Feature/dragonbox floats #8883
Feature/dragonbox floats #8883
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aardappel
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aardappel
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Can you put some float formatting tests somewhere? With a wide variety of floats.. then run them both with the old and the new code.
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| // Copyright 2020-2025 Junekey Jeon | |||
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This header contains a TON of general float functionality that is not needed for just the task of float 2 string.. I wonder if there is a more minimal version?
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I believe we can strip this down all we want -- I just brought in the files wholesale.
include/flatbuffers/util.h
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| ss << t; | ||
| auto s = ss.str(); | ||
| // Handle NaN | ||
| if (std::isnan(t)) { |
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Ok, so how does dragonbox output these? Does it handle them at all? I know its supposed to be fast, but is all this checking potentially slow things down?
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The is_decimal function states these are preconditions - if you pass them in you get an assertion failure.
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I'll note that the checks probably aren't anywhere near the slowest part of this (or any other part of the code that uses this) -- this code is riddled with std::string allocations :)
include/flatbuffers/util.h
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| } | ||
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| // Handle zero (preserve sign of -0.0 if desired) | ||
| if (t == T{0}) { |
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Why does this need a special case?
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from the repo readme:
// Here, x should be a nonzero finite number!
// The return value v is a struct with three members:
// significand : decimal significand (1234 in this case);
// it is of type std::uint64_t for double, std::uint32_t for float
// exponent : decimal exponent (-3 in this case); it is of type int
// is_negative : as the name suggests; it is of type bool
auto v = jkj::dragonbox::to_decimal(x);
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refactored to hide the dragonbox impl and add access to old functions. still need to add tests. |
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@aardappel added some tests -- if you comment in the line I added to CMakelists.txt you can run the old method. |
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alright, I got everything but windows happy - it is mad about some type casting that I will have to run down later. |
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Fixes #8573