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1 | //! Codebook support for bitstream reader. | |
2 | //! | |
3 | //! Codebook is a set of unique bit strings and values assigned to them. | |
4 | //! Since there are many ways to define codebook, this implementation employs [`CodebookDescReader`] trait to provide codebook generator with the codes. | |
5 | //! Please also pay attention to the codebook creation mode: if bitstream reader reads bits starting from most significant bit first then you should use [`MSB`] mode and [`LSB`] mode otherwise. | |
6 | //! | |
7 | //! # Examples | |
8 | //! | |
9 | //! Create a codebook from arrays with codeword descriptions: | |
10 | //! ``` | |
11 | //! use nihav_core::io::codebook::{ShortCodebookDesc, ShortCodebookDescReader, Codebook, CodebookMode}; | |
12 | //! | |
13 | //! let cb_desc: Vec<ShortCodebookDesc> = vec!( | |
14 | //! ShortCodebookDesc { code: 0b00, bits: 2 }, | |
15 | //! ShortCodebookDesc { code: 0, bits: 0 }, | |
16 | //! ShortCodebookDesc { code: 0b01, bits: 2 }, | |
17 | //! ShortCodebookDesc { code: 0b1, bits: 1 }); | |
18 | //! let mut cr = ShortCodebookDescReader::new(cb_desc); | |
19 | //! let cb = Codebook::new(&mut cr, CodebookMode::MSB).unwrap(); | |
20 | //! ``` | |
21 | //! | |
22 | //! Create a codebook using more flexible [`TableCodebookDescReader`] approach. | |
23 | //! This will create a codebook for the following set: `1` -> -2, `01` -> -1, `001` -> 0, `0001` -> 1, `00001` -> 2. | |
24 | //! ``` | |
25 | //! use nihav_core::io::codebook::{TableCodebookDescReader, Codebook, CodebookMode}; | |
26 | //! | |
27 | //! fn map_cb_index(index: usize) -> i16 { (index as i16) - 2 } | |
28 | //! const CB_BITS: [u8; 5] = [ 1, 2, 3, 4, 5 ]; | |
29 | //! const CB_CODES: [u8; 5] = [ 1, 1, 1, 1, 1 ]; | |
30 | //! | |
31 | //! let mut tcr = TableCodebookDescReader::new(&CB_CODES, &CB_BITS, map_cb_index); | |
32 | //! let cb = Codebook::new(&mut tcr, CodebookMode::MSB).unwrap(); | |
33 | //! ``` | |
34 | //! | |
35 | //! Read value using a codebook: | |
36 | //! ```no_run | |
37 | //! use nihav_core::io::bitreader::BitReader; | |
38 | //! use nihav_core::io::codebook::{Codebook, CodebookReader, CodebookMode}; | |
39 | //! # use nihav_core::io::codebook::{ShortCodebookDesc, ShortCodebookDescReader, CodebookDescReader, CodebookResult}; | |
40 | //! | |
41 | //! # fn foo(br: &mut BitReader) -> CodebookResult<()> { | |
42 | //! # let mut cr = ShortCodebookDescReader::new(vec![ShortCodebookDesc { code: 0b00, bits: 2 }]); | |
43 | //! let cb = Codebook::new(&mut cr, CodebookMode::MSB).unwrap(); | |
44 | //! let value = br.read_cb(&cb)?; | |
45 | //! # Ok(()) | |
46 | //! # } | |
47 | //! ``` | |
48 | //! | |
49 | //! [`MSB`]: ./enum.CodebookMode.html#variant.MSB | |
50 | //! [`LSB`]: ./enum.CodebookMode.html#variant.LSB | |
51 | //! [`CodebookDescReader`]: ./trait.CodebookDescReader.html | |
52 | //! [`TableCodebookDescReader`]: ./struct.TableCodebookDescReader.html | |
53 | ||
54 | use std::collections::HashMap; | |
55 | use std::cmp::{max, min}; | |
56 | use super::bitreader::BitReader; | |
57 | ||
58 | /// A list specifying general codebook operations errors. | |
59 | #[derive(Debug)] | |
60 | pub enum CodebookError { | |
61 | /// Codebook description contains errors. | |
62 | InvalidCodebook, | |
63 | /// Could not allocate memory for codebook. | |
64 | MemoryError, | |
65 | /// Bitstream contains a sequence not present in codebook. | |
66 | InvalidCode, | |
67 | } | |
68 | ||
69 | /// Codebook operation modes. | |
70 | #[derive(Debug, Copy, Clone)] | |
71 | pub enum CodebookMode { | |
72 | /// Codes in the codebook should be read most significant bit first. | |
73 | MSB, | |
74 | /// Codes in the codebook should be read least significant bit first. | |
75 | LSB, | |
76 | } | |
77 | ||
78 | /// A specialised `Result` type for codebook operations. | |
79 | pub type CodebookResult<T> = Result<T, CodebookError>; | |
80 | ||
81 | /// Codebook description for `(code bits, code length, code value)` triplet. | |
82 | /// | |
83 | /// This should be used to create a list of codeword definitions for [`FullCodebookDescReader`]. | |
84 | /// | |
85 | /// [`FullCodebookDescReader`]: ./struct.FullCodebookDescReader.html | |
86 | #[derive(Clone,Copy)] | |
87 | pub struct FullCodebookDesc<S> { | |
88 | /// Codeword bits. | |
89 | pub code: u32, | |
90 | /// Codeword length. | |
91 | pub bits: u8, | |
92 | /// Codeword value (symbol). | |
93 | pub sym: S, | |
94 | } | |
95 | ||
96 | /// Codebook description for `(code bits, code length)` pair with array index being used as codeword value. | |
97 | /// | |
98 | /// This should be used to create a list of codeword definitions for [`ShortCodebookDescReader`]. | |
99 | /// | |
100 | /// [`ShortCodebookDescReader`]: ./struct.ShortCodebookDescReader.html | |
101 | #[derive(Clone,Copy)] | |
102 | pub struct ShortCodebookDesc { | |
103 | /// Codeword bits. | |
104 | pub code: u32, | |
105 | /// Codeword length. | |
106 | pub bits: u8, | |
107 | } | |
108 | ||
109 | /// The interface for providing a list of codeword definitions to the codebook creator. | |
110 | /// | |
111 | /// The structure implementing this trait should be able to provide the total number of defined codewords and their bits and values. [`ShortCodebookDescReader`] or [`TableCodebookDescReader`] are some examples of such implementation. | |
112 | /// Codeword definitions with zero length are ignored (those may be used to create sparse codebook definitions though). | |
113 | /// | |
114 | /// [`ShortCodebookDescReader`]: ./struct.ShortCodebookDescReader.html | |
115 | /// [`TableCodebookDescReader`]: ./struct.TableCodebookDescReader.html | |
116 | #[allow(clippy::len_without_is_empty)] | |
117 | pub trait CodebookDescReader<S> { | |
118 | /// Returns the codeword length for the provided index. | |
119 | fn bits(&mut self, idx: usize) -> u8; | |
120 | /// Returns the codeword bits for the provided index. | |
121 | fn code(&mut self, idx: usize) -> u32; | |
122 | /// Returns the codeword value (aka codeword symbol) for the provided index. | |
123 | fn sym (&mut self, idx: usize) -> S; | |
124 | /// Returns the total number of defined codewords. | |
125 | fn len (&mut self) -> usize; | |
126 | } | |
127 | ||
128 | /// The codebook structure for code reading. | |
129 | #[allow(dead_code)] | |
130 | pub struct Codebook<S> { | |
131 | pub table: Vec<u32>, | |
132 | pub syms: Vec<S>, | |
133 | pub lut_bits: u8, | |
134 | } | |
135 | ||
136 | /// Trait allowing bitreader to use codebook for decoding bit sequences. | |
137 | pub trait CodebookReader<S> { | |
138 | /// Reads the codeword from the bitstream and returns its value (or [`InvalidCode`] on error). | |
139 | /// | |
140 | /// [`InvalidCode`]: ./enum.CodebookError.html#variant.InvalidCode | |
141 | fn read_cb(&mut self, cb: &Codebook<S>) -> CodebookResult<S>; | |
142 | } | |
143 | ||
144 | pub const TABLE_FILL_VALUE: u32 = 0x7F; | |
145 | const MAX_LUT_BITS: u8 = 10; | |
146 | ||
147 | fn fill_lut_msb(table: &mut Vec<u32>, off: usize, | |
148 | code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) -> CodebookResult<()> { | |
149 | if !esc { | |
150 | let fill_len = lut_bits - bits; | |
151 | let fill_size = 1 << fill_len; | |
152 | let fill_code = code << (lut_bits - bits); | |
153 | let lut_value = (symidx << 8) | u32::from(bits); | |
154 | for j in 0..fill_size { | |
155 | let idx = (fill_code + j) as usize; | |
156 | if table[idx + off] != TABLE_FILL_VALUE { return Err(CodebookError::InvalidCodebook); } | |
157 | table[idx + off] = lut_value; | |
158 | } | |
159 | } else { | |
160 | let idx = (code as usize) + off; | |
161 | if table[idx] != TABLE_FILL_VALUE { return Err(CodebookError::InvalidCodebook); } | |
162 | table[idx] = (symidx << 8) | 0x80 | u32::from(bits); | |
163 | } | |
164 | Ok(()) | |
165 | } | |
166 | ||
167 | fn fill_lut_lsb(table: &mut Vec<u32>, off: usize, | |
168 | code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) -> CodebookResult<()> { | |
169 | if !esc { | |
170 | let fill_len = lut_bits - bits; | |
171 | let fill_size = 1 << fill_len; | |
172 | let fill_code = code; | |
173 | let step = lut_bits - fill_len; | |
174 | for j in 0..fill_size { | |
175 | let idx = (fill_code + (j << step)) as usize; | |
176 | if table[idx + off] != TABLE_FILL_VALUE { return Err(CodebookError::InvalidCodebook); } | |
177 | table[idx + off] = (symidx << 8) | u32::from(bits); | |
178 | } | |
179 | } else { | |
180 | let idx = (code as usize) + off; | |
181 | if table[idx] != TABLE_FILL_VALUE { return Err(CodebookError::InvalidCodebook); } | |
182 | table[idx] = (symidx << 8) | 0x80 | u32::from(bits); | |
183 | } | |
184 | Ok(()) | |
185 | } | |
186 | ||
187 | fn fill_lut(table: &mut Vec<u32>, mode: CodebookMode, | |
188 | off: usize, code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) -> CodebookResult<bool> { | |
189 | match mode { | |
190 | CodebookMode::MSB => fill_lut_msb(table, off, code, bits, lut_bits, symidx, esc)?, | |
191 | CodebookMode::LSB => fill_lut_lsb(table, off, code, bits, lut_bits, symidx, esc)?, | |
192 | }; | |
193 | Ok(bits > lut_bits) | |
194 | } | |
195 | ||
196 | fn resize_table(table: &mut Vec<u32>, bits: u8) -> CodebookResult<u32> { | |
197 | let add_size = (1 << bits) as usize; | |
198 | table.reserve(add_size); | |
199 | let cur_off = table.len() as u32; | |
200 | let new_size = table.len() + add_size; | |
201 | if table.capacity() < new_size { return Err(CodebookError::MemoryError); } | |
202 | table.resize(new_size, TABLE_FILL_VALUE); | |
203 | Ok(cur_off) | |
204 | } | |
205 | ||
206 | ||
207 | fn extract_lut_part(code: u32, bits: u8, lut_bits: u8, mode: CodebookMode) -> u32 { | |
208 | match mode { | |
209 | CodebookMode::MSB => code >> (bits - lut_bits), | |
210 | CodebookMode::LSB => code & ((1 << lut_bits) - 1), | |
211 | } | |
212 | } | |
213 | ||
214 | fn extract_esc_part(code: u32, bits: u8, lut_bits: u8, mode: CodebookMode) -> u32 { | |
215 | match mode { | |
216 | CodebookMode::MSB => code & ((1 << (bits - lut_bits)) - 1), | |
217 | CodebookMode::LSB => code >> lut_bits, | |
218 | } | |
219 | } | |
220 | ||
221 | #[derive(Clone,Copy)] | |
222 | struct Code { | |
223 | code: u32, | |
224 | bits: u8, | |
225 | idx: usize, | |
226 | } | |
227 | ||
228 | struct CodeBucket { | |
229 | maxlen: u8, | |
230 | offset: usize, | |
231 | codes: Vec<Code>, | |
232 | } | |
233 | ||
234 | impl CodeBucket { | |
235 | fn new() -> Self { | |
236 | CodeBucket { maxlen: 0, offset: 0, codes: Vec::new() } | |
237 | } | |
238 | fn add_code(&mut self, c: Code) { | |
239 | if c.bits > self.maxlen { self.maxlen = c.bits; } | |
240 | self.codes.push(c); | |
241 | } | |
242 | } | |
243 | ||
244 | type EscapeCodes = HashMap<u32, CodeBucket>; | |
245 | ||
246 | fn add_esc_code(cc: &mut EscapeCodes, key: u32, code: u32, bits: u8, idx: usize) { | |
247 | cc.entry(key).or_insert_with(CodeBucket::new); | |
248 | let b = cc.get_mut(&key); | |
249 | if let Some(bucket) = b { | |
250 | bucket.add_code(Code {code, bits, idx }); | |
251 | } else { panic!("no bucket when expected!"); } | |
252 | } | |
253 | ||
254 | fn build_esc_lut(table: &mut Vec<u32>, | |
255 | mode: CodebookMode, | |
256 | bucket: &CodeBucket) -> CodebookResult<()> { | |
257 | let mut escape_list: EscapeCodes = HashMap::new(); | |
258 | let maxlen = if bucket.maxlen > MAX_LUT_BITS { MAX_LUT_BITS } else { bucket.maxlen }; | |
259 | ||
260 | for code in &bucket.codes { | |
261 | let bits = code.bits; | |
262 | if code.bits <= MAX_LUT_BITS { | |
263 | fill_lut(table, mode, bucket.offset, code.code, bits, | |
264 | maxlen, code.idx as u32, false)?; | |
265 | } else { | |
266 | let ckey = extract_lut_part(code.code, bits, MAX_LUT_BITS, mode); | |
267 | let cval = extract_esc_part(code.code, bits, MAX_LUT_BITS, mode); | |
268 | add_esc_code(&mut escape_list, ckey, cval, bits - MAX_LUT_BITS, code.idx); | |
269 | } | |
270 | } | |
271 | ||
272 | let cur_offset = bucket.offset; | |
273 | for (ckey, sec_bucket) in &mut escape_list { | |
274 | let key = *ckey as u32; | |
275 | let maxlen = min(sec_bucket.maxlen, MAX_LUT_BITS); | |
276 | let new_off = resize_table(table, maxlen)?; | |
277 | fill_lut(table, mode, cur_offset, key, maxlen, | |
278 | MAX_LUT_BITS, new_off, true)?; | |
279 | sec_bucket.offset = new_off as usize; | |
280 | } | |
281 | ||
282 | for sec_bucket in escape_list.values() { | |
283 | build_esc_lut(table, mode, sec_bucket)?; | |
284 | } | |
285 | ||
286 | Ok(()) | |
287 | } | |
288 | ||
289 | impl<S: Copy> Codebook<S> { | |
290 | ||
291 | /// Constructs a new `Codebook` instance using provided codebook description and mode. | |
292 | pub fn new(cb: &mut CodebookDescReader<S>, mode: CodebookMode) -> CodebookResult<Self> { | |
293 | let mut maxbits = 0; | |
294 | let mut nnz = 0; | |
295 | let mut escape_list: EscapeCodes = HashMap::new(); | |
296 | ||
297 | let mut symidx: usize = 0; | |
298 | for i in 0..cb.len() { | |
299 | let bits = cb.bits(i); | |
300 | if bits > 0 { | |
301 | nnz += 1; | |
302 | if cb.code(i) >= (1 << bits) { | |
303 | return Err(CodebookError::InvalidCodebook); | |
304 | } | |
305 | } | |
306 | maxbits = max(bits, maxbits); | |
307 | if bits > MAX_LUT_BITS { | |
308 | let code = cb.code(i); | |
309 | let ckey = extract_lut_part(code, bits, MAX_LUT_BITS, mode); | |
310 | let cval = extract_esc_part(code, bits, MAX_LUT_BITS, mode); | |
311 | add_esc_code(&mut escape_list, ckey, cval, bits - MAX_LUT_BITS, symidx); | |
312 | } | |
313 | if bits > 0 { symidx += 1; } | |
314 | } | |
315 | if maxbits == 0 { return Err(CodebookError::InvalidCodebook); } | |
316 | ||
317 | if maxbits > MAX_LUT_BITS { maxbits = MAX_LUT_BITS; } | |
318 | ||
319 | let tab_len = 1 << maxbits; | |
320 | let mut table: Vec<u32> = Vec::with_capacity(tab_len); | |
321 | let mut syms: Vec<S> = Vec::with_capacity(nnz); | |
322 | if table.capacity() < tab_len { return Err(CodebookError::MemoryError); } | |
323 | if syms.capacity() < nnz { return Err(CodebookError::MemoryError); } | |
324 | table.resize(tab_len, TABLE_FILL_VALUE); | |
325 | ||
326 | let mut symidx: u32 = 0; | |
327 | for i in 0..cb.len() { | |
328 | let bits = cb.bits(i); | |
329 | let code = cb.code(i); | |
330 | if bits == 0 { continue; } | |
331 | if bits <= MAX_LUT_BITS { | |
332 | fill_lut(&mut table, mode, 0, code, bits, maxbits, symidx, false)?; | |
333 | } else { | |
334 | let ckey = extract_lut_part(code, bits, MAX_LUT_BITS, mode) as usize; | |
335 | if table[ckey] == TABLE_FILL_VALUE { | |
336 | let key = ckey as u32; | |
337 | if let Some(bucket) = escape_list.get_mut(&key) { | |
338 | let maxlen = min(bucket.maxlen, MAX_LUT_BITS); | |
339 | let new_off = resize_table(&mut table, maxlen)?; | |
340 | fill_lut(&mut table, mode, 0, key, maxlen, MAX_LUT_BITS, new_off, true)?; | |
341 | bucket.offset = new_off as usize; | |
342 | } | |
343 | } | |
344 | } | |
345 | symidx += 1; | |
346 | } | |
347 | ||
348 | for bucket in escape_list.values() { | |
349 | build_esc_lut(&mut table, mode, &bucket)?; | |
350 | } | |
351 | ||
352 | for i in 0..cb.len() { | |
353 | if cb.bits(i) > 0 { | |
354 | syms.push(cb.sym(i)); | |
355 | } | |
356 | } | |
357 | ||
358 | Ok(Codebook { table, syms, lut_bits: maxbits }) | |
359 | } | |
360 | } | |
361 | ||
362 | impl<'a, S: Copy> CodebookReader<S> for BitReader<'a> { | |
363 | #[allow(unused_variables)] | |
364 | fn read_cb(&mut self, cb: &Codebook<S>) -> CodebookResult<S> { | |
365 | let mut esc = true; | |
366 | let mut idx = 0; | |
367 | let mut lut_bits = cb.lut_bits; | |
368 | while esc { | |
369 | let lut_idx = (self.peek(lut_bits) as usize) + (idx as usize); | |
370 | if cb.table[lut_idx] == TABLE_FILL_VALUE { return Err(CodebookError::InvalidCode); } | |
371 | let bits = cb.table[lut_idx] & 0x7F; | |
372 | esc = (cb.table[lut_idx] & 0x80) != 0; | |
373 | idx = (cb.table[lut_idx] >> 8) as usize; | |
374 | let skip_bits = if esc { u32::from(lut_bits) } else { bits }; | |
375 | if (skip_bits as isize) > self.left() { | |
376 | return Err(CodebookError::InvalidCode); | |
377 | } | |
378 | self.skip(skip_bits as u32).unwrap(); | |
379 | lut_bits = bits as u8; | |
380 | } | |
381 | Ok(cb.syms[idx]) | |
382 | } | |
383 | } | |
384 | ||
385 | /// Codebook description that stores a list of codewords and their values. | |
386 | pub struct FullCodebookDescReader<S> { | |
387 | data: Vec<FullCodebookDesc<S>>, | |
388 | } | |
389 | ||
390 | impl<S> FullCodebookDescReader<S> { | |
391 | /// Constructs a new `FullCodebookDescReader` instance. | |
392 | pub fn new(data: Vec<FullCodebookDesc<S>>) -> Self { | |
393 | FullCodebookDescReader { data } | |
394 | } | |
395 | } | |
396 | ||
397 | impl<S: Copy> CodebookDescReader<S> for FullCodebookDescReader<S> { | |
398 | fn bits(&mut self, idx: usize) -> u8 { self.data[idx].bits } | |
399 | fn code(&mut self, idx: usize) -> u32 { self.data[idx].code } | |
400 | fn sym (&mut self, idx: usize) -> S { self.data[idx].sym } | |
401 | fn len(&mut self) -> usize { self.data.len() } | |
402 | } | |
403 | ||
404 | /// Codebook description that stores a list of codewords and their value is equal to the index. | |
405 | pub struct ShortCodebookDescReader { | |
406 | data: Vec<ShortCodebookDesc>, | |
407 | } | |
408 | ||
409 | impl ShortCodebookDescReader { | |
410 | /// Constructs a new `ShortCodebookDescReader` instance. | |
411 | pub fn new(data: Vec<ShortCodebookDesc<>>) -> Self { | |
412 | ShortCodebookDescReader { data } | |
413 | } | |
414 | } | |
415 | ||
416 | impl CodebookDescReader<u32> for ShortCodebookDescReader { | |
417 | fn bits(&mut self, idx: usize) -> u8 { self.data[idx].bits } | |
418 | fn code(&mut self, idx: usize) -> u32 { self.data[idx].code } | |
419 | fn sym (&mut self, idx: usize) -> u32 { idx as u32 } | |
420 | fn len(&mut self) -> usize { self.data.len() } | |
421 | } | |
422 | ||
423 | /// Flexible codebook description that uses two separate arrays for codeword bits and lengths and a function that maps codeword index into its symbol. | |
424 | pub struct TableCodebookDescReader<'a, CodeType:'static, IndexType:'static> { | |
425 | bits: &'a [u8], | |
426 | codes: &'a [CodeType], | |
427 | idx_map: fn(usize) -> IndexType, | |
428 | } | |
429 | ||
430 | impl<'a, CodeType, IndexType> TableCodebookDescReader<'a, CodeType, IndexType> { | |
431 | /// Constructs a new `TableCodebookDescReader` instance. | |
432 | pub fn new(codes: &'a [CodeType], bits: &'a [u8], idx_map: fn(usize) -> IndexType) -> Self { | |
433 | Self { bits, codes, idx_map } | |
434 | } | |
435 | } | |
436 | impl<'a, CodeType: Copy+Into<u32>, IndexType> CodebookDescReader<IndexType> for TableCodebookDescReader<'a, CodeType, IndexType> | |
437 | { | |
438 | fn bits(&mut self, idx: usize) -> u8 { self.bits[idx] } | |
439 | fn code(&mut self, idx: usize) -> u32 { self.codes[idx].into() } | |
440 | fn sym (&mut self, idx: usize) -> IndexType { (self.idx_map)(idx) } | |
441 | fn len(&mut self) -> usize { self.bits.len() } | |
442 | } | |
443 | ||
444 | #[cfg(test)] | |
445 | mod test { | |
446 | use super::*; | |
447 | use crate::io::bitreader::*; | |
448 | ||
449 | #[test] | |
450 | fn test_cb() { | |
451 | const BITS: [u8; 2] = [0b01011011, 0b10111100]; | |
452 | let cb_desc: Vec<FullCodebookDesc<i8>> = vec!( | |
453 | FullCodebookDesc { code: 0b0, bits: 1, sym: 16 }, | |
454 | FullCodebookDesc { code: 0b10, bits: 2, sym: -3 }, | |
455 | FullCodebookDesc { code: 0b110, bits: 3, sym: 42 }, | |
456 | FullCodebookDesc { code: 0b1110, bits: 4, sym: -42 } | |
457 | ); | |
458 | let buf = &BITS; | |
459 | let mut br = BitReader::new(buf, BitReaderMode::BE); | |
460 | let mut cfr = FullCodebookDescReader::new(cb_desc); | |
461 | let cb = Codebook::new(&mut cfr, CodebookMode::MSB).unwrap(); | |
462 | assert_eq!(br.read_cb(&cb).unwrap(), 16); | |
463 | assert_eq!(br.read_cb(&cb).unwrap(), -3); | |
464 | assert_eq!(br.read_cb(&cb).unwrap(), 42); | |
465 | assert_eq!(br.read_cb(&cb).unwrap(), -42); | |
466 | let ret = br.read_cb(&cb); | |
467 | if let Err(e) = ret { | |
468 | assert_eq!(e as i32, CodebookError::InvalidCode as i32); | |
469 | } else { | |
470 | assert_eq!(0, 1); | |
471 | } | |
472 | ||
473 | let scb_desc: Vec<ShortCodebookDesc> = vec!( | |
474 | ShortCodebookDesc { code: 0b0, bits: 1 }, | |
475 | ShortCodebookDesc { code: 0, bits: 0 }, | |
476 | ShortCodebookDesc { code: 0b10, bits: 2 }, | |
477 | ShortCodebookDesc { code: 0, bits: 0 }, | |
478 | ShortCodebookDesc { code: 0, bits: 0 }, | |
479 | ShortCodebookDesc { code: 0b110, bits: 3 }, | |
480 | ShortCodebookDesc { code: 0, bits: 0 }, | |
481 | ShortCodebookDesc { code: 0b11100, bits: 5 }, | |
482 | ShortCodebookDesc { code: 0b11101, bits: 5 }, | |
483 | ShortCodebookDesc { code: 0b1111010, bits: 7 }, | |
484 | ShortCodebookDesc { code: 0b1111011, bits: 7 }, | |
485 | ShortCodebookDesc { code: 0b1111110, bits: 7 }, | |
486 | ShortCodebookDesc { code: 0b11111111, bits: 8 } | |
487 | ); | |
488 | let mut br2 = BitReader::new(buf, BitReaderMode::BE); | |
489 | let mut cfr = ShortCodebookDescReader::new(scb_desc); | |
490 | let cb = Codebook::new(&mut cfr, CodebookMode::MSB).unwrap(); | |
491 | assert_eq!(br2.read_cb(&cb).unwrap(), 0); | |
492 | assert_eq!(br2.read_cb(&cb).unwrap(), 2); | |
493 | assert_eq!(br2.read_cb(&cb).unwrap(), 5); | |
494 | assert_eq!(br2.read_cb(&cb).unwrap(), 8); | |
495 | ||
496 | assert_eq!(reverse_bits(0b0000_0101_1011_1011_1101_1111_0111_1111, 32), | |
497 | 0b1111_1110_1111_1011_1101_1101_1010_0000); | |
498 | ||
499 | const BITS_LE: [u8; 3] = [0b11101111, 0b01110010, 0b01]; | |
500 | let buf = &BITS_LE; | |
501 | let scble_desc: Vec<ShortCodebookDesc> = vec!( | |
502 | ShortCodebookDesc { code: 0b00, bits: 2 }, | |
503 | ShortCodebookDesc { code: 0, bits: 0 }, | |
504 | ShortCodebookDesc { code: 0b01, bits: 2 }, | |
505 | ShortCodebookDesc { code: 0, bits: 0 }, | |
506 | ShortCodebookDesc { code: 0, bits: 0 }, | |
507 | ShortCodebookDesc { code: 0b011, bits: 3 }, | |
508 | ShortCodebookDesc { code: 0, bits: 0 }, | |
509 | ShortCodebookDesc { code: 0b10111, bits: 5 }, | |
510 | ShortCodebookDesc { code: 0b00111, bits: 5 }, | |
511 | ShortCodebookDesc { code: 0b0101111, bits: 7 }, | |
512 | ShortCodebookDesc { code: 0b0111111, bits: 7 }, | |
513 | ShortCodebookDesc { code: 0b1011101111, bits: 10 } | |
514 | ); | |
515 | let mut brl = BitReader::new(buf, BitReaderMode::LE); | |
516 | let mut cfr = ShortCodebookDescReader::new(scble_desc); | |
517 | let cb = Codebook::new(&mut cfr, CodebookMode::LSB).unwrap(); | |
518 | assert_eq!(brl.read_cb(&cb).unwrap(), 11); | |
519 | assert_eq!(brl.read_cb(&cb).unwrap(), 0); | |
520 | assert_eq!(brl.read_cb(&cb).unwrap(), 7); | |
521 | assert_eq!(brl.read_cb(&cb).unwrap(), 0); | |
522 | } | |
523 | } |