Function escape_string

std/json/src/main/serializer.rs:187–215

(s: &str, out: &mut String, ensure_ascii: bool)

}

fn escape_string(s: &str, out: &mut String, ensure_ascii: bool) {
    out.push('"');
    for c in s.chars() {
        match c {
            '"' => out.push_str("\\\""),
            '\\' => out.push_str("\\\\"),
            '\n' => out.push_str("\\n"),
            '\r' => out.push_str("\\r"),
            '\t' => out.push_str("\\t"),
            '\u{08}' => out.push_str("\\b"),
            '\u{0C}' => out.push_str("\\f"),
            c if (c as u32) < 0x20 => out.push_str(&format!("\\u{:04x}", c as u32)),
            c if ensure_ascii && (c as u32) >= 0x80 => {
                let cp = c as u32;
                if cp <= 0xFFFF {
                    out.push_str(&format!("\\u{:04x}", cp));
                } else {
                    // UTF-16 surrogate pair for code points beyond the BMP.
                    let v = cp - 0x10000;
                    let hi = 0xD800 + (v >> 10);
                    let lo = 0xDC00 + (v & 0x3FF);
                    out.push_str(&format!("\\u{:04x}\\u{:04x}", hi, lo));
                }
            }
            c => out.push(c),
        }
    }
    out.push('"');
}

fn format_float(f: f64) -> String {
    // Integer-valued floats keep a trailing ".0" to disambiguate from int (Python's `json.dumps(1.0)` -> `"1.0"`).