move formatfloat out of system (#20195)

* move formatfloat out of system

* fixes doc

* Update changelog.md

* careless

* fixes

* deprecate system/formatfloat

* better handling

1 files changed, 6 insertions, 135 deletions

diff --git a/lib/system/formatfloat.nim b/lib/system/formatfloat.nim
index aada3e1bf..70dd857d5 100644
--- a/lib/system/formatfloat.nim
+++ b/lib/system/formatfloat.nim
@@ -1,135 +1,6 @@
-#
-#
-#            Nim's Runtime Library
-#        (c) Copyright 2019 Nim contributors
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-when defined(nimPreviewSlimSystem):
-  import std/assertions
-
-proc c_memcpy(a, b: pointer, size: csize_t): pointer {.importc: "memcpy", header: "<string.h>", discardable.}
-
-proc addCstringN(result: var string, buf: cstring; buflen: int) =
-  # no nimvm support needed, so it doesn't need to be fast here either
-  let oldLen = result.len
-  let newLen = oldLen + buflen
-  result.setLen newLen
-  c_memcpy(result[oldLen].addr, buf, buflen.csize_t)
-
-import dragonbox, schubfach
-
-proc writeFloatToBufferRoundtrip*(buf: var array[65, char]; value: BiggestFloat): int =
-  ## This is the implementation to format floats.
-  ##
-  ## returns the amount of bytes written to `buf` not counting the
-  ## terminating '\0' character.
-  result = toChars(buf, value, forceTrailingDotZero=true)
-  buf[result] = '\0'
-
-proc writeFloatToBufferRoundtrip*(buf: var array[65, char]; value: float32): int =
-  result = float32ToChars(buf, value, forceTrailingDotZero=true)
-  buf[result] = '\0'
-
-proc c_sprintf(buf, frmt: cstring): cint {.header: "<stdio.h>",
-                                    importc: "sprintf", varargs, noSideEffect.}
-
-proc writeToBuffer(buf: var array[65, char]; value: cstring) =
-  var i = 0
-  while value[i] != '\0':
-    buf[i] = value[i]
-    inc i
-
-proc writeFloatToBufferSprintf*(buf: var array[65, char]; value: BiggestFloat): int =
-  ## This is the implementation to format floats.
-  ##
-  ## returns the amount of bytes written to `buf` not counting the
-  ## terminating '\0' character.
-  var n: int = c_sprintf(addr buf, "%.16g", value)
-  var hasDot = false
-  for i in 0..n-1:
-    if buf[i] == ',':
-      buf[i] = '.'
-      hasDot = true
-    elif buf[i] in {'a'..'z', 'A'..'Z', '.'}:
-      hasDot = true
-  if not hasDot:
-    buf[n] = '.'
-    buf[n+1] = '0'
-    buf[n+2] = '\0'
-    result = n + 2
-  else:
-    result = n
-  # On Windows nice numbers like '1.#INF', '-1.#INF' or '1.#NAN' or 'nan(ind)'
-  # of '-1.#IND' are produced.
-  # We want to get rid of these here:
-  if buf[n-1] in {'n', 'N', 'D', 'd', ')'}:
-    writeToBuffer(buf, "nan")
-    result = 3
-  elif buf[n-1] == 'F':
-    if buf[0] == '-':
-      writeToBuffer(buf, "-inf")
-      result = 4
-    else:
-      writeToBuffer(buf, "inf")
-      result = 3
-
-proc writeFloatToBuffer*(buf: var array[65, char]; value: BiggestFloat | float32): int {.inline.} =
-  when defined(nimPreviewFloatRoundtrip):
-    writeFloatToBufferRoundtrip(buf, value)
-  else:
-    writeFloatToBufferSprintf(buf, value)
-
-proc addFloatRoundtrip*(result: var string; x: float | float32) =
-  when nimvm:
-    doAssert false
-  else:
-    var buffer {.noinit.}: array[65, char]
-    let n = writeFloatToBufferRoundtrip(buffer, x)
-    result.addCstringN(cstring(buffer[0].addr), n)
-
-proc addFloatSprintf*(result: var string; x: float) =
-  when nimvm:
-    doAssert false
-  else:
-    var buffer {.noinit.}: array[65, char]
-    let n = writeFloatToBufferSprintf(buffer, x)
-    result.addCstringN(cstring(buffer[0].addr), n)
-
-proc nimFloatToString(a: float): cstring =
-  ## ensures the result doesn't print like an integer, i.e. return 2.0, not 2
-  # print `-0.0` properly
-  asm """
-    function nimOnlyDigitsOrMinus(n) {
-      return n.toString().match(/^-?\d+$/);
-    }
-    if (Number.isSafeInteger(`a`))
-      `result` = `a` === 0 && 1 / `a` < 0 ? "-0.0" : `a`+".0"
-    else {
-      `result` = `a`+""
-      if(nimOnlyDigitsOrMinus(`result`)){
-        `result` = `a`+".0"
-      }
-    }
-  """
-
-proc addFloat*(result: var string; x: float | float32) {.inline.} =
-  ## Converts float to its string representation and appends it to `result`.
-  runnableExamples:
-    var
-      s = "foo:"
-      b = 45.67
-    s.addFloat(45.67)
-    assert s == "foo:45.67"
-  template impl =
-    when defined(nimPreviewFloatRoundtrip):
-      addFloatRoundtrip(result, x)
-    else:
-      addFloatSprintf(result, x)
-  when defined(js):
-    when nimvm: impl()
-    else:
-      result.add nimFloatToString(x)
-  else: impl()
+when not defined(nimPreviewSlimSystem):
+  import std/formatfloat
+  export formatfloat
+  {.deprecated: "use `std/formatfloat`".}
+else:
+  {.error: "use `std/formatfloat`".}