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65 lines
1.9 KiB
Nim
65 lines
1.9 KiB
Nim
#
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#
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# Nim's Runtime Library
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# (c) Copyright 2019 Nim contributors
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#
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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#
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when not defined(nimLegacyAddFloat) and not defined(nimscript) and
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not defined(js) and defined(nimHasDragonBox):
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import dragonbox
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proc writeFloatToBuffer*(buf: var array[65, char]; value: BiggestFloat): int =
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## This is the implementation to format floats.
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##
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## returns the amount of bytes written to `buf` not counting the
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## terminating '\0' character.
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result = toChars(buf, value, forceTrailingDotZero=true)
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buf[result] = '\0'
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else:
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proc c_sprintf(buf, frmt: cstring): cint {.header: "<stdio.h>",
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importc: "sprintf", varargs, noSideEffect.}
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proc writeToBuffer(buf: var array[65, char]; value: cstring) =
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var i = 0
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while value[i] != '\0':
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buf[i] = value[i]
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inc i
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proc writeFloatToBuffer*(buf: var array[65, char]; value: BiggestFloat): int =
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## This is the implementation to format floats.
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##
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## returns the amount of bytes written to `buf` not counting the
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## terminating '\0' character.
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var n: int = c_sprintf(addr buf, "%.16g", value)
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var hasDot = false
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for i in 0..n-1:
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if buf[i] == ',':
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buf[i] = '.'
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hasDot = true
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elif buf[i] in {'a'..'z', 'A'..'Z', '.'}:
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hasDot = true
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if not hasDot:
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buf[n] = '.'
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buf[n+1] = '0'
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buf[n+2] = '\0'
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result = n + 2
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else:
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result = n
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# On Windows nice numbers like '1.#INF', '-1.#INF' or '1.#NAN' or 'nan(ind)'
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# of '-1.#IND' are produced.
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# We want to get rid of these here:
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if buf[n-1] in {'n', 'N', 'D', 'd', ')'}:
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writeToBuffer(buf, "nan")
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result = 3
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elif buf[n-1] == 'F':
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if buf[0] == '-':
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writeToBuffer(buf, "-inf")
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result = 4
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else:
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writeToBuffer(buf, "inf")
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result = 3
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