toy bracket counter in zig

bracket_count.zig

const std = @import("std");
const process = std.process;
const stdout = std.io.getStdOut();
//const log = std.log;

const usage: []const u8 =
    \\Usage: bracket_count file1 file2 ..
;

pub fn main() !void {
    // 1. read file names from cli args
    var arena_instance = std.heap.ArenaAllocator.init(std.heap.page_allocator);
    defer arena_instance.deinit();
    const arena = arena_instance.allocator();
    const args: [][:0]u8 = try process.argsAlloc(arena);
    defer process.argsFree(arena, args);
    if (args.len <= 1) {
        try stdout.writer().print("{s}\n", .{usage});
    }
    // 2. count {,} [,], (,) to check, if counter has become negative
    // output usable for vim
    var i: u64 = 1; // skip program name
    while (i < args.len) : (i += 1) {
        //log.debug("reading file {s}..\n", .{args[i]});
        const read_contents = try std.fs.cwd().readFileAlloc(arena, args[i], 1024 * 1024);
        defer arena.free(read_contents);
        //log.debug("size: {d}\n", .{read_contents.len});
        //log.debug("{s}\n", .{read_contents});
        var line_nr: u64 = 0;
        var line_offset: u64 = 0;
        var counter_curly: i64 = 0;
        var counter_edgy: i64 = 0;
        var counter_round: i64 = 0;
        for (read_contents) |char| {
            if (char == '\n') {
                line_nr += 1;
                line_offset = 0;
            }
            line_offset += 1;
            switch (char) {
                '{' => {
                    counter_curly += 1;
                },
                '}' => {
                    counter_curly -= 1;
                },
                '[' => {
                    counter_edgy += 1;
                },
                ']' => {
                    counter_edgy -= 1;
                },
                '(' => {
                    counter_round += 1;
                },
                ')' => {
                    counter_round -= 1;
                },
                else => {},
            }
            // counter < 0 => increase counter to prevent spamming the same message
            if (counter_curly < 0) {
                try stdout.writer().print("too many closing {{}}-brackets\n{s}:{d}:{d}\n", .{ args[i], line_nr, line_offset });
                counter_curly += 1;
            }
            if (counter_edgy < 0) {
                try stdout.writer().print("too many closing []-brackets\n{s}:{d}:{d}\n", .{ args[i], line_nr, line_offset });
                counter_edgy += 1;
            }
            if (counter_round < 0) {
                try stdout.writer().print("too many closing ()-brackets\n{s}:{d}:{d}\n", .{ args[i], line_nr, line_offset });
                counter_round += 1;
            }
        }
        if (counter_curly < 0) try stdout.writer().print("too many closing {{}}-brackets\n{s}:{d}\n", .{ args[i], line_nr });
        if (counter_curly > 0) try stdout.writer().print("too few closing {{}}-brackets\n{s}:{d}\n", .{ args[i], line_nr });
        if (counter_edgy < 0) try stdout.writer().print("too many closing []-brackets\n{s}:{d}\n", .{ args[i], line_nr });
        if (counter_edgy > 0) try stdout.writer().print("too few closing []-brackets\n{s}:{d}\n", .{ args[i], line_nr });
        if (counter_round < 0) try stdout.writer().print("too many closing ()-brackets\n{s}:{d}\n", .{ args[i], line_nr });
        if (counter_round > 0) try stdout.writer().print("too few closing ()-brackets\n{s}:{d}\n", .{ args[i], line_nr });
    }
}