jdk/src/java.base/share/native/libjimage/imageDecompressor.hpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */

 #ifndef LIBJIMAGE_IMAGEDECOMPRESSOR_HPP
 #define LIBJIMAGE_IMAGEDECOMPRESSOR_HPP

 #include <assert.h>
 #include <string.h>

 #include "imageFile.hpp"
 #include "inttypes.hpp"
 #include "jni.h"

 /*
  * Compressed resources located in image have an header.
  * This header contains:
  * - _magic: A magic u4, required to retrieved the header in the compressed content
  * - _size: The size of the compressed resource.
  * - _uncompressed_size: The uncompressed size of the compressed resource.
  * - _decompressor_name_offset: The ImageDecompressor instance name StringsTable offset.
  * - _decompressor_config_offset: StringsTable offset of configuration that could be needed by
  *   the decompressor in order to decompress.
  * - _is_terminal: 1: the compressed content is terminal. Uncompressing it would
  *   create the actual resource. 0: the compressed content is not terminal. Uncompressing it
  *   will result in a compressed content to be decompressed (This occurs when a stack of compressors
  *   have been used to compress the resource.
  */
 struct ResourceHeader {
   /* Length of header, needed to retrieve content offset */
   static const u1 resource_header_length = 21;
   /* magic bytes that identifies a compressed resource header*/
   static const u4 resource_header_magic = 0xCAFEFAFA;
   u4 _magic; // Resource header
   u4 _size;  // Resource size
   u4 _uncompressed_size;  // Expected uncompressed size
   u4 _decompressor_name_offset;  // Strings table decompressor offset
   u4 _decompressor_config_offset; // Strings table config offset
   u1 _is_terminal; // Last decompressor 1, otherwise 0.
 };

 /*
  * Resources located in jimage file can be compressed. Compression occurs at
  * jimage file creation time. When compressed a resource is added an header that
  * contains the name of the compressor that compressed it.
  * Various compression strategies can be applied to compress a resource.
  * The same resource can even be compressed multiple time by a stack of compressors.
  * At runtime, a resource is decompressed in a loop until there is no more header
  * meaning that the resource is equivalent to the not compressed resource.
  * In each iteration, the name of the compressor located in the current header
  * is used to retrieve the associated instance of ImageDecompressor.
  * For example “zip” is the name of the compressor that compresses resources
  * using the zip algorithm. The ZipDecompressor class name is also “zip”.
  * ImageDecompressor instances are retrieved from a static array in which
  * they are registered.
  */
 class ImageDecompressor {

 private:
   const char* _name;

   /*
    * Array of concrete decompressors. This array is used to retrieve the decompressor
    * that can handle resource decompression.
    */
   static ImageDecompressor** _decompressors;
   /**
    * Num of decompressors
    */
   static int _decompressors_num;
   /*
    * Identifier of a decompressor. This name is the identification key to retrieve
    * decompressor from a resource header.
    */
   inline const char* get_name() const { return _name; }


 protected:
   ImageDecompressor(const char* name) : _name(name) {
   }
   virtual void decompress_resource(u1* data, u1* uncompressed,
     ResourceHeader* header, const ImageStrings* strings) = 0;

 public:
   static void image_decompressor_init();
   static void image_decompressor_close();
   static ImageDecompressor* get_decompressor(const char * decompressor_name) ;
   static void decompress_resource(u1* compressed, u1* uncompressed,
     u4 uncompressed_size, const ImageStrings* strings);
 };

 /**
  * Zip decompressor.
  */
 class ZipDecompressor : public ImageDecompressor {
 public:
   ZipDecompressor(const char* sym) : ImageDecompressor(sym) { }
   void decompress_resource(u1* data, u1* uncompressed, ResourceHeader* header,
     const ImageStrings* strings);
   static jboolean decompress(void *in, u8 inSize, void *out, u8 outSize, char **pmsg);
 };

 /*
  * Shared Strings decompressor. This decompressor reconstruct the class
  * constant pool UTF_U entries by retrieving strings stored in jimage strings table.
  * In addition, if the UTF_8 entry is a descriptor, the descriptor has to be rebuilt,
  * all java type having been removed from the descriptor and added to the sting table.
  * eg: "(Ljava/lang/String;I)V" ==> "(L;I)V" and "java/lang", "String"
  * stored in string table. offsets to the 2 strings are compressed and stored in the
  * constantpool entry.
  */
 class SharedStringDecompressor : public ImageDecompressor {
 private:
   // the constant pool tag for UTF8 string located in strings table
   static const int externalized_string = 23;
   // the constant pool tag for UTF8 descriptors string located in strings table
   static const int externalized_string_descriptor = 25;
   // the constant pool tag for UTF8
   static const int constant_utf8 = 1;
   // the constant pool tag for long
   static const int constant_long = 5;
   // the constant pool tag for double
   static const int constant_double = 6;
   // array index is the constant pool tag. value is size.
   // eg: array[5]  = 8; means size of long is 8 bytes.
   static const u1 sizes[];
   // bit 5 and 6 are used to store the length of the compressed integer.
   // size can be 1 (01), 2 (10), 3 (11).
   // 0x60 ==> 0110000
   static const int compressed_index_size_mask = 0x60;
   /*
    * mask the length bits (5 and 6) and move to the right 5 bits.
    */
   inline static int get_compressed_length(char c) { return ((char) (c & compressed_index_size_mask) >> 5); }
   inline static bool is_compressed(signed char b1) { return b1 < 0; }
   static int decompress_int(unsigned char*& value);
 public:
   SharedStringDecompressor(const char* sym) : ImageDecompressor(sym){}
   void decompress_resource(u1* data, u1* uncompressed, ResourceHeader* header,
   const ImageStrings* strings);
 };
 #endif // LIBJIMAGE_IMAGEDECOMPRESSOR_HPP
	/*
	* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*
	*/

	#ifndef LIBJIMAGE_IMAGEDECOMPRESSOR_HPP
	#define LIBJIMAGE_IMAGEDECOMPRESSOR_HPP

	#include <assert.h>
	#include <string.h>

	#include "imageFile.hpp"
	#include "inttypes.hpp"
	#include "jni.h"

	/*
	* Compressed resources located in image have an header.
	* This header contains:
	* - _magic: A magic u4, required to retrieved the header in the compressed content
	* - _size: The size of the compressed resource.
	* - _uncompressed_size: The uncompressed size of the compressed resource.
	* - _decompressor_name_offset: The ImageDecompressor instance name StringsTable offset.
	* - _decompressor_config_offset: StringsTable offset of configuration that could be needed by
	* the decompressor in order to decompress.
	* - _is_terminal: 1: the compressed content is terminal. Uncompressing it would
	* create the actual resource. 0: the compressed content is not terminal. Uncompressing it
	* will result in a compressed content to be decompressed (This occurs when a stack of compressors
	* have been used to compress the resource.
	*/
	struct ResourceHeader {
	/* Length of header, needed to retrieve content offset */
	static const u1 resource_header_length = 21;
	/* magic bytes that identifies a compressed resource header*/
	static const u4 resource_header_magic = 0xCAFEFAFA;
	u4 _magic; // Resource header
	u4 _size; // Resource size
	u4 _uncompressed_size; // Expected uncompressed size
	u4 _decompressor_name_offset; // Strings table decompressor offset
	u4 _decompressor_config_offset; // Strings table config offset
	u1 _is_terminal; // Last decompressor 1, otherwise 0.
	};

	/*
	* Resources located in jimage file can be compressed. Compression occurs at
	* jimage file creation time. When compressed a resource is added an header that
	* contains the name of the compressor that compressed it.
	* Various compression strategies can be applied to compress a resource.
	* The same resource can even be compressed multiple time by a stack of compressors.
	* At runtime, a resource is decompressed in a loop until there is no more header
	* meaning that the resource is equivalent to the not compressed resource.
	* In each iteration, the name of the compressor located in the current header
	* is used to retrieve the associated instance of ImageDecompressor.
	* For example “zip” is the name of the compressor that compresses resources
	* using the zip algorithm. The ZipDecompressor class name is also “zip”.
	* ImageDecompressor instances are retrieved from a static array in which
	* they are registered.
	*/
	class ImageDecompressor {

	private:
	const char* _name;

	/*
	* Array of concrete decompressors. This array is used to retrieve the decompressor
	* that can handle resource decompression.
	*/
	static ImageDecompressor** _decompressors;
	/**
	* Num of decompressors
	*/
	static int _decompressors_num;
	/*
	* Identifier of a decompressor. This name is the identification key to retrieve
	* decompressor from a resource header.
	*/
	inline const char* get_name() const { return _name; }


	protected:
	ImageDecompressor(const char* name) : _name(name) {
	}
	virtual void decompress_resource(u1* data, u1* uncompressed,
	ResourceHeader* header, const ImageStrings* strings) = 0;

	public:
	static void image_decompressor_init();
	static void image_decompressor_close();
	static ImageDecompressor* get_decompressor(const char * decompressor_name) ;
	static void decompress_resource(u1* compressed, u1* uncompressed,
	u4 uncompressed_size, const ImageStrings* strings);
	};

	/**
	* Zip decompressor.
	*/
	class ZipDecompressor : public ImageDecompressor {
	public:
	ZipDecompressor(const char* sym) : ImageDecompressor(sym) { }
	void decompress_resource(u1* data, u1* uncompressed, ResourceHeader* header,
	const ImageStrings* strings);
	static jboolean decompress(void in, u8 inSize, void out, u8 outSize, char **pmsg);
	};

	/*
	* Shared Strings decompressor. This decompressor reconstruct the class
	* constant pool UTF_U entries by retrieving strings stored in jimage strings table.
	* In addition, if the UTF_8 entry is a descriptor, the descriptor has to be rebuilt,
	* all java type having been removed from the descriptor and added to the sting table.
	* eg: "(Ljava/lang/String;I)V" ==> "(L;I)V" and "java/lang", "String"
	* stored in string table. offsets to the 2 strings are compressed and stored in the
	* constantpool entry.
	*/
	class SharedStringDecompressor : public ImageDecompressor {
	private:
	// the constant pool tag for UTF8 string located in strings table
	static const int externalized_string = 23;
	// the constant pool tag for UTF8 descriptors string located in strings table
	static const int externalized_string_descriptor = 25;
	// the constant pool tag for UTF8
	static const int constant_utf8 = 1;
	// the constant pool tag for long
	static const int constant_long = 5;
	// the constant pool tag for double
	static const int constant_double = 6;
	// array index is the constant pool tag. value is size.
	// eg: array[5] = 8; means size of long is 8 bytes.
	static const u1 sizes[];
	// bit 5 and 6 are used to store the length of the compressed integer.
	// size can be 1 (01), 2 (10), 3 (11).
	// 0x60 ==> 0110000
	static const int compressed_index_size_mask = 0x60;
	/*
	* mask the length bits (5 and 6) and move to the right 5 bits.
	*/
	inline static int get_compressed_length(char c) { return ((char) (c & compressed_index_size_mask) >> 5); }
	inline static bool is_compressed(signed char b1) { return b1 < 0; }
	static int decompress_int(unsigned char*& value);
	public:
	SharedStringDecompressor(const char* sym) : ImageDecompressor(sym){}
	void decompress_resource(u1* data, u1* uncompressed, ResourceHeader* header,
	const ImageStrings* strings);
	};
	#endif // LIBJIMAGE_IMAGEDECOMPRESSOR_HPP