in rapidjson/internal/strtod.h [224:264]
inline double StrtodFullPrecision(double d, int p, const char* decimals, size_t length, size_t decimalPosition, int exp) {
RAPIDJSON_ASSERT(d >= 0.0);
RAPIDJSON_ASSERT(length >= 1);
double result;
if (StrtodFast(d, p, &result))
return result;
// Trim leading zeros
while (*decimals == '0' && length > 1) {
length--;
decimals++;
decimalPosition--;
}
// Trim trailing zeros
while (decimals[length - 1] == '0' && length > 1) {
length--;
decimalPosition--;
exp++;
}
// Trim right-most digits
const int kMaxDecimalDigit = 780;
if (static_cast<int>(length) > kMaxDecimalDigit) {
int delta = (static_cast<int>(length) - kMaxDecimalDigit);
exp += delta;
decimalPosition -= static_cast<unsigned>(delta);
length = kMaxDecimalDigit;
}
// If too small, underflow to zero
if (int(length) + exp < -324)
return 0.0;
if (StrtodDiyFp(decimals, length, decimalPosition, exp, &result))
return result;
// Use approximation from StrtodDiyFp and make adjustment with BigInteger comparison
return StrtodBigInteger(result, decimals, length, decimalPosition, exp);
}