46 lines
1.6 KiB
Rust
46 lines
1.6 KiB
Rust
use crate::varint::parse_varint;
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use anyhow::{bail, Result};
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/// Reads SQLite's "Record Format" as mentioned here:
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/// [record_format](https://www.sqlite.org/fileformat.html#record_format)
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pub fn parse_record(stream: &[u8], column_count: usize) -> Result<Vec<Vec<u8>>> {
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// Parse number of bytes in header, and use bytes_read as offset
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let (_, mut offset) = parse_varint(stream);
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// Read each varint into serial types and modify the offset
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let mut serial_types = vec![];
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for _ in 0..column_count {
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let (varint, read_bytes) = parse_varint(&stream[offset..]);
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offset += read_bytes;
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serial_types.push(varint);
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}
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// Parse each serial type as column into record and modify the offset
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let mut record = vec![];
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for serial_type in serial_types {
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let column = parse_column_value(&stream[offset..], serial_type as usize)?;
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offset += column.len();
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record.push(column);
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}
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Ok(record)
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}
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fn parse_column_value(stream: &[u8], serial_type: usize) -> Result<Vec<u8>> {
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let column_value = match serial_type {
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// 8 bit twos-complement integer
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1 => vec![stream[0]],
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// Text encoding
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n if serial_type >= 12 && serial_type % 2 == 0 => {
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let n_bytes = (n - 12) / 2;
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stream[0..n_bytes as usize].to_vec()
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}
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n if serial_type >= 13 && serial_type % 2 == 1 => {
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let n_bytes = (n - 13) / 2;
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stream[0..n_bytes as usize].to_vec()
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}
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_ => bail!("Invalid serial_type: {}", serial_type),
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};
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Ok(column_value)
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}
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