Externals: Add libfmt 5.3.0 to externals

Allows us to migrate off of printf specifiers and have more type-safe
formatting facilities. It also allows for custom type support as well.
fmt is also on track to have part of it standardized within C++2a, so
this will also lessen the transitional work necessary later on by
allowing new code to use it.

This simply adds the library but doesn't do anything with it yet.
This commit is contained in:
Lioncash
2019-06-10 14:54:12 -04:00
parent cea1b58919
commit d5d60c6e64
42 changed files with 13685 additions and 0 deletions

53
Externals/fmt/support/compute-powers.py vendored Executable file
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#!/usr/bin/env python
# Compute 10 ** exp with exp in the range [min_exponent, max_exponent] and print
# normalized (with most-significant bit equal to 1) significands in hexadecimal.
from __future__ import print_function
min_exponent = -348
max_exponent = 340
step = 8
significand_size = 64
exp_offset = 2000
class fp:
pass
powers = []
for i, exp in enumerate(range(min_exponent, max_exponent + 1, step)):
result = fp()
n = 10 ** exp if exp >= 0 else 2 ** exp_offset / 10 ** -exp
k = significand_size + 1
# Convert to binary and round.
binary = '{:b}'.format(n)
result.f = (int('{:0<{}}'.format(binary[:k], k), 2) + 1) / 2
result.e = len(binary) - (exp_offset if exp < 0 else 0) - significand_size
powers.append(result)
# Sanity check.
exp_offset10 = 400
actual = result.f * 10 ** exp_offset10
if result.e > 0:
actual *= 2 ** result.e
else:
for j in range(-result.e):
actual /= 2
expected = 10 ** (exp_offset10 + exp)
precision = len('{}'.format(expected)) - len('{}'.format(actual - expected))
if precision < 19:
print('low precision:', precision)
exit(1)
print('Significands:', end='')
for i, fp in enumerate(powers):
if i % 3 == 0:
print(end='\n ')
print(' {:0<#16x}'.format(fp.f, ), end=',')
print('\n\nExponents:', end='')
for i, fp in enumerate(powers):
if i % 11 == 0:
print(end='\n ')
print(' {:5}'.format(fp.e), end=',')
print('\n\nMax exponent difference:',
max([x.e - powers[i - 1].e for i, x in enumerate(powers)][1:]))