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use std::fs::File;
use std::num::NonZeroU64;
// cargo run --example reflink_block V:/file.bin V:/file_cow.bin 4096
fn main() -> std::io::Result<()> {
let args: Vec<_> = std::env::args().collect();
let [_, src_file, tgt_file, cluster_size] = &args[..] else {
eprintln!(
"Usage: {} <source_file> <target_file> <cluster_size>",
args[0]
);
return Ok(());
};
let cluster_size: NonZeroU64 = cluster_size.parse().expect("cannot parse cluster size");
let from_file = File::open(src_file)?;
let len = from_file.metadata()?.len();
let to_file = File::create(tgt_file)?;
to_file.set_len(len)?;
let mut offset = 0u64;
while offset < len {
let src_length = if cfg!(windows) {
// Windows API clones the entire cluster regardless of the number of bytes actually used
// by the file in that cluster.
cluster_size
} else {
cluster_size.min(NonZeroU64::new(len - offset).unwrap())
};
println!("reflink {offset}, {src_length}");
reflink_copy::ReflinkBlockBuilder::new(&from_file, &to_file, src_length)
.from_offset(offset)
.to_offset(offset)
.cluster_size(cluster_size)
.reflink_block()?;
offset += src_length.get();
}
Ok(())
}
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