Module: JsonEscape

Defined in:
lib/json_escape.rb,
lib/json_escape/version.rb,
ext/json_escape/json_escape.c

Defined Under Namespace

Modules: Pure

Constant Summary collapse

VERSION = 
"0.1.0"

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.json_escape ⇒ Object

Instance Method Details

#json_escape(str) ⇒ Object 



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# File 'ext/json_escape/json_escape.c', line 19

static VALUE
escape_json(VALUE self, VALUE str)
{
    if (!RB_TYPE_P(str, T_STRING)) {
        str = rb_convert_type(str, T_STRING, "String", "to_s");
    }

    rb_encoding *enc = rb_enc_get(str);
    if (enc != rb_utf8_encoding() && enc != rb_usascii_encoding()) {
        rb_raise(rb_eEncCompatError, "input string must be UTF-8 or ASCII");
    }

    const char *cstr = RSTRING_PTR(str);
    const unsigned long str_len = RSTRING_LEN(str);
    const char *end = cstr + RSTRING_LEN(str);

    size_t initial_match = strcspn(cstr, "&<>\xe2");
    if (initial_match == str_len) {
        return str;
    }

    VALUE escaped = rb_str_buf_new(json_escaped_length(str));
    rb_str_resize(escaped, json_escaped_length(str));
    char *buf = RSTRING_PTR(escaped);
    char *dest = buf;

    memcpy(dest, cstr, initial_match);
    cstr += initial_match;
    dest += initial_match;

    while (cstr < end) {
        const char c = *cstr++;

#define JSON_ESCAPE_CONCAT(s) do { \
    memcpy(dest, ("\\u" s), strlen(s) + 2); \
    dest += strlen(s) + 2; \
} while (0)

        if (0) {
        }
        else if (c == '&') {
            JSON_ESCAPE_CONCAT("0026");
        }
        else if (c == '>') {
            JSON_ESCAPE_CONCAT("003e");
        }
        else if (c == '<') {
            JSON_ESCAPE_CONCAT("003c");
        }
        else if (c == '\xe2' && cstr[0] == '\x80' && cstr[1] == '\xa8') {
            JSON_ESCAPE_CONCAT("2028");
            cstr += 2;
        }
        else if (c == '\xe2' && cstr[0] == '\x80' && cstr[1] == '\xa9') {
            JSON_ESCAPE_CONCAT("2029");
            cstr += 2;
        }
        else {
            *dest++ = c;
        }

        initial_match = strcspn(cstr, "&<>\xe2");
        memcpy(dest, cstr, initial_match);
        cstr += initial_match;
        dest += initial_match;

#undef JSON_ESCAPE_CONCAT
    }

    rb_str_resize(escaped, dest - buf);
    rb_enc_associate(escaped, rb_enc_get(str));

    return escaped;
}