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base repository: crystal-lang/crystal
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  • 5 commits
  • 11 files changed
  • 1 contributor

Commits on Jun 4, 2017

  1. Add FloatPrinter based on Grisu3 

    This improves the speed of transforming floats to their string
representation. It is based on the 2004 paper "Printing Floating-Point
Numbers Quickly and Accurately with Integers" by Florian Loitsch[1].

Most of the code is a port from the BSD-licensed C++ project
"double-conversion"[2], which was extracted from the V8 engine.

The Grisu3 algorithm is fast because it deals only with fixed-sized
integer arithmetic. It takes advantage extra bits leftover from the
53-bit significand in a 64 bit number to help find the optimal string
representation. However this only works for 95.5% of floats and it
rejects the remaining 0.5%. Rejected numbers still need to be printed
with some other, slower method.

1: http://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf
2: https://github.com/google/double-conversion
    @will @asterite
    will authored and asterite committed Jun 4, 2017
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  2. FloatPrinter: make docs and interface more consistent

    @will @asterite
    will authored and asterite committed Jun 4, 2017
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  3. FloatPrinter: fix -NaN test, fix formatting

    @will @asterite
    will authored and asterite committed Jun 4, 2017
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  4. FloatPrinter: add Float32 support

    @will @asterite
    will authored and asterite committed Jun 4, 2017
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  5. FloatPrinter: add license to specs

    @will @asterite
    will authored and asterite committed Jun 4, 2017
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