CN1321377C - Control method of smart card storage environment - Google Patents

Abstract

The invention discloses a method for controlling a smart card storage environment. The smart card storage environment consists of a CPU, a RAM memory, a ROM memory, an EEPROM memory, a logic operation module, an encryption engine module, an interrupt processing module, a CRC generator, a random number generator, a timer device and an external interface, the RAM memory is used to store temporary data information, the ROM memory and EEPROM memory are used to store persistent data information, in the smart card, the externally input data information is first classified into storage types, and then the Different storage types control the storage rules and store them in the smart card. The control method of the smart card storage environment of the present invention effectively saves the limited computing resources and storage resources of the smart card platform, enhances the adaptability of space allocation and recycling operation, and proposes the storage management of the persistent space of the bidirectional linked list structure under the multi-application operating environment Strategy and segmented temporary space storage management strategy, design and implement the corresponding storage allocation and garbage collection.

Description

Control method of smart card storage environment

technical field

The invention relates to a method for controlling the storage environment of a smart card, in particular to a method for controlling a storage environment management system of a Java smart card.

Background technique

Java smart card technology is the transplantation of Java virtual machine technology to limited resource device platform. After compiling and converting, the Applet of the Java smart card generates a bytecode program of the virtual machine instruction set. These bytecodes are then run by the on-card virtual machine. The early operating technology of the Java virtual machine is mainly the interpretation and execution mechanism, that is, the bytecode is translated into the corresponding local execution code through the interpreter to run, and it is suitable for use in devices with fewer resources. Then, in order to improve the execution speed of bytecode, other operating technologies such as compiling to native code execution, dynamic compilation and JIT compilation and execution, HotSpot technology and direct dedicated hardware structure execution have been proposed. Although the method of compiling into local codes improves the speed significantly, it affects the security mechanism and portability of the Java language to a certain extent, which is obviously not suitable for smart card applications with high security requirements. Dynamic compilation, JIT compilation technology and HotSpot technology compile bytecode into local code at runtime, which requires a large amount of storage resources at runtime, which is not feasible in smart cards that usually only have about 2K of RAM.

At present, some smart card hardware structures are used to run bytecodes to increase the speed. The performance gain brought by this is very significant, but it also doubles the cost of the card. The dedicated hardware structure also has certain limitations, such as the expansion of pseudo-instructions, and currently there are not a large number of CPUs with a Java-specific structure in the field of smart card chips and other limited-resource devices.

The automatic garbage collection mechanism of the memory space is a major feature of the Java language, and it is also a guarantee of the security of the Java language. However, due to the slow write speed and limited read and write times of EEPROM, the implementation of garbage collection in the Java card must be different from that of the PC platform. The existing literature on storage management is only based on the Java Card 2.1 specification, and the research on temporary space management in the environment where a single Applet instance runs.

Contents of the invention

The purpose of the present invention is to provide a management method for the storage environment of the smart card, which can effectively save the limited computing resources and storage resources of the smart card platform, and enhance the adaptability of space allocation and recycling operation. The invention proposes a storage management strategy of a persistent space with a bidirectional linked list structure and a storage management strategy of a segmented temporary space under a multi-application operating environment, and designs and implements storage allocation and garbage collection management.

A control method of a smart card storage environment of the present invention, the smart card is composed of CPU, RAM memory, ROM memory, EEPROM memory, logical operation module, encryption engine module, interrupt processing module, CRC generator, random number generator, timer Constituted with an external interface, the RAM memory is used to store temporary data information, the ROM memory and EEPROM memory are used to store persistent data information, and the steps for storing externally input data information include:

(A) classify the storage type of the externally input data information to obtain the storage type,

The storage type has a first storage type, which is used to implement storage management of persistent space; and

A second storage type for storage management of the temporary space of the CLEAR_ON_RESET attribute; and

The third storage type is used to realize the storage management of the temporary space of the CLEAR_ON_DESELECT attribute;

(B) carry out storage control according to the storage rules to the storage type after (A) storage classification processing, and its first storage type is stored in the EEPROM memory; the second storage type and the third storage type are stored in the RAM memory,

The storage rules include a first storage rule, which is used to store and recycle the first storage type according to the doubly linked list structure. The storage adopts the first adaptation method, and the recycle adopts the space combination method; the second storage rule is used to store all The second storage type described above is stored from the high address end of the temporary space to the low address, and the recovery adopts the object mark recovery method; the third storage rule is used to store the third storage type from the low address of the temporary space The end starts to store to the high address, and the recovery adopts the object mark recovery method.

Advantages of the present invention: (1) The advantage of the doubly linked list structure is that a record can be easily inserted or deleted by adjusting the connection pointer, which saves the limited computing resources and storage resources of the smart card platform. At the same time, it is convenient to make the detection pointer move forward and backward, so it is easy to instantiate the object or allocate or delete the storage space of the application program. (2) The segmented temporary space storage management mechanism effectively avoids the address conflict problem in the traditional control method, and has strong self-adaptability during operation, which is very suitable for the operating environment of smart cards.

Description of drawings

Figure 1 is a schematic diagram of the internal structure of a smart card.

Fig. 2 is a flow chart of storage allocation of persistent space in the present invention.

Fig. 3 is a flow chart of the garbage collection management of the persistent space of the present invention.

Fig. 4 is a segmented temporary space storage allocation when the present invention is running.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

The invention relates to a method for controlling the storage environment of a smart card. The smart card consists of a CPU, a RAM memory, a ROM memory, an EEPROM memory, a logical operation module, an encryption engine module, an interrupt processing module, a CRC generator, a random number generator, a timer and an external The interface is formed, the RAM memory is used to store temporary data information, the ROM memory and EEPROM memory are used to store persistent data information, and the steps for storing externally input data information include:

(A) classify the storage type of the externally input data information to obtain the storage type,

The storage type has a first storage type, which is used to implement storage management of persistent space; and

A second storage type for storage management of the temporary space of the CLEAR_ON_RESET attribute; and

The third storage type is used to realize the storage management of the temporary space of the CLEAR_ON_DESELECT attribute;

(B) carry out storage control according to the storage rules to the storage type after (A) storage classification processing, and its first storage type is stored in the EEPROM memory; the second storage type and the third storage type are stored in the RAM memory,

The storage rules include a first storage rule, which is used to store and recycle the first storage type according to the doubly linked list structure. The storage adopts the first adaptation method, and the recycle adopts the space combination method; the second storage rule is used to store all The second storage type described above is stored from the high address end of the temporary space to the low address, and the recovery adopts the object mark recovery method; the third storage rule is used to store the third storage type from the low address of the temporary space The end starts to store to the high address, and the recovery adopts the object mark recovery method.

In the present invention, the persistent space storage management mechanism of the doubly linked list structure is adopted, and its doubly linked list is shown in the following table,

Doubly linked list structure

HEADERLlink(2Byte) Tag(1Byte) Size(2Byte) Rlink(2Byte) DATA FOOTERUplink(2Byte) Tag(1Byte)

In the table, the HEADER item is the head of the structure, including the following four fields: Llink: a pointer pointing to its left node, occupying 2 bytes of storage space. Tag: occupancy mark. When the tag is 1, the block is an occupied block; when the tag is 0, the block is a free block. Size: Indicates the size of the entire node, including HEADER and FOOTER. Rlink: A pointer to its right node.

The DATA item is a group of storage units with continuous addresses, which is a memory area that can be allocated to users.

The FOOTER item is the tail of the structure, including the following two fields: Uplink: a pointer pointing to the head of this node, whose value is the first address of the current node. Tag: occupancy flag, same as Tag field in HEADER.

When storing request object allocations, the first-fit method is used. Its working method is as follows: in the free linked list pointed to by the head pointer (pointing to a free block, it will search backward from this free block when the object is allocated, so the free block can be regarded as the head of the free linked list) to find the first satisfying If the size of the free block is the same as the size of the object to be allocated, this free block is allocated to the object; otherwise, it is divided into two parts, one part is allocated to the object, and the other part is unused storage area, insert it into the free list as a new free block, and modify the head pointer at the same time to make it point to the next free block of the free block found just now, so that the next time you look for a free area, it will start from the place where it ended last time Search instead of starting from scratch every time. At the same time, considering that when the free space is only a few bytes larger than the requested space, and then divide the free block at this time, there will be a large number of free blocks of several bytes in the free list, and this free block will rarely be used. Redistribution increases the external fragmentation of the storage area and reduces the utilization rate of the storage area. Therefore, here we set a difference threshold of 10 bytes. When the difference between the free space and the requested space is greater than 10 bytes, the This free block is divided; otherwise, this free block is directly allocated to the object without further division. The flow description of the allocation algorithm is shown in Figure 2.

Storage reclamation is to reclaim the storage space to be reclaimed for the given storage first address, which can be divided into the following four situations:

1) If the left block of the given block is a free block, then the given block and the left block are merged, and inserted into the free block queue as a free block instead of the left block.

2) If the right block of the given block is a free block, then the given block and the right block are combined, and inserted into the free block queue as a free block instead of the right block.

3) If the left block and the right block of the given block are both free blocks, then this block is merged with the left block and the right block, and the left block is inserted into the free block queue instead of the left block, and the right block is deleted in the free block queue at the same time.

4) If both the left block and the right block are occupied blocks, then modify the occupancy flag of this block to be free, and insert it into the free block queue.

After merging the reclaimed block and the adjacent free block, modify the head pointer of the free list to point to the newly merged free block, and then search for free intervals backward from the reclaimed block when allocating. Its flow chart is shown in Figure 3.

Segmented Temporary Space Storage Management Mechanism Based on Context and Event Attributes in Multi-Applet Runtime Environment

The traditional storage allocation method will inevitably cause address conflicts for the CLEAR_ON_DESELECT storage space sharing scheme in a multi-Applet operating environment. At the same time, due to the static allocation of CLEAR_ON_RESET space, when the installed Applets on the card use up the existing CLEAR_ON_RESET space, subsequent The Applet can no longer be downloaded and installed on the card.

In order to solve the above problems, the present invention organizes the temporary arrays in the same context with the same event attribute in the same storage segment and creates a root node for each segment in the persistent storage space and points to the array handle queue of the corresponding event attribute. There are actually two array handle queues per context, the CLEAR_ON_RESET and CLEAR_ON_DESELECT event attribute queues. At runtime, a context also corresponds to two corresponding temporary storage segments.

The present invention sets a corresponding segment base address register for each storage segment, the storage address of the val_address element in the array handle is the offset in the segment, and the actual physical address is obtained by adding the offset to the base address. In addition, the CLEAR_ON_RESET and CLEAR_ON_DESELECT storage segments are allocated from both ends of the temporary space (high address end and low address end), where the growth direction of the CLEAR_ON_RESET segment is from high address to low address, and the growth direction of CLEAR_ON_DESELECT segment is from low address To the high address, so as to avoid the overlapping coverage of the two address spaces.

If the length of the array allocated by the current request is length, the array type is type, and the root node of the array handle queue of the corresponding event attribute is root, the process of creating a new temporary array object is described as follows:

Array_Handle ^* AllocateTransientObject()

{

pre_p=p=root;

while(p<>null)

{

if((p->ref_tag==0)&&(p->length==length)&&

(p->item_type==type))

{

//Reuse the existing unreferenced object space

return p;

}

else

{

pre_p=p;

p=p->next;

}

}

pre_p->next=new(Array_Handle);

pre_p->next->val_address=AllocateMemoryBlock(pre_p);

return pre->next;

}

The new() function is used to allocate the Array_Handle structure in the persistent space and return the first address. The AllocateMemoryBlock() function is used to allocate temporary storage space. The entry parameter pointer p is the tail pointer of the current queue. The function definition is as follows:

u2 AllocateMemoryBlock(Array_handle ^* p)

{

if (enough temporary space available)

{

Address=p->val_address+p->length;

return address;

}

else

{

Invoke the temporary space garbage collection process;

if (enough temporary space available)

{

Address=p->val_address+p->length;

return address;

}

else

{

Throw a temporary space memory overflow exception;

}

}

}

After the Applet belonging to a certain context is successfully selected, the temporary storage space management process will determine the value of the segment base address register for the two event attribute storage segments in this context according to the current memory usage and traverse the temporary object queue for space Allocation and initialization, taking into account the temporary object allocation of Applet at runtime, a certain reserved space is allocated in each storage segment according to the current available space. In order to store these information related to storage segments, the system maintains a segment descriptor (up to 8) data structure in RAM for each allocated segment at runtime, which is defined as follows:

Segment_Descriptor

{

u2 Base / segment base address register

u1 event_type //event attribute RESET or DESELECT

u2 Length // segment length

u2 Reserve_length //Reserved space length

u1 context //object context

u1 Non_ref_length // Length of unreferenced space

}

Figure 4 shows the temporary space allocation when multiple Applet instances are running.

When a context is started, the process of the system allocating temporary space storage segments is described as follows:

void AllocateSegment(ulcontext)

{

s points to the first segment descriptor in the segment descriptor table;

while(s<>null)

{

If((s->context==0)&&(s->Length>request length))

{

s->context=context;

Set s->Reserve_length;

Set s->Non_ref_length;

Set s->event_type;

return;

}

s points to the next descriptor;

}

Storage compaction in units of storage segments;

if (not enough temporary storage available)

{

Throw a temporary space memory overflow exception;

}

else

{

//Set the corresponding segment descriptor

s->context=context;

Set s->Length;

Set s->Reserve_length;

Set s->Non_ref_length;

Set s->event_type;

return;

}

}

garbage collection management

Some existing garbage collection management mechanisms are not fully applicable to the smart card environment with very limited resources. Therefore, we give an object mark recovery method for the temporary storage space on the card under the comprehensive consideration of response speed and limited resources.

Temporary objects initially created by the system are marked as unreferenced. Objects referenced by variables in the persistent system cannot be recycled. Therefore, in the design of the bytecode interpreter, for all instructions that assign values to the reference field, the type of the referenced object is judged and the temporary object is marked. If p is an object pointer, the marking process is as follows:

The assignment marking process of persistent reference variables is as follows:

if(p->tag==00) //temporary object

p->ref_tag=02; //persistent reference

The assignment marking process of local reference variables is as follows:

if((p->tag==00) //temporary object

&&(p->ref_tag==00)) //Not referenced

p->ref_tag=01; //local variable reference

Due to the limited resources on the card and the requirements of real-time response characteristics, it is not feasible to perform precise garbage collection on the card according to the local variables in the Java stack. So we choose the mark point of garbage collection after the Applet's select (), process (), and deselect () methods return. At this time, the Java stack is empty, so objects only referenced by local variables should be recycled. Therefore, at the marking point, the object in the queue pointed to by root should be remarked. If the corresponding segment descriptor pointer is s, the marking process is as follows:

p = root;

while(p<>null)

{

if(p->ref_tag==01)

{

//Local variable reference, marked as unreferenced and added to the unreferenced space of the segment descriptor

p->ref_tag=00;

s->Non_ref_length+=p->length;

}

else

{

p=p->next;

}

}

Since the Applet will not be changed after being downloaded to the smart card and will run multiple times, the probability of multiple running references to the same temporary object is very high, so we do not remove it from the temporary object referenced by the local variable during the marking process. Deleted from the queue. In this way, this section of RAM space is reserved when the context is re-running, so as to facilitate the reuse of temporary objects.

When an applet requests to allocate a temporary object and no temporary space is available, the system starts the garbage collection process. The policy steps of garbage collection are as follows:

1) In order to meet the real-time response characteristics, an incremental garbage collection strategy is adopted, and the recycling process ends when the required storage space is available.

2) On the premise that the temporary object in the current running context has a high reuse rate, the storage segment corresponding to the currently unrunning context is preferentially garbage collected.

3) Prioritize the recovery of reserved storage space.

4) The adjacent storage segments of the current running context storage segment are preferentially garbage collected to reduce the amount of data movement.

5) If the required storage space cannot be provided after the above operations are completed, the unreferenced object space reserved in the non-running context storage segment is compacted and reclaimed.

6) Finally, perform storage compaction and reclaim the unreferenced object space reserved in the storage segment of the running context.

The garbage collection process of temporary objects is described as follows:

void GarbageCollection()

{

Determine whether the reserved space meets the requirements according to the Reserve_length of the unrunning context storage segment in the segment descriptor table;

if (reserved space meets demand)

{

Reclaim the reserved space in the non-running context storage segment;

Move the corresponding storage segment and change the segment base address register;

return;

}

According to the Non_ref_length of the non-running context storage segment in the segment descriptor table, it is judged whether the unreferenced space meets the requirement;

if (unreferenced space meets requirements)

{

Carry out storage compaction and reclaim the unreferenced object space reserved in the non-running context storage segment

receive;

Move the corresponding storage segment and change the segment base address register;

return;

}

According to the Non_ref_length of all context storage segments in the segment descriptor table, it is judged whether the unreferenced space meets the requirement;

if (unreferenced space meets requirements)

{

Carry out storage compaction and reclaim the unreferenced object space reserved in the corresponding context storage segment

receive;

return;

}

if (the sum of the above two meets the requirements)

{

The above-mentioned recycling process is carried out separately;

return;

}

}

If p and pre_p are array handle pointers, root is the queue root node, and s is a segment descriptor pointer, then the storage compaction process for the reserved unreferenced object space is described as follows:

void NonRefContraction()

{

pre_p=p=root;

while(p<>null)

{

If(p->ref_tag==00)

{

// Unreferenced object

  s->Non_ref_length-=p->length;

for(;subsequent reference object node of p in the queue;)

{

    val_address-=p->length;

}

p=p->next;

 dispose(pre_p->next);

Pre_p->next=p;

}

else

{

pre_p=p;

p=p->next;

}

}

}

When the current context exits the running environment, the entire temporary space corresponding to it should be reclaimed by the system, that is, all storage segments corresponding to this context are reclaimed. If the current context is Current_context, s is the segment descriptor pointer, and the reclaiming process is described as follows:

while (the segment corresponding to Current_context has not been recycled)

{

if(s->context==Current_context)

{

//context is 0 means the current segment descriptor is not used

s->context=0;

}

s points to the next descriptor;

}

To sum up, the present invention provides a management method for the storage environment of a smart card. In the management method, a two-way linked list structure is used for persistent space management, which can easily insert or delete a record, and at the same time conveniently make the detection pointer forward and Rear drive direction movement, so it is easy to instantiate objects or allocate or delete application storage space. Effectively save the limited computing resources and storage resources of the smart card platform. In this management method, a segmented storage management mechanism is adopted for the temporary space, which effectively avoids the address conflict problem in the traditional control method, and enhances the adaptability of space allocation and recycling operation, which is very suitable for the operating environment of smart cards.

Claims (9)

1. the control method of a smart card storage environment, described smart card is made of CPU, RAM storer, ROM storer, eeprom memory, logical operation module, crypto engine module, interruption processing module, CRC generator, randomizer, timer and external interface, described RAM storer is used to store ephemeral data information, described ROM storer and eeprom memory are used to store persistant data information, and it is characterized in that has the data information memory step of outside input:

(A) data message to described outside input carries out the storage class classification, obtains storage class,

Described storage class has first storage class, is used to realize the storage administration in lasting space; With

Second storage class is used to realize the storage administration of the temporary space of CLEAR_ON_RESET attribute; With

The 3rd storage class is used to realize the storage administration of the temporary space of CLEAR_ON_DESELECT attribute;

(B) the described storage class after handling through (A) storage classification is stored control according to storage rule, its first storage class is stored in the eeprom memory; Second storage class and the 3rd storage class are stored in the RAM storer,

Described storage rule has first storage rule, is used for described first storage class is stored and reclaimed according to the doubly linked list structure, and adaptive method is first adopted in storage, reclaims and adopts the space act of union; Second storage rule is used for described second storage class is begun to store to low address according to the high address end from temporary space, reclaims and adopts the object tag absorption method; The 3rd storage rule is used for described the 3rd storage class is begun to store to high address according to the low address end from temporary space, reclaims and adopts the object tag absorption method.

2. the control method of smart card storage environment according to claim 1, it is characterized in that: the adaptive method first that first storage rule in the storage rule carries out the doubly linked list storage organization to described first storage class is, searches the free block M that satisfies free block size size 〉=n by the data message amount n of input in head pointer pav idle chained list pointed; When free block size size-n≤10 bytes, directly this free block is distributed to the data message of input; When free block size size-n＞10 bytes, M is divided into two parts with free block, and the memory allocation that wherein is equal to the data message amount n of input is given the data message of input; Remainder is inserted in the idle chained list as free block; Turn back to allocation pointer after the data message amount n of described input assigned, and to revise head pointer pav be next free block of free block M, finish the adaptive first of first storage class; Output error message and finish the adaptive first of first storage class when free blocks all in the idle chained list is not satisfied size 〉=n.

3. the control method of smart card storage environment according to claim 1, it is characterized in that: the space act of union that first storage rule in the storage rule carries out the employing of doubly linked list recovery structure to described first storage class is, to reclaiming the idle determination that space piece H carries out adjacent block, as left space piece H _LDuring for the free time, then will reclaim space piece H and left space piece H _LMerge, substitute left space piece H with the space piece after the described merging _LPosition in idle chained list, and revise the head pointer pav of idle chained list, make the space piece after head pointer pav points to described merging; As right space piece H _RDuring for the free time, then will reclaim space piece H and right space piece H _RMerge, substitute right space piece H with the space piece after the described merging _RPosition in idle chained list, and revise the head pointer pav of idle chained list, make the space piece after head pointer pav points to described merging; As left space piece H _LWith right space piece HR when all idle, with right space piece H _RWith left space piece H _LSpace piece H merges with recovery, substitutes left space piece H with the space piece after the described merging _L, and in idle chained list, delete right space piece H _R, revise the head pointer pav of idle chained list, make the space piece after head pointer pav points to described merging; As left space piece H _LWith right space piece H _RWhen not idle, revise to reclaim space piece H busy flag item, amended recovery space piece H is inserted into the heading of idle chained list, revise the head pointer pav of idle chained list, make head pointer pav point to described amended recovery space piece H.

4. the control method of smart card storage environment according to claim 1, it is characterized in that: second storage rule in the storage rule be described second storage class is begun to the method that low address is stored according to the high address end from temporary space be, same context is had in the same memory paragraph of ephemeral data information stores in temporary space in the CLEAR_ON_RESET event attribute, and be that described memory paragraph is created a root node and pointed to the array handle formation of CLEAR_ON_RESET event attribute in lasting space; Be provided with the segment base register on described memory paragraph, the section bias internal amount val_address element memory address addition in described segment base register and the described array handle obtains storing the physical address of data.

5. the control method of smart card storage environment according to claim 1 is characterized in that: second storage rule in the storage rule is described second storage class to be reclaimed adopt object tag absorption method, described object tag absorption method removal process to be,

1) carries out the assignment mark according to the object in the described pointer to object p temporary space pointed, the data message of described assignment mark is quoted by lasting space and is designated as " 02 ", the data message of described assignment mark is quoted by the local variable in the present frame and is designated as " 01 ", and the data message of described assignment mark is not cited and is designated as " 00 ";

2) object to described mark " 02 ", described mark " 01 " and described mark " 00 " institute mark carries out the increment type garbage reclamation.

6. the control method of smart card storage environment according to claim 5, it is characterized in that: described increment type garbage reclamation step has, 1. the data message that is stored in the temporary space in the smart card is preferentially carried out the garbage reclamation of the memory paragraph of current off-duty context correspondence, information after the described recovery is satisfied requisite space, then finish to reclaim; 2. described information after 1. step reclaims is not satisfied requisite space, then reclaim the storage space of reserving; 3. described information after 1. and 2. step reclaims is not satisfied requisite space, then reclaim the adjacent memory paragraph of current operation context memory paragraph; 4. described information after 1., 2. and 3. step reclaims is not satisfied requisite space, then reclaim the unreferenced object space of reserving in the off-duty context memory paragraph; 5. described information after 1., 2., 3. and 4. step reclaims is not satisfied requisite space, then reclaim the unreferenced object space of reserving in the contextual memory paragraph of operation.

7. the control method of smart card storage environment according to claim 1, it is characterized in that: the 3rd storage rule in the storage rule be described the 3rd storage class is begun to the method that high address is stored according to the low address end from temporary space be, same context is had in the same memory paragraph of ephemeral data information stores in temporary space in the CLEAR_ON_DESELECT event attribute, and be that described memory paragraph is created a root node and pointed to the array handle formation of CLEAR_ON_DESELECT event attribute in lasting space; Be provided with the segment base register on described memory paragraph, the section bias internal amount val_address element memory address addition in described segment base register and the described array handle obtains storing the physical address of data.

8. the control method of smart card storage environment according to claim 1 is characterized in that: the 3rd storage rule in the storage rule is described the 3rd storage class to be reclaimed adopt object tag absorption method, described object tag absorption method removal process to be,

1) carries out the assignment mark according to the object in the described pointer to object p temporary space pointed, the data message of described assignment mark is quoted by lasting space and is designated as " 02 ", the data message of described assignment mark is quoted by the local variable in the present frame and is designated as " 01 ", and the data message of described assignment mark is not cited and is designated as " 00 ";

2) object to described mark " 02 ", described mark " 01 " and described mark " 00 " institute mark carries out the increment type garbage reclamation.

9. the control method of smart card storage environment according to claim 8, it is characterized in that: described increment type garbage reclamation step has, 1. the memory paragraph that the data message that is stored in the temporary space in the smart card is carried out current off-duty context correspondence carries out preferential garbage reclamation, information after the described recovery is satisfied requisite space, then finish to reclaim; 2. described information after 1. step reclaims is not satisfied requisite space, then reclaim the storage space of reserving; 3. described information after 1. and 2. step reclaims is not satisfied requisite space, then reclaim the adjacent memory paragraph of current operation context memory paragraph; 4. described information after 1., 2. and 3. step reclaims is not satisfied requisite space, then reclaim the unreferenced object space of reserving in the off-duty context memory paragraph; 5. described information after 1., 2., 3. and 4. step reclaims is not satisfied requisite space, then reclaim the unreferenced object space of reserving in the contextual memory paragraph of operation.

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