in include/rapidjson/reader.h [1456:1720]
void ParseNumber(InputStream& is, Handler& handler) {
internal::StreamLocalCopy<InputStream> copy(is);
NumberStream<InputStream,
((parseFlags & kParseNumbersAsStringsFlag) != 0) ?
((parseFlags & kParseInsituFlag) == 0) :
((parseFlags & kParseFullPrecisionFlag) != 0),
(parseFlags & kParseNumbersAsStringsFlag) != 0 &&
(parseFlags & kParseInsituFlag) == 0> s(*this, copy.s);
size_t startOffset = s.Tell();
double d = 0.0;
bool useNanOrInf = false;
// Parse minus
bool minus = Consume(s, '-');
// Parse int: zero / ( digit1-9 *DIGIT )
unsigned i = 0;
uint64_t i64 = 0;
bool use64bit = false;
int significandDigit = 0;
if (RAPIDJSON_UNLIKELY(s.Peek() == '0')) {
i = 0;
s.TakePush();
}
else if (RAPIDJSON_LIKELY(s.Peek() >= '1' && s.Peek() <= '9')) {
i = static_cast<unsigned>(s.TakePush() - '0');
if (minus)
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
if (RAPIDJSON_UNLIKELY(i >= 214748364)) { // 2^31 = 2147483648
if (RAPIDJSON_LIKELY(i != 214748364 || s.Peek() > '8')) {
i64 = i;
use64bit = true;
break;
}
}
i = i * 10 + static_cast<unsigned>(s.TakePush() - '0');
significandDigit++;
}
else
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
if (RAPIDJSON_UNLIKELY(i >= 429496729)) { // 2^32 - 1 = 4294967295
if (RAPIDJSON_LIKELY(i != 429496729 || s.Peek() > '5')) {
i64 = i;
use64bit = true;
break;
}
}
i = i * 10 + static_cast<unsigned>(s.TakePush() - '0');
significandDigit++;
}
}
// Parse NaN or Infinity here
else if ((parseFlags & kParseNanAndInfFlag) && RAPIDJSON_LIKELY((s.Peek() == 'I' || s.Peek() == 'N'))) {
if (Consume(s, 'N')) {
if (Consume(s, 'a') && Consume(s, 'N')) {
d = std::numeric_limits<double>::quiet_NaN();
useNanOrInf = true;
}
}
else if (RAPIDJSON_LIKELY(Consume(s, 'I'))) {
if (Consume(s, 'n') && Consume(s, 'f')) {
d = (minus ? -std::numeric_limits<double>::infinity() : std::numeric_limits<double>::infinity());
useNanOrInf = true;
if (RAPIDJSON_UNLIKELY(s.Peek() == 'i' && !(Consume(s, 'i') && Consume(s, 'n')
&& Consume(s, 'i') && Consume(s, 't') && Consume(s, 'y')))) {
RAPIDJSON_PARSE_ERROR(kParseErrorValueInvalid, s.Tell());
}
}
}
if (RAPIDJSON_UNLIKELY(!useNanOrInf)) {
RAPIDJSON_PARSE_ERROR(kParseErrorValueInvalid, s.Tell());
}
}
else
RAPIDJSON_PARSE_ERROR(kParseErrorValueInvalid, s.Tell());
// Parse 64bit int
bool useDouble = false;
if (use64bit) {
if (minus)
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
if (RAPIDJSON_UNLIKELY(i64 >= RAPIDJSON_UINT64_C2(0x0CCCCCCC, 0xCCCCCCCC))) // 2^63 = 9223372036854775808
if (RAPIDJSON_LIKELY(i64 != RAPIDJSON_UINT64_C2(0x0CCCCCCC, 0xCCCCCCCC) || s.Peek() > '8')) {
d = static_cast<double>(i64);
useDouble = true;
break;
}
i64 = i64 * 10 + static_cast<unsigned>(s.TakePush() - '0');
significandDigit++;
}
else
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
if (RAPIDJSON_UNLIKELY(i64 >= RAPIDJSON_UINT64_C2(0x19999999, 0x99999999))) // 2^64 - 1 = 18446744073709551615
if (RAPIDJSON_LIKELY(i64 != RAPIDJSON_UINT64_C2(0x19999999, 0x99999999) || s.Peek() > '5')) {
d = static_cast<double>(i64);
useDouble = true;
break;
}
i64 = i64 * 10 + static_cast<unsigned>(s.TakePush() - '0');
significandDigit++;
}
}
// Force double for big integer
if (useDouble) {
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
if (RAPIDJSON_UNLIKELY(d >= 1.7976931348623157e307)) // DBL_MAX / 10.0
RAPIDJSON_PARSE_ERROR(kParseErrorNumberTooBig, startOffset);
d = d * 10 + (s.TakePush() - '0');
}
}
// Parse frac = decimal-point 1*DIGIT
int expFrac = 0;
size_t decimalPosition;
if (Consume(s, '.')) {
decimalPosition = s.Length();
if (RAPIDJSON_UNLIKELY(!(s.Peek() >= '0' && s.Peek() <= '9')))
RAPIDJSON_PARSE_ERROR(kParseErrorNumberMissFraction, s.Tell());
if (!useDouble) {
#if RAPIDJSON_64BIT
// Use i64 to store significand in 64-bit architecture
if (!use64bit)
i64 = i;
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
if (i64 > RAPIDJSON_UINT64_C2(0x1FFFFF, 0xFFFFFFFF)) // 2^53 - 1 for fast path
break;
else {
i64 = i64 * 10 + static_cast<unsigned>(s.TakePush() - '0');
--expFrac;
if (i64 != 0)
significandDigit++;
}
}
d = static_cast<double>(i64);
#else
// Use double to store significand in 32-bit architecture
d = static_cast<double>(use64bit ? i64 : i);
#endif
useDouble = true;
}
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
if (significandDigit < 17) {
d = d * 10.0 + (s.TakePush() - '0');
--expFrac;
if (RAPIDJSON_LIKELY(d > 0.0))
significandDigit++;
}
else
s.TakePush();
}
}
else
decimalPosition = s.Length(); // decimal position at the end of integer.
// Parse exp = e [ minus / plus ] 1*DIGIT
int exp = 0;
if (Consume(s, 'e') || Consume(s, 'E')) {
if (!useDouble) {
d = static_cast<double>(use64bit ? i64 : i);
useDouble = true;
}
bool expMinus = false;
if (Consume(s, '+'))
;
else if (Consume(s, '-'))
expMinus = true;
if (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
exp = static_cast<int>(s.Take() - '0');
if (expMinus) {
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
exp = exp * 10 + static_cast<int>(s.Take() - '0');
if (exp >= 214748364) { // Issue #313: prevent overflow exponent
while (RAPIDJSON_UNLIKELY(s.Peek() >= '0' && s.Peek() <= '9')) // Consume the rest of exponent
s.Take();
}
}
}
else { // positive exp
int maxExp = 308 - expFrac;
while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
exp = exp * 10 + static_cast<int>(s.Take() - '0');
if (RAPIDJSON_UNLIKELY(exp > maxExp))
RAPIDJSON_PARSE_ERROR(kParseErrorNumberTooBig, startOffset);
}
}
}
else
RAPIDJSON_PARSE_ERROR(kParseErrorNumberMissExponent, s.Tell());
if (expMinus)
exp = -exp;
}
// Finish parsing, call event according to the type of number.
bool cont = true;
if (parseFlags & kParseNumbersAsStringsFlag) {
if (parseFlags & kParseInsituFlag) {
s.Pop(); // Pop stack no matter if it will be used or not.
typename InputStream::Ch* head = is.PutBegin();
const size_t length = s.Tell() - startOffset;
RAPIDJSON_ASSERT(length <= 0xFFFFFFFF);
// unable to insert the \0 character here, it will erase the comma after this number
const typename TargetEncoding::Ch* const str = reinterpret_cast<typename TargetEncoding::Ch*>(head);
cont = handler.RawNumber(str, SizeType(length), false);
}
else {
SizeType numCharsToCopy = static_cast<SizeType>(s.Length());
StringStream srcStream(s.Pop());
StackStream<typename TargetEncoding::Ch> dstStream(stack_);
while (numCharsToCopy--) {
Transcoder<UTF8<>, TargetEncoding>::Transcode(srcStream, dstStream);
}
dstStream.Put('\0');
const typename TargetEncoding::Ch* str = dstStream.Pop();
const SizeType length = static_cast<SizeType>(dstStream.Length()) - 1;
cont = handler.RawNumber(str, SizeType(length), true);
}
}
else {
size_t length = s.Length();
const char* decimal = s.Pop(); // Pop stack no matter if it will be used or not.
if (useDouble) {
int p = exp + expFrac;
if (parseFlags & kParseFullPrecisionFlag)
d = internal::StrtodFullPrecision(d, p, decimal, length, decimalPosition, exp);
else
d = internal::StrtodNormalPrecision(d, p);
cont = handler.Double(minus ? -d : d);
}
else if (useNanOrInf) {
cont = handler.Double(d);
}
else {
if (use64bit) {
if (minus)
cont = handler.Int64(static_cast<int64_t>(~i64 + 1));
else
cont = handler.Uint64(i64);
}
else {
if (minus)
cont = handler.Int(static_cast<int32_t>(~i + 1));
else
cont = handler.Uint(i);
}
}
}
if (RAPIDJSON_UNLIKELY(!cont))
RAPIDJSON_PARSE_ERROR(kParseErrorTermination, startOffset);
}