/*

** array.c - Array class

**

** See Copyright Notice in mruby.h

*/

#include <mruby.h>

#include <mruby/array.h>

#include <mruby/class.h>

#include <mruby/string.h>

#include <mruby/range.h>

#include <mruby/proc.h>

#include <mruby/internal.h>

#include <mruby/presym.h>

#include "value_array.h"

#define ARY_DEFAULT_LEN 4

#define ARY_SHRINK_RATIO 5 /* must be larger than 2 */

#define ARY_C_MAX_SIZE (SIZE_MAX / sizeof(mrb_value))

#ifndef MRB_ARY_LENGTH_MAX

#define MRB_ARY_LENGTH_MAX 131072

#endif

#define ARY_MAX_SIZE ((mrb_int)((ARY_C_MAX_SIZE < (size_t)MRB_INT_MAX) ? ARY_C_MAX_SIZE : MRB_INT_MAX-1))

static void

ary_too_big(mrb_state *mrb)

{

mrb_raise(mrb, E_ARGUMENT_ERROR, "array size too big");

}

static inline void

ary_check_too_big(mrb_state *mrb, mrb_int a, mrb_int b)

{

if (a > ARY_MAX_SIZE - b || a < 0)

ary_too_big(mrb);

#if MRB_ARY_LENGTH_MAX != 0

if (a > MRB_ARY_LENGTH_MAX - b || a < 0)

ary_too_big(mrb);

#endif

}

static struct RArray*

ary_new_capa(mrb_state *mrb, mrb_int capa)

{

ary_check_too_big(mrb, capa, 0);

size_t blen = capa * sizeof(mrb_value);

struct RArray *a = MRB_OBJ_ALLOC(mrb, MRB_TT_ARRAY, mrb->array_class);

if (capa <= MRB_ARY_EMBED_LEN_MAX) {

ARY_SET_EMBED_LEN(a, 0);

}

else {

a->as.heap.ptr = (mrb_value *)mrb_malloc(mrb, blen);

a->as.heap.aux.capa = capa;

a->as.heap.len = 0;

}

return a;

}

/**

* Creates a new array with a specified initial capacity.

*

* This function allocates an array that can hold at least `capa` elements

* without needing to immediately reallocate memory. If `capa` is 0,

* it may still allocate a small default capacity.

*

* @param mrb The mruby state.

* @param capa The initial capacity desired for the array.

* @return A new mrb_value representing the created array.

*/

MRB_API mrb_value

mrb_ary_new_capa(mrb_state *mrb, mrb_int capa)

{

struct RArray *a = ary_new_capa(mrb, capa);

return mrb_obj_value(a);

}

/**

* Creates a new, empty array.

*

* This function is equivalent to calling `mrb_ary_new_capa` with a capacity of 0.

* The array will dynamically resize as elements are added.

*

* @param mrb The mruby state.

* @return A new mrb_value representing the created empty array.

*/

MRB_API mrb_value

mrb_ary_new(mrb_state *mrb)

{

return mrb_ary_new_capa(mrb, 0);

}

/*

* To copy array, use this instead of memcpy because of portability

* * gcc on ARM may fail optimization of memcpy

* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56620

* * gcc on MIPS also fail

* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=39755

* * memcpy doesn't exist on freestanding environment

*

* If you optimize for binary size, use memcpy instead of this at your own risk

* of above portability issue.

*

* See also https://togetter.com/li/462898 (Japanese)

*/

static inline void

array_copy(mrb_value *dst, const mrb_value *src, mrb_int size)

{

for (mrb_int i = 0; i < size; i++) {

dst[i] = src[i];

}

}

static struct RArray*

ary_new_from_values(mrb_state *mrb, mrb_int size, const mrb_value *vals)

{

struct RArray *a = ary_new_capa(mrb, size);

array_copy(ARY_PTR(a), vals, size);

ARY_SET_LEN(a, size);

return a;

}

/**

* Creates a new array initialized with a given sequence of values.

*

* This function allocates an array and copies `size` elements from the `vals`

* pointer into the new array.

*

* @param mrb The mruby state.

* @param size The number of values to initialize the array with.

* @param vals A pointer to an array of `mrb_value`s to copy into the new array.

* @return A new mrb_value representing the created array.

*/

MRB_API mrb_value

mrb_ary_new_from_values(mrb_state *mrb, mrb_int size, const mrb_value *vals)

{

struct RArray *a = ary_new_from_values(mrb, size, vals);

return mrb_obj_value(a);

}

/**

* Creates a new array of size 2, typically used to represent an association (key-value pair).

*

* The first element of the array is `car` (often the key), and the second element

* is `cdr` (often the value).

*

* @param mrb The mruby state.

* @param car The first value to be placed in the array.

* @param cdr The second value to be placed in the array.

* @return A new mrb_value representing the created 2-element array.

*/

MRB_API mrb_value

mrb_assoc_new(mrb_state *mrb, mrb_value car, mrb_value cdr)

{

struct RArray *a = ary_new_capa(mrb, 2);

mrb_value *p = ARY_PTR(a);

p[0] = car;

p[1] = cdr;

ARY_SET_LEN(a, 2);

return mrb_obj_value(a);

}

static void

ary_fill_with_nil(mrb_value *ptr, mrb_int size)

{

mrb_value nil = mrb_nil_value();

while (size--) {

*ptr++ = nil;

}

}

#define ary_modify_check(mrb, a) mrb_check_frozen((mrb), (a))

static void

ary_modify(mrb_state *mrb, struct RArray *a)

{

ary_modify_check(mrb, a);

if (ARY_SHARED_P(a)) {

mrb_shared_array *shared = a->as.heap.aux.shared;

if (shared->refcnt == 1 && a->as.heap.ptr == shared->ptr) {

a->as.heap.ptr = shared->ptr;

a->as.heap.aux.capa = a->as.heap.len;

mrb_free(mrb, shared);

}

else {

mrb_value *p = a->as.heap.ptr;

mrb_value *ptr = (mrb_value*)mrb_malloc(mrb, a->as.heap.len * sizeof(mrb_value));

if (p) {

array_copy(ptr, p, a->as.heap.len);

}

a->as.heap.ptr = ptr;

a->as.heap.aux.capa = a->as.heap.len;

mrb_ary_decref(mrb, shared);

}

ARY_UNSET_SHARED_FLAG(a);

}

}

/**

* Prepares an array for modification.

*

* This function ensures that the array is not frozen and is not shared.

* If the array is shared and has multiple references, this function will

* duplicate the array data to ensure that modifications do not affect

* other references. It also triggers a write barrier for the garbage collector.

*

* @param mrb The mruby state.

* @param a A pointer to the RArray structure to modify.

*/

MRB_API void

mrb_ary_modify(mrb_state *mrb, struct RArray* a)

{

mrb_write_barrier(mrb, (struct RBasic*)a);

ary_modify(mrb, a);

}

static void

ary_make_shared(mrb_state *mrb, struct RArray *a)

{

if (!ARY_SHARED_P(a) && !ARY_EMBED_P(a)) {

mrb_shared_array *shared = (mrb_shared_array*)mrb_malloc(mrb, sizeof(mrb_shared_array));

mrb_value *ptr = a->as.heap.ptr;

mrb_int len = a->as.heap.len;

shared->refcnt = 1;

if (a->as.heap.aux.capa > len) {

a->as.heap.ptr = shared->ptr = (mrb_value*)mrb_realloc(mrb, ptr, sizeof(mrb_value)*len+1);

}

else {

shared->ptr = ptr;

}

shared->len = len;

a->as.heap.aux.shared = shared;

ARY_SET_SHARED_FLAG(a);

}

}

static void

ary_expand_capa(mrb_state *mrb, struct RArray *a, mrb_int len)

{

mrb_int capa = ARY_CAPA(a);

ary_check_too_big(mrb, len, 0);

if (capa < ARY_DEFAULT_LEN) {

capa = ARY_DEFAULT_LEN;

}

while (capa < len) {

if (capa <= ARY_MAX_SIZE / 2) {

capa *= 2;

}

else {

capa = len;

}

}

if (capa > ARY_MAX_SIZE) {

ary_too_big(mrb);

}

if (ARY_EMBED_P(a)) {

mrb_value *ptr = ARY_EMBED_PTR(a);

mrb_int slen = ARY_EMBED_LEN(a);

mrb_value *expanded_ptr = (mrb_value*)mrb_malloc(mrb, sizeof(mrb_value)*capa);

ARY_UNSET_EMBED_FLAG(a);

array_copy(expanded_ptr, ptr, slen);

a->as.heap.len = slen;

a->as.heap.aux.capa = capa;

a->as.heap.ptr = expanded_ptr;

}

else if (capa > a->as.heap.aux.capa) {

mrb_value *expanded_ptr = (mrb_value*)mrb_realloc(mrb, a->as.heap.ptr, sizeof(mrb_value)*capa);

a->as.heap.aux.capa = capa;

a->as.heap.ptr = expanded_ptr;

}

}

static void

ary_shrink_capa(mrb_state *mrb, struct RArray *a)

{

if (ARY_EMBED_P(a)) return;

mrb_int capa = a->as.heap.aux.capa;

if (capa < ARY_DEFAULT_LEN * 2) return;

if (capa <= a->as.heap.len * ARY_SHRINK_RATIO) return;

do {

capa /= 2;

if (capa < ARY_DEFAULT_LEN) {

capa = ARY_DEFAULT_LEN;

break;

}

} while (capa > a->as.heap.len * ARY_SHRINK_RATIO);

if (capa > a->as.heap.len && capa < a->as.heap.aux.capa) {

a->as.heap.aux.capa = capa;

a->as.heap.ptr = (mrb_value*)mrb_realloc(mrb, a->as.heap.ptr, sizeof(mrb_value)*capa);

}

}

/**

* Resizes an array to a new length.

*

* If `new_len` is smaller than the current length, the array is truncated.

* If `new_len` is larger than the current length, the array is expanded,

* and new elements are filled with `nil`.

* This function modifies the array in place.

*

* @param mrb The mruby state.

* @param ary The array (mrb_value) to resize.

* @param new_len The desired new length of the array.

* @return The resized array (the same mrb_value as `ary`).

*/

MRB_API mrb_value

mrb_ary_resize(mrb_state *mrb, mrb_value ary, mrb_int new_len)

{

struct RArray *a = mrb_ary_ptr(ary);

ary_modify(mrb, a);

mrb_int old_len = RARRAY_LEN(ary);

if (old_len != new_len) {

if (new_len < old_len) {

ary_shrink_capa(mrb, a);

}

else {

ary_expand_capa(mrb, a, new_len);

ary_fill_with_nil(ARY_PTR(a) + old_len, new_len - old_len);

}

ARY_SET_LEN(a, new_len);

}

return ary;

}

static mrb_value

mrb_ary_s_create(mrb_state *mrb, mrb_value klass)

{

const mrb_value *vals;

mrb_int len;

mrb_get_args(mrb, "*!", &vals, &len);

mrb_value ary = mrb_ary_new_from_values(mrb, len, vals);

struct RArray *a = mrb_ary_ptr(ary);

a->c = mrb_class_ptr(klass);

return ary;

}

static void ary_replace(mrb_state*, struct RArray*, struct RArray*);

static mrb_value

mrb_ary_init(mrb_state *mrb, mrb_value ary)

{

mrb_value ss = mrb_fixnum_value(0);

mrb_value obj = mrb_nil_value();

mrb_value blk = mrb_nil_value();

mrb_get_args(mrb, "|oo&", &ss, &obj, &blk);

if (mrb_array_p(ss) && mrb_nil_p(obj) && mrb_nil_p(blk)) {

ary_replace(mrb, mrb_ary_ptr(ary), mrb_ary_ptr(ss));

return ary;

}

mrb_int size = mrb_as_int(mrb, ss);

struct RArray *a = mrb_ary_ptr(ary);

if (ARY_CAPA(a) < size) {

ary_expand_capa(mrb, a, size);

}

int ai = mrb_gc_arena_save(mrb);

for (mrb_int i=0; i<size; i++) {

mrb_value val;

if (mrb_nil_p(blk)) {

val = obj;

}

else {

val = mrb_yield(mrb, blk, mrb_fixnum_value(i));

}

mrb_ary_set(mrb, ary, i, val);

mrb_gc_arena_restore(mrb, ai); // for mrb_funcall

}

return ary;

}

static void

ary_concat(mrb_state *mrb, struct RArray *a, struct RArray *a2)

{

mrb_int len = ARY_LEN(a);

if (len == 0) {

ary_replace(mrb, a, a2);

return;

}

mrb_int len2 = ARY_LEN(a2);

ary_check_too_big(mrb, len2, len);

ary_modify(mrb, a);

mrb_int newlen = len + len2;

if (ARY_CAPA(a) < newlen) {

ary_expand_capa(mrb, a, newlen);

}

array_copy(ARY_PTR(a)+len, ARY_PTR(a2), len2);

mrb_write_barrier(mrb, (struct RBasic*)a);

ARY_SET_LEN(a, newlen);

}

/**

* Concatenates one array to another.

*

* Appends all elements from the `other` array to the `self` array.

* This function modifies the `self` array in place.

*

* @param mrb The mruby state.

* @param self The array (mrb_value) to which elements will be added.

* @param other The array (mrb_value) whose elements will be appended.

*/

MRB_API void

mrb_ary_concat(mrb_state *mrb, mrb_value self, mrb_value other)

{

struct RArray *a2 = mrb_ary_ptr(other);

ary_concat(mrb, mrb_ary_ptr(self), a2);

}

/*

* call-seq:

* array.concat(*other_arrays) -> self

*

* Adds to +array+ all elements from each \Array in +other_arrays+; returns +self+:

*

* a = [0, 1]

* a.concat([2, 3], [4, 5]) # => [0, 1, 2, 3, 4, 5]

*/

static mrb_value

mrb_ary_concat_m(mrb_state *mrb, mrb_value self)

{

mrb_value *args;

mrb_int len;

mrb_get_args(mrb, "*!", &args, &len);

for (int i=0; i<len; i++) {

mrb_ensure_array_type(mrb, args[i]);

}

for (int i=0; i<len; i++) {

mrb_ary_concat(mrb, self, args[i]);

}

return self;

}

static mrb_value

mrb_ary_plus(mrb_state *mrb, mrb_value self)

{

struct RArray *a1 = mrb_ary_ptr(self);

const mrb_value *ptr;

mrb_int blen;

mrb_get_args(mrb, "a", &ptr, &blen);

ary_check_too_big(mrb, ARY_LEN(a1), blen);

mrb_int len1 = ARY_LEN(a1);

struct RArray *a2 = ary_new_capa(mrb, len1 + blen);

array_copy(ARY_PTR(a2), ARY_PTR(a1), len1);

array_copy(ARY_PTR(a2) + len1, ptr, blen);

ARY_SET_LEN(a2, len1+blen);

return mrb_obj_value(a2);

}

#define ARY_REPLACE_SHARED_MIN 20

static void

ary_replace(mrb_state *mrb, struct RArray *a, struct RArray *b)

{

mrb_int len = ARY_LEN(b);

ary_modify_check(mrb, a);

if (a == b) return;

if (ARY_SHARED_P(a)) {

mrb_ary_decref(mrb, a->as.heap.aux.shared);

a->as.heap.aux.capa = 0;

a->as.heap.len = 0;

a->as.heap.ptr = NULL;

ARY_UNSET_SHARED_FLAG(a);

}

if (ARY_SHARED_P(b)) {

shared_b:

if (ARY_EMBED_P(a)) {

ARY_UNSET_EMBED_FLAG(a);

}

else {

mrb_free(mrb, a->as.heap.ptr);

}

a->as.heap.ptr = b->as.heap.ptr;

a->as.heap.len = len;

a->as.heap.aux.shared = b->as.heap.aux.shared;

a->as.heap.aux.shared->refcnt++;

ARY_SET_SHARED_FLAG(a);

mrb_write_barrier(mrb, (struct RBasic*)a);

return;

}

if (len > ARY_REPLACE_SHARED_MIN) {

ary_make_shared(mrb, b);

goto shared_b;

}

if (ARY_CAPA(a) < len)

ary_expand_capa(mrb, a, len);

array_copy(ARY_PTR(a), ARY_PTR(b), len);

mrb_write_barrier(mrb, (struct RBasic*)a);

ARY_SET_LEN(a, len);

}

/**

* Replaces the contents of an array with the contents of another array.

*

* After this operation, the `self` array will contain the same elements

* as the `other` array. This function modifies the `self` array in place.

*

* @param mrb The mruby state.

* @param self The array (mrb_value) whose contents will be replaced.

* @param other The array (mrb_value) from which to copy the elements.

*/

MRB_API void

mrb_ary_replace(mrb_state *mrb, mrb_value self, mrb_value other)

{

struct RArray *a1 = mrb_ary_ptr(self);

struct RArray *a2 = mrb_ary_ptr(other);

if (a1 != a2) {

ary_replace(mrb, a1, a2);

}

}

static mrb_value

mrb_ary_replace_m(mrb_state *mrb, mrb_value self)

{

mrb_value other;

mrb_get_args(mrb, "A", &other);

mrb_ary_replace(mrb, self, other);

return self;

}

static mrb_value

mrb_ary_times(mrb_state *mrb, mrb_value self)

{

struct RArray *a1 = mrb_ary_ptr(self);

mrb_value arg = mrb_get_arg1(mrb);

mrb_value tmp = mrb_check_string_type(mrb, arg);

if (!mrb_nil_p(tmp)) {

return mrb_ary_join(mrb, self, tmp);

}

mrb_int times = mrb_as_int(mrb, arg);

if (times < 0) {

mrb_raise(mrb, E_ARGUMENT_ERROR, "negative argument");

}

if (times == 0) return mrb_ary_new(mrb);

if (ARY_MAX_SIZE / times < ARY_LEN(a1)) {

ary_too_big(mrb);

}

mrb_int len1 = ARY_LEN(a1);

struct RArray *a2 = ary_new_capa(mrb, len1 * times);

ARY_SET_LEN(a2, len1 * times);

mrb_value *ptr = ARY_PTR(a2);

while (times--) {

array_copy(ptr, ARY_PTR(a1), len1);

ptr += len1;

}

return mrb_obj_value(a2);

}

static mrb_value

mrb_ary_reverse_bang(mrb_state *mrb, mrb_value self)

{

struct RArray *a = mrb_ary_ptr(self);

mrb_int len = ARY_LEN(a);

if (len > 1) {

ary_modify(mrb, a);

mrb_value *p1 = ARY_PTR(a);

mrb_value *p2 = p1 + len - 1;

while (p1 < p2) {

mrb_value tmp = *p1;

*p1++ = *p2;

*p2-- = tmp;

}

}

return self;

}

static mrb_value

mrb_ary_reverse(mrb_state *mrb, mrb_value self)

{

struct RArray *a = mrb_ary_ptr(self), *b = ary_new_capa(mrb, ARY_LEN(a));

mrb_int len = ARY_LEN(a);

if (len > 0) {

mrb_value *p1 = ARY_PTR(a);

mrb_value *e = p1 + len;

mrb_value *p2 = ARY_PTR(b) + len - 1;

while (p1 < e) {

*p2-- = *p1++;

}

ARY_SET_LEN(b, len);

}

return mrb_obj_value(b);

}

/**

* Pushes an element onto the end of an array.

*

* This function appends `elem` to the `ary` array, increasing its length by one.

* The array capacity may be expanded if necessary.

* This function modifies the array in place.

*

* @param mrb The mruby state.

* @param ary The array (mrb_value) to push the element onto.

* @param elem The mrb_value to append to the array.

*/

MRB_API void

mrb_ary_push(mrb_state *mrb, mrb_value ary, mrb_value elem)

{

struct RArray *a = mrb_ary_ptr(ary);

mrb_int len = ARY_LEN(a);

ary_modify(mrb, a);

if (len == ARY_CAPA(a))

ary_expand_capa(mrb, a, len + 1);

ARY_PTR(a)[len] = elem;

ARY_SET_LEN(a, len+1);

mrb_field_write_barrier_value(mrb, (struct RBasic*)a, elem);

}

static mrb_value

mrb_ary_push_m(mrb_state *mrb, mrb_value self)

{

mrb_int argc = mrb_get_argc(mrb);

if (argc == 1) {

mrb_ary_push(mrb, self, mrb_get_argv(mrb)[0]);

return self;

}

struct RArray *a = mrb_ary_ptr(self);

mrb_int len = ARY_LEN(a);

mrb_int len2 = len + argc;

ary_modify(mrb, a);

if (ARY_CAPA(a) < len2) {

ary_expand_capa(mrb, a, len2);

}

const mrb_value *argv = mrb_get_argv(mrb);

array_copy(ARY_PTR(a)+len, argv, argc);

ARY_SET_LEN(a, len2);

while (argc--) {

mrb_field_write_barrier_value(mrb, (struct RBasic*)a, *argv);

argv++;

}

return self;

}

/**

* Removes and returns the last element from an array.

*

* If the array is empty, returns `nil`.

* This function modifies the array in place.

*

* @param mrb The mruby state.

* @param ary The array (mrb_value) from which to pop the element.

* @return The last element of the array, or `nil` if the array is empty.

*/

MRB_API mrb_value

mrb_ary_pop(mrb_state *mrb, mrb_value ary)

{

struct RArray *a = mrb_ary_ptr(ary);

mrb_int len = ARY_LEN(a);

ary_modify_check(mrb, a);

if (len == 0) return mrb_nil_value();

ARY_SET_LEN(a, len-1);

return ARY_PTR(a)[len-1];

}

#define ARY_SHIFT_SHARED_MIN 10

/**

* Removes and returns the first element from an array.

*

* If the array is empty, returns `nil`.

* All other elements are shifted down by one index.

* This function modifies the array in place.

*

* @param mrb The mruby state.

* @param self The array (mrb_value) from which to shift the element.

* @return The first element of the array, or `nil` if the array is empty.

*/

MRB_API mrb_value

mrb_ary_shift(mrb_state *mrb, mrb_value self)

{

struct RArray *a = mrb_ary_ptr(self);

mrb_int len = ARY_LEN(a);

ary_modify_check(mrb, a);

if (len == 0) return mrb_nil_value();

if (ARY_SHARED_P(a)) {

L_SHIFT:

a->as.heap.ptr++;

a->as.heap.len--;

return a->as.heap.ptr[-1];

}

else if (len > ARY_SHIFT_SHARED_MIN) {

ary_make_shared(mrb, a);

goto L_SHIFT;

}

else {

mrb_value *ptr = ARY_PTR(a);

mrb_int size = len;

mrb_value val = *ptr;

while (--size) {

*ptr = *(ptr+1);

ptr++;

}

ARY_SET_LEN(a, len-1);

return val;

}

}

static mrb_value

mrb_ary_shift_m(mrb_state *mrb, mrb_value self)

{

if (mrb_get_argc(mrb) == 0) {

return mrb_ary_shift(mrb, self);

}

mrb_int n = mrb_as_int(mrb, mrb_get_arg1(mrb));

struct RArray *a = mrb_ary_ptr(self);

mrb_int len = ARY_LEN(a);

ary_modify_check(mrb, a);

if (len == 0 || n == 0) return mrb_ary_new(mrb);

if (n < 0) mrb_raise(mrb, E_ARGUMENT_ERROR, "negative array shift");

if (n > len) n = len;

mrb_value val = mrb_ary_new_from_values(mrb, n, ARY_PTR(a));

if (ARY_SHARED_P(a)) {

L_SHIFT:

a->as.heap.ptr+=n;

a->as.heap.len-=n;

return val;

}

if (len > ARY_SHIFT_SHARED_MIN) {

ary_make_shared(mrb, a);

goto L_SHIFT;

}

else if (len == n) {

ARY_SET_LEN(a, 0);

}

else {

mrb_value *ptr = ARY_PTR(a);

mrb_int size = len-n;

while (size--) {

*ptr = *(ptr+n);

ptr++;

}

ARY_SET_LEN(a, len-n);

}

return val;

}

/* self = [1,2,3]

item = 0

self.unshift item

p self #=> [0, 1, 2, 3] */

/**

* Prepends an element to the beginning of an array.

*

* This function adds `item` to the front of the `self` array,

* shifting all existing elements up by one index.

* The array capacity may be expanded if necessary.

* This function modifies the array in place.

*

* @param mrb The mruby state.

* @param self The array (mrb_value) to unshift the element onto.

* @param item The mrb_value to prepend to the array.

* @return The modified array (the same mrb_value as `self`).

*/

MRB_API mrb_value

mrb_ary_unshift(mrb_state *mrb, mrb_value self, mrb_value item)

{

struct RArray *a = mrb_ary_ptr(self);

mrb_int len = ARY_LEN(a);

if (ARY_SHARED_P(a)

&& a->as.heap.aux.shared->refcnt == 1 /* shared only referenced from this array */

&& a->as.heap.ptr - a->as.heap.aux.shared->ptr >= 1) /* there's room for unshifted item */ {

a->as.heap.ptr--;

a->as.heap.ptr[0] = item;

}

else {

mrb_value *ptr;

ary_modify(mrb, a);

if (ARY_CAPA(a) < len + 1)

ary_expand_capa(mrb, a, len + 1);

ptr = ARY_PTR(a);

value_move(ptr + 1, ptr, len);

ptr[0] = item;

}

ARY_SET_LEN(a, len+1);

mrb_field_write_barrier_value(mrb, (struct RBasic*)a, item);

return self;

}

/*

* call-seq:

* array.unshift(*objects) -> self

*

* Prepends the given +objects+ to +self+:

*

* a = [:foo, 'bar', 2]

* a.unshift(:bam, :bat) # => [:bam, :bat, :foo, "bar", 2]

*

* Array#prepend is an alias for Array#unshift.

*

* Related: #push, #pop, #shift.

*/

static mrb_value

mrb_ary_unshift_m(mrb_state *mrb, mrb_value self)

{

struct RArray *a = mrb_ary_ptr(self);

mrb_value *ptr;

mrb_int alen = mrb_get_argc(mrb);

if (alen == 0) {

ary_modify_check(mrb, a);

return self;

}

const mrb_value *vals = mrb_get_argv(mrb);

mrb_int len = ARY_LEN(a);

if (alen > ARY_MAX_SIZE - len) {

ary_too_big(mrb);

}

if (ARY_SHARED_P(a)

&& a->as.heap.aux.shared->refcnt == 1 /* shared only referenced from this array */

&& a->as.heap.ptr - a->as.heap.aux.shared->ptr >= alen) /* there's room for unshifted item */ {

ary_modify_check(mrb, a);

a->as.heap.ptr -= alen;

ptr = a->as.heap.ptr;

}

else {

mrb_bool same = vals == ARY_PTR(a);

ary_modify(mrb, a);

if (ARY_CAPA(a) < len + alen)

ary_expand_capa(mrb, a, len + alen);

ptr = ARY_PTR(a);

value_move(ptr + alen, ptr, len);

if (same) vals = ptr;

}

array_copy(ptr, vals, alen);

ARY_SET_LEN(a, len+alen);

while (alen--) {

mrb_field_write_barrier_value(mrb, (struct RBasic*)a, vals[alen]);

}

return self;

}

/**

* Sets the element at a given index in an array.

*

* If `n` is within the current bounds of the array, the element at that index

* is replaced with `val`.

* If `n` is beyond the current bounds, the array is expanded to accommodate

* the new element, and any intermediate elements are filled with `nil`.

* If `n` is negative, it counts from the end of the array.

* An IndexError is raised if a negative index points past the beginning of the array.

* This function modifies the array in place.

*

* @param mrb The mruby state.

* @param ary The array (mrb_value) to modify.

* @param n The index at which to set the element.

* @param val The mrb_value to set at the specified index.

*/

MRB_API void

mrb_ary_set(mrb_state *mrb, mrb_value ary, mrb_int n, mrb_value val)

{

struct RArray *a = mrb_ary_ptr(ary);

mrb_int len = ARY_LEN(a);

ary_modify(mrb, a);

/* range check */

if (n < 0) {

n += len;

if (n < 0) {

mrb_raisef(mrb, E_INDEX_ERROR, "index %i out of array", n - len);

}

}

if (n >= ARY_MAX_SIZE) {

mrb_raise(mrb, E_INDEX_ERROR, "index too big");

}

if (len <= n) {

if (ARY_CAPA(a) <= n)

ary_expand_capa(mrb, a, n + 1);

ary_fill_with_nil(ARY_PTR(a) + len, n + 1 - len);

ARY_SET_LEN(a, n+1);

}

ARY_PTR(a)[n] = val;

mrb_field_write_barrier_value(mrb, (struct RBasic*)a, val);

}

static struct RArray*

ary_dup(mrb_state *mrb, struct RArray *a)

{

return ary_new_from_values(mrb, ARY_LEN(a), ARY_PTR(a));

}

MRB_API mrb_value

mrb_ary_dup(mrb_state *mrb, mrb_value ary)

{

return mrb_obj_value(ary_dup(mrb, mrb_ary_ptr(ary)));

}

/**

* Replaces a portion of an array with elements from another array or a single value.

*

* Removes `len` elements from `ary` starting at `head` index, and inserts

* the elements from `rpl` (if `rpl` is an array) or `rpl` itself (if it's not an array)

* at that position.

* If `head` is negative, it counts from the end of the array.

* If `len` is negative, an IndexError is raised.

* If `rpl` is `mrb_undef_p()`, then the elements are removed without replacement.

* This function modifies the `ary` array in place.

*

* @param mrb The mruby state.

* @param ary The array (mrb_value) to modify.

* @param head The starting index for the splice operation.

* @param len The number of elements to remove.

* @param rpl The mrb_value to insert (can be an array or a single value, or mrb_undef_p()).

* @return The modified array (the same mrb_value as `ary`).

*/

MRB_API mrb_value

mrb_ary_splice(mrb_state *mrb, mrb_value ary, mrb_int head, mrb_int len, mrb_value rpl)

{

struct RArray *a = mrb_ary_ptr(ary);

mrb_int alen = ARY_LEN(a);

const mrb_value *argv;

mrb_int argc;

mrb_int tail;

ary_modify(mrb, a);

/* len check */

if (len < 0) mrb_raisef(mrb, E_INDEX_ERROR, "negative length (%i)", len);

/* range check */

if (head < 0) {

head += alen;

if (head < 0) goto out_of_range;

}

if (head > ARY_MAX_SIZE - len) {

out_of_range:

mrb_raisef(mrb, E_INDEX_ERROR, "index %i is out of array", head);

}

tail = head + len;

if (alen < len || alen < tail) {

len = alen - head;

tail = head + len;

}

/* size check */

if (mrb_array_p(rpl)) {

argc = RARRAY_LEN(rpl);

argv = RARRAY_PTR(rpl);

if (argv == ARY_PTR(a)) {

struct RArray *r;

if (argc > 32767) {