Method for analyzing Classref constant of CAP file

A constant and file technology, which is applied in the field of smart cards, can solve the problems of time-consuming and time-consuming write operations, and achieve the effect of saving time, saving time, and saving time for calculating relative offsets

Active Publication Date: 2014-03-26
BEIJING CEC HUADA ELECTRONIC DESIGN CO LTD
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Problems solved by technology

[0020] The solution provided by SUN has the following defects: because this solution will involve multiple read and write operations to the memory when parsing the exported components during the process of downloading the package, and the write operation is in the field of smart cards that require high speed. It is extremely time-consuming, so this solution will cause time-consuming increase in the download process

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  • Method for analyzing Classref constant of CAP file
  • Method for analyzing Classref constant of CAP file
  • Method for analyzing Classref constant of CAP file

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Embodiment Construction

[0034] The parsing method of the CONSTANT_Classref constant of the CAP file constant pool component provided by the present invention will be described in more detail below in conjunction with the drawings and embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0035] The parsing method of the CAP file constant pool component CONSTANT_Classref constant provided in the embodiment of the present invention, such as Figure 4 As shown, the method steps include:

[0036] S101, analyzing the exported components and constant pool components of the JCRE system package;

[0037] S102, analyzing the export component and the constant pool component in the download package;

[0038] S103. Process relevant bytecode instructions during interpretation and execution.

[0039] In the embodiment of the present invention,...

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Abstract

The invention discloses a method for analyzing a CONSTANT_Classref constant of a CAP file pool assembly. The method includes retaining an original value of the class_offset in the class_export_info of a leading out assembly of a JCRE system package and a downloading package; if the CONSTANT_Classref constant in the constant pool assembly is of a category other than the package, finding a package index of the package through a package_token item, storing the package index to replace the package_token item, enabling the highest position of the package index to be 1, retaining the value of the class_token item, replacing a constant pool index in a byte code operand with the value of the analyzed constant during reference position assembly analysis, finding a leading out assembly of the package through the package index during virtual machine explanation execution, directly reading the value of the class_offset from the corresponding class_export_info according to the class_token, and meanwhile finding a similar assembly head address of the package can be found through the package index. The absolute address of the category can be obtained through calculation according to the obtained deviation value.

Description

technical field [0001] The invention relates to the technical field of smart cards, in particular to a method for analyzing constant Classref constants in a constant pool of CAP files. Background technique [0002] JAVA card technology has successfully applied the Java language to the field of smart card technology. However, due to the resource and speed limitations of the smart card device itself, the Java language program running on it must be a specially processed program that meets the requirements of the JAVA card specification. This kind of program running on the JAVA card is called the JAVA card Applet. [0003] JAVA card technology includes three aspects: JCRE (JAVA card runtime environment), JCVM (JAVA card virtual machine) and JC API (JAVA card application programming interface). [0004] JCRE is mainly responsible for the distribution of APDU commands, channel management, and application selection. These functions are implemented in Java language, and they are JC...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F9/44
Inventor 毛云娟
Owner BEIJING CEC HUADA ELECTRONIC DESIGN CO LTD
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