=min_capacity.
* May return a pointer to the caller-owned scratch buffer which must have
* scratch_capacity>=min_capacity.
* The returned buffer is only valid until the next operation
* on this ByteSink.
*
* After writing at most *result_capacity bytes, call Append() with the
* pointer returned from this function and the number of bytes written.
* Many Append() implementations will avoid copying bytes if this function
* returned an internal buffer.
*
* Partial usage example:
* int32_t capacity;
* char* buffer = sink->GetAppendBuffer(..., &capacity);
* ... Write n bytes into buffer, with n <= capacity.
* sink->Append(buffer, n);
* In many implementations, that call to Append will avoid copying bytes.
*
* If the ByteSink allocates or reallocates an internal buffer, it should use
* the desired_capacity_hint if appropriate.
* If a caller cannot provide a reasonable guess at the desired capacity,
* it should pass desired_capacity_hint=0.
*
* If a non-scratch buffer is returned, the caller may only pass
* a prefix to it to Append().
* That is, it is not correct to pass an interior pointer to Append().
*
* The default implementation always returns the scratch buffer.
*
* @param min_capacity required minimum capacity of the returned buffer;
* must be non-negative
* @param desired_capacity_hint desired capacity of the returned buffer;
* must be non-negative
* @param scratch default caller-owned buffer
* @param scratch_capacity capacity of the scratch buffer
* @param result_capacity pointer to an integer which will be set to the
* capacity of the returned buffer
* @return a buffer with *result_capacity>=min_capacity
* @stable ICU 4.2
*/
virtual char* GetAppendBuffer(int32_t min_capacity,
int32_t desired_capacity_hint,
char* scratch, int32_t scratch_capacity,
int32_t* result_capacity);
/**
* Flush internal buffers.
* Some byte sinks use internal buffers or provide buffering
* and require calling Flush() at the end of the stream.
* The ByteSink should be ready for further Append() calls after Flush().
* The default implementation of Flush() does nothing.
* @stable ICU 4.2
*/
virtual void Flush();
private:
ByteSink(const ByteSink &); // copy constructor not implemented
ByteSink &operator=(const ByteSink &); // assignment operator not implemented
};
// -------------------------------------------------------------
// Some standard implementations
/**
* Implementation of ByteSink that writes to a flat byte array,
* with bounds-checking:
* This sink will not write more than capacity bytes to outbuf.
* If more than capacity bytes are Append()ed, then excess bytes are ignored,
* and Overflowed() will return true.
* Overflow does not cause a runtime error.
* @stable ICU 4.2
*/
class U_COMMON_API CheckedArrayByteSink : public ByteSink {
public:
/**
* Constructs a ByteSink that will write to outbuf[0..capacity-1].
* @param outbuf buffer to write to
* @param capacity size of the buffer
* @stable ICU 4.2
*/
CheckedArrayByteSink(char* outbuf, int32_t capacity);
/**
* Destructor.
* @stable ICU 4.2
*/
virtual ~CheckedArrayByteSink();
/**
* Returns the sink to its original state, without modifying the buffer.
* Useful for reusing both the buffer and the sink for multiple streams.
* Resets the state to NumberOfBytesWritten()=NumberOfBytesAppended()=0
* and Overflowed()=FALSE.
* @return *this
* @stable ICU 4.6
*/
virtual CheckedArrayByteSink& Reset();
/**
* Append "bytes[0,n-1]" to this.
* @param bytes the pointer to the bytes
* @param n the number of bytes; must be non-negative
* @stable ICU 4.2
*/
virtual void Append(const char* bytes, int32_t n);
/**
* Returns a writable buffer for appending and writes the buffer's capacity to
* *result_capacity. For details see the base class documentation.
* @param min_capacity required minimum capacity of the returned buffer;
* must be non-negative
* @param desired_capacity_hint desired capacity of the returned buffer;
* must be non-negative
* @param scratch default caller-owned buffer
* @param scratch_capacity capacity of the scratch buffer
* @param result_capacity pointer to an integer which will be set to the
* capacity of the returned buffer
* @return a buffer with *result_capacity>=min_capacity
* @stable ICU 4.2
*/
virtual char* GetAppendBuffer(int32_t min_capacity,
int32_t desired_capacity_hint,
char* scratch, int32_t scratch_capacity,
int32_t* result_capacity);
/**
* Returns the number of bytes actually written to the sink.
* @return number of bytes written to the buffer
* @stable ICU 4.2
*/
int32_t NumberOfBytesWritten() const { return size_; }
/**
* Returns true if any bytes were discarded, i.e., if there was an
* attempt to write more than 'capacity' bytes.
* @return TRUE if more than 'capacity' bytes were Append()ed
* @stable ICU 4.2
*/
UBool Overflowed() const { return overflowed_; }
/**
* Returns the number of bytes appended to the sink.
* If Overflowed() then NumberOfBytesAppended()>NumberOfBytesWritten()
* else they return the same number.
* @return number of bytes written to the buffer
* @stable ICU 4.6
*/
int32_t NumberOfBytesAppended() const { return appended_; }
private:
char* outbuf_;
const int32_t capacity_;
int32_t size_;
int32_t appended_;
UBool overflowed_;
CheckedArrayByteSink(); ///< default constructor not implemented
CheckedArrayByteSink(const CheckedArrayByteSink &); ///< copy constructor not implemented
CheckedArrayByteSink &operator=(const CheckedArrayByteSink &); ///< assignment operator not implemented
};
#if U_HAVE_STD_STRING
/**
* Implementation of ByteSink that writes to a "string".
* The StringClass is usually instantiated with a std::string.
* @stable ICU 4.2
*/
template
class StringByteSink : public ByteSink {
public:
/**
* Constructs a ByteSink that will append bytes to the dest string.
* @param dest pointer to string object to append to
* @stable ICU 4.2
*/
StringByteSink(StringClass* dest) : dest_(dest) { }
/**
* Append "bytes[0,n-1]" to this.
* @param data the pointer to the bytes
* @param n the number of bytes; must be non-negative
* @stable ICU 4.2
*/
virtual void Append(const char* data, int32_t n) { dest_->append(data, n); }
private:
StringClass* dest_;
StringByteSink(); ///< default constructor not implemented
StringByteSink(const StringByteSink &); ///< copy constructor not implemented
StringByteSink &operator=(const StringByteSink &); ///< assignment operator not implemented
};
#endif
U_NAMESPACE_END
#endif // __BYTESTREAM_H__