| /**@file Simplified Vector template with aliases. */ |
| /* |
| * Copyright 2008 Free Software Foundation, Inc. |
| * Copyright 2014 Range Networks, Inc. |
| * |
| * This software is distributed under the terms of the GNU Affero Public License. |
| * See the COPYING file in the main directory for details. |
| * |
| * This use of this software may be subject to additional restrictions. |
| * See the LEGAL file in the main directory for details. |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU Affero General Public License as published by |
| the Free Software Foundation, either version 3 of the License, or |
| (at your option) any later version. |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU Affero General Public License for more details. |
| You should have received a copy of the GNU Affero General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| |
| |
| |
| #ifndef VECTOR_H |
| #define VECTOR_H |
| |
| #include <string.h> |
| #include <iostream> |
| #include <assert.h> |
| #include <stdio.h> |
| // We cant use Logger.h in this file... |
| extern int gVectorDebug; |
| //#define ENABLE_VECTORDEBUG |
| #ifdef ENABLE_VECTORDEBUG |
| #define VECTORDEBUG(...) { printf(__VA_ARGS__); printf(" this=%p [%p,%p,%p]\n",(void*)this,(void*)&mData,mStart,mEnd); } |
| //#define VECTORDEBUG(msg) { std::cout<<msg<<std::endl; } |
| #else |
| #define VECTORDEBUG(...) |
| #endif |
| |
| #define BITVECTOR_REFCNTS 0 |
| |
| #if BITVECTOR_REFCNTS |
| // (pat) Started to add refcnts, decided against it for now. |
| template <class T> class RCData : public RefCntBase { |
| public: |
| T* mPointer; |
| }; |
| #endif |
| |
| |
| /** |
| A simplified Vector template with aliases. |
| Unlike std::vector, this class does not support dynamic resizing. |
| Unlike std::vector, this class does support "aliases" and subvectors. |
| */ |
| // (pat) Nov 2013: Vector and the derived classes BitVector and SoftVector were originally written with behavior |
| // that differed for const and non-const cases, making them very difficult to use and resulting in many extremely |
| // difficult to find bugs in the code base. |
| // Ultimately these classes should all be converted to reference counted methodologies, but as an interim measure |
| // I am rationalizing their behavior until we flush out all places in the code base that inadvertently depended |
| // on the original behavior. This is done with assert statements in BitVector methods. |
| // ==== |
| // What the behavior was probably supposed to be: |
| // Vectors can 'own' the data they point to or not. Only one Vector 'owns' the memory at a time, |
| // so that automatic destruction can be used. So whenever there is an operation that yields one |
| // vector from another the options were: clone (allocate a new vector from memory), alias (make the |
| // new vector point into the memory of the original vector) or shift (the new Vector steals the |
| // memory ownership from the original vector.) |
| // The const copy-constructor did a clone, the non-const copy constructor did a shiftMem, and the segment and |
| // related methods (head, tail, etc) returned aliases. |
| // Since a copy-constructor is inserted transparently in sometimes surprising places, this made the |
| // class very difficult to use. Moreover, since the C++ standard specifies that a copy-constructor is used |
| // to copy the return value from functions, it makes it literally impossible for a function to fully control |
| // the return value. Our code has relied on the "Return Value Optimization" which says that the C++ compiler |
| // may omit the copy-construction of the return value even if the copy-constructor has side-effects, which ours does. |
| // This methodology is fundamentally incompatible with C++. |
| // What the original behavior actually was: |
| // class Vector: |
| // The copy-constructor and assignment operators did a clone for the const case and a shift for the non-const case. |
| // This is really horrible. |
| // The segment methods were identical for const and non-const cases, always returning an alias. |
| // This also resulted in zillions of redundant mallocs and copies throughout the code base. |
| // class BitVector: |
| // Copy-constructor: |
| // BitVector did not have any copy-constructors, and I think the intent was that it would have the same behavior |
| // as Vector, but that is not how C++ works: with no copy-constructor the default copy-constructor |
| // uses only the const case, so only the const Vector copy-constructor was used. Therefore it always cloned, |
| // and the code base relied heavily on the "Return Value Optimization" to work at all. |
| // Assignment operator: |
| // BitVector did not have one, so C++ makes a default one that calls Vector::operator=() as a side effect, |
| // which did a clone; not sure if there was a non-const version and no longer care. |
| // segment methods: |
| // The non-const segment() returned an alias, and the const segment() returned a clone. |
| // I think the intent was that the behavior should be the same as Vector, but there was a conversion |
| // of the result of the const segment() method from Vector to BitVector which caused the Vector copy-constructor |
| // to be (inadvertently) invoked, resulting in the const version of the segment method returning a clone. |
| // What the behavior is now: |
| // VectorBase: |
| // There is a new VectorBase class that has only the common methods and extremely basic constructors. |
| // The VectorBase class MUST NOT CONTAIN: copy constructors, non-trivial constructors called from derived classes, |
| // or any method that returns a VectorBase type object. Why? Because any of the above when used in derived classes |
| // can cause copy-constructor invocation, often surprisingly, obfuscating the code. |
| // Each derived class must provide its own: copy-constructors and segment() and related methods, since we do not |
| // want to inadvertently invoke a copy-constructor to convert the segment() result from VectorBase to the derived type. |
| // BitVector: |
| // The BitVector copy-constructor and assignment operator (inherited from VectorBase) paradigm is: |
| // if the copied Vector owned memory, perform a clone so the new vector owns memory also, |
| // otherwise just do a simple copy, which is another alias. This isnt perfect but works every place |
| // in our code base and easier to use than the previous paradigm. |
| // The segment method always returns an alias. |
| // If you want a clone of a segment, use cloneSegment(), which replaces the previous: const segment(...) const method. |
| // Note that the semantics of cloneSegment still rely on the Return Value Optimization. Oh well, we should use refcnts. |
| // Vector: |
| // I left Vector alone (except for rearrangement to separate out VectorBase.) Vector should just not be used. |
| // SoftVector: |
| // SoftVector and signalVector should be updated similar to BitVector, but I did not want to disturb them. |
| // What the behavior should be: |
| // All these should be reference-counted, similar to ByteVector. |
| template <class T> class VectorBase |
| { |
| // TODO -- Replace memcpy calls with for-loops. (pat) in case class T is not POD [Plain Old Data] |
| |
| protected: |
| #if BITVECTOR_REFCNTS |
| typedef RefCntPointer<RCData<T> > VectorDataType; |
| #else |
| typedef T* VectorDataType; |
| #endif |
| VectorDataType mData; ///< allocated data block. |
| T* mStart; ///< start of useful data |
| T* mEnd; ///< end of useful data + 1 |
| |
| // Init vector with specified size. Previous contents are completely discarded. This is only used for initialization. |
| void vInit(size_t elements) |
| { |
| mData = elements ? new T[elements] : NULL; |
| mStart = mData; // This is where mStart get set to zero |
| mEnd = mStart + elements; |
| } |
| |
| /** Assign from another Vector, shifting ownership. */ |
| // (pat) This should be eliminated, but it is used by Vector and descendents. |
| void shiftMem(VectorBase<T>&other) |
| { |
| VECTORDEBUG("VectorBase::shiftMem(%p)",(void*)&other); |
| this->clear(); |
| this->mData=other.mData; |
| this->mStart=other.mStart; |
| this->mEnd=other.mEnd; |
| other.mData=NULL; |
| } |
| |
| // Assign from another Vector, making this an alias to other. |
| void makeAlias(const VectorBase<T> &other) |
| { |
| if (this->getData()) { |
| assert(this->getData() != other.getData()); // Not possible by the semantics of Vector. |
| this->clear(); |
| } |
| this->mStart=const_cast<T*>(other.mStart); |
| this->mEnd=const_cast<T*>(other.mEnd); |
| } |
| |
| public: |
| |
| /** Return the size of the Vector in units, ie, the number of T elements. */ |
| size_t size() const |
| { |
| assert(mStart>=mData); |
| assert(mEnd>=mStart); |
| return mEnd - mStart; |
| } |
| |
| /** Return size in bytes. */ |
| size_t bytes() const { return this->size()*sizeof(T); } |
| |
| /** Change the size of the Vector in items (not bytes), discarding content. */ |
| void resize(size_t newElements) { |
| //VECTORDEBUG("VectorBase::resize("<<(void*)this<<","<<newElements<<")"); |
| VECTORDEBUG("VectorBase::resize(%p,%d) %s",this,newElements, (mData?"delete":"")); |
| if (mData!=NULL) delete[] mData; |
| vInit(newElements); |
| } |
| |
| /** Release memory and clear pointers. */ |
| void clear() { this->resize(0); } |
| |
| |
| /** Copy data from another vector. */ |
| void clone(const VectorBase<T>& other) { |
| this->resize(other.size()); |
| memcpy(mData,other.mStart,other.bytes()); |
| } |
| |
| void vConcat(const VectorBase<T>&other1, const VectorBase<T>&other2) { |
| this->resize(other1.size()+other2.size()); |
| memcpy(this->mStart, other1.mStart, other1.bytes()); |
| memcpy(this->mStart+other1.size(), other2.mStart, other2.bytes()); |
| } |
| |
| protected: |
| |
| VectorBase() : mData(0), mStart(0), mEnd(0) {} |
| |
| /** Build a Vector with explicit values. */ |
| VectorBase(VectorDataType wData, T* wStart, T* wEnd) :mData(wData),mStart(wStart),mEnd(wEnd) { |
| //VECTORDEBUG("VectorBase("<<(void*)wData); |
| VECTORDEBUG("VectorBase(%p,%p,%p)",this->getData(),wStart,wEnd); |
| } |
| |
| public: |
| |
| /** Destroy a Vector, deleting held memory. */ |
| ~VectorBase() { |
| //VECTORDEBUG("~VectorBase("<<(void*)this<<")"); |
| VECTORDEBUG("~VectorBase(%p)",this); |
| this->clear(); |
| } |
| |
| bool isOwner() { return !!this->mData; } // Do we own any memory ourselves? |
| |
| std::string inspect() const { |
| char buf[100]; |
| snprintf(buf,100," mData=%p mStart=%p mEnd=%p ",(void*)mData,mStart,mEnd); |
| return std::string(buf); |
| } |
| |
| |
| /** |
| Copy part of this Vector to a segment of another Vector. |
| @param other The other vector. |
| @param start The start point in the other vector. |
| @param span The number of elements to copy. |
| */ |
| void copyToSegment(VectorBase<T>& other, size_t start, size_t span) const |
| { |
| T* base = other.mStart + start; |
| assert(base+span<=other.mEnd); |
| assert(mStart+span<=mEnd); |
| memcpy(base,mStart,span*sizeof(T)); |
| } |
| |
| /** Copy all of this Vector to a segment of another Vector. */ |
| void copyToSegment(VectorBase<T>& other, size_t start=0) const { copyToSegment(other,start,size()); } |
| |
| void copyTo(VectorBase<T>& other) const { copyToSegment(other,0,size()); } |
| |
| /** |
| Copy a segment of this vector into another. |
| @param other The other vector (to copt into starting at 0.) |
| @param start The start point in this vector. |
| @param span The number of elements to copy. |
| WARNING: This function does NOT resize the result - you must set the result size before entering. |
| */ |
| void segmentCopyTo(VectorBase<T>& other, size_t start, size_t span) const |
| { |
| const T* base = mStart + start; |
| assert(base+span<=mEnd); |
| assert(other.mStart+span<=other.mEnd); |
| memcpy(other.mStart,base,span*sizeof(T)); |
| } |
| |
| void fill(const T& val) |
| { |
| T* dp=mStart; |
| while (dp<mEnd) *dp++=val; |
| } |
| |
| void fill(const T& val, unsigned start, unsigned length) |
| { |
| T* dp=mStart+start; |
| T* end=dp+length; |
| assert(end<=mEnd); |
| while (dp<end) *dp++=val; |
| } |
| |
| /** Assign from another Vector. */ |
| // (pat) This is used for both const and non-const cases. |
| // If the original vector owned memory, clone it, otherwise just copy the segment data. |
| void operator=(const VectorBase<T>& other) { |
| //std::cout << "Vector=(this="<<this->inspect()<<",other="<<other.inspect()<<")"<<endl; |
| if (other.getData()) { |
| this->clone(other); |
| } else { |
| this->makeAlias(other); |
| } |
| //std::cout << "Vector= after(this="<<this->inspect()<<")"<<endl; |
| } |
| |
| |
| T& operator[](size_t index) |
| { |
| assert(mStart+index<mEnd); |
| return mStart[index]; |
| } |
| |
| const T& operator[](size_t index) const |
| { |
| assert(mStart+index<mEnd); |
| return mStart[index]; |
| } |
| |
| const T* begin() const { return this->mStart; } |
| T* begin() { return this->mStart; } |
| const T* end() const { return this->mEnd; } |
| T* end() { return this->mEnd; } |
| #if BITVECTOR_REFCNTS |
| const T*getData() const { return this->mData.isNULL() ? 0 : this->mData->mPointer; } |
| #else |
| const T*getData() const { return this->mData; } |
| #endif |
| }; |
| |
| // (pat) Nov 2013. This class retains the original poor behavior. See comments at VectorBase |
| template <class T> class Vector : public VectorBase<T> |
| { |
| public: |
| |
| /** Build an empty Vector of a given size. */ |
| Vector(size_t wSize=0) { this->resize(wSize); } |
| |
| /** Build a Vector by shifting the data block. */ |
| Vector(Vector<T>& other) : VectorBase<T>(other.mData,other.mStart,other.mEnd) { other.mData=NULL; } |
| |
| /** Build a Vector by copying another. */ |
| Vector(const Vector<T>& other):VectorBase<T>() { this->clone(other); } |
| |
| /** Build a Vector with explicit values. */ |
| Vector(T* wData, T* wStart, T* wEnd) : VectorBase<T>(wData,wStart,wEnd) { } |
| |
| /** Build a vector from an existing block, NOT to be deleted upon destruction. */ |
| Vector(T* wStart, size_t span) : VectorBase<T>(NULL,wStart,wStart+span) { } |
| |
| /** Build a Vector by concatenation. */ |
| Vector(const Vector<T>& other1, const Vector<T>& other2):VectorBase<T>() { |
| assert(this->mData == 0); |
| this->vConcat(other1,other2); |
| } |
| |
| //@{ |
| |
| /** Assign from another Vector, shifting ownership. */ |
| void operator=(Vector<T>& other) { this->shiftMem(other); } |
| |
| /** Assign from another Vector, copying. */ |
| void operator=(const Vector<T>& other) { this->clone(other); } |
| |
| /** Return an alias to a segment of this Vector. */ |
| Vector<T> segment(size_t start, size_t span) |
| { |
| T* wStart = this->mStart + start; |
| T* wEnd = wStart + span; |
| assert(wEnd<=this->mEnd); |
| return Vector<T>(NULL,wStart,wEnd); |
| } |
| |
| /** Return an alias to a segment of this Vector. */ |
| const Vector<T> segment(size_t start, size_t span) const |
| { |
| T* wStart = this->mStart + start; |
| T* wEnd = wStart + span; |
| assert(wEnd<=this->mEnd); |
| return Vector<T>(NULL,wStart,wEnd); |
| } |
| |
| Vector<T> head(size_t span) { return segment(0,span); } |
| const Vector<T> head(size_t span) const { return segment(0,span); } |
| Vector<T> tail(size_t start) { return segment(start,this->size()-start); } |
| const Vector<T> tail(size_t start) const { return segment(start,this->size()-start); } |
| |
| /**@name Iterator types. */ |
| //@{ |
| typedef T* iterator; |
| typedef const T* const_iterator; |
| //@} |
| |
| //@} |
| }; |
| |
| |
| |
| |
| |
| /** Basic print operator for Vector objects. */ |
| template <class T> |
| std::ostream& operator<<(std::ostream& os, const Vector<T>& v) |
| { |
| for (unsigned i=0; i<v.size(); i++) os << v[i] << " "; |
| return os; |
| } |
| |
| |
| |
| #endif |
| // vim: ts=4 sw=4 |