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</pre><pre class="rust"><code><span class="comment">// Copyright (C) 2022 Quickwit, Inc.
//
// Quickwit is offered under the AGPL v3.0 and as commercial software.
// For commercial licensing, contact us at hello@quickwit.io.
//
// AGPL:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see &lt;http://www.gnu.org/licenses/&gt;.
</span><span class="kw">use </span>std::num::NonZeroU64;
<span class="kw">use </span>std::sync::Arc;
<span class="kw">use </span>std::{fmt, io};
<span class="kw">use </span>common::{BinarySerializable, VInt};
<span class="kw">use </span>log::warn;
<span class="kw">use </span>ownedbytes::OwnedBytes;
<span class="kw">use </span><span class="kw">crate</span>::bitpacked::BitpackedCodec;
<span class="kw">use </span><span class="kw">crate</span>::blockwise_linear::BlockwiseLinearCodec;
<span class="kw">use </span><span class="kw">crate</span>::compact_space::CompactSpaceCompressor;
<span class="kw">use </span><span class="kw">crate</span>::format_version::append_format_version;
<span class="kw">use </span><span class="kw">crate</span>::linear::LinearCodec;
<span class="kw">use </span><span class="kw">crate</span>::monotonic_mapping::{
StrictlyMonotonicFn, StrictlyMonotonicMappingToInternal,
StrictlyMonotonicMappingToInternalGCDBaseval,
};
<span class="kw">use </span><span class="kw">crate</span>::null_index_footer::{
append_null_index_footer, FastFieldCardinality, NullIndexCodec, NullIndexFooter,
};
<span class="kw">use crate</span>::{
monotonic_map_column, Column, FastFieldCodec, FastFieldCodecType, MonotonicallyMappableToU64,
U128FastFieldCodecType, VecColumn, ALL_CODEC_TYPES,
};
<span class="doccomment">/// The normalized header gives some parameters after applying the following
/// normalization of the vector:
/// `val -&gt; (val - min_value) / gcd`
///
/// By design, after normalization, `min_value = 0` and `gcd = 1`.
</span><span class="attribute">#[derive(Debug, Copy, Clone)]
</span><span class="kw">pub struct </span>NormalizedHeader {
<span class="doccomment">/// The number of values in the underlying column.
</span><span class="kw">pub </span>num_vals: u32,
<span class="doccomment">/// The max value of the underlying column.
</span><span class="kw">pub </span>max_value: u64,
}
<span class="attribute">#[derive(Debug, Copy, Clone)]
</span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>Header {
<span class="kw">pub </span>num_vals: u32,
<span class="kw">pub </span>min_value: u64,
<span class="kw">pub </span>max_value: u64,
<span class="kw">pub </span>gcd: <span class="prelude-ty">Option</span>&lt;NonZeroU64&gt;,
<span class="kw">pub </span>codec_type: FastFieldCodecType,
}
<span class="kw">impl </span>Header {
<span class="kw">pub fn </span>normalized(<span class="self">self</span>) -&gt; NormalizedHeader {
<span class="kw">let </span>gcd = <span class="self">self</span>.gcd.map(|gcd| gcd.get()).unwrap_or(<span class="number">1</span>);
<span class="kw">let </span>gcd_min_val_mapping =
StrictlyMonotonicMappingToInternalGCDBaseval::new(gcd, <span class="self">self</span>.min_value);
<span class="kw">let </span>max_value = gcd_min_val_mapping.mapping(<span class="self">self</span>.max_value);
NormalizedHeader {
num_vals: <span class="self">self</span>.num_vals,
max_value,
}
}
<span class="kw">pub fn </span>normalize_column&lt;C: Column&gt;(<span class="kw-2">&amp;</span><span class="self">self</span>, from_column: C) -&gt; <span class="kw">impl </span>Column {
normalize_column(from_column, <span class="self">self</span>.min_value, <span class="self">self</span>.gcd)
}
<span class="kw">pub fn </span>compute_header(
column: <span class="kw">impl </span>Column&lt;u64&gt;,
codecs: <span class="kw-2">&amp;</span>[FastFieldCodecType],
) -&gt; <span class="prelude-ty">Option</span>&lt;Header&gt; {
<span class="kw">let </span>num_vals = column.num_vals();
<span class="kw">let </span>min_value = column.min_value();
<span class="kw">let </span>max_value = column.max_value();
<span class="kw">let </span>gcd = <span class="kw">crate</span>::gcd::find_gcd(column.iter().map(|val| val - min_value))
.filter(|gcd| gcd.get() &gt; <span class="number">1u64</span>);
<span class="kw">let </span>normalized_column = normalize_column(column, min_value, gcd);
<span class="kw">let </span>codec_type = detect_codec(normalized_column, codecs)<span class="question-mark">?</span>;
<span class="prelude-val">Some</span>(Header {
num_vals,
min_value,
max_value,
gcd,
codec_type,
})
}
}
<span class="attribute">#[derive(Debug, Copy, Clone, PartialEq, Eq)]
</span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>U128Header {
<span class="kw">pub </span>num_vals: u32,
<span class="kw">pub </span>codec_type: U128FastFieldCodecType,
}
<span class="kw">impl </span>BinarySerializable <span class="kw">for </span>U128Header {
<span class="kw">fn </span>serialize&lt;W: io::Write&gt;(<span class="kw-2">&amp;</span><span class="self">self</span>, writer: <span class="kw-2">&amp;mut </span>W) -&gt; io::Result&lt;()&gt; {
VInt(<span class="self">self</span>.num_vals <span class="kw">as </span>u64).serialize(writer)<span class="question-mark">?</span>;
<span class="self">self</span>.codec_type.serialize(writer)<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(())
}
<span class="kw">fn </span>deserialize&lt;R: io::Read&gt;(reader: <span class="kw-2">&amp;mut </span>R) -&gt; io::Result&lt;<span class="self">Self</span>&gt; {
<span class="kw">let </span>num_vals = VInt::deserialize(reader)<span class="question-mark">?</span>.<span class="number">0 </span><span class="kw">as </span>u32;
<span class="kw">let </span>codec_type = U128FastFieldCodecType::deserialize(reader)<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(U128Header {
num_vals,
codec_type,
})
}
}
<span class="kw">pub fn </span>normalize_column&lt;C: Column&gt;(
from_column: C,
min_value: u64,
gcd: <span class="prelude-ty">Option</span>&lt;NonZeroU64&gt;,
) -&gt; <span class="kw">impl </span>Column {
<span class="kw">let </span>gcd = gcd.map(|gcd| gcd.get()).unwrap_or(<span class="number">1</span>);
<span class="kw">let </span>mapping = StrictlyMonotonicMappingToInternalGCDBaseval::new(gcd, min_value);
monotonic_map_column(from_column, mapping)
}
<span class="kw">impl </span>BinarySerializable <span class="kw">for </span>Header {
<span class="kw">fn </span>serialize&lt;W: io::Write&gt;(<span class="kw-2">&amp;</span><span class="self">self</span>, writer: <span class="kw-2">&amp;mut </span>W) -&gt; io::Result&lt;()&gt; {
VInt(<span class="self">self</span>.num_vals <span class="kw">as </span>u64).serialize(writer)<span class="question-mark">?</span>;
VInt(<span class="self">self</span>.min_value).serialize(writer)<span class="question-mark">?</span>;
VInt(<span class="self">self</span>.max_value - <span class="self">self</span>.min_value).serialize(writer)<span class="question-mark">?</span>;
<span class="kw">if let </span><span class="prelude-val">Some</span>(gcd) = <span class="self">self</span>.gcd {
VInt(gcd.get()).serialize(writer)<span class="question-mark">?</span>;
} <span class="kw">else </span>{
VInt(<span class="number">0u64</span>).serialize(writer)<span class="question-mark">?</span>;
}
<span class="self">self</span>.codec_type.serialize(writer)<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(())
}
<span class="kw">fn </span>deserialize&lt;R: io::Read&gt;(reader: <span class="kw-2">&amp;mut </span>R) -&gt; io::Result&lt;<span class="self">Self</span>&gt; {
<span class="kw">let </span>num_vals = VInt::deserialize(reader)<span class="question-mark">?</span>.<span class="number">0 </span><span class="kw">as </span>u32;
<span class="kw">let </span>min_value = VInt::deserialize(reader)<span class="question-mark">?</span>.<span class="number">0</span>;
<span class="kw">let </span>amplitude = VInt::deserialize(reader)<span class="question-mark">?</span>.<span class="number">0</span>;
<span class="kw">let </span>max_value = min_value + amplitude;
<span class="kw">let </span>gcd_u64 = VInt::deserialize(reader)<span class="question-mark">?</span>.<span class="number">0</span>;
<span class="kw">let </span>codec_type = FastFieldCodecType::deserialize(reader)<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(Header {
num_vals,
min_value,
max_value,
gcd: NonZeroU64::new(gcd_u64),
codec_type,
})
}
}
<span class="doccomment">/// Return estimated compression for given codec in the value range [0.0..1.0], where 1.0 means no
/// compression.
</span><span class="kw">pub fn </span>estimate&lt;T: MonotonicallyMappableToU64 + fmt::Debug&gt;(
typed_column: <span class="kw">impl </span>Column&lt;T&gt;,
codec_type: FastFieldCodecType,
) -&gt; <span class="prelude-ty">Option</span>&lt;f32&gt; {
<span class="kw">let </span>column = monotonic_map_column(typed_column, StrictlyMonotonicMappingToInternal::&lt;T&gt;::new());
<span class="kw">let </span>min_value = column.min_value();
<span class="kw">let </span>gcd = <span class="kw">crate</span>::gcd::find_gcd(column.iter().map(|val| val - min_value))
.filter(|gcd| gcd.get() &gt; <span class="number">1u64</span>);
<span class="kw">let </span>mapping = StrictlyMonotonicMappingToInternalGCDBaseval::new(
gcd.map(|gcd| gcd.get()).unwrap_or(<span class="number">1u64</span>),
min_value,
);
<span class="kw">let </span>normalized_column = monotonic_map_column(<span class="kw-2">&amp;</span>column, mapping);
<span class="kw">match </span>codec_type {
FastFieldCodecType::Bitpacked =&gt; BitpackedCodec::estimate(<span class="kw-2">&amp;</span>normalized_column),
FastFieldCodecType::Linear =&gt; LinearCodec::estimate(<span class="kw-2">&amp;</span>normalized_column),
FastFieldCodecType::BlockwiseLinear =&gt; BlockwiseLinearCodec::estimate(<span class="kw-2">&amp;</span>normalized_column),
}
}
<span class="doccomment">/// Serializes u128 values with the compact space codec.
</span><span class="kw">pub fn </span>serialize_u128&lt;F: Fn() -&gt; I, I: Iterator&lt;Item = u128&gt;&gt;(
iter_gen: F,
num_vals: u32,
output: <span class="kw-2">&amp;mut </span><span class="kw">impl </span>io::Write,
) -&gt; io::Result&lt;()&gt; {
<span class="kw">let </span>header = U128Header {
num_vals,
codec_type: U128FastFieldCodecType::CompactSpace,
};
header.serialize(output)<span class="question-mark">?</span>;
<span class="kw">let </span>compressor = CompactSpaceCompressor::train_from(iter_gen(), num_vals);
compressor.compress_into(iter_gen(), output).unwrap();
<span class="kw">let </span>null_index_footer = NullIndexFooter {
cardinality: FastFieldCardinality::Single,
null_index_codec: NullIndexCodec::Full,
null_index_byte_range: <span class="number">0</span>..<span class="number">0</span>,
};
append_null_index_footer(output, null_index_footer)<span class="question-mark">?</span>;
append_format_version(output)<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(())
}
<span class="doccomment">/// Serializes the column with the codec with the best estimate on the data.
</span><span class="kw">pub fn </span>serialize&lt;T: MonotonicallyMappableToU64 + fmt::Debug&gt;(
typed_column: <span class="kw">impl </span>Column&lt;T&gt;,
output: <span class="kw-2">&amp;mut </span><span class="kw">impl </span>io::Write,
codecs: <span class="kw-2">&amp;</span>[FastFieldCodecType],
) -&gt; io::Result&lt;()&gt; {
<span class="kw">let </span>column = monotonic_map_column(typed_column, StrictlyMonotonicMappingToInternal::&lt;T&gt;::new());
<span class="kw">let </span>header = Header::compute_header(<span class="kw-2">&amp;</span>column, codecs).ok_or_else(|| {
io::Error::new(
io::ErrorKind::InvalidInput,
<span class="macro">format!</span>(
<span class="string">&quot;Data cannot be serialized with this list of codec. {:?}&quot;</span>,
codecs
),
)
})<span class="question-mark">?</span>;
header.serialize(output)<span class="question-mark">?</span>;
<span class="kw">let </span>normalized_column = header.normalize_column(column);
<span class="macro">assert_eq!</span>(normalized_column.min_value(), <span class="number">0u64</span>);
serialize_given_codec(normalized_column, header.codec_type, output)<span class="question-mark">?</span>;
<span class="kw">let </span>null_index_footer = NullIndexFooter {
cardinality: FastFieldCardinality::Single,
null_index_codec: NullIndexCodec::Full,
null_index_byte_range: <span class="number">0</span>..<span class="number">0</span>,
};
append_null_index_footer(output, null_index_footer)<span class="question-mark">?</span>;
append_format_version(output)<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(())
}
<span class="kw">fn </span>detect_codec(
column: <span class="kw">impl </span>Column&lt;u64&gt;,
codecs: <span class="kw-2">&amp;</span>[FastFieldCodecType],
) -&gt; <span class="prelude-ty">Option</span>&lt;FastFieldCodecType&gt; {
<span class="kw">let </span><span class="kw-2">mut </span>estimations = Vec::new();
<span class="kw">for </span><span class="kw-2">&amp;</span>codec <span class="kw">in </span>codecs {
<span class="kw">let </span>estimation_opt = <span class="kw">match </span>codec {
FastFieldCodecType::Bitpacked =&gt; BitpackedCodec::estimate(<span class="kw-2">&amp;</span>column),
FastFieldCodecType::Linear =&gt; LinearCodec::estimate(<span class="kw-2">&amp;</span>column),
FastFieldCodecType::BlockwiseLinear =&gt; BlockwiseLinearCodec::estimate(<span class="kw-2">&amp;</span>column),
};
<span class="kw">if let </span><span class="prelude-val">Some</span>(estimation) = estimation_opt {
estimations.push((estimation, codec));
}
}
<span class="kw">if let </span><span class="prelude-val">Some</span>(broken_estimation) = estimations.iter().find(|estimation| estimation.<span class="number">0</span>.is_nan()) {
<span class="macro">warn!</span>(
<span class="string">&quot;broken estimation for fast field codec {:?}&quot;</span>,
broken_estimation.<span class="number">1
</span>);
}
<span class="comment">// removing nan values for codecs with broken calculations, and max values which disables
// codecs
</span>estimations.retain(|estimation| !estimation.<span class="number">0</span>.is_nan() &amp;&amp; estimation.<span class="number">0 </span>!= f32::MAX);
estimations.sort_by(|(score_left, <span class="kw">_</span>), (score_right, <span class="kw">_</span>)| score_left.total_cmp(score_right));
<span class="prelude-val">Some</span>(estimations.first()<span class="question-mark">?</span>.<span class="number">1</span>)
}
<span class="kw">fn </span>serialize_given_codec(
column: <span class="kw">impl </span>Column&lt;u64&gt;,
codec_type: FastFieldCodecType,
output: <span class="kw-2">&amp;mut </span><span class="kw">impl </span>io::Write,
) -&gt; io::Result&lt;()&gt; {
<span class="kw">match </span>codec_type {
FastFieldCodecType::Bitpacked =&gt; {
BitpackedCodec::serialize(<span class="kw-2">&amp;</span>column, output)<span class="question-mark">?</span>;
}
FastFieldCodecType::Linear =&gt; {
LinearCodec::serialize(<span class="kw-2">&amp;</span>column, output)<span class="question-mark">?</span>;
}
FastFieldCodecType::BlockwiseLinear =&gt; {
BlockwiseLinearCodec::serialize(<span class="kw-2">&amp;</span>column, output)<span class="question-mark">?</span>;
}
}
output.flush()<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(())
}
<span class="doccomment">/// Helper function to serialize a column (autodetect from all codecs) and then open it
</span><span class="kw">pub fn </span>serialize_and_load&lt;T: MonotonicallyMappableToU64 + Ord + Default + fmt::Debug&gt;(
column: <span class="kw-2">&amp;</span>[T],
) -&gt; Arc&lt;<span class="kw">dyn </span>Column&lt;T&gt;&gt; {
<span class="kw">let </span><span class="kw-2">mut </span>buffer = Vec::new();
<span class="kw">super</span>::serialize(VecColumn::from(<span class="kw-2">&amp;</span>column), <span class="kw-2">&amp;mut </span>buffer, <span class="kw-2">&amp;</span>ALL_CODEC_TYPES).unwrap();
<span class="kw">super</span>::open(OwnedBytes::new(buffer)).unwrap()
}
<span class="attribute">#[cfg(test)]
</span><span class="kw">mod </span>tests {
<span class="kw">use super</span>::<span class="kw-2">*</span>;
<span class="attribute">#[test]
</span><span class="kw">fn </span>test_serialize_deserialize_u128_header() {
<span class="kw">let </span>original = U128Header {
num_vals: <span class="number">11</span>,
codec_type: U128FastFieldCodecType::CompactSpace,
};
<span class="kw">let </span><span class="kw-2">mut </span>out = Vec::new();
original.serialize(<span class="kw-2">&amp;mut </span>out).unwrap();
<span class="kw">let </span>restored = U128Header::deserialize(<span class="kw-2">&amp;mut &amp;</span>out[..]).unwrap();
<span class="macro">assert_eq!</span>(restored, original);
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>test_serialize_deserialize() {
<span class="kw">let </span>original = [<span class="number">1u64</span>, <span class="number">5u64</span>, <span class="number">10u64</span>];
<span class="kw">let </span>restored: Vec&lt;u64&gt; = serialize_and_load(<span class="kw-2">&amp;</span>original[..]).iter().collect();
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>restored, <span class="kw-2">&amp;</span>original[..]);
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>test_fastfield_bool_size_bitwidth_1() {
<span class="kw">let </span><span class="kw-2">mut </span>buffer = Vec::new();
<span class="kw">let </span>col = VecColumn::from(<span class="kw-2">&amp;</span>[<span class="bool-val">false</span>, <span class="bool-val">true</span>][..]);
serialize(col, <span class="kw-2">&amp;mut </span>buffer, <span class="kw-2">&amp;</span>ALL_CODEC_TYPES).unwrap();
<span class="comment">// 5 bytes of header, 1 byte of value, 7 bytes of padding.
</span><span class="macro">assert_eq!</span>(buffer.len(), <span class="number">3 </span>+ <span class="number">5 </span>+ <span class="number">8 </span>+ <span class="number">4 </span>+ <span class="number">2</span>);
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>test_fastfield_bool_bit_size_bitwidth_0() {
<span class="kw">let </span><span class="kw-2">mut </span>buffer = Vec::new();
<span class="kw">let </span>col = VecColumn::from(<span class="kw-2">&amp;</span>[<span class="bool-val">true</span>][..]);
serialize(col, <span class="kw-2">&amp;mut </span>buffer, <span class="kw-2">&amp;</span>ALL_CODEC_TYPES).unwrap();
<span class="comment">// 5 bytes of header, 0 bytes of value, 7 bytes of padding.
</span><span class="macro">assert_eq!</span>(buffer.len(), <span class="number">3 </span>+ <span class="number">5 </span>+ <span class="number">7 </span>+ <span class="number">4 </span>+ <span class="number">2</span>);
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>test_fastfield_gcd() {
<span class="kw">let </span><span class="kw-2">mut </span>buffer = Vec::new();
<span class="kw">let </span>vals: Vec&lt;u64&gt; = (<span class="number">0</span>..<span class="number">80</span>).map(|val| (val % <span class="number">7</span>) * <span class="number">1_000u64</span>).collect();
<span class="kw">let </span>col = VecColumn::from(<span class="kw-2">&amp;</span>vals[..]);
serialize(col, <span class="kw-2">&amp;mut </span>buffer, <span class="kw-2">&amp;</span>[FastFieldCodecType::Bitpacked]).unwrap();
<span class="comment">// Values are stored over 3 bits.
</span><span class="macro">assert_eq!</span>(buffer.len(), <span class="number">3 </span>+ <span class="number">7 </span>+ (<span class="number">3 </span>* <span class="number">80 </span>/ <span class="number">8</span>) + <span class="number">7 </span>+ <span class="number">4 </span>+ <span class="number">2</span>);
}
}
</code></pre></div>
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