Mercurial > hg > jdk9-shenandoah > jdk
view src/java.base/share/native/libjimage/imageDecompressor.hpp @ 12737:d7f0c840a572
8087181: Move native jimage code to its own library (maybe libjimage)
Reviewed-by: alanb, lfoltan, hseigel, acorn
Contributed-by: james.laskey@oracle.com, jean-francois.denise@oracle.com, roger.riggs@oracle.com
author | jlaskey |
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date | Fri, 04 Sep 2015 10:11:43 -0300 |
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/* * 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