PICout::withExternalBufferAnd decomposed to PICout::withExternalBufferAndID and PICout::withExternalBufferAnd

PIString::toPercentageEncoding/fromPercentageEncoding
piStringify()
PIHTTPClient support arguments
some doc

libs/main/text/pistring.cpp

@@ -1810,6 +1810,46 @@ PIString & PIString::setReadableSize(llong bytes) {
 }
 
 
+PIString PIString::toPercentageEncoding() const {
+	static const PIString valid = "-._~"_a;
+	PIString ret;
+	PIByteArray utf8;
+	bool ok = false;
+	for (const auto & c: *this) {
+		ok = false;
+		if (c.isAscii()) {
+			if (c.isAlpha() || c.isDigit())
+				ok = true;
+			else if (valid.contains(c))
+				ok = true;
+		}
+		if (ok) {
+			ret.append(c);
+		} else {
+			utf8 = PIString(c).toUTF8();
+			for (auto u: utf8)
+				ret.append('%').append(PIString::fromNumber(u, 16).expandLeftTo(2, '0'));
+		}
+	}
+	return ret;
+}
+
+
+PIString PIString::fromPercentageEncoding(const PIString & in) {
+	PIByteArray utf8;
+	PIChar c;
+	for (int i = 0; i < in.size_s(); ++i) {
+		c = in[i];
+		if (c == '%') {
+			utf8 << static_cast<uchar>(in.mid(i + 1, 2).toInt(16));
+			i += 2;
+		} else
+			utf8 << static_cast<uchar>(c.toAscii());
+	}
+	return PIString::fromUTF8(utf8);
+}
+
+
 PIString & PIString::arg(const PIString & v) {
 	auto ph = minArgPlaceholder();
 	if (!ph.isEmpty()) replaceAll(ph, v);