Implement stricter validation modes for CSP input

src/cli/convert.rs

@@ -47,6 +47,18 @@ pub struct SubcmdOptions {
 	/// Number of seats
 	#[clap(help_heading=Some("ELECTION SPECIFICATION"), long)]
 	seats: Option<usize>,
+	
+	/// Require 1st preference
+	#[clap(help_heading=Some("PREFERENCE VALIDATION"), long)]
+	require_1: bool,
+	
+	/// Require sequential preferences
+	#[clap(help_heading=Some("PREFERENCE VALIDATION"), long)]
+	require_sequential: bool,
+	
+	/// Require strict ordering of preferences
+	#[clap(help_heading=Some("PREFERENCE VALIDATION"), long)]
+	require_strict_order: bool,
 }
 
 /// Entrypoint for subcommand
@@ -97,7 +109,7 @@ pub fn main(mut cmd_opts: SubcmdOptions) -> Result<(), i32> {
 		}
 		"csp" => {
 			let file = File::open(cmd_opts.infile).expect("IO Error");
-			election = parser::csp::parse_reader(file);
+			election = parser::csp::parse_reader(file, cmd_opts.require_1, cmd_opts.require_sequential, cmd_opts.require_strict_order);
 		}
 		_ => unreachable!()
 	};

src/parser/csp.rs

@@ -25,7 +25,7 @@ use std::collections::HashMap;
 use std::io::Read;
 
 /// Parse the given CSP file
-pub fn parse_reader<R: Read, N: Number>(reader: R) -> Election<N> {
+pub fn parse_reader<R: Read, N: Number>(reader: R, require_1: bool, require_sequential: bool, require_strict_order: bool) -> Election<N> {
 	// Read CSV file
 	let mut reader = ReaderBuilder::new()
 		.has_headers(true)
@@ -86,13 +86,43 @@ pub fn parse_reader<R: Read, N: Number>(reader: R) -> Election<N> {
 		let mut unique_rankings: Vec<usize> = preferences.iter().map(|(r, _)| *r).unique().collect();
 		unique_rankings.sort();
 		
+		if require_1 {
+			if unique_rankings.first().map(|r| *r == 1).unwrap_or(false) == false {
+				// No #1 preference
+				ballots.push(Ballot {
+					orig_value: value,
+					preferences: vec![],
+				});
+				continue;
+			}
+		}
+		
 		let mut sorted_preferences = Vec::with_capacity(preferences.len());
+		let mut last_ranking = None;
 		for ranking in unique_rankings {
 			// Filter for preferences at this ranking
 			let prefs_this_ranking: Vec<usize> = preferences.iter()
 				.filter_map(|(r, i)| if *r == ranking { Some(**i) } else { None })
 				.collect();
+			
+			if require_strict_order {
+				if prefs_this_ranking.len() != 1 {
+					// Duplicate rankings
+					break;
+				}
+			}
+			
+			if require_sequential {
+				if let Some(r) = last_ranking {
+					if ranking != r + 1 {
+						// Not sequential
+						break;
+					}
+				}
+			}
+			
 			sorted_preferences.push(prefs_this_ranking);
+			last_ranking = Some(ranking);
 		}
 		
 		ballots.push(Ballot {