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/*
* Phusion Passenger - https://www.phusionpassenger.com/
* Copyright (c) 2015-2017 Phusion Holding B.V.
*
* "Passenger", "Phusion Passenger" and "Union Station" are registered
* trademarks of Phusion Holding B.V.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef _PASSENGER_FAST_STRING_STREAM_H_
#define _PASSENGER_FAST_STRING_STREAM_H_
#include <ostream>
#include <sstream>
#include <string>
#include <new>
#include <cstdlib>
#include <boost/cstdint.hpp>
#include <boost/static_assert.hpp>
#include <oxt/macros.hpp>
namespace Passenger {
using namespace std;
/**
* An std::streambuf-compatible string buffer. It's similar to std::stringbuf,
* with a few optimizations:
*
* - It uses an in-place storage area as long as the amount of data written
* fits inside.
* - It allows direct read-only access to the storage area, in order to avoid
* copying data.
*/
template<size_t staticCapacity = 1024>
class FastStdStringBuf: public streambuf {
public:
typedef char char_type;
typedef char_traits<char> traits_type;
typedef traits_type::int_type int_type;
typedef traits_type::pos_type pos_type;
typedef traits_type::off_type off_type;
typedef string string_type;
// Ensures that power-of-two doubling of staticCapacity works.
BOOST_STATIC_ASSERT(staticCapacity >= 4);
private:
mutable char_type *bufend;
size_t dynamicCapacity;
union {
char staticBuffer[staticCapacity];
char *dynamicBuffer;
} u;
bool usingStaticBuffer() const {
return dynamicCapacity == 0;
}
boost::uint32_t nextPowerOf2(boost::uint32_t v) const {
v--;
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
v++;
return v;
}
protected:
virtual int_type overflow(int_type ch = traits_type::eof()) {
size_t oldSize = size();
size_t newDynamicCapacity;
char *newDynamicBuffer;
if (usingStaticBuffer()) {
newDynamicCapacity = nextPowerOf2(2 * staticCapacity);
newDynamicBuffer = (char *) malloc(newDynamicCapacity);
if (OXT_UNLIKELY(newDynamicBuffer == NULL)) {
return traits_type::eof();
}
memcpy(newDynamicBuffer, u.staticBuffer, oldSize);
} else {
newDynamicCapacity = 2 * dynamicCapacity;
newDynamicBuffer = (char *) realloc(u.dynamicBuffer, newDynamicCapacity);
if (OXT_UNLIKELY(newDynamicBuffer == NULL)) {
return traits_type::eof();
}
}
dynamicCapacity = newDynamicCapacity;
u.dynamicBuffer = newDynamicBuffer;
setp(u.dynamicBuffer, u.dynamicBuffer + dynamicCapacity);
if (traits_type::eq_int_type(ch, traits_type::eof())) {
pbump(oldSize);
} else {
u.dynamicBuffer[oldSize] = ch;
pbump(oldSize + 1);
}
return traits_type::not_eof(ch);
}
public:
FastStdStringBuf(unsigned int initialCapacity = 0) {
if (initialCapacity <= staticCapacity) {
dynamicCapacity = 0;
setp(u.staticBuffer, u.staticBuffer + staticCapacity);
} else {
dynamicCapacity = nextPowerOf2(initialCapacity);
u.dynamicBuffer = (char *) malloc(dynamicCapacity);
if (u.dynamicBuffer == NULL) {
throw std::bad_alloc();
}
setp(u.dynamicBuffer, u.dynamicBuffer + dynamicCapacity);
}
}
~FastStdStringBuf() {
if (!usingStaticBuffer()) {
free(u.dynamicBuffer);
}
}
const char *data() const {
return pbase();
}
size_t size() const {
return pptr() - pbase();
}
size_t capacity() const {
if (usingStaticBuffer()) {
return staticCapacity;
} else {
return dynamicCapacity;
}
}
};
/**
* An std::ostream-compatible output stream. It's similar to std::stringstream,
* with a few optimizations:
*
* - It uses an in-place storage area as long as the amount of data written
* fits inside.
* - It allows direct read-only access to the storage area, in order to avoid
* copying data.
*
* This class is implemented using FastStdStringBuf.
*/
#ifndef _PASSENGER_FAST_STRING_STREAM_FORWARD_DECLARED_
#define _PASSENGER_FAST_STRING_STREAM_FORWARD_DECLARED_
template<size_t staticCapacity = 1024>
#else
template<size_t staticCapacity>
#endif
class FastStringStream: public FastStdStringBuf<staticCapacity>, public ostream {
public:
FastStringStream(unsigned int initialCapacity = 0)
: FastStdStringBuf<staticCapacity>(initialCapacity),
ostream(this)
{ }
};
} // namespace Passenger
#endif /* _PASSENGER_FAST_STRING_STREAM_H_ */
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