use alloc::vec::Vec;
#[derive(Copy, Clone, Debug)]
pub enum CodingClass {
Dc = 0,
Ac = 1,
}
static DEFAULT_LUMA_DC_CODE_LENGTHS: [u8; 16] = [
0x00, 0x01, 0x05, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
];
static DEFAULT_LUMA_DC_VALUES: [u8; 12] = [
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B,
];
static DEFAULT_CHROMA_DC_CODE_LENGTHS: [u8; 16] = [
0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
];
static DEFAULT_CHROMA_DC_VALUES: [u8; 12] = [
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B,
];
static DEFAULT_LUMA_AC_CODE_LENGTHS: [u8; 16] = [
0x00, 0x02, 0x01, 0x03, 0x03, 0x02, 0x04, 0x03, 0x05, 0x05, 0x04, 0x04, 0x00, 0x00, 0x01, 0x7D,
];
static DEFAULT_LUMA_AC_VALUES: [u8; 162] = [
0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xA1, 0x08, 0x23, 0x42, 0xB1, 0xC1, 0x15, 0x52, 0xD1, 0xF0,
0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0A, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28,
0x29, 0x2A, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7,
0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5,
0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xE1, 0xE2,
0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,
0xF9, 0xFA,
];
static DEFAULT_CHROMA_AC_CODE_LENGTHS: [u8; 16] = [
0x00, 0x02, 0x01, 0x02, 0x04, 0x04, 0x03, 0x04, 0x07, 0x05, 0x04, 0x04, 0x00, 0x01, 0x02, 0x77,
];
static DEFAULT_CHROMA_AC_VALUES: [u8; 162] = [
0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xA1, 0xB1, 0xC1, 0x09, 0x23, 0x33, 0x52, 0xF0,
0x15, 0x62, 0x72, 0xD1, 0x0A, 0x16, 0x24, 0x34, 0xE1, 0x25, 0xF1, 0x17, 0x18, 0x19, 0x1A, 0x26,
0x27, 0x28, 0x29, 0x2A, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
0x69, 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5,
0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3,
0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA,
0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,
0xF9, 0xFA,
];
pub struct HuffmanTable {
lookup_table: [(u8, u16); 256],
length: [u8; 16],
values: Vec<u8>,
}
impl HuffmanTable {
pub fn new(length: &[u8; 16], values: &[u8]) -> HuffmanTable {
HuffmanTable {
lookup_table: create_lookup_table(length, values),
length: *length,
values: values.to_vec(),
}
}
pub fn default_luma_dc() -> HuffmanTable {
Self::new(&DEFAULT_LUMA_DC_CODE_LENGTHS, &DEFAULT_LUMA_DC_VALUES)
}
pub fn default_luma_ac() -> HuffmanTable {
Self::new(&DEFAULT_LUMA_AC_CODE_LENGTHS, &DEFAULT_LUMA_AC_VALUES)
}
pub fn default_chroma_dc() -> HuffmanTable {
Self::new(&DEFAULT_CHROMA_DC_CODE_LENGTHS, &DEFAULT_CHROMA_DC_VALUES)
}
pub fn default_chroma_ac() -> HuffmanTable {
Self::new(&DEFAULT_CHROMA_AC_CODE_LENGTHS, &DEFAULT_CHROMA_AC_VALUES)
}
#[allow(clippy::needless_range_loop)]
pub fn new_optimized(mut freq: [u32; 257]) -> HuffmanTable {
let mut others = [-1i32; 257];
let mut codesize = [0usize; 257];
loop {
let mut v1 = None;
let mut v1_min = u32::MAX;
for (i, &f) in freq.iter().enumerate() {
if f > 0 && f <= v1_min {
v1_min = f;
v1 = Some(i);
}
}
let mut v1 = match v1 {
Some(v) => v,
None => break,
};
let mut v2 = None;
let mut v2_min = u32::MAX;
for (i, &f) in freq.iter().enumerate() {
if f > 0 && f <= v2_min && i != v1 {
v2_min = f;
v2 = Some(i);
}
}
let mut v2 = match v2 {
Some(v) => v,
None => break,
};
freq[v1] += freq[v2];
freq[v2] = 0;
codesize[v1] += 1;
while others[v1] >= 0 {
v1 = others[v1] as usize;
codesize[v1] += 1;
}
others[v1] = v2 as i32;
codesize[v2] += 1;
while others[v2] >= 0 {
v2 = others[v2] as usize;
codesize[v2] += 1;
}
}
let mut bits = [0u8; 33];
for &size in codesize.iter() {
if size > 0 {
bits[size] += 1;
}
}
let mut i = 32;
while i > 16 {
while bits[i] > 0 {
let mut j = i - 2;
while bits[j] == 0 {
j -= 1;
}
bits[i] -= 2;
bits[i - 1] += 1;
bits[j + 1] += 2;
bits[j] -= 1;
}
i -= 1;
}
while bits[i] == 0 {
debug_assert!(i > 0, "Error creating codesizes for frequency {:?}", freq);
i -= 1;
}
bits[i] -= 1;
let mut huffval = [0u8; 256];
let mut k = 0;
for i in 1..=32 {
for j in 0..=255 {
if codesize[j] == i {
huffval[k] = j as u8;
k += 1;
}
}
}
let mut length = [0u8; 16];
for (i, v) in length.iter_mut().enumerate() {
*v = bits[i + 1];
}
let values = huffval[0..k].to_vec();
HuffmanTable {
lookup_table: create_lookup_table(&length, &values),
length,
values,
}
}
#[inline]
pub fn get_for_value(&self, value: u8) -> &(u8, u16) {
let res = &self.lookup_table[value as usize];
debug_assert!(res.0 > 0, "Got zero size code for value: {}", value);
res
}
pub fn length(&self) -> &[u8; 16] {
&self.length
}
pub fn values(&self) -> &[u8] {
&self.values
}
}
fn create_sizes(code_lengths: &[u8; 16]) -> [u8; 256] {
let mut sizes = [0u8; 256];
let mut k = 0;
for (i, &length) in code_lengths.iter().enumerate() {
for _ in 0..length {
sizes[k] = (i + 1) as u8;
k += 1;
}
}
sizes
}
fn create_codes(sizes: &[u8; 256]) -> [u16; 256] {
let mut codes = [0u16; 256];
let mut current_code = 0;
let mut current_size = sizes[0];
for (&size, code) in sizes.iter().take_while(|s| **s != 0).zip(codes.iter_mut()) {
if current_size != size {
let size_diff = size - current_size;
current_code <<= size_diff as usize;
current_size = size;
}
*code = current_code;
current_code += 1;
}
codes
}
fn create_lookup_table(code_length: &[u8; 16], values: &[u8]) -> [(u8, u16); 256] {
let sizes = create_sizes(code_length);
let codes = create_codes(&sizes);
let mut lookup_table = [(0u8, 0u16); 256];
for (i, &value) in values.iter().enumerate() {
lookup_table[value as usize] = (sizes[i], codes[i]);
}
lookup_table
}