`OutputParams` may be one of the following sets of parameters:

* OutputFunctor        output                          `(1)` `(9)`
* OutputFunctor        output, WindowFunctor window    `(2)`
* OutputIterator       target                          `(9)`
* RandomAccessIterator target                                           `(10)`
* RandomAccessIterator target,   SizeType target_limit            `(3)` `(10)`
* RandomAccessIterator target,   RandomAccessIterator target_end  `(4)` `(10)`
*/

namespace gunzip_ns
{
    #ifdef DEFLATE_ALLOCATION_AUTOMATIC
        #define DeflDeclWindow gunzip_ns::DeflateWindow window;
    #elif defined(DEFLATE_ALLOCATION_STATIC)
        #define DeflDeclWindow auto& window = gunzip_ns::GetStaticObj<gunzip_ns::DeflateWindow>();
    #elif defined(DEFLATE_ALLOCATION_DYNAMIC)
        #define DeflDeclWindow std::unique_ptr<gunzip_ns::DeflateWindow> winptr(new gunzip_ns::DeflateWindow); \
                               auto& window = *winptr;
    #endif

    template<unsigned char code, typename I,typename O,typename C,typename B>
    auto DeflateDispatchFinal(I&& i, O&& o, C&& c, B&& b)
    {
        if constexpr(code & (Flag_TrackIn | Flag_TrackOut))
        {
            //fprintf(stderr, "both track flag\n");
            SizeTracker<DeflateTrackBothSize> tracker;
            return tracker(Gunzip<code & Flag_NoTrackFlagMask>
                (tracker.template ForwardInput(i), tracker.template ForwardOutput(o), tracker.template ForwardWindow(c), std::forward<B>(b)));
        }
        else if constexpr(code & Flag_TrackIn)
        {
            //fprintf(stderr, "in track flag\n");
            SizeTracker<DeflateTrackInSize> tracker;
            return tracker(Gunzip<code & Flag_NoTrackFlagMask>
                (tracker.template ForwardInput(i),std::forward<O>(o),std::forward<C>(c),std::forward<B>(b)));
        }
        else if constexpr(code & Flag_TrackOut)
        {
            //fprintf(stderr, "out track flag\n");
            SizeTracker<DeflateTrackOutSize> tracker;
            return tracker(Gunzip<code & Flag_NoTrackFlagMask>
                (std::forward<I>(i), tracker.template ForwardOutput(o), tracker.template ForwardWindow(c), std::forward<B>(b)));
        }
        else
        {
            //fprintf(stderr, "no track flag\n");
            return Gunzip<code & Flag_NoTrackFlagMask>(std::forward<I>(i),std::forward<O>(o),std::forward<C>(c),std::forward<B>(b));
        }
    }

    // One-parameter output dispatch:
    template<unsigned char code, typename BtFun, typename InFun, typename T1>
    auto DeflateOutputDispatch(BtFun&& bt, InFun&& infun, T1&& param1)
    {
        // Is param1 a random access iterator?
        if constexpr(is_random_iterator_v<T1>)
        {
            //fprintf(stderr, "random iterator\n");
            auto output     = [&](unsigned char l) { *param1 = l; ++param1; };
            auto outputcopy = [&](std::uint_least16_t length, std::uint_fast32_t offs)
            {
                /* length=0 means that offs is the size of the window. */
                for(; length--; ++param1) { *param1 = *(param1-offs); }
            };
            return DeflateDispatchFinal<code>(std::forward<InFun>(infun), output, outputcopy, std::forward<BtFun>(bt));
        }
        // Is param1 an output iterator?
        else if constexpr(is_output_iterator_v<T1>)
        {
            //fprintf(stderr, "output iterator\n");
            DeflDeclWindow
            auto output = [&](unsigned char l)
            {
                window.Data[window.Head++ % MAX_WINDOW_SIZE] = l;
                *param1 = l; ++param1;
            };
            auto outputcopy = [&](std::uint_least16_t length, std::uint_fast32_t offs)
            {
                /* length=0 means that offs is the size of the window. */
                for(; length>0; --length)
                {
                    unsigned char byte = window.Data[(window.Head - offs) % MAX_WINDOW_SIZE];
                    output(byte);
                }
                return false;
            };
            return DeflateDispatchFinal<code>(std::forward<InFun>(infun), output, outputcopy, std::forward<BtFun>(bt));
        }
        // param1 must be an output functor, then.
        else if constexpr(is_output_functor_v<T1>)
        {
            //fprintf(stderr, "output functor\n");
            DeflDeclWindow
            auto output = [&](unsigned char l)
            {
                window.Data[window.Head++ % MAX_WINDOW_SIZE] = l;
                return param1(l);
            };
            auto outputcopy = [&](std::uint_least16_t length, std::uint_fast32_t offs)
            {
                /* length=0 means that offs is the size of the window. */
                for(; length>0; --length)
                {
                    unsigned char byte = window.Data[(window.Head - offs) % MAX_WINDOW_SIZE];
                    if(OutputHelper<DeflAbortable_OutFun<T1>>::output(output, byte))
                        break;
                }
                return length;
            };
            return DeflateDispatchFinal
                <code | (DeflAbortable_OutFun<T1> ? Flag_OutputAbortable : 0)>
                (std::forward<InFun>(infun), output, outputcopy, std::forward<BtFun>(bt));
        }
        else
        {
            //fprintf(stderr, "unreached code 1\n");
            static_assert(code==0xFF, "Deflate: Unknown output parameter type");
        }
    }

    // Two-parameter output dispatch:
    template<unsigned char code, typename BtFun, typename InFun, typename T1, typename T2>
    auto DeflateOutputDispatch(BtFun&& bt, InFun&& infun, T1&& param1, T2&& param2)
    {
        if constexpr(std::is_same_v<remove_cvref_t<T2>, DeflateTrackNoSize>)
        {
            //fprintf(stderr, "no track flag...\n");
            return DeflateOutputDispatch<code> (std::forward<BtFun>(bt), std::forward<InFun>(infun), std::forward<T1>(param1));
        }
        else if constexpr(std::is_same_v<remove_cvref_t<T2>, DeflateTrackInSize>)
        {
            //fprintf(stderr, "in track flag...\n");
            return DeflateOutputDispatch<code | Flag_TrackIn> (std::forward<BtFun>(bt), std::forward<InFun>(infun), std::forward<T1>(param1));
        }
        else if constexpr(std::is_same_v<remove_cvref_t<T2>, DeflateTrackOutSize>)
        {
            //fprintf(stderr, "out track flag...\n");
            return DeflateOutputDispatch<code | Flag_TrackOut> (std::forward<BtFun>(bt), std::forward<InFun>(infun), std::forward<T1>(param1));
        }
        else if constexpr(std::is_same_v<remove_cvref_t<T2>, DeflateTrackBothSize>)
        {
            //fprintf(stderr, "both track flag...\n");
            return DeflateOutputDispatch<code | Flag_TrackIn | Flag_TrackOut> (std::forward<BtFun>(bt), std::forward<InFun>(infun), std::forward<T1>(param1));
        }
        // Are param1 and param2 both random access iterators?
        else if constexpr(std::is_same_v<T1,T2> && is_random_iterator_v<T1>)
        {
            //fprintf(stderr, "random iterator + random iterator\n");
            auto output = [&](unsigned char l)
            {
                if(param1 == param2) return true;
                *param1 = l; ++param1;
                return false;
            };
            auto outputcopy = [&](std::uint_least16_t length, std::uint_fast32_t offs)
            {
                /* length=0 means that offs is the size of the window. */
                for(; length > 0 && !(param1 == param2); --length, ++param1)
                {
                    *param1 = *(param1 - offs);
                }
                return length;
            };
            return DeflateDispatchFinal<code | Flag_OutputAbortable>(std::forward<InFun>(infun), output, outputcopy, std::forward<BtFun>(bt));
        }
        // Is param1 a random access iterator and param2 a size?
        else if constexpr(is_size_type_v<T2> && is_random_iterator_v<T1>)
        {
            //fprintf(stderr, "random iterator + size\n");
            typename std::iterator_traits<remove_cvref_t<T1>>::difference_type used{}, cap=param2;
            auto output = [&](unsigned char l)
            {
                if(used >= cap) return true;
                param1[used] = l; ++used;
                return false;
            };
            auto outputcopy = [&](std::uint_least16_t length, std::uint_fast32_t offs)
            {
                /* length=0 means that offs is the size of the window. */
                for(; length > 0 && used < cap; ++used, --length)
                {
                    param1[used] = param1[used - offs];
                }
                return length;
            };
            return DeflateDispatchFinal<code | Flag_OutputAbortable>(std::forward<InFun>(infun), output, outputcopy, std::forward<BtFun>(bt));
        }
        // Then, param1 must be an output functor and param2 a window functor.
        else if constexpr(is_output_functor_v<T1> && is_window_functor_v<T2>)
        {
            //fprintf(stderr, "output functor + window functor\n");
            return DeflateDispatchFinal
                <code | ( (DeflAbortable_OutFun<T1> && DeflAbortable_WinFun<T2>) ? Flag_OutputAbortable : 0 ) >
                (std::forward<InFun>(infun), std::forward<T1>(param1), std::forward<T2>(param2), std::forward<BtFun>(bt));
        }
        else
        {
            //fprintf(stderr, "unreached code 2\n");
            static_assert(code==0xFF, "Deflate: Unknown output parameter type");
        }
    }

    // Three-parameter output dispatch:
    template<unsigned char code, typename BtFun, typename InFun, typename T1, typename T2, typename T3>
    auto DeflateOutputDispatch(BtFun&& bt, InFun&& infun, T1&& p1, T2&& p2, T3)
    {
        if constexpr(std::is_same_v<remove_cvref_t<T3>, DeflateTrackNoSize>)
        {
            //fprintf(stderr, "no track flag...\n");
            return DeflateOutputDispatch<code> (std::forward<BtFun>(bt), std::forward<InFun>(infun), std::forward<T1>(p1), std::forward<T2>(p2));
        }
        else if constexpr(std::is_same_v<remove_cvref_t<T3>, DeflateTrackInSize>)
        {
            //fprintf(stderr, "in track flag...\n");
            return DeflateOutputDispatch<code | Flag_TrackIn> (std::forward<BtFun>(bt), std::forward<InFun>(infun), std::forward<T1>(p1), std::forward<T2>(p2));
        }
        else if constexpr(std::is_same_v<remove_cvref_t<T3>, DeflateTrackOutSize>)
        {
            //fprintf(stderr, "out track flag...\n");
            return DeflateOutputDispatch<code | Flag_TrackOut> (std::forward<BtFun>(bt), std::forward<InFun>(infun), std::forward<T1>(p1), std::forward<T2>(p2));
        }
        else if constexpr(std::is_same_v<remove_cvref_t<T3>, DeflateTrackBothSize>)
        {
            //fprintf(stderr, "both track flag...\n");
            return DeflateOutputDispatch<code | Flag_TrackIn | Flag_TrackOut> (std::forward<BtFun>(bt), std::forward<InFun>(infun), std::forward<T1>(p1), std::forward<T2>(p2));
        }
        else
        {
            //fprintf(stderr, "unreached code 3\n");
            static_assert(code==0xFF, "Deflate: Mismatched parameters. Expected last parameter to be a DeflateTrack option.");
        }
    }

    // One or two parameter input dispatch:
    template<unsigned char code, typename BtFun, typename T1, typename T2, typename... T>
    auto DeflateInputDispatch(BtFun&& bt, T1&& param1, T2&& param2, T&&... args)
    {
        using namespace gunzip_ns;
        // Are param1 and param2 an input iterator pair?
        if constexpr(std::is_same_v<T1, T2> && is_input_iterator_v<T1>)
        {
            //fprintf(stderr, "input iterator + input iterator\n");
            auto inputfun = [&]() -> std::common_type_t<int, decltype(*param1)>
                            { if(param1 == param2) { return -1; } int r = *param1; ++param1; return r; };
            return DeflateOutputDispatch<code|Flag_InputAbortable>(std::forward<BtFun>(bt),  inputfun, std::forward<T>(args)...);
        }
        // Are param1 and param2 a pair of bidirectional input iterators (forward, bidir, random)?
        else if constexpr(std::is_same_v<T1, T2> && is_bidir_input_v<T1>)
        {
            //fprintf(stderr, "bidir input + bidir input\n");
            remove_cvref_t<T1> saved{param1};
            auto btfun    = [&](bool act) { if(act) param1 = saved; else saved = std::move(param1); };
            auto inputfun = [&]() -> std::common_type_t<int, decltype(*param1)>
                            { if(param1 == param2) { return -1; } int r = *param1; ++param1; return r; };
            return DeflateOutputDispatch<code|Flag_InputAbortable>(btfun, inputfun, std::forward<T>(args)...);
        }
        // Is param1 an input iterator and param2 a size?
        else if constexpr(is_size_type_v<T2> && is_input_iterator_v<T1>)
        {
            //fprintf(stderr, "input iterator + size\n");
            typename std::iterator_traits<remove_cvref_t<T1>>::difference_type remain{param2};
            auto inputfun = [&]() -> std::common_type_t<int, decltype(*param1)>
                            { if(!remain) return -1; --remain; int r = *param1; ++param1; return r; };
            return DeflateOutputDispatch<code|Flag_InputAbortable>(std::forward<BtFun>(bt),  inputfun, std::forward<T>(args)...);
        }
        // Is param1 a bidirectional input iterator (forward, bidir, random) and param2 a size?
        else if constexpr(is_size_type_v<T2> && is_bidir_input_v<T1>)
        {
            //fprintf(stderr, "bidir input + size\n");
            typename std::iterator_traits<remove_cvref_t<T1>>::difference_type remain{param2}, savestate{};
            auto btfun    = [&](bool act) { if(act) { param1 -= (savestate-remain); remain = savestate; } else savestate = remain; };
            auto inputfun = [&]() -> std::common_type_t<int, decltype(*param1)>
                            { if(!remain) return -1; --remain; int r = *param1; ++param1; return r; };
            return DeflateOutputDispatch<code|Flag_InputAbortable>(btfun, inputfun, std::forward<T>(args)...);
        }
        // Is param1 an input iterator?
        else if constexpr(is_input_iterator_v<T1>)
        {
            //fprintf(stderr, "input iterator\n");
            auto inputfun = [&]() -> std::remove_cv_t<decltype(*param1)> { auto r = *param1; ++param1; return r; };
            return DeflateOutputDispatch
                <code | ( is_abortable_input_type_v<remove_cvref_t<decltype(*param1)>> ? Flag_InputAbortable : 0 ) >
                (std::forward<BtFun>(bt),  inputfun, std::forward<T2>(param2), std::forward<T>(args)...);
        }
        // Is param1 a bidirectional input iterator (forward, bidir, random)?
        else if constexpr(is_bidir_input_v<T1>)
        {
            //fprintf(stderr, "bidir input\n");
            remove_cvref_t<T1> saved{param1};
            auto btfun    = [&](bool act) { if(act) param1 = saved; else saved = std::move(param1); };
            auto inputfun = [&]() -> std::remove_cv_t<decltype(*param1)> { auto r = *param1; ++param1; return r; };
            return DeflateOutputDispatch<code>(btfun, inputfun, std::forward<T2>(param2), std::forward<T>(args)...);
        }
        // param1 must be an input functor, then. Let's move on to param2 testing!
        else if constexpr(is_input_functor_v<T1>)
        {
            //fprintf(stderr, "input functor\n");
            return DeflateOutputDispatch
                <code | ( DeflAbortable_InFun<T1> ? Flag_InputAbortable : 0 ) >
                (std::forward<BtFun>(bt),  std::forward<T1>(param1), std::forward<T2>(param2), std::forward<T>(args)...);
        }
        else
        {
            //fprintf(stderr, "unreached code 0\n");
            static_assert(code==0xFF, "Deflate: Mismatched parameters. Expected something for an input.");
        }
    }
    #undef DeflDeclWindow
}


template<typename... T>
auto Deflate(T&&... args)
{
    return gunzip_ns::DeflateInputDispatch<0>(gunzip_ns::dummy{}, std::forward<T>(args)...);
}

#endif /* #ifndef DOXYGEN_SHOULD_SKIP_THIS */

Lines 1-6 Link Here

(-)a/src/CMakeLists.txt (+1 lines)
1	# vim:ts=4:sw=4:expandtab:autoindent:	1	# vim:ts=4:sw=4:expandtab:autoindent:
2		2
3	include_directories(	3	include_directories(
		4	${PROJECT_SOURCE_DIR}/TinyDeflate
4	${PROJECT_SOURCE_DIR}/filesystem	5	${PROJECT_SOURCE_DIR}/filesystem
5	${PROJECT_SOURCE_DIR}/libmd5	6	${PROJECT_SOURCE_DIR}/libmd5
6	${PROJECT_SOURCE_DIR}/liblodepng	7	${PROJECT_SOURCE_DIR}/liblodepng

Lines 16-21 Link Here

(-)a/src/dotrunner.cpp (-27 / +125 lines)
16	#include <cassert>	16	#include <cassert>
17	#include <cmath>	17	#include <cmath>
18		18
		19	#ifdef _MSC_VER
		20	#pragma warning( push )
		21	#pragma warning( disable : 4242 )
		22	#pragma warning( disable : 4244 )
		23	#pragma warning( disable : 4996 )
		24	#endif
		25	#include <gunzip.hh>
		26	#ifdef _MSC_VER
		27	#pragma warning( pop )
		28	#endif
		29
		30
19	#include "dotrunner.h"	31	#include "dotrunner.h"
20	#include "util.h"	32	#include "util.h"
21	#include "portable.h"	33	#include "portable.h"
Lines 31-36 Link Here
31	#define MAX_LATEX_GRAPH_INCH 150	43	#define MAX_LATEX_GRAPH_INCH 150
32	#define MAX_LATEX_GRAPH_SIZE (MAX_LATEX_GRAPH_INCH * 72)	44	#define MAX_LATEX_GRAPH_SIZE (MAX_LATEX_GRAPH_INCH * 72)
33		45
		46	//#define DBG(x) printf x
		47	#define DBG(x) do {} while(0)
		48
34	//-----------------------------------------------------------------------------------------	49	//-----------------------------------------------------------------------------------------
35		50
36	// since dot silently reproduces the input file when it does not	51	// since dot silently reproduces the input file when it does not
Lines 108-144 static bool resetPDFSize(const int width,const int height, const QCString &base) Link Here
108		123
109	bool DotRunner::readBoundingBox(const QCString &fileName,int width,int height,bool isEps)	124	bool DotRunner::readBoundingBox(const QCString &fileName,int width,int height,bool isEps)
110	{	125	{
111	const char *bb = isEps ? "%%PageBoundingBox:" : "/MediaBox [";	126	std::ifstream f = Portable::openInputStream(fileName);
112	size_t bblen = strlen(bb);	127	if (!f.is_open())
113	FILE *f = Portable::fopen(fileName,"rb");
114	if (!f)
115	{	128	{
116	//printf("readBoundingBox: could not open %s\n",fileName);	129	err("Failed to open file %s for extracting bounding box\n",qPrint(fileName));
117	return FALSE;	130	return false;
118	}	131	}
119	const int maxLineLen=1024;	132
120	char buf[maxLineLen];	133	// read file contents into string 'contents'
121	while (fgets(buf,maxLineLen,f)!=NULL)	134	std::stringstream buffer;
		135	buffer << f.rdbuf();
		136	std::string contents = buffer.str();
		137
		138	// start of bounding box marker we are looking for
		139	const std::string boundingBox = isEps ? "%%PageBoundingBox:" : "/MediaBox [";
		140
		141	// helper routine to extract the bounding boxes width and height
		142	auto extractBoundingBox = [&fileName,&boundingBox,&width,&height](const char *s) -> bool
122	{	143	{
123	const char *p = strstr(buf,bb);	144	int x,y;
124	if (p) // found PageBoundingBox or /MediaBox string	145	double w,h;
125	{	146	if (sscanf(s+boundingBox.length(),"%d %d %lf %lf",&x,&y,&w,&h)==4)
126	int x,y;	147	{
127	double w,h;	148	*width = static_cast<int>(std::ceil(w));
128	fclose(f);	149	*height = static_cast<int>(std::ceil(h));
129	if (sscanf(p+bblen,"%d %d %lf %lf",&x,&y,&w,&h)!=4)	150	return true;
130	{	151	}
131	//printf("readBoundingBox sscanf fail\n");	152	err("Failed to extract bounding box from generated diagram file %s\n",qPrint(fileName));
132	return FALSE;	153	return false;
133	}	154	};
134	*width = static_cast<int>(std::ceil(w));	155
135	*height = static_cast<int>(std::ceil(h));	156	// compressed segment start and end markers
136	return TRUE;	157	const std::string streamStart = "stream\n";
137	}	158	const std::string streamEnd = "\nendstream";
		159
		160	auto detectDeflateStreamStart = [&streamStart](const char *s)
		161	{
		162	size_t len = streamStart.length();
		163	bool streamOK = strncmp(s,streamStart.c_str(),len)==0;
		164	if (streamOK) // ASCII marker matches, check stream header bytes as well
		165	{
		166	unsigned short header1 = static_cast<unsigned char>(s[len])<<8; // CMF byte
		167	if (header1) // not end of string
		168	{
		169	unsigned short header = (static_cast<unsigned char>(s[len+1])) \| header1; // FLG byte
		170	// check for correct header (see https://www.rfc-editor.org/rfc/rfc1950)
		171	return ((header&0x8F20)==0x0800) && (header%31)==0;
		172	}
		173	}
		174	return false;
		175	};
		176
		177	const size_t l = contents.length();
		178	size_t i=0;
		179	while (i<l)
		180	{
		181	if (!isEps && contents[i]=='s' && detectDeflateStreamStart(&contents[i]))
		182	{ // compressed stream start
		183	int col=17;
		184	i+=streamStart.length();
		185	const size_t start=i;
		186	DBG(("---- start stream at offset %08x\n",(int)i));
		187	while (i<l)
		188	{
		189	if (contents[i]=='\n' && strncmp(&contents[i],streamEnd.c_str(),streamEnd.length())==0)
		190	{ // compressed block found in range [start..i]
		191	DBG(("\n---- end stream at offset %08x\n",(int)i));
		192	// decompress it into decompressBuf
		193	std::vector<char> decompressBuf;
		194	const char *source = &contents[start];
		195	const size_t sourceLen = i-start;
		196	size_t sourcePos = 0;
		197	decompressBuf.reserve(sourceLen*2);
		198	auto getter = [source,&sourcePos,sourceLen]() -> int {
		199	return sourcePos<sourceLen ? static_cast<unsigned char>(source[sourcePos++]) : EOF;
		200	};
		201	auto putter = [&decompressBuf](const char c) -> int {
		202	decompressBuf.push_back(c); return c;
		203	};
		204	Deflate(getter,putter);
		205	// convert decompression buffer to string
		206	std::string s(decompressBuf.begin(), decompressBuf.end());
		207	DBG(("decompressed_data=[[[\n%s\n]]]\n",s.c_str()));
		208	// search for bounding box marker
		209	const size_t idx = s.find(boundingBox);
		210	if (idx!=std::string::npos) // found bounding box in uncompressed data
		211	{
		212	return extractBoundingBox(s.c_str()+idx);
		213	}
		214	// continue searching after end stream marker
		215	i+=streamEnd.length();
		216	break;
		217	}
		218	else // compressed stream character
		219	{
		220	if (col>16) { col=0; DBG(("\n%08x: ",static_cast<int>(i))); }
		221	DBG(("%02x ",static_cast<unsigned char>(contents[i])));
		222	col++;
223	i++;
224	}
225	}
226	}
227	else if (((isEps && contents[i]=='%') \|\| (!isEps && contents[i]=='/')) &&
228	strncmp(&contents[i],boundingBox.c_str(),boundingBox.length())==0)
229	{ // uncompressed bounding box
230	return extractBoundingBox(&contents[i]);
231	}
232	else // uncompressed stream character
233	{
234	i++;
235	}
138	}	236	}
139	err("Failed to extract bounding box from generated diagram file %s\n",qPrint(fileName));	237	err("Failed to find bounding box in generated diagram file %s\n",qPrint(fileName));
140	fclose(f);	238	// nothing found
141	return FALSE;	239	return false;
142	}	240	}
143		241
144	//---------------------------------------------------------------------------------	242	//---------------------------------------------------------------------------------

Lines 11920-11927 void parseInput() Link Here

(-)a/src/doxygen.cpp (-2 lines)
11920	{	11920	{
11921	Portable::setenv("DOTFONTPATH",qPrint(curFontPath));	11921	Portable::setenv("DOTFONTPATH",qPrint(curFontPath));
11922	}	11922	}
11923	// issue 9319
11924	Portable::setenv("CAIRO_DEBUG_PDF","1");
11925	}	11923	}
11926		11924
11927		11925

Return to bug 884185

Line 0 Link Here

(-)a/TinyDeflate/README.md (+362 lines)
		1	# TinyDeflate
		2
		3	See https://github.com/bisqwit/TinyDeflate for the original version.
		4
		5	A deflate/gzip decompressor, as a C++17 template function,
		6	that requires minimal amount of memory to work.
		7
		8	Terms of use: Zlib
		9	Copyright © 2018 Joel Yliluoma
		10
		11	## Memory usage at aggressive settings (backtrackable input)
		12
		13	* 408 bytes of automatic storage for three huffman trees (384 elements, 5…9 bits each, 88 % space efficiency)
		14	* 24 bytes of temporary automatic storage while a huffman tree is being generated (15 elements, 9 bits each, 66 % space efficiency)
		15	* An assortment of automatic variables for various purposes (may be register variables, depending on the architecture and of the compiler wits)
		16	* ABI mandated alignment losses
		17
		18	Total: 408 bytes minimum, 432+N bytes maximum
		19
		20	Theoretical minimum at 100 % efficiency: 357.1 + 15.32 ≃ 373 bytes (not yet attained by this library).
		21
		22	## Memory usage at aggressive settings (non-backtrackable input)
		23
		24	* 144 bytes of automatic storage for length tables (288 elements, 4 bits each, 100 % space efficiency)
		25	* 384 bytes of automatic storage for two huffman trees (350 elements, 5…9 bits each, 88 % space efficiency)
		26	* 24 bytes of temporary automatic storage while a huffman tree is being generated (15 elements, 9 bits each, 66 % space efficiency)
		27	* An assortment of automatic variables for various purposes (may be register variables, depending on the architecture and of the compiler wits)
		28	* ABI mandated alignment losses
		29
		30	Total: 528 bytes minimum, 552+N bytes maximum
		31
		32	Theoretical minimum at 100 % efficiency: 144 + 338.9 + 15.32 ≃ 499 bytes (not yet attained by this library).
		33
		34	## Memory usage at default settings (backtrackable input)
		35
		36	* 687 bytes of automatic storage for three huffman trees (52 % space efficiency)
		37	* 30 bytes of temporary automatic storage while a huffman tree is being generated (53 % space efficiency)
		38	* An assortment of automatic variables for various purposes (may be register variables, depending on the architecture and of the compiler wits)
		39	* ABI mandated alignment losses
		40
		41	Total: 687 bytes minimum, 717+N bytes maximum
		42
		43	## Memory usage at default settings (non-backtrackable input)
		44
		45	* 288 bytes of automatic storage for length tables (50 % space efficiency)
		46	* 653 bytes of automatic storage for two huffman trees (52 % space efficiency)
		47	* 30 bytes of temporary automatic storage while a huffman tree is being generated (53 % space efficiency)
		48	* An assortment of automatic variables for various purposes (may be register variables, depending on the architecture and of the compiler wits)
		49	* ABI mandated alignment losses
		50
		51	Total: 941 bytes minimum, 971+N bytes maximum
		52
		53	## Tuning
		54
		55	To adjust the memory usage, there are three settings in gunzip.hh you can change:
		56
		57	\| Setting name \| 'false' memory use bytes \| 'true' memory use bytes \| 'true' performance impact
		58	\| ------------------------------------------- \| ---:\| ----:\|--------------
		59	\| `USE_BITARRAY_TEMPORARY_IN_HUFFMAN_CREATION` \| 30 \| 24 \| Negligible
		60	\| `USE_BITARRAY_FOR_LENGTHS` \| 288 or 0 \| 144 or 0 \| Noticeable
		61	\| `USE_BITARRAY_FOR_HUFFNODES` \| 653 or 687 \| 384 or 408 \| Significant
		62	\| Total \| 971 or 717 \| 552 or 432 \| _Plus alignment losses, callframes and spills_
		63
		64	In addition, if you neither decompress into a raw memory area nor supply your own window function,
65	32768 bytes of automatic storage is allocated for the look-behind window.
66
67	You can also change the memory allocation scheme:
68
69	\| `#define` name \| Meaning
70	\| --- \| ---
71	\| `DEFLATE_ALLOCATION_AUTOMATIC` \| Automatic allocation (usually stack)
72	\| `DEFLATE_ALLOCATION_STATIC` \| Static `thread_local` allocation (memory remains allocated throughout the program, and different threads have their own copy of the data). Note that this scheme excludes running multiple decompressions in parallel, unless you do it in different threads.
73	\| `DEFLATE_ALLOCATION_DYNAMIC` \| Storage duration is the same as with automatic allocation, but the `new` keyword is explicitly used (which usually means heap/bss allocation).
74
75	There is also a constant `MAX_WINDOW_SIZE`, which is 32768 by default,
76	but you can reduce it to use less memory for the automatically allocated
77	window in situations where one is allocated (see note 9 below).
78	Note that this value must not be smaller than the maximum backreference
79	distance used by your compressed data.
80
81	## Unrequirements
82
83	* No dynamic memory is allocated under any circumstances, unless your user-supplied functors do it, or you `#define DEFLATE_ALLOCATION_DYNAMIC`.
84	* Aside from assert() in assert.h and some template metaprogramming tools in type_traits, no standard library functions are used.
85	* No global variables.
86	* Compatible with -fno-exceptions -fno-rtti compilation.
87	* Option to compile without constant arrays.
88
89	## Rationale
90
91	* Embedded platforms (Arduino, STM32 etc).
92	* ROM hacking
93
94	## Caveats
95
96	* Decompressor only. Deflate and GZIP streams are supported.
97	* Slower than your average inflate function. The template uses densely bitpacked arrays, which require plenty of bit-shifting operations for every access.
98	* The code obviously performs best on 32-bit or 64-bit platforms. Platforms where 32-bit entities must be synthesized from a number of 8-bit entities are at a disadvantage.
99	* Decompressed data integrity is not verified. Any checksum fields are totally ignored.
100	* On most systems, automatic storage means ‘stack allocation’. Depending on your circumstances, you may want to change the memory allocation scheme. See the Tuning chapter for details.
101
102	## Definitions
103
104	```C++
105	struct DeflateTrackNoSize{};
106	struct DeflateTrackInSize{};
107	struct DeflateTrackOutSize{};
108	struct DeflateTrackBothSize{};
109
110	int/exit status/ Deflate(InputParams..., OutputParams..., DeflateTrackNoSize = {});
111
112	std::pair<int/exit status/, std::uint_fast64_t/number of input bytes consumed/>
113	Deflate(InputParams..., OutputParams..., DeflateTrackInSize); // (11)
114
115	std::pair<int/exit status/, std::uint_fast64_t/number of output bytes generated/>
116	Deflate(InputParams..., OutputParams..., DeflateTrackOutSize); // (12)
117
118	std::pair<int/exit status/, std::pair<std::uint_fast64_t/in size/, std::uint_fast64_t/out size/>>
119	Deflate(InputParams..., OutputParams..., DeflateTrackBothSize); // (13)
120
121	// A counter for sizes is only allocated if explicitly requested
122	// by using one of the former three tracking overloads.
123	```
124
125	`InputParams` may be one of the following sets of parameters:
126
127	* InputFunctor input `(5)` `(14)`
128	* InputIterator begin `(7)` `(14)`
129	* InputIterator begin, InputIterator end `(6)` `(14)`
130	* InputIterator begin, SizeType length `(8)` `(14)`
131	* BidirectionalIterator begin, SizeType length `(8)` `(15)`
132	* ForwardIterator begin `(7)` `(14)`
133	* BidirectionalIterator begin `(7)` `(15)`
134	* RandomAccessIterator begin `(7)` `(15)`
135	* ForwardIterator begin, ForwardIterator end `(6)` `(15)`
136	* BidirectionalIterator begin, BidirectionalIterator end `(6)` `(15)`
137	* RandomAccessIterator begin, RandomAccessIterator end `(6)` `(15)`
138
139	`OutputParams` may be one of the following sets of parameters:
140
141	* OutputFunctor output `(1)` `(9)`
142	* OutputFunctor output, WindowFunctor window `(2)`
143	* OutputIterator target `(9)`
144	* RandomAccessIterator target `(10)`
145	* RandomAccessIterator target, SizeType target_limit `(3)` `(10)`
146	* RandomAccessIterator target, RandomAccessIterator target_end `(4)` `(10)`
147
148
149	1) If the output functor (`output`) returns a `bool`, and the returned value is `true`, the decompression aborts with return value -3
150	without writing any more data.
151
152	2) If the output functor (`output`) returns a `bool`, and the returned value is `true`, the decompression aborts with return value -3
153	without writing any more data.
154	If the window function returns an integer type, and the returned value is other than 0, the decompression aborts with return value -4
155	without writing any more data.
156	If either the window function returns `void`, or the output functor does not return a `bool`, aborting on output-full will not be compiled.
157
158	3) If `target_limit` bytes have been written into `target` and the decompression is not yet complete, the decompression aborts with return value -3
159	without writing any more data.
160
161	4) If `target_begin == target_end`, the decompression aborts with return value -3
162	without writing any more data.
163
164	5) If the input functor (`input`) returns an integer type other than a `char`, `signed char`, or `unsigned char`,
165	and the returned value is smaller than 0 or larger than 255, the decompression aborts with return value -2
166	without reading any more data.
167
168	6) If `begin == end`, the decompression aborts with return value -2.
169
170	7) If the input iterator deferences into a value outside the 0 — 255 range, the decompression aborts with return value -2
171	without reading any more data.
172
173	8) If `length` bytes have been read from `begin` and the decompression is not yet complete, the decompression aborts with return value -2
174	without reading any more data.
175
176	9) A separate 32768-byte sliding window will be automatically and separately allocated for the decompression.
177
178	10) The output data buffer is assumed to persist during the call and doubles as the sliding window for the decompression.
179
180	11) The `first` field in the return value has the same meaning as the `int` type return value described earlier.
181	The `second` field in the return value contains the number of bytes that were consumed from the input.
182
183	12) The `first` field in the return value has the same meaning as the `int` type return value described earlier.
184	The `second` field in the return value contains the number of bytes that were written to the output.
185
186	13) The `first` field in the return value has the same meaning as the `int` type return value described earlier.
187	The `second.first` field in the return value contains the number of bytes that were consumed from the input.
188	The `second.second` field in the return value contains the number of bytes that were written to the output.
189
190	14) This method is non-backtrackable, and uses a bit more memory than the backtrackable ones.
191
192	15) This method is backtrackable, meaning that some bytes in the input may be read twice. It uses less memory than the non-backtrackable calls.
193
194	### Tips
195
196	Some of these definitions may be ambiguous.
197	If you hit a compiler error, choose a different call method.
198	To help distinguish between (`InputIterator`,`RandomAccessIterator`,`RandomAccessIterator`)
199	and (`ForwardIterator`,`ForwardIterator`,`OutputIterator`), make sure the input iterators
200	are _const_.
201
202	If you do multiple decompression calls in your program in different spots,
203	it may be wise to make sure they all use the same type of parameters,
204	to avoid having to instantiate multiple copies of `Deflate()`.
205	Lambda functors are an offender in this respect, because each lambda has a
206	unique type even if their contents and calling conventions are identical.
207	In the worst case, you can use `std::function` to wrap your calls
208	into a common interface. Check out this video for more about this topic: https://www.youtube.com/watch?v=rUB5Hlm9AaQ
209
210	## Requirements
211
212	```C++
213	// An InputFunctor has the following prototype,
214	// wherein type1 is convertible into unsigned char:
215	type1 input()
216
217	// An OutputFunctor has one of the following two prototypes,
218	// wherein type1 can accept unsigned int parameters in range 0-255:
219	void output(type1 byte_to_output)
220	bool output(type1 byte_to_output)
221
222	// A WindowFunctor has one of the following two prototypes,
223	// wherein type1 can accept unsigned int parameters in range 0-258,
224	// and type2 can accept unsigned int parameters:
225	void outputcopy(type1 length, type2 offs)
226	type2 outputcopy(type1 length, type2 offs)
227
228	// An InputIterator must have at least the following operations defined,
229	// where type1 is convertible into unsigned char:
230	const type1& operator*() const
231	InputIterator& operator++()
232
233	// A OutputIterator must have at least the following operations defined,
234	// where type1 is convertible into unsigned char:
235	type1& operator*() const
236	OutputIterator& operator++()
237
238	// A ForwardIterator must have at least the following operations defined,
239	// where type1 is convertible into unsigned char:
240	const type1& operator*() const
241	ForwardIterator& operator++()
242	bool operator==(const ForwardIterator&) const
243
244	// A RandomAccessIterator must have at least the following operations defined,
245	// where type1 is convertible into unsigned char,
246	// and type2 is a signed integer type (may be negative):
247	type1& operator*()
248	type1& operator[] (type2)
249	RandomAccessIterator operator- (type2)
250	RandomAccessIterator& operator++()
251	bool operator==(const RandomAccessIterator&) const
252	```
253
254	## Example use:
255
256	Decompress the standard input into the standard output (uses 32 kB automatically allocated window):
257
258	```C++
259	Deflate([]() { return std::getchar(); },
260	[](unsigned char byte) { std::putchar(byte); });
261
262	// Or more simply:
263
264	Deflate(std::getchar, std::putchar);
265	```
266
267	Decompress an array containing gzipped data into another array that must be large enough to hold the result.
268	A window buffer will not be allocated.
269
270	```C++
271	extern const char compressed_data[];
272	extern unsigned char outbuffer[131072];
273
274	Deflate(compressed_data+0, outbuffer+0);
275	```
276
277	Same as above, but with range checking for output, and reporting of written size:
278
279	```C++
280	extern const char compressed_data[];
281	extern unsigned char outbuffer[131072];
282
283	auto result = Deflate(compressed_data+0, outbuffer+0, sizeof(outbuffer), DeflateTrackOutSize{});
284	if(result.first != 0) std::fprintf(stderr, "Error %d\n", result.first);
285	std::fprintf(stderr, "%u bytes written\n", unsigned(result.second));
286	```
287
288	Same as above, but with range checking for both input and output:
289
290	```C++
291	extern const char compressed_data[];
292	extern unsigned compressed_data_length;
293	extern unsigned char outbuffer[131072];
294
295	int result = Deflate(compressed_data+0, compressed_data_length, outbuffer, outbuffer + sizeof(outbuffer));
296	if(result != 0) std::fprintf(stderr, "Error\n");
297	```
298
299	Decompress using a custom window function (the separate 32 kB window buffer will not be allocated):
300
301	```C++
302	std::vector<unsigned char> result;
303
304	Deflate(std::getchar,
305	[&](unsigned byte)
306	{
307	result.push_back(byte);
308	},
309	[&](unsigned length, unsigned offset)
310	{
311	if(!length)
312	{
313	// offset contains the maximum look-behind distance.
314	// You could use this information to allocate a buffer of a particular size.
315	// length=0 case is invoked exactly once before any length!=0 cases are.
316	}
317	while(length-- > 0)
318	{
319	result.push_back( result[result.size()-offset] );
320	}
321	});
322	```
323
324	Same as above, but stop decompressing once 4096 bytes have been written:
325
326	```C++
327	std::vector<unsigned char> result;
328
329	Deflate(std::getchar,
330	[&](unsigned byte)
331	{
332	if(result.size() >= 4096) return true;
333	result.push_back(byte);
334	return false;
335	},
336	[&](unsigned length, unsigned offset)
337	{
338	if(!length)
339	{
340	// offset contains the maximum look-behind distance.
341	// You could use this information to allocate a buffer of a particular size.
342	// length=0 case is invoked exactly once before any length!=0 cases are.
343	}
344	for(; result.size() < 4096 && length > 0; --length)
345	{
346	result.push_back( result[result.size()-offset] );
347	}
348	return length;
349	});
350	```
351
352	## Misnomer
353
354	Yes, I am aware that the project is technically named misleadingly.
355	This project implements the _inflate_ algorithm (decompression),
356	not _deflate_ (compression).
357
358	In my defense, the _compression format_ is called deflate. There is no _inflate_ format.
359	This library decompresses data that has been compressed with _deflate_.
360
361	Think name, not verb.
362