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#include "dtoa.hpp"
// Clang/C2 on Windows 64-bits can't parse rapidjson's dtoa
// and it was causing the compiler to crash.
#if !defined(_WINDOWS)
#include <rapidjson/internal/dtoa.h>
#endif
namespace mbgl {
namespace util {
#if !defined(_WINDOWS)
namespace {
// From https://github.com/miloyip/rapidjson/blob/master/include/rapidjson/internal/dtoa.h
char* Prettify(char* buffer, int length, int k) {
constexpr int maxDecimalPlaces = 324;
const int kk = length + k; // 10^(kk-1) <= v < 10^kk
if (0 <= k && kk <= 21) {
// 1234e7 -> 12340000000
for (int i = length; i < kk; i++)
buffer[i] = '0';
return &buffer[kk];
}
else if (0 < kk && kk <= 21) {
// 1234e-2 -> 12.34
std::memmove(&buffer[kk + 1], &buffer[kk], static_cast<size_t>(length - kk));
buffer[kk] = '.';
if (0 > k + maxDecimalPlaces) {
// When maxDecimalPlaces = 2, 1.2345 -> 1.23, 1.102 -> 1.1
// Remove extra trailing zeros (at least one) after truncation.
for (int i = kk + maxDecimalPlaces; i > kk + 1; i--)
if (buffer[i] != '0')
return &buffer[i + 1];
return &buffer[kk + 2]; // Reserve one zero
}
else
return &buffer[length + 1];
}
else if (-6 < kk && kk <= 0) {
// 1234e-6 -> 0.001234
const int offset = 2 - kk;
std::memmove(&buffer[offset], &buffer[0], static_cast<size_t>(length));
buffer[0] = '0';
buffer[1] = '.';
for (int i = 2; i < offset; i++)
buffer[i] = '0';
if (length - kk > maxDecimalPlaces) {
// When maxDecimalPlaces = 2, 0.123 -> 0.12, 0.102 -> 0.1
// Remove extra trailing zeros (at least one) after truncation.
for (int i = maxDecimalPlaces + 1; i > 2; i--)
if (buffer[i] != '0')
return &buffer[i + 1];
return &buffer[3]; // Reserve one zero
}
else
return &buffer[length + offset];
}
else if (kk < -maxDecimalPlaces) {
// Truncate to zero
buffer[0] = '0';
return &buffer[1];
}
else if (length == 1) {
// 1e30
buffer[1] = 'e';
return rapidjson::internal::WriteExponent(kk - 1, &buffer[2]);
}
else {
// 1234e30 -> 1.234e33
std::memmove(&buffer[2], &buffer[1], static_cast<size_t>(length - 1));
buffer[1] = '.';
buffer[length + 1] = 'e';
return rapidjson::internal::WriteExponent(kk - 1, &buffer[0 + length + 2]);
}
}
} // namespace
char* dtoa(double value, char* buffer) {
rapidjson::internal::Double d(value);
if (d.IsZero()) {
if (d.Sign())
*buffer++ = '-'; // -0.0, Issue #289
buffer[0] = '0';
return &buffer[1];
}
else {
if (value < 0) {
*buffer++ = '-';
value = -value;
}
int length, K;
rapidjson::internal::Grisu2(value, buffer, &length, &K);
return Prettify(buffer, length, K);
}
}
std::string dtoa(double value) {
std::string data;
data.resize(25);
auto end = dtoa(value, const_cast<char*>(data.data()));
data.resize(end - data.data());
return data;
}
#else
std::string dtoa(double value) {
return std::to_string(value);
}
#endif
} // namespace util
} // namespace mbgl
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