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(svn r10388) -Cleanup: coding style (CBlobT & CBlobBaseSimple), removed CStrA

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pull/155/head
KUDr 18 years ago
parent 0e2982ddba
commit f9e47692cb
1 changed files with 293 additions and 113 deletions
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406
src/misc/blob.hpp
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@ -15,104 +15,196 @@ FORCEINLINE void MemCpyT(Titem_* d, const Titem_* s, int num_items = 1)
memcpy(d, s, num_items * sizeof(Titem_));
}
/** Base class for simple binary blobs.
* Item is byte.
* The word 'simple' means:
* - no configurable allocator type (always made from heap)
* - no smart deallocation - deallocation must be called from the same
* module (DLL) where the blob was allocated
* - no configurable allocation policy (how big blocks should be allocated)
* - no extra ownership policy (i.e. 'copy on write') when blob is copied
* - no thread synchronization at all
*
* Internal member layout:
* 1. The only class member is pointer to the first item (see union ptr_u).
* 2. Allocated block contains the blob header (see CHdr) followed by the raw byte data.
* Always, when it allocates memory the allocated size is:
* sizeof(CHdr) + <data capacity>
* 3. Two 'virtual' members (m_size and m_max_size) are stored in the CHdr at beginning
* of the alloated block.
* 4. The pointer (in ptr_u) points behind the header (to the first data byte).
* When memory block is allocated, the sizeof(CHdr) it added to it.
* 5. Benefits of this layout:
* - items are accessed in the simplest possible way - just dereferencing the pointer,
* which is good for performance (assuming that data are accessed most often).
* - sizeof(blob) is the same as the size of any other pointer
* 6. Drawbacks of this layout:
* - the fact, that pointer to the alocated block is adjusted by sizeof(CHdr) before
* it is stored can lead to several confusions:
* - it is not common pattern so the implementation code is bit harder to read
* - valgrind can generate warning that allocated block is lost (not accessible)
* */
* Item is byte.
* The word 'simple' means:
* - no configurable allocator type (always made from heap)
* - no smart deallocation - deallocation must be called from the same
* module (DLL) where the blob was allocated
* - no configurable allocation policy (how big blocks should be allocated)
* - no extra ownership policy (i.e. 'copy on write') when blob is copied
* - no thread synchronization at all
*
* Internal member layout:
* 1. The only class member is pointer to the first item (see union ptr_u).
* 2. Allocated block contains the blob header (see CHdr) followed by the raw byte data.
* Always, when it allocates memory the allocated size is:
* sizeof(CHdr) + <data capacity>
* 3. Two 'virtual' members (m_size and m_max_size) are stored in the CHdr at beginning
* of the alloated block.
* 4. The pointter (in ptr_u) pobsize_ts behind the header (to the first data byte).
* When memory block is allocated, the sizeof(CHdr) it added to it.
* 5. Benefits of this layout:
* - items are accessed in the simplest possible way - just dereferencing the pointer,
* which is good for performance (assuming that data are accessed most often).
* - sizeof(blob) is the same as the size of any other pointer
* 6. Drawbacks of this layout:
* - the fact, that pointer to the alocated block is adjusted by sizeof(CHdr) before
* it is stored can lead to several confusions:
* - it is not common pattern so the implementation code is bit harder to read
* - valgrind can generate warning that allocated block is lost (not accessible)
* */
class CBlobBaseSimple {
public:
typedef ::ptrdiff_t bsize_t;
typedef ::byte bitem_t;
protected:
/** header of the allocated memory block */
struct CHdr {
int m_size; ///< actual blob size in bytes
int m_max_size; ///< maximum (allocated) size in bytes
bsize_t m_size; ///< actual blob size in bytes
bsize_t m_max_size; ///< maximum (allocated) size in bytes
};
/** type used as class member */
union {
int8 *m_pData; ///< pointer to the first byte of data
CHdr *m_pHdr_1; ///< pointer just after the CHdr holding m_size and m_max_size
bitem_t *m_pData; ///< ptr to the first byte of data
wchar_t *m_pwData; ///< ptr to the first byte of data
CHdr *m_pHdr_1; ///< ptr just after the CHdr holding m_size and m_max_size
} ptr_u;
public:
static const int Ttail_reserve = 4; ///< four extra bytes will be always allocated and zeroed at the end
static const bsize_t Ttail_reserve = 4; ///< four extra bytes will be always allocated and zeroed at the end
/** default constructor - initializes empty blob */
FORCEINLINE CBlobBaseSimple() { InitEmpty(); }
/** constructor - create blob with data */
FORCEINLINE CBlobBaseSimple(const bitem_t *p, bsize_t num_bytes)
{
InitEmpty();
AppendRaw(p, num_bytes);
}
/** copy constructor */
FORCEINLINE CBlobBaseSimple(const CBlobBaseSimple& src)
{
InitEmpty();
AppendRaw(src);
}
/** move constructor - take ownership of blob data */
FORCEINLINE CBlobBaseSimple(CHdr * const & pHdr_1)
{
assert(pHdr_1 != NULL);
ptr_u.m_pHdr_1 = pHdr_1;
*(CHdr**)&pHdr_1 = NULL;
}
/** destructor */
FORCEINLINE ~CBlobBaseSimple() { Free(); }
FORCEINLINE ~CBlobBaseSimple()
{
Free();
}
protected:
/** initialize the empty blob by setting the ptr_u.m_pHdr_1 pointer to the static CHdr with
* both m_size and m_max_size containing zero */
FORCEINLINE void InitEmpty() { static CHdr hdrEmpty[] = {{0, 0}, {0, 0}}; ptr_u.m_pHdr_1 = &hdrEmpty[1]; }
* both m_size and m_max_size containing zero */
FORCEINLINE void InitEmpty()
{
static CHdr hdrEmpty[] = {{0, 0}, {0, 0}};
ptr_u.m_pHdr_1 = &hdrEmpty[1];
}
/** initialize blob by attaching it to the given header followed by data */
FORCEINLINE void Init(CHdr* hdr) { ptr_u.m_pHdr_1 = &hdr[1]; }
FORCEINLINE void Init(CHdr* hdr)
{
ptr_u.m_pHdr_1 = &hdr[1];
}
/** blob header accessor - use it rather than using the pointer arithmetics directly - non-const version */
FORCEINLINE CHdr& Hdr() { return ptr_u.m_pHdr_1[-1]; }
FORCEINLINE CHdr& Hdr()
{
return ptr_u.m_pHdr_1[-1];
}
/** blob header accessor - use it rather than using the pointer arithmetics directly - const version */
FORCEINLINE const CHdr& Hdr() const { return ptr_u.m_pHdr_1[-1]; }
FORCEINLINE const CHdr& Hdr() const
{
return ptr_u.m_pHdr_1[-1];
}
/** return reference to the actual blob size - used when the size needs to be modified */
FORCEINLINE int& RawSizeRef() { return Hdr().m_size; };
FORCEINLINE bsize_t& RawSizeRef()
{
return Hdr().m_size;
};
public:
/** return true if blob doesn't contain valid data */
FORCEINLINE bool IsEmpty() const { return RawSize() == 0; }
FORCEINLINE bool IsEmpty() const
{
return RawSize() == 0;
}
/** return the number of valid data bytes in the blob */
FORCEINLINE int RawSize() const { return Hdr().m_size; };
FORCEINLINE bsize_t RawSize() const
{
return Hdr().m_size;
};
/** return the current blob capacity in bytes */
FORCEINLINE int MaxRawSize() const { return Hdr().m_max_size; };
FORCEINLINE bsize_t MaxRawSize() const
{
return Hdr().m_max_size;
};
/** return pointer to the first byte of data - non-const version */
FORCEINLINE int8* RawData() { return ptr_u.m_pData; }
FORCEINLINE bitem_t* RawData()
{
return ptr_u.m_pData;
}
/** return pointer to the first byte of data - const version */
FORCEINLINE const int8* RawData() const { return ptr_u.m_pData; }
#if 0 // reenable when needed
FORCEINLINE const bitem_t* RawData() const
{
return ptr_u.m_pData;
}
/** return the 32 bit CRC of valid data in the blob */
FORCEINLINE uint32 Crc32() const {return CCrc32::Calc(RawData(), RawSize());}
#endif //0
//FORCEINLINE bsize_t Crc32() const
//{
// return CCrc32::Calc(RawData(), RawSize());
//}
/** invalidate blob's data - doesn't free buffer */
FORCEINLINE void Clear() { RawSizeRef() = 0; }
FORCEINLINE void Clear()
{
RawSizeRef() = 0;
}
/** free the blob's memory */
FORCEINLINE void Free() { if (MaxRawSize() > 0) {RawFree(&Hdr()); InitEmpty();} }
FORCEINLINE void Free()
{
if (MaxRawSize() > 0) {
RawFree(&Hdr());
InitEmpty();
}
}
/** copy data from another blob - replaces any existing blob's data */
FORCEINLINE void CopyFrom(const CBlobBaseSimple& src) { Clear(); AppendRaw(src); }
FORCEINLINE void CopyFrom(const CBlobBaseSimple& src)
{
Clear();
AppendRaw(src);
}
/** overtake ownership of data buffer from the source blob - source blob will become empty */
FORCEINLINE void MoveFrom(CBlobBaseSimple& src) { Free(); ptr_u.m_pData = src.ptr_u.m_pData; src.InitEmpty(); }
FORCEINLINE void MoveFrom(CBlobBaseSimple& src)
{
Free();
ptr_u.m_pData = src.ptr_u.m_pData;
src.InitEmpty();
}
/** swap buffers (with data) between two blobs (this and source blob) */
FORCEINLINE void Swap(CBlobBaseSimple& src) { int8 *tmp = ptr_u.m_pData; ptr_u.m_pData = src.ptr_u.m_pData; src.ptr_u.m_pData = tmp; }
FORCEINLINE void Swap(CBlobBaseSimple& src)
{
bitem_t *tmp = ptr_u.m_pData; ptr_u.m_pData = src.ptr_u.m_pData;
src.ptr_u.m_pData = tmp;
}
/** append new bytes at the end of existing data bytes - reallocates if necessary */
FORCEINLINE void AppendRaw(int8 *p, int num_bytes)
FORCEINLINE void AppendRaw(const void *p, bsize_t num_bytes)
{
assert(p != NULL);
if (num_bytes > 0) {
@ -130,27 +222,26 @@ public:
}
/** Reallocate if there is no free space for num_bytes bytes.
* @return pointer to the new data to be added */
FORCEINLINE int8* MakeRawFreeSpace(int num_bytes)
* @return pointer to the new data to be added */
FORCEINLINE bitem_t* MakeRawFreeSpace(bsize_t num_bytes)
{
assert(num_bytes >= 0);
int new_size = RawSize() + num_bytes;
bsize_t new_size = RawSize() + num_bytes;
if (new_size > MaxRawSize()) SmartAlloc(new_size);
FixTail();
return ptr_u.m_pData + RawSize();
}
/** Increase RawSize() by num_bytes.
* @return pointer to the new data added */
FORCEINLINE int8* GrowRawSize(int num_bytes)
* @return pointer to the new data added */
FORCEINLINE bitem_t* GrowRawSize(bsize_t num_bytes)
{
int8* pNewData = MakeRawFreeSpace(num_bytes);
bitem_t* pNewData = MakeRawFreeSpace(num_bytes);
RawSizeRef() += num_bytes;
return pNewData;
}
/** Decrease RawSize() by num_bytes. */
FORCEINLINE void ReduceRawSize(int num_bytes)
FORCEINLINE void ReduceRawSize(bsize_t num_bytes)
{
if (MaxRawSize() > 0 && num_bytes > 0) {
assert(num_bytes <= RawSize());
@ -158,15 +249,16 @@ public:
else RawSizeRef() = 0;
}
}
/** reallocate blob data if needed */
void SmartAlloc(int new_size)
void SmartAlloc(bsize_t new_size)
{
int old_max_size = MaxRawSize();
bsize_t old_max_size = MaxRawSize();
if (old_max_size >= new_size) return;
// calculate minimum block size we need to allocate
int min_alloc_size = sizeof(CHdr) + new_size + Ttail_reserve;
bsize_t min_alloc_size = sizeof(CHdr) + new_size + Ttail_reserve;
// ask allocation policy for some reasonable block size
int alloc_size = AllocPolicy(min_alloc_size);
bsize_t alloc_size = AllocPolicy(min_alloc_size);
// allocate new block
CHdr* pNewHdr = RawAlloc(alloc_size);
// setup header
@ -181,8 +273,9 @@ public:
if (old_max_size > 0)
RawFree(pOldHdr);
}
/** simple allocation policy - can be optimized later */
FORCEINLINE static int AllocPolicy(int min_alloc)
FORCEINLINE static bsize_t AllocPolicy(bsize_t min_alloc)
{
if (min_alloc < (1 << 9)) {
if (min_alloc < (1 << 5)) return (1 << 5);
@ -201,58 +294,133 @@ public:
}
/** all allocation should happen here */
static FORCEINLINE CHdr* RawAlloc(int num_bytes) { return (CHdr*)malloc(num_bytes); }
static FORCEINLINE CHdr* RawAlloc(bsize_t num_bytes)
{
return (CHdr*)malloc(num_bytes);
}
/** all deallocations should happen here */
static FORCEINLINE void RawFree(CHdr* p) { free(p); }
static FORCEINLINE void RawFree(CHdr* p)
{
free(p);
}
/** fixing the four bytes at the end of blob data - useful when blob is used to hold string */
FORCEINLINE void FixTail()
FORCEINLINE void FixTail() const
{
if (MaxRawSize() > 0) {
int8 *p = &ptr_u.m_pData[RawSize()];
for (int i = 0; i < Ttail_reserve; i++) p[i] = 0;
bitem_t *p = &ptr_u.m_pData[RawSize()];
for (bsize_t i = 0; i < Ttail_reserve; i++) {
p[i] = 0;
}
}
}
};
/** Blob - simple dynamic Titem_ array. Titem_ (template argument) is a placeholder for any type.
* Titem_ can be any integral type, pointer, or structure. Using Blob instead of just plain C array
* simplifies the resource management in several ways:
* 1. When adding new item(s) it automatically grows capacity if needed.
* 2. When variable of type Blob comes out of scope it automatically frees the data buffer.
* 3. Takes care about the actual data size (number of used items).
* 4. Dynamically constructs only used items (as opposite of static array which constructs all items) */
* Titem_ can be any integral type, pointer, or structure. Using Blob instead of just plain C array
* simplifies the resource management in several ways:
* 1. When adding new item(s) it automatically grows capacity if needed.
* 2. When variable of type Blob comes out of scope it automatically frees the data buffer.
* 3. Takes care about the actual data size (number of used items).
* 4. Dynamically constructs only used items (as opposite of static array which constructs all items) */
template <class Titem_, class Tbase_ = CBlobBaseSimple>
class CBlobT : public CBlobBaseSimple {
class CBlobT : public Tbase_ {
// make template arguments public:
public:
typedef Titem_ Titem;
typedef Tbase_ Tbase;
typedef typename Tbase::bsize_t bsize_t;
static const int Titem_size = sizeof(Titem);
static const bsize_t Titem_size = sizeof(Titem);
struct OnTransfer {
typename Tbase_::CHdr *m_pHdr_1;
OnTransfer(const OnTransfer& src) : m_pHdr_1(src.m_pHdr_1) {assert(src.m_pHdr_1 != NULL); *(typename Tbase_::CHdr**)&src.m_pHdr_1 = NULL;}
OnTransfer(CBlobT& src) : m_pHdr_1(src.ptr_u.m_pHdr_1) {src.InitEmpty();}
~OnTransfer() {assert(m_pHdr_1 == NULL);}
};
/** Default constructor - makes new Blob ready to accept any data */
FORCEINLINE CBlobT() : Tbase() {}
FORCEINLINE CBlobT()
: Tbase()
{}
/** Constructor - makes new Blob with data */
FORCEINLINE CBlobT(const Titem_ *p, bsize_t num_items)
: Tbase((typename Tbase_::bitem_t*)p, num_items * Titem_size)
{}
/** Copy constructor - make new blob to become copy of the original (source) blob */
FORCEINLINE CBlobT(const Tbase& src) : Tbase(src) {assert((RawSize() % Titem_size) == 0);}
FORCEINLINE CBlobT(const Tbase& src)
: Tbase(src)
{
assert((Tbase::RawSize() % Titem_size) == 0);
}
/** Take ownership constructor */
FORCEINLINE CBlobT(const OnTransfer& ot)
: Tbase(ot.m_pHdr_1)
{}
/** Destructor - ensures that allocated memory (if any) is freed */
FORCEINLINE ~CBlobT() { Free(); }
FORCEINLINE ~CBlobT()
{
Free();
}
/** Check the validity of item index (only in debug mode) */
FORCEINLINE void CheckIdx(int idx) { assert(idx >= 0); assert(idx < Size()); }
FORCEINLINE void CheckIdx(bsize_t idx)
{
assert(idx >= 0); assert(idx < Size());
}
/** Return pointer to the first data item - non-const version */
FORCEINLINE Titem* Data() { return (Titem*)RawData(); }
FORCEINLINE Titem* Data()
{
return (Titem*)Tbase::RawData();
}
/** Return pointer to the first data item - const version */
FORCEINLINE const Titem* Data() const { return (const Titem*)RawData(); }
FORCEINLINE const Titem* Data() const
{
return (const Titem*)Tbase::RawData();
}
/** Return pointer to the idx-th data item - non-const version */
FORCEINLINE Titem* Data(int idx) { CheckIdx(idx); return (Data() + idx); }
FORCEINLINE Titem* Data(bsize_t idx)
{
CheckIdx(idx);
return (Data() + idx);
}
/** Return pointer to the idx-th data item - const version */
FORCEINLINE const Titem* Data(int idx) const { CheckIdx(idx); return (Data() + idx); }
FORCEINLINE const Titem* Data(bsize_t idx) const
{
CheckIdx(idx); return (Data() + idx);
}
/** Return number of items in the Blob */
FORCEINLINE int Size() const { return (RawSize() / Titem_size); }
FORCEINLINE bsize_t Size() const
{
return (Tbase::RawSize() / Titem_size);
}
/** Return total number of items that can fit in the Blob without buffer reallocation */
FORCEINLINE bsize_t MaxSize() const
{
return (Tbase::MaxRawSize() / Titem_size);
}
/** Return number of additional items that can fit in the Blob without buffer reallocation */
FORCEINLINE bsize_t GetReserve() const
{
return ((Tbase::MaxRawSize() - Tbase::RawSize()) / Titem_size);
}
/** Free the memory occupied by Blob destroying all items */
FORCEINLINE void Free()
{
assert((RawSize() % Titem_size) == 0);
int old_size = Size();
assert((Tbase::RawSize() % Titem_size) == 0);
bsize_t old_size = Size();
if (old_size > 0) {
// destroy removed items;
Titem* pI_last_to_destroy = Data(0);
@ -260,27 +428,34 @@ public:
}
Tbase::Free();
}
/** Grow number of data items in Blob by given number - doesn't construct items */
FORCEINLINE Titem* GrowSizeNC(int num_items) { return (Titem*)GrowRawSize(num_items * Titem_size); }
FORCEINLINE Titem* GrowSizeNC(bsize_t num_items)
{
return (Titem*)Tbase::GrowRawSize(num_items * Titem_size);
}
/** Grow number of data items in Blob by given number - constructs new items (using Titem_'s default constructor) */
FORCEINLINE Titem* GrowSizeC(int num_items)
FORCEINLINE Titem* GrowSizeC(bsize_t num_items)
{
Titem* pI = GrowSizeNC(num_items);
for (int i = num_items; i > 0; i--, pI++) new (pI) Titem();
for (bsize_t i = num_items; i > 0; i--, pI++) new (pI) Titem();
}
/** Destroy given number of items and reduce the Blob's data size */
FORCEINLINE void ReduceSize(int num_items)
FORCEINLINE void ReduceSize(bsize_t num_items)
{
assert((RawSize() % Titem_size) == 0);
int old_size = Size();
assert((Tbase::RawSize() % Titem_size) == 0);
bsize_t old_size = Size();
assert(num_items <= old_size);
int new_size = (num_items <= old_size) ? (old_size - num_items) : 0;
bsize_t new_size = (num_items <= old_size) ? (old_size - num_items) : 0;
// destroy removed items;
Titem* pI_last_to_destroy = Data(new_size);
for (Titem* pI = Data(old_size - 1); pI >= pI_last_to_destroy; pI--) pI->~Titem();
// remove them
ReduceRawSize(num_items * Titem_size);
Tbase::ReduceRawSize(num_items * Titem_size);
}
/** Append one data item at the end (calls Titem_'s default constructor) */
FORCEINLINE Titem* AppendNew()
{
@ -288,6 +463,7 @@ public:
Titem* pNewItem = new (&dst) Titem(); // construct the new item by calling in-place new operator
return pNewItem;
}
/** Append the copy of given item at the end of Blob (using copy constructor) */
FORCEINLINE Titem* Append(const Titem& src)
{
@ -295,8 +471,9 @@ public:
Titem* pNewItem = new (&dst) Titem(src); // construct the new item by calling in-place new operator with copy ctor()
return pNewItem;
}
/** Add given items (ptr + number of items) at the end of blob */
FORCEINLINE Titem* Append(const Titem* pSrc, int num_items)
FORCEINLINE Titem* Append(const Titem* pSrc, bsize_t num_items)
{
Titem* pDst = GrowSizeNC(num_items);
Titem* pDstOrg = pDst;
@ -304,14 +481,16 @@ public:
while (pDst < pDstEnd) new (pDst++) Titem(*(pSrc++));
return pDstOrg;
}
/** Remove item with the given index by replacing it by the last item and reducing the size by one */
FORCEINLINE void RemoveBySwap(int idx)
FORCEINLINE void RemoveBySwap(bsize_t idx)
{
CheckIdx(idx);
// destroy removed item
Titem* pRemoved = Data(idx);
RemoveBySwap(pRemoved);
}
/** Remove item given by pointer replacing it by the last item and reducing the size by one */
FORCEINLINE void RemoveBySwap(Titem* pItem)
{
@ -325,20 +504,21 @@ public:
// destroy the last item
pLast->~Titem_();
// and reduce the raw blob size
ReduceRawSize(Titem_size);
Tbase::ReduceRawSize(Titem_size);
}
/** Ensures that given number of items can be added to the end of Blob. Returns pointer to the
* first free (unused) item */
FORCEINLINE Titem* MakeFreeSpace(int num_items) { return (Titem*)MakeRawFreeSpace(num_items * Titem_size); }
};
* first free (unused) item */
FORCEINLINE Titem* MakeFreeSpace(bsize_t num_items)
{
return (Titem*)Tbase::MakeRawFreeSpace(num_items * Titem_size);
}
// simple string implementation
struct CStrA : public CBlobT<char>
{
typedef CBlobT<char> base;
CStrA(const char* str = NULL) {Append(str);}
FORCEINLINE CStrA(const CBlobBaseSimple& src) : base(src) {}
void Append(const char* str) {if (str != NULL && str[0] != '\0') base::Append(str, (int)strlen(str));}
FORCEINLINE OnTransfer Transfer()
{
return OnTransfer(*this);
};
};
#endif /* BLOB_HPP */

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