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use crate::block::hashtable::get_table_size;
use crate::block::hashtable::HashTable;
use crate::block::hashtable::{HashTableU16, HashTableU32, HashTableUsize};
use crate::block::END_OFFSET;
use crate::block::LZ4_MIN_LENGTH;
use crate::block::MAX_DISTANCE;
use crate::block::MFLIMIT;
use crate::block::MINMATCH;
use crate::sink::{vec_sink_for_compression, Sink, SliceSink};
use alloc::vec::Vec;
#[cfg(feature = "safe-encode")]
use core::convert::TryInto;
use super::{CompressError, WINDOW_SIZE};
const INCREASE_STEPSIZE_BITSHIFT: usize = 5;
#[inline]
#[cfg(not(feature = "safe-encode"))]
pub(super) fn get_batch(input: &[u8], n: usize) -> u32 {
unsafe { read_u32_ptr(input.as_ptr().add(n)) }
}
#[inline]
#[cfg(feature = "safe-encode")]
pub(super) fn get_batch(input: &[u8], n: usize) -> u32 {
let arr: &[u8; 4] = input[n..n + 4].try_into().unwrap();
u32::from_ne_bytes(*arr)
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
pub(super) fn get_batch_arch(input: &[u8], n: usize) -> usize {
unsafe { read_usize_ptr(input.as_ptr().add(n)) }
}
#[inline]
#[cfg(feature = "safe-encode")]
pub(super) fn get_batch_arch(input: &[u8], n: usize) -> usize {
const USIZE_SIZE: usize = core::mem::size_of::<usize>();
let arr: &[u8; USIZE_SIZE] = input[n..n + USIZE_SIZE].try_into().unwrap();
usize::from_ne_bytes(*arr)
}
#[inline]
fn token_from_literal(lit_len: usize) -> u8 {
if lit_len < 0xF {
(lit_len as u8) << 4
} else {
0xF0
}
}
#[inline]
fn token_from_literal_and_match_length(lit_len: usize, duplicate_length: usize) -> u8 {
let mut token = if lit_len < 0xF {
(lit_len as u8) << 4
} else {
0xF0
};
token |= if duplicate_length < 0xF {
duplicate_length as u8
} else {
0xF
};
token
}
#[inline]
#[cfg(feature = "safe-encode")]
fn count_same_bytes(input: &[u8], cur: &mut usize, source: &[u8], candidate: usize) -> usize {
const USIZE_SIZE: usize = core::mem::size_of::<usize>();
let cur_slice = &input[*cur..input.len() - END_OFFSET];
let cand_slice = &source[candidate..];
let mut num = 0;
for (block1, block2) in cur_slice
.chunks_exact(USIZE_SIZE)
.zip(cand_slice.chunks_exact(USIZE_SIZE))
{
let input_block = usize::from_ne_bytes(block1.try_into().unwrap());
let match_block = usize::from_ne_bytes(block2.try_into().unwrap());
if input_block == match_block {
num += USIZE_SIZE;
} else {
let diff = input_block ^ match_block;
num += (diff.to_le().trailing_zeros() / 8) as usize;
*cur += num;
return num;
}
}
#[cold]
fn count_same_bytes_tail(a: &[u8], b: &[u8], offset: usize) -> usize {
a.iter()
.zip(b)
.skip(offset)
.take_while(|(a, b)| a == b)
.count()
}
num += count_same_bytes_tail(cur_slice, cand_slice, num);
*cur += num;
num
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn count_same_bytes(input: &[u8], cur: &mut usize, source: &[u8], candidate: usize) -> usize {
let max_input_match = input.len().saturating_sub(*cur + END_OFFSET);
let max_candidate_match = source.len() - candidate;
let input_end = *cur + max_input_match.min(max_candidate_match);
let start = *cur;
let mut source_ptr = unsafe { source.as_ptr().add(candidate) };
const STEP_SIZE: usize = core::mem::size_of::<usize>();
while *cur + STEP_SIZE <= input_end {
let diff = read_usize_ptr(unsafe { input.as_ptr().add(*cur) }) ^ read_usize_ptr(source_ptr);
if diff == 0 {
*cur += STEP_SIZE;
unsafe {
source_ptr = source_ptr.add(STEP_SIZE);
}
} else {
*cur += (diff.to_le().trailing_zeros() / 8) as usize;
return *cur - start;
}
}
#[cfg(target_pointer_width = "64")]
{
if *cur + 4 <= input_end {
let diff = read_u32_ptr(unsafe { input.as_ptr().add(*cur) }) ^ read_u32_ptr(source_ptr);
if diff == 0 {
*cur += 4;
unsafe {
source_ptr = source_ptr.add(4);
}
} else {
*cur += (diff.to_le().trailing_zeros() / 8) as usize;
return *cur - start;
}
}
}
if *cur + 2 <= input_end
&& unsafe { read_u16_ptr(input.as_ptr().add(*cur)) == read_u16_ptr(source_ptr) }
{
*cur += 2;
unsafe {
source_ptr = source_ptr.add(2);
}
}
if *cur < input_end
&& unsafe { input.as_ptr().add(*cur).read() } == unsafe { source_ptr.read() }
{
*cur += 1;
}
*cur - start
}
#[inline]
#[cfg(feature = "safe-encode")]
fn write_integer(output: &mut impl Sink, mut n: usize) {
while n >= 0xFF {
n -= 0xFF;
push_byte(output, 0xFF);
}
push_byte(output, n as u8);
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn write_integer(output: &mut impl Sink, mut n: usize) {
if n >= 4 * 0xFF {
let bulk = n / (4 * 0xFF);
n %= 4 * 0xFF;
unsafe {
core::ptr::write_bytes(output.pos_mut_ptr(), 0xFF, 4 * bulk);
output.set_pos(output.pos() + 4 * bulk);
}
}
push_u32(output, 0xFFFFFFFF);
unsafe {
output.set_pos(output.pos() - 4 + 1 + n / 255);
*output.pos_mut_ptr().sub(1) = (n % 255) as u8;
}
}
#[cold]
fn handle_last_literals(output: &mut impl Sink, input: &[u8], start: usize) {
let lit_len = input.len() - start;
let token = token_from_literal(lit_len);
push_byte(output, token);
if lit_len >= 0xF {
write_integer(output, lit_len - 0xF);
}
output.extend_from_slice(&input[start..]);
}
#[inline]
#[cfg(feature = "safe-encode")]
fn backtrack_match(
input: &[u8],
cur: &mut usize,
literal_start: usize,
source: &[u8],
candidate: &mut usize,
) {
while *candidate > 0 && *cur > literal_start && input[*cur - 1] == source[*candidate - 1] {
*cur -= 1;
*candidate -= 1;
}
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn backtrack_match(
input: &[u8],
cur: &mut usize,
literal_start: usize,
source: &[u8],
candidate: &mut usize,
) {
while unsafe {
*candidate > 0
&& *cur > literal_start
&& input.get_unchecked(*cur - 1) == source.get_unchecked(*candidate - 1)
} {
*cur -= 1;
*candidate -= 1;
}
}
#[inline(never)]
pub(crate) fn compress_internal<T: HashTable, SINK: Sink, const USE_DICT: bool>(
input: &[u8],
input_pos: usize,
output: &mut SINK,
dict: &mut T,
ext_dict: &[u8],
input_stream_offset: usize,
) -> Result<usize, CompressError> {
assert!(input_pos <= input.len());
if USE_DICT {
assert!(ext_dict.len() <= super::WINDOW_SIZE);
assert!(ext_dict.len() <= input_stream_offset);
assert!(input_stream_offset
.checked_add(input.len())
.and_then(|i| i.checked_add(ext_dict.len()))
.map_or(false, |i| i <= isize::MAX as usize));
} else {
assert!(ext_dict.is_empty());
}
if output.capacity() - output.pos() < get_maximum_output_size(input.len() - input_pos) {
return Err(CompressError::OutputTooSmall);
}
let output_start_pos = output.pos();
if input_pos + LZ4_MIN_LENGTH > input.len() {
handle_last_literals(output, input, input_pos);
return Ok(output.pos() - output_start_pos);
}
let ext_dict_stream_offset = input_stream_offset - ext_dict.len();
let end_pos_check = input.len() - MFLIMIT;
let mut literal_start = input_pos;
let mut cur = input_pos;
if cur == 0 && input_stream_offset == 0 {
let hash = T::get_hash_at(input, 0);
dict.put_at(hash, 0);
cur = 1;
}
loop {
let mut step_size;
let mut candidate;
let mut candidate_source;
let mut offset;
let mut non_match_count = 1 << INCREASE_STEPSIZE_BITSHIFT;
let mut next_cur = cur;
loop {
step_size = non_match_count >> INCREASE_STEPSIZE_BITSHIFT;
non_match_count += 1;
cur = next_cur;
next_cur += step_size;
if cur > end_pos_check {
handle_last_literals(output, input, literal_start);
return Ok(output.pos() - output_start_pos);
}
let hash = T::get_hash_at(input, cur);
candidate = dict.get_at(hash);
dict.put_at(hash, cur + input_stream_offset);
debug_assert!(candidate <= input_stream_offset + cur);
if input_stream_offset + cur - candidate > MAX_DISTANCE {
continue;
}
if candidate >= input_stream_offset {
offset = (input_stream_offset + cur - candidate) as u16;
candidate -= input_stream_offset;
candidate_source = input;
} else if USE_DICT {
debug_assert!(
candidate >= ext_dict_stream_offset,
"Lost history in ext dict mode"
);
offset = (input_stream_offset + cur - candidate) as u16;
candidate -= ext_dict_stream_offset;
candidate_source = ext_dict;
} else {
debug_assert!(input_pos == 0, "Lost history in prefix mode");
continue;
}
if get_batch(candidate_source, candidate) == get_batch(input, cur) {
break;
}
}
backtrack_match(
input,
&mut cur,
literal_start,
candidate_source,
&mut candidate,
);
let lit_len = cur - literal_start;
cur += MINMATCH;
candidate += MINMATCH;
let duplicate_length = count_same_bytes(input, &mut cur, candidate_source, candidate);
let hash = T::get_hash_at(input, cur - 2);
dict.put_at(hash, cur - 2 + input_stream_offset);
let token = token_from_literal_and_match_length(lit_len, duplicate_length);
push_byte(output, token);
if lit_len >= 0xF {
write_integer(output, lit_len - 0xF);
}
copy_literals_wild(output, input, literal_start, lit_len);
push_u16(output, offset);
if duplicate_length >= 0xF {
write_integer(output, duplicate_length - 0xF);
}
literal_start = cur;
}
}
#[inline]
#[cfg(feature = "safe-encode")]
fn push_byte(output: &mut impl Sink, el: u8) {
output.push(el);
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn push_byte(output: &mut impl Sink, el: u8) {
unsafe {
core::ptr::write(output.pos_mut_ptr(), el);
output.set_pos(output.pos() + 1);
}
}
#[inline]
#[cfg(feature = "safe-encode")]
fn push_u16(output: &mut impl Sink, el: u16) {
output.extend_from_slice(&el.to_le_bytes());
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn push_u16(output: &mut impl Sink, el: u16) {
unsafe {
core::ptr::copy_nonoverlapping(el.to_le_bytes().as_ptr(), output.pos_mut_ptr(), 2);
output.set_pos(output.pos() + 2);
}
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn push_u32(output: &mut impl Sink, el: u32) {
unsafe {
core::ptr::copy_nonoverlapping(el.to_le_bytes().as_ptr(), output.pos_mut_ptr(), 4);
output.set_pos(output.pos() + 4);
}
}
#[inline(always)]
#[cfg(feature = "safe-encode")]
fn copy_literals_wild(output: &mut impl Sink, input: &[u8], input_start: usize, len: usize) {
match len {
0..=8 => output.extend_from_slice_wild(&input[input_start..input_start + 8], len),
9..=16 => output.extend_from_slice_wild(&input[input_start..input_start + 16], len),
17..=24 => output.extend_from_slice_wild(&input[input_start..input_start + 24], len),
_ => output.extend_from_slice_wild(&input[input_start..input_start + len], len),
}
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn copy_literals_wild(output: &mut impl Sink, input: &[u8], input_start: usize, len: usize) {
debug_assert!(input_start + len / 8 * 8 + ((len % 8) != 0) as usize * 8 <= input.len());
debug_assert!(output.pos() + len / 8 * 8 + ((len % 8) != 0) as usize * 8 <= output.capacity());
unsafe {
let start_ptr = input.as_ptr().add(input_start);
match len {
0..=8 => core::ptr::copy_nonoverlapping(start_ptr, output.pos_mut_ptr(), 8),
9..=16 => core::ptr::copy_nonoverlapping(start_ptr, output.pos_mut_ptr(), 16),
17..=24 => core::ptr::copy_nonoverlapping(start_ptr, output.pos_mut_ptr(), 24),
_ => core::ptr::copy_nonoverlapping(start_ptr, output.pos_mut_ptr(), len),
}
output.set_pos(output.pos() + len);
}
}
#[inline]
pub(crate) fn compress_into_sink(
input: &[u8],
output: &mut impl Sink,
) -> Result<usize, CompressError> {
let (dict_size, dict_bitshift) = get_table_size(input.len());
if input.len() < u16::MAX as usize {
let mut dict = HashTableU16::new(dict_size, dict_bitshift);
compress_internal::<_, _, false>(input, 0, output, &mut dict, b"", 0)
} else if input.len() < u32::MAX as usize {
let mut dict = HashTableU32::new(dict_size, dict_bitshift);
compress_internal::<_, _, false>(input, 0, output, &mut dict, b"", 0)
} else {
let mut dict = HashTableUsize::new(dict_size, dict_bitshift);
compress_internal::<_, _, false>(input, 0, output, &mut dict, b"", 0)
}
}
#[inline]
pub(crate) fn compress_into_sink_with_dict(
input: &[u8],
output: &mut impl Sink,
mut dict_data: &[u8],
) -> Result<usize, CompressError> {
let (dict_size, dict_bitshift) = get_table_size(input.len());
if dict_data.len() + input.len() < u16::MAX as usize {
let mut dict = HashTableU16::new(dict_size, dict_bitshift);
init_dict(&mut dict, &mut dict_data);
compress_internal::<_, _, true>(input, 0, output, &mut dict, dict_data, dict_data.len())
} else if dict_data.len() + input.len() < u32::MAX as usize {
let mut dict = HashTableU32::new(dict_size, dict_bitshift);
init_dict(&mut dict, &mut dict_data);
compress_internal::<_, _, true>(input, 0, output, &mut dict, dict_data, dict_data.len())
} else {
let mut dict = HashTableUsize::new(dict_size, dict_bitshift);
init_dict(&mut dict, &mut dict_data);
compress_internal::<_, _, true>(input, 0, output, &mut dict, dict_data, dict_data.len())
}
}
#[inline]
fn init_dict<T: HashTable>(dict: &mut T, dict_data: &mut &[u8]) {
if dict_data.len() > WINDOW_SIZE {
*dict_data = &dict_data[dict_data.len() - WINDOW_SIZE..];
}
let mut i = 0usize;
while i + core::mem::size_of::<usize>() <= dict_data.len() {
let hash = T::get_hash_at(dict_data, i);
dict.put_at(hash, i);
i += 3;
}
}
#[inline]
pub fn get_maximum_output_size(input_len: usize) -> usize {
16 + 4 + (input_len as f64 * 1.1) as usize
}
#[inline]
pub fn compress_into(input: &[u8], output: &mut [u8]) -> Result<usize, CompressError> {
compress_into_sink(input, &mut SliceSink::new(output, 0))
}
#[inline]
pub fn compress_into_with_dict(
input: &[u8],
output: &mut [u8],
dict_data: &[u8],
) -> Result<usize, CompressError> {
compress_into_sink_with_dict(input, &mut SliceSink::new(output, 0), dict_data)
}
#[inline]
pub fn compress_prepend_size(input: &[u8]) -> Vec<u8> {
let max_compressed_size = get_maximum_output_size(input.len());
let mut compressed = Vec::with_capacity(4 + max_compressed_size);
compressed.extend_from_slice(&(input.len() as u32).to_le_bytes());
let compressed_len = compress_into_sink(
input,
&mut vec_sink_for_compression(&mut compressed, 4, 0, max_compressed_size),
)
.unwrap();
compressed.truncate(4 + compressed_len);
compressed
}
#[inline]
pub fn compress(input: &[u8]) -> Vec<u8> {
let max_compressed_size = get_maximum_output_size(input.len());
let mut compressed = Vec::with_capacity(max_compressed_size);
let compressed_len = compress_into_sink(
input,
&mut vec_sink_for_compression(&mut compressed, 0, 0, max_compressed_size),
)
.unwrap();
compressed.truncate(compressed_len);
compressed
}
#[inline]
pub fn compress_with_dict(input: &[u8], ext_dict: &[u8]) -> Vec<u8> {
let max_compressed_size = get_maximum_output_size(input.len());
let mut compressed = Vec::with_capacity(max_compressed_size);
let compressed_len = compress_into_sink_with_dict(
input,
&mut vec_sink_for_compression(&mut compressed, 0, 0, max_compressed_size),
ext_dict,
)
.unwrap();
compressed.truncate(compressed_len);
compressed
}
#[inline]
pub fn compress_prepend_size_with_dict(input: &[u8], ext_dict: &[u8]) -> Vec<u8> {
let max_compressed_size = get_maximum_output_size(input.len());
let mut compressed = Vec::with_capacity(4 + max_compressed_size);
compressed.extend_from_slice(&(input.len() as u32).to_le_bytes());
let compressed_len = compress_into_sink_with_dict(
input,
&mut vec_sink_for_compression(&mut compressed, 4, 0, max_compressed_size),
ext_dict,
)
.unwrap();
compressed.truncate(4 + compressed_len);
compressed
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn read_u32_ptr(input: *const u8) -> u32 {
let mut num: u32 = 0;
unsafe {
core::ptr::copy_nonoverlapping(input, &mut num as *mut u32 as *mut u8, 4);
}
num
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn read_usize_ptr(input: *const u8) -> usize {
let mut num: usize = 0;
unsafe {
core::ptr::copy_nonoverlapping(
input,
&mut num as *mut usize as *mut u8,
core::mem::size_of::<usize>(),
);
}
num
}
#[inline]
#[cfg(not(feature = "safe-encode"))]
fn read_u16_ptr(input: *const u8) -> u16 {
let mut num: u16 = 0;
unsafe {
core::ptr::copy_nonoverlapping(input, &mut num as *mut u16 as *mut u8, 2);
}
num
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_count_same_bytes() {
let first: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
];
let second: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
];
assert_eq!(count_same_bytes(first, &mut 0, second, 0), 16);
let first: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0,
];
let second: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1,
];
assert_eq!(count_same_bytes(first, &mut 0, second, 0), 20);
let first: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 3, 4, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
];
let second: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 3, 4, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1,
];
assert_eq!(count_same_bytes(first, &mut 0, second, 0), 22);
let first: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 3, 4, 5, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0,
];
let second: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 3, 4, 5, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1,
];
assert_eq!(count_same_bytes(first, &mut 0, second, 0), 23);
let first: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 3, 4, 5, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0,
];
let second: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 3, 4, 6, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1,
];
assert_eq!(count_same_bytes(first, &mut 0, second, 0), 22);
let first: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 3, 9, 5, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0,
];
let second: &[u8] = &[
1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 3, 4, 6, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1,
];
assert_eq!(count_same_bytes(first, &mut 0, second, 0), 21);
for diff_idx in 0..100 {
let first: Vec<u8> = (0u8..255).cycle().take(100 + END_OFFSET).collect();
let mut second = first.clone();
second[diff_idx] = 255;
for start in 0..=diff_idx {
let same_bytes = count_same_bytes(&first, &mut start.clone(), &second, start);
assert_eq!(same_bytes, diff_idx - start);
}
}
}
#[test]
fn test_bug() {
let input: &[u8] = &[
10, 12, 14, 16, 18, 10, 12, 14, 16, 18, 10, 12, 14, 16, 18, 10, 12, 14, 16, 18,
];
let _out = compress(input);
}
#[test]
fn test_dict() {
let input: &[u8] = &[
10, 12, 14, 16, 18, 10, 12, 14, 16, 18, 10, 12, 14, 16, 18, 10, 12, 14, 16, 18,
];
let dict = input;
let compressed = compress_with_dict(input, dict);
assert_lt!(compressed.len(), compress(input).len());
assert!(compressed.len() < compress(input).len());
let mut uncompressed = vec![0u8; input.len()];
let uncomp_size = crate::block::decompress::decompress_into_with_dict(
&compressed,
&mut uncompressed,
dict,
)
.unwrap();
uncompressed.truncate(uncomp_size);
assert_eq!(input, uncompressed);
}
#[test]
fn test_dict_match_crossing() {
let input: &[u8] = &[
10, 12, 14, 16, 18, 10, 12, 14, 16, 18, 10, 12, 14, 16, 18, 10, 12, 14, 16, 18,
];
let dict = input;
let compressed = compress_with_dict(input, dict);
assert_lt!(compressed.len(), compress(input).len());
let mut uncompressed = vec![0u8; input.len() * 2];
let dict_cutoff = dict.len() / 2;
let output_start = dict.len() - dict_cutoff;
uncompressed[..output_start].copy_from_slice(&dict[dict_cutoff..]);
let uncomp_len = {
let mut sink = SliceSink::new(&mut uncompressed[..], output_start);
crate::block::decompress::decompress_internal::<_, true>(
&compressed,
&mut sink,
&dict[..dict_cutoff],
)
.unwrap()
};
assert_eq!(input.len(), uncomp_len);
assert_eq!(
input,
&uncompressed[output_start..output_start + uncomp_len]
);
}
#[test]
fn test_conformant_last_block() {
let aaas: &[u8] = b"aaaaaaaaaaaaaaa";
let out = compress(&aaas[..12]);
assert_gt!(out.len(), 12);
let out = compress(&aaas[..13]);
assert_le!(out.len(), 13);
let out = compress(&aaas[..14]);
assert_le!(out.len(), 14);
let out = compress(&aaas[..15]);
assert_le!(out.len(), 15);
let out = compress_with_dict(&aaas[..11], aaas);
assert_gt!(out.len(), 11);
let out = compress_with_dict(&aaas[..12], aaas);
assert_gt!(out.len(), 12);
let out = compress_with_dict(&aaas[..13], aaas);
assert_le!(out.len(), 13);
let out = compress_with_dict(&aaas[..14], aaas);
assert_le!(out.len(), 14);
let out = compress_with_dict(&aaas[..15], aaas);
assert_le!(out.len(), 15);
}
#[test]
fn test_dict_size() {
let dict = vec![b'a'; 1024 * 1024];
let input = &b"aaaaaaaaaaaaaaaaaaaaaaaaaaaaa"[..];
let compressed = compress_prepend_size_with_dict(input, &dict);
let decompressed =
crate::block::decompress_size_prepended_with_dict(&compressed, &dict).unwrap();
assert_eq!(decompressed, input);
}
}