Commit f92b4b52 authored by Brad King's avatar Brad King

Merge branch 'upstream-zstd' into import-zstd

* upstream-zstd:
  zstd 2018-12-27 (470344d3)
parents 9337cbfc fbaf6563
BSD License
For Zstandard software
Copyright (c) 2016-present, Facebook, Inc. All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name Facebook nor the names of its contributors may be used to
endorse or promote products derived from this software without specific
prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
<p align="center"><img src="https://raw.githubusercontent.com/facebook/zstd/dev/doc/images/zstd_logo86.png" alt="Zstandard"></p>
__Zstandard__, or `zstd` as short version, is a fast lossless compression algorithm,
targeting real-time compression scenarios at zlib-level and better compression ratios.
It's backed by a very fast entropy stage, provided by [Huff0 and FSE library](https://github.com/Cyan4973/FiniteStateEntropy).
The project is provided as an open-source dual [BSD](LICENSE) and [GPLv2](COPYING) licensed **C** library,
and a command line utility producing and decoding `.zst`, `.gz`, `.xz` and `.lz4` files.
Should your project require another programming language,
a list of known ports and bindings is provided on [Zstandard homepage](http://www.zstd.net/#other-languages).
**Development branch status:**
[![Build Status][travisDevBadge]][travisLink]
[![Build status][AppveyorDevBadge]][AppveyorLink]
[![Build status][CircleDevBadge]][CircleLink]
[travisDevBadge]: https://travis-ci.org/facebook/zstd.svg?branch=dev "Continuous Integration test suite"
[travisLink]: https://travis-ci.org/facebook/zstd
[AppveyorDevBadge]: https://ci.appveyor.com/api/projects/status/xt38wbdxjk5mrbem/branch/dev?svg=true "Windows test suite"
[AppveyorLink]: https://ci.appveyor.com/project/YannCollet/zstd-p0yf0
[CircleDevBadge]: https://circleci.com/gh/facebook/zstd/tree/dev.svg?style=shield "Short test suite"
[CircleLink]: https://circleci.com/gh/facebook/zstd
## Benchmarks
For reference, several fast compression algorithms were tested and compared
on a server running Linux Debian (`Linux version 4.14.0-3-amd64`),
with a Core i7-6700K CPU @ 4.0GHz,
using [lzbench], an open-source in-memory benchmark by @inikep
compiled with [gcc] 7.3.0,
on the [Silesia compression corpus].
[lzbench]: https://github.com/inikep/lzbench
[Silesia compression corpus]: http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia
[gcc]: https://gcc.gnu.org/
| Compressor name | Ratio | Compression| Decompress.|
| --------------- | ------| -----------| ---------- |
| **zstd 1.3.4 -1** | 2.877 | 470 MB/s | 1380 MB/s |
| zlib 1.2.11 -1 | 2.743 | 110 MB/s | 400 MB/s |
| brotli 1.0.2 -0 | 2.701 | 410 MB/s | 430 MB/s |
| quicklz 1.5.0 -1 | 2.238 | 550 MB/s | 710 MB/s |
| lzo1x 2.09 -1 | 2.108 | 650 MB/s | 830 MB/s |
| lz4 1.8.1 | 2.101 | 750 MB/s | 3700 MB/s |
| snappy 1.1.4 | 2.091 | 530 MB/s | 1800 MB/s |
| lzf 3.6 -1 | 2.077 | 400 MB/s | 860 MB/s |
[zlib]: http://www.zlib.net/
[LZ4]: http://www.lz4.org/
Zstd can also offer stronger compression ratios at the cost of compression speed.
Speed vs Compression trade-off is configurable by small increments.
Decompression speed is preserved and remains roughly the same at all settings,
a property shared by most LZ compression algorithms, such as [zlib] or lzma.
The following tests were run
on a server running Linux Debian (`Linux version 4.14.0-3-amd64`)
with a Core i7-6700K CPU @ 4.0GHz,
using [lzbench], an open-source in-memory benchmark by @inikep
compiled with [gcc] 7.3.0,
on the [Silesia compression corpus].
Compression Speed vs Ratio | Decompression Speed
---------------------------|--------------------
![Compression Speed vs Ratio](doc/images/CSpeed2.png "Compression Speed vs Ratio") | ![Decompression Speed](doc/images/DSpeed3.png "Decompression Speed")
A few other algorithms can produce higher compression ratios at slower speeds, falling outside of the graph.
For a larger picture including slow modes, [click on this link](doc/images/DCspeed5.png).
## The case for Small Data compression
Previous charts provide results applicable to typical file and stream scenarios (several MB). Small data comes with different perspectives.
The smaller the amount of data to compress, the more difficult it is to compress. This problem is common to all compression algorithms, and reason is, compression algorithms learn from past data how to compress future data. But at the beginning of a new data set, there is no "past" to build upon.
To solve this situation, Zstd offers a __training mode__, which can be used to tune the algorithm for a selected type of data.
Training Zstandard is achieved by providing it with a few samples (one file per sample). The result of this training is stored in a file called "dictionary", which must be loaded before compression and decompression.
Using this dictionary, the compression ratio achievable on small data improves dramatically.
The following example uses the `github-users` [sample set](https://github.com/facebook/zstd/releases/tag/v1.1.3), created from [github public API](https://developer.github.com/v3/users/#get-all-users).
It consists of roughly 10K records weighing about 1KB each.
Compression Ratio | Compression Speed | Decompression Speed
------------------|-------------------|--------------------
![Compression Ratio](doc/images/dict-cr.png "Compression Ratio") | ![Compression Speed](doc/images/dict-cs.png "Compression Speed") | ![Decompression Speed](doc/images/dict-ds.png "Decompression Speed")
These compression gains are achieved while simultaneously providing _faster_ compression and decompression speeds.
Training works if there is some correlation in a family of small data samples. The more data-specific a dictionary is, the more efficient it is (there is no _universal dictionary_).
Hence, deploying one dictionary per type of data will provide the greatest benefits.
Dictionary gains are mostly effective in the first few KB. Then, the compression algorithm will gradually use previously decoded content to better compress the rest of the file.
### Dictionary compression How To:
1. Create the dictionary
`zstd --train FullPathToTrainingSet/* -o dictionaryName`
2. Compress with dictionary
`zstd -D dictionaryName FILE`
3. Decompress with dictionary
`zstd -D dictionaryName --decompress FILE.zst`
## Build instructions
### Makefile
If your system is compatible with standard `make` (or `gmake`),
invoking `make` in root directory will generate `zstd` cli in root directory.
Other available options include:
- `make install` : create and install zstd cli, library and man pages
- `make check` : create and run `zstd`, tests its behavior on local platform
### cmake
A `cmake` project generator is provided within `build/cmake`.
It can generate Makefiles or other build scripts
to create `zstd` binary, and `libzstd` dynamic and static libraries.
By default, `CMAKE_BUILD_TYPE` is set to `Release`.
### Meson
A Meson project is provided within [`build/meson`](build/meson). Follow
build instructions in that directory.
You can also take a look at [`.travis.yml`](.travis.yml) file for an
example about how Meson is used to build this project.
Note that default build type is **release**.
### Visual Studio (Windows)
Going into `build` directory, you will find additional possibilities:
- Projects for Visual Studio 2005, 2008 and 2010.
+ VS2010 project is compatible with VS2012, VS2013, VS2015 and VS2017.
- Automated build scripts for Visual compiler by [@KrzysFR](https://github.com/KrzysFR), in `build/VS_scripts`,
which will build `zstd` cli and `libzstd` library without any need to open Visual Studio solution.
### Buck
You can build the zstd binary via buck by executing: `buck build programs:zstd` from the root of the repo.
The output binary will be in `buck-out/gen/programs/`.
## Status
Zstandard is currently deployed within Facebook. It is used continuously to compress large amounts of data in multiple formats and use cases.
Zstandard is considered safe for production environments.
## License
Zstandard is dual-licensed under [BSD](LICENSE) and [GPLv2](COPYING).
## Contributing
The "dev" branch is the one where all contributions are merged before reaching "master".
If you plan to propose a patch, please commit into the "dev" branch, or its own feature branch.
Direct commit to "master" are not permitted.
For more information, please read [CONTRIBUTING](CONTRIBUTING.md).
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/*
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
#ifndef ZSTD_COMPILER_H
#define ZSTD_COMPILER_H
/*-*******************************************************
* Compiler specifics
*********************************************************/
/* force inlining */
#if !defined(ZSTD_NO_INLINE)
#if defined (__GNUC__) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */
# define INLINE_KEYWORD inline
#else
# define INLINE_KEYWORD
#endif
#if defined(__GNUC__)
# define FORCE_INLINE_ATTR __attribute__((always_inline))
#elif defined(_MSC_VER)
# define FORCE_INLINE_ATTR __forceinline
#else
# define FORCE_INLINE_ATTR
#endif
#else
#define INLINE_KEYWORD
#define FORCE_INLINE_ATTR
#endif
/**
* FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant
* parameters. They must be inlined for the compiler to elimininate the constant
* branches.
*/
#define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR
/**
* HINT_INLINE is used to help the compiler generate better code. It is *not*
* used for "templates", so it can be tweaked based on the compilers
* performance.
*
* gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the
* always_inline attribute.
*
* clang up to 5.0.0 (trunk) benefit tremendously from the always_inline
* attribute.
*/
#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5
# define HINT_INLINE static INLINE_KEYWORD
#else
# define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR
#endif
/* force no inlining */
#ifdef _MSC_VER
# define FORCE_NOINLINE static __declspec(noinline)
#else
# ifdef __GNUC__
# define FORCE_NOINLINE static __attribute__((__noinline__))
# else
# define FORCE_NOINLINE static
# endif
#endif
/* target attribute */
#ifndef __has_attribute
#define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */
#endif
#if defined(__GNUC__)
# define TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
#else
# define TARGET_ATTRIBUTE(target)
#endif
/* Enable runtime BMI2 dispatch based on the CPU.
* Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.
*/
#ifndef DYNAMIC_BMI2
#if ((defined(__clang__) && __has_attribute(__target__)) \
|| (defined(__GNUC__) \
&& (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \
&& (defined(__x86_64__) || defined(_M_X86)) \
&& !defined(__BMI2__)
# define DYNAMIC_BMI2 1
#else
# define DYNAMIC_BMI2 0
#endif
#endif
/* prefetch
* can be disabled, by declaring NO_PREFETCH build macro */
#if defined(NO_PREFETCH)
# define PREFETCH_L1(ptr) (void)(ptr) /* disabled */
# define PREFETCH_L2(ptr) (void)(ptr) /* disabled */
#else
# if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) /* _mm_prefetch() is not defined outside of x86/x64 */
# include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */
# define PREFETCH_L1(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T0)
# define PREFETCH_L2(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T1)
# elif defined(__GNUC__) && ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) )
# define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */)
# define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */)
# else
# define PREFETCH_L1(ptr) (void)(ptr) /* disabled */
# define PREFETCH_L2(ptr) (void)(ptr) /* disabled */
# endif
#endif /* NO_PREFETCH */
#define CACHELINE_SIZE 64
#define PREFETCH_AREA(p, s) { \
const char* const _ptr = (const char*)(p); \
size_t const _size = (size_t)(s); \
size_t _pos; \
for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \
PREFETCH_L2(_ptr + _pos); \
} \
}
/* disable warnings */
#ifdef _MSC_VER /* Visual Studio */
# include <intrin.h> /* For Visual 2005 */
# pragma warning(disable : 4100) /* disable: C4100: unreferenced formal parameter */
# pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
# pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */
# pragma warning(disable : 4214) /* disable: C4214: non-int bitfields */
# pragma warning(disable : 4324) /* disable: C4324: padded structure */
#endif
#endif /* ZSTD_COMPILER_H */
/*
* Copyright (c) 2018-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
#ifndef ZSTD_COMMON_CPU_H
#define ZSTD_COMMON_CPU_H
/**
* Implementation taken from folly/CpuId.h
* https://github.com/facebook/folly/blob/master/folly/CpuId.h
*/
#include <string.h>
#include "mem.h"
#ifdef _MSC_VER
#include <intrin.h>
#endif
typedef struct {
U32 f1c;
U32 f1d;
U32 f7b;
U32 f7c;
} ZSTD_cpuid_t;
MEM_STATIC ZSTD_cpuid_t ZSTD_cpuid(void) {
U32 f1c = 0;
U32 f1d = 0;
U32 f7b = 0;
U32 f7c = 0;
#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_IX86))
int reg[4];
__cpuid((int*)reg, 0);
{
int const n = reg[0];
if (n >= 1) {
__cpuid((int*)reg, 1);
f1c = (U32)reg[2];
f1d = (U32)reg[3];
}
if (n >= 7) {
__cpuidex((int*)reg, 7, 0);
f7b = (U32)reg[1];
f7c = (U32)reg[2];
}
}
#elif defined(__i386__) && defined(__PIC__) && !defined(__clang__) && defined(__GNUC__)
/* The following block like the normal cpuid branch below, but gcc
* reserves ebx for use of its pic register so we must specially
* handle the save and restore to avoid clobbering the register
*/
U32 n;
__asm__(
"pushl %%ebx\n\t"
"cpuid\n\t"
"popl %%ebx\n\t"
: "=a"(n)
: "a"(0)
: "ecx", "edx");
if (n >= 1) {
U32 f1a;
__asm__(
"pushl %%ebx\n\t"
"cpuid\n\t"
"popl %%ebx\n\t"
: "=a"(f1a), "=c"(f1c), "=d"(f1d)
: "a"(1));
}
if (n >= 7) {
__asm__(
"pushl %%ebx\n\t"
"cpuid\n\t"
"movl %%ebx, %%eax\n\t"
"popl %%ebx"
: "=a"(f7b), "=c"(f7c)
: "a"(7), "c"(0)
: "edx");
}
#elif defined(__x86_64__) || defined(_M_X64) || defined(__i386__)
U32 n;
__asm__("cpuid" : "=a"(n) : "a"(0) : "ebx", "ecx", "edx");
if (n >= 1) {
U32 f1a;
__asm__("cpuid" : "=a"(f1a), "=c"(f1c), "=d"(f1d) : "a"(1) : "ebx");
}
if (n >= 7) {
U32 f7a;
__asm__("cpuid"
: "=a"(f7a), "=b"(f7b), "=c"(f7c)
: "a"(7), "c"(0)
: "edx");
}
#endif
{
ZSTD_cpuid_t cpuid;
cpuid.f1c = f1c;
cpuid.f1d = f1d;
cpuid.f7b = f7b;
cpuid.f7c = f7c;
return cpuid;
}
}
#define X(name, r, bit) \
MEM_STATIC int ZSTD_cpuid_##name(ZSTD_cpuid_t const cpuid) { \
return ((cpuid.r) & (1U << bit)) != 0; \
}
/* cpuid(1): Processor Info and Feature Bits. */
#define C(name, bit) X(name, f1c, bit)
C(sse3, 0)
C(pclmuldq, 1)
C(dtes64, 2)
C(monitor, 3)
C(dscpl, 4)
C(vmx, 5)
C(smx, 6)
C(eist, 7)
C(tm2, 8)
C(ssse3, 9)
C(cnxtid, 10)
C(fma, 12)
C(cx16, 13)
C(xtpr, 14)
C(pdcm, 15)
C(pcid, 17)
C(dca, 18)
C(sse41, 19)
C(sse42, 20)
C(x2apic, 21)
C(movbe, 22)
C(popcnt, 23)
C(tscdeadline, 24)
C(aes, 25)
C(xsave, 26)
C(osxsave, 27)
C(avx, 28)
C(f16c, 29)
C(rdrand, 30)
#undef C
#define D(name, bit) X(name, f1d, bit)
D(fpu, 0)
D(vme, 1)
D(de, 2)
D(pse, 3)
D(tsc, 4)
D(msr, 5)
D(pae, 6)
D(mce, 7)
D(cx8, 8)
D(apic, 9)
D(sep, 11)
D(mtrr, 12)
D(pge, 13)
D(mca, 14)
D(cmov, 15)
D(pat, 16)
D(pse36, 17)
D(psn, 18)
D(clfsh, 19)
D(ds, 21)
D(acpi, 22)
D(mmx, 23)
D(fxsr, 24)
D(sse, 25)
D(sse2, 26)
D(ss, 27)
D(htt, 28)
D(tm, 29)
D(pbe, 31)
#undef D
/* cpuid(7): Extended Features. */
#define B(name, bit) X(name, f7b, bit)
B(bmi1, 3)
B(hle, 4)
B(avx2, 5)
B(smep, 7)
B(bmi2, 8)
B(erms, 9)
B(invpcid, 10)
B(rtm, 11)
B(mpx, 14)
B(avx512f, 16)
B(avx512dq, 17)
B(rdseed, 18)
B(adx, 19)
B(smap, 20)
B(avx512ifma, 21)
B(pcommit, 22)
B(clflushopt, 23)
B(clwb, 24)
B(avx512pf, 26)
B(avx512er, 27)
B(avx512cd, 28)
B(sha, 29)
B(avx512bw, 30)
B(avx512vl, 31)
#undef B
#define C(name, bit) X(name, f7c, bit)
C(prefetchwt1, 0)
C(avx512vbmi, 1)
#undef C
#undef X
#endif /* ZSTD_COMMON_CPU_H */
/* ******************************************************************
debug
Part of FSE library
Copyright (C) 2013-present, Yann Collet.
BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
You can contact the author at :
- Source repository : https://github.com/Cyan4973/FiniteStateEntropy
****************************************************************** */
/*
* This module only hosts one global variable
* which can be used to dynamically influence the verbosity of traces,
* such as DEBUGLOG and RAWLOG
*/
#include "debug.h"
int g_debuglevel = DEBUGLEVEL;
/* ******************************************************************
debug
Part of FSE library
Copyright (C) 2013-present, Yann Collet.
BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
You can contact the author at :
- Source repository : https://github.com/Cyan4973/FiniteStateEntropy
****************************************************************** */
/*
* The purpose of this header is to enable debug functions.
* They regroup assert(), DEBUGLOG() and RAWLOG() for run-time,
* and DEBUG_STATIC_ASSERT() for compile-time.
*
* By default, DEBUGLEVEL==0, which means run-time debug is disabled.
*
* Level 1 enables assert() only.
* Starting level 2, traces can be generated and pushed to stderr.
* The higher the level, the more verbose the traces.
*
* It's possible to dynamically adjust level using variable g_debug_level,
* which is only declared if DEBUGLEVEL>=2,
* and is a global variable, not multi-thread protected (use with care)
*/
#ifndef DEBUG_H_12987983217
#define DEBUG_H_12987983217
#if defined (__cplusplus)
extern "C" {
#endif
/* static assert is triggered at compile time, leaving no runtime artefact.
* static assert only works with compile-time constants.
* Also, this variant can only be used inside a function. */
#define DEBUG_STATIC_ASSERT(c) (void)sizeof(char[(c) ? 1 : -1])
/* DEBUGLEVEL is expected to be defined externally,
* typically through compiler command line.
* Value must be a number. */
#ifndef DEBUGLEVEL
# define DEBUGLEVEL 0
#endif
/* DEBUGFILE can be defined externally,
* typically through compiler command line.
* note : currently useless.
* Value must be stderr or stdout */
#ifndef DEBUGFILE
# define DEBUGFILE stderr
#endif
/* recommended values for DEBUGLEVEL :
* 0 : release mode, no debug, all run-time checks disabled
* 1 : enables assert() only, no display
* 2 : reserved, for currently active debug path
* 3 : events once per object lifetime (CCtx, CDict, etc.)
* 4 : events once per frame
* 5 : events once per block
* 6 : events once per sequence (verbose)
* 7+: events at every position (*very* verbose)
*
* It's generally inconvenient to output traces > 5.
* In which case, it's possible to selectively trigger high verbosity levels
* by modifying g_debug_level.
*/
#if (DEBUGLEVEL>=1)
# include <assert.h>
#else
# ifndef assert /* assert may be already defined, due to prior #include <assert.h> */
# define assert(condition) ((void)0) /* disable assert (default) */
# endif
#endif
#if (DEBUGLEVEL>=2)
# include <stdio.h>
extern int g_debuglevel; /* the variable is only declared,
it actually lives in debug.c,
and is shared by the whole process.
It's not thread-safe.
It's useful when enabling very verbose levels
on selective conditions (such as position in src) */
# define RAWLOG(l, ...) { \
if (l<=g_debuglevel) { \
fprintf(stderr, __VA_ARGS__); \