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Poco::Buffer properly handles zero-sized buffers

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This commit is contained in:
Guenter Obiltschnig
2014-10-09 10:34:46 +02:00
parent 1d7d57a321
commit 5b0fa2e06a
1 changed files with 29 additions and 17 deletions
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46
Foundation/include/Poco/Buffer.h
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@@ -41,10 +41,14 @@ public:
Buffer(std::size_t capacity): Buffer(std::size_t capacity):
_capacity(capacity), _capacity(capacity),
_used(capacity), _used(capacity),
_ptr(new T[capacity]), _ptr(0),
_ownMem(true) _ownMem(true)
/// Creates and allocates the Buffer. /// Creates and allocates the Buffer.
{ {
if (capacity > 0)
{
_ptr = new T[capacity];
}
} }
Buffer(T* pMem, std::size_t length): Buffer(T* pMem, std::size_t length):
@@ -64,26 +68,32 @@ public:
Buffer(const T* pMem, std::size_t length): Buffer(const T* pMem, std::size_t length):
_capacity(length), _capacity(length),
_used(length), _used(length),
_ptr(new T[length]), _ptr(0),
_ownMem(true) _ownMem(true)
/// Creates and allocates the Buffer; copies the contents of /// Creates and allocates the Buffer; copies the contents of
/// the supplied memory into the buffer. Length argument specifies /// the supplied memory into the buffer. Length argument specifies
/// the length of the supplied memory pointed to by pMem in the /// the length of the supplied memory pointed to by pMem in the
/// number of elements of type T. /// number of elements of type T.
{ {
if (_used) if (_capacity > 0)
{
_ptr = new T[_capacity];
std::memcpy(_ptr, pMem, _used * sizeof(T)); std::memcpy(_ptr, pMem, _used * sizeof(T));
}
} }
Buffer(const Buffer& other): Buffer(const Buffer& other):
/// Copy constructor. /// Copy constructor.
_capacity(other._used), _capacity(other._used),
_used(other._used), _used(other._used),
_ptr(new T[other._used]), _ptr(0),
_ownMem(true) _ownMem(true)
{ {
if (_used) if (_used)
{
_ptr = new T[_used];
std::memcpy(_ptr, other._ptr, _used * sizeof(T)); std::memcpy(_ptr, other._ptr, _used * sizeof(T));
}
} }
Buffer& operator = (const Buffer& other) Buffer& operator = (const Buffer& other)
@@ -115,15 +125,15 @@ public:
/// resized. If resize is attempted on those, IllegalAccessException /// resized. If resize is attempted on those, IllegalAccessException
/// is thrown. /// is thrown.
{ {
if (!_ownMem) if (!_ownMem) throw Poco::InvalidAccessException("Cannot resize buffer which does not own its storage.");
throw Poco::InvalidAccessException("Cannot resize buffer which does not own its storage.");
if (newCapacity > _capacity) if (newCapacity > _capacity)
{ {
T* ptr = new T[newCapacity]; T* ptr = new T[newCapacity];
if (preserveContent) if (preserveContent)
{
std::memcpy(ptr, _ptr, _used * sizeof(T)); std::memcpy(ptr, _ptr, _used * sizeof(T));
}
delete [] _ptr; delete [] _ptr;
_ptr = ptr; _ptr = ptr;
_capacity = newCapacity; _capacity = newCapacity;
@@ -144,18 +154,20 @@ public:
/// resized. If resize is attempted on those, IllegalAccessException /// resized. If resize is attempted on those, IllegalAccessException
/// is thrown. /// is thrown.
{ {
if (!_ownMem) if (!_ownMem) throw Poco::InvalidAccessException("Cannot resize buffer which does not own its storage.");
throw Poco::InvalidAccessException("Cannot resize buffer which does not own its storage.");
if (newCapacity != _capacity) if (newCapacity != _capacity)
{ {
T* ptr = new T[newCapacity]; T* ptr = 0;
if (preserveContent) if (newCapacity > 0)
{ {
std::size_t newSz = _used < newCapacity ? _used : newCapacity; ptr = new T[newCapacity];
std::memcpy(ptr, _ptr, newSz * sizeof(T)); if (preserveContent)
{
std::size_t newSz = _used < newCapacity ? _used : newCapacity;
std::memcpy(ptr, _ptr, newSz * sizeof(T));
}
} }
delete [] _ptr; delete [] _ptr;
_ptr = ptr; _ptr = ptr;
_capacity = newCapacity; _capacity = newCapacity;
@@ -217,7 +229,7 @@ public:
swap(_used, other._used); swap(_used, other._used);
} }
bool operator ==(const Buffer& other) const bool operator == (const Buffer& other) const
/// Compare operator. /// Compare operator.
{ {
if (this != &other) if (this != &other)
@@ -235,14 +247,14 @@ public:
return true; return true;
} }
bool operator !=(const Buffer& other) const bool operator != (const Buffer& other) const
/// Compare operator. /// Compare operator.
{ {
return !(*this == other); return !(*this == other);
} }
void clear() void clear()
/// Sets the contents of the bufer to zero. /// Sets the contents of the buffer to zero.
{ {
std::memset(_ptr, 0, _used * sizeof(T)); std::memset(_ptr, 0, _used * sizeof(T));
} }