Move utilities to core/utils folder.

Also move the names to Utils namespace.

src/core/utils/string.cpp

@@ -29,15 +29,106 @@
 
 #include <QByteArray>
 #include <QString>
+#include <QLocale>
+#include <cmath>
 #include "string.h"
 
-QString String::fromStdString(const std::string &str)
+QString Utils::String::fromStdString(const std::string &str)
 {
     return QString::fromUtf8(str.c_str());
 }
 
-std::string String::toStdString(const QString &str)
+std::string Utils::String::toStdString(const QString &str)
 {
     QByteArray utf8 = str.toUtf8();
     return std::string(utf8.constData(), utf8.length());
 }
+
+// uses lessThan comparison
+bool Utils::String::naturalSort(QString left, QString right, bool &result)
+{
+    // Return value indicates if functions was successful
+    // result argument will contain actual comparison result if function was successful
+    int posL = 0;
+    int posR = 0;
+    do {
+        forever {
+            if (posL == left.size() || posR == right.size())
+                return false; // No data
+
+            QChar leftChar = left.at(posL);
+            QChar rightChar = right.at(posR);
+            bool leftCharIsDigit = leftChar.isDigit();
+            bool rightCharIsDigit = rightChar.isDigit();
+            if (leftCharIsDigit != rightCharIsDigit)
+                return false; // Digit positions mismatch
+
+            if (leftCharIsDigit)
+                break; // Both are digit, break this loop and compare numbers
+
+            if (leftChar != rightChar)
+                return false; // Strings' subsets before digit do not match
+
+            ++posL;
+            ++posR;
+        }
+
+        QString temp;
+        while (posL < left.size()) {
+            if (left.at(posL).isDigit())
+                temp += left.at(posL);
+            else
+                break;
+            posL++;
+        }
+        int numL = temp.toInt();
+        temp.clear();
+
+        while (posR < right.size()) {
+            if (right.at(posR).isDigit())
+                temp += right.at(posR);
+            else
+                break;
+            posR++;
+        }
+        int numR = temp.toInt();
+
+        if (numL != numR) {
+            result = (numL < numR);
+            return true;
+        }
+
+        // Strings + digits do match and we haven't hit string end
+        // Do another round
+
+    } while (true);
+
+    return false;
+}
+
+// to send numbers instead of strings with suffixes
+QString Utils::String::fromDouble(double n, int precision)
+{
+    /* HACK because QString rounds up. Eg QString::number(0.999*100.0, 'f' ,1) == 99.9
+    ** but QString::number(0.9999*100.0, 'f' ,1) == 100.0 The problem manifests when
+    ** the number has more digits after the decimal than we want AND the digit after
+    ** our 'wanted' is >= 5. In this case our last digit gets rounded up. So for each
+    ** precision we add an extra 0 behind 1 in the below algorithm. */
+
+    double prec = std::pow(10.0, precision);
+    return QLocale::system().toString(std::floor(n * prec) / prec, 'f', precision);
+}
+
+// Implements constant-time comparison to protect against timing attacks
+// Taken from https://crackstation.net/hashing-security.htm
+bool Utils::String::slowEquals(const QByteArray &a, const QByteArray &b)
+{
+    int lengthA = a.length();
+    int lengthB = b.length();
+
+    int diff = lengthA ^ lengthB;
+    for (int i = 0; (i < lengthA) && (i < lengthB); i++)
+        diff |= a[i] ^ b[i];
+
+    return (diff == 0);
+}