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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /intl/icu/source/common/unistrappender.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-upstream.tar.xz firefox-esr-upstream.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'intl/icu/source/common/unistrappender.h')
-rw-r--r-- | intl/icu/source/common/unistrappender.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/intl/icu/source/common/unistrappender.h b/intl/icu/source/common/unistrappender.h new file mode 100644 index 0000000000..ac49b5f2f9 --- /dev/null +++ b/intl/icu/source/common/unistrappender.h @@ -0,0 +1,90 @@ +// © 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((char16_t) 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(char16_t 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; + char16_t fBuffer[32]; + UnicodeStringAppender(const UnicodeStringAppender &other); + UnicodeStringAppender &operator=(const UnicodeStringAppender &other); +}; + +U_NAMESPACE_END + +#endif |