kyawakyawa / nanostl

NanoSTL, a small subset of C++ STL and libm

NanoSTL, a portable and small subset of C++ STL.

NanoSTL is good for using STL-like feature in your C++ application and C++-like JIT compiler.

NanoSTL is portable, it should run well on many environments including Windows, Linux, macOS, x86, ARM, SPARC, etc.

NanoSTL should work well on C++11 compiler or later. (C++03 or earlier is not supported)

Status

Eearly testing stage. Not ready for the production use.

Features

• Experimental CUDA support. You can use NanoSTL on device functions.
  • See sandbox/cuda/

Supported features

• vector
• string
  • to_string(float)(using ryu)
  • to_string(double)(using ryu)
  • stof(string to float. using ryu_parse)
  • stod(string to double. using ryu_parse)
• algorithm
• limits
• map

Be careful! Not all C++ STL functions are supported for each module.

Limited support

• math : Approximate math functions. Please keep in mind this is basically not be IEEE-754 compliant and does not consier a processor's rounding mode.
• valarray
• cstring
  • memcpy
  • memmove
  • strcpy
  • strncpy
  • strcat
  • strncat
  • memcmp
  • strcmp
  • strcoll
  • strncmp
  • strxfrm
  • memchr
  • strchr
  • strcspn
  • strpbrk
  • strrchr
  • strspn
  • strstr
  • strtok
  • memset
  • strerror
  • strlen
  • NULL
  • size_t

math functions

• isnan
• isinf
• isfinite
• isnormal
• fabs(float)
• copysign(float)
• sqrt(float) Approximated.
• exp(float)
• pow(float)
• log(float)
• log10(float)
• sin(float)
• cos(float)
• tanh(float)
• cbrt(float)
• erf(float)
• erfc(float)
• ierf(float)

Other list of implementation status

• cassert
  • assert
    • CUDA
    • Other platform
• To be filled...

Supported architectures

• 64bit and 32bit machine.
• Big endian and little endian
  • Some math functions may not run on big endian machine.
• CUDA device.

Supported compilers

Even though NanoSTL should be compilable with older and various C++ compilers, at least following compilers shold work well.

• gcc 4.4.7+
  • NanoSTL itself can be compilable with gcc 4.2.4(fails to compile Catch unit test code)
• clang 3.4+

Types

NanoSTL assumes following type definitions.

• char : 8bit(NOTE: unsigned is default for some ARM compiler. Use signed char if you want signed 8bit type)
• short : 16bit
• int : 32bit
• long long : 64bit
• float : 32bit IEEE754 floating point.
• double : 64bit IEEE754 floating point.

Compiler macros

• NANOSTL_BIG_ENDIAN Set endianness to big endian. Considering to support various compilers, user must explicitly specify endianness to the compiler. Default is little endian.

Differences compared to (full featured) C++ STL

• No thread safety Currently NanoSTL is not thread safe
  • Application must care about the thread safety
  • For example, need to use mutex or lock for nanostl::vector::push_back() operation if you are accesing nanostl::vector object from multiple threads.
• RTTI and exception is not supported.
• Returns NULL when memory allocation failed(no bad_alloc)
• stof, stod
  • Return (signaling) NaN for invalid input

TODO

• iostream, fstream(stdout/stdin, file IO)
• Math complex type
• CUDA support(experimental)
• isnan/isinf/isfinite support
• Unit tests
  • Unit tests on CUDA platform
  • Write mote unit tests for CPU platform
• Multithread support
• Backport of some C++11 features(e.g. unordered_map)
• Replace oiio math functions so that we can have clean MIT licensed code.
• FLOAT16 and BFLOAT16 support.

Developer note

Generate single header file.

$ python scripts/generateSingleHeader.py

Unit tests

Compiling unit test requires C++11 compiler since unit test uses some C++11 math functions for the reference.

$ cd tests
$ make
$ ./test

Debugging

Use NANOSTL_DEBUG define for debugging.

Licenss

Unless otherwise expressed, NanoSTL is licensed under MIT license. Some functions in nanomath is licenced under modified BSD license.

Third party licenses

• acutest : MIT license.
• faster math functions: Some math functions implemented in nanomath is grabbed from OpenImageIO fmath.h, which is licensed under modified BSD license. https://github.com/OpenImageIO/oiio/
• ryu(floating point <-> string converter). NanoSTL choose Boost 1.0 license. https://github.com/ulfjack/ryu