can we modify the data in ch or hs callback

[ffashion]

if we memset the data, What impact will this have?

[ffashion]

for example, memset(ctx->data + from, '*' , to -from);

[hongyang7]

We suggest not to modify the input buffer, as hyperscan may do reverse scan over input data, especially in SOM mode (when HS_FLAG_SOM_LEFTMOST flag is set).