FEAT: ArrayList into num array

zig/read_input.zig

@@ -6,7 +6,11 @@ const expect = std.testing.expect;
 
 const MAX_SIZE = 1_000_000_000;
 
-pub fn split_lines(file_path: []const u8, allocator: mem.Allocator) !ArrayList([]const u8) {
+//
+// Takes an input file path, and returns a list with
+// the lines split by new line '\n'
+//
+pub fn splitLines(file_path: []const u8, allocator: mem.Allocator) !ArrayList([]const u8) {
     const file = try std.fs.cwd().openFile(file_path, .{});
     var content = try file.reader().readAllAlloc(allocator, MAX_SIZE);
 
@@ -20,9 +24,21 @@ pub fn split_lines(file_path: []const u8, allocator: mem.Allocator) !ArrayList([
     return lines;
 }
 
+//
+// Returns a slice the same size as `strings`
+// Can return an error if there's parsing issues with the string to int.
+//
+pub fn stringsToInt(strings: ArrayList([]const u8), allocator: mem.Allocator, base: u8) ![]i64 {
+    var ints = try allocator.alloc(i64, strings.items.len);
+    for (0..strings.items.len) |index| {
+        ints[index] = try std.fmt.parseInt(i64, strings.items[index], base);
+    }
+    return ints;
+}
+
 test "Reads file" {
     var test_alloc = std.heap.page_allocator;
-    var lines = try split_lines("test.txt", test_alloc);
+    var lines = try splitLines("test.txt", test_alloc);
 
     defer lines.deinit();
 
@@ -30,3 +46,20 @@ test "Reads file" {
     try expect(mem.eql(u8, lines.items[0], "hello"));
     try expect(mem.eql(u8, lines.items[1], "world"));
 }
+
+test "Takes strings into ints" {
+    var test_alloc = std.heap.page_allocator;
+    var stringList = ArrayList([]const u8).init(test_alloc);
+    defer stringList.deinit();
+
+    try stringList.append("10");
+    try stringList.append("12");
+    try stringList.append("987");
+
+    var nums = try stringsToInt(stringList, test_alloc, 10);
+
+    try expect(nums.len == 3);
+    try expect(nums[0] == 10);
+    try expect(nums[1] == 12);
+    try expect(nums[2] == 987);
+}