114 lines
3.0 KiB
Markdown
114 lines
3.0 KiB
Markdown
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csv-core
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========
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A fast CSV reader and write for use in a `no_std` context. This crate will
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never use the Rust standard library.
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[](https://travis-ci.org/BurntSushi/rust-csv)
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[](https://ci.appveyor.com/project/BurntSushi/rust-csv)
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[](https://crates.io/crates/csv-core)
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Dual-licensed under MIT or the [UNLICENSE](http://unlicense.org).
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### Documentation
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https://docs.rs/csv-core
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### Usage
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Add this to your `Cargo.toml`:
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```toml
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[dependencies]
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csv-core = "0.1.6"
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```
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### Build features
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This crate by default links with `libc`, which is done via the `libc` feature.
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Disabling this feature will drop `csv-core`'s dependency on `libc`.
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### Example: reading CSV
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This example shows how to count the number of fields and records in CSV data.
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```rust
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use csv_core::{Reader, ReadFieldResult};
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let data = "
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foo,bar,baz
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a,b,c
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xxx,yyy,zzz
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";
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let mut rdr = Reader::new();
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let mut bytes = data.as_bytes();
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let mut count_fields = 0;
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let mut count_records = 0;
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loop {
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// We skip handling the output since we don't need it for counting.
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let (result, nin, _) = rdr.read_field(bytes, &mut [0; 1024]);
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bytes = &bytes[nin..];
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match result {
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ReadFieldResult::InputEmpty => {},
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ReadFieldResult::OutputFull => panic!("field too large"),
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ReadFieldResult::Field { record_end } => {
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count_fields += 1;
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if record_end {
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count_records += 1;
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}
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}
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ReadFieldResult::End => break,
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}
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}
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assert_eq!(3, count_records);
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assert_eq!(9, count_fields);
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```
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### Example: writing CSV
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This example shows how to use the `Writer` API to write valid CSV data. Proper
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quoting is handled automatically.
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```rust
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use csv_core::Writer;
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// This is where we'll write out CSV data.
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let mut out = &mut [0; 1024];
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// The number of bytes we've written to `out`.
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let mut nout = 0;
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// Create a CSV writer with a default configuration.
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let mut wtr = Writer::new();
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// Write a single field. Note that we ignore the `WriteResult` and the number
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// of input bytes consumed since we're doing this by hand.
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let (_, _, n) = wtr.field(&b"foo"[..], &mut out[nout..]);
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nout += n;
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// Write a delimiter and then another field that requires quotes.
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let (_, n) = wtr.delimiter(&mut out[nout..]);
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nout += n;
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let (_, _, n) = wtr.field(&b"bar,baz"[..], &mut out[nout..]);
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nout += n;
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let (_, n) = wtr.terminator(&mut out[nout..]);
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nout += n;
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// Now write another record.
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let (_, _, n) = wtr.field(&b"a \"b\" c"[..], &mut out[nout..]);
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nout += n;
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let (_, n) = wtr.delimiter(&mut out[nout..]);
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nout += n;
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let (_, _, n) = wtr.field(&b"quux"[..], &mut out[nout..]);
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nout += n;
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// We must always call finish once done writing.
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// This ensures that any closing quotes are written.
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let (_, n) = wtr.finish(&mut out[nout..]);
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nout += n;
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assert_eq!(&out[..nout], &b"\
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foo,\"bar,baz\"
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\"a \"\"b\"\" c\",quux"[..]);
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```
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