vieter/src/util.v

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Coq
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module util
import os
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import io
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import crypto.md5
import crypto.sha256
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const reader_buf_size = 1_000_000
const prefixes = ['B', 'KB', 'MB', 'GB']
// Dummy struct to work around the fact that you can only share structs, maps &
// arrays
pub struct Dummy {
x int
}
// exit_with_message exits the program with a given status code after having
// first printed a specific message to STDERR
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[noreturn]
pub fn exit_with_message(code int, msg string) {
eprintln(msg)
exit(code)
}
// reader_to_file writes the contents of a BufferedReader to a file
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pub fn reader_to_file(mut reader io.BufferedReader, length int, path string) ? {
mut file := os.create(path) ?
defer {
file.close()
}
mut buf := []byte{len: util.reader_buf_size}
mut bytes_left := length
// Repeat as long as the stream still has data
for bytes_left > 0 {
// TODO check if just breaking here is safe
bytes_read := reader.read(mut buf) or { break }
bytes_left -= bytes_read
mut to_write := bytes_read
for to_write > 0 {
// TODO don't just loop infinitely here
bytes_written := file.write(buf[bytes_read - to_write..bytes_read]) or { continue }
to_write = to_write - bytes_written
}
}
}
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// hash_file returns the md5 & sha256 hash of a given file
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// TODO actually implement sha256
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pub fn hash_file(path &string) ?(string, string) {
file := os.open(path) or { return error('Failed to open file.') }
mut md5sum := md5.new()
mut sha256sum := sha256.new()
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buf_size := int(1_000_000)
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mut buf := []byte{len: buf_size}
mut bytes_left := os.file_size(path)
for bytes_left > 0 {
// TODO check if just breaking here is safe
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bytes_read := file.read(mut buf) or { return error('Failed to read from file.') }
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bytes_left -= u64(bytes_read)
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// For now we'll assume that this always works
md5sum.write(buf[..bytes_read]) or {
return error('Failed to update md5 checksum. This should never happen.')
}
sha256sum.write(buf[..bytes_read]) or {
return error('Failed to update sha256 checksum. This should never happen.')
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}
}
return md5sum.checksum().hex(), sha256sum.checksum().hex()
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}
// pretty_bytes converts a byte count to human-readable version
pub fn pretty_bytes(bytes int) string {
mut i := 0
mut n := f32(bytes)
for n >= 1024 {
i++
n /= 1024
}
return '${n:.2}${util.prefixes[i]}'
}