EC Interfaces

Include the EC encoding and decoding interfaces.

Interface Format

int KsalEcEncode(uint8_t **data, uint8_t **parity, struct HecParam *param);

int KsalEcDecode(uint8_t **data, uint8_t **parity, struct HecParam *param);

Parameters

Parameter	Type	Description	Input/Output
data	Pointer array	Indicates the pointer array of the data blocks.	Input/Output
parity	Pointer array	Indicates the pointer array of the parity blocks.	Input/Output
param	Pointer to codec parameters	Indicates the pointer to codec parameters.	Input
ret	Integer	Outputs 0 (success) or other values (failure).	Output

Data Structures

Member	Type	Description
dataNum	Integer	Indicates the number of data blocks.
parityNum	Integer	Indicates the number of parity blocks.
sectorSize	Integer	Indicates the sector size, which is the minimum codec granularity. Currently, 4096 and 4160 are supported.
blockSize	Integer	Indicates the size of a data block or parity block. The value must be an integer multiple of sectorSize.
targetColNum	Integer	Indicates the number of lost blocks, which is used by the decoding interface.
targetColArray[6]	Integer	Indicates the list of lost blocks. The value range of each entry is [0, dataNum + parityNum).
version	Integer	Indicates the algorithm version. The current version is 0.

Dependency

ksal/ksal_erasure_code.h

Example

Write the EC test code.

Create a test.c file.
```
vi test.c
```

Press i to enter the insert mode and add the following test code to the file:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ksal/ksal_erasure_code.h>

int main(int argc, char **argv)
{
    struct HecParam param = {4, 2, 4096, 8192, 2, {3, 4}};
    uint8_t tmp[20][8192];
    uint8_t *ptrs[20];
    uint8_t *bptrs[20];
    for (size_t i = 0; i < param.dataNum + param.parityNum; ++i) {
        for (size_t j = 0; j < param.blockSize; j++) {
                tmp[i][j] = (uint8_t)rand() & 0xff;
        }
        ptrs[i] = tmp[i];
        bptrs[i] = tmp[i];
    }
    KsalEcEncode(ptrs, ptrs + param.dataNum, &param);
    bptrs[3] = tmp[18];
    bptrs[4] = tmp[19];
    KsalEcDecode(bptrs, bptrs + param.dataNum, &param);
    if (memcmp(bptrs[3], ptrs[3], param.blockSize) == 0 &&
        memcmp(bptrs[4], ptrs[4], param.blockSize) == 0) {
        printf("decode succ!!\r\n");
    } else {
        printf("decode fail!!\r\n");
    }
    return 0;
}

Press Esc to exit the insert mode. Type :wq! and press Enter to save and exit the file.

Compile the test.c file into an executable file test.
```
gcc test.c -lksal -o test
```
Run the test executable file.
```
./test
```
The command output is as follows:
```
decode succ!!
```

Parent topic: KSAL Development Reference