use o3::buffer::Owned;
pub struct Encode;
impl Encode {
pub fn u64_len(mut value: u64) -> usize {
if value == 0 {
return 1;
}
let mut digits = 0usize;
while value != 0 {
digits += 1;
value /= 10;
}
digits
}
pub fn str_len(value: &[u8]) -> usize {
2 + Self::esc_len(value)
}
pub fn extend_str(value: &[u8], out: &mut Owned) {
out.extend_from_slice(b"\"");
let mut start = 0usize;
let mut idx = 0usize;
while idx < value.len() {
let esc = Self::esc_token(value[idx]);
if let Some(token) = esc {
if start != idx {
out.extend_from_slice(&value[start..idx]);
}
out.extend_from_slice(token.as_bytes());
idx += 1;
start = idx;
continue;
}
idx += 1;
}
if start != value.len() {
out.extend_from_slice(&value[start..]);
}
out.extend_from_slice(b"\"");
}
pub fn extend_u64(out: &mut Owned, value: u64) {
if value == 0 {
out.extend_from_slice(b"0");
return;
}
let mut digits = [0u8; 20];
let mut idx = digits.len();
let mut value = value;
while value != 0 {
idx -= 1;
digits[idx] = b'0' + (value % 10) as u8;
value /= 10;
}
out.extend_from_slice(&digits[idx..]);
}
fn esc_len(value: &[u8]) -> usize {
let mut len = 0usize;
let mut idx = 0usize;
while idx < value.len() {
len += Self::esc_size(value[idx]);
idx += 1;
}
len
}
fn esc_size(byte: u8) -> usize {
match byte {
b'"' | b'\\' | 0x08 | b'\n' | 0x0c | b'\r' | b'\t' => 2,
0x00..=0x1f => 6,
_ => 1,
}
}
fn esc_token(byte: u8) -> Option<&'static str> {
match byte {
b'"' => Some("\\\""),
b'\\' => Some("\\\\"),
b'\n' => Some("\\n"),
b'\r' => Some("\\r"),
b'\t' => Some("\\t"),
0x00 => Some("\\u0000"),
0x01 => Some("\\u0001"),
0x02 => Some("\\u0002"),
0x03 => Some("\\u0003"),
0x04 => Some("\\u0004"),
0x05 => Some("\\u0005"),
0x06 => Some("\\u0006"),
0x07 => Some("\\u0007"),
0x08 => Some("\\b"),
0x0b => Some("\\u000b"),
0x0c => Some("\\f"),
0x0e => Some("\\u000e"),
0x0f => Some("\\u000f"),
0x10 => Some("\\u0010"),
0x11 => Some("\\u0011"),
0x12 => Some("\\u0012"),
0x13 => Some("\\u0013"),
0x14 => Some("\\u0014"),
0x15 => Some("\\u0015"),
0x16 => Some("\\u0016"),
0x17 => Some("\\u0017"),
0x18 => Some("\\u0018"),
0x19 => Some("\\u0019"),
0x1a => Some("\\u001a"),
0x1b => Some("\\u001b"),
0x1c => Some("\\u001c"),
0x1d => Some("\\u001d"),
0x1e => Some("\\u001e"),
0x1f => Some("\\u001f"),
_ => None,
}
}
}