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GenericReader: simplify local stream copy optimization

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rapidjson.h:
 * StreamLocalCopy: add default argument to copy optimization selector
   based on StreamTraits of Stream parameter
 * drop operator->, operator*
 * make Stream (reference) member public
 * drop empty destructor

reader.h:
 * add local references, initialized from "copy"
   (reverts algorithmic bodies back to plain 's.xx()')
This commit is contained in:
Philipp A. Hartmann 2014-07-02 20:51:10 +02:00
parent ebbfaf1c13
commit f6903f79d4
2 changed files with 60 additions and 61 deletions
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23
include/rapidjson/rapidjson.h
View File

@ -209,36 +209,29 @@ struct StreamTraits {
enum { copyOptimization = 0 };
};
template<typename Stream, bool>
template<typename Stream, bool = StreamTraits<Stream>::copyOptimization>
class StreamLocalCopy;
template<typename Stream>
class StreamLocalCopy<Stream, 1> {
public:
StreamLocalCopy(Stream& original) : original_(original), s_(original) {}
~StreamLocalCopy() { original_ = s_; }
Stream* operator->() { return &s_; }
Stream& operator*() { return s_; }
StreamLocalCopy(Stream& original) : s(original), original_(original) {}
~StreamLocalCopy() { original_ = s; }
Stream s; //!< copy
private:
StreamLocalCopy& operator=(const StreamLocalCopy&);
StreamLocalCopy& operator=(const StreamLocalCopy&) /* = delete */;
Stream& original_;
Stream s_;
};
template<typename Stream>
class StreamLocalCopy<Stream, 0> {
public:
StreamLocalCopy(Stream& original) : s_(original) {}
~StreamLocalCopy() {}
Stream* operator->() { return &s_; }
Stream& operator*() { return s_; }
StreamLocalCopy(Stream& original) : s(original) {}
Stream& s; //!< reference
private:
StreamLocalCopy& operator=(const StreamLocalCopy&);
Stream& s_;
StreamLocalCopy& operator=(const StreamLocalCopy&) /* = delete */;
};
//! Put N copies of a character to a stream.

98
include/rapidjson/reader.h
View File

@ -135,9 +135,11 @@ struct BaseReaderHandler {
*/
template<typename InputStream>
void SkipWhitespace(InputStream& is) {
StreamLocalCopy<InputStream, StreamTraits<InputStream>::copyOptimization> s(is);
while (s->Peek() == ' ' || s->Peek() == '\n' || s->Peek() == '\r' || s->Peek() == '\t')
s->Take();
StreamLocalCopy<InputStream> copy(is);
InputStream& s(copy.s);
while (s.Peek() == ' ' || s.Peek() == '\n' || s.Peek() == '\r' || s.Peek() == '\t')
s.Take();
}
#ifdef RAPIDJSON_SSE42
@ -448,19 +450,21 @@ private:
// Parse string and generate String event. Different code paths for kParseInsituFlag.
template<unsigned parseFlags, typename InputStream, typename Handler>
void ParseString(InputStream& is, Handler& handler) {
StreamLocalCopy<InputStream, StreamTraits<InputStream>::copyOptimization> s(is);
StreamLocalCopy<InputStream> copy(is);
InputStream& s(copy.s);
if (parseFlags & kParseInsituFlag) {
Ch *head = s->PutBegin();
ParseStringToStream<parseFlags, SourceEncoding, SourceEncoding>(*s, *s);
Ch *head = s.PutBegin();
ParseStringToStream<parseFlags, SourceEncoding, SourceEncoding>(s, s);
if (HasParseError())
return;
size_t length = s->PutEnd(head) - 1;
size_t length = s.PutEnd(head) - 1;
RAPIDJSON_ASSERT(length <= 0xFFFFFFFF);
handler.String((typename TargetEncoding::Ch*)head, SizeType(length), false);
}
else {
StackStream stackStream(stack_);
ParseStringToStream<parseFlags, SourceEncoding, TargetEncoding>(*s, stackStream);
ParseStringToStream<parseFlags, SourceEncoding, TargetEncoding>(s, stackStream);
if (HasParseError())
return;
handler.String(stack_.template Pop<typename TargetEncoding::Ch>(stackStream.length_), stackStream.length_ - 1, true);
@ -527,43 +531,45 @@ private:
template<unsigned parseFlags, typename InputStream, typename Handler>
void ParseNumber(InputStream& is, Handler& handler) {
StreamLocalCopy<InputStream, StreamTraits<InputStream>::copyOptimization> s(is);
StreamLocalCopy<InputStream> copy(is);
InputStream& s(copy.s);
// Parse minus
bool minus = false;
if (s->Peek() == '-') {
if (s.Peek() == '-') {
minus = true;
s->Take();
s.Take();
}
// Parse int: zero / ( digit1-9 *DIGIT )
unsigned i;
bool try64bit = false;
if (s->Peek() == '0') {
if (s.Peek() == '0') {
i = 0;
s->Take();
s.Take();
}
else if (s->Peek() >= '1' && s->Peek() <= '9') {
i = static_cast<unsigned>(s->Take() - '0');
else if (s.Peek() >= '1' && s.Peek() <= '9') {
i = static_cast<unsigned>(s.Take() - '0');
if (minus)
while (s->Peek() >= '0' && s->Peek() <= '9') {
while (s.Peek() >= '0' && s.Peek() <= '9') {
if (i >= 214748364) { // 2^31 = 2147483648
if (i != 214748364 || s->Peek() > '8') {
if (i != 214748364 || s.Peek() > '8') {
try64bit = true;
break;
}
}
i = i * 10 + static_cast<unsigned>(s->Take() - '0');
i = i * 10 + static_cast<unsigned>(s.Take() - '0');
}
else
while (s->Peek() >= '0' && s->Peek() <= '9') {
while (s.Peek() >= '0' && s.Peek() <= '9') {
if (i >= 429496729) { // 2^32 - 1 = 4294967295
if (i != 429496729 || s->Peek() > '5') {
if (i != 429496729 || s.Peek() > '5') {
try64bit = true;
break;
}
}
i = i * 10 + static_cast<unsigned>(s->Take() - '0');
i = i * 10 + static_cast<unsigned>(s.Take() - '0');
}
}
else
@ -575,22 +581,22 @@ private:
if (try64bit) {
i64 = i;
if (minus)
while (s->Peek() >= '0' && s->Peek() <= '9') {
while (s.Peek() >= '0' && s.Peek() <= '9') {
if (i64 >= UINT64_C(922337203685477580)) // 2^63 = 9223372036854775808
if (i64 != UINT64_C(922337203685477580) || s->Peek() > '8') {
if (i64 != UINT64_C(922337203685477580) || s.Peek() > '8') {
useDouble = true;
break;
}
i64 = i64 * 10 + static_cast<unsigned>(s->Take() - '0');
i64 = i64 * 10 + static_cast<unsigned>(s.Take() - '0');
}
else
while (s->Peek() >= '0' && s->Peek() <= '9') {
while (s.Peek() >= '0' && s.Peek() <= '9') {
if (i64 >= UINT64_C(1844674407370955161)) // 2^64 - 1 = 18446744073709551615
if (i64 != UINT64_C(1844674407370955161) || s->Peek() > '5') {
if (i64 != UINT64_C(1844674407370955161) || s.Peek() > '5') {
useDouble = true;
break;
}
i64 = i64 * 10 + static_cast<unsigned>(s->Take() - '0');
i64 = i64 * 10 + static_cast<unsigned>(s.Take() - '0');
}
}
@ -598,59 +604,59 @@ private:
double d = 0.0;
if (useDouble) {
d = (double)i64;
while (s->Peek() >= '0' && s->Peek() <= '9') {
while (s.Peek() >= '0' && s.Peek() <= '9') {
if (d >= 1E307)
RAPIDJSON_PARSE_ERROR(kParesErrorNumberTooBig, is.Tell());
d = d * 10 + (s->Take() - '0');
d = d * 10 + (s.Take() - '0');
}
}
// Parse frac = decimal-point 1*DIGIT
int expFrac = 0;
if (s->Peek() == '.') {
if (s.Peek() == '.') {
if (!useDouble) {
d = try64bit ? (double)i64 : (double)i;
useDouble = true;
}
s->Take();
s.Take();
if (s->Peek() >= '0' && s->Peek() <= '9') {
d = d * 10 + (s->Take() - '0');
if (s.Peek() >= '0' && s.Peek() <= '9') {
d = d * 10 + (s.Take() - '0');
--expFrac;
}
else
RAPIDJSON_PARSE_ERROR(kParseErrorNumberMissFraction, is.Tell());
while (s->Peek() >= '0' && s->Peek() <= '9') {
while (s.Peek() >= '0' && s.Peek() <= '9') {
if (expFrac > -16) {
d = d * 10 + (s->Peek() - '0');
d = d * 10 + (s.Peek() - '0');
--expFrac;
}
s->Take();
s.Take();
}
}
// Parse exp = e [ minus / plus ] 1*DIGIT
int exp = 0;
if (s->Peek() == 'e' || s->Peek() == 'E') {
if (s.Peek() == 'e' || s.Peek() == 'E') {
if (!useDouble) {
d = try64bit ? (double)i64 : (double)i;
useDouble = true;
}
s->Take();
s.Take();
bool expMinus = false;
if (s->Peek() == '+')
s->Take();
else if (s->Peek() == '-') {
s->Take();
if (s.Peek() == '+')
s.Take();
else if (s.Peek() == '-') {
s.Take();
expMinus = true;
}
if (s->Peek() >= '0' && s->Peek() <= '9') {
exp = s->Take() - '0';
while (s->Peek() >= '0' && s->Peek() <= '9') {
exp = exp * 10 + (s->Take() - '0');
if (s.Peek() >= '0' && s.Peek() <= '9') {
exp = s.Take() - '0';
while (s.Peek() >= '0' && s.Peek() <= '9') {
exp = exp * 10 + (s.Take() - '0');
if (exp > 308)
RAPIDJSON_PARSE_ERROR(kParesErrorNumberTooBig, is.Tell());
}