class Enumerator::ArithmeticSequence
Enumerator::ArithmeticSequence is a subclass of Enumerator, that is a representation of sequences of numbers with common difference. Instances of this class can be generated by the Range#step and Numeric#step methods.
The class can be used for slicing Array (see Array#slice) or custom collections.
Public Instance Methods
aseq == obj → true or false
Returns true only if obj is an Enumerator::ArithmeticSequence, has equivalent begin, end, step, and exclude_end? settings.
static VALUE
arith_seq_eq(VALUE self, VALUE other)
{
if (!RTEST(rb_obj_is_kind_of(other, rb_cArithSeq))) {
return Qfalse;
}
if (!rb_equal(arith_seq_begin(self), arith_seq_begin(other))) {
return Qfalse;
}
if (!rb_equal(arith_seq_end(self), arith_seq_end(other))) {
return Qfalse;
}
if (!rb_equal(arith_seq_step(self), arith_seq_step(other))) {
return Qfalse;
}
if (arith_seq_exclude_end_p(self) != arith_seq_exclude_end_p(other)) {
return Qfalse;
}
return Qtrue;
}
===
Alias for: ==
begin → num or nil
Returns the number that defines the first element of this arithmetic sequence.
static inline VALUE
arith_seq_begin(VALUE self)
{
return rb_ivar_get(self, id_begin);
}
each {|i| block } → aseq
each → aseq
static VALUE
arith_seq_each(VALUE self)
{
VALUE c, e, s, len_1, last;
int x;
if (!rb_block_given_p()) return self;
c = arith_seq_begin(self);
e = arith_seq_end(self);
s = arith_seq_step(self);
x = arith_seq_exclude_end_p(self);
if (!RB_TYPE_P(s, T_COMPLEX) && ruby_float_step(c, e, s, x, TRUE)) {
return self;
}
if (NIL_P(e)) {
while (1) {
rb_yield(c);
c = rb_int_plus(c, s);
}
return self;
}
if (rb_equal(s, INT2FIX(0))) {
while (1) {
rb_yield(c);
}
return self;
}
len_1 = num_idiv(num_minus(e, c), s);
last = num_plus(c, num_mul(s, len_1));
if (x && rb_equal(last, e)) {
last = num_minus(last, s);
}
if (rb_num_negative_int_p(s)) {
while (NUM_GE(c, last)) {
rb_yield(c);
c = num_plus(c, s);
}
}
else {
while (NUM_GE(last, c)) {
rb_yield(c);
c = num_plus(c, s);
}
}
return self;
}
end → num or nil
Returns the number that defines the end of this arithmetic sequence.
static inline VALUE
arith_seq_end(VALUE self)
{
return rb_ivar_get(self, id_end);
}
eql?
Alias for: ==
exclude_end? → true or false
Returns true if this arithmetic sequence excludes its end value.
static inline VALUE
arith_seq_exclude_end(VALUE self)
{
return rb_ivar_get(self, id_exclude_end);
}
first → num or nil
first(n) → an_array
Returns the first number in this arithmetic sequence, or an array of the first n elements.
static VALUE
arith_seq_first(int argc, VALUE *argv, VALUE self)
{
VALUE b, e, s, ary;
long n;
int x;
rb_check_arity(argc, 0, 1);
b = arith_seq_begin(self);
e = arith_seq_end(self);
s = arith_seq_step(self);
if (argc == 0) {
if (NIL_P(b)) {
return Qnil;
}
if (!NIL_P(e)) {
VALUE zero = INT2FIX(0);
int r = rb_cmpint(rb_num_coerce_cmp(s, zero, idCmp), s, zero);
if (r > 0 && RTEST(rb_funcall(b, '>', 1, e))) {
return Qnil;
}
if (r < 0 && RTEST(rb_funcall(b, '<', 1, e))) {
return Qnil;
}
}
return b;
}
// TODO: the following code should be extracted as arith_seq_take
n = NUM2LONG(argv[0]);
if (n < 0) {
rb_raise(rb_eArgError, "attempt to take negative size");
}
if (n == 0) {
return rb_ary_new_capa(0);
}
x = arith_seq_exclude_end_p(self);
if (FIXNUM_P(b) && NIL_P(e) && FIXNUM_P(s)) {
long i = FIX2LONG(b), unit = FIX2LONG(s);
ary = rb_ary_new_capa(n);
while (n > 0 && FIXABLE(i)) {
rb_ary_push(ary, LONG2FIX(i));
i += unit; // FIXABLE + FIXABLE never overflow;
--n;
}
if (n > 0) {
b = LONG2NUM(i);
while (n > 0) {
rb_ary_push(ary, b);
b = rb_big_plus(b, s);
--n;
}
}
return ary;
}
else if (FIXNUM_P(b) && FIXNUM_P(e) && FIXNUM_P(s)) {
long i = FIX2LONG(b);
long end = FIX2LONG(e);
long unit = FIX2LONG(s);
long len;
if (unit >= 0) {
if (!x) end += 1;
len = end - i;
if (len < 0) len = 0;
ary = rb_ary_new_capa((n < len) ? n : len);
while (n > 0 && i < end) {
rb_ary_push(ary, LONG2FIX(i));
if (i + unit < i) break;
i += unit;
--n;
}
}
else {
if (!x) end -= 1;
len = i - end;
if (len < 0) len = 0;
ary = rb_ary_new_capa((n < len) ? n : len);
while (n > 0 && i > end) {
rb_ary_push(ary, LONG2FIX(i));
if (i + unit > i) break;
i += unit;
--n;
}
}
return ary;
}
else if (RB_FLOAT_TYPE_P(b) || RB_FLOAT_TYPE_P(e) || RB_FLOAT_TYPE_P(s)) {
/* generate values like ruby_float_step */
double unit = NUM2DBL(s);
double beg = NUM2DBL(b);
double end = NIL_P(e) ? (unit < 0 ? -1 : 1)*HUGE_VAL : NUM2DBL(e);
double len = ruby_float_step_size(beg, end, unit, x);
long i;
if (n > len)
n = (long)len;
if (isinf(unit)) {
if (len > 0) {
ary = rb_ary_new_capa(1);
rb_ary_push(ary, DBL2NUM(beg));
}
else {
ary = rb_ary_new_capa(0);
}
}
else if (unit == 0) {
VALUE val = DBL2NUM(beg);
ary = rb_ary_new_capa(n);
for (i = 0; i < len; ++i) {
rb_ary_push(ary, val);
}
}
else {
ary = rb_ary_new_capa(n);
for (i = 0; i < n; ++i) {
double d = i*unit+beg;
if (unit >= 0 ? end < d : d < end) d = end;
rb_ary_push(ary, DBL2NUM(d));
}
}
return ary;
}
return rb_call_super(argc, argv);
}
hash → integer
Compute a hash-value for this arithmetic sequence. Two arithmetic sequences with same begin, end, step, and exclude_end? values will generate the same hash-value.
See also Object#hash.
static VALUE
arith_seq_hash(VALUE self)
{
st_index_t hash;
VALUE v;
hash = rb_hash_start(arith_seq_exclude_end_p(self));
v = rb_hash(arith_seq_begin(self));
hash = rb_hash_uint(hash, NUM2LONG(v));
v = rb_hash(arith_seq_end(self));
hash = rb_hash_uint(hash, NUM2LONG(v));
v = rb_hash(arith_seq_step(self));
hash = rb_hash_uint(hash, NUM2LONG(v));
hash = rb_hash_end(hash);
return ST2FIX(hash);
}
inspect → string
Convert this arithmetic sequence to a printable form.
static VALUE
arith_seq_inspect(VALUE self)
{
struct enumerator *e;
VALUE eobj, str, eargs;
int range_p;
TypedData_Get_Struct(self, struct enumerator, &enumerator_data_type, e);
eobj = rb_attr_get(self, id_receiver);
if (NIL_P(eobj)) {
eobj = e->obj;
}
range_p = RTEST(rb_obj_is_kind_of(eobj, rb_cRange));
str = rb_sprintf("(%s%"PRIsVALUE"%s.", range_p ? "(" : "", eobj, range_p ? ")" : "");
rb_str_buf_append(str, rb_id2str(e->meth));
eargs = rb_attr_get(eobj, id_arguments);
if (NIL_P(eargs)) {
eargs = e->args;
}
if (eargs != Qfalse) {
long argc = RARRAY_LEN(eargs);
const VALUE *argv = RARRAY_CONST_PTR(eargs); /* WB: no new reference */
if (argc > 0) {
VALUE kwds = Qnil;
rb_str_buf_cat2(str, "(");
if (RB_TYPE_P(argv[argc-1], T_HASH)) {
int all_key = TRUE;
rb_hash_foreach(argv[argc-1], key_symbol_p, (VALUE)&all_key);
if (all_key) kwds = argv[--argc];
}
while (argc--) {
VALUE arg = *argv++;
rb_str_append(str, rb_inspect(arg));
rb_str_buf_cat2(str, ", ");
}
if (!NIL_P(kwds)) {
rb_hash_foreach(kwds, kwd_append, str);
}
rb_str_set_len(str, RSTRING_LEN(str)-2); /* drop the last ", " */
rb_str_buf_cat2(str, ")");
}
}
rb_str_buf_cat2(str, ")");
return str;
}
last → num or nil
last(n) → an_array
Returns the last number in this arithmetic sequence, or an array of the last n elements.
static VALUE
arith_seq_last(int argc, VALUE *argv, VALUE self)
{
VALUE b, e, s, len_1, len, last, nv, ary;
int last_is_adjusted;
long n;
e = arith_seq_end(self);
if (NIL_P(e)) {
rb_raise(rb_eRangeError,
"cannot get the last element of endless arithmetic sequence");
}
b = arith_seq_begin(self);
s = arith_seq_step(self);
len_1 = num_idiv(num_minus(e, b), s);
if (rb_num_negative_int_p(len_1)) {
if (argc == 0) {
return Qnil;
}
return rb_ary_new_capa(0);
}
last = num_plus(b, num_mul(s, len_1));
if ((last_is_adjusted = arith_seq_exclude_end_p(self) && rb_equal(last, e))) {
last = num_minus(last, s);
}
if (argc == 0) {
return last;
}
if (last_is_adjusted) {
len = len_1;
}
else {
len = rb_int_plus(len_1, INT2FIX(1));
}
rb_scan_args(argc, argv, "1", &nv);
if (!RB_INTEGER_TYPE_P(nv)) {
nv = rb_to_int(nv);
}
if (RTEST(rb_int_gt(nv, len))) {
nv = len;
}
n = NUM2LONG(nv);
if (n < 0) {
rb_raise(rb_eArgError, "negative array size");
}
ary = rb_ary_new_capa(n);
b = rb_int_minus(last, rb_int_mul(s, nv));
while (n) {
b = rb_int_plus(b, s);
rb_ary_push(ary, b);
--n;
}
return ary;
}
size → num or nil
Returns the number of elements in this arithmetic sequence if it is a finite sequence. Otherwise, returns nil.
static VALUE
arith_seq_size(VALUE self)
{
VALUE b, e, s, len_1, len, last;
int x;
b = arith_seq_begin(self);
e = arith_seq_end(self);
s = arith_seq_step(self);
x = arith_seq_exclude_end_p(self);
if (RB_FLOAT_TYPE_P(b) || RB_FLOAT_TYPE_P(e) || RB_FLOAT_TYPE_P(s)) {
double ee, n;
if (NIL_P(e)) {
if (rb_num_negative_int_p(s)) {
ee = -HUGE_VAL;
}
else {
ee = HUGE_VAL;
}
}
else {
ee = NUM2DBL(e);
}
n = ruby_float_step_size(NUM2DBL(b), ee, NUM2DBL(s), x);
if (isinf(n)) return DBL2NUM(n);
if (POSFIXABLE(n)) return LONG2FIX((long)n);
return rb_dbl2big(n);
}
if (NIL_P(e)) {
return DBL2NUM(HUGE_VAL);
}
if (!rb_obj_is_kind_of(s, rb_cNumeric)) {
s = rb_to_int(s);
}
if (rb_equal(s, INT2FIX(0))) {
return DBL2NUM(HUGE_VAL);
}
len_1 = rb_int_idiv(rb_int_minus(e, b), s);
if (rb_num_negative_int_p(len_1)) {
return INT2FIX(0);
}
last = rb_int_plus(b, rb_int_mul(s, len_1));
if (x && rb_equal(last, e)) {
len = len_1;
}
else {
len = rb_int_plus(len_1, INT2FIX(1));
}
return len;
}
step → num
Returns the number that defines the common difference between two adjacent elements in this arithmetic sequence.
static inline VALUE
arith_seq_step(VALUE self)
{
return rb_ivar_get(self, id_step);
}