icuSources/i18n/double-conversion-bignum-dtoa.h

   1 // © 2018 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 //
   4 // From the double-conversion library. Original license:
   5 //
   6 // Copyright 2010 the V8 project authors. All rights reserved.
   7 // Redistribution and use in source and binary forms, with or without
   8 // modification, are permitted provided that the following conditions are
   9 // met:
  10 //
  11 //     * Redistributions of source code must retain the above copyright
  12 //       notice, this list of conditions and the following disclaimer.
  13 //     * Redistributions in binary form must reproduce the above
  14 //       copyright notice, this list of conditions and the following
  15 //       disclaimer in the documentation and/or other materials provided
  16 //       with the distribution.
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  18 //       contributors may be used to endorse or promote products derived
  19 //       from this software without specific prior written permission.
  20 //
  21 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  31 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32
  33 // ICU PATCH: ifdef around UCONFIG_NO_FORMATTING
  34 #include "unicode/utypes.h"
  35 #if !UCONFIG_NO_FORMATTING
  36
  37 #ifndef DOUBLE_CONVERSION_BIGNUM_DTOA_H_
  38 #define DOUBLE_CONVERSION_BIGNUM_DTOA_H_
  39
  40 // ICU PATCH: Customize header file paths for ICU.
  41
  42 #include "double-conversion-utils.h"
  43
  44 // ICU PATCH: Wrap in ICU namespace
  45 U_NAMESPACE_BEGIN
  46
  47 namespace double_conversion {
  48
  49 enum BignumDtoaMode {
  50   // Return the shortest correct representation.
  51   // For example the output of 0.299999999999999988897 is (the less accurate but
  52   // correct) 0.3.
  53   BIGNUM_DTOA_SHORTEST,
  54   // Same as BIGNUM_DTOA_SHORTEST but for single-precision floats.
  55   BIGNUM_DTOA_SHORTEST_SINGLE,
  56   // Return a fixed number of digits after the decimal point.
  57   // For instance fixed(0.1, 4) becomes 0.1000
  58   // If the input number is big, the output will be big.
  59   BIGNUM_DTOA_FIXED,
  60   // Return a fixed number of digits, no matter what the exponent is.
  61   BIGNUM_DTOA_PRECISION
  62 };
  63
  64 // Converts the given double 'v' to ascii.
  65 // The result should be interpreted as buffer * 10^(point-length).
  66 // The buffer will be null-terminated.
  67 //
  68 // The input v must be > 0 and different from NaN, and Infinity.
  69 //
  70 // The output depends on the given mode:
  71 //  - SHORTEST: produce the least amount of digits for which the internal
  72 //   identity requirement is still satisfied. If the digits are printed
  73 //   (together with the correct exponent) then reading this number will give
  74 //   'v' again. The buffer will choose the representation that is closest to
  75 //   'v'. If there are two at the same distance, than the number is round up.
  76 //   In this mode the 'requested_digits' parameter is ignored.
  77 //  - FIXED: produces digits necessary to print a given number with
  78 //   'requested_digits' digits after the decimal point. The produced digits
  79 //   might be too short in which case the caller has to fill the gaps with '0's.
  80 //   Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2.
  81 //   Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns
  82 //     buffer="2", point=0.
  83 //   Note: the length of the returned buffer has no meaning wrt the significance
  84 //   of its digits. That is, just because it contains '0's does not mean that
  85 //   any other digit would not satisfy the internal identity requirement.
  86 //  - PRECISION: produces 'requested_digits' where the first digit is not '0'.
  87 //   Even though the length of produced digits usually equals
  88 //   'requested_digits', the function is allowed to return fewer digits, in
  89 //   which case the caller has to fill the missing digits with '0's.
  90 //   Halfway cases are again rounded up.
  91 // 'BignumDtoa' expects the given buffer to be big enough to hold all digits
  92 // and a terminating null-character.
  93 void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits,
  94                 Vector<char> buffer, int* length, int* point);
  95
  96 }  // namespace double_conversion
  97
  98 // ICU PATCH: Close ICU namespace
  99 U_NAMESPACE_END
 100
 101 #endif  // DOUBLE_CONVERSION_BIGNUM_DTOA_H_
 102 #endif // ICU PATCH: close #if !UCONFIG_NO_FORMATTING