third_party/gmp/mini-gmp/README

Copyright 2011-2013, 2018 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

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or

  * the GNU General Public License as published by the Free Software
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    later version.

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This is "mini-gmp", a small implementation of a subset of GMP's mpn,
mpz and mpq interfaces.

It is intended for applications which need arithmetic on numbers
larger than a machine word, but which don't need to handle very large
numbers very efficiently. Those applications can include a copy of
mini-gmp to get a GMP-compatible interface with small footprint. One
can also arrange for optional linking with the real GMP library, using
mini-gmp as a fallback when for some reason GMP is not available, or
not desired as a dependency.

The supported GMP subset of the mpn and mpz interfaces is declared in
mini-gmp.h, and implemented in mini-gmp.c. The implemented
functions are fully compatible with the corresponding GMP functions,
as specified in the GMP manual, with a few exceptions:

  mpz_export and mpz_import support only NAILS = 0.

  The REALLOC_FUNC and FREE_FUNC registered with
  mp_set_memory_functions does not get the correct size of the
  allocated block in the corresponding argument. mini-gmp always
  passes zero for these rarely used arguments.

  When mpz_get_str allocates the block, it can be longer than needed.

The performance target for mini-gmp is to be at most 10 times slower
than the real GMP library, for numbers of size up to a few hundred
bits. No asymptotically fast algorithms are included in mini-gmp, so
it will be many orders of magnitude slower than GMP for very large
numbers.

The supported GMP subset of the mpq layer is declared in mini-mpq.h,
and implemented in mini-mpq.c.

You should never "install" mini-gmp. Applications can either just
#include mini-gmp.c (but then, beware that it defines several macros
and functions outside of the advertised interface), and if needed
#include mini-mpq.c in a later line (order is important). Or compile
mini-gmp.c and mini-mpq.c as separate compilation units, and use the
declarations in mini-gmp.h and mini-mpq.h.

The tests subdirectory contains a testsuite. To use it, you need GMP
and GNU make. Just run make check in the tests directory. If the
hard-coded compiler settings are not right, you have to either edit the
Makefile or pass overriding values on the make command line (e.g.,
make CC=cc check).

The initial version of mini-gmp was put together by Niels Möller
<nisse@lysator.liu.se>, with a fair amount of copy-and-paste from the
GMP sources.