使用ICU剥离变音符号的代码

Question

有人可以提供一些示例代码来剥离变音符号(即,替换具有重音符号,变音符号等的字符,以及它们的无重音,无语音等字符等价物,例如,每个重音符é将成为纯ASCII e)来自UnicodeString使用C++中的ICU库？例如:

UnicodeString strip_diacritics( UnicodeString const &s ) {
    UnicodeString result;
    // ...
    return result;
}

假设s已经规范化了.谢谢.

Answer 1

ICU允许您使用特定规则来音译字符串.我的规则是NFD; [:M:] Remove; NFC:分解,删除变音符号,重构.以下代码将UTF-8 std::string作为输入并返回另一个UTF-8 std::string:

#include <unicode/utypes.h>
#include <unicode/unistr.h>
#include <unicode/translit.h>

std::string desaxUTF8(const std::string& str) {
    // UTF-8 std::string -> UTF-16 UnicodeString
    UnicodeString source = UnicodeString::fromUTF8(StringPiece(str));

    // Transliterate UTF-16 UnicodeString
    UErrorCode status = U_ZERO_ERROR;
    Transliterator *accentsConverter = Transliterator::createInstance(
        "NFD; [:M:] Remove; NFC", UTRANS_FORWARD, status);
    accentsConverter->transliterate(source);
    // TODO: handle errors with status

    // UTF-16 UnicodeString -> UTF-8 std::string
    std::string result;
    source.toUTF8String(result);

    return result;
}

Answer 2

在其他地方进行更多搜索后：

UErrorCode status = U_ZERO_ERROR;
UnicodeString result;

// 's16' is the UTF-16 string to have diacritics removed
Normalizer::normalize( s16, UNORM_NFKD, 0, result, status );
if ( U_FAILURE( status ) )
  // complain

// code to convert UTF-16 's16' to UTF-8 std::string 's8' elided

string buf8;
buf8.reserve( s8.length() );
for ( string::const_iterator i = s8.begin(); i != s8.end(); ++i ) {
  char const c = *i;
  if ( isascii( c ) )
    buf8.push_back( c );
}
// result is in buf8

这是 O(n)。