arrow_avro/
compression.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use arrow_schema::ArrowError;
19use std::io;
20use std::io::Read;
21
22/// The metadata key used for storing the JSON encoded [`CompressionCodec`]
23pub const CODEC_METADATA_KEY: &str = "avro.codec";
24
25#[derive(Debug, Copy, Clone, Eq, PartialEq)]
26pub enum CompressionCodec {
27    Deflate,
28    Snappy,
29    ZStandard,
30}
31
32impl CompressionCodec {
33    pub(crate) fn decompress(&self, block: &[u8]) -> Result<Vec<u8>, ArrowError> {
34        match self {
35            #[cfg(feature = "deflate")]
36            CompressionCodec::Deflate => {
37                let mut decoder = flate2::read::DeflateDecoder::new(block);
38                let mut out = Vec::new();
39                decoder.read_to_end(&mut out)?;
40                Ok(out)
41            }
42            #[cfg(not(feature = "deflate"))]
43            CompressionCodec::Deflate => Err(ArrowError::ParseError(
44                "Deflate codec requires deflate feature".to_string(),
45            )),
46            #[cfg(feature = "snappy")]
47            CompressionCodec::Snappy => {
48                // Each compressed block is followed by the 4-byte, big-endian CRC32
49                // checksum of the uncompressed data in the block.
50                let crc = &block[block.len() - 4..];
51                let block = &block[..block.len() - 4];
52
53                let mut decoder = snap::raw::Decoder::new();
54                let decoded = decoder
55                    .decompress_vec(block)
56                    .map_err(|e| ArrowError::ExternalError(Box::new(e)))?;
57
58                let checksum = crc::Crc::<u32>::new(&crc::CRC_32_ISO_HDLC).checksum(&decoded);
59                if checksum != u32::from_be_bytes(crc.try_into().unwrap()) {
60                    return Err(ArrowError::ParseError("Snappy CRC mismatch".to_string()));
61                }
62                Ok(decoded)
63            }
64            #[cfg(not(feature = "snappy"))]
65            CompressionCodec::Snappy => Err(ArrowError::ParseError(
66                "Snappy codec requires snappy feature".to_string(),
67            )),
68
69            #[cfg(feature = "zstd")]
70            CompressionCodec::ZStandard => {
71                let mut decoder = zstd::Decoder::new(block)?;
72                let mut out = Vec::new();
73                decoder.read_to_end(&mut out)?;
74                Ok(out)
75            }
76            #[cfg(not(feature = "zstd"))]
77            CompressionCodec::ZStandard => Err(ArrowError::ParseError(
78                "ZStandard codec requires zstd feature".to_string(),
79            )),
80        }
81    }
82}
arrow_avro/compression.rs

arrow_avro/
compression.rs
