icuSources/i18n/double-conversion-cached-powers.cpp

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   3 //
   4 // From the double-conversion library. Original license:
   5 //
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  32
  33 // ICU PATCH: ifdef around UCONFIG_NO_FORMATTING
  34 #include "unicode/utypes.h"
  35 #if !UCONFIG_NO_FORMATTING
  36
  37 #include <climits>
  38 #include <cmath>
  39 #include <cstdarg>
  40
  41 // ICU PATCH: Customize header file paths for ICU.
  42
  43 #include "double-conversion-utils.h"
  44
  45 #include "double-conversion-cached-powers.h"
  46
  47 // ICU PATCH: Wrap in ICU namespace
  48 U_NAMESPACE_BEGIN
  49
  50 namespace double_conversion {
  51
  52 struct CachedPower {
  53   uint64_t significand;
  54   int16_t binary_exponent;
  55   int16_t decimal_exponent;
  56 };
  57
  58 static const CachedPower kCachedPowers[] = {
  59   {UINT64_2PART_C(0xfa8fd5a0, 081c0288), -1220, -348},
  60   {UINT64_2PART_C(0xbaaee17f, a23ebf76), -1193, -340},
  61   {UINT64_2PART_C(0x8b16fb20, 3055ac76), -1166, -332},
  62   {UINT64_2PART_C(0xcf42894a, 5dce35ea), -1140, -324},
  63   {UINT64_2PART_C(0x9a6bb0aa, 55653b2d), -1113, -316},
  64   {UINT64_2PART_C(0xe61acf03, 3d1a45df), -1087, -308},
  65   {UINT64_2PART_C(0xab70fe17, c79ac6ca), -1060, -300},
  66   {UINT64_2PART_C(0xff77b1fc, bebcdc4f), -1034, -292},
  67   {UINT64_2PART_C(0xbe5691ef, 416bd60c), -1007, -284},
  68   {UINT64_2PART_C(0x8dd01fad, 907ffc3c), -980, -276},
  69   {UINT64_2PART_C(0xd3515c28, 31559a83), -954, -268},
  70   {UINT64_2PART_C(0x9d71ac8f, ada6c9b5), -927, -260},
  71   {UINT64_2PART_C(0xea9c2277, 23ee8bcb), -901, -252},
  72   {UINT64_2PART_C(0xaecc4991, 4078536d), -874, -244},
  73   {UINT64_2PART_C(0x823c1279, 5db6ce57), -847, -236},
  74   {UINT64_2PART_C(0xc2109436, 4dfb5637), -821, -228},
  75   {UINT64_2PART_C(0x9096ea6f, 3848984f), -794, -220},
  76   {UINT64_2PART_C(0xd77485cb, 25823ac7), -768, -212},
  77   {UINT64_2PART_C(0xa086cfcd, 97bf97f4), -741, -204},
  78   {UINT64_2PART_C(0xef340a98, 172aace5), -715, -196},
  79   {UINT64_2PART_C(0xb23867fb, 2a35b28e), -688, -188},
  80   {UINT64_2PART_C(0x84c8d4df, d2c63f3b), -661, -180},
  81   {UINT64_2PART_C(0xc5dd4427, 1ad3cdba), -635, -172},
  82   {UINT64_2PART_C(0x936b9fce, bb25c996), -608, -164},
  83   {UINT64_2PART_C(0xdbac6c24, 7d62a584), -582, -156},
  84   {UINT64_2PART_C(0xa3ab6658, 0d5fdaf6), -555, -148},
  85   {UINT64_2PART_C(0xf3e2f893, dec3f126), -529, -140},
  86   {UINT64_2PART_C(0xb5b5ada8, aaff80b8), -502, -132},
  87   {UINT64_2PART_C(0x87625f05, 6c7c4a8b), -475, -124},
  88   {UINT64_2PART_C(0xc9bcff60, 34c13053), -449, -116},
  89   {UINT64_2PART_C(0x964e858c, 91ba2655), -422, -108},
  90   {UINT64_2PART_C(0xdff97724, 70297ebd), -396, -100},
  91   {UINT64_2PART_C(0xa6dfbd9f, b8e5b88f), -369, -92},
  92   {UINT64_2PART_C(0xf8a95fcf, 88747d94), -343, -84},
  93   {UINT64_2PART_C(0xb9447093, 8fa89bcf), -316, -76},
  94   {UINT64_2PART_C(0x8a08f0f8, bf0f156b), -289, -68},
  95   {UINT64_2PART_C(0xcdb02555, 653131b6), -263, -60},
  96   {UINT64_2PART_C(0x993fe2c6, d07b7fac), -236, -52},
  97   {UINT64_2PART_C(0xe45c10c4, 2a2b3b06), -210, -44},
  98   {UINT64_2PART_C(0xaa242499, 697392d3), -183, -36},
  99   {UINT64_2PART_C(0xfd87b5f2, 8300ca0e), -157, -28},
 100   {UINT64_2PART_C(0xbce50864, 92111aeb), -130, -20},
 101   {UINT64_2PART_C(0x8cbccc09, 6f5088cc), -103, -12},
 102   {UINT64_2PART_C(0xd1b71758, e219652c), -77, -4},
 103   {UINT64_2PART_C(0x9c400000, 00000000), -50, 4},
 104   {UINT64_2PART_C(0xe8d4a510, 00000000), -24, 12},
 105   {UINT64_2PART_C(0xad78ebc5, ac620000), 3, 20},
 106   {UINT64_2PART_C(0x813f3978, f8940984), 30, 28},
 107   {UINT64_2PART_C(0xc097ce7b, c90715b3), 56, 36},
 108   {UINT64_2PART_C(0x8f7e32ce, 7bea5c70), 83, 44},
 109   {UINT64_2PART_C(0xd5d238a4, abe98068), 109, 52},
 110   {UINT64_2PART_C(0x9f4f2726, 179a2245), 136, 60},
 111   {UINT64_2PART_C(0xed63a231, d4c4fb27), 162, 68},
 112   {UINT64_2PART_C(0xb0de6538, 8cc8ada8), 189, 76},
 113   {UINT64_2PART_C(0x83c7088e, 1aab65db), 216, 84},
 114   {UINT64_2PART_C(0xc45d1df9, 42711d9a), 242, 92},
 115   {UINT64_2PART_C(0x924d692c, a61be758), 269, 100},
 116   {UINT64_2PART_C(0xda01ee64, 1a708dea), 295, 108},
 117   {UINT64_2PART_C(0xa26da399, 9aef774a), 322, 116},
 118   {UINT64_2PART_C(0xf209787b, b47d6b85), 348, 124},
 119   {UINT64_2PART_C(0xb454e4a1, 79dd1877), 375, 132},
 120   {UINT64_2PART_C(0x865b8692, 5b9bc5c2), 402, 140},
 121   {UINT64_2PART_C(0xc83553c5, c8965d3d), 428, 148},
 122   {UINT64_2PART_C(0x952ab45c, fa97a0b3), 455, 156},
 123   {UINT64_2PART_C(0xde469fbd, 99a05fe3), 481, 164},
 124   {UINT64_2PART_C(0xa59bc234, db398c25), 508, 172},
 125   {UINT64_2PART_C(0xf6c69a72, a3989f5c), 534, 180},
 126   {UINT64_2PART_C(0xb7dcbf53, 54e9bece), 561, 188},
 127   {UINT64_2PART_C(0x88fcf317, f22241e2), 588, 196},
 128   {UINT64_2PART_C(0xcc20ce9b, d35c78a5), 614, 204},
 129   {UINT64_2PART_C(0x98165af3, 7b2153df), 641, 212},
 130   {UINT64_2PART_C(0xe2a0b5dc, 971f303a), 667, 220},
 131   {UINT64_2PART_C(0xa8d9d153, 5ce3b396), 694, 228},
 132   {UINT64_2PART_C(0xfb9b7cd9, a4a7443c), 720, 236},
 133   {UINT64_2PART_C(0xbb764c4c, a7a44410), 747, 244},
 134   {UINT64_2PART_C(0x8bab8eef, b6409c1a), 774, 252},
 135   {UINT64_2PART_C(0xd01fef10, a657842c), 800, 260},
 136   {UINT64_2PART_C(0x9b10a4e5, e9913129), 827, 268},
 137   {UINT64_2PART_C(0xe7109bfb, a19c0c9d), 853, 276},
 138   {UINT64_2PART_C(0xac2820d9, 623bf429), 880, 284},
 139   {UINT64_2PART_C(0x80444b5e, 7aa7cf85), 907, 292},
 140   {UINT64_2PART_C(0xbf21e440, 03acdd2d), 933, 300},
 141   {UINT64_2PART_C(0x8e679c2f, 5e44ff8f), 960, 308},
 142   {UINT64_2PART_C(0xd433179d, 9c8cb841), 986, 316},
 143   {UINT64_2PART_C(0x9e19db92, b4e31ba9), 1013, 324},
 144   {UINT64_2PART_C(0xeb96bf6e, badf77d9), 1039, 332},
 145   {UINT64_2PART_C(0xaf87023b, 9bf0ee6b), 1066, 340},
 146 };
 147
 148 static const int kCachedPowersOffset = 348;  // -1 * the first decimal_exponent.
 149 static const double kD_1_LOG2_10 = 0.30102999566398114;  //  1 / lg(10)
 150 // Difference between the decimal exponents in the table above.
 151 const int PowersOfTenCache::kDecimalExponentDistance = 8;
 152 const int PowersOfTenCache::kMinDecimalExponent = -348;
 153 const int PowersOfTenCache::kMaxDecimalExponent = 340;
 154
 155 void PowersOfTenCache::GetCachedPowerForBinaryExponentRange(
 156     int min_exponent,
 157     int max_exponent,
 158     DiyFp* power,
 159     int* decimal_exponent) {
 160   int kQ = DiyFp::kSignificandSize;
 161   double k = ceil((min_exponent + kQ - 1) * kD_1_LOG2_10);
 162   int foo = kCachedPowersOffset;
 163   int index =
 164       (foo + static_cast<int>(k) - 1) / kDecimalExponentDistance + 1;
 165   ASSERT(0 <= index && index < static_cast<int>(ARRAY_SIZE(kCachedPowers)));
 166   CachedPower cached_power = kCachedPowers[index];
 167   ASSERT(min_exponent <= cached_power.binary_exponent);
 168   (void) max_exponent;  // Mark variable as used.
 169   ASSERT(cached_power.binary_exponent <= max_exponent);
 170   *decimal_exponent = cached_power.decimal_exponent;
 171   *power = DiyFp(cached_power.significand, cached_power.binary_exponent);
 172 }
 173
 174
 175 void PowersOfTenCache::GetCachedPowerForDecimalExponent(int requested_exponent,
 176                                                         DiyFp* power,
 177                                                         int* found_exponent) {
 178   ASSERT(kMinDecimalExponent <= requested_exponent);
 179   ASSERT(requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance);
 180   int index =
 181       (requested_exponent + kCachedPowersOffset) / kDecimalExponentDistance;
 182   CachedPower cached_power = kCachedPowers[index];
 183   *power = DiyFp(cached_power.significand, cached_power.binary_exponent);
 184   *found_exponent = cached_power.decimal_exponent;
 185   ASSERT(*found_exponent <= requested_exponent);
 186   ASSERT(requested_exponent < *found_exponent + kDecimalExponentDistance);
 187 }
 188
 189 }  // namespace double_conversion
 190
 191 // ICU PATCH: Close ICU namespace
 192 U_NAMESPACE_END
 193 #endif // ICU PATCH: close #if !UCONFIG_NO_FORMATTING