1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
// use crate::compressed_numbers::CompressedU64;
// use borsh::{BorshDeserialize, BorshSerialize};
// use cruiser::bytes_ext::ReadExt;
// use solana_program::program_memory::sol_memcpy;
// use std::io::{Read, Write};
// use std::mem::size_of;
//
// #[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq)]
// pub struct ZeroCount<T>(T);
// impl ZeroCount<u64> {
// const BYTES_NEEDED_LOOKUP_TABLE: &'static [u8] = &[
// 9, 9, 9, 9, 9, 9, 9, 9, 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 7, 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 5,
// 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1,
// 1, 1, 1, 1, 1,
// ];
// const MAX_BYTES_NEEDED: u8 = {
// let mut max = u8::MIN;
// let mut index = 0;
// loop {
// if index >= Self::BYTES_NEEDED_LOOKUP_TABLE.len() {
// break;
// }
// if Self::BYTES_NEEDED_LOOKUP_TABLE[index] > max {
// max = Self::BYTES_NEEDED_LOOKUP_TABLE[index];
// }
// index += 1;
// }
// max
// };
//
// const fn from_u64(number: u64) -> Self {
// Self(number)
// }
//
// const fn into_u64(self) -> u64 {
// self.0
// }
// }
// unsafe impl CompressedU64 for ZeroCount<u64> {
// fn from_u64(number: u64) -> Self {
// Self::from_u64(number)
// }
//
// fn into_u64(self) -> u64 {
// self.into_u64()
// }
//
// fn num_bytes(self) -> usize {
// todo!()
// }
// }
// impl BorshSerialize for ZeroCount<u64> {
// fn serialize<W: Write>(&self, writer: &mut W) -> std::io::Result<()> {
// let zeros = self.0.leading_zeros() as usize;
// let bytes_needed = Self::BYTES_NEEDED_LOOKUP_TABLE[zeros] as usize;
// let mut bytes = [0; Self::MAX_BYTES_NEEDED as usize];
// sol_memcpy(&mut bytes[1..], &self.0.to_be_bytes(), size_of::<u64>());
// let start_byte = bytes.len() - bytes_needed;
// bytes[start_byte] |= (1 << 7) >> (bytes_needed - 1);
// writer.write_all(&bytes[start_byte..])
// }
// }
// impl BorshDeserialize for ZeroCount<u64> {
// fn deserialize(buf: &mut &[u8]) -> std::io::Result<Self> {
// let first_byte = buf.read_u8()?;
// let leading_zeros = first_byte.leading_zeros() as usize;
// let mut bytes = [0; size_of::<u64>()];
// let write_offset = if leading_zeros != 8 {
// let write_offset = 7 - leading_zeros;
// bytes[write_offset] = first_byte & !(1 << write_offset);
// write_offset + 1
// } else {
// 0
// };
// buf.read_exact(&mut bytes[write_offset..])?;
// Ok(Self(u64::from_le_bytes(bytes)))
// }
// }
//
// #[cfg(test)]
// mod test {
// use super::*;
// use rand::{thread_rng, Rng};
// #[test]
// fn serde_test() {
// let mut rng = thread_rng();
// for index in 0..u64::BITS as usize {
// let val =
// ((rng.gen::<u64>() << index) >> index) & (1 << (size_of::<u64>() - index - 1));
// let before = ZeroCount::from_u64(val);
// let data = before.try_to_vec().unwrap();
// let after = ZeroCount::try_from_slice(&data).unwrap();
// assert_eq!(before, after);
// }
// }
// }