Small input utility.

2019/src/day12.cpp

@@ -1,7 +1,6 @@
 #include <iostream>
 #include <numeric>
 #include <vector>
-#include <regex>
 #include "days.hpp"
 #include "point.hpp"
 
@@ -12,18 +11,10 @@ namespace {
     std::vector<point_t> read_moons(std::istream &input) {
         std::vector<point_t> moons;
 
-        std::regex regex(R"(^<x=(-?\d+), y=(-?\d+), z=(-?\d+)>$)");
-        std::smatch results;
+        point_t moon;
 
-        for (std::string buffer; std::getline(input, buffer);) {
-            if (!std::regex_match(buffer, results, regex)) {
-                throw std::domain_error(buffer);
-            }
-
-            point_t moon;
-            for (int i = 0; i < 3; ++i) from_chars(results[i + 1].str(), moon[i]);
-
-            moons.emplace_back(moon);
+        while (aoc2019::read_line_numbers_and_garbage<int>(input, moon.begin())) {
+            moons.push_back(moon);
         }
 
         return moons;

2019/src/utils.hpp

@@ -21,6 +21,25 @@ namespace aoc2019 {
         seed ^= hash(o) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
     }
 
+    template<typename ValueType, typename OutputIt>
+    std::istream &read_line_numbers_and_garbage(std::istream &input, OutputIt output) {
+        ValueType v;
+        char c;
+        while (input && (c = input.peek()) != '\n') {
+            if (c == '-' || std::isdigit(c)) {
+                input >> v;
+                *output = v;
+                ++output;
+            } else {
+                input.ignore();
+            }
+        }
+
+        input.get();
+
+        return input;
+    }
+
     std::string_view strtok(std::string_view &str, char token = ',');
 
     std::deque<int64_t> run_intcode(std::vector<std::int64_t> program, std::deque<std::int64_t> inputs = {});