70 lines
1.9 KiB
Zig
70 lines
1.9 KiB
Zig
const std = @import("std");
|
|
const io = std.io;
|
|
const mem = std.mem;
|
|
const os = std.os;
|
|
const warn = std.debug.warn;
|
|
const allocator = std.debug.global_allocator;
|
|
|
|
pub fn main() !void {
|
|
var args_it = os.args();
|
|
const exe = try unwrapArg(??args_it.next(allocator));
|
|
var catted_anything = false;
|
|
var stdout_file = try io.getStdOut();
|
|
|
|
while (args_it.next(allocator)) |arg_or_err| {
|
|
const arg = try unwrapArg(arg_or_err);
|
|
if (mem.eql(u8, arg, "-")) {
|
|
catted_anything = true;
|
|
var stdin_file = try io.getStdIn();
|
|
try cat_file(&stdout_file, &stdin_file);
|
|
} else if (arg[0] == '-') {
|
|
return usage(exe);
|
|
} else {
|
|
var file = os.File.openRead(allocator, arg) catch |err| {
|
|
warn("Unable to open file: {}\n", @errorName(err));
|
|
return err;
|
|
};
|
|
defer file.close();
|
|
|
|
catted_anything = true;
|
|
try cat_file(&stdout_file, &file);
|
|
}
|
|
}
|
|
if (!catted_anything) {
|
|
var stdin_file = try io.getStdIn();
|
|
try cat_file(&stdout_file, &stdin_file);
|
|
}
|
|
}
|
|
|
|
fn usage(exe: []const u8) !void {
|
|
warn("Usage: {} [FILE]...\n", exe);
|
|
return error.Invalid;
|
|
}
|
|
|
|
fn cat_file(stdout: *os.File, file: *os.File) !void {
|
|
var buf: [1024 * 4]u8 = undefined;
|
|
|
|
while (true) {
|
|
const bytes_read = file.read(buf[0..]) catch |err| {
|
|
warn("Unable to read from stream: {}\n", @errorName(err));
|
|
return err;
|
|
};
|
|
|
|
if (bytes_read == 0) {
|
|
break;
|
|
}
|
|
|
|
stdout.write(buf[0..bytes_read]) catch |err| {
|
|
warn("Unable to write to stdout: {}\n", @errorName(err));
|
|
return err;
|
|
};
|
|
}
|
|
}
|
|
|
|
fn unwrapArg(arg: error![]u8) ![]u8 {
|
|
return arg catch |err| {
|
|
warn("Unable to parse command line: {}\n", err);
|
|
return err;
|
|
};
|
|
}
|