Maintenance Ruby 3.3 gets fixes, but no new features. Switch to Ruby 4.0 →
String.new
static VALUE
rb_str_init(int argc, VALUE *argv, VALUE str)
{
static ID keyword_ids[2];
VALUE orig, opt, venc, vcapa;
VALUE kwargs[2];
rb_encoding *enc = 0;
int n;
if (!keyword_ids[0]) {
keyword_ids[0] = rb_id_encoding();
CONST_ID(keyword_ids[1], "capacity");
}
n = rb_scan_args(argc, argv, "01:", &orig, &opt);
if (!NIL_P(opt)) {
rb_get_kwargs(opt, keyword_ids, 0, 2, kwargs);
venc = kwargs[0];
vcapa = kwargs[1];
if (!UNDEF_P(venc) && !NIL_P(venc)) {
enc = rb_to_encoding(venc);
}
if (!UNDEF_P(vcapa) && !NIL_P(vcapa)) {
long capa = NUM2LONG(vcapa);
long len = 0;
int termlen = enc ? rb_enc_mbminlen(enc) : 1;
if (capa < STR_BUF_MIN_SIZE) {
capa = STR_BUF_MIN_SIZE;
}
if (n == 1) {
StringValue(orig);
len = RSTRING_LEN(orig);
if (capa < len) {
capa = len;
}
if (orig == str) n = 0;
}
str_modifiable(str);
if (STR_EMBED_P(str)) { /* make noembed always */
char *new_ptr = ALLOC_N(char, (size_t)capa + termlen);
assert(RSTRING_LEN(str) + 1 <= str_embed_capa(str));
memcpy(new_ptr, RSTRING(str)->as.embed.ary, RSTRING_LEN(str) + 1);
RSTRING(str)->as.heap.ptr = new_ptr;
}
else if (FL_TEST(str, STR_SHARED|STR_NOFREE)) {
const size_t size = (size_t)capa + termlen;
const char *const old_ptr = RSTRING_PTR(str);
const size_t osize = RSTRING_LEN(str) + TERM_LEN(str);
char *new_ptr = ALLOC_N(char, (size_t)capa + termlen);
memcpy(new_ptr, old_ptr, osize < size ? osize : size);
FL_UNSET_RAW(str, STR_SHARED|STR_NOFREE);
RSTRING(str)->as.heap.ptr = new_ptr;
}
else if (STR_HEAP_SIZE(str) != (size_t)capa + termlen) {
SIZED_REALLOC_N(RSTRING(str)->as.heap.ptr, char,
(size_t)capa + termlen, STR_HEAP_SIZE(str));
}
STR_SET_LEN(str, len);
TERM_FILL(&RSTRING(str)->as.heap.ptr[len], termlen);
if (n == 1) {
memcpy(RSTRING(str)->as.heap.ptr, RSTRING_PTR(orig), len);
rb_enc_cr_str_exact_copy(str, orig);
}
FL_SET(str, STR_NOEMBED);
RSTRING(str)->as.heap.aux.capa = capa;
}
else if (n == 1) {
rb_str_replace(str, orig);
}
if (enc) {
rb_enc_associate(str, enc);
ENC_CODERANGE_CLEAR(str);
}
}
else if (n == 1) {
rb_str_replace(str, orig);
}
return str;
}
Returns a new String that is a copy of string.
With no arguments, returns the empty string with the Encoding ASCII-8BIT:
s = String.new s # => "" s.encoding # => #<Encoding:ASCII-8BIT>
With optional argument string and no keyword arguments, returns a copy of string with the same encoding:
String.new('foo') # => "foo" String.new('тест') # => "тест" String.new('こんにちは') # => "こんにちは"
(Unlike String.new, a string literal like '' or a here document literal always has script encoding.)
With optional keyword argument encoding, returns a copy of string with the specified encoding; the encoding may be an Encoding object, an encoding name, or an encoding name alias:
String.new('foo', encoding: Encoding::US_ASCII).encoding # => #<Encoding:US-ASCII> String.new('foo', encoding: 'US-ASCII').encoding # => #<Encoding:US-ASCII> String.new('foo', encoding: 'ASCII').encoding # => #<Encoding:US-ASCII>
The given encoding need not be valid for the string’s content, and that validity is not checked:
s = String.new('こんにちは', encoding: 'ascii') s.valid_encoding? # => false
But the given encoding itself is checked:
String.new('foo', encoding: 'bar') # Raises ArgumentError.
With optional keyword argument capacity, returns a copy of string (or an empty string, if string is not given); the given capacity is advisory only, and may or may not set the size of the internal buffer, which may in turn affect performance:
String.new(capacity: 1) String.new('foo', capacity: 4096)
The string, encoding, and capacity arguments may all be used together:
String.new('hello', encoding: 'UTF-8', capacity: 25)