90 lines
2.4 KiB
C++
90 lines
2.4 KiB
C++
// © 2016 and later: Unicode, Inc. and others.
|
|
// License & terms of use: http://www.unicode.org/copyright.html
|
|
/*
|
|
******************************************************************************
|
|
* Copyright (C) 2015, International Business Machines Corporation and
|
|
* others. All Rights Reserved.
|
|
******************************************************************************
|
|
*
|
|
* File unistrappender.h
|
|
******************************************************************************
|
|
*/
|
|
|
|
#ifndef __UNISTRAPPENDER_H__
|
|
#define __UNISTRAPPENDER_H__
|
|
|
|
#include "unicode/unistr.h"
|
|
#include "unicode/uobject.h"
|
|
#include "unicode/utf16.h"
|
|
#include "unicode/utypes.h"
|
|
#include "cmemory.h"
|
|
|
|
U_NAMESPACE_BEGIN
|
|
|
|
/**
|
|
* An optimization for the slowness of calling UnicodeString::append()
|
|
* one character at a time in a loop. It stores appends in a buffer while
|
|
* never actually calling append on the unicode string unless the buffer
|
|
* fills up or is flushed.
|
|
*
|
|
* proper usage:
|
|
* {
|
|
* UnicodeStringAppender appender(astring);
|
|
* for (int32_t i = 0; i < 100; ++i) {
|
|
* appender.append((UChar) i);
|
|
* }
|
|
* // appender flushed automatically when it goes out of scope.
|
|
* }
|
|
*/
|
|
class UnicodeStringAppender : public UMemory {
|
|
public:
|
|
|
|
/**
|
|
* dest is the UnicodeString being appended to. It must always
|
|
* exist while this instance exists.
|
|
*/
|
|
UnicodeStringAppender(UnicodeString &dest) : fDest(&dest), fIdx(0) { }
|
|
|
|
inline void append(UChar x) {
|
|
if (fIdx == UPRV_LENGTHOF(fBuffer)) {
|
|
fDest->append(fBuffer, 0, fIdx);
|
|
fIdx = 0;
|
|
}
|
|
fBuffer[fIdx++] = x;
|
|
}
|
|
|
|
inline void append(UChar32 x) {
|
|
if (fIdx >= UPRV_LENGTHOF(fBuffer) - 1) {
|
|
fDest->append(fBuffer, 0, fIdx);
|
|
fIdx = 0;
|
|
}
|
|
U16_APPEND_UNSAFE(fBuffer, fIdx, x);
|
|
}
|
|
|
|
/**
|
|
* Ensures that all appended characters have been written out to dest.
|
|
*/
|
|
inline void flush() {
|
|
if (fIdx) {
|
|
fDest->append(fBuffer, 0, fIdx);
|
|
}
|
|
fIdx = 0;
|
|
}
|
|
|
|
/**
|
|
* flush the buffer when we go out of scope.
|
|
*/
|
|
~UnicodeStringAppender() {
|
|
flush();
|
|
}
|
|
private:
|
|
UnicodeString *fDest;
|
|
int32_t fIdx;
|
|
UChar fBuffer[32];
|
|
UnicodeStringAppender(const UnicodeStringAppender &other);
|
|
UnicodeStringAppender &operator=(const UnicodeStringAppender &other);
|
|
};
|
|
|
|
U_NAMESPACE_END
|
|
|
|
#endif
|