NOISSUE reorganize and document libraries

8 files changed, 968 insertions, 0 deletions

diff --git a/libraries/classparser/src/annotations.cpp b/libraries/classparser/src/annotations.cpp
new file mode 100644
index 00000000..d1a7c046
--- /dev/null
+++ b/libraries/classparser/src/annotations.cpp
@@ -0,0 +1,85 @@
+#include "classfile.h"
+#include "annotations.h"
+#include <sstream>
+
+namespace java
+{
+std::string annotation::toString()
+{
+	std::ostringstream ss;
+	ss << "Annotation type : " << type_index << " - " << pool[type_index].str_data << std::endl;
+	ss << "Contains " << name_val_pairs.size() << " pairs:" << std::endl;
+	for (unsigned i = 0; i < name_val_pairs.size(); i++)
+	{
+		std::pair<uint16_t, element_value *> &val = name_val_pairs[i];
+		auto name_idx = val.first;
+		ss << pool[name_idx].str_data << "(" << name_idx << ")"
+		   << " = " << val.second->toString() << std::endl;
+	}
+	return ss.str();
+}
+
+annotation *annotation::read(util::membuffer &input, constant_pool &pool)
+{
+	uint16_t type_index = 0;
+	input.read_be(type_index);
+	annotation *ann = new annotation(type_index, pool);
+
+	uint16_t num_pairs = 0;
+	input.read_be(num_pairs);
+	while (num_pairs)
+	{
+		uint16_t name_idx = 0;
+		// read name index
+		input.read_be(name_idx);
+		auto elem = element_value::readElementValue(input, pool);
+		// read value
+		ann->add_pair(name_idx, elem);
+		num_pairs--;
+	}
+	return ann;
+}
+
+element_value *element_value::readElementValue(util::membuffer &input,
+											   java::constant_pool &pool)
+{
+	element_value_type type = INVALID;
+	input.read(type);
+	uint16_t index = 0;
+	uint16_t index2 = 0;
+	std::vector<element_value *> vals;
+	switch (type)
+	{
+	case PRIMITIVE_BYTE:
+	case PRIMITIVE_CHAR:
+	case PRIMITIVE_DOUBLE:
+	case PRIMITIVE_FLOAT:
+	case PRIMITIVE_INT:
+	case PRIMITIVE_LONG:
+	case PRIMITIVE_SHORT:
+	case PRIMITIVE_BOOLEAN:
+	case STRING:
+		input.read_be(index);
+		return new element_value_simple(type, index, pool);
+	case ENUM_CONSTANT:
+		input.read_be(index);
+		input.read_be(index2);
+		return new element_value_enum(type, index, index2, pool);
+	case CLASS: // Class
+		input.read_be(index);
+		return new element_value_class(type, index, pool);
+	case ANNOTATION: // Annotation
+		// FIXME: runtime visibility info needs to be passed from parent
+		return new element_value_annotation(ANNOTATION, annotation::read(input, pool), pool);
+	case ARRAY: // Array
+		input.read_be(index);
+		for (int i = 0; i < index; i++)
+		{
+			vals.push_back(element_value::readElementValue(input, pool));
+		}
+		return new element_value_array(ARRAY, vals, pool);
+	default:
+		throw new java::classfile_exception();
+	}
+}
+}
\ No newline at end of file
diff --git a/libraries/classparser/src/annotations.h b/libraries/classparser/src/annotations.h
new file mode 100644
index 00000000..aa25d241
--- /dev/null
+++ b/libraries/classparser/src/annotations.h
@@ -0,0 +1,277 @@
+#pragma once
+#include "classfile.h"
+#include <map>
+#include <vector>
+
+namespace java
+{
+enum element_value_type : uint8_t
+{
+	INVALID = 0,
+	STRING = 's',
+	ENUM_CONSTANT = 'e',
+	CLASS = 'c',
+	ANNOTATION = '@',
+	ARRAY = '[',			// one array dimension
+	PRIMITIVE_INT = 'I',	// integer
+	PRIMITIVE_BYTE = 'B',   // signed byte
+	PRIMITIVE_CHAR = 'C',   // Unicode character code point in the Basic Multilingual Plane,
+							// encoded with UTF-16
+	PRIMITIVE_DOUBLE = 'D', // double-precision floating-point value
+	PRIMITIVE_FLOAT = 'F',  // single-precision floating-point value
+	PRIMITIVE_LONG = 'J',   // long integer
+	PRIMITIVE_SHORT = 'S',  // signed short
+	PRIMITIVE_BOOLEAN = 'Z' // true or false
+};
+/**
+ * The element_value structure is a discriminated union representing the value of an
+ *element-value pair.
+ * It is used to represent element values in all attributes that describe annotations
+ * - RuntimeVisibleAnnotations
+ * - RuntimeInvisibleAnnotations
+ * - RuntimeVisibleParameterAnnotations
+ * - RuntimeInvisibleParameterAnnotations).
+ *
+ * The element_value structure has the following format:
+ */
+class element_value
+{
+protected:
+	element_value_type type;
+	constant_pool &pool;
+
+public:
+	element_value(element_value_type type, constant_pool &pool) : type(type), pool(pool) {};
+
+	element_value_type getElementValueType()
+	{
+		return type;
+	}
+
+	virtual std::string toString() = 0;
+
+	static element_value *readElementValue(util::membuffer &input, constant_pool &pool);
+};
+
+/**
+ * Each value of the annotations table represents a single runtime-visible annotation on a
+ * program element.
+ * The annotation structure has the following format:
+ */
+class annotation
+{
+public:
+	typedef std::vector<std::pair<uint16_t, element_value *>> value_list;
+
+protected:
+	/**
+	 * The value of the type_index item must be a valid index into the constant_pool table.
+	 * The constant_pool entry at that index must be a CONSTANT_Utf8_info (§4.4.7) structure
+	 * representing a field descriptor representing the annotation type corresponding
+	 * to the annotation represented by this annotation structure.
+	 */
+	uint16_t type_index;
+	/**
+	 * map between element_name_index and value.
+	 *
+	 * The value of the element_name_index item must be a valid index into the constant_pool
+	 *table.
+	 * The constant_pool entry at that index must be a CONSTANT_Utf8_info (§4.4.7) structure
+	 *representing
+	 * a valid field descriptor (§4.3.2) that denotes the name of the annotation type element
+	 *represented
+	 * by this element_value_pairs entry.
+	 */
+	value_list name_val_pairs;
+	/**
+	 * Reference to the parent constant pool
+	 */
+	constant_pool &pool;
+
+public:
+	annotation(uint16_t type_index, constant_pool &pool)
+		: type_index(type_index), pool(pool) {};
+	~annotation()
+	{
+		for (unsigned i = 0; i < name_val_pairs.size(); i++)
+		{
+			delete name_val_pairs[i].second;
+		}
+	}
+	void add_pair(uint16_t key, element_value *value)
+	{
+		name_val_pairs.push_back(std::make_pair(key, value));
+	}
+	;
+	value_list::const_iterator begin()
+	{
+		return name_val_pairs.cbegin();
+	}
+	value_list::const_iterator end()
+	{
+		return name_val_pairs.cend();
+	}
+	std::string toString();
+	static annotation *read(util::membuffer &input, constant_pool &pool);
+};
+typedef std::vector<annotation *> annotation_table;
+
+/// type for simple value annotation elements
+class element_value_simple : public element_value
+{
+protected:
+	/// index of the constant in the constant pool
+	uint16_t index;
+
+public:
+	element_value_simple(element_value_type type, uint16_t index, constant_pool &pool)
+		: element_value(type, pool), index(index) {
+										 // TODO: verify consistency
+									 };
+	uint16_t getIndex()
+	{
+		return index;
+	}
+	virtual std::string toString()
+	{
+		return pool[index].toString();
+	}
+	;
+};
+/// The enum_const_value item is used if the tag item is 'e'.
+class element_value_enum : public element_value
+{
+protected:
+	/**
+	 * The value of the type_name_index item must be a valid index into the constant_pool table.
+	 * The constant_pool entry at that index must be a CONSTANT_Utf8_info (§4.4.7) structure
+	 * representing a valid field descriptor (§4.3.2) that denotes the internal form of the
+	 * binary
+	 * name (§4.2.1) of the type of the enum constant represented by this element_value
+	 * structure.
+	 */
+	uint16_t typeIndex;
+	/**
+	 * The value of the const_name_index item must be a valid index into the constant_pool
+	 * table.
+	 * The constant_pool entry at that index must be a CONSTANT_Utf8_info (§4.4.7) structure
+	 * representing the simple name of the enum constant represented by this element_value
+	 * structure.
+	 */
+	uint16_t valueIndex;
+
+public:
+	element_value_enum(element_value_type type, uint16_t typeIndex, uint16_t valueIndex,
+					   constant_pool &pool)
+		: element_value(type, pool), typeIndex(typeIndex), valueIndex(valueIndex)
+	{
+		// TODO: verify consistency
+	}
+	uint16_t getValueIndex()
+	{
+		return valueIndex;
+	}
+	uint16_t getTypeIndex()
+	{
+		return typeIndex;
+	}
+	virtual std::string toString()
+	{
+		return "enum value";
+	}
+	;
+};
+
+class element_value_class : public element_value
+{
+protected:
+	/**
+	 * The class_info_index item must be a valid index into the constant_pool table.
+	 * The constant_pool entry at that index must be a CONSTANT_Utf8_info (§4.4.7) structure
+	 * representing the return descriptor (§4.3.3) of the type that is reified by the class
+	 * represented by this element_value structure.
+	 *
+	 * For example, 'V' for Void.class, 'Ljava/lang/Object;' for Object, etc.
+	 *
+	 * Or in plain english, you can store type information in annotations. Yay.
+	 */
+	uint16_t classIndex;
+
+public:
+	element_value_class(element_value_type type, uint16_t classIndex, constant_pool &pool)
+		: element_value(type, pool), classIndex(classIndex)
+	{
+		// TODO: verify consistency
+	}
+	uint16_t getIndex()
+	{
+		return classIndex;
+	}
+	virtual std::string toString()
+	{
+		return "class";
+	}
+	;
+};
+
+/// nested annotations... yay
+class element_value_annotation : public element_value
+{
+private:
+	annotation *nestedAnnotation;
+
+public:
+	element_value_annotation(element_value_type type, annotation *nestedAnnotation,
+							 constant_pool &pool)
+		: element_value(type, pool), nestedAnnotation(nestedAnnotation) {};
+	~element_value_annotation()
+	{
+		if (nestedAnnotation)
+		{
+			delete nestedAnnotation;
+			nestedAnnotation = nullptr;
+		}
+	}
+	virtual std::string toString()
+	{
+		return "nested annotation";
+	}
+	;
+};
+
+/// and arrays!
+class element_value_array : public element_value
+{
+public:
+	typedef std::vector<element_value *> elem_vec;
+
+protected:
+	elem_vec values;
+
+public:
+	element_value_array(element_value_type type, std::vector<element_value *> &values,
+						constant_pool &pool)
+		: element_value(type, pool), values(values) {};
+	~element_value_array()
+	{
+		for (unsigned i = 0; i < values.size(); i++)
+		{
+			delete values[i];
+		}
+	}
+	;
+	elem_vec::const_iterator begin()
+	{
+		return values.cbegin();
+	}
+	elem_vec::const_iterator end()
+	{
+		return values.cend();
+	}
+	virtual std::string toString()
+	{
+		return "array";
+	}
+	;
+};
+}
\ No newline at end of file
diff --git a/libraries/classparser/src/classfile.h b/libraries/classparser/src/classfile.h
new file mode 100644
index 00000000..a5e7ee50
--- /dev/null
+++ b/libraries/classparser/src/classfile.h
@@ -0,0 +1,156 @@
+#pragma once
+#include "membuffer.h"
+#include "constants.h"
+#include "annotations.h"
+#include <map>
+namespace java
+{
+/**
+ * Class representing a Java .class file
+ */
+class classfile : public util::membuffer
+{
+public:
+	classfile(char *data, std::size_t size) : membuffer(data, size)
+	{
+		valid = false;
+		is_synthetic = false;
+		read_be(magic);
+		if (magic != 0xCAFEBABE)
+			throw new classfile_exception();
+		read_be(minor_version);
+		read_be(major_version);
+		constants.load(*this);
+		read_be(access_flags);
+		read_be(this_class);
+		read_be(super_class);
+
+		// Interfaces
+		uint16_t iface_count = 0;
+		read_be(iface_count);
+		while (iface_count)
+		{
+			uint16_t iface;
+			read_be(iface);
+			interfaces.push_back(iface);
+			iface_count--;
+		}
+
+		// Fields
+		// read fields (and attributes from inside fields) (and possible inner classes. yay for
+		// recursion!)
+		// for now though, we will ignore all attributes
+		/*
+		 * field_info
+		 * {
+		 * 	u2 access_flags;
+		 * 	u2 name_index;
+		 * 	u2 descriptor_index;
+		 * 	u2 attributes_count;
+		 * 	attribute_info attributes[attributes_count];
+		 * }
+		 */
+		uint16_t field_count = 0;
+		read_be(field_count);
+		while (field_count)
+		{
+			// skip field stuff
+			skip(6);
+			// and skip field attributes
+			uint16_t attr_count = 0;
+			read_be(attr_count);
+			while (attr_count)
+			{
+				skip(2);
+				uint32_t attr_length = 0;
+				read_be(attr_length);
+				skip(attr_length);
+				attr_count--;
+			}
+			field_count--;
+		}
+
+		// class methods
+		/*
+		 * method_info
+		 * {
+		 * 	u2 access_flags;
+		 * 	u2 name_index;
+		 * 	u2 descriptor_index;
+		 * 	u2 attributes_count;
+		 * 	attribute_info attributes[attributes_count];
+		 * }
+		 */
+		uint16_t method_count = 0;
+		read_be(method_count);
+		while (method_count)
+		{
+			skip(6);
+			// and skip method attributes
+			uint16_t attr_count = 0;
+			read_be(attr_count);
+			while (attr_count)
+			{
+				skip(2);
+				uint32_t attr_length = 0;
+				read_be(attr_length);
+				skip(attr_length);
+				attr_count--;
+			}
+			method_count--;
+		}
+
+		// class attributes
+		// there are many kinds of attributes. this is just the generic wrapper structure.
+		// type is decided by attribute name. extensions to the standard are *possible*
+		// class annotations are one kind of a attribute (one per class)
+		/*
+		 * attribute_info
+		 * {
+		 * 	u2 attribute_name_index;
+		 * 	u4 attribute_length;
+		 * 	u1 info[attribute_length];
+		 * }
+		 */
+		uint16_t class_attr_count = 0;
+		read_be(class_attr_count);
+		while (class_attr_count)
+		{
+			uint16_t name_idx = 0;
+			read_be(name_idx);
+			uint32_t attr_length = 0;
+			read_be(attr_length);
+
+			auto name = constants[name_idx];
+			if (name.str_data == "RuntimeVisibleAnnotations")
+			{
+				uint16_t num_annotations = 0;
+				read_be(num_annotations);
+				while (num_annotations)
+				{
+					visible_class_annotations.push_back(annotation::read(*this, constants));
+					num_annotations--;
+				}
+			}
+			else
+				skip(attr_length);
+			class_attr_count--;
+		}
+		valid = true;
+	}
+	;
+	bool valid;
+	bool is_synthetic;
+	uint32_t magic;
+	uint16_t minor_version;
+	uint16_t major_version;
+	constant_pool constants;
+	uint16_t access_flags;
+	uint16_t this_class;
+	uint16_t super_class;
+	// interfaces this class implements ? must be. investigate.
+	std::vector<uint16_t> interfaces;
+	// FIXME: doesn't free up memory on delete
+	java::annotation_table visible_class_annotations;
+};
+}
\ No newline at end of file
diff --git a/libraries/classparser/src/constants.h b/libraries/classparser/src/constants.h
new file mode 100644
index 00000000..242b943e
--- /dev/null
+++ b/libraries/classparser/src/constants.h
@@ -0,0 +1,220 @@
+#pragma once
+#include "errors.h"
+#include <sstream>
+
+namespace java
+{
+class constant
+{
+public:
+	enum type_t : uint8_t
+	{
+		j_hole = 0, // HACK: this is a hole in the array, because java is crazy
+		j_string_data = 1,
+		j_int = 3,
+		j_float = 4,
+		j_long = 5,
+		j_double = 6,
+		j_class = 7,
+		j_string = 8,
+		j_fieldref = 9,
+		j_methodref = 10,
+		j_interface_methodref = 11,
+		j_nameandtype = 12
+	} type;
+
+	constant(util::membuffer &buf)
+	{
+		buf.read(type);
+		// invalid constant type!
+		if (type > j_nameandtype || type == (type_t)0 || type == (type_t)2)
+			throw new classfile_exception();
+
+		// load data depending on type
+		switch (type)
+		{
+		case j_float:
+		case j_int:
+			buf.read_be(int_data); // same as float data really
+			break;
+		case j_double:
+		case j_long:
+			buf.read_be(long_data); // same as double
+			break;
+		case j_class:
+			buf.read_be(ref_type.class_idx);
+			break;
+		case j_fieldref:
+		case j_methodref:
+		case j_interface_methodref:
+			buf.read_be(ref_type.class_idx);
+			buf.read_be(ref_type.name_and_type_idx);
+			break;
+		case j_string:
+			buf.read_be(index);
+			break;
+		case j_string_data:
+			// HACK HACK: for now, we call these UTF-8 and do no further processing.
+			// Later, we should do some decoding. It's really modified UTF-8
+			// * U+0000 is represented as 0xC0,0x80 invalid character
+			// * any single zero byte ends the string
+			// * characters above U+10000 are encoded like in CESU-8
+			buf.read_jstr(str_data);
+			break;
+		case j_nameandtype:
+			buf.read_be(name_and_type.name_index);
+			buf.read_be(name_and_type.descriptor_index);
+			break;
+		}
+	}
+
+	constant(int fake)
+	{
+		type = j_hole;
+	}
+
+	std::string toString()
+	{
+		std::ostringstream ss;
+		switch (type)
+		{
+		case j_hole:
+			ss << "Fake legacy entry";
+			break;
+		case j_float:
+			ss << "Float: " << float_data;
+			break;
+		case j_double:
+			ss << "Double: " << double_data;
+			break;
+		case j_int:
+			ss << "Int: " << int_data;
+			break;
+		case j_long:
+			ss << "Long: " << long_data;
+			break;
+		case j_string_data:
+			ss << "StrData: " << str_data;
+			break;
+		case j_string:
+			ss << "Str: " << index;
+			break;
+		case j_fieldref:
+			ss << "FieldRef: " << ref_type.class_idx << " " << ref_type.name_and_type_idx;
+			break;
+		case j_methodref:
+			ss << "MethodRef: " << ref_type.class_idx << " " << ref_type.name_and_type_idx;
+			break;
+		case j_interface_methodref:
+			ss << "IfMethodRef: " << ref_type.class_idx << " " << ref_type.name_and_type_idx;
+			break;
+		case j_class:
+			ss << "Class: " << ref_type.class_idx;
+			break;
+		case j_nameandtype:
+			ss << "NameAndType: " << name_and_type.name_index << " "
+			   << name_and_type.descriptor_index;
+			break;
+		}
+		return ss.str();
+	}
+
+	std::string str_data; /** String data in 'modified utf-8'.*/
+	// store everything here.
+	union
+	{
+		int32_t int_data;
+		int64_t long_data;
+		float float_data;
+		double double_data;
+		uint16_t index;
+		struct
+		{
+			/**
+			 * Class reference:
+			 *   an index within the constant pool to a UTF-8 string containing
+			 *   the fully qualified class name (in internal format)
+			 * Used for j_class, j_fieldref, j_methodref and j_interface_methodref
+			 */
+			uint16_t class_idx;
+			// used for j_fieldref, j_methodref and j_interface_methodref
+			uint16_t name_and_type_idx;
+		} ref_type;
+		struct
+		{
+			uint16_t name_index;
+			uint16_t descriptor_index;
+		} name_and_type;
+	};
+};
+
+/**
+ * A helper class that represents the custom container used in Java class file for storage of
+ * constants
+ */
+class constant_pool
+{
+public:
+	/**
+	 * Create a pool of constants
+	 */
+	constant_pool()
+	{
+	}
+	/**
+	 * Load a java constant pool
+	 */
+	void load(util::membuffer &buf)
+	{
+		uint16_t length = 0;
+		buf.read_be(length);
+		length--;
+		uint16_t index = 1;
+		const constant *last_constant = nullptr;
+		while (length)
+		{
+			const constant &cnst = constant(buf);
+			constants.push_back(cnst);
+			last_constant = &constants[constants.size() - 1];
+			if (last_constant->type == constant::j_double ||
+				last_constant->type == constant::j_long)
+			{
+				// push in a fake constant to preserve indexing
+				constants.push_back(constant(0));
+				length -= 2;
+				index += 2;
+			}
+			else
+			{
+				length--;
+				index++;
+			}
+		}
+	}
+	typedef std::vector<java::constant> container_type;
+	/**
+	 * Access constants based on jar file index numbers (index of the first element is 1)
+	 */
+	java::constant &operator[](std::size_t constant_index)
+	{
+		if (constant_index == 0 || constant_index > constants.size())
+		{
+			throw new classfile_exception();
+		}
+		return constants[constant_index - 1];
+	}
+	;
+	container_type::const_iterator begin() const
+	{
+		return constants.begin();
+	}
+	;
+	container_type::const_iterator end() const
+	{
+		return constants.end();
+	}
+
+private:
+	container_type constants;
+};
+}
diff --git a/libraries/classparser/src/errors.h b/libraries/classparser/src/errors.h
new file mode 100644
index 00000000..ddbbd828
--- /dev/null
+++ b/libraries/classparser/src/errors.h
@@ -0,0 +1,8 @@
+#pragma once
+#include <exception>
+namespace java
+{
+class classfile_exception : public std::exception
+{
+};
+}
diff --git a/libraries/classparser/src/javaendian.h b/libraries/classparser/src/javaendian.h
new file mode 100644
index 00000000..d488b382
--- /dev/null
+++ b/libraries/classparser/src/javaendian.h
@@ -0,0 +1,76 @@
+#pragma once
+#include <stdint.h>
+
+/**
+ * Swap bytes between big endian and local number representation
+ */
+namespace util
+{
+#ifdef MULTIMC_BIG_ENDIAN
+inline uint64_t bigswap(uint64_t x)
+{
+	return x;
+}
+;
+inline uint32_t bigswap(uint32_t x)
+{
+	return x;
+}
+;
+inline uint16_t bigswap(uint16_t x)
+{
+	return x;
+}
+;
+inline int64_t bigswap(int64_t x)
+{
+	return x;
+}
+;
+inline int32_t bigswap(int32_t x)
+{
+	return x;
+}
+;
+inline int16_t bigswap(int16_t x)
+{
+	return x;
+}
+;
+#else
+inline uint64_t bigswap(uint64_t x)
+{
+	return (x >> 56) | ((x << 40) & 0x00FF000000000000) | ((x << 24) & 0x0000FF0000000000) |
+		   ((x << 8) & 0x000000FF00000000) | ((x >> 8) & 0x00000000FF000000) |
+		   ((x >> 24) & 0x0000000000FF0000) | ((x >> 40) & 0x000000000000FF00) | (x << 56);
+}
+;
+inline uint32_t bigswap(uint32_t x)
+{
+	return (x >> 24) | ((x << 8) & 0x00FF0000) | ((x >> 8) & 0x0000FF00) | (x << 24);
+}
+;
+inline uint16_t bigswap(uint16_t x)
+{
+	return (x >> 8) | (x << 8);
+}
+;
+inline int64_t bigswap(int64_t x)
+{
+	return (x >> 56) | ((x << 40) & 0x00FF000000000000) | ((x << 24) & 0x0000FF0000000000) |
+		   ((x << 8) & 0x000000FF00000000) | ((x >> 8) & 0x00000000FF000000) |
+		   ((x >> 24) & 0x0000000000FF0000) | ((x >> 40) & 0x000000000000FF00) | (x << 56);
+}
+;
+inline int32_t bigswap(int32_t x)
+{
+	return (x >> 24) | ((x << 8) & 0x00FF0000) | ((x >> 8) & 0x0000FF00) | (x << 24);
+}
+;
+inline int16_t bigswap(int16_t x)
+{
+	return (x >> 8) | (x << 8);
+}
+;
+#endif
+}
diff --git a/libraries/classparser/src/javautils.cpp b/libraries/classparser/src/javautils.cpp
new file mode 100644
index 00000000..f9310e5f
--- /dev/null
+++ b/libraries/classparser/src/javautils.cpp
@@ -0,0 +1,83 @@
+/* Copyright 2013-2015 MultiMC Contributors
+ *
+ * Authors: Orochimarufan <orochimarufan.x3@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "classfile.h"
+#include "javautils.h"
+
+#include <QFile>
+#include <quazipfile.h>
+
+namespace javautils
+{
+
+QString GetMinecraftJarVersion(QString jarName)
+{
+	QString version = MCVer_Unknown;
+
+	// check if minecraft.jar exists
+	QFile jar(jarName);
+	if (!jar.exists())
+		return version;
+
+	// open minecraft.jar
+	QuaZip zip(&jar);
+	if (!zip.open(QuaZip::mdUnzip))
+		return version;
+
+	// open Minecraft.class
+	zip.setCurrentFile("net/minecraft/client/Minecraft.class", QuaZip::csSensitive);
+	QuaZipFile Minecraft(&zip);
+	if (!Minecraft.open(QuaZipFile::ReadOnly))
+		return version;
+
+	// read Minecraft.class
+	qint64 size = Minecraft.size();
+	char *classfile = new char[size];
+	Minecraft.read(classfile, size);
+
+	// parse Minecraft.class
+	try
+	{
+		char *temp = classfile;
+		java::classfile MinecraftClass(temp, size);
+		java::constant_pool constants = MinecraftClass.constants;
+		for (java::constant_pool::container_type::const_iterator iter = constants.begin();
+			 iter != constants.end(); iter++)
+		{
+			const java::constant &constant = *iter;
+			if (constant.type != java::constant::j_string_data)
+				continue;
+			const std::string &str = constant.str_data;
+			if (str.compare(0, 20, "Minecraft Minecraft ") == 0)
+			{
+				version = str.substr(20).data();
+				break;
+			}
+		}
+	}
+	catch (java::classfile_exception &)
+	{
+	}
+
+	// clean up
+	delete[] classfile;
+	Minecraft.close();
+	zip.close();
+	jar.close();
+
+	return version;
+}
+}
diff --git a/libraries/classparser/src/membuffer.h b/libraries/classparser/src/membuffer.h
new file mode 100644
index 00000000..ab83412a
--- /dev/null
+++ b/libraries/classparser/src/membuffer.h
@@ -0,0 +1,63 @@
+#pragma once
+#include <stdint.h>
+#include <string>
+#include <vector>
+#include <exception>
+#include "javaendian.h"
+
+namespace util
+{
+class membuffer
+{
+public:
+	membuffer(char *buffer, std::size_t size)
+	{
+		current = start = buffer;
+		end = start + size;
+	}
+	~membuffer()
+	{
+		// maybe? possibly? left out to avoid confusion. for now.
+		// delete start;
+	}
+	/**
+		* Read some value. That's all ;)
+		*/
+	template <class T> void read(T &val)
+	{
+		val = *(T *)current;
+		current += sizeof(T);
+	}
+	/**
+		* Read a big-endian number
+		* valid for 2-byte, 4-byte and 8-byte variables
+		*/
+	template <class T> void read_be(T &val)
+	{
+		val = util::bigswap(*(T *)current);
+		current += sizeof(T);
+	}
+	/**
+		* Read a string in the format:
+		* 2B length (big endian, unsigned)
+		* length bytes data
+		*/
+	void read_jstr(std::string &str)
+	{
+		uint16_t length = 0;
+		read_be(length);
+		str.append(current, length);
+		current += length;
+	}
+	/**
+		* Skip N bytes
+		*/
+	void skip(std::size_t N)
+	{
+		current += N;
+	}
+
+private:
+	char *start, *end, *current;
+};
+}