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foundationdb/flow/Arena.h

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/*
* Arena.h
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FLOW_ARENA_H
#define FLOW_ARENA_H
#pragma once
#include "FastAlloc.h"
#include "FastRef.h"
#include "Error.h"
#include "Trace.h"
#include <algorithm>
#include <stdint.h>
#include <string>
#include <cstring>
#include <limits>
#include <set>
#include <type_traits>
// TrackIt is a zero-size class for tracking constructions, destructions, and assignments of instances
// of a class. Just inherit TrackIt<T> from T to enable tracking of construction and destruction of
// T, and use the TRACKIT_ASSIGN(rhs) macro in any operator= definitions to enable assignment tracking.
//
// TrackIt writes to standard output because the trace log isn't available early in execution
// so applying TrackIt to StringRef or VectorRef, for example, would a segfault using the trace log.
//
// The template parameter enables TrackIt to be inherited multiple times in the ancestry
// of a class without producing an "inaccessible due to ambiguity" error.
template<class T>
struct TrackIt {
typedef TrackIt<T> TrackItType;
// Put TRACKIT_ASSIGN into any operator= functions for which you want assignments tracked
#define TRACKIT_ASSIGN(o) *(TrackItType *)this = *(TrackItType *)&(o)
// The type name T is in the TrackIt output so that objects that inherit TrackIt multiple times
// can be tracked propertly, otherwise the create and delete addresses appear duplicative.
// This function returns just the string "T]" parsed from the __PRETTY_FUNCTION__ macro. There
// doesn't seem to be a better portable way to do this.
static const char * __trackit__type() {
const char *s = __PRETTY_FUNCTION__ + sizeof(__PRETTY_FUNCTION__);
while(*--s != '=');
return s + 2;
}
TrackIt() {
printf("TrackItCreate\t%s\t%p\t%s\n", __trackit__type(), this, platform::get_backtrace().c_str());
}
TrackIt(const TrackIt &o) : TrackIt() {}
TrackIt(const TrackIt &&o) : TrackIt() {}
TrackIt & operator=(const TrackIt &o) {
printf("TrackItAssigned\t%s\t%p<%p\t%s\n", __trackit__type(), this, &o, platform::get_backtrace().c_str());
return *this;
}
TrackIt & operator=(const TrackIt &&o) {
return *this = (const TrackIt &)o;
}
~TrackIt() {
printf("TrackItDestroy\t%s\t%p\n", __trackit__type(), this);
}
};
class NonCopyable
{
protected:
NonCopyable () {}
~NonCopyable () {} /// Protected non-virtual destructor
private:
NonCopyable (const NonCopyable &);
NonCopyable & operator = (const NonCopyable &);
};
class Arena {
public:
inline Arena();
inline explicit Arena( size_t reservedSize );
//~Arena();
Arena(const Arena&);
Arena(Arena && r) noexcept(true);
Arena& operator=(const Arena&);
Arena& operator=(Arena&&) noexcept(true);
inline void dependsOn( const Arena& p );
inline size_t getSize() const;
inline bool hasFree( size_t size, const void *address );
friend void* operator new ( size_t size, Arena& p );
friend void* operator new[] ( size_t size, Arena& p );
//private:
Reference<struct ArenaBlock> impl;
};
struct ArenaBlockRef {
ArenaBlock* next;
uint32_t nextBlockOffset;
};
struct ArenaBlock : NonCopyable, ThreadSafeReferenceCounted<ArenaBlock>
{
enum {
SMALL = 64,
LARGE = 4097 // If size == used == LARGE, then use hugeSize, hugeUsed
};
enum { NOT_TINY = 255, TINY_HEADER = 6 };
// int32_t referenceCount; // 4 bytes (in ThreadSafeReferenceCounted)
uint8_t tinySize, tinyUsed; // If these == NOT_TINY, use bigSize, bigUsed instead
// if tinySize != NOT_TINY, following variables aren't used
uint32_t bigSize, bigUsed; // include block header
uint32_t nextBlockOffset;
void delref() {
if (delref_no_destroy())
destroy();
}
bool isTiny() const { return tinySize != NOT_TINY; }
int size() const { if (isTiny()) return tinySize; else return bigSize; }
int used() const { if (isTiny()) return tinyUsed; else return bigUsed; }
inline int unused() const { if (isTiny()) return tinySize-tinyUsed; else return bigSize-bigUsed; }
const void* getData() const { return this; }
const void* getNextData() const { return (const uint8_t*)getData() + used(); }
size_t totalSize() {
if (isTiny()) return size();
size_t s = size();
int o = nextBlockOffset;
while (o) {
ArenaBlockRef* r = (ArenaBlockRef*)((char*)getData() + o);
s += r->next->totalSize();
o = r->nextBlockOffset;
}
return s;
}
// just for debugging:
void getUniqueBlocks(std::set<ArenaBlock*>& a) {
a.insert(this);
if (isTiny()) return;
int o = nextBlockOffset;
while (o) {
ArenaBlockRef* r = (ArenaBlockRef*)((char*)getData() + o);
r->next->getUniqueBlocks(a);
o = r->nextBlockOffset;
}
return;
}
inline int addUsed( int bytes ) {
if (isTiny()) {
int t = tinyUsed;
tinyUsed += bytes;
return t;
} else {
int t = bigUsed;
bigUsed += bytes;
return t;
}
}
void makeReference( ArenaBlock* next ) {
ArenaBlockRef* r = (ArenaBlockRef*)((char*)getData() + bigUsed);
r->next = next;
r->nextBlockOffset = nextBlockOffset;
nextBlockOffset = bigUsed;
bigUsed += sizeof(ArenaBlockRef);
}
static void dependOn( Reference<ArenaBlock>& self, ArenaBlock* other ) {
other->addref();
if (!self || self->isTiny() || self->unused() < sizeof(ArenaBlockRef))
create( SMALL, self )->makeReference(other);
else
self->makeReference( other );
}
static inline void* allocate( Reference<ArenaBlock>& self, int bytes ) {
ArenaBlock* b = self.getPtr();
if (!self || self->unused() < bytes)
b = create( bytes, self );
return (char*)b->getData() + b->addUsed(bytes);
}
// Return an appropriately-sized ArenaBlock to store the given data
static ArenaBlock* create( int dataSize, Reference<ArenaBlock>& next ) {
ArenaBlock* b;
if (dataSize <= SMALL-TINY_HEADER && !next) {
if (dataSize <= 16-TINY_HEADER) { b = (ArenaBlock*)FastAllocator<16>::allocate(); b->tinySize = 16; INSTRUMENT_ALLOCATE("Arena16"); }
else if (dataSize <= 32-TINY_HEADER) { b = (ArenaBlock*)FastAllocator<32>::allocate(); b->tinySize = 32; INSTRUMENT_ALLOCATE("Arena32"); }
else { b = (ArenaBlock*)FastAllocator<64>::allocate(); b->tinySize=64; INSTRUMENT_ALLOCATE("Arena64"); }
b->tinyUsed = TINY_HEADER;
} else {
int reqSize = dataSize + sizeof(ArenaBlock);
if (next) reqSize += sizeof(ArenaBlockRef);
if (reqSize < LARGE) {
// Each block should be larger than the previous block, up to a limit, to minimize allocations
// Worst-case allocation pattern: 1 +10 +17 +42 +67 +170 +323 +681 +1348 +2728 +2210 +2211 (+1K +3K+1 +4K)*
// Overhead: 4X for small arenas, 3X intermediate, 1.33X for large arenas
int prevSize = next ? next->size() : 0;
reqSize = std::max( reqSize, std::min( prevSize*2, std::max( LARGE-1, reqSize*4 ) ) );
}
if (reqSize < LARGE) {
if (reqSize <= 128) { b = (ArenaBlock*)FastAllocator<128>::allocate(); b->bigSize = 128; INSTRUMENT_ALLOCATE("Arena128"); }
else if (reqSize <= 256) { b = (ArenaBlock*)FastAllocator<256>::allocate(); b->bigSize = 256; INSTRUMENT_ALLOCATE("Arena256"); }
else if (reqSize <= 512) { b = (ArenaBlock*)FastAllocator<512>::allocate(); b->bigSize = 512; INSTRUMENT_ALLOCATE("Arena512"); }
else if (reqSize <= 1024) { b = (ArenaBlock*)FastAllocator<1024>::allocate(); b->bigSize = 1024; INSTRUMENT_ALLOCATE("Arena1024"); }
else if (reqSize <= 2048) { b = (ArenaBlock*)FastAllocator<2048>::allocate(); b->bigSize = 2048; INSTRUMENT_ALLOCATE("Arena2048"); }
else { b = (ArenaBlock*)FastAllocator<4096>::allocate(); b->bigSize = 4096; INSTRUMENT_ALLOCATE("Arena4096"); }
b->tinySize = b->tinyUsed = NOT_TINY;
b->bigUsed = sizeof(ArenaBlock);
} else {
#ifdef ALLOC_INSTRUMENTATION
allocInstr[ "ArenaHugeKB" ].alloc( (reqSize+1023)>>10 );
#endif
b = (ArenaBlock*)new uint8_t[ reqSize ];
b->tinySize = b->tinyUsed = NOT_TINY;
b->bigSize = reqSize;
b->bigUsed = sizeof(ArenaBlock);
// If the new block has less free space than the old block, make the old block depend on it
if (next && !next->isTiny() && next->unused() >= reqSize-dataSize) {
b->nextBlockOffset = 0;
b->setrefCountUnsafe(1);
next->makeReference(b);
return b;
}
}
b->nextBlockOffset = 0;
if (next) b->makeReference(next.getPtr());
}
b->setrefCountUnsafe(1);
next.setPtrUnsafe(b);
return b;
}
inline void destroy();
void destroyLeaf() {
if (isTiny()) {
if (tinySize <= 16) { FastAllocator<16>::release(this); INSTRUMENT_RELEASE("Arena16");}
else if (tinySize <= 32) { FastAllocator<32>::release(this); INSTRUMENT_RELEASE("Arena32"); }
else { FastAllocator<64>::release(this); INSTRUMENT_RELEASE("Arena64"); }
} else {
if (bigSize <= 128) { FastAllocator<128>::release(this); INSTRUMENT_RELEASE("Arena128"); }
else if (bigSize <= 256) { FastAllocator<256>::release(this); INSTRUMENT_RELEASE("Arena256"); }
else if (bigSize <= 512) { FastAllocator<512>::release(this); INSTRUMENT_RELEASE("Arena512"); }
else if (bigSize <= 1024) { FastAllocator<1024>::release(this); INSTRUMENT_RELEASE("Arena1024"); }
else if (bigSize <= 2048) { FastAllocator<2048>::release(this); INSTRUMENT_RELEASE("Arena2048"); }
else if (bigSize <= 4096) { FastAllocator<4096>::release(this); INSTRUMENT_RELEASE("Arena4096"); }
else {
#ifdef ALLOC_INSTRUMENTATION
allocInstr[ "ArenaHugeKB" ].dealloc( (bigSize+1023)>>10 );
#endif
delete[] (uint8_t*)this;
}
}
}
private:
static void* operator new(size_t s); // not implemented
};
inline Arena::Arena() : impl( NULL ) {}
inline Arena::Arena(size_t reservedSize) : impl( 0 ) {
UNSTOPPABLE_ASSERT( reservedSize < std::numeric_limits<int>::max() );
if (reservedSize)
ArenaBlock::create((int)reservedSize,impl);
}
inline Arena::Arena( const Arena& r ) : impl( r.impl ) {}
inline Arena::Arena(Arena && r) noexcept(true) : impl(std::move(r.impl)) {}
inline Arena& Arena::operator=(const Arena& r) {
impl = r.impl;
return *this;
}
inline Arena& Arena::operator=(Arena&& r) noexcept(true) {
impl = std::move(r.impl);
return *this;
}
inline void Arena::dependsOn( const Arena& p ) {
if (p.impl)
ArenaBlock::dependOn( impl, p.impl.getPtr() );
}
inline size_t Arena::getSize() const { return impl ? impl->totalSize() : 0; }
inline bool Arena::hasFree( size_t size, const void *address ) { return impl && impl->unused() >= size && impl->getNextData() == address; }
inline void* operator new ( size_t size, Arena& p ) {
UNSTOPPABLE_ASSERT( size < std::numeric_limits<int>::max() );
return ArenaBlock::allocate( p.impl, (int)size );
}
inline void operator delete( void*, Arena& p ) {}
inline void* operator new[] ( size_t size, Arena& p ) {
UNSTOPPABLE_ASSERT( size < std::numeric_limits<int>::max() );
return ArenaBlock::allocate( p.impl, (int)size );
}
inline void operator delete[]( void*, Arena& p ) {}
template <class Archive>
inline void load( Archive& ar, Arena& p ) {
p = ar.arena();
}
template <class Archive>
inline void save( Archive& ar, const Arena& p ) {
// No action required
}
//#define STANDALONE_ALWAYS_COPY
template <class T>
class Standalone : private Arena, public T {
public:
// T must have no destructor
Arena& arena() { return *(Arena*)this; }
const Arena& arena() const { return *(const Arena*)this; }
T& contents() { return *(T*)this; }
T const& contents() const { return *(T const*)this; }
Standalone() {}
Standalone( const T& t ) : Arena( t.expectedSize() ), T( arena(), t ) {}
Standalone<T>& operator=( const T& t ) {
Arena old = std::move( arena() ); // We want to defer the destruction of the arena until after we have copied t, in case it cross-references our previous value
*(Arena*)this = Arena(t.expectedSize());
*(T*)this = T( arena(), t );
return *this;
}
// Always-copy mode was meant to make alloc instrumentation more useful by making allocations occur at the final resting place of objects leaked
// It doesn't actually work because some uses of Standalone things assume the object's memory will not change on copy or assignment
#ifdef STANDALONE_ALWAYS_COPY
// Treat Standalone<T>'s as T's in construction and assignment so the memory is copied
Standalone( const T& t, const Arena& arena ) : Standalone(t) {}
Standalone( const Standalone<T> & t ) : Standalone((T const&)t) {}
Standalone( const Standalone<T> && t ) : Standalone((T const&)t) {}
Standalone<T>& operator=( const Standalone<T> &&t ) {
*this = (T const&)t;
return *this;
}
Standalone<T>& operator=( const Standalone<T> &t ) {
*this = (T const&)t;
return *this;
}
#else
Standalone( const T& t, const Arena& arena ) : Arena( arena ), T( t ) {}
Standalone( const Standalone<T> & t ) : Arena((Arena const&)t), T((T const&)t) {}
Standalone<T>& operator=( const Standalone<T> & t ) {
*(Arena*)this = (Arena const&)t;
*(T*)this = (T const&)t;
return *this;
}
#endif
template <class Archive>
void serialize(Archive& ar) {
// FIXME: something like BinaryReader(ar) >> arena >> *(T*)this; to guarantee standalone arena???
//T tmp;
//ar >> tmp;
//*this = tmp;
ar & (*(T*)this) & arena();
}
/*static Standalone<T> fakeStandalone( const T& t ) {
Standalone<T> x;
*(T*)&x = t;
return x;
}*/
private:
template <class U> Standalone( Standalone<U> const& ); // unimplemented
template <class U> Standalone<T> const& operator=( Standalone<U> const& ); // unimplemented
};
extern std::string format(const char* form, ...);
#pragma pack( push, 4 )
class StringRef {
public:
StringRef() : data(0), length(0) {}
StringRef( Arena& p, const StringRef& toCopy ) : data( new (p) uint8_t[toCopy.size()] ), length( toCopy.size() ) {
memcpy( (void*)data, toCopy.data, length );
}
StringRef( Arena& p, const std::string& toCopy ) : length( (int)toCopy.size() ) {
UNSTOPPABLE_ASSERT( toCopy.size() <= std::numeric_limits<int>::max());
data = new (p) uint8_t[toCopy.size()];
if (length) memcpy( (void*)data, &toCopy[0], length );
}
StringRef( Arena& p, const uint8_t* toCopy, int length ) : data( new (p) uint8_t[length] ), length(length) {
memcpy( (void*)data, toCopy, length );
}
StringRef( const uint8_t* data, int length ) : data(data), length(length) {}
StringRef( const std::string& s ) : data((const uint8_t*)s.c_str()), length((int)s.size()) {
if (s.size() > std::numeric_limits<int>::max()) abort();
}
//StringRef( const StringRef& p );
const uint8_t* begin() const { return data; }
const uint8_t* end() const { return data + length; }
int size() const { return length; }
uint8_t operator[](int i) const { return data[i]; }
StringRef substr(int start) const { return StringRef( data + start, length - start ); }
StringRef substr(int start, int size) const { return StringRef( data + start, size ); }
bool startsWith( const StringRef& s ) const { return size() >= s.size() && !memcmp(begin(), s.begin(), s.size()); }
bool endsWith( const StringRef& s ) const { return size() >= s.size() && !memcmp(end()-s.size(), s.begin(), s.size()); }
StringRef withPrefix( const StringRef& prefix, Arena& arena ) const {
uint8_t* s = new (arena) uint8_t[ prefix.size() + size() ];
memcpy(s, prefix.begin(), prefix.size());
memcpy(s+prefix.size(), begin(), size());
return StringRef(s,prefix.size() + size());
}
Standalone<StringRef> withPrefix( const StringRef& prefix ) const {
Standalone<StringRef> r;
((StringRef &)r) = withPrefix(prefix, r.arena());
return r;
}
StringRef removePrefix( const StringRef& s ) const {
// pre: startsWith(s)
UNSTOPPABLE_ASSERT( s.size() <= size() ); //< In debug mode, we could check startsWith()
return substr( s.size() );
}
std::string toString() const { return std::string( (const char*)data, length ); }
std::string printable() const {
std::string s;
for (int i = 0; i<length; i++) {
uint8_t b = (*this)[i];
if (b >= 32 && b < 127 && b != '\\') s += (char)b;
else if (b == '\\') s += "\\\\";
else s += format("\\x%02x", b);
}
return s;
}
int expectedSize() const { return size(); }
int compare( StringRef const& other ) const {
int c = memcmp( begin(), other.begin(), std::min( size(), other.size() ) );
if (c!=0) return c;
return size() - other.size();
}
private:
// Unimplemented; blocks conversion through std::string
StringRef( char* );
const uint8_t* data;
int length;
};
#pragma pack( pop )
#define LiteralStringRef( str ) StringRef( (const uint8_t*)(str), sizeof((str))-1 )
// makeString is used to allocate a Standalone<StringRef> of a known length for later
// mutation (via mutateString). If you need to append to a string of unknown length,
// consider factoring StringBuffer from DiskQueue.actor.cpp.
inline static Standalone<StringRef> makeString( int length ) {
Standalone<StringRef> returnString;
uint8_t *outData = new (returnString.arena()) uint8_t[length];
((StringRef&)returnString) = StringRef(outData, length);
return returnString;
}
inline static StringRef makeString( int length, Arena& arena ) {
uint8_t *outData = new (arena) uint8_t[length];
return StringRef(outData, length);
}
// mutateString() simply casts away const and returns a pointer that can be used to mutate the
// contents of the given StringRef (it will also accept Standalone<StringRef>). Obviously this
// is only legitimate if you know where the StringRef's memory came from and that it is not shared!
inline static uint8_t* mutateString( StringRef& s ) { return const_cast<uint8_t*>(s.begin()); }
template <class Archive>
inline void load( Archive& ar, StringRef& value ) {
uint32_t length;
ar >> length;
value = StringRef(ar.arenaRead(length), length);
}
template <class Archive>
inline void save( Archive& ar, const StringRef& value ) {
ar << (uint32_t)value.size();
ar.serializeBytes( value.begin(), value.size() );
}
inline bool operator == (const StringRef& lhs, const StringRef& rhs ) {
return lhs.size() == rhs.size() && !memcmp(lhs.begin(), rhs.begin(), lhs.size());
}
inline bool operator < ( const StringRef& lhs, const StringRef& rhs ) {
int c = memcmp( lhs.begin(), rhs.begin(), std::min(lhs.size(), rhs.size()) );
if (c!=0) return c<0;
return lhs.size() < rhs.size();
}
inline bool operator > ( const StringRef& lhs, const StringRef& rhs ) {
int c = memcmp( lhs.begin(), rhs.begin(), std::min(lhs.size(), rhs.size()) );
if (c!=0) return c>0;
return lhs.size() > rhs.size();
}
inline bool operator != (const StringRef& lhs, const StringRef& rhs ) { return !(lhs==rhs); }
inline bool operator <= ( const StringRef& lhs, const StringRef& rhs ) { return !(lhs>rhs); }
inline bool operator >= ( const StringRef& lhs, const StringRef& rhs ) { return !(lhs<rhs); }
// This trait is used by VectorRef to determine if it should just memcpy the vector contents.
// FIXME: VectorRef really should use std::is_trivially_copyable for this BUT that is not implemented
// in gcc c++0x so instead we will use this custom trait which defaults to std::is_trivial, which
// handles most situations but others will have to be specialized.
template <typename T>
struct memcpy_able : std::is_trivial<T> {};
template <>
struct memcpy_able<UID> : std::integral_constant<bool, true> {};
template <class T>
class VectorRef {
public:
// T must be trivially destructible (and copyable)!
VectorRef() : data(0), m_size(0), m_capacity(0) {}
// Arena constructor for non-Ref types, identified by memcpy_able
template<class T2 = T>
VectorRef( Arena& p, const VectorRef<T>& toCopy, typename std::enable_if<memcpy_able<T2>::value, int>::type = 0)
: data( (T*)new (p) uint8_t[sizeof(T)*toCopy.size()] ),
m_size( toCopy.size() ), m_capacity( toCopy.size() )
{
memcpy(data, toCopy.data, m_size * sizeof(T));
}
// Arena constructor for Ref types, which must have an Arena constructor
template<class T2 = T>
VectorRef( Arena& p, const VectorRef<T>& toCopy, typename std::enable_if<!memcpy_able<T2>::value, int>::type = 0)
: data( (T*)new (p) uint8_t[sizeof(T)*toCopy.size()] ),
m_size( toCopy.size() ), m_capacity( toCopy.size() )
{
for(int i=0; i<m_size; i++)
new (&data[i]) T(p, toCopy[i]);
}
VectorRef( T* data, int size ) : data(data), m_size(size), m_capacity(size) {}
//VectorRef( const VectorRef<T>& toCopy ) : data( toCopy.data ), m_size( toCopy.m_size ), m_capacity( toCopy.m_capacity ) {}
//VectorRef<T>& operator=( const VectorRef<T>& );
const T* begin() const { return data; }
const T* end() const { return data + m_size; }
T const& front() const { return *begin(); }
T const& back() const { return end()[-1]; }
int size() const { return m_size; }
const T& operator[](int i) const { return data[i]; }
std::reverse_iterator<const T*> rbegin() const { return std::reverse_iterator<const T*>( end() ); }
std::reverse_iterator<const T*> rend() const { return std::reverse_iterator<const T*>( begin() ); }
VectorRef slice(int begin, int end) const { return VectorRef(data+begin, end-begin); }
bool operator == ( VectorRef<T> const& rhs ) const {
if (size() != rhs.size()) return false;
for(int i=0; i<m_size; i++)
if ( (*this)[i] != rhs[i] )
return false;
return true;
}
// Warning: Do not mutate a VectorRef that has previously been copy constructed or assigned,
// since copies will share data
T* begin() { return data; }
T* end() { return data + m_size; }
T& front() { return *begin(); }
T& back() { return end()[-1]; }
T& operator[](int i) { return data[i]; }
void push_back( Arena& p, const T& value ) {
if (m_size + 1 > m_capacity) reallocate(p, m_size+1);
new (&data[m_size]) T(value);
m_size++;
}
// invokes the "Deep copy constructor" T(Arena&, const T&) moving T entirely into arena
void push_back_deep( Arena& p, const T& value ) {
if (m_size + 1 > m_capacity) reallocate(p, m_size+1);
new (&data[m_size]) T(p, value);
m_size++;
}
void append( Arena& p, const T* begin, int count ) {
if (m_size + count > m_capacity) reallocate(p, m_size + count);
memcpy( data+m_size, begin, sizeof(T)*count );
m_size += count;
}
template <class It>
void append_deep( Arena& p, It begin, int count ) {
if (m_size + count > m_capacity) reallocate(p, m_size + count);
for(int i=0; i<count; i++)
new (&data[m_size+i]) T( p, *begin++ );
m_size += count;
}
void pop_back() { m_size--; }
void pop_front( int count ) {
count = std::min(m_size, count);
data += count;
m_size -= count;
m_capacity -= count;
}
void resize( Arena& p, int size ) {
if (size > m_capacity) reallocate(p, size);
for(int i=m_size; i<size; i++)
new (&data[i]) T();
m_size = size;
}
void reserve( Arena& p, int size ) {
if (size > m_capacity) reallocate(p, size);
}
// expectedSize() for non-Ref types, identified by memcpy_able
template<class T2 = T>
typename std::enable_if<memcpy_able<T2>::value, size_t>::type expectedSize() const {
return sizeof(T)*m_size;
}
// expectedSize() for Ref types, which must in turn have expectedSize() implemented.
template<class T2 = T>
typename std::enable_if<!memcpy_able<T2>::value, size_t>::type expectedSize() const
{
size_t t = sizeof(T)*m_size;
for(int i=0; i<m_size; i++)
t += data[i].expectedSize();
return t;
}
int capacity() const {
return m_capacity;
}
private:
T* data;
int m_size, m_capacity;
void reallocate(Arena& p, int requiredCapacity) {
requiredCapacity = std::max( m_capacity*2, requiredCapacity );
// SOMEDAY: Maybe we are right at the end of the arena and can expand cheaply
T* newData = (T*)new (p) uint8_t[ requiredCapacity * sizeof(T) ];
memcpy(newData, data, m_size*sizeof(T));
data = newData;
m_capacity = requiredCapacity;
}
};
template <class Archive, class T>
inline void load( Archive& ar, VectorRef<T>& value ) {
// FIXME: range checking for length, here and in other serialize code
uint32_t length;
ar >> length;
UNSTOPPABLE_ASSERT( length*sizeof(T) < (100<<20) );
// SOMEDAY: Can we avoid running constructors for all the values?
value.resize(ar.arena(), length);
for(uint32_t i=0; i<length; i++)
ar >> value[i];
}
template <class Archive, class T>
inline void save( Archive& ar, const VectorRef<T>& value ) {
uint32_t length = value.size();
ar << length;
for(uint32_t i=0; i<length; i++)
ar << value[i];
}
void ArenaBlock::destroy() {
// If the stack never contains more than one item, nothing will be allocated from stackArena.
// If stackArena is used, it will always be a linked list, so destroying *it* will not create another arena
ArenaBlock* tinyStack = this;
Arena stackArena;
VectorRef<ArenaBlock*> stack( &tinyStack, 1 );
while (stack.size()) {
ArenaBlock* b = stack.end()[-1];
stack.pop_back();
if (!b->isTiny()) {
int o = b->nextBlockOffset;
while (o) {
ArenaBlockRef* br = (ArenaBlockRef*)((char*)b->getData() + o);
if (br->next->delref_no_destroy())
stack.push_back( stackArena, br->next );
o = br->nextBlockOffset;
}
}
b->destroyLeaf();
}
}
#endif
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