| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/git/checkouts/tantivy-65d0bbbddbbd5d02/433372d/src/positions/serializer.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>serializer.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../tantivy/index.html"><div class="logo-container"> |
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| </pre><pre class="rust"><code><span class="kw">use </span>std::io::{<span class="self">self</span>, Write}; |
| |
| <span class="kw">use </span>common::{BinarySerializable, CountingWriter, VInt}; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::positions::COMPRESSION_BLOCK_SIZE; |
| <span class="kw">use </span><span class="kw">crate</span>::postings::compression::{BlockEncoder, VIntEncoder}; |
| |
| <span class="doccomment">/// The PositionSerializer is in charge of serializing all of the positions |
| /// of all of the terms of a given field. |
| /// |
| /// It is valid to call write_position_delta more than once per term. |
| </span><span class="kw">pub struct </span>PositionSerializer<W: io::Write> { |
| block_encoder: BlockEncoder, |
| positions_wrt: CountingWriter<W>, |
| positions_buffer: Vec<u8>, |
| block: Vec<u32>, |
| bit_widths: Vec<u8>, |
| } |
| |
| <span class="kw">impl</span><W: io::Write> PositionSerializer<W> { |
| <span class="doccomment">/// Creates a new PositionSerializer writing into the given positions_wrt. |
| </span><span class="kw">pub fn </span>new(positions_wrt: W) -> PositionSerializer<W> { |
| PositionSerializer { |
| block_encoder: BlockEncoder::new(), |
| positions_wrt: CountingWriter::wrap(positions_wrt), |
| positions_buffer: Vec::with_capacity(<span class="number">128_000</span>), |
| block: Vec::with_capacity(<span class="number">128</span>), |
| bit_widths: Vec::new(), |
| } |
| } |
| |
| <span class="doccomment">/// Returns the number of bytes written in the positions write object |
| /// at this point. |
| /// When called before writing the positions of a term, this value is used as |
| /// start offset. |
| /// When called after writing the positions of a term, this value is used as |
| /// end offset. |
| </span><span class="kw">pub fn </span>written_bytes(<span class="kw-2">&</span><span class="self">self</span>) -> u64 { |
| <span class="self">self</span>.positions_wrt.written_bytes() |
| } |
| |
| <span class="kw">fn </span>remaining_block_len(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| COMPRESSION_BLOCK_SIZE - <span class="self">self</span>.block.len() |
| } |
| |
| <span class="doccomment">/// Writes all of the given positions delta. |
| </span><span class="kw">pub fn </span>write_positions_delta(<span class="kw-2">&mut </span><span class="self">self</span>, <span class="kw-2">mut </span>positions_delta: <span class="kw-2">&</span>[u32]) { |
| <span class="kw">while </span>!positions_delta.is_empty() { |
| <span class="kw">let </span>remaining_block_len = <span class="self">self</span>.remaining_block_len(); |
| <span class="kw">let </span>num_to_write = remaining_block_len.min(positions_delta.len()); |
| <span class="self">self</span>.block.extend(<span class="kw-2">&</span>positions_delta[..num_to_write]); |
| positions_delta = <span class="kw-2">&</span>positions_delta[num_to_write..]; |
| <span class="kw">if </span><span class="self">self</span>.remaining_block_len() == <span class="number">0 </span>{ |
| <span class="self">self</span>.flush_block(); |
| } |
| } |
| } |
| |
| <span class="kw">fn </span>flush_block(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="comment">// encode the positions in the block |
| </span><span class="kw">if </span><span class="self">self</span>.block.is_empty() { |
| <span class="kw">return</span>; |
| } |
| <span class="kw">if </span><span class="self">self</span>.block.len() == COMPRESSION_BLOCK_SIZE { |
| <span class="kw">let </span>(bit_width, block_encoded): (u8, <span class="kw-2">&</span>[u8]) = |
| <span class="self">self</span>.block_encoder.compress_block_unsorted(<span class="kw-2">&</span><span class="self">self</span>.block[..]); |
| <span class="self">self</span>.bit_widths.push(bit_width); |
| <span class="self">self</span>.positions_buffer.extend(block_encoded); |
| } <span class="kw">else </span>{ |
| <span class="macro">debug_assert!</span>(<span class="self">self</span>.block.len() < COMPRESSION_BLOCK_SIZE); |
| <span class="kw">let </span>block_vint_encoded = <span class="self">self</span>.block_encoder.compress_vint_unsorted(<span class="kw-2">&</span><span class="self">self</span>.block[..]); |
| <span class="self">self</span>.positions_buffer.extend_from_slice(block_vint_encoded); |
| } |
| <span class="self">self</span>.block.clear(); |
| } |
| |
| <span class="doccomment">/// Close the positions for the current term. |
| </span><span class="kw">pub fn </span>close_term(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<()> { |
| <span class="self">self</span>.flush_block(); |
| VInt(<span class="self">self</span>.bit_widths.len() <span class="kw">as </span>u64).serialize(<span class="kw-2">&mut </span><span class="self">self</span>.positions_wrt)<span class="question-mark">?</span>; |
| <span class="self">self</span>.positions_wrt.write_all(<span class="kw-2">&</span><span class="self">self</span>.bit_widths[..])<span class="question-mark">?</span>; |
| <span class="self">self</span>.positions_wrt.write_all(<span class="kw-2">&</span><span class="self">self</span>.positions_buffer)<span class="question-mark">?</span>; |
| <span class="self">self</span>.bit_widths.clear(); |
| <span class="self">self</span>.positions_buffer.clear(); |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="doccomment">/// Close the positions for this term and flushes the data. |
| </span><span class="kw">pub fn </span>close(<span class="kw-2">mut </span><span class="self">self</span>) -> io::Result<()> { |
| <span class="self">self</span>.positions_wrt.flush() |
| } |
| } |
| </code></pre></div> |
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