parse artists.csv

1 files changed, 82 insertions, 0 deletions

diff --git a/CSVParser.cpp b/CSVParser.cpp
new file mode 100644
index 0000000..3fbe804
--- /dev/null
+++ b/CSVParser.cpp
@@ -0,0 +1,82 @@
+#include <cstdlib>
+#include <string>
+#include <sstream>
+#include <vector>
+#include <algorithm>
+
+#include "CSVParser.h"
+#include "Exception.h"
+#include "Parser.h"
+
+using namespace std;
+
+CSVParser CSVParser::instance {};
+CSVParser::CSVParser() {
+	Parser::register_strategy(this);
+}
+
+unsigned int CSVParser::heuristic(File & f) {
+	const string content = f.read();
+	int global_columns = 0;
+	int columns = 1;
+	int rows = 0;
+	int penalty = 1;
+	for (char c : content) {
+		if (c == ',') columns++;
+		if (c == '\n') {
+			rows++;
+			if (global_columns == 0) global_columns = columns;
+			penalty += abs(global_columns - columns);
+			columns = 1;
+		}
+	}
+	if (global_columns == 1) penalty += 1000;
+	return (rows + global_columns) / penalty;
+}
+
+static size_t header_idx(vector<string> header, string field) {
+	auto iter = find(header.begin(), header.end(), field);
+	if (iter == header.end())
+		throw Exception("CSV file is missing \"%s\" column", field.c_str());
+	return iter - header.begin();
+}
+
+void CSVParser::parse(File & f, Deserializer & d) {
+	vector<vector<string>> table = {};
+
+	istringstream rows(f.read());
+	string row;
+	while (getline(rows, row)) {
+		// ignore windows line endings
+		if (row.back() == '\r') row.pop_back();
+		istringstream columns(row);
+		string column;
+
+		vector<string> table_row = {};
+		while (getline(columns, column, ',')) {
+			table_row.push_back(column);
+		}
+		table.push_back(table_row);
+	}
+
+	if (table.size() < 1)
+		throw Exception("not enough data rows in CSV file");
+
+	vector<string> table_header = table[0];
+	table.erase(table.begin());
+
+	size_t x_idx = header_idx(table_header, "x");
+	size_t y_idx = header_idx(table_header, "y");
+	size_t vx_idx = header_idx(table_header, "vx");
+	size_t vy_idx = header_idx(table_header, "vy");
+
+	for (vector<string> row : table) {
+		d.add_artist({
+			.x = stof(row[x_idx]),
+			.y = stof(row[y_idx]),
+			.vx = stof(row[vx_idx]),
+			.vy = stof(row[vy_idx]),
+		});
+	}
+}
+