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id="612">612</span> <span id="613">613</span> <span id="614">614</span> <span id="615">615</span> <span id="616">616</span> <span id="617">617</span> <span id="618">618</span> <span id="619">619</span> <span id="620">620</span> <span id="621">621</span> <span id="622">622</span> <span id="623">623</span> <span id="624">624</span> <span id="625">625</span> <span id="626">626</span> <span id="627">627</span> <span id="628">628</span> <span id="629">629</span> <span id="630">630</span> <span id="631">631</span> <span id="632">632</span> <span id="633">633</span> <span id="634">634</span> <span id="635">635</span> <span id="636">636</span> <span id="637">637</span> <span id="638">638</span> <span id="639">639</span> <span id="640">640</span> <span id="641">641</span> <span id="642">642</span> <span id="643">643</span> <span id="644">644</span> <span id="645">645</span> <span id="646">646</span> <span id="647">647</span> <span id="648">648</span> <span id="649">649</span> <span id="650">650</span> <span id="651">651</span> <span id="652">652</span> <span id="653">653</span> <span id="654">654</span> <span id="655">655</span> <span id="656">656</span> <span id="657">657</span> <span id="658">658</span> <span id="659">659</span> <span id="660">660</span> <span id="661">661</span> <span id="662">662</span> <span id="663">663</span> <span id="664">664</span> <span id="665">665</span> <span id="666">666</span> <span id="667">667</span> <span id="668">668</span> <span id="669">669</span> <span id="670">670</span> <span id="671">671</span> <span id="672">672</span> <span id="673">673</span> <span id="674">674</span> <span id="675">675</span> <span id="676">676</span> <span id="677">677</span> <span id="678">678</span> <span id="679">679</span> <span id="680">680</span> <span id="681">681</span> <span id="682">682</span> <span id="683">683</span> <span id="684">684</span> <span id="685">685</span> <span id="686">686</span> <span id="687">687</span> <span id="688">688</span> <span id="689">689</span> <span id="690">690</span> <span id="691">691</span> <span id="692">692</span> <span id="693">693</span> <span id="694">694</span> <span id="695">695</span> <span id="696">696</span> <span id="697">697</span> <span id="698">698</span> <span id="699">699</span> <span id="700">700</span> <span id="701">701</span> <span id="702">702</span> </pre><pre class='rust '> <span class='doccomment'>//! A module exposing utilities for encoding and decoding Huffman-coded octet</span> <span class='doccomment'>//! strings, under the Huffman code defined by HPACK.</span> <span class='doccomment'>//! (HPACK-draft-10, Appendix B)</span> <span class='kw'>use</span> <span class='ident'>std</span>::<span class='ident'>collections</span>::<span class='ident'>HashMap</span>; <span class='doccomment'>/// Represents a symbol that can be inserted into a Huffman-encoded octet</span> <span class='doccomment'>/// string.</span> <span class='kw'>enum</span> <span class='ident'>HuffmanCodeSymbol</span> { <span class='doccomment'>/// Any octet is a valid symbol</span> <span class='ident'>Symbol</span>(<span class='ident'>u8</span>), <span class='doccomment'>/// A special symbol represents the end of the string</span> <span class='ident'>EndOfString</span>, } <span class='kw'>impl</span> <span class='ident'>HuffmanCodeSymbol</span> { <span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>new</span>(<span class='ident'>symbol</span>: <span class='ident'>usize</span>) <span class='op'>-></span> <span class='ident'>HuffmanCodeSymbol</span> { <span class='kw'>if</span> <span class='ident'>symbol</span> <span class='op'>==</span> <span class='number'>256</span> { <span class='ident'>HuffmanCodeSymbol</span>::<span class='ident'>EndOfString</span> } <span class='kw'>else</span> { <span class='comment'>// It is safe to downcast since now we know that the value</span> <span class='comment'>// is in the half-open interval [0, 256)</span> <span class='ident'>HuffmanCodeSymbol</span>::<span class='ident'>Symbol</span>(<span class='ident'>symbol</span> <span class='kw'>as</span> <span class='ident'>u8</span>) } } } <span class='doccomment'>/// Represents the error variants that the `HuffmanDecoder` can return.</span> <span class='attribute'>#[<span class='ident'>derive</span>(<span class='ident'>PartialEq</span>)]</span> <span class='attribute'>#[<span class='ident'>derive</span>(<span class='ident'>Copy</span>)]</span> <span class='attribute'>#[<span class='ident'>derive</span>(<span class='ident'>Clone</span>)]</span> <span class='attribute'>#[<span class='ident'>derive</span>(<span class='ident'>Debug</span>)]</span> <span class='kw'>pub</span> <span class='kw'>enum</span> <span class='ident'>HuffmanDecoderError</span> { <span class='doccomment'>/// Any padding strictly larger than 7 bits MUST be interpreted as an error</span> <span class='ident'>PaddingTooLarge</span>, <span class='doccomment'>/// Any padding that does not correspond to the most significant bits of</span> <span class='doccomment'>/// EOS MUST be interpreted as an error.</span> <span class='ident'>InvalidPadding</span>, <span class='doccomment'>/// If EOS is ever found in the string, it causes an error.</span> <span class='ident'>EOSInString</span>, } <span class='doccomment'>/// The type that represents the result of the `decode` method of the</span> <span class='doccomment'>/// `HuffmanDecoder`.</span> <span class='kw'>pub</span> <span class='kw'>type</span> <span class='ident'>HuffmanDecoderResult</span> <span class='op'>=</span> <span class='prelude-ty'>Result</span><span class='op'><</span><span class='ident'>Vec</span><span class='op'><</span><span class='ident'>u8</span><span class='op'>></span>, <span class='ident'>HuffmanDecoderError</span><span class='op'>></span>; <span class='doccomment'>/// A simple implementation of a Huffman code decoder.</span> <span class='kw'>pub</span> <span class='kw'>struct</span> <span class='ident'>HuffmanDecoder</span> { <span class='ident'>table</span>: <span class='ident'>HashMap</span><span class='op'><</span><span class='ident'>u8</span>, <span class='ident'>HashMap</span><span class='op'><</span><span class='ident'>u32</span>, <span class='ident'>HuffmanCodeSymbol</span><span class='op'>>></span>, <span class='comment'>// The representation of the EOS: the left-aligned code representation and</span> <span class='comment'>// the actual length of the codepoint, as a tuple.</span> <span class='ident'>eos_codepoint</span>: (<span class='ident'>u32</span>, <span class='ident'>u8</span>), } <span class='kw'>impl</span> <span class='ident'>HuffmanDecoder</span> { <span class='doccomment'>/// Constructs a new `HuffmanDecoder` using the given table of</span> <span class='doccomment'>/// (code point, code length) tuples to represent the Huffman code.</span> <span class='kw'>fn</span> <span class='ident'>from_table</span>(<span class='ident'>table</span>: <span class='kw-2'>&</span>[(<span class='ident'>u32</span>, <span class='ident'>u8</span>)]) <span class='op'>-></span> <span class='ident'>HuffmanDecoder</span> { <span class='kw'>if</span> <span class='ident'>table</span>.<span class='ident'>len</span>() <span class='op'>!=</span> <span class='number'>257</span> { <span class='macro'>panic</span><span class='macro'>!</span>(<span class='string'>"Invalid Huffman code table. It must define exactly 257 symbols."</span>); } <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>decoder_table</span>: <span class='ident'>HashMap</span><span class='op'><</span><span class='ident'>u8</span>, <span class='ident'>HashMap</span><span class='op'><</span><span class='ident'>u32</span>, <span class='ident'>HuffmanCodeSymbol</span><span class='op'>>></span> <span class='op'>=</span> <span class='ident'>HashMap</span>::<span class='ident'>new</span>(); <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>eos_codepoint</span>: <span class='prelude-ty'>Option</span><span class='op'><</span>(<span class='ident'>u32</span>, <span class='ident'>u8</span>)<span class='op'>></span> <span class='op'>=</span> <span class='prelude-val'>None</span>; <span class='kw'>for</span> (<span class='ident'>symbol</span>, <span class='kw-2'>&</span>(<span class='ident'>code</span>, <span class='ident'>code_len</span>)) <span class='kw'>in</span> <span class='ident'>table</span>.<span class='ident'>iter</span>().<span class='ident'>enumerate</span>() { <span class='kw'>if</span> <span class='op'>!</span><span class='ident'>decoder_table</span>.<span class='ident'>contains_key</span>(<span class='kw-2'>&</span><span class='ident'>code_len</span>) { <span class='ident'>decoder_table</span>.<span class='ident'>insert</span>(<span class='ident'>code_len</span>, <span class='ident'>HashMap</span>::<span class='ident'>new</span>()); } <span class='kw'>let</span> <span class='ident'>subtable</span> <span class='op'>=</span> <span class='ident'>decoder_table</span>.<span class='ident'>get_mut</span>(<span class='kw-2'>&</span><span class='ident'>code_len</span>).<span class='ident'>unwrap</span>(); <span class='kw'>let</span> <span class='ident'>huff_symbol</span> <span class='op'>=</span> <span class='ident'>HuffmanCodeSymbol</span>::<span class='ident'>new</span>(<span class='ident'>symbol</span>); <span class='kw'>match</span> <span class='ident'>huff_symbol</span> { <span class='ident'>HuffmanCodeSymbol</span>::<span class='ident'>EndOfString</span> <span class='op'>=></span> { <span class='comment'>// We also remember the code point of the EOS for easier</span> <span class='comment'>// reference later on.</span> <span class='ident'>eos_codepoint</span> <span class='op'>=</span> <span class='prelude-val'>Some</span>((<span class='ident'>code</span>, <span class='ident'>code_len</span>)); }, _ <span class='op'>=></span> {} }; <span class='ident'>subtable</span>.<span class='ident'>insert</span>(<span class='ident'>code</span>, <span class='ident'>huff_symbol</span>); } <span class='ident'>HuffmanDecoder</span> { <span class='ident'>table</span>: <span class='ident'>decoder_table</span>, <span class='ident'>eos_codepoint</span>: <span class='ident'>eos_codepoint</span>.<span class='ident'>unwrap</span>(), } } <span class='doccomment'>/// Constructs a new HuffmanDecoder with the default Huffman code table, as</span> <span class='doccomment'>/// defined in the HPACK-draft-10, Appendix B.</span> <span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>new</span>() <span class='op'>-></span> <span class='ident'>HuffmanDecoder</span> { <span class='ident'>HuffmanDecoder</span>::<span class='ident'>from_table</span>(<span class='ident'>HUFFMAN_CODE_TABLE</span>) } <span class='doccomment'>/// Decodes the buffer `buf` into a newly allocated `Vec`.</span> <span class='doccomment'>///</span> <span class='doccomment'>/// It assumes that the entire buffer should be considered as the Huffman</span> <span class='doccomment'>/// encoding of an octet string and handles the padding rules</span> <span class='doccomment'>/// accordingly.</span> <span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='self'>self</span>, <span class='ident'>buf</span>: <span class='kw-2'>&</span>[<span class='ident'>u8</span>]) <span class='op'>-></span> <span class='ident'>HuffmanDecoderResult</span> { <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>current</span>: <span class='ident'>u32</span> <span class='op'>=</span> <span class='number'>0</span>; <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>current_len</span>: <span class='ident'>u8</span> <span class='op'>=</span> <span class='number'>0</span>; <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>result</span>: <span class='ident'>Vec</span><span class='op'><</span><span class='ident'>u8</span><span class='op'>></span> <span class='op'>=</span> <span class='ident'>Vec</span>::<span class='ident'>new</span>(); <span class='kw'>for</span> <span class='ident'>b</span> <span class='kw'>in</span> <span class='ident'>BitIterator</span>::<span class='ident'>new</span>(<span class='ident'>buf</span>.<span class='ident'>iter</span>()) { <span class='ident'>current_len</span> <span class='op'>+=</span> <span class='number'>1</span>; <span class='ident'>current</span> <span class='op'><<=</span> <span class='number'>1</span>; <span class='kw'>if</span> <span class='ident'>b</span> { <span class='ident'>current</span> <span class='op'>|=</span> <span class='number'>1</span>; } <span class='kw'>if</span> <span class='self'>self</span>.<span class='ident'>table</span>.<span class='ident'>contains_key</span>(<span class='kw-2'>&</span><span class='ident'>current_len</span>) { <span class='kw'>let</span> <span class='ident'>length_table</span> <span class='op'>=</span> <span class='self'>self</span>.<span class='ident'>table</span>.<span class='ident'>get</span>(<span class='kw-2'>&</span><span class='ident'>current_len</span>).<span class='ident'>unwrap</span>(); <span class='kw'>if</span> <span class='ident'>length_table</span>.<span class='ident'>contains_key</span>(<span class='kw-2'>&</span><span class='ident'>current</span>) { <span class='kw'>let</span> <span class='ident'>decoded_symbol</span> <span class='op'>=</span> <span class='kw'>match</span> <span class='ident'>length_table</span>.<span class='ident'>get</span>(<span class='kw-2'>&</span><span class='ident'>current</span>).<span class='ident'>unwrap</span>() { <span class='kw-2'>&</span><span class='ident'>HuffmanCodeSymbol</span>::<span class='ident'>Symbol</span>(<span class='ident'>symbol</span>) <span class='op'>=></span> <span class='ident'>symbol</span>, <span class='kw-2'>&</span><span class='ident'>HuffmanCodeSymbol</span>::<span class='ident'>EndOfString</span> <span class='op'>=></span> { <span class='comment'>// If the EOS symbol is detected within the stream,</span> <span class='comment'>// we need to consider it an error.</span> <span class='kw'>return</span> <span class='prelude-val'>Err</span>(<span class='ident'>HuffmanDecoderError</span>::<span class='ident'>EOSInString</span>); }, }; <span class='ident'>result</span>.<span class='ident'>push</span>(<span class='ident'>decoded_symbol</span>); <span class='ident'>current</span> <span class='op'>=</span> <span class='number'>0</span>; <span class='ident'>current_len</span> <span class='op'>=</span> <span class='number'>0</span>; } } } <span class='comment'>// Now we need to verify that the padding is correct.</span> <span class='comment'>// The spec mandates that the padding must not be strictly longer than</span> <span class='comment'>// 7 bits and that it must represent the most significant bits of the</span> <span class='comment'>// EOS symbol's code.</span> <span class='comment'>// First: the check for the length of the padding</span> <span class='kw'>if</span> <span class='ident'>current_len</span> <span class='op'>></span> <span class='number'>7</span> { <span class='kw'>return</span> <span class='prelude-val'>Err</span>(<span class='ident'>HuffmanDecoderError</span>::<span class='ident'>PaddingTooLarge</span>) } <span class='comment'>// Second: the padding corresponds to the most-significant bits of the</span> <span class='comment'>// EOS symbol.</span> <span class='comment'>// Align both of them to have their most significant bit as the most</span> <span class='comment'>// significant bit of a u32.</span> <span class='kw'>let</span> <span class='ident'>right_align_current</span> <span class='op'>=</span> <span class='kw'>if</span> <span class='ident'>current_len</span> <span class='op'>==</span> <span class='number'>0</span> { <span class='number'>0</span> } <span class='kw'>else</span> { <span class='ident'>current</span> <span class='op'><<</span> (<span class='number'>32</span> <span class='op'>-</span> <span class='ident'>current_len</span>) }; <span class='kw'>let</span> <span class='ident'>right_align_eos</span> <span class='op'>=</span> <span class='self'>self</span>.<span class='ident'>eos_codepoint</span>.<span class='number'>0</span> <span class='op'><<</span> (<span class='number'>32</span> <span class='op'>-</span> <span class='self'>self</span>.<span class='ident'>eos_codepoint</span>.<span class='number'>1</span>); <span class='comment'>// Now take only the necessary amount of most significant bit of EOS.</span> <span class='comment'>// The mask defines a bit pattern of `current_len` leading set bits,</span> <span class='comment'>// followed by the rest of the bits 0.</span> <span class='kw'>let</span> <span class='ident'>mask</span> <span class='op'>=</span> <span class='kw'>if</span> <span class='ident'>current_len</span> <span class='op'>==</span> <span class='number'>0</span> { <span class='number'>0</span> } <span class='kw'>else</span> { ((<span class='number'>1</span> <span class='op'><<</span> <span class='ident'>current_len</span>) <span class='op'>-</span> <span class='number'>1</span>) <span class='op'><<</span> (<span class='number'>32</span> <span class='op'>-</span> <span class='ident'>current_len</span>) }; <span class='comment'>// The mask is now used to strip the unwanted bits of the EOS</span> <span class='kw'>let</span> <span class='ident'>eos_mask</span> <span class='op'>=</span> <span class='ident'>right_align_eos</span> <span class='kw-2'>&</span> <span class='ident'>mask</span>; <span class='kw'>if</span> <span class='ident'>eos_mask</span> <span class='op'>!=</span> <span class='ident'>right_align_current</span> { <span class='kw'>return</span> <span class='prelude-val'>Err</span>(<span class='ident'>HuffmanDecoderError</span>::<span class='ident'>InvalidPadding</span>); } <span class='prelude-val'>Ok</span>(<span class='ident'>result</span>) } } <span class='doccomment'>/// A helper struct that represents an iterator over individual bits of all</span> <span class='doccomment'>/// bytes found in a wrapped Iterator over bytes.</span> <span class='doccomment'>/// Bits are represented as `bool`s, where `true` corresponds to a set bit and</span> <span class='doccomment'>/// `false` to a 0 bit.</span> <span class='doccomment'>///</span> <span class='doccomment'>/// Bits are yielded in order of significance, starting from the</span> <span class='doccomment'>/// most-significant bit.</span> <span class='kw'>struct</span> <span class='ident'>BitIterator</span><span class='op'><</span><span class='lifetime'>'a</span>, <span class='ident'>I</span>: <span class='ident'>Iterator</span><span class='op'>></span> { <span class='ident'>buffer_iterator</span>: <span class='ident'>I</span>, <span class='ident'>current_byte</span>: <span class='prelude-ty'>Option</span><span class='op'><</span><span class='kw-2'>&</span><span class='lifetime'>'a</span> <span class='ident'>u8</span><span class='op'>></span>, <span class='doccomment'>/// The bit-position within the current byte</span> <span class='ident'>pos</span>: <span class='ident'>u8</span>, } <span class='kw'>impl</span><span class='op'><</span><span class='lifetime'>'a</span>, <span class='ident'>I</span>: <span class='ident'>Iterator</span><span class='op'>></span> <span class='ident'>BitIterator</span><span class='op'><</span><span class='lifetime'>'a</span>, <span class='ident'>I</span><span class='op'>></span> <span class='kw'>where</span> <span class='ident'>I</span>: <span class='ident'>Iterator</span><span class='op'><</span><span class='ident'>Item</span><span class='op'>=</span><span class='kw-2'>&</span><span class='lifetime'>'a</span> <span class='ident'>u8</span><span class='op'>></span> { <span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>new</span>(<span class='ident'>iterator</span>: <span class='ident'>I</span>) <span class='op'>-></span> <span class='ident'>BitIterator</span><span class='op'><</span><span class='lifetime'>'a</span>, <span class='ident'>I</span><span class='op'>></span> { <span class='ident'>BitIterator</span>::<span class='op'><</span><span class='lifetime'>'a</span>, <span class='ident'>I</span><span class='op'>></span> { <span class='ident'>buffer_iterator</span>: <span class='ident'>iterator</span>, <span class='ident'>current_byte</span>: <span class='prelude-val'>None</span>, <span class='ident'>pos</span>: <span class='number'>7</span>, } } } <span class='kw'>impl</span><span class='op'><</span><span class='lifetime'>'a</span>, <span class='ident'>I</span><span class='op'>></span> <span class='ident'>Iterator</span> <span class='kw'>for</span> <span class='ident'>BitIterator</span><span class='op'><</span><span class='lifetime'>'a</span>, <span class='ident'>I</span><span class='op'>></span> <span class='kw'>where</span> <span class='ident'>I</span>: <span class='ident'>Iterator</span><span class='op'><</span><span class='ident'>Item</span><span class='op'>=</span><span class='kw-2'>&</span><span class='lifetime'>'a</span> <span class='ident'>u8</span><span class='op'>></span> { <span class='kw'>type</span> <span class='ident'>Item</span> <span class='op'>=</span> <span class='ident'>bool</span>; <span class='kw'>fn</span> <span class='ident'>next</span>(<span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='self'>self</span>) <span class='op'>-></span> <span class='prelude-ty'>Option</span><span class='op'><</span><span class='ident'>bool</span><span class='op'>></span> { <span class='kw'>if</span> <span class='self'>self</span>.<span class='ident'>current_byte</span>.<span class='ident'>is_none</span>() { <span class='self'>self</span>.<span class='ident'>current_byte</span> <span class='op'>=</span> <span class='self'>self</span>.<span class='ident'>buffer_iterator</span>.<span class='ident'>next</span>(); <span class='self'>self</span>.<span class='ident'>pos</span> <span class='op'>=</span> <span class='number'>7</span>; } <span class='comment'>// If we still have `None`, it means the buffer has been exhausted</span> <span class='kw'>if</span> <span class='self'>self</span>.<span class='ident'>current_byte</span>.<span class='ident'>is_none</span>() { <span class='kw'>return</span> <span class='prelude-val'>None</span>; } <span class='kw'>let</span> <span class='ident'>b</span> <span class='op'>=</span> <span class='op'>*</span><span class='self'>self</span>.<span class='ident'>current_byte</span>.<span class='ident'>unwrap</span>(); <span class='kw'>let</span> <span class='ident'>is_set</span> <span class='op'>=</span> (<span class='ident'>b</span> <span class='kw-2'>&</span> (<span class='number'>1</span> <span class='op'><<</span> <span class='self'>self</span>.<span class='ident'>pos</span>)) <span class='op'>==</span> (<span class='number'>1</span> <span class='op'><<</span> <span class='self'>self</span>.<span class='ident'>pos</span>); <span class='kw'>if</span> <span class='self'>self</span>.<span class='ident'>pos</span> <span class='op'>==</span> <span class='number'>0</span> { <span class='comment'>// We have exhausted all bits from the current byte -- try to get</span> <span class='comment'>// a new one on the next pass.</span> <span class='self'>self</span>.<span class='ident'>current_byte</span> <span class='op'>=</span> <span class='prelude-val'>None</span>; } <span class='kw'>else</span> { <span class='comment'>// Still more bits left here...</span> <span class='self'>self</span>.<span class='ident'>pos</span> <span class='op'>-=</span> <span class='number'>1</span>; } <span class='prelude-val'>Some</span>(<span class='ident'>is_set</span>) } } <span class='kw'>static</span> <span class='ident'>HUFFMAN_CODE_TABLE</span>: <span class='kw-2'>&</span><span class='lifetime'>'static</span> [(<span class='ident'>u32</span>, <span class='ident'>u8</span>)] <span class='op'>=</span> <span class='kw-2'>&</span>[ (<span class='number'>0x1ff8</span>, <span class='number'>13</span>), (<span class='number'>0x7fffd8</span>, <span class='number'>23</span>), (<span class='number'>0xfffffe2</span>, <span class='number'>28</span>), (<span class='number'>0xfffffe3</span>, <span class='number'>28</span>), (<span class='number'>0xfffffe4</span>, <span class='number'>28</span>), (<span class='number'>0xfffffe5</span>, <span class='number'>28</span>), (<span class='number'>0xfffffe6</span>, <span class='number'>28</span>), (<span class='number'>0xfffffe7</span>, <span class='number'>28</span>), (<span class='number'>0xfffffe8</span>, <span class='number'>28</span>), (<span class='number'>0xffffea</span>, <span class='number'>24</span>), (<span class='number'>0x3ffffffc</span>, <span class='number'>30</span>), (<span class='number'>0xfffffe9</span>, <span class='number'>28</span>), (<span class='number'>0xfffffea</span>, <span class='number'>28</span>), (<span class='number'>0x3ffffffd</span>, <span class='number'>30</span>), (<span class='number'>0xfffffeb</span>, <span class='number'>28</span>), (<span class='number'>0xfffffec</span>, <span class='number'>28</span>), (<span class='number'>0xfffffed</span>, <span class='number'>28</span>), (<span class='number'>0xfffffee</span>, <span class='number'>28</span>), (<span class='number'>0xfffffef</span>, <span class='number'>28</span>), (<span class='number'>0xffffff0</span>, <span class='number'>28</span>), (<span class='number'>0xffffff1</span>, <span class='number'>28</span>), (<span class='number'>0xffffff2</span>, <span class='number'>28</span>), (<span class='number'>0x3ffffffe</span>, <span class='number'>30</span>), (<span class='number'>0xffffff3</span>, <span class='number'>28</span>), (<span class='number'>0xffffff4</span>, <span class='number'>28</span>), (<span class='number'>0xffffff5</span>, <span class='number'>28</span>), (<span class='number'>0xffffff6</span>, <span class='number'>28</span>), (<span class='number'>0xffffff7</span>, <span class='number'>28</span>), (<span class='number'>0xffffff8</span>, <span class='number'>28</span>), (<span class='number'>0xffffff9</span>, <span class='number'>28</span>), (<span class='number'>0xffffffa</span>, <span class='number'>28</span>), (<span class='number'>0xffffffb</span>, <span class='number'>28</span>), (<span class='number'>0x14</span>, <span class='number'>6</span>), (<span class='number'>0x3f8</span>, <span class='number'>10</span>), (<span class='number'>0x3f9</span>, <span class='number'>10</span>), (<span class='number'>0xffa</span>, <span class='number'>12</span>), (<span class='number'>0x1ff9</span>, <span class='number'>13</span>), (<span class='number'>0x15</span>, <span class='number'>6</span>), (<span class='number'>0xf8</span>, <span class='number'>8</span>), (<span class='number'>0x7fa</span>, <span class='number'>11</span>), (<span class='number'>0x3fa</span>, <span class='number'>10</span>), (<span class='number'>0x3fb</span>, <span class='number'>10</span>), (<span class='number'>0xf9</span>, <span class='number'>8</span>), (<span class='number'>0x7fb</span>, <span class='number'>11</span>), (<span class='number'>0xfa</span>, <span class='number'>8</span>), (<span class='number'>0x16</span>, <span class='number'>6</span>), (<span class='number'>0x17</span>, <span class='number'>6</span>), (<span class='number'>0x18</span>, <span class='number'>6</span>), (<span class='number'>0x0</span>, <span class='number'>5</span>), (<span class='number'>0x1</span>, <span class='number'>5</span>), (<span class='number'>0x2</span>, <span class='number'>5</span>), (<span class='number'>0x19</span>, <span class='number'>6</span>), (<span class='number'>0x1a</span>, <span class='number'>6</span>), (<span class='number'>0x1b</span>, <span class='number'>6</span>), (<span class='number'>0x1c</span>, <span class='number'>6</span>), (<span class='number'>0x1d</span>, <span class='number'>6</span>), (<span class='number'>0x1e</span>, <span class='number'>6</span>), (<span class='number'>0x1f</span>, <span class='number'>6</span>), (<span class='number'>0x5c</span>, <span class='number'>7</span>), (<span class='number'>0xfb</span>, <span class='number'>8</span>), (<span class='number'>0x7ffc</span>, <span class='number'>15</span>), (<span class='number'>0x20</span>, <span class='number'>6</span>), (<span class='number'>0xffb</span>, <span class='number'>12</span>), (<span class='number'>0x3fc</span>, <span class='number'>10</span>), (<span class='number'>0x1ffa</span>, <span class='number'>13</span>), (<span class='number'>0x21</span>, <span class='number'>6</span>), (<span class='number'>0x5d</span>, <span class='number'>7</span>), (<span class='number'>0x5e</span>, <span class='number'>7</span>), (<span class='number'>0x5f</span>, <span class='number'>7</span>), (<span class='number'>0x60</span>, <span class='number'>7</span>), (<span class='number'>0x61</span>, <span class='number'>7</span>), (<span class='number'>0x62</span>, <span class='number'>7</span>), (<span class='number'>0x63</span>, <span class='number'>7</span>), (<span class='number'>0x64</span>, <span class='number'>7</span>), (<span class='number'>0x65</span>, <span class='number'>7</span>), (<span class='number'>0x66</span>, <span class='number'>7</span>), (<span class='number'>0x67</span>, <span class='number'>7</span>), (<span class='number'>0x68</span>, <span class='number'>7</span>), (<span class='number'>0x69</span>, <span class='number'>7</span>), (<span class='number'>0x6a</span>, <span class='number'>7</span>), (<span class='number'>0x6b</span>, <span class='number'>7</span>), (<span class='number'>0x6c</span>, <span class='number'>7</span>), (<span class='number'>0x6d</span>, <span class='number'>7</span>), (<span class='number'>0x6e</span>, <span class='number'>7</span>), (<span class='number'>0x6f</span>, <span class='number'>7</span>), (<span class='number'>0x70</span>, <span class='number'>7</span>), (<span class='number'>0x71</span>, <span class='number'>7</span>), (<span class='number'>0x72</span>, <span class='number'>7</span>), (<span class='number'>0xfc</span>, <span class='number'>8</span>), (<span class='number'>0x73</span>, <span class='number'>7</span>), (<span class='number'>0xfd</span>, <span class='number'>8</span>), (<span class='number'>0x1ffb</span>, <span class='number'>13</span>), (<span class='number'>0x7fff0</span>, <span class='number'>19</span>), (<span class='number'>0x1ffc</span>, <span class='number'>13</span>), (<span class='number'>0x3ffc</span>, <span class='number'>14</span>), (<span class='number'>0x22</span>, <span class='number'>6</span>), (<span class='number'>0x7ffd</span>, <span class='number'>15</span>), (<span class='number'>0x3</span>, <span class='number'>5</span>), (<span class='number'>0x23</span>, <span class='number'>6</span>), (<span class='number'>0x4</span>, <span class='number'>5</span>), (<span class='number'>0x24</span>, <span class='number'>6</span>), (<span class='number'>0x5</span>, <span class='number'>5</span>), (<span class='number'>0x25</span>, <span class='number'>6</span>), (<span class='number'>0x26</span>, <span class='number'>6</span>), (<span class='number'>0x27</span>, <span class='number'>6</span>), (<span class='number'>0x6</span>, <span class='number'>5</span>), (<span class='number'>0x74</span>, <span class='number'>7</span>), (<span class='number'>0x75</span>, <span class='number'>7</span>), (<span class='number'>0x28</span>, <span class='number'>6</span>), (<span class='number'>0x29</span>, <span class='number'>6</span>), (<span class='number'>0x2a</span>, <span class='number'>6</span>), (<span class='number'>0x7</span>, <span class='number'>5</span>), (<span class='number'>0x2b</span>, <span class='number'>6</span>), (<span class='number'>0x76</span>, <span class='number'>7</span>), (<span class='number'>0x2c</span>, <span class='number'>6</span>), (<span class='number'>0x8</span>, <span class='number'>5</span>), (<span class='number'>0x9</span>, <span class='number'>5</span>), (<span class='number'>0x2d</span>, <span class='number'>6</span>), (<span class='number'>0x77</span>, <span class='number'>7</span>), (<span class='number'>0x78</span>, <span class='number'>7</span>), (<span class='number'>0x79</span>, <span class='number'>7</span>), (<span class='number'>0x7a</span>, <span class='number'>7</span>), (<span class='number'>0x7b</span>, <span class='number'>7</span>), (<span class='number'>0x7ffe</span>, <span class='number'>15</span>), (<span class='number'>0x7fc</span>, <span class='number'>11</span>), (<span class='number'>0x3ffd</span>, <span class='number'>14</span>), (<span class='number'>0x1ffd</span>, <span class='number'>13</span>), (<span class='number'>0xffffffc</span>, <span class='number'>28</span>), (<span class='number'>0xfffe6</span>, <span class='number'>20</span>), (<span class='number'>0x3fffd2</span>, <span class='number'>22</span>), (<span class='number'>0xfffe7</span>, <span class='number'>20</span>), (<span class='number'>0xfffe8</span>, <span class='number'>20</span>), (<span class='number'>0x3fffd3</span>, <span class='number'>22</span>), (<span class='number'>0x3fffd4</span>, <span class='number'>22</span>), (<span class='number'>0x3fffd5</span>, <span class='number'>22</span>), (<span class='number'>0x7fffd9</span>, <span class='number'>23</span>), (<span class='number'>0x3fffd6</span>, <span class='number'>22</span>), (<span class='number'>0x7fffda</span>, <span class='number'>23</span>), (<span class='number'>0x7fffdb</span>, <span class='number'>23</span>), (<span class='number'>0x7fffdc</span>, <span class='number'>23</span>), (<span class='number'>0x7fffdd</span>, <span class='number'>23</span>), (<span class='number'>0x7fffde</span>, <span class='number'>23</span>), (<span class='number'>0xffffeb</span>, <span class='number'>24</span>), (<span class='number'>0x7fffdf</span>, <span class='number'>23</span>), (<span class='number'>0xffffec</span>, <span class='number'>24</span>), (<span class='number'>0xffffed</span>, <span class='number'>24</span>), (<span class='number'>0x3fffd7</span>, <span class='number'>22</span>), (<span class='number'>0x7fffe0</span>, <span class='number'>23</span>), (<span class='number'>0xffffee</span>, <span class='number'>24</span>), (<span class='number'>0x7fffe1</span>, <span class='number'>23</span>), (<span class='number'>0x7fffe2</span>, <span class='number'>23</span>), (<span class='number'>0x7fffe3</span>, <span class='number'>23</span>), (<span class='number'>0x7fffe4</span>, <span class='number'>23</span>), (<span class='number'>0x1fffdc</span>, <span class='number'>21</span>), (<span class='number'>0x3fffd8</span>, <span class='number'>22</span>), (<span class='number'>0x7fffe5</span>, <span class='number'>23</span>), (<span class='number'>0x3fffd9</span>, <span class='number'>22</span>), (<span class='number'>0x7fffe6</span>, <span class='number'>23</span>), (<span class='number'>0x7fffe7</span>, <span class='number'>23</span>), (<span class='number'>0xffffef</span>, <span class='number'>24</span>), (<span class='number'>0x3fffda</span>, <span class='number'>22</span>), (<span class='number'>0x1fffdd</span>, <span class='number'>21</span>), (<span class='number'>0xfffe9</span>, <span class='number'>20</span>), (<span class='number'>0x3fffdb</span>, <span class='number'>22</span>), (<span class='number'>0x3fffdc</span>, <span class='number'>22</span>), (<span class='number'>0x7fffe8</span>, <span class='number'>23</span>), (<span class='number'>0x7fffe9</span>, <span class='number'>23</span>), (<span class='number'>0x1fffde</span>, <span class='number'>21</span>), (<span class='number'>0x7fffea</span>, <span class='number'>23</span>), (<span class='number'>0x3fffdd</span>, <span class='number'>22</span>), (<span class='number'>0x3fffde</span>, <span class='number'>22</span>), (<span class='number'>0xfffff0</span>, <span class='number'>24</span>), (<span class='number'>0x1fffdf</span>, <span class='number'>21</span>), (<span class='number'>0x3fffdf</span>, <span class='number'>22</span>), (<span class='number'>0x7fffeb</span>, <span class='number'>23</span>), (<span class='number'>0x7fffec</span>, <span class='number'>23</span>), (<span class='number'>0x1fffe0</span>, <span class='number'>21</span>), (<span class='number'>0x1fffe1</span>, <span class='number'>21</span>), (<span class='number'>0x3fffe0</span>, <span class='number'>22</span>), (<span class='number'>0x1fffe2</span>, <span class='number'>21</span>), (<span class='number'>0x7fffed</span>, <span class='number'>23</span>), (<span class='number'>0x3fffe1</span>, <span class='number'>22</span>), (<span class='number'>0x7fffee</span>, <span class='number'>23</span>), (<span class='number'>0x7fffef</span>, <span class='number'>23</span>), (<span class='number'>0xfffea</span>, <span class='number'>20</span>), (<span class='number'>0x3fffe2</span>, <span class='number'>22</span>), (<span class='number'>0x3fffe3</span>, <span class='number'>22</span>), (<span class='number'>0x3fffe4</span>, <span class='number'>22</span>), (<span class='number'>0x7ffff0</span>, <span class='number'>23</span>), (<span class='number'>0x3fffe5</span>, <span class='number'>22</span>), (<span class='number'>0x3fffe6</span>, <span class='number'>22</span>), (<span class='number'>0x7ffff1</span>, <span class='number'>23</span>), (<span class='number'>0x3ffffe0</span>, <span class='number'>26</span>), (<span class='number'>0x3ffffe1</span>, <span class='number'>26</span>), (<span class='number'>0xfffeb</span>, <span class='number'>20</span>), (<span class='number'>0x7fff1</span>, <span class='number'>19</span>), (<span class='number'>0x3fffe7</span>, <span class='number'>22</span>), (<span class='number'>0x7ffff2</span>, <span class='number'>23</span>), (<span class='number'>0x3fffe8</span>, <span class='number'>22</span>), (<span class='number'>0x1ffffec</span>, <span class='number'>25</span>), (<span class='number'>0x3ffffe2</span>, <span class='number'>26</span>), (<span class='number'>0x3ffffe3</span>, <span class='number'>26</span>), (<span class='number'>0x3ffffe4</span>, <span class='number'>26</span>), (<span class='number'>0x7ffffde</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffdf</span>, <span class='number'>27</span>), (<span class='number'>0x3ffffe5</span>, <span class='number'>26</span>), (<span class='number'>0xfffff1</span>, <span class='number'>24</span>), (<span class='number'>0x1ffffed</span>, <span class='number'>25</span>), (<span class='number'>0x7fff2</span>, <span class='number'>19</span>), (<span class='number'>0x1fffe3</span>, <span class='number'>21</span>), (<span class='number'>0x3ffffe6</span>, <span class='number'>26</span>), (<span class='number'>0x7ffffe0</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffe1</span>, <span class='number'>27</span>), (<span class='number'>0x3ffffe7</span>, <span class='number'>26</span>), (<span class='number'>0x7ffffe2</span>, <span class='number'>27</span>), (<span class='number'>0xfffff2</span>, <span class='number'>24</span>), (<span class='number'>0x1fffe4</span>, <span class='number'>21</span>), (<span class='number'>0x1fffe5</span>, <span class='number'>21</span>), (<span class='number'>0x3ffffe8</span>, <span class='number'>26</span>), (<span class='number'>0x3ffffe9</span>, <span class='number'>26</span>), (<span class='number'>0xffffffd</span>, <span class='number'>28</span>), (<span class='number'>0x7ffffe3</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffe4</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffe5</span>, <span class='number'>27</span>), (<span class='number'>0xfffec</span>, <span class='number'>20</span>), (<span class='number'>0xfffff3</span>, <span class='number'>24</span>), (<span class='number'>0xfffed</span>, <span class='number'>20</span>), (<span class='number'>0x1fffe6</span>, <span class='number'>21</span>), (<span class='number'>0x3fffe9</span>, <span class='number'>22</span>), (<span class='number'>0x1fffe7</span>, <span class='number'>21</span>), (<span class='number'>0x1fffe8</span>, <span class='number'>21</span>), (<span class='number'>0x7ffff3</span>, <span class='number'>23</span>), (<span class='number'>0x3fffea</span>, <span class='number'>22</span>), (<span class='number'>0x3fffeb</span>, <span class='number'>22</span>), (<span class='number'>0x1ffffee</span>, <span class='number'>25</span>), (<span class='number'>0x1ffffef</span>, <span class='number'>25</span>), (<span class='number'>0xfffff4</span>, <span class='number'>24</span>), (<span class='number'>0xfffff5</span>, <span class='number'>24</span>), (<span class='number'>0x3ffffea</span>, <span class='number'>26</span>), (<span class='number'>0x7ffff4</span>, <span class='number'>23</span>), (<span class='number'>0x3ffffeb</span>, <span class='number'>26</span>), (<span class='number'>0x7ffffe6</span>, <span class='number'>27</span>), (<span class='number'>0x3ffffec</span>, <span class='number'>26</span>), (<span class='number'>0x3ffffed</span>, <span class='number'>26</span>), (<span class='number'>0x7ffffe7</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffe8</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffe9</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffea</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffeb</span>, <span class='number'>27</span>), (<span class='number'>0xffffffe</span>, <span class='number'>28</span>), (<span class='number'>0x7ffffec</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffed</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffee</span>, <span class='number'>27</span>), (<span class='number'>0x7ffffef</span>, <span class='number'>27</span>), (<span class='number'>0x7fffff0</span>, <span class='number'>27</span>), (<span class='number'>0x3ffffee</span>, <span class='number'>26</span>), (<span class='number'>0x3fffffff</span>, <span class='number'>30</span>), ]; <span class='attribute'>#[<span class='ident'>cfg</span>(<span class='ident'>test</span>)]</span> <span class='kw'>mod</span> <span class='ident'>tests</span> { <span class='kw'>use</span> <span class='kw'>super</span>::<span class='ident'>BitIterator</span>; <span class='kw'>use</span> <span class='kw'>super</span>::<span class='ident'>HuffmanDecoder</span>; <span class='kw'>use</span> <span class='kw'>super</span>::<span class='ident'>HuffmanDecoderError</span>; <span class='doccomment'>/// A helper function that converts the given slice containing values `1`</span> <span class='doccomment'>/// and `0` to a `Vec` of `bool`s, according to the number.</span> <span class='kw'>fn</span> <span class='ident'>to_expected_bit_result</span>(<span class='ident'>numbers</span>: <span class='kw-2'>&</span>[<span class='ident'>u8</span>]) <span class='op'>-></span> <span class='ident'>Vec</span><span class='op'><</span><span class='ident'>bool</span><span class='op'>></span> { <span class='ident'>numbers</span>.<span class='ident'>iter</span>().<span class='ident'>map</span>(<span class='op'>|</span><span class='ident'>b</span><span class='op'>|</span> <span class='op'>-></span> <span class='ident'>bool</span> { <span class='op'>*</span><span class='ident'>b</span> <span class='op'>==</span> <span class='number'>1</span> }).<span class='ident'>collect</span>() } <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_bit_iterator_single_byte</span>() { <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='ident'>to_expected_bit_result</span>( <span class='kw-2'>&</span>[<span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>]); <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>res</span>: <span class='ident'>Vec</span><span class='op'><</span><span class='ident'>bool</span><span class='op'>></span> <span class='op'>=</span> <span class='ident'>Vec</span>::<span class='ident'>new</span>(); <span class='kw'>for</span> <span class='ident'>b</span> <span class='kw'>in</span> <span class='ident'>BitIterator</span>::<span class='ident'>new</span>(<span class='macro'>vec</span><span class='macro'>!</span>[<span class='number'>10u8</span>].<span class='ident'>iter</span>()) { <span class='ident'>res</span>.<span class='ident'>push</span>(<span class='ident'>b</span>); } <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>res</span>, <span class='ident'>expected_result</span>); } <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_bit_iterator_multiple_bytes</span>() { <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='ident'>to_expected_bit_result</span>( <span class='kw-2'>&</span>[<span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>1</span>, <span class='number'>1</span>, <span class='number'>1</span>, <span class='number'>1</span>, <span class='number'>1</span>, <span class='number'>1</span>, <span class='number'>1</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>1</span>, <span class='number'>0</span>]); <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>res</span>: <span class='ident'>Vec</span><span class='op'><</span><span class='ident'>bool</span><span class='op'>></span> <span class='op'>=</span> <span class='ident'>Vec</span>::<span class='ident'>new</span>(); <span class='kw'>for</span> <span class='ident'>b</span> <span class='kw'>in</span> <span class='ident'>BitIterator</span>::<span class='ident'>new</span>(<span class='macro'>vec</span><span class='macro'>!</span>[<span class='number'>10u8</span>, <span class='number'>255</span>, <span class='number'>128</span>, <span class='number'>1</span>, <span class='number'>0</span>, <span class='number'>170</span>].<span class='ident'>iter</span>()) { <span class='ident'>res</span>.<span class='ident'>push</span>(<span class='ident'>b</span>); } <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>res</span>, <span class='ident'>expected_result</span>); } <span class='doccomment'>/// Simple tests for the Huffman decoder -- whether it can decode a single</span> <span class='doccomment'>/// character code represented additionally with only a single byte.</span> <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_huffman_code_single_byte</span>() { <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>decoder</span> <span class='op'>=</span> <span class='ident'>HuffmanDecoder</span>::<span class='ident'>new</span>(); <span class='comment'>// (The + (2^n - 1) at the final byte is to add the correct expected</span> <span class='comment'>// padding: 1s)</span> { <span class='comment'>// We need to shift it by 3, since we need the top-order bytes to</span> <span class='comment'>// start the code point.</span> <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [(<span class='number'>0x7</span> <span class='op'><<</span> <span class='number'>3</span>) <span class='op'>+</span> <span class='number'>7</span>]; <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='string'>b'o'</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>).<span class='ident'>ok</span>().<span class='ident'>unwrap</span>(); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>result</span>, <span class='ident'>expected_result</span>); } { <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>0x0</span> <span class='op'>+</span> <span class='number'>7</span>]; <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='string'>b'0'</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>).<span class='ident'>ok</span>().<span class='ident'>unwrap</span>(); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>result</span>, <span class='ident'>expected_result</span>); } { <span class='comment'>// The length of the codepoint is 6, so we shift by two</span> <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [(<span class='number'>0x21</span> <span class='op'><<</span> <span class='number'>2</span>) <span class='op'>+</span> <span class='number'>3</span>]; <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='string'>b'A'</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>).<span class='ident'>ok</span>().<span class='ident'>unwrap</span>(); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>result</span>, <span class='ident'>expected_result</span>); } } <span class='doccomment'>/// Tests that the Huffman decoder can decode a single character made of</span> <span class='doccomment'>/// multiple bytes.</span> <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_huffman_code_single_char_multiple_byte</span>() { <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>decoder</span> <span class='op'>=</span> <span class='ident'>HuffmanDecoder</span>::<span class='ident'>new</span>(); <span class='comment'>// (The + (2^n - 1) at the final byte is to add the correct expected</span> <span class='comment'>// padding: 1s)</span> { <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>255</span>, <span class='number'>160</span> <span class='op'>+</span> <span class='number'>15</span>]; <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='string'>b'#'</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>).<span class='ident'>ok</span>().<span class='ident'>unwrap</span>(); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>result</span>, <span class='ident'>expected_result</span>); } { <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>255</span>, <span class='number'>200</span> <span class='op'>+</span> <span class='number'>7</span>]; <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='string'>b'$'</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>).<span class='ident'>ok</span>().<span class='ident'>unwrap</span>(); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>result</span>, <span class='ident'>expected_result</span>); } { <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>255</span>, <span class='number'>255</span>, <span class='number'>255</span>, <span class='number'>240</span> <span class='op'>+</span> <span class='number'>3</span>]; <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='number'>10</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>).<span class='ident'>ok</span>().<span class='ident'>unwrap</span>(); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>result</span>, <span class='ident'>expected_result</span>); } } <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_huffman_code_multiple_chars</span>() { <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>decoder</span> <span class='op'>=</span> <span class='ident'>HuffmanDecoder</span>::<span class='ident'>new</span>(); { <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>254</span>, <span class='number'>1</span>]; <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='string'>b'!'</span>, <span class='string'>b'0'</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>).<span class='ident'>ok</span>().<span class='ident'>unwrap</span>(); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>result</span>, <span class='ident'>expected_result</span>); } { <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [(<span class='number'>0x14</span> <span class='op'><<</span> <span class='number'>2</span>) <span class='op'>|</span> <span class='number'>0x3</span>, <span class='number'>248</span>]; <span class='kw'>let</span> <span class='ident'>expected_result</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>[<span class='string'>b' '</span>, <span class='string'>b'!'</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>).<span class='ident'>ok</span>().<span class='ident'>unwrap</span>(); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>result</span>, <span class='ident'>expected_result</span>); } } <span class='doccomment'>/// Tests that if we find the EOS symbol in the stream, we consider it an</span> <span class='doccomment'>/// error.</span> <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_eos_is_error</span>() { <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>decoder</span> <span class='op'>=</span> <span class='ident'>HuffmanDecoder</span>::<span class='ident'>new</span>(); { <span class='comment'>// The EOS is an all-ones pattern of length 30</span> <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>0xFF</span>, <span class='number'>0xFF</span>, <span class='number'>0xFF</span>, <span class='number'>0xFF</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>HuffmanDecoderError</span>::<span class='ident'>EOSInString</span>, <span class='kw'>match</span> <span class='ident'>result</span> { <span class='prelude-val'>Err</span>(<span class='ident'>e</span>) <span class='op'>=></span> <span class='ident'>e</span>, _ <span class='op'>=></span> <span class='macro'>panic</span><span class='macro'>!</span>(<span class='string'>"Expected error due to EOS symbol in string"</span>), }); } { <span class='comment'>// Full EOS after a valid character.</span> <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>0x3F</span>, <span class='number'>0xFF</span>, <span class='number'>0xFF</span>, <span class='number'>0xFF</span>, <span class='number'>0xFF</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>HuffmanDecoderError</span>::<span class='ident'>EOSInString</span>, <span class='kw'>match</span> <span class='ident'>result</span> { <span class='prelude-val'>Err</span>(<span class='ident'>e</span>) <span class='op'>=></span> <span class='ident'>e</span>, _ <span class='op'>=></span> <span class='macro'>panic</span><span class='macro'>!</span>(<span class='string'>"Expected error due to EOS symbol in string"</span>), }); } } <span class='doccomment'>/// Tests that when there are 7 or less padding bits, the string is</span> <span class='doccomment'>/// correctly decoded.</span> <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_short_padding_okay</span>() { <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>decoder</span> <span class='op'>=</span> <span class='ident'>HuffmanDecoder</span>::<span class='ident'>new</span>(); <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>0x3F</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='string'>b"o"</span>.<span class='ident'>to_vec</span>(), <span class='ident'>result</span>.<span class='ident'>ok</span>().<span class='ident'>unwrap</span>()); } <span class='doccomment'>/// Tests that when there are more than 7 padding bits, we get an error.</span> <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_padding_too_long</span>() { <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>decoder</span> <span class='op'>=</span> <span class='ident'>HuffmanDecoder</span>::<span class='ident'>new</span>(); <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>0x3F</span>, <span class='number'>0xFF</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>HuffmanDecoderError</span>::<span class='ident'>PaddingTooLarge</span>, <span class='kw'>match</span> <span class='ident'>result</span> { <span class='prelude-val'>Err</span>(<span class='ident'>e</span>) <span class='op'>=></span> <span class='ident'>e</span>, _ <span class='op'>=></span> <span class='macro'>panic</span><span class='macro'>!</span>(<span class='string'>"Expected `PaddingTooLarge` error"</span>), }); } <span class='doccomment'>/// Tests that when there is a certain number of padding bits that deviate</span> <span class='doccomment'>/// from the most significant bits of the EOS symbol, we get an error.</span> <span class='attribute'>#[<span class='ident'>test</span>]</span> <span class='kw'>fn</span> <span class='ident'>test_padding_invalid</span>() { <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>decoder</span> <span class='op'>=</span> <span class='ident'>HuffmanDecoder</span>::<span class='ident'>new</span>(); { <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>0x3E</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>HuffmanDecoderError</span>::<span class='ident'>InvalidPadding</span>, <span class='kw'>match</span> <span class='ident'>result</span> { <span class='prelude-val'>Err</span>(<span class='ident'>e</span>) <span class='op'>=></span> <span class='ident'>e</span>, _ <span class='op'>=></span> <span class='macro'>panic</span><span class='macro'>!</span>(<span class='string'>"Expected `InvalidPadding` error"</span>), }); } { <span class='kw'>let</span> <span class='ident'>hex_buffer</span> <span class='op'>=</span> [<span class='number'>254</span>, <span class='number'>0</span>]; <span class='kw'>let</span> <span class='ident'>result</span> <span class='op'>=</span> <span class='ident'>decoder</span>.<span class='ident'>decode</span>(<span class='kw-2'>&</span><span class='ident'>hex_buffer</span>); <span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='ident'>HuffmanDecoderError</span>::<span class='ident'>InvalidPadding</span>, <span class='kw'>match</span> <span class='ident'>result</span> { <span class='prelude-val'>Err</span>(<span class='ident'>e</span>) <span class='op'>=></span> <span class='ident'>e</span>, _ <span class='op'>=></span> <span class='macro'>panic</span><span class='macro'>!</span>(<span class='string'>"Expected `InvalidPadding` error"</span>), }); } } } </pre> </section> <section id='search' class="content hidden"></section> <section class="footer"></section> <aside id="help" class="hidden"> <div> <h1 class="hidden">Help</h1> <div class="shortcuts"> <h2>Keyboard Shortcuts</h2> <dl> <dt>?</dt> <dd>Show this help dialog</dd> <dt>S</dt> <dd>Focus the search field</dd> <dt>⇤</dt> <dd>Move up in search results</dd> <dt>⇥</dt> <dd>Move down in search results</dd> <dt>⏎</dt> <dd>Go to active search result</dd> <dt>+</dt> <dd>Collapse/expand all sections</dd> </dl> </div> <div class="infos"> <h2>Search Tricks</h2> <p> Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type. </p> <p> Accepted types are: <code>fn</code>, <code>mod</code>, 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