C compatible version for golang-klauspost-reedsolomon.
It can run in platform of MIPS/ARM/i386/x64 of linux, especially for some embedded projects.
It's really simple, with a little change, it can run in other platform.
Copy rs.c and rs.h to your projects and make it.
This section assumes you know the basics of Reed-Solomon encoding. A good start is this Backblaze blog post.
To create an encoder/decoder with 10 data shards (where your data goes) and 3 parity shards (calculated):
reed_solomon* rs = reed_solomon_new(10, 3);
Destroy:
reed_solomon_relelase(rs);
Encode:
Look at test_create_encoding
int test_create_encoding(
reed_solomon *rs,
unsigned char *data,
int data_size,
int block_size
) {
unsigned char **data_blocks;
int data_shards, parity_shards;
int i, n, nr_shards, nr_blocks, nr_fec_blocks;
data_shards = rs->data_shards;
parity_shards = rs->parity_shards;
nr_blocks = (data_size+block_size-1)/block_size;
nr_blocks = ((nr_blocks+data_shards-1)/data_shards) * data_shards;
n = nr_blocks / data_shards;
nr_fec_blocks = n * parity_shards;
nr_shards = nr_blocks + nr_fec_blocks;
data_blocks = (unsigned char**)malloc(nr_shards * sizeof(unsigned char*));
for(i = 0; i < nr_shards; i++) {
data_blocks[i] = data + i*block_size;
}
n = reed_solomon_encode2(rs, data_blocks, nr_shards, block_size);
free(data_blocks);
return n;
}
Decode:
Look at test_data_decode
int test_data_decode(
reed_solomon *rs,
unsigned char *data,
int data_size,
int block_size,
int *erases,
int erase_count) {
unsigned char **data_blocks;
unsigned char *zilch;
int data_shards, parity_shards;
int i, j, n, nr_shards, nr_blocks, nr_fec_blocks;
data_shards = rs->data_shards;
parity_shards = rs->parity_shards;
nr_blocks = (data_size+block_size-1)/block_size;
nr_blocks = ((nr_blocks+data_shards-1)/data_shards) * data_shards;
n = nr_blocks / data_shards;
nr_fec_blocks = n * parity_shards;
nr_shards = nr_blocks + nr_fec_blocks;
data_blocks = (unsigned char**)malloc(nr_shards * sizeof(unsigned char*));
for(i = 0; i < nr_shards; i++) {
data_blocks[i] = data + i*block_size;
}
zilch = (unsigned char*)calloc(1, nr_shards);
for(i = 0; i < erase_count; i++) {
j = erases[i];
memset(data + j*block_size, 137, block_size);
zilch[j] = 1; //mark as erased
}
n = reed_solomon_reconstruct(rs, data_blocks, zilch, nr_shards, block_size);
free(data_blocks);
free(zilch);
return n;
}
I have implemented a benchmarkEncode in test_rs.c. but is this implement right ? it's so quick, I think there maybe some mistake in benchmark test.
Implement a tool to test C and golang version.
simple-encoder.c VS simple-encoder.go
go build -o go-simple-encoder ../simple-encoder.go
./go-simple-encoder --data 12 --par 6 --out o input.txt
./simple-encoder -d 12 -p 6 -o o2 -f input.txt
meld o o2
published under an MIT license. See LICENSE file for more information.