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[fbreader] Optimized ZLUnicodeUtil::toLower and toUpper for ASCII

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Performance analysis shows that UTF8->UCS4->UTF8 conversion takes
noticeable amount of CPU time. For ASCII strings it's unnecessary.
This commit is contained in:
Slava Monich 2015-07-29 18:43:31 +03:00
parent 61adf35e4f
commit 4026ae35d1
1 changed files with 26 additions and 12 deletions
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30
fbreader/fbreader/zlibrary/core/src/util/ZLUnicodeUtil.cpp
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@ -450,13 +450,20 @@ void ZLUnicodeUtil::toLower(Ucs4String &str) {
}
std::string ZLUnicodeUtil::toLower(const std::string &utf8String) {
std::string result;
const int utf8Len = utf8String.length();
if (utf8Length(utf8String) == utf8Len) {
// ASCII string
result.reserve(utf8Len);
for (std::string::const_iterator it = utf8String.begin(); it != utf8String.end(); ++it) {
result.append(1, tolower(*it));
}
} else {
Ucs4String ucs4String;
utf8ToUcs4(ucs4String, utf8String);
toLower(ucs4String);
std::string result;
ucs4ToUtf8(result, ucs4String, utf8String.length());
ucs4ToUtf8(result, ucs4String, utf8Len);
}
return result;
}
@ -473,12 +480,19 @@ void ZLUnicodeUtil::toUpper(Ucs4String &str) {
}
std::string ZLUnicodeUtil::toUpper(const std::string &utf8String) {
std::string result;
const int utf8Len = utf8String.length();
if (utf8Length(utf8String) == utf8Len) {
// ASCII string
result.reserve(utf8Len);
for (std::string::const_iterator it = utf8String.begin(); it != utf8String.end(); ++it) {
result.append(1, toupper(*it));
}
} else {
Ucs4String ucs4String;
utf8ToUcs4(ucs4String, utf8String);
toUpper(ucs4String);
std::string result;
ucs4ToUtf8(result, ucs4String, utf8String.length());
ucs4ToUtf8(result, ucs4String, utf8Len);
}
return result;
}