From: Lars Knoll Date: Sat, 2 Nov 2013 14:01:09 +0000 (+0100) Subject: Better way of handling string additions X-Git-Tag: upstream/5.2.1~64 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=751ec14a5c5332d7ce8a057da853cc809fe2991a;p=platform%2Fupstream%2Fqtdeclarative.git Better way of handling string additions The old algorithm still had some quadratic behavior when adding strings in a loop. This fixes is by keeping track of the longest substring used, as well as the length of the string. If the length is larger then twice the length of the longest substring, we simplify the string. Change-Id: I9d99ae1632a8046ac135e67bdbb448638d15836d Reviewed-by: Simon Hausmann --- diff --git a/src/qml/jsruntime/qv4string.cpp b/src/qml/jsruntime/qv4string.cpp index 016bc38..30b08ba 100644 --- a/src/qml/jsruntime/qv4string.cpp +++ b/src/qml/jsruntime/qv4string.cpp @@ -132,7 +132,7 @@ void String::destroy(Managed *that) void String::markObjects(Managed *that) { String *s = static_cast(that); - if (s->depth) { + if (s->largestSubLength) { s->left->mark(); s->right->mark(); } @@ -251,9 +251,10 @@ bool String::isEqualTo(Managed *t, Managed *o) String::String(ExecutionEngine *engine, const QString &text) : Managed(engine ? engine->emptyClass : 0), _text(const_cast(text).data_ptr()) , identifier(0), stringHash(UINT_MAX) - , depth(0) + , largestSubLength(0) { _text->ref.ref(); + len = _text->size; vtbl = &static_vtbl; type = Type_String; subtype = StringType_Unknown; @@ -262,14 +263,20 @@ String::String(ExecutionEngine *engine, const QString &text) String::String(ExecutionEngine *engine, String *l, String *r) : Managed(engine ? engine->emptyClass : 0) , left(l), right(r) - , stringHash(UINT_MAX), depth(qMax(l->depth, r->depth) + 1) + , stringHash(UINT_MAX), largestSubLength(qMax(l->largestSubLength, r->largestSubLength)) + , len(l->len + r->len) { vtbl = &static_vtbl; type = Type_String; subtype = StringType_Unknown; + if (!l->largestSubLength && l->len > largestSubLength) + largestSubLength = l->len; + if (!r->largestSubLength && r->len > largestSubLength) + largestSubLength = r->len; + // make sure we don't get excessive depth in our strings - if (depth >= 16) + if (len > 256 && len >= 2*largestSubLength) simplifyString(); } @@ -307,15 +314,15 @@ bool String::equals(const StringRef other) const void String::makeIdentifierImpl() const { - if (depth) + if (largestSubLength) simplifyString(); - Q_ASSERT(!depth); + Q_ASSERT(!largestSubLength); engine()->identifierTable->identifier(this); } void String::simplifyString() const { - Q_ASSERT(depth); + Q_ASSERT(largestSubLength); int l = length(); QString result(l, Qt::Uninitialized); @@ -324,12 +331,12 @@ void String::simplifyString() const _text = result.data_ptr(); _text->ref.ref(); identifier = 0; - depth = 0; + largestSubLength = 0; } QChar *String::recursiveAppend(QChar *ch) const { - if (depth) { + if (largestSubLength) { ch = left->recursiveAppend(ch); ch = right->recursiveAppend(ch); } else { @@ -342,9 +349,9 @@ QChar *String::recursiveAppend(QChar *ch) const void String::createHashValue() const { - if (depth) + if (largestSubLength) simplifyString(); - Q_ASSERT(!depth); + Q_ASSERT(!largestSubLength); const QChar *ch = reinterpret_cast(_text->data()); const QChar *end = ch + _text->size; diff --git a/src/qml/jsruntime/qv4string_p.h b/src/qml/jsruntime/qv4string_p.h index ba2bc0d..5412371 100644 --- a/src/qml/jsruntime/qv4string_p.h +++ b/src/qml/jsruntime/qv4string_p.h @@ -62,12 +62,12 @@ struct Q_QML_EXPORT String : public Managed { String() : Managed(0), _text(QStringData::sharedNull()), identifier(0) - , stringHash(UINT_MAX), depth(0) + , stringHash(UINT_MAX), largestSubLength(0), len(0) { vtbl = &static_vtbl; type = Type_String; subtype = StringType_Unknown; } String(ExecutionEngine *engine, const QString &text); String(ExecutionEngine *engine, String *l, String *n); ~String() { - if (!depth && !_text->ref.deref()) + if (!largestSubLength && !_text->ref.deref()) QStringData::deallocate(_text); _data = 0; } @@ -78,7 +78,7 @@ struct Q_QML_EXPORT String : public Managed { return true; if (hashValue() != other->hashValue()) return false; - Q_ASSERT(!depth); + Q_ASSERT(!largestSubLength); if (identifier && identifier == other->identifier) return true; if (subtype >= StringType_UInt && subtype == other->subtype) @@ -90,9 +90,8 @@ struct Q_QML_EXPORT String : public Managed { return toQString() < other->toQString(); } - inline bool isEmpty() const { return _text && !_text->size; } inline QString toQString() const { - if (depth) + if (largestSubLength) simplifyString(); QStringDataPtr ptr = { _text }; _text->ref.ref(); @@ -104,14 +103,14 @@ struct Q_QML_EXPORT String : public Managed { inline unsigned hashValue() const { if (subtype == StringType_Unknown) createHashValue(); - Q_ASSERT(!depth); + Q_ASSERT(!largestSubLength); return stringHash; } uint asArrayIndex() const { if (subtype == StringType_Unknown) createHashValue(); - Q_ASSERT(!depth); + Q_ASSERT(!largestSubLength); if (subtype == StringType_ArrayIndex) return stringHash; return UINT_MAX; @@ -132,14 +131,13 @@ struct Q_QML_EXPORT String : public Managed { bool startsWithUpper() const { const String *l = this; - while (l->depth) + while (l->largestSubLength) l = l->left; return l->_text->size && QChar::isUpper(l->_text->data()[0]); } int length() const { - if (!depth) - return _text->size; - return left->length() + right->length(); + Q_ASSERT((largestSubLength && (len == left->len + right->len)) || len == (uint)_text->size); + return len; } union { @@ -151,7 +149,8 @@ struct Q_QML_EXPORT String : public Managed { mutable String *right; }; mutable uint stringHash; - mutable uint depth; + mutable uint largestSubLength; + uint len; protected: diff --git a/src/qml/qml/qqmllocale.cpp b/src/qml/qml/qqmllocale.cpp index 81a6ffc..b92b3e4 100644 --- a/src/qml/qml/qqmllocale.cpp +++ b/src/qml/qml/qqmllocale.cpp @@ -437,7 +437,7 @@ QV4::ReturnedValue QQmlNumberExtension::method_toLocaleString(QV4::SimpleCallCon if (!ctx->callData->args[1].isString()) V4THROW_ERROR("Locale: Number.toLocaleString(): Invalid arguments"); QV4::String *fs = ctx->callData->args[1].toString(ctx); - if (!fs->isEmpty()) + if (fs->length()) format = fs->toQString().at(0).unicode(); } int prec = 2; @@ -501,7 +501,7 @@ QV4::ReturnedValue QQmlNumberExtension::method_fromLocaleString(QV4::SimpleCallC } QV4::String *ns = ctx->callData->args[numberIdx].toString(ctx); - if (ns->isEmpty()) + if (!ns->length()) return QV4::Encode(Q_QNAN); bool ok = false;