CN118838749A - Construction and data reading method of expandable storage structure - Google Patents

Abstract

The invention belongs to the technical field of embedded system data storage, and particularly relates to a method for constructing an expandable storage structure and reading data, which comprises the following steps: a set of base data elements; a check value Crc1 for checking the data integrity of the base data element group; a check value Crc for checking the data integrity including the base data element group and the check value Crc; an extended data element group, at least one extended data element group is newly added after the check value Crc; check value Crc for checking the data integrity of the extended data element group. After expanding the storage structure, check value Crc is updated to check the data integrity including the base data element group, check value Crc1, expanded data element group, and check value Crc. The construction method of the invention enables users to add data elements at any time according to requirements, has no problem of data compatibility of old version, and can not cause that the whole data is unavailable when the data in the storage space is destroyed, and the data with successful partial verification is credible.

Description

A method for constructing an expandable storage structure and reading data

Technical Field

The invention belongs to the technical field of embedded system data storage, and in particular relates to a construction method of an expandable storage structure and a data reading method.

Background Art

In embedded systems, structures are often used to store related data. After the project is mass-produced, the data structure has been determined. However, when considering expansion later, it is often found that it is difficult to add new elements to the same structure because of forward compatibility issues. The usual practice is to first use the structure of the old version of the software to read out the related data when compatible with the structure of the old version of the software, and then assign it to the elements in the structure of the new version of the software, and then recalculate the CRC and store it in the non-volatile flash.

Then the above data structure still has the following problems when adding elements:

1. The CRC of the entire structure is generally stored at the end of the structure. When a new data element is added to the structure, the position of the CRC will change. When a new structure is used to read the old structure data, the calculated CRC will not match, causing the data that has been correctly stored in the old structure to be unreliable and the data needs to be stored again.

2. Reserve some data elements in advance for subsequent expansion and addition of new data, which will result in a waste of some storage space, which may never be used.

Summary of the invention

The purpose of the present invention is to provide a method for constructing an expandable storage structure and reading data. By adding new data elements and their check values on the basis of the existing structure and performing corresponding check processing when reading data, the function of dynamically expanding data elements is realized without changing the original data structure, so as to solve the problems raised in the background technology.

The present invention achieves the above-mentioned purpose through the following technical solutions:

In a first aspect, the present invention proposes a method for constructing an extensible storage structure, the method comprising defining the following data structure:

at least one basic data element group, the basic data element group comprising data elements Datax ₁ -Datax _n ;

A check value Crc1, used to check the data integrity of the basic data element group;

A check value Crc, used to check the integrity of data including the basic data element group and the check value Crc1;

At least one extended data element group, the extended data element group comprising data elements Datay ₁ -Datay _n , and at least one extended data element group added after the check value Crc1;

A check value Crc2, used to check the data integrity of the extended data element group;

The construction method further includes: after expanding the storage structure, updating the check value Crc so as to check the integrity of data including the basic data element group, the check value Crc1, the extended data element group and the check value Crc2.

A further improvement is that the check value Crc1, the check value Crc2, and the check value Crc are all calculated by CRC16 algorithm to check the integrity of the corresponding data.

In a second aspect, the present invention proposes a method for reading data from an expandable storage structure, using the storage structure constructed by the above construction method to read data, the data reading method comprising:

Using the storage structure to read the target data structure, first verifying the check value Crc, and selecting whether to enter the compatible processing mode according to the check result of the check value Crc;

In the compatible processing mode, the check value Crc1 and the check value Crc2 are checked respectively, the values of the data element groups that pass the check are retained, the extended data element groups that fail the check are cleared or set to default values, and the check values of each data element are recalculated during the next storage, and the check value Crc is updated.

A further improvement is that the target data structure includes the at least one basic data element group.

A further improvement is that if the verification result of the verification value Crc passes, the data reading process is terminated.

The beneficial effects of the present invention are:

1. The construction method proposed in the present invention allows users to add data elements at any time according to their needs, and there will be no compatibility issues with old versions of data. When the storage space data is damaged, it will not cause the entire data to be unavailable, and the data that has been partially verified can be trusted.

2. The reading method proposed in the present invention can automatically determine the credibility and integrity of the data by verifying the total check value and the check value of each data element when reading data, and take corresponding processing measures to ensure the accuracy and reliability of the data; and the reading method has good forward compatibility and can support the storage and reading of new version data without affecting the old version data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a method for constructing an expandable storage structure provided in Example 1 of the present application.

FIG2 is a flow chart of a method for reading data from an expandable storage structure provided in Example 2 of the present application.

FIG3 is a schematic diagram of the code implementation process of the old version storage structure in the example provided in the specific implementation manner of this application.

FIG. 4 is a schematic diagram of the code implementation process of the new version storage structure in the example provided in the specific implementation manner of the present application.

DETAILED DESCRIPTION

The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

Example 1

As shown in Figure 1, this embodiment proposes a method for constructing an expandable storage structure, which includes defining the following data structures: defining at least one basic data element group, the basic data element group including data elements _Datax1 - _Dataxn ; defining a check value Crc1 for verifying the data integrity of the basic data element group; defining a check value Crc for verifying the data integrity of the basic data element group and the check value Crc1; defining at least one extended data element group, the extended data element group including data elements _Datay1 - _Datayn , and adding at least one extended data element group after the check value Crc1; defining a check value Crc2 for verifying the data integrity of the extended data element group.

The construction method also includes: after the storage structure is expanded, updating the check value Crc so that it verifies the data integrity including the basic data element group, the check value Crc1, the extended data element group and the check value Crc2.

In this embodiment, Datax ₁ -Datax _n are data elements, that is, data information to be stored, Crc1 is a data check of Datax ₁ -Datax _n , obtained by CRC16 calculation, and Crc is a data check of Datax ₁ -Datax _n and Crc1, obtained by CRC16 calculation.

When the storage structure of the present invention needs to expand storage capacity, new data elements _Datay1 - _Datayn and corresponding check value Crc2 are added after Crc1. At the same time, Crc will be updated to the check of the entire expanded structure (including Datax1 _{- Dataxn} , Crc1, _Datay1 - _Datayn and Crc2).

It can be understood that what the construction method in this embodiment needs to solve is that users can add data elements at any time according to their needs, and there will be no compatibility issues with old versions of data. When the storage space data is damaged, it will not cause the entire data to be unavailable, and some data that has successfully been verified can be trusted.

Correspondingly, the check value Crc1, the check value Crc2, and the check value Crc are all calculated by the CRC16 algorithm to check the integrity of the corresponding data.

According to the above-mentioned embodiment of the present invention, this embodiment realizes the function of dynamically extending data elements without changing the original data structure by adding optional data elements and their check values.

Example 2

As shown in FIG. 2 , this embodiment proposes a method for reading data from an expandable storage structure, using the storage structure constructed by the construction method in Embodiment 1 to read data. The data reading method includes:

Use the storage structure to read the target data structure, first verify the check value Crc, and choose whether to enter the compatible processing mode according to the verification result of the check value Crc; in the compatible processing mode, check the check value Crc1 and the check value Crc2 respectively, retain the values of the data element groups that pass the verification, clear the extended data element groups that fail the verification or set them to default values, and recalculate the check value of each data element at the next storage, and update the check value Crc.

Further preferably, if the verification result of the verification value Crc passes, the data reading process is terminated.

Further preferably, the target data structure includes at least one basic data element group Datax ₁ -Datax _n .

In some preferred embodiments, the storage structure constructed by Example 1 can be understood as the new version structure data, the target data structure can be understood as the old version structure data, and the above data reading method can be understood as using the new version structure to try to read the old version of data. Due to the change in the data structure, the CRC check will not pass, indicating that the complete data is not credible. Then, by checking the values of CRC1 and CRC2 respectively, the credibility of _Datax1 - _Dataxn can be determined, while _Datay1 - _Datayn is considered untrustworthy due to the failure of CRC2 check, and it is cleared. When storing next time, each CRC value is recalculated and stored, so as to achieve the reading of the old version data and the compatibility of the new version data.

According to the above-mentioned embodiment of the present invention, based on the above-mentioned data reading method, when reading data, by verifying the total check value (Crc value) and the check value of each data element, it is possible to automatically judge the credibility and integrity of the data, and take corresponding processing measures to ensure the accuracy and reliability of the data; and the reading method has good forward compatibility, and can support the storage and reading of new version data without affecting the old version data.

The following further describes the construction of the extended storage structure and the method for reading data in the present invention in conjunction with a specific example.

As an example, a structure initially defined by the user is used as a target data structure, including at least one basic data element group Data1-Data4. After the product related to the structure is mass-produced, when the subsequent newly developed functions need to add two elements Data5 and Data6, in order to be forward compatible and not affect the values of the basic data element group Data1-Data4, based on the design of the above-mentioned expandable storage structure of the present invention, specifically new elements Data5 and Data6 and a CRC16 check value Crc2 for Data5 and Data6 are added after Crc1. Crc is a total check of Data1~Data4, Crc1, Data5, Data6 and Crc2. The code implementation process is shown in Figures 3 and 4.

More specifically, in the above example, the data reading method based on the present invention is as follows: first, use the new version of the structure (expandable storage structure) to read the data of the old version (the target structure of at least one basic data element group). The number of verifications of Crc must fail, which means that the complete data read out is unreliable. At this time, check the values of Crc1 and Crc2 one by one. Under normal clearing, the Crc1 calculation is correct, so Data1~Data4 are reliable, and Crc2 is wrong, so Data5 and Data6 are unreliable. Clear the data to 0 or set it to the default value, and recalculate the value of each Crc when storing next time, and then re-store it. In this way, the reading of the old version of the data and the compatibility of the new version of the data can be automatically completed.

The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (5)

1. A method of constructing an expandable memory fabric, the method comprising defining a data structure comprising:

At least one base data element group, the base data element group comprising data elements Datax ₁-Datax_n;

a check value Crc1 for checking the data integrity of the set of base data elements;

A check value Crc for checking the data integrity including the set of base data elements and the check value Crc 1;

At least one extended data element group comprising data elements Datay ₁-Datay_n, the at least one extended data element group being added after the check value Crc 1;

a check value Crc for checking the data integrity of the set of extended data elements;

The construction method further comprises the following steps: after expanding the storage structure, the check value Crc is updated to check the data integrity including the base data element group, the check value Crc1, the expanded data element group, and the check value Crc.

2. The expandable memory structure of claim 1, wherein: the check value Crc, the check value Crc, and the check value Crc all calculate the integrity of the corresponding data by the CRC16 algorithm.

3. A data reading method of an expandable memory structure, for data reading using the memory structure constructed by the construction method of claim 1, characterized in that the data reading method comprises:

Reading a target data structure by using the storage structure, firstly verifying the check value Crc, and selecting whether to enter a compatible processing mode according to a check result of the check value Crc;

And in the compatible processing mode, checking the check value Crc and the check value Crc respectively, reserving the value of the checked data element group, resetting or setting the expanded data element group which fails to check as a default value, recalculating the check value of each data element when the data element group is stored next time, and updating the check value Crc.

4. A method of reading data of an expandable memory structure according to claim 3, wherein said target data structure comprises said at least one set of basic data elements.

5. A method of reading data from an expandable memory fabric according to claim 3, wherein the data reading process is terminated if the result of the check value Crc passes.