From efdce13757bf5e0cc86c6deab30176800d12c6bf Mon Sep 17 00:00:00 2001
From: Alex Wright <alex@xeentech.com>
Date: Sun, 18 Sep 2022 15:41:07 +0100
Subject: [PATCH] Basic reader for the ONS postcode CSV

---
 Cargo.toml  | 11 +++++++
 src/main.rs | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+)
 create mode 100644 Cargo.toml
 create mode 100644 src/main.rs

diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..e575f3f
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "postcodes"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+csv = "1.1.6"
+serde = { version = "1.0.145", features = ["derive"] }
+serde_repr = "0.1.9"
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..a0e20af
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,88 @@
+use csv::Reader;
+use csv::ReaderBuilder;
+use std::error::Error;
+use std::io;
+use std::process;
+use serde::{Deserialize, Serialize};
+use serde;
+use serde_repr::*;
+
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(rename_all = "lowercase")]
+enum Status {
+    Live,
+    Terminated,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(rename_all = "lowercase")]
+enum UserType {
+    Small,
+    Large,
+}
+
+#[derive(Serialize_repr, Deserialize_repr, PartialEq, Debug)]
+#[repr(u8)]
+enum PositionalQuality {
+    MatchedAddressPostcodeMean = 1,
+    LandlineMapsInspection = 2,
+    ApproximateWithin50Meters = 3,
+    PostcodeUnitMean = 4,
+    ImputedByONS = 5,
+    PostcodeSectorMean = 6,
+    TerminatedPriorToGridlink = 8,
+    NoGridReferenceAvailable = 9,
+//  1 Within the building of the matched address closest to the postcode mean.
+//  2 As for status value 1, except by visual inspection of Landline maps (Scotland only).
+//  3 Approximate to within 50 metres.
+//  4 Postcode unit mean (mean of matched addresses with the same postcode, but not snapped to a building).
+//  5 Imputed by ONS, by reference to surrounding postcode grid references.
+//  6 Postcode sector mean, (mainly PO Boxes).
+//  7 Not used.
+//  8 Postcode terminated prior to Gridlink® initiative, last known ONS postcode grid reference.
+//  9 No grid reference available.
+}
+
+#[derive(Debug, Deserialize)]
+struct Postcode {
+    postcode: String,
+    status: Status,
+    usertype: UserType,
+    #[serde(deserialize_with = "csv::invalid_option")]
+    easting: Option<u32>,
+    #[serde(deserialize_with = "csv::invalid_option")]
+    northing: Option<u32>,
+    positional_quality_indicator: PositionalQuality,
+    country: String,
+    latitude: Option<String>,
+    longitude: Option<String>,
+    postcode_no_space: String,
+    postcode_fixed_width_seven: String,
+    postcode_fixed_width_eight: String,
+    postcode_area: String,
+    postcode_district: String,
+    postcode_sector: String,
+    outcode: String,
+    incode: String,
+}
+
+fn read() -> Result<(), Box<dyn Error>> {
+    let mut rdr = ReaderBuilder::new()
+        .has_headers(false)
+        .from_reader(io::stdin());
+    let mut i: u32 = 0;
+    for result in rdr.deserialize() {
+        let record: Postcode = result?;
+        // println!("{}:: {:?}", i, record);
+        i += 1;
+    }
+    println!("Read {:?} postcodes", i);
+    Ok(())
+}
+
+fn main() {
+    if let Err(err) = read() {
+        println!("error running example: {}", err);
+        process::exit(1);
+    }
+}