zig/std/std.zig

106 lines
2.7 KiB
Zig

use "syscall.zig";
const stdin_fileno : isize = 0;
const stdout_fileno : isize = 1;
const stderr_fileno : isize = 2;
// TODO error handling
pub fn os_get_random_bytes(buf: &u8, count: usize) -> isize {
getrandom(buf, count, 0)
}
// TODO error handling
// TODO handle buffering and flushing (mutex protected)
pub fn print_str(str: []const u8) -> isize {
fprint_str(stdout_fileno, str)
}
// TODO error handling
// TODO handle buffering and flushing (mutex protected)
pub fn fprint_str(fd: isize, str: []const u8) -> isize {
write(fd, str.ptr, str.len)
}
// TODO handle buffering and flushing (mutex protected)
// TODO error handling
pub fn print_u64(x: u64) -> isize {
// TODO use max_u64_base10_digits instead of hardcoding 20
var buf: [20]u8;
const len = buf_print_u64(buf.ptr, x);
return write(stdout_fileno, buf.ptr, len);
}
// TODO handle buffering and flushing (mutex protected)
// TODO error handling
pub fn print_i64(x: i64) -> isize {
// TODO use max_u64_base10_digits instead of hardcoding 20
var buf: [20]u8;
const len = buf_print_i64(buf.ptr, x);
return write(stdout_fileno, buf.ptr, len);
}
/*
// TODO error handling
pub fn readline(buf: []u8) -> ?[]u8 {
var index = 0;
while (index < buf.len) {
// TODO unknown size array indexing operator
const err = read(stdin_fileno, &buf.ptr[index], 1);
if (err != 0) {
return null;
}
// TODO unknown size array indexing operator
if (buf.ptr[index] == '\n') {
return buf[0...index + 1];
}
index += 1;
}
return null;
}
*/
fn digit_to_char(digit: u64) -> u8 {
'0' + (digit as u8)
}
const max_u64_base10_digits: usize = 20;
// TODO use an array for out_buf instead of pointer. this should give bounds checking in
// debug mode and length can get optimized out in release mode. requires array slicing syntax
// for the buf_print_u64 call.
fn buf_print_i64(out_buf: &u8, x: i64) -> usize {
if (x < 0) {
out_buf[0] = '-';
return 1 + buf_print_u64(&out_buf[1], ((-(x + 1)) as u64) + 1);
} else {
return buf_print_u64(out_buf, x as u64);
}
}
// TODO use an array for out_buf instead of pointer.
fn buf_print_u64(out_buf: &u8, x: u64) -> usize {
var buf: [max_u64_base10_digits]u8;
var a = x;
var index = buf.len;
while (true) {
const digit = a % 10;
index -= 1;
buf[index] = digit_to_char(digit);
a /= 10;
if (a == 0)
break;
}
const len = buf.len - index;
// TODO memcpy intrinsic
var i: usize = 0;
while (i < len) {
out_buf[i] = buf[index + i];
i += 1;
}
return len;
}