// the implementation is from dsljson, it is the fastest although has the risk not matching field strictly

public static String genObjectUsingHash(Class clazz, ClassDescriptor desc) {

StringBuilder lines = new StringBuilder();

// === if null, return null

append(lines, "java.lang.Object existingObj = com.jsoniter.CodegenAccess.resetExistingObject(iter);");

append(lines, "byte nextToken = com.jsoniter.CodegenAccess.readByte(iter);");

append(lines, "if (nextToken != '{') {");

append(lines, "if (nextToken == 'n') {");

append(lines, "com.jsoniter.CodegenAccess.skipFixedBytes(iter, 3);");

append(lines, "return null;");

append(lines, "} else {");

append(lines, "nextToken = com.jsoniter.CodegenAccess.nextToken(iter);");

append(lines, "if (nextToken == 'n') {");

append(lines, "com.jsoniter.CodegenAccess.skipFixedBytes(iter, 3);");

append(lines, "return null;");

append(lines, "}");

append(lines, "} // end of if null");

append(lines, "} // end of if {");

// === if empty, return empty

// ctor requires binding

for (Binding parameter : desc.ctor.parameters) {

appendVarDef(lines, parameter);

}

append(lines, "nextToken = com.jsoniter.CodegenAccess.readByte(iter);");

append(lines, "if (nextToken != '\"') {");

append(lines, "if (nextToken == '}') {");

append(lines, "return {{newInst}};");

append(lines, "} else {");

append(lines, "nextToken = com.jsoniter.CodegenAccess.nextToken(iter);");

append(lines, "if (nextToken == '}') {");

append(lines, "return {{newInst}};");

append(lines, "} else {");

append(lines, "com.jsoniter.CodegenAccess.unreadByte(iter);");

append(lines, "}");

append(lines, "} // end of if end");

append(lines, "} else { com.jsoniter.CodegenAccess.unreadByte(iter); }// end of if not quote");

for (Binding field : desc.fields) {

appendVarDef(lines, field);

}

for (Binding setter : desc.setters) {

appendVarDef(lines, setter);

}

for (WrapperDescriptor setter : desc.wrappers) {

for (Binding param : setter.parameters) {

appendVarDef(lines, param);

}

}

// === bind fields

HashSet<Integer> knownHashes = new HashSet<Integer>();

HashMap<String, Binding> bindings = new HashMap<String, Binding>();

for (Binding binding : desc.allDecoderBindings()) {

for (String fromName : binding.fromNames) {

bindings.put(fromName, binding);

}

}

ArrayList<String> fromNames = new ArrayList<String>(bindings.keySet());

Collections.sort(fromNames, new Comparator<String>() {

@Override

public int compare(String o1, String o2) {

int x = calcHash(o1);

int y = calcHash(o2);

return (x < y) ? -1 : ((x == y) ? 0 : 1);

}

});

// === bind more fields

append(lines, "do {");

append(lines, "switch (com.jsoniter.CodegenAccess.readObjectFieldAsHash(iter)) {");

for (String fromName : fromNames) {

int intHash = calcHash(fromName);

if (intHash == 0) {

// hash collision, 0 can not be used as sentinel

return CodegenImplObjectStrict.genObjectUsingStrict(clazz, desc);

}

if (knownHashes.contains(intHash)) {

// hash collision with other field can not be used as sentinel

return CodegenImplObjectStrict.genObjectUsingStrict(clazz, desc);

}

knownHashes.add(intHash);

append(lines, "case " + intHash + ": ");

appendBindingSet(lines, desc, bindings.get(fromName));

append(lines, "continue;");

}

append(lines, "}");

append(lines, "iter.skip();");

append(lines, "} while (com.jsoniter.CodegenAccess.nextTokenIsComma(iter));");

append(lines, CodegenImplNative.getTypeName(clazz) + " obj = {{newInst}};");

for (Binding field : desc.fields) {

append(lines, String.format("obj.%s = _%s_;", field.field.getName(), field.name));

}

for (Binding setter : desc.setters) {

append(lines, String.format("obj.%s(_%s_);", setter.method.getName(), setter.name));

}

appendWrappers(desc.wrappers, lines);

append(lines, "return obj;");

return lines.toString()

.replace("{{clazz}}", clazz.getCanonicalName())

.replace("{{newInst}}", genNewInstCode(clazz, desc.ctor));

}

public static int calcHash(String fromName) {

long hash = 0x811c9dc5;

for (byte b : fromName.getBytes()) {

hash ^= b;

hash *= 0x1000193;

}

return (int) hash;

}

private static void appendBindingSet(StringBuilder lines, ClassDescriptor desc, Binding binding) {

append(lines, String.format("_%s_ = %s;", binding.name, CodegenImplNative.genField(binding)));

}

static void appendWrappers(List<WrapperDescriptor> wrappers, StringBuilder lines) {

for (WrapperDescriptor wrapper : wrappers) {

lines.append("obj.");

lines.append(wrapper.method.getName());

appendInvocation(lines, wrapper.parameters);

lines.append(";\n");

}

}

static void appendVarDef(StringBuilder lines, Binding parameter) {

String typeName = CodegenImplNative.getTypeName(parameter.valueType);

append(lines, String.format("%s _%s_ = %s;", typeName, parameter.name, CodegenImplObjectStrict.DEFAULT_VALUES.get(typeName)));

}

static String genNewInstCode(Class clazz, ConstructorDescriptor ctor) {

StringBuilder code = new StringBuilder();

if (ctor.parameters.isEmpty()) {

// nothing to bind, safe to reuse existing object

code.append("(existingObj == null ? ");

}

if (ctor.objectFactory != null) {

code.append(String.format("(%s)com.jsoniter.spi.JsoniterSpi.create(%s.class)",

clazz.getCanonicalName(), clazz.getCanonicalName()));

} else {

if (ctor.staticMethodName == null) {

code.append(String.format("new %s", clazz.getCanonicalName()));

} else {

code.append(String.format("%s.%s", clazz.getCanonicalName(), ctor.staticMethodName));

}

}

List<Binding> params = ctor.parameters;

if (ctor.objectFactory == null) {

appendInvocation(code, params);

}

if (ctor.parameters.isEmpty()) {

// nothing to bind, safe to reuse existing obj

code.append(String.format(" : (%s)existingObj)", clazz.getCanonicalName()));

}

return code.toString();

}

private static void appendInvocation(StringBuilder code, List<Binding> params) {

code.append("(");

boolean isFirst = true;

for (Binding ctorParam : params) {

if (isFirst) {

isFirst = false;

} else {

code.append(",");

}

code.append(String.format("_%s_", ctorParam.name));

}

code.append(")");

}

static void append(StringBuilder lines, String str) {

lines.append(str);

lines.append("\n");

}