double-conversion-bignum-dtoa.h 4.7 KB

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  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.
  17. // * Neither the name of Google Inc. nor the names of its
  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
  23. // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24. // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25. // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26. // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27. // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28. // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29. // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30. // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31. // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32. // ICU PATCH: ifdef around UCONFIG_NO_FORMATTING
  33. #include "unicode/utypes.h"
  34. #if !UCONFIG_NO_FORMATTING
  35. #ifndef DOUBLE_CONVERSION_BIGNUM_DTOA_H_
  36. #define DOUBLE_CONVERSION_BIGNUM_DTOA_H_
  37. // ICU PATCH: Customize header file paths for ICU.
  38. #include "double-conversion-utils.h"
  39. // ICU PATCH: Wrap in ICU namespace
  40. U_NAMESPACE_BEGIN
  41. namespace double_conversion {
  42. enum BignumDtoaMode {
  43. // Return the shortest correct representation.
  44. // For example the output of 0.299999999999999988897 is (the less accurate but
  45. // correct) 0.3.
  46. BIGNUM_DTOA_SHORTEST,
  47. // Same as BIGNUM_DTOA_SHORTEST but for single-precision floats.
  48. BIGNUM_DTOA_SHORTEST_SINGLE,
  49. // Return a fixed number of digits after the decimal point.
  50. // For instance fixed(0.1, 4) becomes 0.1000
  51. // If the input number is big, the output will be big.
  52. BIGNUM_DTOA_FIXED,
  53. // Return a fixed number of digits, no matter what the exponent is.
  54. BIGNUM_DTOA_PRECISION
  55. };
  56. // Converts the given double 'v' to ascii.
  57. // The result should be interpreted as buffer * 10^(point-length).
  58. // The buffer will be null-terminated.
  59. //
  60. // The input v must be > 0 and different from NaN, and Infinity.
  61. //
  62. // The output depends on the given mode:
  63. // - SHORTEST: produce the least amount of digits for which the internal
  64. // identity requirement is still satisfied. If the digits are printed
  65. // (together with the correct exponent) then reading this number will give
  66. // 'v' again. The buffer will choose the representation that is closest to
  67. // 'v'. If there are two at the same distance, than the number is round up.
  68. // In this mode the 'requested_digits' parameter is ignored.
  69. // - FIXED: produces digits necessary to print a given number with
  70. // 'requested_digits' digits after the decimal point. The produced digits
  71. // might be too short in which case the caller has to fill the gaps with '0's.
  72. // Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2.
  73. // Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns
  74. // buffer="2", point=0.
  75. // Note: the length of the returned buffer has no meaning wrt the significance
  76. // of its digits. That is, just because it contains '0's does not mean that
  77. // any other digit would not satisfy the internal identity requirement.
  78. // - PRECISION: produces 'requested_digits' where the first digit is not '0'.
  79. // Even though the length of produced digits usually equals
  80. // 'requested_digits', the function is allowed to return fewer digits, in
  81. // which case the caller has to fill the missing digits with '0's.
  82. // Halfway cases are again rounded up.
  83. // 'BignumDtoa' expects the given buffer to be big enough to hold all digits
  84. // and a terminating null-character.
  85. void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits,
  86. Vector<char> buffer, int* length, int* point);
  87. } // namespace double_conversion
  88. // ICU PATCH: Close ICU namespace
  89. U_NAMESPACE_END
  90. #endif // DOUBLE_CONVERSION_BIGNUM_DTOA_H_
  91. #endif // ICU PATCH: close #if !UCONFIG_NO_FORMATTING